WO2019159619A1 - Mobile unit - Google Patents

Abstract

A mobile unit 1A including a vehicle body 2, a front wheel 3f (steered wheel), a rear wheel 3r, and a steering operation unit 7 comprises: a trail length variable mechanism 9; a steering actuator 8; a trail length changing actuator 15; and a control device 50. The control device 50 controls the steering actuator 8 so as to apply, to the steering operation unit 7, a steering torque in the same direction as the steering direction of the front wheel 3f.

Description

Moving body

The present invention relates to a moving body such as a motorcycle.

2. Description of the Related Art Conventionally, a moving body such as a two-wheeled vehicle is configured so that a trail length can be changed as seen in, for example, Patent Documents 1 and 2. In this moving body, in the speed range on the low speed side, the posture control of the vehicle body is performed by the steering control of the front wheels while the trail length is controlled to a small trail length such as a negative trail length. Further, in the high speed side speed range, the trail length is controlled to be a positive trail length in the same manner as in a normal two-wheeled vehicle, thereby realizing the same running characteristics as in a normal two-wheeled vehicle.

The positive trail length is the trail length when the intersection of the front wheel steering axis and the road surface is located in front of the front wheel grounding point, and the negative trail length is the front wheel steering axis and the road surface. This is the trail length when the intersection is located behind the ground contact point of the front wheel.

JP 2014-172586 A US Pat. No. 9,162,726

By the way, a normal two-wheeled vehicle having a positive trail length naturally generates a steering moment around the steering axis so as to turn the front wheel toward the turning direction side due to so-called self-steering characteristics during turning. The steering torque corresponding to the steering moment acts on the steering operation portion (handle).

On the other hand, according to various studies by the inventors of the present application, in a moving body such as that disclosed in Patent Documents 1 and 2, when the trail length is controlled to a small trail length such as a negative value, Steering moment acting to turn in the turning direction side hardly occurs around the steering axis, or a reverse steering moment occurs (as a result, steering torque acting on the steering operation portion hardly occurs or steering It was found that a steering torque in the direction opposite to the direction acts on the steering operation unit).

Therefore, an object of the present invention is to provide a moving body capable of changing the trail length and capable of realizing the same steering characteristics as a normal two-wheeled vehicle during turning.

In order to achieve the above object, a moving body according to the present invention includes a vehicle body and front and rear wheels arranged at intervals in the front-rear direction of the vehicle body, and the front wheels are steered around a steering axis. A movable body including a steering operation unit for a driver to steer the front wheel,
A front wheel support mechanism having a trail length variable mechanism for changing the trail length of the front wheel and configured to support the front wheel so as to be steerable around the steering axis;
A steering actuator for generating a driving force for steering the front wheels;
A trail length changing actuator for generating a driving force for changing the trail length of the front wheel;
A control device for controlling the steering actuator and the trail length changing actuator,
The control device is configured to control the steering actuator so as to apply a steering torque in the same direction as the steering direction of the front wheels to the steering operation unit (first invention).

According to this, it becomes possible to apply a steering torque in the same direction as the steering direction of the front wheels to the steering operation unit regardless of the trail length of the front wheels. Therefore, according to the first aspect of the present invention, it is possible to achieve the same steering characteristics as those of a normal two-wheeled vehicle or the like during turning while the mobile body that can change the trail length.

In the first aspect of the invention, the trail length variable mechanism may be configured to change the trail length of the front wheel between a positive upper limit trail length and a negative lower limit trail length. In this case, the control device is configured to control the steering actuator so as to apply the steering torque to the steering operation unit at least in a state where the trail length of the front wheel is a negative trail length. It is preferable (2nd invention).

In the present invention, the positive trail length (including the positive upper limit trail length) is the posture state when the moving body travels straight on a horizontal ground surface (specifically, the moving body is the center of the axle of the front wheel). Trail when the intersection of the steering axis and the grounding surface is located in front of the grounding point of the front wheel with the line parallel to the axle centerline of the rear wheel and standing on a horizontal grounding surface) The long and negative trail length (including the negative lower limit trail length) means the trail length when the intersection of the steering axis and the ground contact surface is located behind the ground contact point of the front wheels.

Here, when the front wheel is steered (rotated around the steering axis) without generating the driving force of the steering actuator in a state where the trail length of the moving body is a negative trail length, the steering operation is performed. Almost no steering torque is generated with respect to the portion, or a steering torque in the direction opposite to the steering direction of the front wheels acts on the steering operation portion.

However, according to the second aspect of the invention, the steering torque in the same direction as the steering direction of the front wheels is applied to the steering operation portion even when the trail length of the moving body is a negative trail length by operating the steering actuator. Can be granted. As a result, the same steering torque as in the state where the trail length of the moving body is a positive trail length can be applied to the steering operation section.

In the second aspect of the invention, the control device controls the trail length changing actuator to change the trail length of the front wheel from a negative trail length to a positive trail length as the traveling speed of the moving body increases. Can be configured to. In this case, it is preferable that the control device is configured to control the steering actuator so as to weaken the steering torque as the traveling speed increases (third invention).

According to this, it is possible to suppress the steering torque applied to the steering operation unit from fluctuating according to the change in the trail length according to the traveling speed of the moving body.

In the first to third inventions, it is preferable that the control device is configured to determine the steering torque in accordance with an observed value of the steering angle of the front wheels (fourth invention).

According to this, it is possible to apply a steering torque matched to the steering angle of the front wheels to the steering operation unit.

In the fourth aspect of the invention, the control device determines the relationship between the steering angle of the front wheel when the trail length of the front wheel is a positive predetermined value and the torque acting on the steering operation unit according to the steering angle. It is preferable that stored correlation data is stored and the steering torque is determined based on the correlation data from the observed value of the steering angle of the front wheels (fifth invention).

According to this, it is possible to apply the same steering torque to the steering operation unit as in the case where the trail length is maintained at the positive predetermined value regardless of the change in the trail length.

The figure which shows the two-wheeled vehicle for demonstrating the basic technical matter regarding this invention. Explanatory drawing regarding the dynamic action | operation of the front-wheel side part of the two-wheeled vehicle shown in FIG. The graph which illustrates the characteristic of the change with respect to the trail length of the ratio (Mstr / δf) of the steering moment generated around the steering axis of the front wheel of the two-wheeled vehicle shown in FIG. 1 and the steering angle of the front wheel. The side view which shows the two-wheeled vehicle as a moving body of embodiment. FIG. 5 is a sectional view taken along line AA in FIG. 4. FIG. 6 is a sectional view taken along line BB in FIG. 5. The block diagram which shows the structure regarding the control of the two-wheeled vehicle of embodiment. The block diagram which shows the main functions of the control apparatus shown in FIG. The figure which shows the mass system (2 mass system) for expressing the dynamics of the two-wheeled vehicle of embodiment. The graph for demonstrating an example of the process of the target trail length determination part shown in FIG. 8, and the control process of the actual trail length according to the target trail length. The graph for demonstrating the other example of the process of the target trail length determination part shown in FIG. 8, and the control process of the actual trail length according to the target trail length. The block diagram which shows the process of the attitude | position control calculating part shown in FIG. 13A, 13B, and 13C are graphs for explaining the processing of the control gain determination unit shown in FIG.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 13C.
(Explanation of basic matters)
First, basic technical matters relating to the present invention will be described with reference to FIGS. FIG. 1 schematically shows a two-wheeled vehicle 1 as a representative example of a moving body including a vehicle body 2 and a front wheel 3f and a rear wheel 3r arranged at intervals in the front-rear direction of the vehicle body 2 in a side view. . In FIG. 1, the rear wheel 3 r viewed from the rear side of the two-wheeled vehicle 1 and the front wheel 3 f viewed from the front side of the two-wheeled vehicle 1 are shown together on the left and right sides of the two-wheeled vehicle 1 in a side view. ing.

The front wheel 3 f is rotatably supported by a front wheel support mechanism 4 provided at the front portion of the vehicle body 2. The front wheel support mechanism 4 can be constituted by a front fork, for example. The front wheel 3f is a steerable wheel that can be steered (rotatable) about a steered steering axis Csf.

The steering axis Csf is tilted backward because the steering axis Csf is positioned so that the upper side of the steering axis Csf is relatively rearward in the longitudinal direction of the vehicle body 2 than the lower side of the steering axis Csf. It means that it is inclined and extended.

The rear wheel 3r is rotatably supported by a rear wheel support mechanism 5 provided at the rear part of the vehicle body 2. The rear wheel support mechanism 5 can be constituted by, for example, a swing arm or the like. The rear wheel 3r is a non-steering wheel.

In the two-wheeled vehicle 1 having the above-described structure, the front wheel 3 is rotated around the steering axis Csf according to the steering (rotation around the steering axis Csf) of the front wheel 3f in a state where the steering force is not applied from the handle (not shown in FIG. 1). The moment Mstr generated in the following (hereinafter referred to as the steering moment Mstr) will be described below. The steering moment Mstr corresponds to a moment generated by a so-called self-steer characteristic of a two-wheeled vehicle.

In the following description, as shown in FIG. 1, the two-wheeled vehicle 1 travels straight on a horizontal ground surface 110 (road surface) (an attitude in which the axle centerline of the front wheel 3f is parallel to the axle centerline of the rear wheel 3r). ) Is called a reference posture state of the motorcycle 1. Further, as shown in FIGS. 1 and 2, the front-rear direction, the left-right direction (vehicle width direction), and the height direction (vertical direction) of the vehicle body 2 of the two-wheeled vehicle 1 in the reference posture state are set in the X-axis direction of the XYZ coordinate system. , Y-axis direction and Z-axis direction.

According to the study of the present inventor, the steering moment Mstr is the gravity acting on the front wheel side portion of the two-wheeled vehicle 1 (specifically, the portion including the front wheel 3f and capable of rotating with the front wheel 3f around the steering axis Csf), It is considered that the dependence on the road surface reaction force (contact load) acting on the front wheel 3f out of the road surface reaction forces acting on the front wheel 3f and the rear wheel 3r against the gravity acting on the entire motorcycle 1 is high.

Note that “G” in FIG. 1 exemplarily shows the overall center of gravity of the two-wheeled vehicle 1, and “Gf” shows the center of gravity of the front wheel side portion (hereinafter referred to as the front wheel side center of gravity).

In this case, the dynamic model representing the relationship between the steering angle δf (rotation angle around the steering axis Csf) of the front wheel 3f and the steering moment Mstr is approximately expressed by It can be expressed by (1). In the present specification, “*” means a multiplication symbol.

 

 

1 and 2, m in the equation (1) is the total mass of the motorcycle 1 (mass point mass of the overall center of gravity G), g is the gravitational acceleration constant, and Lf is the motorcycle 1 in the reference posture state. The distance in the X-axis direction between the overall center of gravity G of the vehicle and the ground point of the front wheel 3f, Lr is the distance in the X-axis direction between the overall center of gravity G of the motorcycle 1 in the reference posture state and the ground point of the rear wheel 3r, mf is the mass of the front wheel side portion of the motorcycle 1 (mass point mass of the front wheel center of gravity Gf), and a is a straight line (straight line in the Z-axis direction) passing through the ground point of the front wheel 3f of the motorcycle 1 in the reference posture state and the axle center point. ) And the height of the intersection Ef of the steering axis Csf from the ground contact surface 110 (the distance between the intersection Ef and the ground contact of the front wheel 3f).

Note that the intersection point Ef is not limited to being located above the ground contact surface 110 as shown in FIG. 1, but depending on the positional relationship between the steering axis Csf and the front wheel 3f, In some cases, it is located below the ground plane 110.

In the description of the present embodiment, with respect to the height a of the intersection point Ef, the intersection point Ef is located above the ground plane 110 (in other words, the intersection point between the steering axis Csf and the ground plane 110 is shown in FIG. 1). The polarity of the height a in the case where the front wheel 3f is located on the front side of the grounding point) is positive (a> 0), and the intersection point Ef is located on the lower side of the grounding surface 110 (in other words, The polarity of the height a at the intersection of the steering axis Csf and the ground contact surface 110 is located behind the ground contact point of the front wheel 3f) is negative (a <0).

Rf in equation (1) is the curvature radius of the cross-sectional shape of the front wheel 3f at the position of the ground contact point of the front wheel 3f in the reference posture state, and hgf is the contact of the front wheel side center of gravity Gf of the motorcycle 1 in the reference posture state. The height from the ground 110, h is the height from the ground contact surface 110 of the overall center of gravity G of the two-wheeled vehicle 1 in the reference posture, and I is the axis Crol in the front-rear direction (X-axis direction) passing through the overall center of gravity G. The overall moment of inertia of the motorcycle 1 (hereinafter referred to as overall inertia I), θcf, is a caster angle as an inclination angle of the steering axis Csf (inclination angle with respect to the Z-axis direction).

Further, in the expression (1), the steering angle δf of the front wheel 3f in the reference posture state of the two-wheeled vehicle 1 (hereinafter simply referred to as the front wheel steering angle δf) is zero, the forward direction of the front wheel steering angle δf, and the steering moment The positive direction of Mstr is the direction in which the front wheel 3f rotates counterclockwise around the steering axis Csf when the two-wheeled vehicle 1 in the reference posture is viewed from above.

The above formula (1) is derived from the following relational expressions (2-1) to (2-8).

 

 

Here, with reference to FIG. 2, φf in the equations (2-1) to (2-8) is the inclination angle of the front wheel 3f in the roll direction (direction around the X axis), and ef is the roll direction of the front wheel 3f. The amount of movement of the intersection Ef in the lateral direction (Y-axis direction) associated with the inclination (inclination from the reference attitude state), pf is the front wheel 3f in accordance with the inclination of the front wheel 3f in the roll direction (inclination from the reference attitude state). The amount of movement of the ground contact point in the lateral direction (Y-axis direction), pgf is the amount of movement of the front wheel side center of gravity Gf in the lateral direction (Y-axis direction) accompanying the inclination of the front wheel 3f in the roll direction (inclination from the reference posture state), Ff is the road surface reaction force (ground contact load) acting on the front wheel 3f out of the road surface reaction forces acting on the front wheel 3f and the rear wheel 3r against the gravity acting on the entire motorcycle 1, and Mef is the front wheel side center of gravity Gf. By the gravity acting on the road (= mf * g) and the road surface reaction force Ff acting on the front wheel 3f. It is a moment generated in the roll direction in the f. Although not shown, φb is an inclination angle in the roll direction of the vehicle body 2 that occurs in response to the steering of the front wheels 3f.

In this case, the inclination angles φf and φb in the reference posture state of the motorcycle 1 are zero, and the positive directions of the inclination angles φf and φb and the moment Mef are clockwise when the motorcycle 1 is viewed from the back side. is there. Further, the positive directions of the movement amounts ef, pf, and pgf are leftward directions when the two-wheeled vehicle 1 is viewed from the back side.

Expressions (2-1), (2-2), and (2-3) are the same expressions as Expressions (8), (11), and (16) described in Patent Documents 1 and 2, respectively. is there.

The expression (1) is rewritten into the expression (3) when variables kstr and astr defined by the following expressions (3a) and (3b) are introduced.

 

 

Furthermore, a trail length t (see FIG. 1), which is a distance from the contact point of the front wheel 3f, of the intersection point of the steering axis Csf and the contact surface 110 in the reference posture state of the two-wheeled vehicle 1, and the height a of the intersection point Ef, The relationship of following Formula (4) is materialized between.

t = a * tan (θcf) (4)

Therefore, Expression (3) can be rewritten into the following Expression (5) using the trail length t.

Mstr = (kstr / tan (θcf)) * (t−astr * tan (θcf)) * δf (5)

In the description of the present embodiment, the polarity of the trail length t is the same as the polarity of the height a of the intersection Ef, and the intersection of the steering axis Csf of the two-wheeled vehicle 1 in the reference posture state and the ground plane 110 is shown in FIG. As shown in FIG. 1, the trail length t is positive (t> 0) when located on the front side of the ground point of the front wheel 3f, and the intersection of the steering axis Csf and the ground surface 110 is behind the ground point of the front wheel 3f. The trail length t when positioned is negative (t <0).

As can be seen from the above equation (5), the steering moment Mstr is proportional to the front wheel steering angle δf when the trail length t is constant (when the height a is constant). Further, when the front wheel steering angle δf is constant, the magnitude and polarity (direction) of the steering moment Mstr change according to the trail length t.

More specifically, since the value of the variable kstr is generally a positive value, when focusing on the ratio Mstr / δf between the steering moment Mstr and the front wheel steering angle δf (where δf ≠ 0), the ratio Mstr / δf The value changes as shown in the graph of FIG. 3, for example, with respect to the change in the trail length t.

In this case, as can be seen from the equation (5), when the trail length t is t> astr * tan (θcf)) (when a> astr), the polarity (direction) of the steering moment Mstr is the front wheel It coincides with the polarity (direction) of the steering angle δf (Mstr / δf> 0). This corresponds to the self-steer characteristic in a normal motorcycle. In this case, if the trail length t of the two-wheeled vehicle 1 is set to a positive trail length that is about the same size as that of a normal two-wheeled vehicle, for example, the same self-steering characteristic as that of a normal two-wheeled vehicle can be realized.

On the other hand, when the trail length t is t <astr * tan (θcf)) (in other words, when a <astr), the polarity (direction) of the steering moment Mstr is the polarity of the front wheel steering angle δf ( Direction) (Mstr / δ <0). For this reason, when the trail length t is set to a negative trail length smaller than astr * tan (θcf)), the polarity (direction) of the steering moment Mstr generated in response to the steering of the front wheel 3f becomes a positive trail length. It will be in the opposite direction of a normal two-wheeled vehicle.

Even if the trail length t is longer than astr * tan (θcf)), if the trail length t is a negative value, the trail length t becomes a value close to astr * tan (θcf)). The steering moment Mstr generated according to the steering of the front wheel 3f is very small (close to zero).

On the other hand, as described in Patent Documents 1 and 2, when the traveling speed of the two-wheeled vehicle 1 is relatively low (including the stopped state), the posture of the vehicle body 2 in the roll direction (roll) is controlled by steering control of the front wheels 3f. In controlling the inclination angle of the direction, the trail length t is preferably set to a negative value, for example.

In this way, when the trail length t is set to a negative value in order to control the posture of the vehicle body 2 in the roll direction, as described above, the steering moment Mstr corresponding to the steering of the front wheels 3f around the steering axis Csf. Or a steering moment Mstr having a polarity (direction) opposite to the polarity (reverse direction) of the front wheel steering angle δf is generated. As a result, the torque acting from the front wheel 3f side on the steering operation part such as a handle for the driver to steer the front wheel 3f is also the same as the steering moment Mstr.

Therefore, in the present embodiment, even when the trail length t is set to a negative value, the steering moment having the same polarity as the front wheel steering angle δf (in the same direction) as in the case where the trail length t is set to a positive value. Steering control of the front wheels 3f is executed so that Mstr is generated around the steering axis Csf (and thus the same torque as the steering moment Mstr is applied to the steering operation unit such as a steering wheel).

(Description of Embodiment)
Based on the matter described above, an embodiment of the present invention will be described in detail. In the description of the present embodiment, the same reference numerals as those in FIG. 1 are used for the components having the same functions as those of the two-wheeled vehicle 1 shown in FIG.

Referring to FIG. 4, the moving body 1 </ b> A of the present embodiment is a two-wheeled vehicle including a vehicle body 2, and front wheels 3 f and rear wheels 3 r arranged at intervals in the front-rear direction of the vehicle body 2. Hereinafter, the moving body 1A is referred to as a motorcycle 1A.

The seat 6 on which the driver sits is mounted on the upper surface of the vehicle body 2. The front part of the vehicle body 2 includes a front wheel support mechanism 4 that pivotally supports the front wheel 3f, a steering handle 7 that can be gripped by a driver seated on the seat 6, and an actuator 8 that generates a driving force for steering the front wheel 3f (hereinafter referred to as the steering wheel 7). , Sometimes referred to as a steering actuator 8).

The front wheel support mechanism 4 includes a trail length variable mechanism 9 which is a mechanism for changing the trail length t of the front wheel 3f, and a front fork 10 including a suspension mechanism such as a damper. The front wheel 3f is pivotally supported via a bearing or the like at the lower end of the front fork 10 so as to be able to rotate around its axle centerline.

The trail length variable mechanism 9 is configured as shown in FIGS. 5 and 6, for example. Specifically, the trail length variable mechanism 9 includes a frame-like steering rotating portion 12 rotatably supported by a head pipe 11 provided at the front end portion of the vehicle body 2, and a hinge mechanism 13 provided to the steering rotating portion 12. A frame-like rocking portion 14 that is assembled so as to be freely rockable via an actuator 15 and an actuator 15 that generates a driving force for rocking the rocking portion 14 (hereinafter, referred to as a trail length changing actuator 15). And a crank mechanism 16 that swings the swinging portion 14 with respect to the steering rotating portion 12 by the driving force of the actuator 15.

The axis of the head pipe 11 is the steering axis Csf of the front wheel 3f, and the head pipe 11 is fixed to the front end of the vehicle body 2 so that the steering axis Csf tilts backward. The steering rotation unit 12 is arranged so that the head pipe 11 is sandwiched between the upper end portion and the lower end portion thereof, and the head pipe so that it can rotate around the steering axis Csf with respect to the head pipe 11. 11 is fitted.

The oscillating portion 14 is disposed on the front side of the steering rotation portion 12, and an upper end portion thereof is connected to an upper end portion of the steering rotation portion 12 by a hinge mechanism 13. The front fork 10 extends downward from the lower end of the swinging portion 14.

As a result, the swinging portion 14 can rotate integrally with the steering rotating portion 12 around the steering axis Csf together with the front fork 10 and the front wheel 3f. It can swing around the rotation axis. In this case, the rotational axis of the hinge mechanism 13 (the center axis of the swing of the swinging portion 14) extends in the left-right direction (vehicle width direction) of the vehicle body 2. Accordingly, the swinging portion 14 swings in the pitch direction with respect to the steering rotating portion 12 in the reference posture state of the two-wheeled vehicle 1A.

The reference posture state of the two-wheeled vehicle 1A is a straight traveling posture (the axle centerline of the front wheel 3f is parallel to the axle centerline of the rear wheel 3r) on the horizontal ground surface 110, similarly to the reference posture state of the two-wheeled vehicle 1 of FIG. Standing posture).

The trail length changing actuator 15 is constituted by an electric motor mounted on the swinging portion 14, and outputs a rotational driving force via a speed reducer 17. More specifically, in the example of the present embodiment, a trail length changing actuator 15 and a speed reducer 17 are arranged at an upper portion and a lower portion inside the swinging portion 14, respectively. It is fixed to the swing part 14. Note that the speed reducer 17 may have an arbitrary structure such as a harmonic drive (registered trademark) or a plurality of gears.

The output shaft of the trail length changing actuator 15 is connected to the input shaft of the speed reducer 17 via a power transmission mechanism 18 constituted by a pulley / belt mechanism or the like. As a result, the rotational driving force generated by the trail length changing actuator 15 is input from the output shaft of the actuator 15 to the speed reducer 17 via the power transmission mechanism 18 and further output from the speed reducer 17. ing.

In this embodiment, the trail length changing actuator 15 includes an electric lock mechanism 15a that holds its output shaft in a non-rotatable state. The lock mechanism 15a can be constituted by a friction brake mechanism or the like.

The power transmission mechanism 18 may have a function as a speed reducer, and the speed reducer 17 may be omitted. Alternatively, by connecting the output shaft of the trail length changing actuator 15 and the input shaft of the speed reducer 17 coaxially, the rotational driving force of the trail length changing actuator 15 is directly input to the speed reducer 17. May be. Further, the trail length changing actuator 15 may be constituted by a hydraulic actuator.

The crank mechanism 16 includes a pair of crank arms 19 a and 19 b provided to rotate integrally with the output shaft of the speed reducer 17, and a connecting rod 20 that connects the crank arms 19 a and 19 b to the steering rotation unit 12. .

The pair of crank arms 19a and 19b are arranged inside the swinging portion 14 so as to face each other with a space in the axial direction of the output shaft of the speed reducer 17. One crank arm 19a has a portion near one end fixed to the output shaft of the speed reducer 17 and is rotatable with the output shaft.

Further, the other crank arm 19b is provided with a support shaft 21 fixed coaxially with the output shaft of the speed reducer 17 at a portion near one end thereof. The crank arm 19b is pivotally supported by the bearing portion 22 fixed to the swinging portion 14 via the support shaft 21 so as to be rotatable.

These crank arms 19a and 19b are connected to each other via an eccentric shaft 23 whose other end is eccentric from the axis of the output shaft of the speed reducer 17 (= the rotational axis of the crank arms 19a and 19b). One end of the connecting rod 20 is rotatably supported on the eccentric shaft 23 between the crank arms 19a and 19b. The other end of the connecting rod 20 is rotatably supported by a support shaft 24 that is fixed to the steering rotation unit 12 inside the steering rotation unit 12. The axial center direction of the support shaft 24 is parallel to the axial center of the eccentric shaft 23.

The trail length variable mechanism 9 is configured as described above. For this reason, the front wheel 3f is steered around the steering axis Csf by rotating the steering rotating part 12 and the swinging part 14 of the variable trail length mechanism 9 around the steering axis Csf.

Further, by rotating the crank arms 19 a and 19 b around the axis of the output shaft of the speed reducer 17 by the rotational driving force of the trail length changing actuator 15, the swinging portion 14 is hinged with respect to the steering rotating portion 12. It swings around a rotation axis of the mechanism 13 within a predetermined angle range. As the swinging portion 14 swings, the front wheel 3 f also swings around the rotational axis of the hinge mechanism 13. For this reason, the front wheel 3 f is displaced in the front-rear direction with respect to the vehicle body 2. As a result, the contact point of the front wheel 3 f is displaced in the front-rear direction within a predetermined range with respect to the intersection of the steering axis Csf and the contact surface 110. As a result, the trail length t changes within a predetermined range.

In this case, the front wheel 3f can be displaced in the front-rear direction between the state indicated by a solid line in FIG. 4 and the state indicated by a two-dot chain line, for example, as the swinging portion 14 swings. The displacement state of the front wheel 3f indicated by a solid line in FIG. 4 is a state where the trail length t is a negative value tn, and the displacement state of the front wheel 3f indicated by a two-dot chain line is a state where the trail length t is a positive value tp. It is. Therefore, the trail length t can be changed within a range between the lower limit value tn (<0) and the upper limit value tp (> 0). Hereinafter, the lower limit value tn is referred to as a lower limit trail length tn, and the upper limit value tp is referred to as an upper limit trail length tp.

In the present embodiment, the lock mechanism 15a mechanically holds the output shaft of the trail length changing actuator 15 in a non-rotatable state, so that the swinging portion 14 cannot swing relative to the steering rotating portion 12. Retained. As a result, the trail length t can be mechanically fixedly held (locked) without controlling the driving force of the trail length changing actuator 15.

In this embodiment, the trail length changing actuator 15 is provided with the lock mechanism 15a. However, instead of the lock mechanism 15a, for example, the output shaft of the speed reducer 17 or the crank arms 19a, 19b is held unrotatable. You may make it equip the output side of the reduction gear 17 with the locking mechanism to perform.

The steering actuator 8 generates a rotational driving force for rotating the front wheel 3f around the steering axis Csf as a driving force for steering the front wheel 3f. In this embodiment, the steering actuator 8 is constituted by an electric motor. The housing of the steering actuator 8 is fixed to the vehicle body 2. The output shaft of the steering actuator 8 is connected to the lower end portion of the steering rotation unit 12 via a power transmission mechanism 25 constituted by a pulley / belt mechanism or the like. As a result, a rotational driving force around the steering axis Csf is applied from the steering actuator 8 to the steering rotation unit 12 via the power transmission mechanism 25. The power transmission mechanism 25 also has a deceleration function.

By applying a rotational driving force from the steering actuator 8 to the steering rotation unit 12, the front wheel support mechanism 4 including the trail length variable mechanism 9 and the front fork 10 is rotationally driven together with the front wheels 3f around the steering axis Csf. Thereby, the front wheel 3 f is steered by the rotational driving force of the steering actuator 8. Further, the torque generated around the steering axis Csf can be adjusted by adjusting the rotational driving force of the steering actuator 8.

Further, in the present embodiment, the power transmission mechanism 25 incorporates a steering clutch 8 a that is a clutch mechanism for appropriately interrupting power transmission between the steering actuator 8 and the steering rotation unit 12. The steering clutch 8a is configured by, for example, an electromagnetic clutch. The steering actuator 8 is not limited to an electric motor, and may be constituted by, for example, a hydraulic actuator.

The steering handle 7 has a function as a steering operation unit for the driver to perform the steering operation of the front wheels 3f, and is assembled to the steering rotation unit 12 of the trail length variable mechanism 9. Specifically, the steering handle 7 is fixed to the upper end portion of the steering rotation unit 12 via a support column 26 so as to rotate about the steering axis Csf integrally with the steering rotation unit 12. As a result, the driver can perform the steering operation of the front wheel 3 f by rotating the steering handle 7. Although not shown in detail, the steering handle 7 is assembled with an accelerator grip, a brake lever, a direction indicator switch, and the like, as in a normal motorcycle handle.

An actuator 27 that rotates the front wheel 3f around its axle center line Cf is mounted on the axle of the front wheel 3f. The actuator 27 has a function as a prime mover that generates the propulsive force of the motorcycle 1A. In the present embodiment, the actuator 27 (hereinafter sometimes referred to as a travel actuator 27) is configured by an electric motor (an electric motor with a speed reducer).

The travel actuator 27 may be constituted by, for example, a hydraulic actuator instead of the electric motor. Alternatively, the travel actuator 27 may be constituted by an internal combustion engine. Alternatively, the traveling actuator 27 may be mounted on the vehicle body 2 at a position away from the axle of the front wheel 3f, and the traveling actuator 27 and the axle of the front wheel 3f may be connected by an appropriate power transmission device. Further, instead of the travel actuator 27, or in addition to the travel actuator 27, an actuator for rotationally driving the rear wheel 3r may be provided.

The rear wheel support mechanism 5 that rotatably supports the rear wheel 3r is assembled to the rear portion of the vehicle body 2. The rear wheel support mechanism 5 includes a swing arm 28 and a suspension mechanism 29 configured by a coil spring, a damper, and the like. As these mechanical structures, for example, the same structure as a rear wheel support mechanism of a normal motorcycle can be adopted.

The rear wheel 3r is pivotally supported at the end of the swing arm 28 (the end on the rear side of the vehicle body 2) via a bearing or the like so as to be able to rotate around the axle center line. The rear wheel 3r is a non-steered wheel.

In addition to the above-described mechanical configuration, the two-wheeled vehicle 1A is used for controlling the operation of the steering actuator 8, the steering clutch 8a, the trail length changing actuator 15, the lock mechanism 15a, and the traveling actuator 27, as shown in FIG. A control device 50 that executes control processing is provided.

Further, the two-wheeled vehicle 1A uses a vehicle body inclination detector 51 that detects the inclination angle φb of the vehicle body 2 in the roll direction and a front wheel steering angle δf as sensors for detecting various state quantities necessary for the control processing of the control device 50. A front wheel steering angle detector 52 for detecting, a trail length detector 53 for detecting the trail length, a front wheel rotational speed detector 54 for detecting the rotational speed (angular speed) of the front wheel 3f, and the rotational speed (angular speed) of the rear wheel 3r. And an accelerator operation detector 56 that detects an accelerator operation amount that is an operation amount (rotation amount) of the accelerator grip of the steering handle 7.

The vehicle body inclination detector 51 is constituted by an inertial sensor including, for example, an acceleration sensor and a gyro sensor (angular velocity sensor), and is assembled to the vehicle body 2. In this case, the control device 50 measures the tilt angle φb in the roll direction of the vehicle body 2 (more specifically, the tilt angle in the roll direction with respect to the vertical direction (gravity direction)) based on the output of the inertial sensor. As the measurement method, for example, a strap-down method or the like can be employed. Note that the vehicle body inclination detector 51 may include a processing unit (processor or the like) that performs a measurement process of the inclination angle φb of the vehicle body 2 in the roll direction.

The front wheel steering angle detector 52 includes, for example, a steering actuator 8 (electric motor), a power transmission mechanism 25, or a detector such as a rotary encoder or resolver assembled to the steering rotation unit 12. A detection signal corresponding to the rotation angle of the output shaft or steering rotation unit 12 is output.

The trail length detector 53 includes, for example, a trail length changing actuator 15 (electric motor) or a detector such as a rotary encoder or resolver assembled to the speed reducer 17, and the trail length changing actuator 15 or the speed reducer 17. A detection signal corresponding to the rotation angle of the output shaft is output.

Here, in the present embodiment, the trail length t is defined according to the swing amount of the swing portion 14 with respect to the steering rotation portion 12 of the trail length variable mechanism 9 (the rotation angle around the rotation axis of the hinge mechanism 13). . Further, the swing amount of the swing portion 14 is defined according to the rotation angle of the crank arms 19a and 19b. Further, the rotation angles of the crank arms 19 a and 19 b are defined according to the rotation angle of the output shaft of the trail length changing actuator 15.

Therefore, the trail length t can be detected from the output of the trail length detector 53 (detection signal corresponding to the rotation angle of the output shaft of the trail length changing actuator 15 or the speed reducer 17). The trail length detector 53 may be provided so as to be able to detect, for example, the swing amount of the swing portion 14.

The front wheel rotational speed detector 54 is constituted by, for example, a detector such as a rotary encoder or resolver assembled on the axle of the front wheel 3f, and outputs a detection signal corresponding to the rotational angle or rotational angular speed of the front wheel 3f.

The rear wheel rotational speed detector 55 is constituted by, for example, a detector such as a rotary encoder assembled to the axle of the rear wheel 3r, and outputs a detection signal corresponding to the rotational angle or rotational angular speed of the rear wheel 3r.

The accelerator operation detector 56 is constituted by detectors such as a rotary encoder and a potentiometer built in the steering handle 7, and outputs a detection signal corresponding to the rotation angle or the rotation angular velocity of the accelerator grip.

The control device 50 includes one or more electronic circuit units including a microcomputer, a memory, an interface circuit, and the like, and is assembled to the vehicle body 2. The outputs (detection signals) of the detectors 51 to 56 are input to the control device 50.

The function of the control device 50 will be further described with reference to FIGS. In the following description, the XYZ coordinate system is the same as in the case of the two-wheeled vehicle 1 in FIG. 1, the front-rear direction, the left-right direction (vehicle width direction), and the height direction (vertical direction) Are coordinate systems in which the X-axis direction, the Y-axis direction, and the Z-axis direction are used (see FIG. 3).

In the following description, the subscript “_act” attached to the reference symbol of the state quantity is used as a code indicating an actual value or an observed value (detected value or estimated value). The subscript “_cmd” is added to the target value.

Here, as described in Patent Documents 1 and 2, the dynamic behavior of the posture of the vehicle body 2 in the roll direction is shown above the ground surface 110 of the motorcycle 1A as shown in FIG. Inverted pendulum mass point 123 that can move in the lateral direction (Y-axis direction) according to the change in the tilt angle φb in the roll direction, and the ground contact surface 110 according to the steering of the front wheel 3f (in accordance with the change in the front wheel steering angle δf). It can be approximately expressed by a dynamic model of a two-mass system composed of a contact surface upper mass point 124 that can move in the horizontal direction (in the Y-axis direction).

In this case, the mass m1 of the inverted pendulum mass point 123, the mass m2 of the ground contact surface mass point 124, the height h ′ of the inverted pendulum mass point 123, the overall mass m of the motorcycle 1A, the height h of the overall center of gravity G of the motorcycle 1A, and The relationship between the overall inertia I (the moment of inertia around the axis in the X-axis direction passing through the overall center of gravity G) of the motorcycle 1A is expressed by the following equations (6a) to (6d).

m1 + m2 = m (6a)
m1 * c = m2 * h (6b)
m1 * c ² + m2 * h ² = I (6c)
c = h′−h (6d)

Note that the slope of the straight line connecting the inverted pendulum mass point 123 and the ground contact surface mass point 124 coincides with the tilt angle φb of the vehicle body 2 in the roll direction.

The control device 50 according to the present embodiment basically has a control process (inverted pendulum mass point 123) based on the above-described two-mass system dynamic model, as described in Patent Documents 1 and 2. The steering control of the front wheel 3f is performed by a control process in consideration of the motion state of the front wheel 3f. However, in the present embodiment, the control device 50 performs the steering control so that the required steering moment Mstr can be generated.

As shown in FIG. 7, the control device 50 has, as main functions realized by the implemented hardware configuration and program (software configuration), the Y-axis direction of the inverted pendulum mass point 123 of the dynamic model (the vehicle body 2 Inverted pendulum mass lateral movement estimated value (hereinafter referred to as an inverted pendulum mass point lateral movement estimated value Pb_diff_y_act) is calculated as an inverted pendulum mass lateral movement Pb_diff_y actual value Pb_diff_y The estimated value of the actual value Vby_act of the inverted pendulum mass point lateral velocity Vby which is the translational velocity of the unit 31 and the inverted pendulum mass point 123 in the Y-axis direction (left and right direction of the vehicle body 2) (hereinafter referred to as the inverted pendulum mass point lateral velocity estimated value Vby_act) ) And an estimated value of the actual value Vox_act of the vehicle speed Vox (traveling speed) of the two-wheeled vehicle 1A (hereinafter referred to as a vehicle speed estimated value Vox_act). Estimated vehicle speed calculation unit 33, target value Pb_diff_y_cmd (hereinafter referred to as target inverted pendulum mass point lateral movement amount Pb_diff_y_cmd) and inverted pendulum mass point lateral speed Vby_cmd (hereinafter referred to as target inverted) A target posture state determination unit 34 that determines a pendulum mass point lateral velocity Vby_cmd), a control gain determination unit 35 that determines values of a plurality of gains K1, K2, K3, K4, and K5 for posture control of the vehicle body 2; A target vehicle speed determination unit 36 that determines a target value Vox_cmd (hereinafter referred to as a target vehicle speed Vox_cmd) of the vehicle speed Vox of the motorcycle 1A, and a target trail length determination that determines a target value t_cmd (hereinafter referred to as a target trail length t_cmd) of the trail length t. And a standard steering moment determination unit 38 that determines a standard value Mstr_nml (hereinafter referred to as standard steering moment Mstr_nml) of the steering moment Mstr.

Furthermore, the control device 50 executes a calculation process for attitude control of the vehicle body 2 to thereby obtain a target value δf_cmd of the front wheel steering angle δf (hereinafter referred to as a target front wheel steering angle δf_cmd) and the time of the front wheel steering angle δf. The target value δf_dot_cmd (hereinafter referred to as target front wheel steering angular velocity δf_dot_cmd) of the front wheel steering angular velocity δf_dot that is the rate of change and the target value δf_dot2_cmd (hereinafter referred to as target front wheel steering) of the front wheel steering angular acceleration δf_dot2 that is the temporal change rate of the front wheel steering angular velocity δf_dot A posture control calculation unit 39 that determines an angular acceleration δf_dot2_cmd).

Further, in the present embodiment, the steering control of the front wheels 3f via the steering actuator 8 (and consequently the posture of the vehicle body 2 in the roll direction) is performed by operating a predetermined mode setting switch (not shown) provided in the motorcycle 1A. The driver can selectively set the control device 50 as to whether or not to execute the control.

Then, the control device 50 performs the processing of each functional unit shown in FIG. 7 at a predetermined control processing cycle when the two-wheeled vehicle 1A stops and travels in a state in which the mode for performing the steering control of the front wheels 3f is selected. Run sequentially.

The control device 50 controls the steering actuator 8 in accordance with the target front wheel steering angle δf_cmd, the target front wheel steering angular velocity δf_dot_cmd, and the target front wheel steering angular acceleration δf_dot2_cmd determined by the attitude control calculation unit 39.

Further, the control device 50 controls the trail length changing actuator 15 according to the target trail length t_cmd determined by the target trail length determination unit 37. Further, the control device 50 controls the travel actuator 27 in accordance with the target vehicle speed Vox_cmd determined by the target vehicle speed determination unit 36.

Hereinafter, details of the control processing of the control device 50 (control processing in a state where the mode for performing the steering control of the front wheels 3f is selected) will be described. In this control process, the value of the parameter h ′ related to the above-described two-mass dynamic model and the values of the parameters θcf, Lf, and Lr related to the specifications of the motorcycle 1 are used. The values of these parameters h ′, θcf, Lf, Lr are predetermined set values (fixed values), and are stored and held in the memory of the control device 50.

Further, among the control processing of the control device 50, the processing of each functional unit other than the standard steering moment determination unit 38, the control gain determination unit 35, and the attitude control calculation unit 39 is described in Patent Documents 1 and 2 in this embodiment. It is the same as that described in. Therefore, the description of the processing of each functional unit other than the standard steering moment determination unit 38, the control gain determination unit 35, and the attitude control calculation unit 39 of the control device 50 is only a brief description.

The control device 60 includes a target vehicle speed determining unit 36, a standard steering moment determining unit 38, a vehicle speed estimated value calculating unit 33, a target posture state determining unit 34, and an inverted pendulum mass point lateral movement estimated value calculating unit 31 in each control processing cycle. Processing is performed as described below.

The detected value of the accelerator operation amount indicated by the output of the accelerator operation detector 56 is input to the target vehicle speed determination unit 36. Then, the target vehicle speed determination unit 36 determines the target vehicle speed Vox_cmd from the detected value of the accelerator operation amount using a map or an arithmetic expression created in advance. In this case, the target vehicle speed Vox_cmd is determined so as to increase as the accelerator operation amount increases within a predetermined maximum value or less.

Note that when the brake operation of the motorcycle 1A is performed, the target vehicle speed Vox_cmd depends on the detected value of the brake operation amount or both of the detected value of the brake operation amount and the detected value of the accelerator operation amount. It may be determined by a map or an arithmetic expression.

The vehicle speed estimated value calculation unit 33 is identified from the detected value of the front wheel steering angle δf_act indicated by the output of the front wheel steering angle detector 52 and the detected value of the rotational angular velocity of the front wheel 3f indicated by the output of the front wheel rotational speed detector 54. The estimated value of the rotational movement speed Vf_act of the front wheel 3f (specifically, the movement speed calculated by multiplying the detected value of the rotational angular speed of the front wheel 3f by the predetermined effective rotation radius of the front wheel 3f) is input.

Then, the vehicle speed estimated value calculation unit 33 calculates the vehicle speed estimated value Vox_act from the input detection value of the front wheel steering angle δf_act and the estimated value of the rotational movement speed Vf_act of the front wheel 3f by the following equation (7), for example. .

Vox_act = Vf_act * cos (δf_act * cos (θcf)) (7)

The vehicle speed estimated value Vox_act calculated in this way corresponds to the X-axis direction component of the estimated value of the rotational movement speed Vf_act of the front wheel 3f. The estimated value of the rotational movement speed of the rear wheel 3r specified from the detected value of the rotational angular speed of the rear wheel 3r indicated by the output of the rear wheel rotational speed detector 55 (specifically, the detected value of the rotational angular speed of the rear wheel 3r). May be obtained as the vehicle speed estimated value Vox_act).

The detected value of the front wheel steering angle δf_act is input to the standard steering moment determination unit 38. Then, the standard steering moment determination unit 38 determines the standard steering moment Mstr_nml from the input detected value of the front wheel steering angle δf_act based on correlation data such as a map or a calculation formula created in advance. The correlation data is correlation data representing the relationship between the front wheel steering angle δf and the standard steering moment Mstr_nml, and is stored and held in the control device 50 in advance.

In this case, the standard steering moment Mstr_nml determined on the basis of the correlation data is a standard positive trail length (for example, the trail length t_nml shown in FIG. 3). When the front wheel 3f is steered without operating the steering actuator 8 while maintaining the trail length (tnml), the steering moment Mstr generated according to the front wheel steering angle δf is matched or substantially matched. It is determined.

For example, when the trail length t in the equation (5) is matched with the standard trail length tnml, the relationship between the front wheel steering angle δf defined by the equation (5) and the steering moment Mstr is the correlation data. And the standard steering moment Mstr_nml corresponding to the front wheel steering angle δf is determined based on the correlation data.

As the standard trail length tnml, for example, a trail length similar to that of a normal motorcycle can be adopted. In this embodiment, the upper limit trail length tp is the standard trail length tnml.

Supplementally, in the actual vehicle of the two-wheeled vehicle 1A in which the trail length t_act is maintained at the standard trail length tnml, the relationship between the steering moment Mstr generated according to the steering of the front wheel 3f and the front wheel steering angle δf is measured. The correlation data for determining the standard steering moment Mstr_nml may be created based on the actually measured data. Further, it is more desirable to determine the standard steering moment Mstr_nml in consideration of the influence of the tilt angle φb in the roll direction of the vehicle body 2 caused by disturbance. For example, the value (reference value) of the standard steering moment Mstr_nm obtained based on the correlation data is set according to the inverted pendulum mass point lateral movement estimated value Pb_diff_y_act calculated as described later (or the tilt angle of the vehicle body 2 in the roll direction). It is more desirable to determine the standard steering moment Mstr_nm by correcting (according to the detected value of φb_act).

The target posture state determination unit 34 obtains a target inverted pendulum mass point lateral movement amount Pb_diff_y_cmd that is a target value of the inverted pendulum mass point lateral movement amount Pb_diff_y and a target inverted pendulum mass point lateral velocity Vby_cmd that is a target value of the inverted pendulum mass point lateral velocity Vby. decide. In the present embodiment, the target posture state determination unit 34 sets both Pb_diff_y_cmd and Vby_cmd to zero as an example.

The inverted pendulum mass point lateral movement estimated value calculation unit 31 includes a detected value of the inclination angle φb in the roll direction of the vehicle body 2 indicated by the output of the vehicle body inclination detector 51 and a front wheel indicated by the output of the front wheel steering angle detector 52. The detected value of the steering angle δf_act is input. Then, the inverted pendulum mass point lateral movement estimated value calculation unit 31 uses the input detected value of the inclination angle φb and the detected value of the front wheel steering angle δf_act, according to the following equation (8), according to the following equation (8). Estimated value Pb_diff_y_act is calculated.

Pb_diff_y_act = φb_act * (− h ′) + Plfy (δf_act) (8)

Here, Plfy (δf_act) on the right side of Expression (8) is a function value corresponding to the detected value of the front wheel steering angle δf_act of the function Plfy (δf) of the front wheel steering angle δf. The function Plfy (δf) is a nonlinear function having a characteristic that the function value decreases as the front wheel steering angle δf increases (increases from a negative value to a positive value).

The control device 50 further executes the processes of the inverted pendulum mass point lateral velocity estimated value calculation unit 32, the control gain determination unit 35, and the target trail length determination unit 37 in each control processing cycle as described below.

The inverted pendulum mass point lateral velocity estimated value calculation unit 32 includes the inverted pendulum mass point lateral movement estimated value calculation unit 31 calculated by the inverted pendulum mass point lateral movement estimated value Pb_diff_y_act, the detected value of the front wheel steering angle δf_act, and the front wheel 3f. And an estimated value of the rotational movement speed Vf_act. Then, the inverted pendulum mass point lateral speed estimated value calculation unit 32 uses the input inverted pendulum mass point lateral movement estimated value Pb_diff_y_act, the detected value of the front wheel steering angle δf_act and the estimated value of the rotational movement speed Vf_act as follows: ) To calculate an estimated pendulum mass point lateral velocity estimated value Vby_act.

Vby_act
= Pb_diff_y_dot_act + Vf_act * sin (δf_act * cos (θcf)) * (Lr / L)
...... (9)

Note that Pb_diff_y_dot_act in the first term on the right side of Equation (9) is a temporal change rate (change amount per unit time) of the inverted pendulum mass point lateral movement estimated value Pb_diff_y_act.

The control gain determination unit 35 receives the vehicle speed estimation value Vox_act calculated by the vehicle speed estimation value calculation unit 33 and the detected value of the trail length t_act indicated by the output of the trail length detector 53, and the previous control. The previous target front wheel steering angle δf_cmd_p, which is the target front wheel steering angle δf_cmd calculated by the attitude control calculation unit 39 in the processing cycle, is input via the delay element 40.

The previous target front wheel steering angle δf_cmd_p has a meaning as a pseudo estimated value of the actual steering angle δf_act of the front wheel 3f at the current time. Therefore, instead of δf_cmd_p, the detected value of the front wheel steering angle δf_act at the current time indicated by the output of the front wheel steering angle detector 52 may be input to the control gain determination unit 35.

Then, the control gain determination unit 35 uses gains K1, K2, K3, K4, and K5 described later in the processing of the attitude control calculation unit 39, the input vehicle speed estimation value Vox_act, the detected value of the trail length t_act, and the previous target front wheel. It is determined according to the steering angle δf_cmd_p (or the detected value of the front wheel steering angle δf_act). A specific determination process for the gains K1, K2, K3, K4, and K5 will be described later.

The vehicle speed estimated value Vox_act calculated by the vehicle speed estimated value calculating unit 33 is input to the target trail length determining unit 37. Then, the target trail length determination unit 37 determines the target trail length t_cmd according to the input vehicle speed estimation value Vox_act. In this case, in the present embodiment, the target trail length t_cmd is determined as one of the upper limit trail length tp and the lower limit trail length tn according to the vehicle speed estimation value Vox_act, for example, as shown in FIG.

Specifically, when the vehicle speed estimation value Vox_act is zero, the target trail length t_cmd is determined to be the lower limit trail length tn (<0). In the state where t_cmd = tn, the target trail length t_cmd is maintained at the lower limit trail length tn until the vehicle speed estimation value Vox_act increases to a value exceeding a predetermined first predetermined value Vox1.

When the estimated vehicle speed value Vox_act exceeds the first predetermined value Vox1, the target trail length t_cmd is switched from the lower limit trail length tn to the upper limit trail length tp (> 0). In this embodiment, the upper limit trail length tp is the standard trail length t_nml.

Thereafter, in a state where t_cmd = tp, the target trail length t_cmd is set to the upper limit trail length tp (> 0) until the estimated vehicle speed value Vox_act falls to a value that falls below a predetermined second predetermined value Vox2. Maintained. In this case, the second predetermined value Vox2 is set to a speed smaller than the first predetermined value Vox1. When the estimated vehicle speed value Vox_act falls below the second predetermined value Vox2, the target trail length t_cmd is returned from the upper limit trail length tp to the lower limit trail length tn.

As described above, the target trail length t_cmd is basically set to the lower limit trail length tn (<0) when the actual vehicle speed Vox_act is a low speed vehicle speed (including when the vehicle is stopped). When the vehicle speed Vox_act is the vehicle speed on the high speed side, the upper limit trail length tp (> 0) is set. In this case, t_cmd is determined so as to have a hysteresis characteristic with respect to a change in Vox_act.

Supplementally, the target trail length t_cmd may be determined so as to continuously change with respect to the vehicle speed Vox_act. For example, the target trail length t_cmd may be determined according to the vehicle speed Vox_act in the manner shown in FIG. In this example, t_cmd is kept constant at the lower limit trail length tn in the low speed side vehicle speed range below the predetermined vehicle speed Vox3, and t_cmd is the upper limit trail length tp in the high speed side vehicle speed range above the predetermined vehicle speed Vox4 higher than Vox3. At a constant. Then, t_cmd is monotonously increased as Vox_act increases in the vehicle speed range between Vox3 and Vox4.

The control device 50 further executes the processing of the attitude control calculation unit 39 as described below in each control processing cycle. The posture control calculation unit 39 calculates the target inverted pendulum mass lateral movement amount Pb_diff_y_cmd and the target inverted pendulum mass lateral velocity Vby_cmd determined by the target posture state determination unit 34 and the inverted pendulum mass point lateral movement estimated value calculation unit 31. The inverted pendulum mass point lateral movement estimated value Pb_diff_y_act, the inverted pendulum mass point lateral velocity estimated value Vby_act calculated by the inverted pendulum mass point lateral velocity estimated value calculation unit 32, and the gains K1, K2, K3, K4, K5 and the standard steering moment Mstr determined by the standard steering moment determination unit 38 are input.

Then, the attitude control calculation unit 39 executes the processing shown in the block diagram of FIG. 12 using the above input values, thereby achieving the target front wheel steering angle δf_cmd, the target front wheel steering angular velocity δf_dot_cmd, and the target front wheel steering angle. The acceleration δf_dot2_cmd is determined.

In FIG. 12, a processing unit 39-1 is a processing unit that obtains a deviation between the input Pb_diff_y_cmd and Pb_diff_y_act, and a processing unit 39-2 is a processing unit that multiplies the output of the processing unit 39-1 by a gain K1. -3 is a processing unit for obtaining a deviation between the input Vby_cmd and Vby_act, the processing unit 39-4 is a processing unit that multiplies the output of the processing unit 39-3 by a gain K2, and the processing unit 39-5 is the previous control. The processing unit 39-6 that multiplies the previous target front wheel steering angle δf_cmd_p, which is the value of the target front wheel steering angle δf_cmd in the processing cycle, by the gain K3, and the processing unit 39-6 has the value of the target front wheel steering angular velocity δf_dot_cmd in the previous control processing cycle. The processing unit 39-7 that multiplies the previous target front wheel steering angular velocity δf_dot_cmd_p by the gain K4, the processing unit 39-7 multiplies the input standard steering moment Mstr by the gain K5, and the processing unit 39-8 includes the processing units 39-2 and 39. -4,39- Each output of the adding together the value of (-1) times the respective outputs of the processing unit 39-5,39-6, represent processing unit for calculating a target front-wheel steering angle acceleration Derutaefu_dot2_cmd.

The processing unit 39-9 integrates the output of the processing unit 39-8 to obtain the target front wheel steering angular velocity δf_dot_cmd, and the processing unit 39-10 processes the processing unit 39-9 in the previous control processing cycle. Element that outputs the output (ie, the previous target front wheel steering angular velocity δf_dot_cmd_p) to the processing unit 39-6, the processing unit 39-11 obtains the target front wheel steering angle δf_cmd by integrating the output of the processing unit 39-9. The processing unit, the processing unit 39-12 represents a delay element that outputs the output of the processing unit 39-11 in the previous control processing cycle (that is, the previous target front wheel steering angle δf_cmd_p) to the processing unit 39-5.

Therefore, in the present embodiment, the attitude control calculation unit 39 calculates the target front wheel steering angular acceleration δf_dot2_cmd by the following equation (10).

δf_dot2_cmd = K1 * (Pb_diff_y_cmd−Pb_diff_y_act)
+ K2 * (Vby_cmd-Vby_act)
-K3 * δf_cmd_p-K4 * δf_dot_cmd_p) + K5 * Mstr_nml
...... (10)

In this equation (10), K1 * (Pb_diff_y_cmd−Pb_diff_y_act) is a feedback manipulated variable having a function to bring the deviation (Pb_diff_y_cmd−Pb_diff_y_act) close to “0”, and K2 * (Vby_cmd−Vby_act) is a deviation (Vby_cmd−Vby_act). Is a feedback manipulated variable having a function of bringing δf closer to “0”, −K3 * δf_cmd_p is a feedback manipulated variable having a function of bringing δf_cmd closer to “0”, and −K4 * δf_dot_cmd_p is a feedback having a function of bringing δf_dot_cmd closer to “0” The operation amount, K5 * Mstr_nml, is a feedforward operation amount having a function of bringing the steering moment Mstr_act generated by the steering control of the front wheel 3f according to δf_dot2_cmd, δf_dot_cmd, and δf_cmd closer to the standard steering moment Mstr_nml.

Then, the attitude control calculation unit 39 determines the target front wheel steering angular velocity δf_dot_cmd by integrating δf_dot2_cmd determined by the above equation (10). Further, the attitude control calculation unit 39 determines the target front wheel steering angle δf_cmd by integrating the δf_dot_cmd.

Note that δf_cmd_p and δf_dot_cmd_p used in the calculation of Expression (10) have meanings as pseudo estimated values of the actual steering angle and steering angular velocity of the front wheel 3f at the current time, respectively. Therefore, the detected value of the front wheel steering angle Δf_act at the current time may be used instead of Δf_cmd_p. Further, instead of Δf_dot_cmd_p, the detected value of the front wheel steering angular velocity Δf_dot_act at the current time may be used.

The gains K1 to K5 used in the processing of the attitude control calculation unit 39 are determined by the control gain determination unit 35. In this case, the control gain determination unit 35 sets the target values of the gains K1 to K5, the estimated vehicle speed Vox_act, the previous target front wheel steering angle δf_cmd_p (or the detected value of the front wheel steering angle δf_act at the current time), the trail In accordance with the detected value of the length t_act, it is determined to change with a tendency as shown in the graphs of FIGS. 13A to 13C.

In this case, the target values of the gains K1 to K5 are determined so as to decrease (approach to zero) as the vehicle speed Vox (vehicle speed estimated value Vox_act) increases. In particular, at the vehicle speed Vox in the high speed range (vehicle speed higher than the predetermined vehicle speed Vox5 in FIG. 13A), the respective target values of the gains K1 to K5 are determined so as to coincide with or substantially coincide with zero.

The target values of the gains K1 to K4 among the gains K1 to K5 are, for example, the front wheel steering angle δf (the detected value of the previous front wheel steering angle δf_cmd_p or the front wheel steering angle δf_act), as shown in the graph of FIG. 13B, for example. As the size (absolute value) increases, it is determined with a tendency to decrease to zero.

The target values of the gains K1 to K4 among the gains K1 to K5 are such that, for example, as shown in the graph of FIG. 13C, the trail length t (detected value of the trail length t_act) is positive from the negative value. As the value increases, it tends to increase. Note that the processing for determining the target values of the gains K1 to K5 as described above is performed based on, for example, a map or an arithmetic expression created in advance.

Then, the control gain determination unit 35 gradually converges each value of the gains K1 to K5 used in the calculation process of the equation (10) to the target value determined as described above (for example, response characteristic of first-order delay) To converge). The attitude control calculation unit 39 uses the values of the gains K1 to K5 determined as described above to execute the calculation process of the above equation (10), thereby achieving the target front wheel steering angular acceleration δf_dot2_cmd, the target front wheel steering angular velocity δf_dot_cmd, and the target A front wheel steering angle δf_cmd is calculated. The gain K5 multiplied by the standard steering moment Mstr is preferably determined so as to follow the target value at a slower response speed than the other gains K1 to K5 used for the processing for controlling the posture of the vehicle body 2.

Next, the operation control of the steering actuator 8, the trail length changing actuator 15, and the traveling actuator 27 by the control device 50 will be described. The control device 50 controls the operation of the travel actuator 27 according to the target vehicle speed Vox_cmd determined by the target vehicle speed determination unit 36 and the estimated vehicle speed Vox_act calculated by the estimated vehicle speed calculation unit 33. For example, the control device 50 controls the travel actuator 27 using a feedback control law so that the estimated vehicle speed Vox_act follows the target vehicle speed Vox_cmd.

Note that, for example, the target rotational speed of the travel actuator 27 may be determined from the target vehicle speed Vox_cmd without using the vehicle speed estimated value Vox_act, and the travel actuator 27 may be controlled according to the target rotational speed.

Also, for example, it is possible to determine a target driving force to be output from the traveling actuator 27 according to the detected value of the accelerator operation amount, and to control the traveling actuator 27 according to the target driving force. In this case, the target vehicle speed determination unit 36 can be omitted.

In addition, the control device 50 controls the operation of the trail length changing actuator 15 according to the target trail length t_cmd determined by the target trail length determination unit 37. Specifically, when the target trail length t_cmd is switched from the lower limit trail length tn to the upper limit trail length tp (standard trail length t_nml), the control device 50 operates the lock mechanism 15a in the off state ( In the state in which the trail length t is unlocked by the lock mechanism 15a), the trail length t_act is from tn to tp within a predetermined time width Tacc, as exemplified by the broken line graph in the lower part of FIG. The trail length changing actuator 15 is controlled so as to change monotonously. In this case, the change pattern of the trail length t_act from tn to tp is not limited to a linear pattern, and various patterns can be adopted.

In this embodiment, when the target trail length t_cmd is set to the upper limit trail length tp and the detected value of the trail length t_act reaches a state that matches the upper limit trail length tp (= t_cmd) (t_cmd = t_act = Tp), the control device 50 locks the trail length t_act to the upper limit trail length tp by operating the lock mechanism 15a in the on state, and turns off the trail length changing actuator 15 (energization cut-off state). ).

Further, when the target trail length t_cmd is switched from the upper limit trail length tp to the lower limit trail length, the control device 50 operates the lock mechanism 15a in the OFF state, and the broken line in the lower diagram of FIG. As illustrated in the graph, the trail length changing actuator 15 is controlled so that the trail length t_act changes monotonously from tp to tn within a predetermined time width Tdec. In this case, the change pattern of the trail length t_act from tp to tn is not limited to a linear pattern, and various patterns can be adopted.

The time widths Tacc and Tdec may be the same time width or different time widths. Further, when the trail length t_act changes from one of the lower limit trail length tn and the upper limit trail length tp to the other, the trail length changing actuator 15 may be operated with a constant driving force.

Supplementally, the target trail length is not limited to the case where the detected value of the trail length t_act reaches the state of the upper limit trail length tp (= t_cmd) in the state where the target trail length t_cmd is set to the upper limit trail length tp. Even when the detected value of the trail length t_act reaches the lower limit trail length tn (= t_cmd) in a state where the t_cmd is set to the lower limit trail length tn, the lock mechanism 15a is operated in the on state. At the same time, the trail length changing actuator 15 may be turned off (energized state).

Further, the control device 50 controls the operation of the steering actuator 8 according to the target front wheel steering angular acceleration δf_dot2_cmd, the target front wheel steering angular velocity δf_dot_cmd, and the target front wheel steering angle δf_cmd determined by the attitude control calculation unit 39.

For example, the control device 50 calculates the following equation (11) from δf_dot2_cmd, δf_dot_cmd, δf_cmd, a detected value of the front wheel steering angle δf_act, and a detected value of the front wheel steering angular velocity δf_dot_act as a temporal change rate of the front wheel steering angle δf_act. Thus, the current command value I_δf_cmd, which is the target value of the energization current of the steering actuator 8, is determined. Here, the steering actuator 8 is an electric motor.

I_δf_cmd = Kδf_p * (δf_cmd−δf_act)
+ Kδf_v * (δf_dot_cmd−δf_dot_act)
+ Kδf_a * δf_dot2_cmd (11)

Here, δf_act and δf_dot_act in Equation (11) are detection values indicated by the output of the front wheel steering angle detector 52, and Kδf_p, Kδf_v, and Kδf_a are gains of predetermined values, respectively.

The control device 50 controls the actual energization current of the steering actuator 8 to a current that matches the current command value I_δf_cmd by a current control unit (not shown) configured by a motor driver or the like. Thereby, the actual steering angle δf_act of the front wheel 3f is controlled to follow the target front wheel steering angle δf_cmd. The operation control method of the steering actuator 8 may be a method different from the above as long as the method can control the steering angle δf_act of the front wheel 3f to the target steering angle δf_cmd.

In the present embodiment, when the mode for performing the steering control of the front wheels 3f is selected, the control process of the control device 50 is executed as described above when the two-wheeled vehicle 1A stops and travels.

In the state where the mode for performing the steering control of the front wheel 3f is selected, the control device 50 operates the steering clutch 8a in an off state (a state in which power transmission from the steering actuator 8 to the steering rotation unit 12 is cut off). At the same time, the steering actuator 8 is turned off (energization cut-off state). Further, the control device 50 locks the trail length t_act to the upper limit trail length tp (= standard trail length t_nml) by the lock mechanism 15a.

According to the embodiment described above, in the calculation process (formula (10)) for determining the target front wheel steering angular acceleration δf_dot2_cmd by the attitude control calculation unit 39, the component (Mstr_nml) corresponding to the standard steering moment Mstr_nml is multiplied by the gain K5. Component) is added. The steering actuator 8 is controlled according to the target front wheel steering angular acceleration δf_dot2_cmd, the target front wheel steering angular velocity δf_dot_cmd and the target front wheel steering angle δf_cmd obtained by integrating the target front wheel steering angular acceleration δf_dot2_cmd.

For this reason, the steering actuator 8 operates so as to stabilize the posture of the vehicle body 2 in the roll direction, and applies a steering torque in the same direction as the standard steering moment Mstr_nml around the steering axis Csf to the steering handle 7. Operates to give regardless of the length t_act. In this case, since the standard steering moment Mstr_nml is determined according to the detected value of the front wheel steering angle δf_act, the steering torque applied to the steering handle 7 also corresponds to the actual front wheel steering angle δf_act. Become.

Therefore, the driver of the two-wheeled vehicle 1 </ b> A can use a trail having a positive trail length t_act even in a state where the trail length t_act is a negative trail length (in this embodiment, the vehicle speed estimated value Vox_act is a low speed vehicle speed). The steering handle 7 can be operated while receiving from the steering handle 7 a reaction force in the same direction as the long state.

Further, the target value of the gain K5 multiplied by the low-speed side vehicle speed Vox in which the standard steering moment trail length t_act is set to a negative trail length in the calculation process of the above equation (10) becomes smaller as the vehicle speed estimated value Vox_act increases. Therefore, the vehicle speed Vox on the low speed side where the trail length t_act is set to a negative trail length is included in the target front wheel steering angular acceleration δf_dot2_cmd than the vehicle speed Vox on the high speed side where the trail length t_act is set to a positive trail length. The component (= K5 * Mstr_nml) corresponding to the standard steering moment Mstr_nml is increased. As a result, it can suppress that the torque provided with respect to the steering handle 7 fluctuates according to the trail length t_act.

In the embodiment described above, the trail length variable mechanism may have a structure different from that illustrated in FIGS. 5 and 6. The trail length variable mechanism for changing the trail length of the front wheel 3f may have any structure as long as it can change the trail length of the front wheel 3f by an actuator.

For example, the trail length variable mechanism may be configured to move the front wheel 3f linearly in the front-rear direction with respect to the steering rotation unit 12 using a ball screw mechanism or the like. Further, the trail length variable mechanism may have a structure proposed in, for example, Japanese Patent Application Laid-Open No. 2014-184934 or US Pat. No. 9,302,730.

In the embodiment, the motorcycle 1A is exemplified as the moving body of the present invention. However, if the moving body of the present invention has a structure in which the vehicle body can be tilted in the roll direction in accordance with the weight shift of the driver, for example, the front wheel or the rear wheel is constituted by a plurality of wheels arranged in parallel in the vehicle width direction May be. Furthermore, the moving body of the present invention may have a structure in which, for example, the vehicle body and the front wheel can be inclined in the roll direction with respect to the rear wheel.

In the above embodiment, the roll of the vehicle body 2 is converged so as to converge to the target value of the state quantity using the lateral movement amount Pb_diff_y and the lateral speed Vby of the inverted pendulum mass point 123 as the state quantity indicating the tilt state of the vehicle body 2. The one that performs the attitude control of the direction is shown. However, for example, it is possible to control the posture of the vehicle body 2 in the roll direction using only the lateral movement amount Pb_diff_y of the inverted pendulum mass point 123 as the state quantity to be controlled. Alternatively, the tilt angle of the vehicle body 2 in the roll direction is used as the state quantity of the control target, or the tilt angle of the vehicle body 2 in the roll direction and the tilt angular velocity that is the temporal change rate are used as the state quantity of the control target. Thus, it is possible to control the posture of the vehicle body 2 in the roll direction.

Claims (5)

A front wheel and a rear wheel that are spaced apart from each other in the front-rear direction of the vehicle body, and the front wheel is a steerable wheel that can be steered around a steering axis, and the driver steers the front wheel A moving body having a steering operation section of
A front wheel support mechanism having a trail length variable mechanism for changing the trail length of the front wheel and configured to support the front wheel so as to be steerable around the steering axis;
A steering actuator for generating a driving force for steering the front wheels;
A trail length changing actuator for generating a driving force for changing the trail length of the front wheel;
A control device for controlling the steering actuator and the trail length changing actuator,
The movable body is configured to control the steering actuator so as to apply a steering torque in the same direction as a steering direction of the front wheels to the steering operation unit. The mobile body according to claim 1,
The trail length variable mechanism is configured to change the trail length of the front wheel between a positive upper limit trail length and a negative lower limit trail length,
The control device is configured to control the steering actuator so as to apply the steering torque to the steering operation unit at least in a state where the trail length of the front wheel is a negative trail length. A moving body characterized by. The mobile body according to claim 2,
The control device is configured to control the trail length changing actuator to change the trail length of the front wheel from a negative trail length to a positive trail length as the traveling speed of the moving body increases. And a moving body configured to control the steering actuator to weaken the steering torque as the traveling speed increases. The mobile body according to claim 1,
The control device is configured to determine the steering torque according to an observed value of a steering angle of the front wheels. The mobile body according to claim 4,
The control device stores and holds correlation data representing a relationship between a steering angle of the front wheel when the trail length of the front wheel is a predetermined positive value and a torque acting on the steering operation unit according to the steering angle. And the steering torque is determined based on the correlation data from the observed value of the steering angle of the front wheels.

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