JP2009073271A - vehicle - Google Patents

Abstract

[PROBLEMS] To fix a stable stop regardless of road gradient even on a slope by fixing an estimated value of a road gradient when an absolute value of a vehicle speed is equal to or less than a predetermined threshold value. Be able to maintain state.
A driving wheel 12 rotatably attached to a vehicle body, and a vehicle control device that controls a posture of the vehicle body by controlling a driving torque applied to the driving wheel 12, the vehicle control device comprising: The road surface gradient is estimated based on the posture of the vehicle body, and the estimated value of the road surface gradient is fixed when the absolute value of the speed of the vehicle 10 is a predetermined threshold value or less.
[Selection] Figure 1

Description

  The present invention relates to a vehicle using posture control of an inverted pendulum.

  Conventionally, a technique related to a vehicle using posture control of an inverted pendulum has been proposed. For example, a vehicle having two drive wheels arranged on the same axis and driving by detecting a change in the posture of the vehicle body due to the driver's movement of the center of gravity, while controlling the posture of the vehicle body with a single spherical drive wheel Techniques for moving vehicles and the like have been proposed (see, for example, Patent Document 1).

In this case, the balance and operation state of the vehicle body is detected by a sensor, and the vehicle is stopped or moved by controlling the operation of the rotating body.
JP 2004-129435 A

  However, the conventional vehicle cannot maintain a stopped state on a slope or travel stably. For example, to stop the vehicle on a slope, drive torque is applied to the drive wheels so that the vehicle does not move in the downward direction, or the center of gravity of the vehicle body is moved so as to cancel the vehicle body tilt torque by the action of gravity. In some cases, the posture of the vehicle body is controlled, but the vehicle body may vibrate due to fluctuations in the estimated value of the slope of the road surface. In general, vehicle occupants are more sensitive to vibrations in the stopped state than vibrations in the driving state, so when the vehicle body vibrates in the stopped state, the occupants feel very uncomfortable and the ride comfort is greatly reduced. To do.

  The present invention solves the problems of the conventional vehicle, and when the absolute value of the vehicle speed is not more than a predetermined threshold (threshold) value, the estimated value of the road surface gradient is fixed, so that even on a slope. An object of the present invention is to provide a vehicle that maintains a stable stop state regardless of the road surface gradient and has a comfortable ride.

  For this purpose, the vehicle of the present invention includes a drive wheel rotatably attached to the vehicle body, and a vehicle control device that controls a drive torque applied to the drive wheel to control the posture of the vehicle body, The vehicle control device estimates the road surface gradient based on the posture of the vehicle body, and fixes the estimated value of the road surface gradient when the absolute value of the vehicle speed is equal to or less than a predetermined threshold value.

  In another vehicle of the present invention, the vehicle speed is a vehicle center-of-gravity moving speed.

  In still another vehicle of the present invention, the center-of-gravity moving speed of the vehicle includes a rotational angular speed of driving wheels.

  In still another vehicle of the present invention, the vehicle control device further calculates the center-of-gravity moving speed of the vehicle based on the rotation state of the drive wheels and the change in the vehicle body posture.

  In yet another vehicle of the present invention, the vehicle has a drive wheel rotatably attached to the vehicle body, and a vehicle control device that controls the attitude of the vehicle body by controlling a drive torque applied to the drive wheel, The vehicle control device estimates the road surface gradient based on the posture of the vehicle body, and fixes the estimated value of the road surface gradient when the absolute value of the center-of-gravity movement acceleration of the vehicle is equal to or less than a predetermined threshold value.

  In still another vehicle of the present invention, the vehicle control device updates the estimated value of the road surface gradient when the absolute value of the vehicle speed is larger than the threshold value.

  According to the configuration of the first aspect, when the vehicle is almost stopped, the vibration of the vehicle body due to the fluctuation of the estimated value of the road surface gradient can be prevented. Therefore, even on a slope, a stable stop state can be maintained regardless of the road surface gradient, and the riding comfort is improved.

  According to the structure of Claim 2 and 5, the state of a vehicle can be grasped | ascertained appropriately and the estimated value of a road surface gradient can be fixed.

  According to the configuration of the fourth aspect, the state where the vehicle is stopped and the vehicle body posture is not changed can be set to the stopped state, and the state of the vehicle can be grasped more appropriately.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing the configuration of a vehicle in a first embodiment of the present invention, and shows a state in which an occupant is moving forward in an accelerated state, and FIG. 2 is a first embodiment of the present invention. 1 is a block diagram showing a configuration of a vehicle control system in FIG.

  In the figure, reference numeral 10 denotes a vehicle according to the present embodiment, which has a body portion 11, a driving wheel 12, a support portion 13, and a riding portion 14 on which an occupant 15 rides, and uses the posture control of an inverted pendulum. Control the attitude of the car body. The vehicle 10 can tilt the vehicle body forward and backward. In the example shown in FIG. 1, the vehicle 10 is accelerating in the direction indicated by the arrow A, and the vehicle body is tilted forward in the traveling direction.

  The drive wheel 12 is rotatably supported by a support portion 13 that is a part of the vehicle body, and is driven by a drive motor 52 as a drive actuator. The shaft of the drive wheel 12 extends in a direction perpendicular to the drawing of FIG. 1, and the drive wheel 12 rotates about the shaft. The drive wheel 12 may be singular or plural, but in the case of plural, the drive wheels 12 are arranged on the same axis in parallel. In the present embodiment, description will be made assuming that there are two drive wheels 12. In this case, each drive wheel 12 is independently driven by an individual drive motor 52. As the drive actuator, for example, a hydraulic motor, an internal combustion engine, or the like can be used, but here, the description will be made assuming that the drive motor 52 that is an electric motor is used.

  The main body 11 that is a part of the vehicle body is supported from below by the support 13 and is positioned above the drive wheels 12. And, in the main body part 11, the riding part 14 functioning as an active weight part can be translated relative to the main body part 11 in the longitudinal direction of the vehicle 10, in other words, the tangential direction of the vehicle body rotation circle It is attached so that it can move relatively.

  Here, the active weight portion has a certain amount of mass and translates with respect to the main body portion 11, that is, actively moves the front and rear to correct the position of the center of gravity of the vehicle 10. The active weight portion does not necessarily have to be the riding portion 14. For example, the active weight portion may be a device in which a heavy peripheral device such as a battery is attached to the main body portion 11 so as to be translatable. (Weight), a device in which a dedicated weight member such as a balancer is attached to the main body 11 so as to be translatable may be used. Moreover, you may use together the boarding part 14, a heavy peripheral device, an exclusive weight member, etc.

  In the present embodiment, for the sake of explanation, an example will be described in which the riding section 14 in a state in which the occupant 15 is boarded functions as an active weight section. However, the occupant 15 is not necessarily on the riding section 14. For example, when the vehicle 10 is operated by remote control, the occupant 15 may not be on the riding section 14, or cargo may be loaded instead of the occupant 15.

  The riding section 14 is the same as a seat used in automobiles such as passenger cars and buses, and includes a seat surface section 14a, a backrest section 14b, and a headrest 14c, and is attached to the main body section 11 through a moving mechanism (not shown). ing.

  The moving mechanism includes a low-resistance linear moving mechanism such as a linear guide device and an active weight part motor 62 as an active weight part actuator. The active weight part motor 62 drives the riding part 14, and the main body part 11. It is designed to move back and forth in the direction of travel. As the active weight actuator, for example, a hydraulic motor, a linear motor, or the like can be used. However, here, the description will be made assuming that the active weight motor 62 that is a rotary electric motor is used.

  The linear guide device includes, for example, a guide rail attached to the main body 11, a carriage attached to the riding part 14 and sliding along the guide rail, a ball, a roller, and the like interposed between the guide rail and the carriage. Rolling elements. In the guide rail, two track grooves are formed linearly along the longitudinal direction on the left and right side surfaces thereof. Moreover, the cross section of the carriage is formed in a U-shape, and two track grooves are formed on the inner sides of the two opposing side surfaces so as to face the track grooves of the guide rail. The rolling elements are incorporated between the raceway grooves, and roll in the raceway grooves with the relative linear motion of the guide rail and the carriage. The carriage is formed with a return passage that connects both ends of the raceway groove, and the rolling elements circulate through the raceway groove and the return passage.

  The linear guide device includes a brake or a clutch that fastens the movement of the linear guide device. When the operation of the riding section 14 is unnecessary, such as when the vehicle 10 is stopped, the relative positional relationship between the main body section 11 and the riding section 14 is maintained by fixing the carriage to the guide rail with a brake. . When the operation is necessary, the brake is released and the distance between the reference position on the main body 11 side and the reference position on the riding section 14 is controlled to be a predetermined value.

  An input device 30 including a joystick 31 as a target travel state acquisition device is disposed beside the boarding unit 14. The occupant 15 operates the joystick 31 to input travel commands such as acceleration, deceleration, turning, in-situ rotation, stop, and braking of the vehicle 10. If the occupant 15 can operate and input a travel command, another device such as a jog dial, a touch panel, or a push button may be used as the target travel state acquisition device instead of the joystick 31. You can also.

  In addition, when the vehicle 10 is steered by remote control, it can replace with the said joystick 31, and can use the receiver which receives the driving | running | working command from a controller with a wire communication or a radio | wireless as a target driving | running | working state acquisition apparatus. Further, when the vehicle 10 automatically travels according to predetermined travel command data, a data reader that reads travel command data stored in a storage medium such as a semiconductor memory or a hard disk is used as a target travel instead of the joystick 31. It can be used as a status acquisition device.

  In addition, the vehicle 10 includes a control ECU (Electronic Control Unit) 20 as a vehicle control device, and the control ECU 20 includes a main control ECU 21, a drive wheel control ECU 22, and an active weight unit control ECU 23. The control ECU 20, main control ECU 21, drive wheel control ECU 22 and active weight control ECU 23 include calculation means such as a CPU and MPU, storage means such as a magnetic disk and a semiconductor memory, input / output interfaces, and the like. The computer system controls the operation. For example, the computer system is disposed in the main body 11, but may be disposed in the support portion 13 or the riding portion 14. The main control ECU 21, the drive wheel control ECU 22, and the active weight control ECU 23 may be configured separately or may be configured integrally.

  The main control ECU 21 functions as a part of the drive wheel control system 50 that controls the operation of the drive wheel 12 together with the drive wheel control ECU 22, the drive wheel sensor 51, and the drive motor 52. The drive wheel sensor 51 includes a resolver, an encoder, and the like, functions as a drive wheel rotation state measuring device, detects a drive wheel rotation angle and / or rotation angular velocity indicating a rotation state of the drive wheel 12, and transmits it to the main control ECU 21. To do. The main control ECU 21 transmits a drive torque command value to the drive wheel control ECU 22, and the drive wheel control ECU 22 supplies an input voltage corresponding to the received drive torque command value to the drive motor 52. The drive motor 52 applies drive torque to the drive wheels 12 in accordance with the input voltage, thereby functioning as a drive actuator.

  The main control ECU 21 functions as a part of the active weight part control system 60 that controls the operation of the riding part 14 that is the active weight part together with the active weight part control ECU 23, the active weight part sensor 61, and the active weight part motor 62. To do. The active weight part sensor 61 is composed of an encoder or the like, functions as an active weight part movement state measuring device, detects the active weight part position and / or movement speed indicating the movement state of the riding part 14, and transmits it to the main control ECU 21. To do. Further, the main control ECU 21 transmits an active weight part thrust command value to the active weight part control ECU 23, and the active weight part control ECU 23 sends an input voltage corresponding to the received active weight part thrust command value to the active weight part motor. 62. The active weight motor 62 applies thrust to the riding section 14 to translate the riding section 14 in accordance with the input voltage, thereby functioning as an active weight actuator.

  Further, the main control ECU 21 functions as a part of the vehicle body control system 40 that controls the posture of the vehicle body together with the drive wheel control ECU 22, the active weight unit control ECU 23, the vehicle body inclination sensor 41, the drive motor 52, and the active weight unit motor 62. . The vehicle body tilt sensor 41 includes an acceleration sensor, a gyro sensor, and the like, and functions as a vehicle body tilt state measuring device. The vehicle body tilt sensor 41 detects a vehicle body tilt angle and / or tilt angular velocity indicating the tilt state of the vehicle body, and transmits the detected vehicle body tilt angle to the main control ECU 21. The main control ECU 21 transmits a drive torque command value to the drive wheel control ECU 22 and transmits an active weight portion thrust command value to the active weight portion control ECU 23.

  The main control ECU 21 receives a travel command from the joystick 31 of the input device 30. The main control ECU 21 transmits a drive torque command value to the drive wheel control ECU 22 and transmits an active weight portion thrust command value to the active weight portion control ECU 23.

  The control ECU 20 functions as a road surface gradient estimating unit that estimates a road surface gradient based on a change in the travel state of the vehicle 10 and the vehicle body posture over time. Further, it functions as a target vehicle body posture determination means for determining a target vehicle body posture, that is, a vehicle body tilt state and / or an active weight portion movement state, according to the target travel state and the road surface gradient. Furthermore, it functions as an actuator output determining means that determines the output of each actuator according to the traveling state and vehicle body posture of the vehicle 10 acquired by each sensor, and the target traveling state, target vehicle body posture, and road gradient. Furthermore, it functions as road surface gradient acquisition means for acquiring the road surface gradient in the front-rear direction of the vehicle 10. Furthermore, it functions as a climbing torque determining means for determining the drive torque to be applied according to the road surface gradient. Furthermore, it functions as a center-of-gravity correction amount determining means for determining the center-of-gravity correction amount of the vehicle body according to the climbing torque.

  Each sensor may acquire a plurality of state quantities. For example, an acceleration sensor and a gyro sensor may be used in combination as the vehicle body tilt sensor 41, and the vehicle body tilt angle and the tilt angular velocity may be determined from both measured values.

  Next, the operation of the vehicle 10 configured as described above will be described. First, an outline of the travel and attitude control process will be described.

  FIG. 3 is a schematic diagram showing the operation of the vehicle on the slope in the first embodiment of the present invention, and FIG. 4 is a flowchart showing the operation of the vehicle running and attitude control processing in the first embodiment of the present invention. It is. FIG. 3A shows an example of operation according to the prior art for comparison, and FIG. 3B shows the operation according to the present embodiment.

  In the present embodiment, the riding section 14 functions as an active weight section, and as shown in FIG. 3 (b), the center of gravity of the vehicle 10 is actively moved by translating, that is, moving back and forth. It is to be corrected. As a result, in order to stop the vehicle 10 on a slope, that is, so that the vehicle 10 does not move in the downward direction, a driving torque is applied to the drive wheels 12 and the reaction torque, which is the reaction, acts on the vehicle body. The car body never tilts downward. Also, when traveling on a slope, the vehicle body does not tilt downward and can travel stably.

  On the other hand, if the center of gravity position correction according to the road surface gradient is not performed as in the conventional vehicle described in the section “Background Art”, the vehicle 10 is on a slope as shown in FIG. Since the reaction of the drive torque applied to the drive wheels 12 to stop the operation, that is, the reaction torque acts on the vehicle body, the vehicle body tilts downward. Even when traveling on a slope, it is not possible to perform stable vehicle body posture and travel control.

  Therefore, in the present embodiment, the vehicle 10 can stably stop and travel regardless of the road gradient by executing the travel and attitude control processing.

  In the running and posture control process, the control ECU 20 first executes a state quantity acquisition process (step S1), and the driving wheel is driven by each sensor, that is, the driving wheel sensor 51, the vehicle body tilt sensor 41, and the active weight sensor 61. 12 rotation states, vehicle body inclination states, and riding portion 14 movement states are acquired.

  Next, the control ECU 20 executes a road surface gradient acquisition process (step S2), and the state quantity acquired in the state quantity acquisition process, that is, the rotation state of the drive wheels 12, the inclination state of the vehicle body, and the movement of the riding section 14 are performed. Based on the state and the output values of the actuators, that is, the output values of the drive motor 52 and the active weight motor 62, the road surface gradient is estimated by the observer. Here, the observer is a method of observing the internal state of the control system based on a dynamic model, and is configured by wired logic or soft logic.

  Next, the control ECU 20 executes a target travel state determination process (step S3), and based on the operation amount of the joystick 31, the target value of the acceleration of the vehicle 10 and the target value of the rotational angular velocity of the drive wheels 12 are obtained. decide.

  Next, the control ECU 20 executes target body posture determination processing (step S4), and the road surface gradient acquired by the road surface gradient acquisition processing and the acceleration target of the vehicle 10 determined by the target travel state determination processing. Based on the value, a target value of the vehicle body posture, that is, a target value of the vehicle body inclination angle and the active weight portion position is determined.

  Finally, the control ECU 20 executes an actuator output determination process (step S5), and determines each state quantity acquired by the state quantity acquisition process, the road surface gradient acquired by the road surface gradient acquisition process, and the target travel state. Based on the target travel state determined by the processing and the target vehicle body posture determined by the target vehicle body posture determination process, the outputs of the actuators, that is, the outputs of the drive motor 52 and the active weight motor 62 are determined.

  Next, details of the traveling and attitude control processing will be described. First, the state quantity acquisition process will be described.

  FIG. 5 is a diagram showing a vehicle dynamic model and its parameters according to the first embodiment of the present invention, and FIG. 6 is a flowchart showing an operation of state quantity acquisition processing according to the first embodiment of the present invention.

In the present embodiment, state quantities and parameters are represented by the following symbols. FIG. 5 shows some of the state quantities and parameters.
θ _W : Drive wheel rotation angle [rad]
θ ₁ : Body tilt angle (vertical axis reference) [rad]
λ _S : Active weight part position (vehicle center point reference) [m]
τ _W : Driving torque (total of two driving wheels) [Nm]
S _S : Active weight part thrust [N]
g: Gravity acceleration [m / s ² ]
η: Road surface slope [rad]
m _W : Drive wheel mass (total of two drive wheels) [kg]
R _W : Driving wheel contact radius [m]
I _W : Moment of inertia of driving wheel (total of two driving wheels) [kgm ² ]
D _W : viscosity damping coefficient [Nms / rad] for driving wheel rotation
m ₁ : Body mass (including active weight) [kg]
l ₁ : Body center-of-gravity distance (from axle) [m]
I ₁ : Body inertia moment (around the center of gravity) [kgm ² ]
D ₁ : Viscous damping coefficient for vehicle body tilt [Nms / rad]
m _S : Active weight part mass [kg]
l _S : Active weight part center of gravity distance (from axle) [m]
I _S : Active weight part inertia moment (around the center of gravity) [kgm ² ]
D _S : Viscous damping coefficient [Nms / rad] for active weight translation

  As described above, in the present embodiment, the road surface gradient is estimated based on the driving torque output from the driving motor 52 and the driving wheel rotation angular acceleration, the vehicle body inclination angular acceleration, and the active weight moving acceleration as the state quantities. . In this case, not only the driving wheel rotation angular acceleration indicating the rotation state of the driving wheel 12, but also the vehicle body inclination angular acceleration and the active weight moving acceleration indicating the vehicle body posture change are taken into consideration. That is, a change in the posture of the vehicle body, which is an element peculiar to the so-called inverted vehicle using the posture control of the inverted pendulum, is taken into consideration.

  Conventionally, since the road surface gradient is estimated based on the driving torque and the driving wheel rotation angular acceleration, a large error may occur in the estimated value of the road surface gradient particularly when the posture of the vehicle body is changing. However, in the present embodiment, the road surface gradient is estimated in consideration of the vehicle body inclination angle acceleration indicating the posture change of the vehicle body and the active weight portion movement acceleration, so that no large error occurs and the road surface is extremely accurate. The gradient can be estimated.

  Generally, in an inverted type vehicle, the center of gravity of the vehicle body moves back and forth relative to the drive wheels, so that the center of gravity of the vehicle may move back and forth even when the drive wheels are stopped. Therefore, in order to estimate the road gradient with high accuracy from the acceleration of the center of gravity and the driving force or the driving torque, it is necessary to consider such influence. In a general inverted type vehicle, since the weight ratio of the vehicle body to the entire vehicle is high, such an influence becomes large particularly when the vehicle is stopped.

  Note that the high-frequency component of the estimated value can be removed by applying a low-pass filter to the road surface gradient value. In this case, a time delay occurs in the estimation, but the vibration caused by the high frequency component can be suppressed.

  In the present embodiment, the gravitational component due to the driving force, inertial force, and road surface gradient is taken into consideration, but the rolling resistance of the driving wheel 12, the viscous resistance due to the friction of the rotating shaft, the air resistance acting on the vehicle 10, etc. May be considered as a side effect.

  In the present embodiment, a linear model related to the rotational motion of the drive wheel 12 is used. However, a more accurate nonlinear model may be used, or a model for vehicle body tilting motion or active weight portion translational motion. May be used. For nonlinear models, functions can also be applied in the form of maps.

  Further, in order to simplify the calculation, it is not necessary to consider the change in the body posture.

  Next, the target travel state determination process will be described.

  FIG. 8 is a flowchart showing the operation of the target travel state determination process in the first embodiment of the present invention.

  In the determination process of the target travel state, the main control ECU 21 first acquires a steering operation amount (step S3-1). In this case, the occupant 15 acquires the operation amount of the joystick 31 that is operated to input a travel command such as acceleration, deceleration, turning, on-site rotation, stop, and braking of the vehicle 10.

  Subsequently, the main control ECU 21 determines a target value for vehicle acceleration based on the acquired operation amount of the joystick 31 (step S3-2). For example, a value proportional to the amount of operation of the joystick 31 in the front-rear direction is set as a target value for vehicle acceleration.

Subsequently, the main control ECU 21 calculates the target value of the drive wheel rotational angular velocity from the determined target value of the vehicle acceleration (step S3-3). For example, by integrating the target value of the vehicle acceleration time, a value obtained by dividing the driving wheel contact radius R _W and the target value of the drive wheel rotation angular velocity.

  Next, the target vehicle body posture determination process will be described.

  FIG. 9 is a graph showing changes in the target value of the active weight portion position and the target value of the vehicle body tilt angle in the first embodiment of the present invention, and FIG. 10 shows the target vehicle body posture in the first embodiment of the present invention. It is a flowchart which shows the operation | movement of a determination process.

  In the target body posture determination process, the main control ECU 21 first determines the target value of the active weight portion position and the target value of the vehicle body tilt angle (step S4-1). In this case, based on the target value of the vehicle acceleration determined by the target travel state determination process and the road surface gradient η acquired by the road surface gradient acquisition process, the active weight is calculated by the following equations (2) and (3). The target value of the part position and the target value of the vehicle body inclination angle are determined.

  Subsequently, the main control ECU 21 calculates the remaining target value (step S4-2). That is, the target values of the drive wheel rotation angle, the vehicle body inclination angular velocity, and the active weight portion moving speed are calculated by time differentiation or time integration of each target value.

  As described above, in the present embodiment, not only the inertial force and drive motor reaction torque acting on the vehicle body in accordance with the vehicle acceleration, but also the reaction torque acting on the vehicle body in accordance with the climbing torque according to the road surface gradient η is considered. Thus, the target value of the vehicle body posture, that is, the target value of the active weight portion position and the target value of the vehicle body tilt angle are determined.

  At this time, the center of gravity of the vehicle body is moved so that the torque that acts on the vehicle body to tilt the vehicle body, that is, the vehicle body tilt torque is canceled out by the action of gravity. For example, when the vehicle 10 accelerates and climbs a hill, the riding section 14 is moved forward, or the vehicle body is further tilted forward. Further, when the vehicle 10 decelerates and goes down a hill, the riding section 14 is moved backward, or the vehicle body is further tilted backward.

  In the present embodiment, as shown in FIG. 9, first, the riding section 14 is moved without tilting the vehicle body, and when the riding section 14 reaches the active weight movement limit, the tilting of the vehicle body is started. . For this reason, the vehicle body does not tilt forward and backward with respect to fine acceleration / deceleration, so that the ride comfort for the occupant 15 is improved. Further, if the slope is not particularly steep, the vehicle body is kept upright even on a slope, so that it is easy to ensure visibility for the occupant 15. Furthermore, if the slope is not particularly steep, the vehicle body will not be greatly inclined even on a slope, so that a part of the vehicle body is prevented from coming into contact with the road surface.

  In the present embodiment, it is assumed that the active weight part movement limit is equal between the front and the rear, but when the front and rear are different, the inclination of the vehicle body is changed according to each limit. The presence or absence may be switched. For example, when the braking performance is set higher than the acceleration performance, it is necessary to set the rear active weight portion movement limit farther than the front.

  In this embodiment, when the acceleration is low or the gradient is gentle, only the movement of the riding section 14 is used, but some or all of the vehicle body tilt torque is handled by the vehicle body tilt. Also good. By tilting the vehicle body, the longitudinal force acting on the occupant 15 can be reduced.

  Further, in the present embodiment, an expression based on a linearized dynamic model is used, but an expression based on a more accurate nonlinear model or a model considering viscous resistance may be used. Note that if the equation is nonlinear, the function can be applied in the form of a map.

  Next, the actuator output determination process will be described.

  FIG. 11 is a flowchart showing the operation of the actuator output determination process in the first embodiment of the present invention.

  In the actuator output determination process, the main control ECU 21 first determines the feedforward output of each actuator (step S5-1). In this case, the feedforward output of the drive motor 52 is determined from each target value and the road surface gradient η by the following equation (4), and the feedforward output of the active weight motor 62 is also obtained by the following equation (5). To decide.

  In this way, by automatically adding a climbing torque according to the road surface gradient η, that is, by correcting the driving torque according to the road surface gradient η, the same steering sensation as on a flat ground can be obtained. Can be provided. That is, even if the occupant 15 releases his / her hand from the joystick 31 after stopping on a slope, the vehicle 10 does not move. Even on a slope, acceleration / deceleration similar to that on a flat ground can be performed for a certain steering operation of the joystick 31.

  Thus, in the present embodiment, more accurate control is realized by theoretically giving a feedforward output.

  Note that the feed-forward output can be omitted as necessary. In this case, the feedback control indirectly gives a value close to the feedforward output with a steady deviation. Further, the steady deviation can be reduced by applying an integral gain.

  Subsequently, the main control ECU 21 determines the feedback output of each actuator (step S5-2). In this case, the feedback output of the drive motor 52 is determined from the deviation between each target value and the actual state quantity by the following equation (6), and the feedback of the active weight motor 62 is also obtained by the following equation (7). Determine the output.

Note that nonlinear feedback control such as sliding mode control can also be introduced. As simpler control, some of the feedback gains excluding K _W2 , K _W3, and K _S5 may be set to zero. Further, an integral gain may be introduced in order to eliminate the steady deviation.

  Finally, the main control ECU 21 gives a command value to each element control system (step S5-3). In this case, the main control ECU 21 transmits the sum of the feedforward output and the feedback output determined as described above to the drive wheel control ECU 22 and the active weight part control ECU 23 as the drive torque command value and the active weight part thrust command value. .

  As described above, in the present embodiment, the road surface gradient η is estimated by the observer, the climbing torque is applied, and the riding section 14 is moved upward. Therefore, the vehicle body can be held upright on a slope and can cope with a steep slope. Further, an apparatus for measuring the road surface gradient η is not required, and the structure can be simplified and the cost can be reduced.

Further, since the road surface gradient η is estimated in consideration of the vehicle body inclination angle θ ₁ indicating the vehicle body posture and the active weight portion position λ _S , the road surface gradient η can be estimated with extremely high accuracy without causing a large error. Can do.

  Next, a second embodiment of the present invention will be described. In addition, about the thing which has the same structure as 1st Embodiment, the description is abbreviate | omitted by providing the same code | symbol. The description of the same operation and the same effect as those of the first embodiment is also omitted.

  FIG. 12 is a flowchart showing the operation of the road surface gradient acquisition process according to the second embodiment of the present invention.

In the first embodiment, even when the vehicle stops or runs on a slope, the drive torque output by the drive motor 52, the drive wheel rotational angular acceleration, the vehicle body tilt angular acceleration, and the active weight unit as state quantities are always obtained. The road surface gradient η is sequentially estimated based on the movement acceleration, and the value is updated. At this time, the estimated value of the road gradient η fluctuates mainly due to the following causes (A) to (C). In the running and attitude control process, the outputs of the drive motor 52 and the active weight motor 62 are determined based on the estimated value of the road surface gradient η. Therefore, if the estimated value of the road surface gradient η fluctuates, The output of the weight part motor 62 may also fluctuate and the vehicle body may vibrate.
(A) Noise included in each state quantity sensed by each sensor (drive wheel rotation angle θ _W , vehicle body inclination angle θ ₁ , active weight portion position λ _S, etc.) C) Effects of dry friction (particularly the difference between static and dynamic friction)
The noise of each state quantity can be solved by applying a low-pass filter. However, if the low-pass filter is applied, the estimation time is delayed, so that the response to changes in the road surface gradient η is delayed in the running state. become.

  In addition, when the vehicle 10 is almost stopped, the estimated value fluctuates due to the difference between the static friction and the dynamic friction of the dry friction, and if this is influenced by the time delay of the acceleration calculation, intermittent vibration (stick-slip phenomenon) occurs. appear.

  Although the influence of (a) is not limited to the stop state, the influence of the synergistic effect with the (a) and (c) is great, and the human sensitivity is the vibration in the stop state rather than the vibration in the running state. Therefore, in the present embodiment, control is performed based on the fixed value without changing the estimated value of the road surface gradient η for the stop state of the vehicle 10 as a target.

  Note that the fluctuation of the estimated value of the road surface gradient η is the same when the vehicle 10 is not moving completely but also when it is moving slightly, so the absolute value of the speed of the vehicle 10 is a predetermined threshold value. When it is below, the estimated value of the road surface gradient η is fixed and not changed. More precisely, when the absolute value of the center of gravity moving speed or the center of gravity moving acceleration of the vehicle 10 is not more than a predetermined threshold, the estimated value of the road surface gradient η is not changed.

  When the absolute value of the speed of the vehicle 10 is equal to or less than the predetermined threshold, the vehicle 10 is substantially stopped. If the vehicle 10 is stopped, the road surface gradient η is unchanged. It is reasonable to fix the estimated value to be unchanged.

  Thereby, even if it is a slope, the stable stop state can be maintained irrespective of the road surface gradient η, and the riding comfort of the vehicle 10 becomes good.

  Note that the configuration of the vehicle 10 in the present embodiment is the same as that in the first embodiment, and thus the description thereof is omitted.

Next, details of the traveling and posture control processing in the present embodiment will be described. Note that the state quantity acquisition process, the target travel state determination process, the target vehicle body posture determination process, and the actuator output determination process are the same as those in the first embodiment, and a description thereof will be omitted. Only the acquisition process will be described.

Subsequently, the main control ECU 21 determines whether or not the vehicle 10 is moving based on the calculated vehicle center-of-gravity speed V _G (step S2-12). Specifically, it is determined that the vehicle 10 is moving when the absolute value of the vehicle center-of-gravity speed V _G is greater than a predetermined threshold, and the vehicle 10 is determined when the absolute value of the vehicle center-of-gravity speed V _G is equal to or less than the threshold. It is determined that it is not moving, that is, it is stopped.

Note that high-frequency components in the calculated value of the vehicle center-of-gravity velocity V _G can be removed by applying a low-pass filter. Since the value of the vehicle center-of-gravity speed V _G is used only for determining whether or not the vehicle 10 is moving, even if a low-pass filter is applied, there is no time delay effect on the control system.

Further, in order to simplify the calculation of the vehicle center-of-gravity speed V _G , it is not necessary to consider the change in the vehicle body posture.

Furthermore, although the example which employ | adopted the same threshold value is demonstrated here irrespective of the transition direction of the state in which the vehicle 10 is moving, and the state in which the vehicle 10 has stopped, the threshold value which changes with the said transition directions is employ | adopted. You can also That is, when it is determined that the vehicle 10 is moving in the control step of the previous travel and posture control process, the threshold for determining that the vehicle 10 is stopped this time and the control of the previous travel and posture control process When it is determined that the vehicle 10 is stopped in the step, the threshold value for determining that the vehicle 10 is moving this time can be set to a different value. Thus, by adopting a threshold value that differs depending on the transition direction, chattering that tends to occur when the value of the vehicle center-of-gravity velocity V _G is near the threshold value can be prevented.

The main control ECU 21 estimates the road surface gradient η only when the vehicle 10 is moving (step S2-13). In this case, the road surface gradient η is estimated in the same manner as the road surface gradient acquisition process in the first embodiment, and the estimated value is updated. That is, the main control ECU 21 determines whether the vehicle 10 is moving or stopped, and estimates the road surface gradient η when the vehicle 10 is moving (the absolute value of the vehicle center-of-gravity velocity V _G is greater than a predetermined threshold value). Then, the estimated value of the road surface gradient η is updated with the estimated value. Further, when the vehicle 10 is stopped (the absolute value of the vehicle center-of-gravity velocity V _G is equal to or less than a predetermined threshold value), the estimated value of the road surface gradient η in the control step of the previous traveling and posture control process is used as it is.

Thus, in the present embodiment, when the gravity center moving speed of the vehicle 10, that is, the absolute value of the vehicle gravity center speed V _G is equal to or less than a predetermined threshold value, the estimated value of the road surface gradient η is fixed and not changed. Thereby, when the vehicle center-of-gravity velocity V _G is very low and the vehicle is almost stopped, it is possible to prevent the vibration of the vehicle body caused by the fluctuation of the estimated value of the road surface gradient η. Therefore, even on a slope, a stable stop state can be maintained regardless of the road surface gradient η, and the riding comfort is improved.

  In the present embodiment, the stop state of the vehicle 10 is determined based on the center-of-gravity moving speed of the vehicle 10, but may be determined based on the center-of-gravity moving acceleration of the vehicle 10.

Further, the determination may be made based on the drive wheel rotation angle θ _W (the amount of movement within a predetermined time).

  Further, in this embodiment, when it is determined again that the vehicle 10 is moving, the estimated value change of the road surface gradient η may be discontinuous, but this is smoothly transitioned by a low-pass filter. Also good. Thereby, the shock of the vehicle motion and the vehicle body posture accompanying the discontinuity of the estimated value of the road surface gradient η can be reduced.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

It is the schematic which shows the structure of the vehicle in the 1st Embodiment of this invention, and is a figure which shows the state which is carrying out acceleration advance in the state which the passenger | crew got on. It is a block diagram which shows the structure of the control system of the vehicle in the 1st Embodiment of this invention. It is the schematic which shows the operation | movement of the vehicle on the slope in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the driving | running | working and attitude | position control processing of the vehicle in the 1st Embodiment of this invention. It is a figure which shows the dynamic model of the vehicle in the 1st Embodiment of this invention, and its parameter. It is a flowchart which shows the operation | movement of the acquisition process of the state quantity in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the acquisition process of the road surface gradient in the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the target driving state in the 1st Embodiment of this invention. It is a graph which shows the change of the target value of the active weight part position in the 1st Embodiment of this invention, and the target value of a vehicle body tilt angle. It is a flowchart which shows the operation | movement of the determination process of the target vehicle body attitude | position in the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement of the determination process of the actuator output in the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the acquisition process of the road surface gradient in the 2nd Embodiment of this invention.

Explanation of symbols

10 Vehicle 12 Drive wheel 20 Control ECU

Claims (5)

A drive wheel rotatably mounted on the vehicle body,
A vehicle control device for controlling the attitude of the vehicle body by controlling the drive torque applied to the drive wheels,
The vehicle control device estimates a road surface gradient based on a posture of the vehicle body, and fixes the estimated value of the road surface gradient when an absolute value of a vehicle speed is a predetermined threshold value or less.   The vehicle according to claim 1, wherein the vehicle speed is a center of gravity moving speed or a center of gravity moving acceleration of the vehicle.   The vehicle according to claim 2, wherein the vehicle control device calculates a center-of-gravity moving speed of the vehicle based on a rotation state of driving wheels and an inclination angle of a vehicle body posture.   The vehicle according to claim 2, wherein the vehicle control device calculates a center-of-gravity movement acceleration of the vehicle based on values obtained by differentiating the rotation angle of the drive wheel and the inclination angle of the vehicle body posture.   The vehicle according to claim 1, wherein the vehicle control device updates the estimated value of the road surface gradient when an absolute value of a vehicle speed is larger than the threshold value.

Images