JP2008290595A - Wheel-body distance control device - Google Patents

Abstract

In a technique using a device for controlling the distance from a wheel to a vehicle body, the horizontality of the vehicle body can be maintained even on uneven roads and laterally inclined roads.
A wheel-vehicle distance control device detects a lateral inclination of a vehicle body with respect to a horizontal plane, and the inclination detecting means detects a right wheel 1RR and a left wheel 1RR of the vehicle in order to reduce the detected inclination. The actuator is controlled so that the distance from the wheel 1RR attached to the lower side due to the tilted to the vehicle body becomes longer than the reference length.
[Selection] Figure 7

Description

  The present invention relates to a wheel-vehicle distance control device that controls a distance from a wheel to a vehicle body.

  Conventionally, devices for controlling the distance from a wheel to a vehicle body such as a vehicle stabilizer system and an active suspension have been used. Such a device controls the distance (hereinafter referred to as a stroke) from each of the left and right wheels to the vehicle body in order to maintain the posture of the vehicle body against the roll motion of the vehicle body due to centrifugal force. . As a result of such control, the stroke of each wheel is returned to the reference length. The reference length is a stroke when the vehicle is stationary on a horizontal plane.

  The technology as described above is a technology based on the premise that the vehicle is traveling on a horizontal and flat road. However, the road surface on which the vehicle travels may be uneven, or may be inclined in the left-right direction of the vehicle (hereinafter referred to as the lateral direction) with respect to the horizontal plane. Even on such uneven roads and laterally inclined roads, if the vehicle body can be kept horizontal, the ride comfort is improved and the load applied to each wheel is made uniform.

  The present invention has been made in view of the above points, and an object of the present invention is to make it possible to maintain the level of a vehicle body even on uneven roads and laterally inclined roads in a technology that uses a device for controlling the distance from a wheel to a vehicle body.

  In order to achieve the above object, the invention according to claim 1 is directed to a distance from the first wheel (1FR) and the third wheel (1RR) attached to the right side in the traveling direction of the vehicle body to the vehicle body, and , Actuators (4F, 4R, 7FL, 7FR, 7RL, 7RR) for changing the distance from the second wheel (1FL) and the fourth wheel (1RL) mounted on the left side toward the traveling direction of the vehicle body to the vehicle body A wheel-vehicle distance control device mounted on a vehicle equipped with a vehicle detects a lateral inclination of the vehicle body with respect to a horizontal plane and reduces the detected inclination. It is to perform actuator control, that is, to perform grounding control, such that the distance from the wheel mounted on the lower side by the detected inclination to the vehicle body becomes longer than the reference length.

  In this way, for example, when the vehicle is traveling on a side slope inclined to the right side, the wheel-to-vehicle distance control device detects the inclination of the vehicle body to the right, and Grounding control is performed so that the stroke is longer than the reference value. By doing so, the lateral inclination of the vehicle body is greatly reduced. In other words, it is the vehicle body tilt reduction control, and the possibility that the vehicle body is kept horizontal is higher than in the past.

  Also, for example, when the vehicle is running on a bumpy road and the right wheel approaches the dent, the right wheel falls slightly into the dent, but the depressed wheel is not completely in contact with the bottom of the dent. There is a case. In such a state, no load is applied to the depressed wheel. However, at this time, the wheel-to-vehicle distance control device detects the inclination of the vehicle body to the right, and performs the grounding control so that the stroke of the right wheel becomes longer than the reference value. By doing in this way, the wheel which fell down contacts the bottom of a hollow, and also possibility that the horizontal inclination of a vehicle body will reduce increases. Therefore, the possibility that the ground contact load to each wheel is equalized becomes higher than before, and the possibility that the vehicle body is kept horizontal becomes higher than before.

  In addition, the wheel-vehicle distance control device according to claim 2 is attached to the left side wheel and the right side wheel on the upper side by the inclination detected by the inclination detecting means in order to reduce the detected inclination. The grounding control of the actuator is performed so that the distance from the wheel to the vehicle body is shorter than the distance between the wheel and the vehicle body when the vehicle is stationary on a horizontal plane.

  In this way, in the above-described example of the lateral slope, the wheel-vehicle distance control device detects the rightward inclination of the vehicle body and shortens the stroke of the left wheel shorter than the reference value. Such ground control is performed. By doing so, the lateral inclination of the vehicle body is greatly reduced. Therefore, the possibility that the vehicle body is kept horizontal is higher than in the past.

  Further, for example, in the above-described example of the uneven road, the wheel-vehicle distance control device detects the inclination of the vehicle body to the right and performs the grounding control so that the stroke of the left wheel is shorter than the reference value. By doing so, the lateral inclination of the vehicle body is greatly reduced. Therefore, the possibility that the vehicle body is kept horizontal is higher than in the past.

  In addition, on a bumpy road, when only one wheel is approaching the depression, the vehicle body may be supported by the other wheel, so that the vehicle may not lean in either direction. For such a case, as described in claim 3, the wheel-body distance control device may detect the ground load of the four wheels. At this time, the wheel-vehicle distance control device may further control the actuator so as to increase the distance from the wheel having the smaller ground load detected among the four wheels to the vehicle body.

  Such an operation takes advantage of the fact that when one of the wheels approaches the depression on the uneven road and leaves the road surface, the ground contact load of the wheel decreases. Even when one of the wheels approaches the depression on the bumpy road by the above operation, the wheel with the lower ground contact load detected, that is, the wheel on the depression is removed from the vehicle. By separating the wheels, the wheels that are separated from the road surface on the uneven road can be brought into contact with the road surface again. In other words, this control is a contact load difference reduction control.

  According to a fourth aspect of the present invention, the wheel-vehicle distance control device is configured to load the first wheel and the load of the fourth wheel at a diagonal position with respect to the first wheel based on the detection result of the ground load. And the sum of the loads of the second wheel and the third wheel in a diagonal position with respect to the second wheel, and for at least one wheel of the set of wheels having a smaller sum, The control means may be controlled to increase the distance from the wheel to the vehicle body.

  In this way, even when the vehicle body is supported by three wheels and the remaining one wheel is on the depression and the vehicle body does not tilt even if it is away from the road surface, the wheels on the depression are The distance between the wheel and the vehicle body is increased so as to be grounded.

  In addition, the wheel-vehicle distance control apparatus determines whether the lateral acceleration applied to the vehicle body is due to centrifugal force or the road surface inclination, and determines that it is due to the road surface inclination. On the basis of this, the grounding control may be permitted, and the grounding control may be prohibited based on the determination that the grounding control is based on the centrifugal force. By performing such control, unnecessary grounding control can be suppressed.

In addition, the code | symbol in the parenthesis in the said claim shows the correspondence of the term described in the claim, and the specific thing described in embodiment mentioned later in order to illustrate the said term It is.

(First embodiment)
The first embodiment of the present invention will be described below. FIG. 1 shows an example of mounting various devices on a vehicle 100 to which the present embodiment is applied. In the vehicle 100, in the vicinity of the wheels 1FR, 1FL, 1RR, 1RL, stroke sensors 5FR, 5FL, 5RR for detecting distances (hereinafter referred to as strokes) from the corresponding wheels to the vehicle body in the vertical direction of the vehicle, respectively. 5RL is installed. In addition, wheel speed sensors 6FR, 6FL, 6RR, 6RL for detecting the respective wheel speeds are mounted in the vicinity of the wheels 1FR, 1FL, 1RR, 1RL. Further, load sensors 8FR, 8FL, 8RR, and 8RL for detecting the ground load of the corresponding wheels are attached in the vicinity of the wheels 1FR, 1FL, 1RR, and 1RL, respectively.

  In addition, suspension actuators 7FR, 7FL, 7RR, 7RL for controlling the corresponding suspensions are mounted in the vicinity of the wheels 1FR, 1FL, 1RR, 1RL. The suspension actuators 7FR, 7FL, 7RR, 7RL can control the strokes of the wheels 1FR, 1FL, 1RR, 1RL.

  In addition, to the stabilizer bar for the right rear wheel 1RR and the left rear wheel 1RL, which are drive wheels, a force in the vertical direction of the vehicle is applied to the right rear wheel 1RR and the left rear wheel 1RL in order to stabilize the posture of the vehicle body. A stabilizer actuator 4R is provided. The stabilizer bar for the right front wheel 1FR and the left front wheel 1FL, which are driven wheels, includes a stabilizer actuator 4F that applies a vehicle vertical force to the right front wheel 1FR and the left front wheel 1FL in order to stabilize the posture of the vehicle body. Is provided.

  These stabilizer actuators 4F and 4R have a mechanism (for example, a well-known motor mechanism) that applies a torsion force to each of the stabilizer bars, and can control the torsion force. As the torsional force applied by the rear wheel stabilizer actuator 4R changes, the force applied to each of the drive wheels 1RR and 1RL changes. Further, the force applied to each of the driven wheels 1FR and 1FL changes as the torsional force applied by the front wheel stabilizer actuator 4F changes. By such an operation, the stabilizer actuators 4F, 4R can control the strokes of the wheels 1FR, 1FL, 1RR, 1RL.

  In addition, a steering angle sensor 9, an acceleration sensor 11, a manual switch 13, and a suspension ECU 15 are mounted in the vehicle 100. Stabilizer actuators 4F, 4R, stroke sensors 5FR, 5FL, 5RR, 5RL, wheel speed sensors 6FR, 6FL, 6RR, 6RL, suspension actuators 7FR, 7FL, 7RR, 7RL, load sensors 8FR, 8FL, 8RR, 8RL, steering angle sensor 9, the acceleration sensor 11, the manual switch 13, and the suspension ECU 15 are connected to the in-vehicle LAN 50, and can exchange signals with each other via the in-vehicle LAN 50.

  The steering angle sensor 9 is a device that detects a steering angle as a result of applying a predetermined gear ratio to an operation angle of a steering wheel by a driver and outputs the detection result. The acceleration sensor 11 is a device that detects acceleration in the longitudinal direction of the vehicle, acceleration in the vertical direction of the vehicle, acceleration in the lateral direction of the vehicle, and outputs a signal corresponding to the detected acceleration. The manual switch 13 is a device that accepts a user operation and outputs a signal corresponding to the content of the accepted operation.

  The suspension ECU 15 is a device that performs posture control and ground contact control. In the posture control, the suspension ECU 15 estimates the roll amount due to the centrifugal force of the vehicle body based on a signal from the acceleration sensor 11 and the like, and based on the estimated roll amount, the suspension actuator 7FR, 7FL, 7RR, 7RL or stabilizer actuators 4F, 4R are controlled.

  This attitude control is aimed at reducing the roll of the car body on the premise of a flat and horizontal road surface, so the wheel stroke whose stroke is shorter than the reference length can be extended beyond the reference length. The stroke of the wheel whose stroke is longer than the reference length is not shortened beyond the reference length. Here, extending from the reference length or reducing from the reference length refers to a change from the stroke value when the vehicle is stationary on a horizontal plane.

  In the ground contact control, the suspension ECU 15 keeps the vehicle body horizontal when the vehicle 100 is traveling on a laterally inclined road or a bumpy road, and improves the ground contact of the wheels 1FR, 1FL, 1RR, 1RL. 4F, 4R, or suspension actuators 7FR, 7FL, 7RR, 7RL are controlled.

  This grounding control is a control for keeping the vehicle body level against the slope of the road surface on lateral slopes and bumpy roads. Therefore, the wheel stroke, whose stroke is shorter than the reference length, exceeds the reference length. Or extend the stroke of the wheel whose stroke is longer than the reference length beyond the reference length. Details of this grounding control will be described later.

  FIG. 2 shows the functions of the suspension ECU 15 in detail. The suspension ECU 15 may be realized as a normal microcomputer. In that case, the suspension ECU 15 implements the functions described below by causing the CPU to execute a predetermined program. Alternatively, the suspension ECU 15 may have a dedicated circuit configuration that implements functions as described below.

  The suspension ECU 15 includes a vehicle body lateral direction tilt amount detection unit 15a, a vehicle body speed detection unit 15b, a grounding control calculation unit 15c, an attitude control calculation unit 15d, an unevenness / lateral inclination determination unit 15e, a selection unit 15f, and a drive unit 15g. ing.

  The vehicle body lateral direction tilt amount detection unit 15a detects the lateral direction tilt amount of the vehicle body and outputs the detection result to the vehicle body speed detection unit 15b. Specifically, the lateral inclination angle θ of the vehicle body is calculated according to the equation of sin θ = Gy / g based on the detection value Gy of the lateral acceleration applied to the vehicle body 100 among the outputs from the acceleration sensor 11. To do. Here, the value g is the gravitational acceleration, the positive direction of the detection value Gy is the right direction of the vehicle 100, and the inclination angle θ is the angle at which the vehicle body is inclined downward from the horizontal state. This equation is established on the assumption that the vehicle is not traveling so as to receive centrifugal force. However, on uneven roads and laterally inclined roads, the speed of the vehicle is often low and the vehicle is traveling straight, so this equation holds approximately with practical accuracy.

  The vehicle body speed detection unit 15b detects the moving speed of the vehicle 100, that is, the vehicle body speed, and outputs the detected vehicle body speed to the selection unit 15f. The vehicle body speed may be determined by a known method from the four wheel speeds obtained from the wheel speed sensors 6FR, 6FL, 6RR, and 6RL, or may be determined by using the longitudinal acceleration of the vehicle received from the acceleration sensor 11. You may come to do.

  The grounding control calculation unit 15c performs the above-described calculation for grounding control based on the detection result of the lateral lean amount of the vehicle body received from the vehicle lateral direction tilt amount detection unit 15a. Specifically, in order to reduce the inclination of the vehicle body until the calculation result of the inclination angle of the vehicle body is repeatedly obtained from the vehicle body lateral inclination amount detection unit 15a and the obtained result matches zero within a predetermined allowable error range. In addition, control signals to the stabilizer actuators 4F, 4R or the suspension actuators 7FR, 7FL, 7RR, 7RL are output to the selection unit 15f. That is, the ground control calculation unit 15c outputs a feedback control signal for making the lateral lean amount of the vehicle body zero to the selection unit 15f.

  The control signal to the stabilizer actuators 4F and 4R increases the stroke of one or both of the wheels (hereinafter referred to as the lower wheels) attached to the vehicle body position on the lower side due to the calculated vehicle body inclination. In addition, among the wheels attached to the vehicle body position on the upper side due to the calculated vehicle body inclination (hereinafter referred to as the upper wheel), a command is issued to reduce the stroke of the wheel having the same front-rear position as the wheel whose stroke increases. Signal.

  Control signals to suspension actuators 7FR, 7FL, 7RR, 7RL reduce the stroke of either one or both of the upper wheels and the command to increase the stroke of one or both of the lower wheels One or both of the signals instructing to be performed.

  The attitude control calculation unit 15d calculates control amounts of the stabilizer actuators 4F and 4R or the suspension actuators 7FR, 7FL, 7RR, and 7RL for the attitude control described above.

  The unevenness / lateral inclination determination unit 15e determines whether the vehicle 100 is traveling on either an uneven road or a lateral inclination road, or neither of them is traveling, and the determination result is selected as a selection unit 15f. Output to. FIG. 3 shows a flowchart of processing that the unevenness / lateral inclination determination unit 15e repeatedly executes for this determination. As shown in this flowchart, the unevenness / lateral inclination determination unit 15e first calculates the calculated lateral acceleration Gye (step 310), then calculates the actual lateral acceleration Gya (step 320), and further calculates the absolute value of these differences. Is determined to be greater than or equal to the reference value Kgy.

Here, the actual lateral acceleration is acceleration in the left-right direction of the vehicle detected by the acceleration sensor 11. The calculated lateral acceleration Gye is an estimated value of acceleration generated by the centrifugal force applied to the vehicle due to the steering of the vehicle 100 or the like. For example, the calculated lateral acceleration Gye is expressed by the equation Gye = δf · Vx ² / {L · (1 + KhVx ² )}.
Calculated by Here, L is the wheel base, Kh is the stability factor, Vx is the vehicle body speed, and δf is the steering angle of the steered wheels 1FL and 1FR detected by the steering angle sensor 9.

  Thus, the actual lateral acceleration is an amount affected by the centrifugal force caused by the turning of the vehicle and the gravity caused by the inclination of the vehicle body. However, the calculated lateral acceleration has a strong correlation with the turning of the vehicle caused by the driver's steering, while the correlation with the tilt of the vehicle body is weak.

  Therefore, the determination in step 330 is a determination as to whether the lateral acceleration applied to the vehicle body is caused by the inclination of the road surface or the centrifugal force applied to the vehicle. Therefore, the process of steps 340 to 360 is repeated while the vehicle 100 is inclined on the uneven road and the vehicle is traveling on the horizontal slope, and the processes of steps 370 to 390 are repeated during other times. . FIG. 4 shows an example 420 of the time change of the absolute value of the calculated lateral acceleration Gye−actual lateral acceleration Gya when the vehicle 100 is traveling on a bumpy road. As shown in this figure, on the uneven road, the determination in step 330 alternates between affirmative and negative in a short time.

  In steps 340 to 360, a period in which the determination result in step 330 is positive in the past predetermined period T0 is counted (step 340), and if the amount of the counted positive time ty is larger than the first reference value τ1. (Step 350), the unevenness / lateral inclination flag is set to 1 (Step 360). That is, if the period during which the road surface is inclined in the lateral direction is equal to or greater than the reference ratio within the predetermined period T0, it is determined that the vehicle has entered a bumpy road or a laterally inclined road.

  In steps 370 to 390, the period in which the determination result in step 330 is negative within the past predetermined period T0 is counted (step 370), and if the amount of the counted negative time tn is greater than the second reference value τ2. (Step 380), the unevenness / lateral inclination flag is set to zero (Step 390). That is, if the period during which the road surface is not inclined in the lateral direction is equal to or greater than the reference ratio within the predetermined period T0, it is determined that the vehicle has separated from the uneven road or the horizontal slope.

  The selection unit 15f determines which of the calculation results of the grounding control calculation unit 15c and the vehicle body speed detection unit 15b is reflected in the actual stabilizer actuators 4F and 4R or the suspension actuators 7FR, 7FL, 7RR, and 7RL. The drive unit 15g is controlled based on the determination result.

  For this determination, the selection unit 15f repeatedly executes the process shown in FIG. In this process, the selection unit 15f allows the ground control to be performed by the last operation on the manual switch 13 (step 110), and the determination result of the unevenness / lateral inclination determination unit 15e indicates that the vehicle 100 is uneven. On the basis of the fact that the vehicle body speed calculated by the vehicle body speed detection unit 15b is equal to or less than a reference speed (for example, 10 km / h) (step 130). A decision to perform control is made (step 150). That is, the control signal from the ground control calculation unit 15c is output to the drive unit 15g. If even one of the above conditions is negative, the ground control is prohibited and a decision to perform posture control is made (step 140). That is, the control signal from the attitude control calculation unit 15d is output to the drive unit 15g.

  The drive unit 15g controls the stabilizer actuators 4F and 4R or the suspension actuators 7FR, 7FL, 7RR, and 7RL in order to perform the ground control or the attitude control in accordance with the control signal from the selection unit 15f.

  Here, as shown in FIG. 6, a case is considered in which the vehicle 100 continuously travels on a laterally inclined road 80 that descends to the right at a reference speed or lower. At this time, it is assumed that the occupant permits the ground control by operating the manual switch 13. In this case, the ground contact control is performed by the control of the suspension ECU 15 as described above. If the ground contact control is not performed, the load is applied to the right wheel rather than the left wheel, so the stroke of the right wheel is shorter than the reference length, and the stroke of the left wheel is longer than the reference length.

  However, when the grounding control is performed, the stroke of either or both of the right wheels is increased until the inclination of the vehicle body becomes substantially zero by the feedback control of the grounding control calculation unit 15c as described above. And (B) one or both of the stroke reductions of either or both of the left wheels. As a result, as shown in FIG. 7, the stroke controlled to shrink out of the stroke of the left wheel was shortened from the reference length to less than the reference length, and the stroke of the right wheel was controlled to extend. The stroke is extended from less than the reference length to more than the reference length.

  By operating the suspension ECU 15 as described above, the vehicle body can be maintained substantially horizontal, so that the ride comfort is improved. In addition, since the load of at least three of the wheels 1FR, 1FL, 1RR, and 1RL is made uniform, the running performance of the vehicle is improved and the steering performance is improved.

  Further, as shown in FIG. 8, a case is considered in which the vehicle 100 continuously travels on a rough road at a speed lower than the reference speed. At this time, it is assumed that the occupant permits the ground control by operating the manual switch 13. In this figure, a solid line 61 indicates the undulation of the line on the road surface through which the left front wheel 1FL and the left rear wheel 1RL of the vehicle 100 pass. A broken line 62 indicates the undulation of the line on the road surface through which the right front wheel 1FR and the right rear wheel 1RR of the vehicle 100 pass.

  In this figure, the left rear wheel 1RL is on a recessed portion 63 that is greatly recessed as compared with other road surfaces. For this reason, the left rear wheel 1RL is separated from the road surface. As a result, the left rear wheel 1RL does not receive any force from the road surface, and the left rear wheel 1RL hangs downward as compared with the right rear wheel 1RR. Then, the vehicle body of the vehicle 100 is inclined toward the hollow portion 63. Thus, there are many cases where the left rear wheel 1RL does not contact the road surface even when the left rear wheel 1RL hangs down and the vehicle body tilts in the direction of the left rear wheel 1RL.

  Also in this case, the ground contact control is performed by the control of the suspension ECU 15 as described above. Then, until the inclination of the vehicle body becomes substantially zero by the feedback control of the ground control calculation unit 15c as described above, (C) an increase in the stroke of one or both of the left wheels, and (D) the right side One or both of the wheel strokes continue to decrease, either or both. As a result, of the right wheel stroke, the stroke controlled to shrink is shortened from the reference length to less than the reference length, and among the left wheel stroke, the stroke controlled to stretch is from less than the reference length. Stretched beyond the reference length.

  By operating the suspension ECU 15 as described above, the vehicle body can be maintained substantially horizontal, so that the ride comfort is improved. In addition, since the load of at least three of the wheels 1FR, 1FL, 1RR, and 1RL is made uniform, the running performance of the vehicle is improved and the steering performance is improved.

  Further, the suspension ECU 15 determines whether the cause of the lateral acceleration applied to the vehicle body is due to the centrifugal force or the inclination of the road surface, and based on the determination that it is due to the inclination of the road surface, Is permitted, and grounding control is prohibited based on the determination that it is due to centrifugal force. By performing such control, unnecessary grounding control is suppressed when the vehicle body is tilted as a result of the centrifugal force.

  In addition, when the vehicle 100 is traveling on a bumpy road, the suspension ECU 15 performs control so that the distance between the wheel and the vehicle body on the hollow portion of the drive wheels 1RR and 1RL is increased. This amplifies the difference between the distance between the wheel on the recess and the vehicle body and the distance between the other wheel and the vehicle body.

  As described above, the suspension ECU 15 amplifies the difference in distance from each of the two wheels to the vehicle body when traveling on the uneven road. In the bumpy road, the wheel on the recessed portion receives no force from the ground, so the distance from the wheel to the vehicle body is longer than the distance from the other wheel to the vehicle body. Therefore, the direction from the other wheel to the wheel on the recess is more inclined to the vehicle body. As a result, there is a high possibility that the wheel on the depression will come into contact with the road surface. And since the wheels are grounded, the running performance and steering performance of the vehicle 100 are improved.

  Further, the suspension ECU 15 prohibits execution of the ground contact control based on the fact that the vehicle body speed is higher than the reference speed. This is because, when the vehicle 100 is traveling at a high speed, there is a high possibility that the vehicle 100 is not traveling on the uneven road, and thus it is not necessary to perform the ground contact control in such a case.

  In addition, when the vehicle body speed is equal to or higher than the reference speed, the execution of the ground contact control is prohibited, and the vehicle body speed information is used to more reliably determine whether the vehicle is traveling on a bumpy road or a laterally inclined road. be able to.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. As shown in FIG. 9, the suspension ECU 15 of the present embodiment differs from the first embodiment in that it further includes a ground load detection unit 15h and performs ground control from the detection result, that is, the ground control calculation unit 15c In addition to the processing of the first embodiment, the left and right ground contact control shown as a flowchart in FIG. 10 is performed on one or both of the pair of the front wheels 1FL and 1FR and the pair of the rear wheels 1RL and 1RR. Is to do.

  Since the car body is stable when supported at three points, if the car body is supported by three of the four wheels 1FR, 1FL, 1RR, and 1RL wheels arranged at the apexes of the quadrangle connecting the four corners of the car body, the rest Even if the wheels are away from the road surface, the vehicle may not tilt. In such a case, the ground control of the first embodiment is not executed. The ground load detection unit 15h and the left / right ground control operate in a complementary manner for such a case.

  The ground load detection unit 15h is a device that calculates the ground load applied to each wheel based on output signals from the load sensors 8FR, 8FL, 8RR, and 8RL. The ground load detection unit 15h estimates the ground load applied to each wheel based on signals from the stroke sensors 5FR, 5FL, 5RR, and 5RL instead of signals from the load sensors 8FR, 8FL, 8RR, and 8RL. It may be like this.

  In the left and right ground control for the target pair, the ground control calculation unit 15c first determines that the absolute value of the difference between the ground load applied to the left wheel and the ground load applied to the right wheel is equal to or greater than the reference load difference K1 ( Step 410), the control signal to the stabilizer actuators 4F, 4R or the suspension actuators 7FR, 7FL, 7RR, 7RL is selected so that the lower one of the left wheels and the right wheels (Step 420) contacts the road surface. Output to the unit 15f or directly to the drive unit 15g. That is, the stabilizer actuators 4F and 4R or the suspension actuators 7FR, 7FL, 7RR, and 7RL are controlled so that the stroke of the wheel is expanded and grounded. By repeating this, the difference between the load applied to the left wheel and the load applied to the right wheel is reduced.

  In this way, even when one of the wheels approaches the depression on the uneven road, the wheel with the lower detected ground load, that is, the wheel on the depression is separated from the vehicle even if the vehicle does not tilt. Thus, the wheel that is away from the road surface on the uneven road can be brought into contact with the road surface again.

(Third embodiment)
Next, a third embodiment of the present invention will be described. The suspension ECU 15 of the present embodiment differs from the second embodiment in that the grounding control calculation unit 15c executes diagonal grounding control shown as a flowchart in FIG. 11 instead of the left and right grounding control. This diagonal contact control is also a control for the case where the vehicle body does not tilt even if one of the wheels approaches the depression on the uneven road.

  In the diagonal ground control, the ground control calculation unit 15c first calculates the sum of the ground load applied to the left front wheel and the ground load applied to the diagonal right rear wheel (hereinafter referred to as the first diagonal load sum). Then, the sum of the ground load applied to the right front wheel and the ground load applied to the diagonal left rear wheel (hereinafter referred to as the second diagonal load sum) is calculated. If it is determined that the absolute value of the difference between the first diagonal load sum and the second diagonal load sum is greater than or equal to the reference load difference K2 (step 510), the first diagonal load sum and the second diagonal load sum Control signals to the stabilizer actuators 4F, 4R or the suspension actuators 7FR, 7FL, 7RR, 7RL are sent to the selection unit 15f or the direct drive unit 15g so that one or both of the wheels corresponding to the lower one are grounded to the road surface. Output to. That is, the stabilizer actuators 4F and 4R or the suspension actuators 7FR, 7FL, 7RR, and 7RL are controlled so that the stroke of the wheel increases.

  In this way, even when one of the wheels approaches the depression on the uneven road, the wheel with the lower detected ground load, that is, the wheel on the depression is separated from the vehicle even if the vehicle does not tilt. Thus, the wheel that is away from the road surface on the uneven road can be brought into contact with the road surface again.

In each of the above embodiments, the suspension ECU 15 corresponds to an example of a wheel-vehicle distance control device. The wheel-vehicle distance control device may include stabilizer actuators 4F, 4R and suspension actuators 7FR, 7FL, 7RR, 7RL.
(Other embodiments)
As mentioned above, although embodiment of this invention was described, the scope of the present invention is not limited only to the said embodiment, The various form which can implement | achieve the function of each invention specific matter of this invention is included. It is.

  For example, in the above-described embodiment, as the ground contact control, feedback control is performed in which the stroke of the lower wheel is continuously extended while the vehicle body is tilted so that the vehicle body is kept horizontal. However, in order to reduce not only such feedback control but also the inclination of the vehicle body, any control is used as the ground control as long as the lower wheel stroke due to the inclination is longer than the reference length. May be. Further, in order to reduce the inclination of the vehicle body, any control may be used as the ground contact control as long as the stroke of the wheel positioned on the upper side by the inclination is shorter than the reference length.

  Further, the determination in step 130 is not necessarily performed in the ground control calculation unit 15c. In this case, if both the determinations in steps 110 and 120 are affirmative, the ground control is selected. Further, either one of the determinations in steps 110 and 120 may not be performed.

  In addition, the vehicle body lateral direction tilt amount detection unit 15a determines the lateral tilt angle θ of the vehicle 100 based on the vertical acceleration detection value Gz of the vehicle 100, the lateral acceleration detection value Gy of the vehicle 100, It may be calculated based on all or any two of the detected acceleration values Gx in the longitudinal direction.

  Further, in the processing of the unevenness / lateral inclination determination unit 15e shown in FIG. 3, a set of the calculated roll angle Rae and the actual roll angle Raa may be used instead of the set of the calculated lateral acceleration Gye and the actual lateral acceleration Gya. A set of calculated roll angle change rate Rre and actual roll angle change rate Rra may be used.

  The calculated roll angle Rae and the calculated roll angle change rate Rre are estimated values of the roll angle and roll angle change rate estimated based on the steering angle. The calculated roll angle Rae and the actual roll angle change rate Rre can be calculated from the calculated acceleration Gye based on a well-known relational expression determined by the weight of the vehicle, the height of the center of gravity, the suspension characteristics, and the like. The actual roll angle Raa and the actual roll angle change rate Rra can be calculated based on detection values of a roll angle sensor and stroke sensors 5FR, 5FL, 5RR, and 5RL (not shown).

  In addition, in the processing of the unevenness / lateral inclination determination unit 15e, instead of the calculated lateral acceleration Gye and actual lateral acceleration Gya set, the calculated difference between the left wheel and the right wheel (or the rate of change thereof) and the actually measured value (or (Change rate thereof) may be used. The calculated value of the difference between the left and right wheel strokes can be calculated from the calculated roll angle. The calculated change rate of the difference between the left wheel stroke and the right wheel stroke can be calculated from the calculated roll angle change rate.

  Further, the actual measurement value of the difference between the strokes of the left wheel and the right wheel and the rate of change thereof can be calculated based on the detection values of the stroke sensors 5FR, 5FL, 5RR, 5RL.

  The actuators that change the stroke of each wheel are not limited to those described in the above embodiment, and are described in, for example, Patent Document 1, Japanese Patent Application Laid-Open No. 2006-168386, and Japanese Patent Application Laid-Open No. 2005-238971. A stabilizer may be used, or a hydropneumatic suspension, a pneumatic suspension, or the like may be used.

It is a figure which shows the example of mounting of the various apparatuses to the vehicle 100 to which embodiment of this invention is applied. It is a block diagram which subdivides and shows the suspension ECU15 function of 1st Embodiment. It is a flowchart of the process which the unevenness / horizontal inclination determination part 15e performs. It is a graph which shows an example 420 of the time change of the absolute value of calculation lateral acceleration Gye-actual lateral acceleration Gya when vehicles are running on uneven road. It is a flowchart of the process which the selection part 15f performs. FIG. 5 is a schematic diagram showing a state where the ground contact control is not performed in the vehicle 100 traveling on the lateral slope 80. FIG. 3 is a schematic diagram showing a state in which grounding control is performed in a vehicle 100 traveling on a horizontal slope 80. 1 is a schematic diagram showing a vehicle 100 traveling on a bumpy road. It is a block diagram which subdivides and shows the suspension ECU15 function of 2nd, 3 embodiment. It is a flowchart of right-and-left grounding control. It is a flowchart of diagonal grounding control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wheel, 4 ... Stabilizer actuator, 5 ... Stroke sensor,
6 ... wheel speed sensor, 7 ... suspension actuator,
8 ... load sensor, 9 ... steering angle sensor, 11 ... acceleration sensor,
13 ... Manual switch, 14 ... Brake actuator,
15 ... Suspension ECU, 15a ... Vehicle body lateral direction inclination amount detection unit,
15b: body speed detection unit, 15c: ground control calculation unit,
15d: posture control calculation unit, 15e: unevenness / lateral inclination determination unit, 15f: selection unit,
15g: Drive unit, 15h ... Ground load detection unit, 50 ... In-vehicle LAN,
63 ... hollow part, 80 ... lateral ramp, 100 ... vehicle.

Claims (5)

The distance from the first wheel (1FR) and the third wheel (1RR) mounted on the right side toward the traveling direction of the vehicle body to the vehicle body and the first wheel mounted on the left side toward the traveling direction of the vehicle body Wheel-vehicle distance mounted on a vehicle equipped with an actuator (4F, 4R, 7FL, 7FR, 7RL, 7RR) that changes the distance from the second wheel (1FL) and the fourth wheel (1RL) to the vehicle body A control device,
Vehicle body inclination detecting means (15a) for detecting a lateral inclination of the vehicle body relative to a horizontal plane;
In order to reduce the inclination detected by the vehicle body inclination detection means, from the wheels attached to the vehicle body position on the lower side of the right wheel and the left wheel according to the inclination detected by the inclination detection means to the vehicle body Control means (15b-15g) for controlling the actuator so that the distance of the vehicle is longer than the distance between the wheel and the vehicle body when the vehicle is stationary on a horizontal plane. Wheel-body distance control device. The distance from the first wheel (1FR) and the third wheel (1RR) mounted on the right side toward the traveling direction of the vehicle body to the vehicle body and the first wheel mounted on the left side toward the traveling direction of the vehicle body Wheel-vehicle distance mounted on a vehicle equipped with an actuator (4F, 4R, 7FL, 7FR, 7RL, 7RR) that changes the distance from the second wheel (1FL) and the fourth wheel (1RL) to the vehicle body A control device,
Vehicle body inclination detecting means (15a) for detecting a lateral inclination of the vehicle body relative to a horizontal plane;
In order to reduce the inclination detected by the vehicle body inclination detection means, the wheel attached to the vehicle body position on the upper side by the inclination detected by the inclination detection means from the left wheel and the right wheel to the vehicle body. Wheels comprising control means (15b to 15g) for controlling the actuator so that the distance is shorter than the distance between the wheel and the vehicle body when the vehicle is stationary on a horizontal plane. -Vehicle distance control device. Load detecting means for detecting a ground load of each of the first, second, third, and fourth wheels;
A load comparison means for comparing the magnitude relationship of the ground load detected by the load detection means;
A second control means is provided for controlling the actuator so as to increase a distance between the wheel identified as a result of comparison by the load comparing means and being smaller than other wheels and the vehicle body. Item 3. The wheel-vehicle distance control device according to Item 1 or 2. Load detecting means (15h) for detecting the ground load of each of the four wheels,
The control means is further configured to, based on a detection result of the load detection means, a sum of a load of the first wheel and a load of a wheel at a diagonal position with respect to the first wheel, and the second wheel. And the sum of the loads of the wheels in a diagonal position with respect to the second wheel are compared, and at least one of the wheels having the smaller sum is compared with the vehicle body from the wheel. 4. The wheel-vehicle distance control apparatus according to claim 3, wherein the second control means is controlled to increase the distance to the vehicle. The control means determines whether the cause of the lateral acceleration applied to the vehicle body is due to centrifugal force or the inclination of the road surface, and based on the determination that it is due to the inclination of the road surface, The wheel-vehicle body according to any one of claims 1 to 4, wherein the operation of the control means is permitted and the operation of the control means is prohibited based on the determination that the control means is caused by centrifugal force. Distance control device.

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