JP2010202052A - Wheel position changing device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel position changing device of a vehicle capable of suppressing longitudinal direction vibration of the vehicle when getting over a level difference. <P>SOLUTION: This wheel position changing device includes a wheel unit 300 suspending wheels 390 from a vehicle body 100, a wheel unit moving actuator 350 moving the wheel unit 300 in a horizontal direction in relation to the vehicle body 100 and road surface level difference detection means (a vibration detection sensor 320 and a level difference detection sensor 400) detecting the level difference of a road surface passed by the wheels 390 during traveling. The wheel unit moving actuator 350 moves the wheel unit 300 in a direction for lowering wheel load of the wheels 390 running into the level difference when the level difference is detected by the road surface level difference detection means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle wheel position changing device.

  Patent Document 1 discloses a technique for correcting the driving force of a wheel in a direction to reduce the wheel speed fluctuation of the wheel passing through the step for the purpose of suppressing the longitudinal vibration of the vehicle when the road surface step passes.

JP 2005-20831 A

Since the frequency of the longitudinal vibration of the vehicle when passing through the step is a high frequency of about 50 to 60 Hz, the longitudinal vibration may not be suppressed by the driving force correction disclosed by the above-mentioned Patent Document 1.
An object of the present invention is to provide a vehicle wheel position changing device capable of suppressing the longitudinal vibration of the vehicle when overcoming a step.

  In the present invention, the suspension device is moved in a direction in which the wheel load of the wheel riding on the step decreases.

  Therefore, by reducing the wheel load of the wheel that rides on the step, it is possible to reduce the longitudinal input from the wheel to the vehicle when the wheel rides on the step, and to suppress the longitudinal vibration of the vehicle when overcoming the step.

1 is a configuration diagram of a vehicle to which a wheel position changing device according to a first embodiment is applied. It is a side view which shows the wheel attachment structure of Example 1. FIG. It is a figure which shows the wheel load change method of Example 1. FIG. It is a figure which shows the change direction of the vehicle front-back direction distance of Example 1. FIG. 4 is a time chart showing a change in speed of the wheel unit 300 when riding on a step. It is a block diagram of the vehicle to which the wheel position change apparatus of Example 2 is applied. FIG. 6 is a configuration diagram of a vehicle to which a wheel position changing device according to a third embodiment is applied.

  EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the wheel position change apparatus of the vehicle of this invention is demonstrated based on the Example shown on drawing.

First, the configuration will be described.
[overall structure]
FIG. 1 is a configuration diagram of a vehicle to which the wheel position changing device according to the first embodiment is applied, and four wheel units (suspension devices) 300 are arranged below a vehicle body 100, respectively. In the following description, among the wheel units 300, the wheel 390 of the wheel unit 300 located on the vehicle front side is referred to as a front wheel, and the wheel 390 of the wheel unit 300 located on the vehicle rear side is referred to as a rear wheel.

  The vehicle according to the first embodiment includes a vehicle body 100, a steering angle sensor 110, a steering wheel 120, an accelerator opening sensor 130, an accelerator pedal 140, a brake stroke sensor 150, a brake pedal 160, a wheel unit 300, a wheel unit position sensor 310, and vibration detection. A sensor (road surface step detection means) 320, a drive actuator 330, a steering actuator 340, a wheel unit movement actuator (wheel movement device) 350, a wheel 390, a step detection sensor (road surface step detection means) 400, and a controller 500 are provided.

The steering angle sensor 110 detects the operation amount (steering angle) of the steering wheel 120. The accelerator opening sensor 130 detects the operation amount of the accelerator pedal 140. The brake stroke sensor 150 detects the operation amount of the brake pedal 160.
The wheel unit position sensor 310 detects the position of each wheel unit 300 on the wheel unit moving track.

The vibration detection sensor 320 uses, for example, a G sensor, and detects that the corresponding wheel 390 has climbed the step from the longitudinal vibration of the vehicle.
The drive actuator 330 is provided in each wheel unit 300, and drives the wheel 390. As the drive actuator 330, for example, an in-wheel motor is used.
The steered actuator 340 is provided in each wheel unit 300, and changes the steered angle of the wheel 390. As the steering actuator 340, for example, an electric motor is used.

The wheel unit moving actuator 350 moves each wheel unit 300 along the wheel unit moving track. In the first embodiment, the wheel unit moving track is set to be a horizontal circle centered on the vehicle center of gravity, and each wheel 390 moves independently on one annular track centered on the vehicle center of gravity. Become. The structure for realizing the wheel unit moving track will be described later.
The level difference detection sensor 400 uses, for example, a laser radar, a camera, or the like, and detects a road level difference in front of the own vehicle based on the road surface shape in front of the own vehicle.

  The controller 500 controls the vehicle speed by driving the drive actuator 330 based on signals from the accelerator opening sensor 130 and the brake stroke sensor 150 and the vehicle speed obtained from the wheel speed. Further, the steering actuator 340 is driven according to the signal from the steering angle sensor 110 to control the traveling direction of the vehicle.

  Further, when the controller 500 detects that the wheel 390 has climbed a step by the vibration detection sensor 320, or detects a step in front of the vehicle by the step detection sensor 400, the controller 500 detects the vehicle generated when the wheel 390 climbs the step. In order to suppress longitudinal vibration, the wheel unit moving actuator 350 is driven to change the position of each wheel. This wheel position change logic will be described later.

[Wheel mounting structure]
FIG. 2 is a side view showing the wheel mounting structure of the first embodiment.
The wheel side support end 600 a of the suspension frame 600 supports the wheel 390. A bearing 610 is provided on the bottom surface of the vehicle body 100 (or the bottom surface of another suspension frame), and the vehicle body side support end 600b of the suspension frame 600 is rotatably supported with respect to the vehicle body 100.

  The suspension arm 650 for suspending the wheel 390 is supported by the linear motor slider 615 provided in an annular shape along the center of the side surface of the vehicle body 100 so as to be rotatable relative to the vehicle body 100. The linear motor / slider 615 of the first embodiment corresponds to the wheel unit moving actuator 350 of FIG. 1, and moves the wheel 390 relative to the vehicle body 100 by the thrust in the horizontal direction of the linear motor.

The rod 620 that supports the steered shaft of the wheel 390 has a central portion supported by the suspension frame 600 via the bearing 630 and an upper end portion supported by the suspension arm 650 via the ball joint 640. The suspension arm 650 can rotate in the vertical direction with respect to the suspension frame 600.
The steering wheel 390 is steered by connecting a steering gear 660 to the rod 620 and driving a steering actuator 340 fixed to the suspension frame 600.

[Wheel position change logic]
Hereinafter, the wheel position change logic according to the first embodiment will be described.
(Change wheel load)
FIG. 3 shows a wheel load changing method according to the first embodiment.
When the step is detected by the step detection sensor 400 before the front wheel rides on the step, the controller 500 moves the vehicle front and rear between the vehicle center of gravity M and the front wheel before the front wheel rides on the step, as shown in FIG. The front wheel unit 300 is moved so that the directional distance Lf increases. In this case, the front wheels and the rear wheels are moved toward the vehicle front side with respect to the vehicle body 100. Only the front wheels may be moved forward of the vehicle. In this way, by increasing the distance between the front wheel and the vehicle center of gravity M, the wheel load on the front wheel is reduced, so that the longitudinal input from the step to the front wheel can be reduced.

  Further, when the controller 500 detects that the front wheel has climbed the step by the vibration detection sensor 320 attached to the front wheel unit 300, as shown in FIG. 3 (b), before the rear wheel climbs the step, The rear wheel unit 300 is moved so that the vehicle longitudinal direction distance Lr between the vehicle center of gravity M and the rear wheel is increased. In this case, the front wheels and the rear wheels are moved toward the vehicle rear side with respect to the vehicle body 100. Only the rear wheels may be moved to the vehicle rear side. In this way, by increasing the distance between the rear wheel and the vehicle center of gravity M, the wheel load on the rear wheel is reduced, so that the longitudinal input from the step to the rear wheel can be reduced.

Here, as each wheel unit 300 moves, the wheel load of each wheel and the relative position between the vehicle center of gravity M and each wheel change, so that the vehicle motion characteristics change, and the vehicle behavior is unexpected by the driver. There is a risk of becoming something. Therefore, the controller 500 controls at least one of the drive actuator 330 and the steered actuator 340 so as to cancel the vehicle behavior change accompanying the movement of the wheel unit 300.
In addition, when the driver changes the driving operation input, the controller 500 stops the movement of the wheel unit 300 so that the motion characteristic of the vehicle does not change.

(Changing the vehicle front-rear position of the left and right wheels)
In addition to the wheel load change, the controller 500 changes the distance in the vehicle front-rear direction from the vehicle center of gravity M of the left and right wheels so as to reduce the number of wheels that ride on the steps at the same time. FIG. 4 shows a method for changing the vehicle longitudinal distance.

Here, the difference ΔL in the vehicle front-rear direction distance from the center of gravity of the left and right wheels is the level difference when the left front wheel (right front wheel) rides on the step due to the vibration of the vehicle that occurs when the right front wheel (left front wheel) rides on the step. The distance that can be canceled by input from.
Specifically, let T [SEC] be the period of vibration that occurs when the right front wheel (left front wheel) rides on a step, so that the left front wheel (right front wheel) rides on the step after T / 2 [SEC]. . Therefore, when traveling at a vehicle speed V [m / s], ΔL is determined so as to satisfy the following expression (1).
ΔL = T / 2 × V (1)

As another method, the left front wheel (right front wheel) may ride on the step after the amplitude of vibration generated when the right front wheel (left front wheel) rides on the step.
Specifically, if the time from when the right front wheel (left front wheel) climbs the step to the peak of the vibration amplitude is t, when driving at a vehicle speed V [m / s], the following formula ( ΔL is determined so as to satisfy 2).
ΔL> t × V (2)
For the left and right rear wheels, ΔL is determined by the same method as described above, and the vehicle longitudinal direction position is changed.

  FIG. 5 is a time chart showing changes in the speed of the wheel unit 300 when riding on a step. For example, a case will be described in which the distance Lr between the center of gravity M and the rear wheel is increased by ΔX [m] in order to reduce the wheel load of the rear wheel after the front wheel has climbed the step and before the rear wheel has climbed the step.

Let L [m] be the distance between the wheels when the front wheels have climbed the steps, and V [m / x] the vehicle speed. Assuming that the time from when the front wheel climbs the step to the rear wheel climbs the step is t [sec] and the average rear wheel speed is Vr [m / s], t = L / Vr, ΔX = (V-Vr) Since t, the operation speed of the wheel unit 300 is determined so as to satisfy the following formula (3).
Vr = LV (ΔX + L) (3)
Here, as shown in FIG. 5, when the rear wheel rides on a step, it is desirable that the speed is the same as the vehicle body 100, that is, the same speed as the vehicle speed.

Next, a problem to be solved by the wheel position changing device according to the first embodiment will be described.
In the above-mentioned Patent Document 1, the driving force correction of the motor is performed so that the wheel speed fluctuation of the wheel riding on the step is suppressed. The frequency of the longitudinal vibration of the vehicle when passing through the step is about 50-60 Hz. Because of the high frequency, there are cases where vibration cannot be suppressed by motor driving force correction. In other words, in order to effectively suppress vibrations, it is necessary to improve the responsiveness of the entire transmission system including the shaft, but there is a limit to increasing the shaft rigidity, so the vehicle does not increase the shaft rigidity. There is a need to suppress vibrations in the longitudinal direction.

  On the other hand, in the wheel position changing device of the first embodiment, when a road surface step is detected by the vibration detection sensor 320 or the step detection sensor 400, the controller 500 drives the wheel unit moving actuator 350 and rides on the step. The wheel load is changed so that the wheel unit 300 is moved in the direction in which the wheel load of 390 decreases.

  In other words, by reducing the wheel load of the wheel 390 that rides on the step, the front-rear direction input from the wheel 390 to the vehicle body 100 when the wheel 390 rides on the step can be reduced. Directional vibration can be effectively suppressed.

In addition, the controller 500 changes the vehicle front-rear direction position of the left and right wheels so as to reduce the number of wheels that ride on the steps at the same time. That is, the timing at which the left and right front wheels and the left and right rear wheels ride on the steps is shifted. For example, when the left and right front wheels or the left and right rear wheels ride on the step at the same time, the longitudinal input from both wheels 390 is combined to increase the longitudinal vibration of the vehicle. On the other hand, the increase in the amplitude can be prevented by shifting the timing at which the left and right wheels ride on the steps.
Furthermore, when adjusting the timing at which the left and right wheels ride on the steps, a method of shifting the vibration peak, a method of generating anti-phase vibrations to suppress the vibrations, and the like can be used.

Next, effects of the vehicle wheel position changing device of the first embodiment are listed below.
(1) A wheel unit 300 that suspends the wheel 390 from the vehicle body 100, a wheel unit moving actuator 350 that moves the wheel unit 300 in the horizontal direction with respect to the vehicle body 100, and a road surface step through which the wheel 390 passes during traveling are detected. Road surface step detection means (vibration detection sensor 320, step detection sensor 400), and the wheel unit movement actuator 350, when a step is detected by the road surface step detection means, the wheel load of the wheel 390 riding on the step is detected. The wheel unit 300 is moved in a decreasing direction.

  For this reason, by reducing the wheel load of the wheel 390 that rides on the step, the longitudinal input to the vehicle when the wheel 390 rides on the step can be reduced, and the longitudinal vibration of the vehicle when overcoming the step can be suppressed. In addition, since the driving force required for the wheels 390 to climb over the steps can be reduced, fuel efficiency can be improved.

  (2) The wheel unit moving actuator 350 moves the wheel unit 300 in the direction in which the relative front-rear direction distance between the wheel 390 riding on the step and the vehicle center of gravity M increases. For this reason, the wheel load of the wheel 390 riding on the step can be reduced, and the longitudinal vibration of the vehicle can be suppressed.

  (3) The wheel unit moving actuator 350 moves the wheel unit 300 in a direction in which the number of wheels 390 that ride on the step simultaneously decreases. For this reason, the front-rear direction input to the vehicle can be reduced by an amount corresponding to a reduction in the number of wheels 390 that ride on the step.

  (4) The wheel unit moving actuator 350 detects the longitudinal vibration of the vehicle that occurs when one of the left and right wheels 390 passes through the step, and then when the other wheel 390 that passes through the step passes through the step. The wheel unit 300 is moved so as to cancel out the generated longitudinal vibration of the vehicle. For this reason, the amplitude of the longitudinal vibration of the vehicle can be reduced.

  (5) The wheel unit moving actuator 350 is arranged so that the left and right wheel 390 rides on the step after the amplitude of the longitudinal vibration of the vehicle when the left and right wheel 390 passes the step exceeds the peak. Move. For this reason, it is possible to prevent the amplitude of the longitudinal vibration from increasing due to the combination of the input from the left and right wheels 390 and the input from the left and right wheels 390.

  (6) The road surface level difference detection means includes a vibration detection sensor 320 that detects a level difference based on the longitudinal vibration of the vehicle. For this reason, a step can be detected by using a commonly used G sensor, and the cost can be reduced.

  (7) The road surface step detection means includes a step detection sensor 400 that detects a step based on the road surface shape in front of the host vehicle. Therefore, the step can be detected before the front wheel rides on the step.

  (8) The wheel unit moving actuator 350 moves the wheel unit 300 by the required amount of movement before the wheel 390 climbs the step based on the vehicle speed, the distance between the vehicle and the step and the necessary amount of movement of the wheel unit 300. The moving speed of the wheel unit 300 is determined. For this reason, regardless of the vehicle speed, the wheel load of the wheel 390 can be reduced before the wheel 390 climbs the step.

  (9) The wheel unit moving actuator 350 determines the moving speed of the wheel unit 300 so that the wheel speed of the wheel 390 when the wheel 390 rides on the step matches the vehicle speed. For this reason, it is possible to prevent an increase in the front-rear direction input from the step due to excessive wheel speed and an unintended increase in the distance between the vehicle center of gravity M and the wheel 390 after climbing the step due to insufficient wheel speed.

  (10) If the road surface step detecting means detects the next step before the rear wheel climbs on the step, the wheel unit moving actuator 350 determines the distance between the rear wheel and the step, the distance between the front wheel and the next step, and the wheel. Based on the maximum value of the operating speed of the unit 300, the wheel unit 300 is moved so that the sum of the wheel loads of the front wheels when passing the next step and the sum of the wheel loads of the rear wheels when passing the step are minimized. For this reason, even when the steps are continuous, the maximum value of the wheel load of the wheel 390 riding on the steps can be reduced, and the peak of the amplitude of the longitudinal vibration can be suppressed.

  (11) At least one of the braking / driving force or the turning angle of each wheel 390 is changed in a direction to cancel the change in the motion characteristic of the vehicle due to the movement of the wheel unit 300. For this reason, the fluctuation | variation of a vehicle behavior characteristic can be suppressed and the vehicle behavior which a driver intends is realizable.

  (12) The wheel unit moving actuator 350 stops the operation of the wheel unit 300 when detecting a change in the driving operation input of the driver. For this reason, the fluctuation | variation of the vehicle behavior accompanying a wheel position change can be suppressed in the transient state in which the driving operation input of a driver changes.

  FIG. 6 is a configuration diagram of a vehicle to which the wheel position changing device according to the second embodiment is applied. In the second embodiment, each wheel 390 is supported by one chassis unit 700. The chassis unit 700 can move relative to the vehicle body 100. The chassis moving actuator 710 moves the chassis unit 700 relative to the vehicle body 100. The chassis moving actuator 710 is driven and controlled by the controller 500. The chassis unit 700 includes one vibration detection sensor 320 and one step detection sensor 400.

  In the vehicle wheel position changing apparatus according to the second embodiment, when a step is detected by the vibration detection sensor 320 and the step detection sensor 400, the chassis unit 700 is moved in the vehicle front-rear direction with respect to the vehicle body 100, thereby climbing over the step. The wheel load of the wheel 390 can be changed. Since the four wheels 390 are configured to move at the same time, the number of wheels 390 that ride on the step at the same time cannot be reduced, but the number of actuators that move the wheels 390 relative to the first embodiment is reduced to 1/4. Therefore, the cost can be reduced.

FIG. 7 is a configuration diagram of a vehicle to which the wheel position changing device of the third embodiment is applied. In the third embodiment, the position of the front wheel is fixed, and only the rear wheel can be moved relative to the vehicle body 100 by the rear wheel unit 800. It was.
The vibration detection sensor 320 and the step detection sensor 400 according to the third embodiment are disposed in the rear wheel unit 800. The rear wheel movement actuator 810 moves the rear wheel unit 800 relative to the vehicle body 100. The rear wheel movement actuator 810 is driven and controlled by the controller 500. The rear wheel unit 800 includes one vibration detection sensor 320 and one step detection sensor 400.

  In the third embodiment, when a step is detected by the vibration detection sensor 320 and the step detection sensor 400, by moving the rear wheel unit 800 in the vehicle front-rear direction with respect to the vehicle body 100, the wheel load of the wheel 390 riding on the step is increased. Can be changed. Since only the rear wheels are moved, the amount of movement of the rear wheels for changing the wheel load is larger than in the configurations of the first and second embodiments, but the four wheels are moved by one actuator. The rear wheel movement actuator 810 can be made smaller than the second embodiment.

(Other examples)
The best mode for carrying out the present invention has been described above based on the embodiments. However, the specific configuration of the present invention is not limited to the embodiments and is within the scope of the invention. Any design changes are included in the present invention.
For example, the wheel moving device may be configured to move the suspension device in the horizontal direction at least with respect to the vehicle body. For example, a configuration in which the vehicle is moved obliquely with respect to a horizontal plane in the front-rear direction of the vehicle can be applied.

100 body
110 Steering angle sensor
120 Steering wheel
130 Accelerator position sensor
140 Accelerator pedal
150 Brake stroke sensor
160 Brake pedal
300 wheel unit (suspension system)
310 Wheel unit position sensor
320 Vibration detection sensor (road surface level detection means)
330 Drive actuator
340 Steering actuator
350 Wheel unit moving actuator (wheel moving device)
390 wheels
400 Step detection sensor (road surface step detection means)
500 controller
600 suspension frame
600a Wheel side support end
600b Car body side support end
610 bearing
615 Linear motor slider
620 rod
630 bearings
640 Ball joint
650 suspension arm
660 steering gear
700 chassis units
710 Chassis movement actuator
800 Rear wheel unit
810 Rear wheel actuator

Claims (12)

A suspension device for suspending wheels on the vehicle body;
A wheel moving device for moving the suspension device horizontally with respect to the vehicle body;
Road surface step detecting means for detecting a step of the road surface through which the wheel passes during traveling;
With
The wheel moving device according to claim 1, wherein when the step is detected by the road surface step detecting means, the suspension device is moved in a direction in which the wheel load of the wheel riding on the step decreases. The vehicle wheel position changing device according to claim 1,
The wheel position changing device for a vehicle, wherein the wheel moving device moves the suspension device in a direction in which a relative front-rear direction distance between a wheel riding on a step and a vehicle center of gravity increases. In the vehicle wheel position changing device according to claim 1 or 2,
The vehicle wheel position changing device according to claim 1, wherein the wheel moving device moves the suspension device in a direction in which the number of wheels riding on the step simultaneously decreases. In the vehicle wheel position changing device according to any one of claims 1 to 3,
The wheel moving device cancels the longitudinal vibration of the vehicle generated when the wheel passes through the step, and then cancels the vehicle longitudinal vibration generated when the wheel passing through the step passes the step. A vehicle wheel position changing device for moving a suspension device. In the vehicle wheel position changing device according to any one of claims 1 to 3,
The wheel moving device moves the suspension device so that the next wheel rides on the step after the amplitude of the longitudinal vibration of the vehicle when the wheel passes the step exceeds a peak. Wheel position change device. The vehicle wheel position changing device according to any one of claims 1 to 5,
The vehicle wheel position changing device according to claim 1, wherein the road surface level difference detecting means detects a level difference based on a longitudinal vibration of the vehicle. In the vehicle wheel position changing device according to any one of claims 1 to 6,
The vehicle wheel position changing device according to claim 1, wherein the road surface level difference detecting means detects a level difference based on a road surface shape in front of the host vehicle. In the vehicle wheel position changing device according to any one of claims 1 to 7,
Based on the vehicle speed, the distance between the vehicle and the step, and the required amount of movement of the suspension device, the wheel movement device moves the suspension device by the required amount of movement before the wheel climbs on the step. A wheel position changing device for a vehicle, wherein a moving speed of the suspension device is determined. In the vehicle wheel position changing device according to any one of claims 1 to 8,
The vehicle wheel position changing device according to claim 1, wherein the wheel moving device determines a moving speed of the suspension device so that a wheel speed of the wheel when the wheel climbs on a step matches a vehicle speed. The vehicle wheel position changing device according to any one of claims 1 to 9,
When the road surface step detecting means detects the next step before the rear wheel climbs on the step, the distance between the rear wheel and the step, the distance between the front wheel and the next step, and the suspension device Based on the maximum value of the operating speed, the suspension device is moved so that the sum of the wheel loads of the front wheels when the next step passes and the sum of the wheel loads of the rear wheels when the step passes are minimized. A vehicle wheel position changing device. In the vehicle wheel position changing device according to any one of claims 1 to 10,
A wheel position changing device for a vehicle, wherein at least one of a braking / driving force or a turning angle of each wheel is changed in a direction that cancels a change in vehicle motion characteristics due to the movement of the suspension device. The vehicle wheel position changing device according to any one of claims 1 to 11,
The wheel position changing device for a vehicle, wherein the wheel moving device stops the operation of the suspension device when detecting a change in a driving operation input of a driver.

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