JP2006298168A - Control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device capable of increasing the braking force or the driving force of a wheel. <P>SOLUTION: The control device performs the first steering operation of steering a wheel 2 by the first angle θ1 in the first steering direction from the initial position P0, and the second steering operation of steering the wheel 2 by the second angle θ2 in the second steering direction opposite to the first steering direction after the first steering operation. The ground contact state between a road surface and the ground contact surface of the wheel 2 is improved thereby, and the braking force or the driving force of the wheel 2 can be increased. For example, when a vehicle travels on a snowy road, a water film generated between the road surface and the ground contact surface of the wheel 2 can be extruded to the outside by steering the wheel 2 in the right-to-left direction. Thus, the degree of contact of the road surface with the ground contact surface of the wheel 2 can be enhanced, and the braking force or the driving force can be increased, accordingly. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a control device that controls a steering operation of a wheel by operating an actuator device with respect to a vehicle having a wheel configured to be steerable and an actuator device that drives and drives the wheel. The present invention relates to a control device capable of improving braking force or driving force.

  For example, anti-lock control and traction control control exist as techniques for controlling the wheels to increase the braking force and driving force. In a conventional example of anti-lock control, the braking force of a wheel caused by an excessive brake operating force (for example, brake pressure) is controlled by controlling the slip ratio of the wheel during braking of the vehicle to avoid wheel locking. Is prevented (for example, Patent Document 1).

Further, in a conventional example of traction control technology, in a structure in which driving force is transmitted to left and right wheels (drive wheels) via a differential mechanism, when one of the drive wheels slips, the slipping drive wheel To prevent the drive torque from being transmitted to the other drive wheel (for example, Patent Document 2).
JP-A-5-155325 JP 2004-123084 A

  However, the technique of improving the braking force or the driving force by suppressing the wheel slip as in the conventional technique described above has a problem that the improvement of the braking force or the driving force is limited. That is, since the braking force or the driving force depends on the road surface state (for example, the friction coefficient μ) on which the wheel travels, the conventional technology cannot exceed the maximum value of the braking force or the driving force determined by the road surface state.

  The present invention was made in order to provide a new method related to wheel control technology against the background described above, and provides a control device capable of improving the braking force or driving force of a wheel. It is an object.

  In order to achieve this object, the control device according to claim 1 operates the actuator device for a vehicle having a wheel configured to be steerable and an actuator device for steering and driving the wheel. A steering operation of a wheel, wherein the actuator device is operated to steer the wheel by a first angle in a first steering direction; and after the first steering operation, Actuator actuating means is provided for executing a second steering operation for steering by a second angle in a second steering direction which is opposite to the first steering direction.

  According to a second aspect of the present invention, there is provided a control device according to the first aspect, further comprising: a brake determining unit that determines whether or not the wheel is in a braking state, and the actuator actuating unit is controlled by the brake determining unit. Is determined to be in a braking state, the actuator device is operated.

  The control device according to claim 3 is the control device according to claim 1 or 2, wherein ground speed detection means for detecting the ground speed of the vehicle, rotation speed detection means for detecting the rotation speed of the wheels, and Slip ratio calculating means for calculating the slip ratio of the wheel based on the ground speed and the rotational speed detected by the ground speed detecting means and the rotational speed detecting means, and a slip area for storing a slip ratio corresponding to the slip area of the wheel Storage means, and state determination means for determining whether or not the wheel is in the slip area based on the slip ratio stored in the slip area storage means and the slip ratio calculated by the slip ratio calculation means. The actuator actuating means is configured to actuate the actuator when the state judging means judges that the wheel is in a slip region. To operate the over data devices.

  A control device according to a fourth aspect is the control device according to the third aspect, further comprising angle determining means for determining the first and second angles, respectively, and the angle determining means is calculated by the slip ratio calculating means. The first and second angles are determined based on the value of the slip ratio of the wheel.

  According to a fifth aspect of the present invention, there is provided the control device according to the third aspect, further comprising time determining means for respectively determining times required for the first and second steering operations, wherein the time determining means is configured to detect the ground speed. The time required for the first and second steering operations is determined based on at least one of the value of the ground speed of the vehicle detected by the means and the value of the slip ratio of the wheels calculated by the slip ratio calculating means. .

  A control device according to a sixth aspect is the control device according to any one of the first to fifth aspects, wherein the vehicle includes a plurality of the wheels, and the actuator device is capable of independently driving the plurality of wheels. The actuator actuating means is configured to actuate the actuator device so that the first and second steering operations are performed independently for each of the plurality of wheels.

  The control device according to claim 7 controls the steering operation of the wheel by operating the actuator device with respect to a vehicle having a wheel configured to be steerable and an actuator device for steering and driving the wheel. And a state determination unit that determines whether or not the wheel is in a slip region, and a driver for steering the wheel when the state determination unit determines that the wheel is in a slip region. Regardless of the operation state of the operation unit operated by the control unit, when the actuator device is operated and the wheel is steered, and the state determination unit determines that the wheel is not in the slip region. The wheel steered by the first actuator actuating means is steered to a steering position corresponding to the operation state of the operation unit. And a second actuator operation means for operating the actuator device.

  According to the control device of the first aspect, the actuator can be steered by including the actuator operating means and operating the actuator device by the actuator operating means. Thus, by steering the wheel, there is an effect that the ground contact state between the road surface and the ground contact surface of the wheel can be improved, and the braking force or drive force of the wheel can be improved.

  That is, according to the present invention, by steering the wheel, an object on the road surface that hinders braking or driving can be pushed outside from between the road surface and the ground contact surface of the wheel. The degree of contact with the ground contact surface of the wheel can be increased (the ground contact state can be improved), and the braking force or driving force can be improved.

  As a specific example, for example, a case of traveling on a snowy road is exemplified. In this case, since the water film generated between the road surface and the ground contact surface of the wheel can be pushed outside by steering the wheel, the degree of adhesion between the road surface and the ground contact surface of the wheel is increased, Accordingly, the braking force or driving force can be improved.

  In addition, according to the present invention, by steering the wheel, the surface of the road surface can be destroyed to expose a new road surface, and the ground contact surface of the wheel can be brought into contact with a fresh road surface. It is possible to increase the degree of contact with the ground contact surface of the wheel (improve the ground contact state) and improve the braking force or driving force.

  As a specific example, for example, a case of traveling on an unpaved road surface is exemplified. In this case, by steering the wheel, the unevenness of the road surface can be destroyed and a new road surface can be exposed from the lower layer, or the road surface can be leveled. The degree of adhesion can be increased, and the braking force or driving force can be improved accordingly.

  Further, according to the present invention, by steering the wheel, the contact surface of the wheel can be deformed in the steering direction, and the contact area with the road surface can be increased (improvement of the contact state). The power or driving force can be improved.

  Furthermore, according to the present invention, as described above, by steering the wheel, an object on the road surface can be pushed outside from between the road surface and the ground contact surface of the wheel. Since a resistance force for pushing is generated, the resistance force can be used as a braking force or a driving force, and the braking force or the driving force can be improved accordingly.

  According to the control device of the second aspect, in addition to the effect produced by the control device of the first aspect, the brake determination means for determining whether or not the wheel is in a braking state is provided, and the wheel is braked by the brake determination means. When it is determined that the actuator is in a state, the actuator actuating means activates the actuator device, that is, when the wheel is in a braking state, the wheel is steered in the first direction and the second direction, and the road surface and the ground contact surface of the wheel As a result, the braking force of the wheels can be efficiently improved.

  In this case, it is not necessary to determine whether or not the wheel is in the slip region, and the processing can be simplified, so that the control load of the control device can be reduced and quick control can be performed. effective.

  According to the control device of the third aspect, in addition to the effect produced by the control device according to the first or second aspect, the slip ratio calculation means for calculating the slip ratio of the wheel, and the slip ratio corresponding to the slip region of the wheel A state for determining whether or not the wheel motion characteristics are in the slip region based on the slip region storage means to be stored, the slip rate stored in the slip region storage means and the slip ratio calculated by the slip ratio calculation means Since the operation of the actuator device by the actuator actuating means is performed when the state judging means judges that the wheel motion characteristic is in the slip region, it is efficient to improve the braking force or driving force of the wheel. There is an effect that can be achieved.

  That is, the fact that the wheel motion characteristics are in a non-slip state means that the braking force or driving force acting on the ground contact surface of the wheel from the road surface increases as the slip ratio increases. Even if the wheel control (steering control) of the invention is not applied, the braking force or driving force of the wheel during acceleration / deceleration can be maximized.

  On the other hand, the fact that the wheel motion characteristics are in the slip state means that the braking force or driving force acting on the ground contact surface of the wheel from the road surface decreases as the slip ratio increases, and this state is applied. When the vehicle is decelerated, the slip ratio further increases, resulting in a decrease in braking force or driving force acting on the ground contact surface of the wheel from the road surface.

  Therefore, as in the present invention, the operation of the actuator device by the actuator operating means is performed when it is determined that the motion characteristic of the wheel is in a slip state, thereby improving the ground contact state between the road surface and the wheel ground contact surface. By improving the wheel grip (transition from the slip state to the non-slip state), it is possible to efficiently improve the braking force or the driving force.

  According to the control device of the fourth aspect, in addition to the effect of the control device of the third aspect, the control device includes angle determination means for determining the first and second angles, respectively, and the angle determination means calculates the slip ratio. Since the first and second angles are determined based on the value of the wheel slip ratio calculated by the means, there is an effect that the braking force or the driving force can be appropriately improved.

  For example, when the value of the wheel slip rate is large, the first and second angles are increased as the value of the wheel slip rate increases based on the knowledge that the wheel grip needs to be largely recovered. By determining, the grip recovery effect can be exhibited more greatly. As a result, there is an effect that the braking force or the driving force can be further improved.

  On the other hand, for example, when determining that the first and second angles become smaller as the value of the wheel slip ratio increases, the value of the slip ratio increases and the behavior of the vehicle becomes unstable. The wheel can be steered at a smaller angle. Thereby, for example, even when the grip of the wheel suddenly recovers from a state in which the slip ratio is large, it is possible to suppress a sudden increase in the turning force of the vehicle to the left and right. There is an effect that the steering control can be safely performed (the braking force or the driving force can be safely exhibited) by making it smaller.

  According to the control device of the fifth aspect, in addition to the effect produced by the control device according to the third aspect, the control device further includes time determining means for determining the time required for the first and second steering operations. The time required for the first and second steering operations is determined based on at least one of the value of the vehicle ground speed detected by the ground speed detection means or the value of the wheel slip ratio calculated by the slip ratio calculation means. Therefore, there is an effect that the braking force or the driving force can be appropriately improved.

  For example, when the value of the ground speed of the vehicle is large (fast), the amount of obstacles on the road surface through which the wheel passes per unit time increases, so that the steering operation of the wheel is performed more per unit time. In addition, based on the knowledge that the operation cycle needs to be a short time, by determining that the time becomes shorter as the value of the ground speed of the vehicle is larger, it is more effective from between the road surface and the ground contact surface of the wheel. Many obstacles can be pushed away, and as a result, the braking force or driving force can be further improved.

  On the other hand, for example, by determining that the time becomes shorter as the value of the slip ratio of the wheel becomes larger, the value of the slip ratio becomes larger, and the wheel becomes shorter as the behavior of the vehicle becomes unstable. It can be steered with. As a result, as the slip ratio value increases, the wheel grip can be recovered in a shorter time (transition from the slip region to the non-slip region), and as a result, the vehicle is shifted earlier in a stable state. There is an effect that can be.

  Further, in the case where it is determined that the time is shortened as the value of the slip ratio of the wheel is larger, in a region where the value of the slip ratio is relatively small, the steering of the wheel is performed over a longer time. Accordingly, there is an effect that the burden of the actuator device and control can be reduced, and the device cost and control cost can be reduced. This is particularly effective when the first and second angles are determined to be larger as the wheel slip ratio is smaller.

  According to the control device of the sixth aspect, in addition to the effect produced by the control device according to any one of the first to fifth aspects, the vehicle includes a plurality of wheels, and the actuator device steers and drives the plurality of wheels independently. The actuator actuating means can actuate the actuator device such that the first and second steering operations are performed independently for each of the plurality of wheels. Normally, when the vehicle is running, the ground contact state between the road surface and the ground contact surface of each wheel is different for each wheel, but even in this case, the ground contact state is appropriately improved for each wheel. There is an effect that it is possible to efficiently improve the braking force or driving force of the vehicle as a whole.

  According to the control device of the seventh aspect, the first actuator operation means is provided, and the wheel can be steered by operating the actuator device by the first actuator operation means. Has the same effect as. That is, by steering the wheel, there is an effect that the ground contact state between the road surface and the ground contact surface of the wheel can be improved, and the braking force or driving force of the wheel can be improved.

  Further, since the first actuator actuating means activates the actuator device when the state judging means determines that the wheel is in the slip region, the same effect as the control device according to claim 4 is obtained. That is, there is an effect that it is possible to efficiently improve the braking force or driving force of the wheels.

  Further, since the first actuator actuating means steers the wheel regardless of the operation state of the operation unit operated by the driver to steer the wheel, it depends on the traveling state (straight traveling or turning) of the vehicle. Without any problem, the grounding state between the road surface and the grounding surface of the wheel can be improved, and the grip of the wheel can be recovered.

  Further, the second actuator actuating means determines that the wheel being steered by the first actuator actuating means corresponds to the operation state of the operation unit by the driver when the state judging means judges that the wheel is not in the slip region. Since the actuator device is operated so as to be steered (returned) to the steering position, there is an effect that the behavior of the vehicle can be stabilized.

  Note that the steering of the wheel by the first actuator actuating means according to claim 7 refers to the time until the steering of the wheel by the second actuator actuating means is started, that is, the state judging means judges that the wheel is in the slip state. On the other hand, the steering of the wheel by the second actuator actuating means means the operation of the operating unit from the steering position when the state judging means judges that the wheel is not slipping. It means an operation of returning to the steering position according to the operation state.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram schematically showing a vehicle 1 on which a control device 100 according to the first embodiment of the present invention is mounted. An arrow FWD in FIG. 1 indicates the forward direction of the vehicle 1. Moreover, in FIG. 1, the state by which the predetermined rudder angle was provided to all the wheels 2 is shown in figure.

  First, a schematic configuration of the vehicle 1 will be described. As shown in FIG. 1, the vehicle 1 includes a vehicle body frame BF, a plurality of (four wheels in this embodiment) wheels 2 supported by the vehicle body frame BF, and wheels that rotate and drive these wheels 2 independently. A drive device 3 and an actuator device 4 for steering and driving each wheel 2 independently are mainly provided.

  In the vehicle 1 according to the present invention, during braking or driving, the control device 100 described later monitors the motion characteristics of the wheels 2 and steers the wheels 2 in a predetermined state (slip region in the present embodiment) left and right. By doing so, the ground contact state between the road surface and the ground contact surface of the wheel 2 is improved, and an improvement in braking force or driving force can be achieved.

  Next, the detailed configuration of each part will be described. As shown in FIG. 1, the wheel 2 includes four wheels, that is, left and right front wheels 2FL and 2FR positioned on the front side in the traveling direction of the vehicle 1 and left and right rear wheels 2RL and 2RR positioned on the rear side in the traveling direction. The front and rear wheels 2FL to 2RR are configured to be steerable by the steering devices 20 and 30.

  The steering devices 20 and 30 are steering devices for steering each wheel 2, and as shown in FIG. 1, a king pin 21 that supports each wheel 2 so as to be swingable, and a knuckle arm (not shown) of each wheel 2. 1) and a transmission mechanism 23 for transmitting the driving force of the actuator device 4 to the tie rod 22 is mainly provided.

  As described above, the actuator device 4 is a steering drive device for independently driving the wheels 2 and includes four actuators (FL to RR actuators 4FL to 4RR) as shown in FIG. It is configured. When the driver operates the handle 51, a part (for example, only the front wheels 2FL and 2FR) or all of the actuator device 4 is driven, and a steering angle corresponding to the operation amount of the handle 51 is given.

  Further, even when the driver does not perform the steering operation, when the wheel 2 transits to the slip region during braking or driving, the actuator device 4 (FL to RR actuator 4FL) corresponding to the wheel 2 is used. ˜4RR) is driven, and the wheel 2 is steered left and right. Thereby, the grounding state between the road surface and the grounding surface of the wheel 2 is improved, and the braking force or driving force is improved.

  Thus, the steering drive of the wheel 2 by the actuator device 4 is caused by the operation of the handle 51, and the braking force or the driving force is improved regardless of whether the steering is performed for the purpose of turning or whether the handle 51 is operated. In this embodiment, the former is referred to as turning control and the latter is referred to as steering control. The details of the steering control will be described later (see FIG. 3).

  Here, in the present embodiment, the FL to RR actuators 4FL to 4RR are constituted by electric motors, and the transmission mechanism portion 23 is constituted by a screw mechanism. When the electric motor is rotated, the rotational motion is converted into a linear motion by the transmission mechanism 23 and transmitted to the tie rod 22. As a result, each wheel 2 is driven to swing around the king pin 21 as a swing center, and a predetermined steering angle is given to each wheel 2.

  The wheel driving device 3 is a rotation driving device for independently rotating and driving each wheel 2, and four electric motors (FL to RR motors 3FL to 3RR) are provided for each wheel 2 as shown in FIG. (Ie, as an in-wheel motor). When the driver operates the accelerator pedal 53, a rotational driving force is applied to each wheel 2 from each wheel driving device 3, and each wheel 2 is rotated at a rotational speed corresponding to the operation amount of the accelerator pedal 53.

  The control device 100 is a control device for controlling each part of the vehicle 1 configured as described above. For example, when the accelerator pedal 53 is operated, the control device 100 performs drive control of the wheel drive device 3. When the handle 51 or the pedals 52 and 53 are operated, drive control (turning control, steering control) of the actuator device 4 is performed.

  Further, as described above, the control device 100 monitors the slip rate of each wheel 2 and, when there is a wheel 2 that has transitioned to the slip region, the actuator device so that the wheel 2 is steered left and right. 4 drive control (steering control) is performed. Here, with reference to FIG. 2, the detailed structure of the control apparatus 100 is demonstrated.

  FIG. 2 is a block diagram showing an electrical configuration of the control device 100. As shown in FIG. 2, the control device 100 includes a CPU 71, a ROM 72, and a RAM 73, which are connected to an input / output port 75 via a bus line 74. A plurality of devices such as the wheel driving device 3 are connected to the input / output port 75.

  The CPU 71 is an arithmetic unit that controls each unit connected by the bus line 74. The ROM 72 is a non-rewritable nonvolatile memory storing a control program executed by the CPU 71 (for example, a flowchart of the steering control process shown in FIG. 3), fixed value data, and the like, and the RAM 73 is an execution of the control program. It is a memory for sometimes storing various data in a rewritable manner.

  Here, as shown in FIG. 2, the ROM 72 is provided with a friction force table 72a and an amplitude angle / operation cycle table 72b. The frictional force table 72a is a table that stores the relationship (see FIG. 4) between the slip rate s of the wheel 2 and the vehicle traveling direction frictional force T, and the CPU 71 determines the wheel 2 based on the content of the frictional force table 72a. Is in the slip region.

  The amplitude angle / operation cycle table 72b is a table that stores the relationship between the slip ratio s of the wheel 2, the amplitude angle θ, and the operation cycle T (see FIG. 5), and the CPU 71 performs a steering control process (FIG. 3) described later. In step (2), the steering angle and the operation cycle when the wheel 2 is steered left and right are determined based on the contents of the amplitude angle / operation cycle table 72b.

  As described above, the wheel drive device 3 is a device for rotationally driving each wheel 2 (see FIG. 1), and includes four FL to RR motors 3FL to 3RR that apply a rotational driving force to each wheel 2. And a drive circuit (not shown) for driving and controlling each of the motors 3FL to 3RR based on a command from the CPU 71.

  Further, as described above, the actuator device 4 is a device for steering and driving each wheel 2, and includes four FL to RR actuators 4FL to 4RR that apply a steering driving force to each wheel 2, and each of these actuators. 4FL to 4RR are provided with a drive circuit (not shown) for driving and controlling based on a command from the CPU 71.

  The steering angle sensor device 31 is a device for detecting the steering angle of each wheel 2 and outputting the detection result to the CPU 71. The four FL to RR steering angles for detecting the steering angle of each wheel 2 respectively. Sensors 31FL to 31RR and a processing circuit (not shown) for processing the detection results of the steering angle sensors 31FL to 31RR and outputting the results to the CPU 71 are provided.

  In this embodiment, each steering angle sensor 31FL to 31RR is provided in each transmission mechanism unit 23, and the transmission mechanism unit 23 detects the number of rotations when the rotational motion is converted into linear motion. It is configured as a rotary angle sensor of the type. Since this rotational speed is proportional to the amount of displacement of the tie rod 22, the CPU 71 can obtain the steering angle of each wheel 2 based on the detection result (the rotational speed) input from the steering angle sensor device 31.

  Here, the rudder angle detected by the rudder angle sensor device 31 is an angle formed by the center line of each wheel 2 and a reference line (both lines not shown) of the vehicle 1 (body frame BF). It is an angle that is determined independently of the direction of travel.

  The vehicle speed sensor device 32 is a device for detecting the ground speed (absolute value and traveling direction) of the vehicle 1 with respect to the road surface and outputting the detection result to the CPU 71, and includes longitudinal and lateral acceleration sensors 32a and 32b. And a processing circuit (not shown) for processing the detection results of the acceleration sensors 32a and 32b and outputting the results to the CPU 71.

  The longitudinal acceleration sensor 32a is a sensor that detects the acceleration in the longitudinal direction (the vertical direction in FIG. 1) of the vehicle 1 (body frame BF), and the lateral acceleration sensor 32b is the lateral direction of the vehicle 1 (body frame BF) ( FIG. 1 is a sensor that detects acceleration in the left-right direction. In the present embodiment, each of the acceleration sensors 32a and 32b is configured as a piezoelectric sensor using a piezoelectric element.

  The CPU 71 time-integrates the detection results (acceleration values) of the respective acceleration sensors 32a and 32b input from the vehicle speed sensor device 32 to calculate speeds in two directions (front and rear and left and right directions), respectively. By synthesizing the components, the ground speed (absolute value and traveling direction) of the vehicle 1 can be obtained.

  The wheel rotation speed sensor device 33 is a device for detecting the rotation speed of each wheel 2 and outputting the detection result to the CPU 71. Four FL to RR rotations for detecting the rotation speed of each wheel 2 respectively. Speed sensors 33FL to 33RR and a processing circuit (not shown) that processes the detection results of the rotational speed sensors 33FL to 33RR and outputs them to the CPU 71 are provided.

  In this embodiment, each rotation sensor 33FL-33RR is provided in each wheel 2, and detects the angular velocity of each wheel 2 as a rotation speed. That is, each rotation sensor 33FL-33RR is an electromagnetic pickup provided with a rotating body that rotates in conjunction with each wheel 2 and a pickup that electromagnetically detects the presence or absence of a large number of teeth formed in the circumferential direction of the rotating body. It is configured as a sensor of the type.

  The CPU 71 can obtain the actual peripheral speed of each wheel 2 from the rotation speed of each wheel 2 input from the wheel rotation speed sensor device 33 and the outer diameter of each wheel 2 stored in the ROM 72 in advance. it can.

  The ground load sensor device 34 is a device for detecting the ground load generated between each wheel 2 and the road surface and outputting the detection result to the CPU 71. The FL detects the ground load of each wheel 2 respectively. To RR load sensors 34FL to 34RR, and a processing circuit (not shown) that processes the detection results of the load sensors 34FL to 34RR and outputs them to the CPU 71.

  In the present embodiment, each of the load sensors 34FL to 34RR is configured as a piezoresistive triaxial load sensor. Each of the load sensors 34FL to 34RR is disposed on a suspension shaft (not shown) of each wheel 2 and detects the above-described ground load in the front-rear direction, the left-right direction, and the vertical direction of the vehicle 1.

  The CPU 71 can obtain the friction coefficient μ of the road surface on the ground contact surface of each wheel 2 from the detection results (ground load) of the load sensors 34FL to 34RR input from the ground load sensor device 34.

  For example, when focusing on the front wheel 2FL, when the loads in the front-rear direction, the left-right direction, and the vertical direction of the vehicle 1 detected by the FL load sensor 34FL are Fx, Fy, and Fz, respectively, they correspond to the ground contact surface of the front wheel 2FL. The friction coefficient μ of the road surface of the portion is calculated by using Fx / Fz as the friction coefficient μx in the traveling direction of the vehicle 1 and Fy / Fz as the friction coefficient μy in the left-right direction of the vehicle 1.

  As another input / output device 35 shown in FIG. 2, for example, in order to detect an operation state (rotation angle, stepping amount, operation speed, etc.) of the handle 51, the brake pedal 52, and the accelerator pedal 53 (all of which refer to FIG. 1). An operation state detection sensor device (not shown) is exemplified.

  Next, the steering control of the present invention will be described with reference to FIGS. As described above, the steering control is a control for steering the wheels 2 to the left and right for the purpose of improving the braking force or the driving force, and the above-mentioned turning for the purpose of turning the vehicle 1. Distinguished from control.

  FIG. 3 is a flowchart showing the steering control process. This process is a process that is repeatedly executed by the CPU 71 (for example, at intervals of 0.5 seconds) while the control device 100 is powered on.

  Regarding the steering control process, the CPU 71 first detects the current ground speed of the vehicle 1 and the rotational speed of each wheel 2 (S1, S2), and based on the detected ground speed and rotational speed, respectively. The slip ratio s of each wheel 2 is calculated (S3).

  As described above, the ground speed of the vehicle 1 is detected by the vehicle speed sensor device 32, and the rotational speed of each wheel 2 is detected by the wheel rotational speed sensor device 33 (both see FIG. 2). , 33 to CPU 71.

  Further, the slip rate s of each wheel 2 is obtained by using the peripheral speed Vrf at the time of free rolling of the wheel 2 and the actual peripheral speed Vr of the wheel 2, and when Vrf> Vr, s = (Vr− Vrf) / Vrf. When Vr> Vrf, s = (Vr−Vrf) / Vr.

  Vrf is a peripheral speed at the time of free rolling of the wheel 2 (that is, assuming that the wheel 2 rolls in a state where no slip occurs between the wheel 2) and Vrf = Vc / cos θ. It is represented by Here, Vc is the ground speed of the vehicle 1, and θ is the slip angle of the wheel 2 (the angle formed by the center line of the wheel 2 and the traveling direction of the vehicle 1).

  Vr is an actual peripheral speed of the wheel 2, and as described above, the rotational speed of the wheel 2 detected by the wheel rotational speed sensor device 33 (see FIG. 2) and the wheel stored in the ROM 72 in advance. It is calculated from the outer diameter of 2.

  After calculating the slip rate s of each wheel 2 in the process of S3, each wheel 2 slips based on the slip rate s and the content of the friction force table 72a (see FIG. 2) provided in the ROM 72. It is determined whether it is in the area (S4). Here, the contents of the friction force table 72a will be described with reference to FIG.

  FIG. 4 is a schematic diagram schematically showing the contents of the friction force table 72a. As shown in FIG. 4, the frictional force table 72a stores the relationship between the slip rate s of the wheel 2 and the vehicle traveling direction frictional force F. The vehicle traveling direction frictional force F is a frictional force in the vehicle traveling direction that acts on the ground contact surface of the wheel 2 from the road surface.

  As shown in FIG. 4, when the slip rate s is in the range from 0 to sb, the vehicle traveling direction frictional force F increases as the slip rate s increases, but in the range where the slip rate s is greater than or equal to sb, slip occurs. As the rate s increases, the vehicle traveling direction frictional force F decreases, and the wheel 2 transitions to the slip region.

  Accordingly, the CPU 71 monitors the slip rate s of each wheel 2 and determines whether or not each wheel 2 is in the slip region by checking whether the slip rate s is equal to or greater than sb. Can do.

  As a result, in the process of S4, when it is determined that none of the wheels 2 are in the slip region, that is, all the wheels 2 are in the non-slip region (S4: No), the slip rate s increases. In addition, the vehicle traveling direction frictional force F (braking force or driving force) is also increasing.

  Therefore, in this case (S4: No), the braking force or driving force of each wheel 2 during acceleration / deceleration can be maximized without applying the steering control of the present invention. The process is skipped and the steering control process is terminated.

  On the other hand, in the process of S4, when it is determined that the wheel 2 in the slip region is also one wheel (S4: Yes), the wheel 2 in the slip region moves in the vehicle traveling direction as the slip rate s increases. This means that the frictional force F (braking force or driving force) is in a reduced state. If acceleration / deceleration is performed in this state, the slip ratio s further increases, and the braking force acting on the ground contact surface of the wheel 2 from the road surface is increased. This leads to a decrease in power or driving force.

  Therefore, in this case (S4: Yes), in order to improve the braking force or driving force of the wheel 2 determined to be in the slip region, the process proceeds from S5 to S7 and the above-described steering control is executed. To do.

  Here, as will be described later, in the steering control, a first steering operation for steering the wheel 2 by the first angle θ1 in the first steering direction, and after the first steering operation, the wheel 2 is moved to the first steering operation. And at least a second steering operation for steering by a second angle θ2 in a second steering direction opposite to the steering direction (see FIG. 7A).

  As a result, the ground contact state between the wheel 2 and the road surface can be improved, and the grip of the wheel 2 can be recovered (transition from the slip state to the non-slip state). As a result, braking force or driving force is improved. Can be achieved.

  In the steering control, the first and second steering operations are performed independently for each of the plurality of wheels 2 (four in this embodiment). Normally, when the vehicle 1 is traveling, the ground contact state between the road surface and the ground contact surface of each wheel 2 is different for each wheel 2. Therefore, if the ground contact state can be improved for each wheel 2. Thus, it is possible to efficiently improve the braking force or driving force of the vehicle 1 as a whole.

  In the steering control, first, the process of S5 and FIG. 6 is executed, and based on the contents of the amplitude angle / operation cycle table 72b (see FIG. 2) provided in the ROM 72, the amplitude angle θ and the operation cycle T of the wheel 2 are determined. To decide. Here, the content of the amplitude angle / operation cycle table 72b will be described with reference to FIG.

  FIG. 5 is a schematic diagram schematically showing the contents of the amplitude angle / operation cycle table 72b. In the amplitude angle / operation cycle table 72b, the amplitude angle θ and the operation cycle T are stored in association with the slip ratio s of the wheel 2 and the ground speed of the vehicle 1, respectively. FIG. 5 shows a case where the amplitude angle / operation cycle table 72b is divided into three rows and three columns and nine sections with equal vertical and horizontal intervals for easy understanding.

  For example, if the minimum value sb of the slip rate s is 0.25 (that is, the steering control is performed when the slip rate s is greater than or equal to sb), the lower row in FIG. 5 and the range below 0.5, the middle row in FIG. 5 has a slip ratio s of 0.5 or more and less than 0.75, and the upper row in FIG. Each range of 1 or less is represented.

  Similarly, for example, if the ground speed range for steering control is 0 km / h to 100 km / h, the left column in FIG. 5 shows the range where the ground speed is 0 km / h and less than 34 km / h, and the middle column in FIG. Represents a range where the ground speed is 34 km / h or more and less than 67 km / h, and the right column of FIG. 5 represents a range where the ground speed is 67 km / h or more and 100 / h or less.

  Further, in the present embodiment, “90 °, 45 °, 10 °” is set to “large, medium, small” of the amplitude angle θ, and “0.20 seconds” is set to “long, medium, short” of the operation cycle T. "0.15 seconds and 0.10 seconds" correspond to each.

  Here, in the present embodiment, the amplitude angle θ is the sum of the first and second angles θ1 and θ2 in the steering control (θ = θ1 + θ2), and the operation cycle T is the first and second steering in the steering control. It is defined as the total value of the times T1 and T2 required for the operation. Also. The absolute values of the first and second angles θ1 and θ2 are equal to each other, and the times T1 and T2 required for the first and second steering operations are also equal to each other.

  Therefore, in the present embodiment, when the amplitude angle θ is “large (or medium, small)”, the first and second angles θ1 and θ2 are “θ1 = θ2 = 45 ° (or 22.5 °, 5 °) ”. Similarly, when the operation cycle T is “long (or medium, short)”, the times T1 and T2 are “T1 = T2 = 0.10 seconds (or 0.075 seconds, 0.05 seconds). ) ”.

  Based on the contents of the amplitude angle / operation cycle table 72b configured as described above, the CPU 71 determines the amplitude angle θ and the operation cycle T in the processing of S5 and S6. That is, the current slip rate s of the wheel 2 has already been calculated in the above-described processing of S3, and the ground speed of the vehicle 1 is detected by the vehicle speed sensor device 32 (see FIG. 2) and input to the CPU 71. ing.

  Therefore, the CPU 71 determines the amplitude angle θ and the operation cycle T corresponding to the current slip ratio s calculated in the process of S3 and the ground speed detected by the vehicle speed sensor device 32 in the amplitude angle / operation cycle table 72b. By reading from the contents, it is possible to determine the amplitude angle θ and the operation period T of each wheel 2 (S5, S6).

  In the present embodiment, when the slip ratio s calculated in the process of S3 is a negative value, the absolute value of the slip ratio s is evaluated. However, a different table (amplitude angle / operation cycle table) may be used depending on whether the value of the slip ratio s is positive (that is, during driving) or negative (that is, during braking).

  Here, in the process of S5, as shown in FIG. 5, the amplitude angle θ (first and second angles θ1, θ2) increases as the slip ratio s of the wheel 2 increases (the slip ratio increases). Determined as a large angle. As shown in FIG. 6 (a), when steering control is performed, the grip recovery effect increases as the amplitude angle θ (that is, the first and second angles θ1, θ2) becomes larger. It is based on the knowledge that.

  That is, when the slip rate s of the wheel 2 is a large value (the slip rate is high), the slip of the wheel 2 with respect to the road surface is more remarkable, and it is difficult to recover the grip of the wheel 2. I can say that. Therefore, in this case, since it is necessary to largely recover the grip, the amplitude angle θ is set to a large angle so that a larger grip recovery effect can be obtained (see FIGS. 5 and 6A).

  On the other hand, in the process of S5, as shown in FIG. 5, the operation period T (time T1, T2) is determined to be shorter as the ground speed of the vehicle 1 is larger. As shown in FIG. 6B, when steering control is performed, the inclination becomes smaller and converges as the operation cycle T (ie, times T1 and T2) becomes shorter. It is based on the knowledge that increases.

  That is, that the ground speed of the vehicle 1 is a large value means that the amount of obstacles on the road surface through which the wheel 2 passes per unit time is large. Therefore, in this case, since it is necessary to push more obstacles between the road surface and the ground contact surface of the wheel 2, the operation cycle T is set to a short time so that more steering operation is performed per unit time. (See FIG. 5 and FIG. 6B).

  When the slip ratio s is a large value (the slip ratio is high) and the ground speed of the vehicle 1 is large, the amplitude angle θ is a large angle, but the operation cycle θ is a short time. Therefore, since the wheel 2 can be returned to the initial position P0 (see FIG. 7A) in a shorter time, even if the grip of the wheel 2 is suddenly recovered, the turning force to the left and right of the vehicle 1 is suddenly increased. It is possible to suppress the rise. As a result, the behavior change of the vehicle 1 can be reduced and the steering control can be performed safely.

  After determining the amplitude angle θ and the operation cycle T of the wheel 2 in the processing of S5 and S6, the process then proceeds to the processing of S7, and the wheel is operated with the amplitude angle θ and the operation cycle T determined in the processing of S5 and S6. 2 is steered left and right (S7), and this steering control process is terminated. Here, with reference to FIG. 7, the operation executed in the process of S7 will be described.

  FIG. 7A is a top view of the wheel 2, and FIGS. 7B and 7C are side views of the wheel 2. In the process of S7, the first and second steering operations described above are executed at the steering angle θ (θ1, θ2) and the operation cycle T (T1, T2).

  That is, as shown in FIG. 7A, first, a first steering operation for steering the wheel 2 from the initial position P0 in the first steering direction (right direction in the present embodiment) by the first angle θ1 is performed. Then, a second steering operation is performed in which the wheel 2 is steered by the second angle θ2 in the second steering direction (the left direction in the present embodiment) that is opposite to the first steering direction. Performed at time T2.

  The initial position P0 corresponds to the direction of the center line of the wheel 2 at a predetermined timing during the processing of S7 (in this embodiment, the timing of starting the processing of S7). That is, when the driver operates the handle 51 for the purpose of turning the vehicle 1 and a predetermined rudder angle is given to the wheel 2 due to the operation of the handle 51, the rudder angle is given. The center line of the wheel 2 in the state is the initial position P0.

  Here, in the present embodiment, a case will be described in which the wheel 2 is steered in the first steering direction and then steered by the second angle θ2 in the second steering direction. However, the steering of the wheel 2 in the second steering direction is not necessarily performed by the second angle θ2, and may be performed by an angle larger than the second angle θ2 (for example, θ2 + α), or The angle may be smaller than the second angle θ2 (for example, θ2-α).

  For example, during the process of S7, when the steering wheel 51 is further operated by the driver and the direction of the center line of the wheel 2 is moved by the angle α from the initial position P0 before at least the second steering operation is completed. The wheel 2 steered by the first steering direction in the first steering direction by the first angle θ1 is moved to the steering position corresponding to the operating state of the handle 51 by the driver (ie, the angle α from the initial position P0). The second steering operation may be performed in the second steering direction by the angle corrected by the angle α (that is, θ2 + α or the angle θ2-α). . Thereby, since steering control can be performed according to the operation state of the handle 51 by the driver, the behavior of the vehicle 1 can be stabilized.

  As described above, since the CPU 71 can obtain the steering angle of each wheel 2 based on the detection result input from the steering angle sensor device 31 (see FIG. 2), at least the second steering operation is performed. By calculating the angle α (that is, the amount of movement from the initial position P0) before completion, the wheel 2 is returned to the control position (ie, the steering position corresponding to the operation state of the handle 51 by the driver). )It can be performed.

  Further, when it is determined that the wheel 2 is in the slip region, regardless of the operation state of the handle 51, a means (first actuator actuating means) for repeatedly executing the steering drive of the wheel 2 and the wheel 2 in the slip region. If it is determined that there is not, the actuator device 4 is moved so that the wheel 2 steered by the first actuator actuating means is steered (returned) to the steering position according to the operation state of the handle 51. Means for actuating (second actuator actuating means) may be provided.

  By executing the process of S7, the ground contact state between the road surface and the ground contact surface of the wheel 2 is improved, and the braking force or drive force of the wheel 2 can be improved. Specifically, for example, when traveling on a snowy road, the water film generated between the road surface and the ground contact surface of the wheel 2 can be pushed outside by steering the wheel 2. The degree of adhesion with the ground contact surface of the wheel 2 can be increased, and the braking force or driving force can be improved accordingly.

  Further, for example, as shown in FIG. 7B, when traveling on a non-paved road surface 60, the unevenness of the road surface 60a is destroyed by steering the wheel 2, and a new road surface 60b is exposed from the lower layer. In other words, since the road surface 60a can be leveled on the flat road surface 60b, the degree of adhesion between the road surface 60b and the ground contact surface of the wheel 2 can be increased, and the braking force or driving force can be improved accordingly. .

  In addition, for example, by steering the wheel 2, the ground contact surface of the wheel 2 can be deformed in the left-right direction (steering direction) and the ground contact area with the road surface can be increased. You can improve your power.

  Further, for example, as shown in FIG. 7C, when an object 80 such as a pebble exists on the road surface 70, the object 80 on the road surface 70 is changed to the road surface 70 by steering the wheel 2 left and right. When pushing away from the ground contact surface of the wheel 2 to the outside, a resistance force for pushing the object 80 can be applied to the wheel 2. Therefore, by using such resistance force as braking force or driving force, the braking force or driving force can be improved accordingly.

  Here, in the process of S7, since only two operations of the first steering operation and the second steering operation are performed, even when the wheels 2 are steered and driven (steering control) while the vehicle 1 is traveling, The left / right turning force generated in the vehicle 1 by the steering drive can be canceled as a whole, and as a result, the behavior of the vehicle 1 can be prevented from becoming unstable during the steering control.

  Further, in this way, by performing control so as to perform only the minimum operation of the above two operations, an unnecessary operation in which the steering drive of the wheel 2 to the left and right is performed even after the grip of the wheel 2 is restored. Can be suppressed.

  That is, in the current processing of S7, even when the grip of the wheel 2 cannot be recovered only by the above two operations (the wheel 2 cannot transition from the slip region to the non-slip region), the steering control processing shown in FIG. Since the control device 100 is repeatedly executed every predetermined time while the power is turned on, the steering drive can be executed again in the next processing of S7. In addition, in this case, since the steering drive is performed based on the slip rate s of the wheel 2 and the ground speed of the vehicle 1 at that time, the grip of the wheel 2 can be recovered more efficiently.

  Note that the number of left and right steering driving of the wheel 2 in the process of S7 is not limited to the two operations of the first steering operation and the second steering operation, and may be smaller than this. Alternatively, it may be a large number of times.

  However, it is preferable that two operations of the first steering operation and the second steering operation are the minimum unit operations, and the minimum unit operations are executed an integer number of times. Here, the integer is 1, 2, 3,. This is because the turning force to the left and right generated in the vehicle 1 can be canceled as a whole by steering and driving the wheels 2, and the behavior of the vehicle 1 during braking or driving can be stabilized.

  Further, the first and second steering directions may be changed in opposite directions every time the process of S7 is executed. Specifically, for example, when the first steering direction (second steering direction) is set to the right direction (left direction) in the first processing of S7, the second processing of S7 is performed. Contrary to the first process, the first steering direction (second steering direction) is set to the left (right direction), and the third process in S7 is the second process. Conversely, the first steering direction (second steering direction) is set to the right direction (left direction). Thereby, stabilization of the behavior of the vehicle 1 at the time of braking or driving can be further improved.

  Next, a second embodiment will be described with reference to FIGS. 3 and 8. In the first embodiment, the amplitude angle θ and the operation cycle T are associated with the slip ratio s of the wheel 2 and the ground speed of the vehicle 1. However, in the second embodiment, the amplitude angle θ and the operation cycle T. Is associated only with the slip ratio s. In addition, the same code | symbol is attached | subjected to the part same as above-described 1st Embodiment, and the description is abbreviate | omitted.

  FIGS. 8A and 8B are diagrams schematically showing the contents of the amplitude angle table and the operation cycle table in the second embodiment, and the amplitude angle table and the operation cycle table are the same as those described above. This corresponds to the amplitude angle / operation cycle table in one embodiment, and is provided in the ROM 72.

  In the second embodiment, when it is determined in the steering control process of FIG. 3 that the wheel 2 is in the slip region (S4: Yes), the amplitude angle θ of the wheel 2 is the amplitude angle table shown in FIG. (S5). In the amplitude angle table, the amplitude angle θ is stored in association with the slip rate s of the wheel 2.

  That is, as shown in FIG. 8A, in the range where the slip rate s is from 0 to sb, the value of the amplitude angle θ is defined as 0, while the range where the slip rate s is greater than or equal to sb (slip region). Then, the amplitude angle θ is linearly decreased from the maximum angle θb (for example, 90 °) to the minimum angle θa (for example, 10 °) as the slip ratio s increases.

  Since the current slip ratio s of the wheel 2 has already been calculated in the process of S3, the CPU 71 determines the wheel slip based on the current slip ratio s calculated in the process of S3 and the contents of the amplitude angle table. A value of two amplitude angles θ (that is, first and second angles θ1, θ2) is determined. When the slip rate s calculated in the process of S3 is a negative value, the absolute value of the slip rate s is evaluated.

  Here, in the process of S5, as shown in FIG. 8 (a), the larger the slip ratio s of the wheel 2, the smaller the amplitude angle θ (first and second angles θ1, θ2) becomes. It is determined. That is, in the slip region, as the slip ratio s increases and the behavior of the vehicle 1 becomes unstable, the steering drive of the wheels 2 to the left and right can be performed at a smaller angle.

  As a result, even when the grip of the wheel 2 suddenly recovers, the turning force of the vehicle 1 to the left and right can be suppressed from rapidly increasing, and the change in behavior of the vehicle 1 can be reduced. Can be done safely.

  In the second embodiment, after the amplitude angle θ of the wheel 2 is determined in the process of S5, the operation cycle T of the wheel 2 is based on the contents of the operation cycle table shown in FIG. Determined. In this operation cycle table, the operation cycle T is stored in association with the slip rate s of the wheel 2.

  That is, as shown in FIG. 8B, in the range where the slip rate s is from 0 to sb, the value of the operation cycle T is defined as 0, while the range where the slip rate s is greater than or equal to sb (slip region). Then, the operating cycle T is linearly decreased from the maximum cycle Tb (for example, 0.2 seconds) to the minimum cycle Ta (for example, 0.10 seconds) by increasing the slip ratio s.

  As in the case of the process of S5, since the current slip ratio s of the wheel 2 has already been calculated in the process of S3 described above, the CPU 71 determines the current slip ratio s calculated in the process of S3. Based on the contents of the operation cycle table, the value of the operation cycle T of the wheel 2 (that is, the times T1 and T2 required for the first and second steering operations) can be determined (S6). When the slip rate s calculated in the process of S3 is a negative value, the absolute value of the slip rate s is evaluated.

  Here, in the process of S6, as shown in FIG. 8B, the greater the slip ratio of the wheel 2, the shorter the operation cycle T (time T1, T2) is determined. That is, in the slip region, the wheel 2 can be steered in a shorter time as the slip ratio s increases and the behavior of the vehicle 1 becomes unstable.

  Thereby, as the slip ratio s increases, the grip of the wheel 2 can be recovered in a shorter time, so that the vehicle 1 can be shifted from an unstable state to a stable state earlier.

  In the flow chart (steering control process) shown in FIG. 3, the process of S7 is performed as the actuator operation means according to claim 1, the process of S1 is performed as the rotation speed detection means as the ground speed detection means according to claim 3. Is the processing of S2, the processing of S3 as the slip rate detection means, the processing of S4 as the state determination means, the processing of S5 as the angle determination means according to claim 4, and the time determination means as claimed in claim 5. The process of S6 corresponds to the process of S4, the process of S4 as the state determination means according to claim 7, and the process of S7 as the first actuator operation means.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  For example, the numerical values given in the above embodiments are merely examples, and other numerical values can naturally be adopted.

  Moreover, although each said embodiment demonstrated the case where the amplitude angle (theta) and the operation period T of the wheel 2 were determined based on both or one of the slip ratio s of the wheel 2, and the ground speed of the vehicle 1 (FIG. 5 and FIG. 8), the present invention is not necessarily limited to this, and it is naturally possible to determine the amplitude angle θ and the operation period T of the wheel 2 based on other state quantities.

  Here, examples of other state quantities include the operating state (operating speed, stepping amount, etc.) of the brake pedal 52 and the accelerator pedal 53, the friction coefficient μ of the road surface, and the like.

  For example, even if the depression amount, slip ratio s, ground speed, etc. of the pedals 52 and 53 are the same, when the operation speed is fast (slow), the amplitude angle θ is made larger (smaller) and activated. You may control to make the period T shorter (longer).

  Alternatively, for example, even when the operation state of each pedal 52, 53, the slip ratio s, the ground speed, etc. are the same, the amplitude angle θ is made larger (smaller) when the road surface friction coefficient μ is small (large). In addition, the operation cycle T may be controlled to be shorter (longer).

  Further, the steering control (the process from S5 to S7) is executed only when the friction coefficient μ of the road surface is equal to or smaller than a predetermined reference value, while the steering control (the process from S5 to S7) is performed when the road surface friction coefficient μ is equal to or greater than the predetermined reference value. You may control so that it may abbreviate | omit.

  These state quantities may be used alone or in combination as a reference value for determining the amplitude angle θ and the operation cycle T. Accordingly, the driver's operation state is accurately reflected in the steering control, so that the operational feeling can be improved and the steering control can be performed in a state where the behavior of the vehicle 1 is further stabilized.

  In each of the above embodiments, the case where the steering control (first and second steering operations) is performed when the wheel 2 is in the slip region has been described (see S4 in FIG. 3), but the present invention is not necessarily limited thereto. Of course, it is possible to perform the steering control based on other criteria.

  Here, as another reference, for example, a case where the reference is whether or not the wheel 2 is in a braking state is exemplified. Specifically, a braking determination unit that determines whether or not the wheel 2 is in a braking state is provided, and steering control is started when the braking determination unit determines that the wheel 2 is in a braking state. . This eliminates the need to determine whether or not the wheel 2 is in the slip region, thereby simplifying the process and reducing the control load on the control device 100 (CPU 71) accordingly. As a result, quick control is possible.

  Whether or not the wheel 2 is in a braking state may be determined based on the acceleration of the vehicle 1 detected by the vehicle speed sensor device 32 (see FIG. 2), or the operation state of the brake pedal 52 may be determined. You may judge based on. Moreover, you may combine the said reference | standard. In other words, the steering control may be started when it is determined that the wheel 2 is in the slip region and is in a braking state.

  Further, in each of the above embodiments, the case where the steering control of each wheel 2 is performed independently has been described. However, the present invention is not necessarily limited to this. For example, the left and right wheels 2 have the same amplitude angle θ and operation cycle T. Or all the wheels 2 may be steered simultaneously with the same amplitude angle θ and operating cycle T. Thereby, the control burden of the control apparatus 100 can be reduced.

  In this case, it is preferable to perform steering control simultaneously with the steering directions of the left and right wheels 2 being opposite to each other so that the left and right wheels 2 are toe-in and toe-out. For example, if the left wheel 2 is steered in the left direction and then steered in the right direction, the right wheel 2 is steered in the right direction and then steered in the left direction. Thereby, by turning the wheel 2 to the left and right, the turning force generated in the vehicle 1 can be canceled as a whole, and the behavior of the vehicle 1 during the steering control can be made more stable.

  In each of the above embodiments, the case where the steering control is performed regardless of whether or not the vehicle 1 is turning is not limited to this. For example, the vehicle 1 travels straight ahead. Alternatively, the steering control may be performed only when the vehicle is present. Thereby, it can suppress that the behavior of the vehicle 1 becomes unstable.

  In each of the above embodiments, the case where the frictional force table 72a is configured to have a relationship between the slip rate s and the vehicle traveling direction frictional force F has been described in order to facilitate understanding. The table 72a (ROM 72) need only store at least the value sb described above.

  The same applies to the amplitude angle table and the operation cycle table in the second embodiment, and it is sufficient that at least the maximum values θb and Tb and the minimum values θa and Ta described above are stored.

  It should be noted that the relationship between the slip rate s and the vehicle traveling direction friction force F in the friction force table 72a varies according to the friction coefficient μ of the portion of the road surface on which the wheel 2 travels corresponding to the ground contact surface of the wheel 2. . Therefore, a plurality of friction force tables 72a corresponding to the friction coefficient μ of the road surface are provided in the ROM 72, and the friction force table 72a to be used is changed according to the friction coefficient μ of the portion corresponding to the ground contact surface of the wheel 2. You may comprise. The friction coefficient μ of the road surface on the ground contact surface of each wheel 2 can be obtained for each wheel 2 from the detection result of the ground load sensor device 34 as described above.

  In each of the above-described embodiments, the case where the absolute values of the first and second angles θ1 and θ2 (see FIG. 7A) are equal to each other has been described. However, the present invention is not necessarily limited to this. It is naturally possible to set the first and second angles θ1 and θ2 to different values. The same applies to the times T1 and T2.

  For example, when the steering angle is given to the wheel 2 in order to turn the vehicle 1, one of the first and second angles θ1 and θ2 is set to a value larger than the other, and the first and second The steering control of the wheel 2 may be performed by the second angles θ1 and θ2. The same applies to the times T1 and T2.

  Further, in each of the above embodiments, the case where the wheel 2 is steered left and right as the steering control has been described, that is, the first and second steering operations (two operations) for steering the wheel 2 to the left and right are the minimum unit operations. However, the present invention is not necessarily limited to this, and it is naturally possible to set the steering operation (one operation) to the left (or right) as the minimum unit operation.

  In the case of repeatedly executing such one operation (minimum unit operation), only the steering operation in the same direction (for example, the left direction) may be repeatedly performed, and different directions (for example, the left direction and the right direction). The steering operation may be repeated alternately or in combination.

  Further, in each of the above embodiments, the case where the actuator device 4 is configured by an electric motor and the transmission mechanism portion 23 is configured by a screw mechanism has been described. However, the present invention is not necessarily limited thereto. A hydraulic / pneumatic cylinder may be used. Thereby, since the transmission mechanism part 23 can be abbreviate | omitted, a structure can be simplified and weight reduction and reduction of component cost can be aimed at.

  In each of the above embodiments, the description of a brake device (for example, a drum brake or a disc brake using frictional force) is omitted. Moreover, the wheel drive device 3 may be configured as a regenerative brake and used as a brake device.

It is the schematic diagram which showed typically the vehicle by which the control apparatus in 1st Embodiment of this invention is mounted. It is the block diagram which showed the electric constitution of the control apparatus. It is a flowchart which shows a steering control process. It is a schematic diagram which illustrates the content of a friction force table typically. It is a schematic diagram which illustrates typically the content of an amplitude angle and an operation period table. (A) is a schematic diagram schematically showing the relationship between the amplitude angle and the grip recovery effect, and (b) is a schematic diagram showing the relationship between the operation cycle and the grip recovery effect. (A) is a top view of a wheel, (b) and (c) are side views of a wheel. (A) The content of the amplitude angle table in 2nd Embodiment, (b) is a schematic diagram which illustrates typically the content of the action | operation period table in 2nd Embodiment, respectively.

Explanation of symbols

100 Control device 1 Vehicle 2 Wheel 2FL Front wheel (wheel, left wheel)
2FR Front wheel (wheel, right wheel)
2RL Rear wheel (wheel, left wheel)
2RR Rear wheel (wheel, right wheel)
4 Actuator device 4FL to 4RR FL to RR actuator (actuator device)
32 Vehicle speed sensor device (ground speed detection means)
32a Longitudinal acceleration sensor (part of ground speed detection means)
32b Horizontal acceleration sensor (part of ground speed detection means)
33 Wheel rotation speed sensor device (rotation speed detection means)
33FL to 33RR FL to RR rotational speed sensor (rotational speed detecting means)
51 Handle (operating part)
72a Friction force table (slip area storage means)
θ1 first angle (or second angle)
θ2 Second angle (or first angle)
T1 time (operation time required for the first or second steering operation)

Claims (7)

A control device for operating the actuator device to control a steering operation of the wheel with respect to a vehicle having a wheel configured to be steerable and an actuator device for steering and driving the wheel,
A first steering operation for operating the actuator device to steer the wheel by a first angle in a first steering direction, and a direction opposite to the first steering direction after the first steering operation. A control device comprising actuator actuation means for performing a second steering operation for steering by a second angle in a second steering direction. Braking determination means for determining whether or not the wheel is in a braking state;
2. The control device according to claim 1, wherein the actuator actuating means actuates the actuator device when the brake determining means determines that the wheel is in a braking state. Ground speed detection means for detecting the ground speed of the vehicle;
Rotation speed detection means for detecting the rotation speed of the wheel;
Slip ratio calculating means for calculating the slip ratio of the wheel based on the ground speed and the rotational speed detected by the ground speed detecting means and the rotational speed detecting means;
Slip area storage means for storing a slip ratio corresponding to the slip area of the wheel;
State determination means for determining whether or not the wheel is in the slip area based on the slip ratio stored in the slip area storage means and the slip ratio calculated by the slip ratio calculation means,
3. The control device according to claim 1, wherein the actuator operation unit operates the actuator device when the state determination unit determines that the wheel is in a slip region. 4. Angle determining means for respectively determining the first and second angles;
4. The control device according to claim 3, wherein the angle determining means determines the first and second angles based on the slip ratio value of the wheel calculated by the slip ratio calculating means. Time determining means for determining the time required for the first and second steering operations, respectively;
The time determination means is based on at least one of a value of the ground speed of the vehicle detected by the ground speed detection means or a value of the slip ratio of the wheels calculated by the slip ratio calculation means. 4. The control device according to claim 3, wherein a time required for the steering operation is determined. The vehicle includes a plurality of the wheels, and the actuator device is configured to be capable of steering and driving the plurality of wheels independently.
6. The actuator according to claim 1, wherein the actuator actuating means actuates the actuator device so that the first and second steering operations are performed independently for each of the plurality of wheels. The control apparatus in any one. A control device for operating the actuator device to control a steering operation of the wheel with respect to a vehicle having a wheel configured to be steerable and an actuator device for steering and driving the wheel,
State determination means for determining whether or not the wheel is in a slip region;
When the state determination means determines that the wheel is in the slip region, the actuator device is operated regardless of the operation state of the operation unit operated by the driver to steer the wheel, and the wheel First actuator actuation means for steering
When the state determination unit determines that the wheel is not in the slip region, the wheel steered by the first actuator operation unit is steered to a steering position corresponding to the operation state of the operation unit. And a second actuator actuating means for actuating the actuator device.

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