JP2008154346A - Vehicle attitude control device and traveling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an increase in the number of rolls which are generated in a vehicle, even if a steering wheel installed to the vehicle is in steering operation and a steering speed is low. <P>SOLUTION: This traveling device 100 mounted to the vehicle 1 uses a left-side front wheel 2l, a right-side front wheel 2r, a left-side rear wheel 3l and a right-side rear wheel 3r as drive wheels. These drive wheels are driven by a left front-side motor 10l, a right front-side motor 10r, a left rear-side motor 11l and a right rear-side motor 11r, respectively, and can independently be adjusted in drive force between the drive wheels. A vehicle attitude control device 30 mounted to the traveling device 100 sets a roll suppression drive force which generates the moment for suppressing the rolls of the vehicle 1, sets a roll suppression drive force which generates the roll suppression moment according to a steering frequency at the time when the left-side front wheel 2l and the right-side front wheel 2r which are the steering wheels of the vehicle 1 are steered, and drives each drive wheel of the traveling device 100 by using the set roll suppression drive forces. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle attitude control device and a traveling device capable of varying the driving force of each driving wheel between at least a pair of left and right driving wheels.

  When a vehicle such as a passenger car or a truck turns, acceleration in the lateral direction of the vehicle (lateral acceleration) acts on the vehicle and rolls are generated in the vehicle. If the acceleration is excessive, the roll generated in the vehicle becomes large and the vehicle may roll over. In Patent Literature 1, in order to prevent the vehicle from rolling over, it is determined that the vehicle may roll over based on the estimated height of the center of gravity of the vehicle and the lateral acceleration during the turn, and it is determined that the vehicle is likely to roll over. In such a case, a technique is disclosed in which safety measures such as deceleration control are taken in order to avoid vehicle rollover.

JP-A-11-83534, paragraph numbers 0006 to 0009

  By the way, when the steering is performed and the steering speed is high, the roll of the vehicle increases as compared with the case where the steering angle is constant and does not change. However, the technique disclosed in Patent Document 1 There is no mention of steering speed. For this reason, when steering and the steering speed is high, there is a possibility that the determination accuracy regarding the roll of the vehicle is lowered. As a result, the intervention of safety measures such as deceleration control may be delayed and the increase in the roll of the vehicle may not be suppressed.

  Therefore, the present invention has been made in view of the above, and a vehicle attitude control device and a traveling device that can suppress an increase in rolls generated in a vehicle even when steering wheels provided in the vehicle are being steered and the steering speed is high. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, a vehicle attitude control device according to the present invention can travel a vehicle that can vary the driving force of the driving wheels between at least a pair of left and right driving wheels. In the vehicle attitude control device for controlling the device, in order to generate a roll suppression moment that suppresses the roll of the vehicle, the steering wheel of the vehicle generates a roll suppression driving force generated in at least one of the left and right drive wheels. A driving force setting unit that is set according to a steering frequency when steering is performed, and a driving force control unit that applies a driving force to the driving wheel based on the driving force set by the driving force setting unit. It is characterized by.

  In the vehicle attitude control device according to the present invention, since the roll suppression driving force is set according to the steering frequency, an increase in rolls generated in the vehicle even when the steering wheel provided in the vehicle is steering and the steering speed is high. Can be suppressed.

  As in the vehicle attitude control device according to the present invention, in the vehicle attitude control device, the driving force setting unit is obtained from the inertia in the roll direction of the vehicle and the roll stiffness of the vehicle as the steering frequency. The roll suppression driving force may be set using a resonance steering frequency.

  As in the vehicle attitude control device according to the next aspect of the present invention, in the vehicle attitude control device, the driving force setting unit uses the resonance steering frequency until the predetermined time elapses. After obtaining the restraining driving force and the predetermined time has elapsed, the roll is determined using the steering frequency obtained based on the ratio of the actual steering angle and the acceleration of the steering angle obtained from the actual steering angle. The suppression driving force may be obtained.

  As in the vehicle attitude control device according to the present invention, in the vehicle attitude control device, the driving force setting unit includes an acceleration of a steering angle obtained from an actual steering angle of the vehicle, and an actual steering of the vehicle. It is preferable to obtain the steering frequency based on the ratio to the angle.

  As in the vehicle attitude control device according to the next aspect of the present invention, in the vehicle attitude control device, the driving force setting unit sets a reference driving force necessary for setting the roll angle of the vehicle to a predetermined target roll angle. The roll suppression driving force may be set by determining and correcting the reference driving force based on a correction value corresponding to the steering frequency.

  As in the vehicle attitude control device according to the next aspect of the present invention, the vehicle attitude control device includes roll angle detection means for detecting the roll angle of the vehicle, and the driving force control unit includes a predetermined roll angle detection means. When the roll angle of the vehicle exceeding the threshold is detected, the roll suppression driving force may be applied.

  As in the vehicle attitude control device according to the next invention, in the vehicle attitude control device, the roll angle is calculated based on the total mass of the vehicle, the center of gravity of the vehicle determined based on the total mass of the vehicle, It is preferable to obtain it based on the lateral acceleration acting on the vehicle.

  A travel device according to the present invention is a travel device for a vehicle that can vary the driving force of the drive wheel between at least a pair of left and right drive wheels, and a roll restraining moment that suppresses the roll of the vehicle. The roll suppression driving force to be generated is set according to a steering frequency when the steering wheel of the vehicle is steered, and the left and right driving wheels are driven by the set roll suppression driving force.

  In the traveling device according to the present invention, since the roll suppression driving force is set according to the steering frequency, even if the steering wheel provided in the vehicle is being steered and the steering speed is high, an increase in the roll generated in the vehicle is suppressed. it can.

  As in the traveling device according to the next aspect of the present invention, in the traveling device, the roll suppression driving force is obtained using a resonance steering frequency obtained from inertia in the roll direction of the vehicle and roll stiffness of the vehicle as the steering frequency. May be set.

  As in the traveling device according to the present invention, in the traveling device, until the predetermined time elapses, the roll suppression driving force is set using the resonance steering frequency, and the predetermined time is reached. After the time elapses, the roll suppression driving force may be obtained using the steering frequency obtained based on the ratio of the actual steering angle of the vehicle and the acceleration of the steering angle obtained from the actual steering angle. Good.

  As in the traveling device according to the present invention, in the traveling device, the steering frequency is based on a ratio between the acceleration of the steering angle obtained from the actual steering angle of the vehicle and the actual steering angle of the vehicle. Is preferably obtained.

  As in the traveling device according to the next aspect of the present invention, in the traveling device, the reference driving force necessary for setting the roll angle of the vehicle to a predetermined target roll angle is based on a correction value corresponding to the steering frequency. The roll suppression driving force may be set by correcting the above.

  As in the travel device according to the present invention, the travel device includes roll angle detection means for detecting a roll angle of the vehicle, and the roll angle detection means detects a roll angle of the vehicle that exceeds a predetermined threshold. If detected, the roll suppression driving force may be applied.

  As in the traveling device according to the next aspect of the present invention, in the traveling device, the total mass of the vehicle, the height of the center of gravity of the vehicle determined based on the total mass of the vehicle, and the lateral acceleration acting on the vehicle It is preferable to determine the roll angle based on this.

  According to the vehicle attitude control device and the traveling device according to the present invention, it is possible to suppress an increase in rolls generated in the vehicle even when the steering wheel provided in the vehicle is being steered and the steering speed is high.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the best mode for carrying out the invention (hereinafter referred to as an embodiment). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  In the following, the case where the present invention is applied to a so-called electric vehicle will be mainly described. However, the application target of the present invention is not limited to this, and it is sufficient that the driving force can be changed between at least a pair of left and right driving wheels. The pair of left and right drive wheels is a combination of left front wheel and right front wheel, left rear wheel and right rear wheel, left front wheel and right rear wheel, left rear wheel and right front wheel, etc. Including. Further, the driving force between at least a pair of left and right driving wheels may independently control the driving force generated by at least a pair of left and right driving wheels, or at least a driving force between at least a pair of left and right driving wheels. The distribution ratio may be controlled.

  In the present embodiment, when at least a pair of left and right driving wheels provided in the vehicle can have different driving forces of the respective driving wheels, the vehicle is controlled according to the steering frequency when the steering wheels of the vehicle are steered. The present invention is characterized in that a roll restraining driving force necessary for restraining the roll is set, and driving wheels of the vehicle are driven with the set roll restraining driving force. Here, when the roll of the vehicle increases, the roll angle of the vehicle and the displacement in the roll direction generated in the vehicle also increase, and when the roll of the vehicle decreases, the roll angle of the vehicle and the displacement in the roll direction generated in the vehicle also decrease. .

  FIG. 1 is a schematic diagram illustrating a configuration of a vehicle including a traveling device according to the present embodiment. FIG. 2 is an explanatory diagram illustrating a configuration example of the front wheel suspension device included in the traveling device according to the present embodiment. FIGS. 3A and 3B are explanatory diagrams illustrating a configuration example of the rear wheel suspension device included in the traveling device according to the present embodiment. In the following description, the distinction between right and left is based on the direction in which the vehicle 1 moves forward (the direction of the arrow X in FIG. 1, the same applies hereinafter). That is, “left” refers to the left side in the direction in which the vehicle 1 moves forward, and “right” refers to the right side in the direction in which the vehicle 1 moves forward. Further, the direction in which the vehicle 1 moves forward is defined as the front, and the direction in which the vehicle 1 moves backward, that is, the direction opposite to the direction in which the vehicle 1 moves forward is defined as the rear.

  The vehicle 1 according to the present embodiment includes a traveling device 100 that uses only an electric motor as a power generation source. The traveling device 100 includes a left front motor 10l, a right front motor 10r, a left rear motor 11l, and a right rear motor 11r that are power generation means. In the present embodiment, the left front motor 10l drives the left front wheel 21, the right front motor 10r drives the right front wheel 2r, the left rear motor 11l drives the left rear wheel 3l, and the right rear motor 11r The rear wheel 3r is driven.

  As described above, in the traveling apparatus 100, the left front wheel 21, the right front wheel 2r, the left rear wheel 31 and the right rear wheel 3r are driven by different electric motors. Thus, in the vehicle 1, all the wheels are drive wheels. That is, the driving wheels of the vehicle 1 are the left front wheel 21, the right front wheel 2r, the left rear wheel 31, and the right rear wheel 3r. The left front wheel 21 and the right front wheel 2r are drive wheels of the vehicle 1 and also function as steering wheels that are steered by the handle 4 to change the traveling direction of the vehicle 1.

  In the traveling device 100, as described above, the left front wheel 21, the right front wheel 2r, the left rear wheel 31 and the right rear wheel 3r are directly driven by different electric motors. The left front motor 101, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r are disposed in the left front wheel 21, the right front wheel 2r, the left rear wheel 31, and the right rear wheel 3r. It has a so-called in-wheel configuration.

  A speed reduction mechanism is provided between the motor and the wheel to reduce the rotational speed of the left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r, and the left front wheel 2l and the right front wheel 2r. The left rear wheel 3l and the right rear wheel 3r may be transmitted. In general, when the electric motor is downsized, the torque decreases, but the torque of the electric motor can be increased by providing a speed reduction mechanism. As a result, the left front motor 101, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r can be reduced in size.

  The left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r are controlled by an ECU (Electronic Control Unit) 50, and the left front wheel 2l, the right front wheel 2r, the left rear wheel 3l, and the right rear wheel. The driving force of the driving force of the wheel 3r is adjusted. In the present embodiment, the total driving force F_all of the traveling device 100, the left front wheel 21, the right front wheel 2r, the left rear wheel 31, and the right rear wheel 3r according to the opening degree of the accelerator 5 detected by the accelerator opening sensor 42. The driving force is controlled.

  In the vehicle attitude control according to the present embodiment, the driving forces of the left front wheel 21, the right front wheel 2r, the left rear wheel 31, and the right rear wheel 3r are changed by the vehicle attitude control device 30 incorporated in the ECU 50. That is, in the vehicle attitude control according to the present embodiment, the vehicle attitude control device 30 exhibits a function as a driving force changing unit that changes the driving force of each driving wheel provided in the vehicle 1. In the present embodiment, the driving force of each of the left front wheel 21, the right front wheel 2r, the left rear wheel 31, and the right rear wheel 3r can be independently controlled by the above-described configuration. Accordingly, the traveling device 100 included in the vehicle 1 according to the present embodiment is configured to be able to vary the driving force of each driving wheel between at least a pair of left and right driving wheels.

  The traveling device 100 included in the vehicle 1 according to the present embodiment controls the driving force of each driving wheel between at least a pair of left and right driving wheels so that the driving reaction force in at least the pair of left and right driving wheels is different. Make it. As a result, a moment (hereinafter referred to as a roll suppression moment) caused by the driving reaction force that suppresses the roll of the vehicle 1 during turning can be generated around the roll axis of the vehicle 1. This will be described later.

  The left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r are rotated by a left front resolver 40l, a right front resolver 40r, a left rear resolver 41l, and a right rear resolver 41r. Is detected. The outputs of the left front resolver 40l, the right front resolver 40r, the left rear resolver 41l, and the right rear resolver 41r are captured by the ECU 50, and the left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear side Used for controlling the electric motor 11r.

  The left front motor 101, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r are connected to the inverter 6. For example, an in-vehicle power source 7 such as a nickel-hydrogen battery or a lead storage battery is connected to the inverter 6, and the left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right are connected via the inverter 6 as necessary. It is supplied to the rear motor 11r. These outputs are controlled by controlling the inverter 6 according to a command from the ECU 50. In the present embodiment, one motor is controlled by one inverter. In order to control the left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r, the inverter 6 includes four inverters corresponding to the respective motors.

  When the left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r are used as power generation sources of the traveling device 100, the electric power of the in-vehicle power supply 7 is supplied via the inverter 6. Further, for example, when the vehicle 1 is decelerated, the left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r function as a generator to perform regenerative power generation, and the recovered energy is used as an in-vehicle power source. Save to 7. This is realized by the ECU 50 controlling the inverter 6 based on a signal such as a brake signal or an accelerator off. In addition, also when performing vehicle attitude control according to the present embodiment, regenerative power generation of the left front motor 101, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r is performed as necessary.

  As shown in FIG. 2, the left front motor 10 l is attached to the front wheel suspension device 8. Accordingly, the left front motor 10 l is attached to the vehicle 1 via the front wheel suspension device 8 and supported by the vehicle 1 by the front wheel suspension device 8. The support structure for the right front motor 10r is the same as the support structure for the left front motor 10l (the same applies hereinafter). Further, as shown in FIG. 3A, the right rear motor 11r is attached to the rear wheel suspension device 9. Accordingly, the right rear motor 11r is attached to the vehicle 1 via the rear wheel suspension device 9 and supported by the vehicle 1 by the rear wheel suspension device 9. The support structure for the left rear motor 11l is the same as the support structure for the right rear motor 11r (the same applies hereinafter). Next, the configuration of the front wheel suspension device 8 and the rear wheel suspension device 9 will be described in more detail with reference to FIGS. 2, 3-1, and 3-2.

  As shown in FIG. 2, in the present embodiment, the so-called strut type is used for the front wheel suspension device 8. An upper mount 20U is provided at one end of the damper 20, and the damper 20 is attached to the vehicle main body 1B via the upper mount 20U. An electric motor fixing bracket 20 </ b> B is provided at the other end of the damper 20. The motor fixing bracket 20B is attached to the motor side bracket 10lb provided in the main body of the left front motor 10l, and fixes the damper 20 and the left front motor 10l. Here, a left front resolver 40l is attached to the drive shaft (motor drive shaft) 10ls of the left front motor 10l as a rotation angle detection means for knowing the rotation angle of the motor drive shaft 10ls. By processing the signal detected by the left front resolver 40l, the rotational speed of the left front motor 10l can be known.

  A pivot portion 10lp is provided at a position symmetrical to the motor side bracket 10lb with respect to the motor drive shaft 10ls. The pivot portion 10lp is combined with the pivot receiver 28 of the transverse link (lower arm) 22 and is pin-coupled. The transverse link 22 is attached to the vehicle main body 1 </ b> B by the vehicle attachment portion 27. Then, the left front motor 10l moves in the vertical direction (Z direction in FIG. 2; the same applies hereinafter), thereby swinging about the swing axis Zsf of the vehicle mounting portion 27. Here, the vertical direction is a direction parallel to the direction of gravity action.

  A front wheel brake rotor 15 and a front wheel wheel 13 are attached to the electric motor drive shaft 10ls. And a tire is attached to the wheel 13 for front wheels, and it becomes the left front wheel 21 (FIG. 1). By the input from the road surface to the left front wheel 21, the front wheel 13 moves in the vertical direction. Since the front wheel wheel 13 is attached to the electric motor drive shaft 10ls, the front wheel wheel 13 operates in the vertical direction, and the left front motor 10l also operates in the vertical direction. Input to the vehicle main body 1 </ b> B due to the left front motor 10 l operating in the vertical direction is absorbed by the spring 20 </ b> S and the damper 20 of the front wheel suspension device 8.

  Since the left front motor 10l and the transverse link 22 are pin-coupled by the pivot portion 10lp and the pivot receiver 28, the transverse link 22 swings about the swing axis Zsf as the left front motor 10l moves up and down. I can exercise. Further, the left front motor 10l is steered together with the front wheel 13 and the tire by the operation of the handle 4. At this time, the pivot portion 10lp rotates while being supported by the pivot receiver 28.

  A front wheel stroke sensor 46 f is attached to the transverse link 22. One end of the front wheel stroke sensor 46f is attached to the vehicle body 1B. When the transverse link 22 moves in the vertical direction by moving the front wheel suspension device 8 in the vertical direction, the front wheel stroke sensor 46f moves in the vertical direction. It expands and contracts. Thus, the operating distance of the left front motor 10l can be detected by the front wheel stroke sensor 46f. The detection signal of the front wheel stroke sensor 46f is taken into the vehicle attitude control device 30 and used for vehicle attitude control according to the present embodiment. In the present embodiment, the right front side of the vehicle 1 (see FIG. 1) is also configured in the same manner as the left front side, and the operating distances of the left front motor 10l and the right front motor 10r can be detected independently. Next, the rear wheel suspension device 9 will be described.

  As shown in FIG. 3A, in the present embodiment, a so-called torsion beam format is used for the rear wheel suspension device 9. The right rear motor 11r is attached to one end of an arm 25 configured integrally with the torsion beam 24. A vehicle mounting portion 26 is provided at the end of the arm 25 on the side opposite to the mounting side of the right rear motor 11r. The arm 25 is attached to the vehicle main body 1 </ b> B via the vehicle attachment portion 26. The arm 25 swings around the swing axis Zsr of the vehicle mounting portion 26. The torsion beam 24 is provided with a spring damper receiver 21. The spring and damper of the rear wheel suspension device 9 are attached between the spring / damper receiver 21 and the vehicle main body 1B. In the present embodiment, the spring and the damper are a spring / damper structure 29 in which both are integrated.

  A right rear resolver 41r is attached to the drive shaft (motor drive shaft) 11rs of the right rear motor 11r as rotation angle detection means for knowing the rotation angle of the motor drive shaft 11rs. By processing the signal detected by the right rear resolver 41r, the rotational speed of the right rear motor 11r can be known. A rear wheel brake rotor 16 and a rear wheel wheel 14 are attached to the motor drive shaft 11rs. And a tire is attached to the wheel 14 for rear wheels, and it becomes the right rear wheel 3r (FIG. 1).

  By the input from the road surface to the right rear wheel 3r, the rear wheel 14 operates in the up and down direction (Z direction in FIG. 3-2, and so on). Since the rear wheel 14 is attached to the motor drive shaft 11rs, the rear wheel 14 operates in the vertical direction, and the right rear motor 11r also operates in the vertical direction. The input to the vehicle main body 1B due to the vertical movement of the right rear motor 11r is transmitted to the spring / damper structure 29 of the rear wheel suspension device 9 via the spring / damper receiver 21 and absorbed therein. The

  As shown in FIG. 3B, a rear wheel stroke sensor 46 r is attached to the arm 25. One end of the rear wheel stroke sensor 46r is attached to the vehicle body 1B. When the rear wheel suspension device 9 operates in the vertical direction and the arm 25 operates in the vertical direction, the rear wheel stroke sensor 46r moves in the vertical direction. Extends and contracts. Thus, the operating distance of the right rear motor 11r can be detected by the rear wheel stroke sensor 46r. The detection signal of the rear wheel stroke sensor 46r is taken into the vehicle attitude control device 30 and used for vehicle attitude control according to the present embodiment. In the present embodiment, the left rear side of the vehicle 1 (see FIG. 1) is configured in the same manner as the right rear side, and the operating distances of the right rear motor 11r and the left rear motor 11l are detected independently. be able to. The front wheel suspension device 8 and the rear wheel suspension device 9 are not limited to the above example, and for example, a multi-link type, a double wishbone type, or other types can be used.

  As in the traveling device 100 according to the present embodiment, in the method in which the left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r, which are power generation means, are fixed to the suspension device, the driving is performed. Of the reaction force, that is, the reaction force component of the driving force of each driving wheel generated by each electric motor, almost all the component in the direction perpendicular to the contact surface of the driving wheel (the vertical direction of the vehicle 1) is input to the suspension device. The For this reason, the moment by the drive reaction force in at least one of the left and right drive wheels can be efficiently generated. Next, another example of the traveling device according to the present embodiment will be described.

  FIGS. 4-1 to 4-4 are explanatory views illustrating modifications of the traveling device according to the present embodiment. The traveling device 100a included in the vehicle 1a shown in FIG. 4A drives the left front wheel 21 by the left front motor 10l, and drives the right front wheel 2r by the right front motor 10r. The left front wheel 21 and the right front wheel 2r can independently control the driving force by the left front motor 10l and the right front motor 10r, respectively. The left rear wheel 3l and the right rear wheel 3r are driven wheels that do not generate a driving force. Even in such a traveling device 100a, the driving force of each driving wheel can be varied between at least a pair of left and right driving wheels.

  The traveling device 100b included in the vehicle 1b shown in FIG. 4B drives the left rear wheel 3l by the left rear motor 11l, and drives the right rear wheel 3r by the right rear motor 11r. The left rear wheel 3l and the right rear wheel 3r can independently control the driving force by the left rear motor 11l and the right rear motor 11r, respectively. The left front wheel 21 and the right front wheel 2r are steering wheels that do not generate a driving force. Even in such a traveling device 100b, the driving force of each driving wheel can be varied between at least a pair of left and right driving wheels.

  The traveling device 100c included in the vehicle 1c shown in FIG. 4C drives the left front wheel 21 by the left front motor 10l and drives the right front wheel 2r by the right front motor 10r. The driving force of the left front wheel 21 and the right front wheel 2r can be independently controlled by the left front motor 10l and the right front motor 10r, respectively. Further, the left rear wheel 3l and the right rear wheel 3r are driven by a driving device 60 having power generation means, but the driving force of the left rear wheel 31 and the driving force of the right rear wheel 3r cannot be controlled independently. Further, it is not possible to provide a difference between the driving force of the left rear wheel 3l and the driving force of the right rear wheel 3r. As described above, in the traveling device 100c, all the wheels (four wheels) serve as driving wheels, but the driving force can be varied only between the left front wheel 21 and the right front wheel 2r. Even in such a traveling device 100c, the driving force of each driving wheel can be varied between at least a pair of left and right driving wheels.

  The traveling device 100d provided in the vehicle 1d shown in FIG. 4D drives the left rear wheel 3l by the left rear motor 11l, and drives the right rear wheel 3r by the right rear motor 11r. The driving force of the left rear wheel 3l and the right rear wheel 3r can be independently controlled by the left rear motor 11l and the right rear motor 11r, respectively. The left front wheel 21 and the right front wheel 2r are driven by a driving device 60 having power generating means, but the driving force of the left front wheel 21 and the driving force of the right front wheel 2r cannot be controlled independently, and the left front wheel It is not possible to provide a difference between the driving force of 2l and the driving force of the right front wheel 2r. As described above, in the traveling device 100d, all the wheels (four wheels) are driving wheels, but the driving force can be varied only between the left rear wheel 3l and the right rear wheel 3r. Even in such a traveling device 100d, the driving force of each driving wheel can be varied between at least a pair of left and right driving wheels.

  In the present embodiment, it is preferable that the responsiveness of the traveling device is high, that is, the time from when the output command is given to the traveling device until the traveling device actually generates the driving force is short. This is because, for example, when fast steering is performed, such as during emergency avoidance, the vehicle's rollover resistance and turning performance can both be achieved more quickly and reliably. Like the traveling device 100 described above, a traveling device that employs an in-wheel motor format is preferable because of its high responsiveness. A traveling device using a hydraulic motor as a power generation source is also preferable because of its high response. Even if the driving force of the left and right driving wheels is changed by adjusting the clutch pressing force, the responsiveness is improved by increasing the hydraulic pressure for operating the clutch, or the responsiveness is not required. It can be used when the driving conditions are such. Next, a method for determining the driving force of each wheel in the vehicle attitude control according to the present embodiment will be described.

  5A and 5B are conceptual diagrams for explaining the vehicle attitude control according to the present embodiment. FIG. 5C is a conceptual diagram illustrating the driving reaction force. FIGS. 5A and 5B show the same vehicle, and both have the instantaneous center of rotation of the suspension system in the wheelbase. FIG. 5C is a vehicle in which the instantaneous rotation center of the suspension device is located in the wheel base.

  In the figure, G is the center of gravity of the vehicle 1, X_roll is the roll axis, h is the height of the center of gravity of the vehicle 1, ORf is the center of instantaneous rotation of the suspension device for the front wheels, ORr is the center of instantaneous rotation of the suspension device for the rear wheels, and hfs is the front wheel. The instantaneous rotation center height of the suspension system for the vehicle, hfr represents the instantaneous rotation center height of the suspension system for the rear wheel, Df represents the tread width of the front wheel, and Dr represents the tread width of the rear wheel. L is the distance between the left front wheel 2l and right front wheel 2r (front wheel side axle) Zf and the left rear wheel 3l and right rear wheel 3r axle (rear wheel side axle) Zr (distance between front and rear axles). , Lf represents the horizontal distance between the center of gravity G and the front wheel side axle Zf, and Lr represents the horizontal distance between the center of gravity G and the rear wheel side axle Zr.

  Note that the instantaneous rotation center is the suspension in a side view of the suspension device, that is, when the suspension device (the front wheel suspension device 8 or the rear wheel suspension device 9) is viewed from the wheel side (the left front wheel 21 or the right rear wheel 3r). This is the instantaneous center of rotation of the device. This is the instantaneous rotation center when the suspension device (front wheel suspension device 8 or rear wheel suspension device 9) is viewed from a direction orthogonal to the traveling direction of the vehicle 1.

  In the vehicle 1 according to this embodiment, the instantaneous rotation center height hfs of the front wheel suspension device and the instantaneous rotation center height hfr of the rear wheel suspension device are lower than the center of gravity height h of the vehicle 1, and the front wheel suspension The instantaneous rotation center ORf of the device and the instantaneous rotation center ORr of the rear wheel suspension are between the front wheel side axle Zf and the rear wheel side axle Zr. Further, in the vehicle 1 according to the present embodiment, the instantaneous rotation center ORf of the front wheel suspension device and the instantaneous rotation center ORr of the rear wheel suspension device are between the front wheel side axle Zf and the rear wheel side axle Zr (that is, the vehicle 1 Between the wheelbases). The positions of the instantaneous rotation center ORf of the front wheel suspension and the instantaneous rotation center ORr of the rear wheel suspension are not limited to the above positions.

  In the vehicle attitude control according to the present embodiment, the driving reaction force is changed by controlling the driving force generated by the driving wheels of the vehicle 1 to suppress the roll of the vehicle 1 (movement around the roll axis X_roll). The driving force of the left front wheel 21 (left front wheel driving force) is Ffl, the driving force of the right front wheel 2r (right front wheel driving force) is Ffr, the driving force of the left rear wheel 3l (left rear wheel driving force) is Frl, and the right rear wheel. The driving force of 3r (right rear wheel driving force) is Frr. Further, the driving reaction force of the left front wheel 21 (left front wheel driving reaction force) is Ffl1, the driving reaction force of the right front wheel 2r (right front wheel driving reaction force) is Ffr1, and the driving reaction force of the left rear wheel 3l (left rear wheel driving reaction force). Force) is Frl1, and the driving reaction force of the right rear wheel 3r (right rear wheel driving reaction force) is Frr1. Here, the driving reaction force is a reaction force component in a direction orthogonal to the ground contact surface (road surface GL) of the driving wheel, among the reaction force components of the driving force in the driving wheels provided in the vehicle 1. On the other hand, it is a force applied in a direction orthogonal to the ground contact surface of the drive wheel.

  When the vehicle 1 turns, a roll moment M_Ay due to the lateral acceleration Ay is generated around the roll axis X_roll of the vehicle 1 (see FIG. 5A). In the example shown in FIG. 5A, the vehicle 1 is turning right, and the roll moment is such that the vehicle 1 is rotated toward the outside in the turning direction (the clockwise roll moment as viewed from the front wheel side of the vehicle 1). That is, a roll moment M_Ay that causes the vehicle 1 to tilt to the left is generated.

  On the other hand, a driving reaction force is generated when the driving wheels of the vehicle 1 generate a driving force. In the left and right driving wheels, at least one of the magnitude or direction of the driving reaction force in at least one of the driving wheels is set to the other. When different from the driving wheels, a moment (moment by driving reaction force) can be generated around the roll axis X_roll of the vehicle 1. In the example shown in FIG. 5A, the driving reaction force Ffl1 of the left front wheel 2l and the driving reaction force Frl1 of the left rear wheel 3l are generated toward the vehicle 1, and the driving reaction force Ffr1 of the right front wheel 2r and the right rear wheel 3r A driving reaction force Frr1 is generated toward the road surface, that is, in a direction opposite to the vehicle 1.

  In this case, since the direction of the driving reaction force between the left and right driving wheels of the vehicle 1 is at least different, a moment M_roll due to the driving reaction force is generated. The moment M_roll due to the driving reaction force is a counterclockwise moment as viewed from the front wheel side of the vehicle 1, that is, a moment that causes the vehicle 1 to tilt toward the right side. The moment M_roll due to the driving reaction force is generated in a direction that cancels the roll moment M_Ay due to the lateral acceleration Ay.

  Thus, a moment is generated by making at least one of the magnitude or direction of the driving reaction force in at least one driving wheel different from that of the other driving wheel between at least a pair of left and right driving wheels. Thereby, it is possible to cancel the roll moment due to the lateral acceleration generated when the vehicle 1 turns. That is, the moment M_roll due to the driving reaction force of at least one of the left and right drive wheels acts as a roll suppression moment that suppresses the roll of the vehicle 1. Hereinafter, the moment due to the driving reaction force of at least one of the left and right driving wheels is referred to as a roll restraining moment M_roll as necessary. The roll suppression moment M_roll can be expressed by using, for example, the difference between the driving reaction force on the left side of the vehicle 1 and the driving reaction force on the right side.

  Here, the driving reaction force will be described with reference to FIG. The driving force is F, the driving reaction force (the component of the driving force F in the direction orthogonal to the road surface GL) is F1, the instantaneous rotation center of the suspension device is OR, the instantaneous rotation center OR of the suspension device and the driving wheel W are grounded to the road surface GL The distance between the grounding portion Q and the road surface GL and the straight line connecting OR and Q is α. The component of the driving force F orthogonal to the straight line connecting OR and Q is F × sin α. Therefore, the clockwise moment by the driving force F around the instantaneous rotation center OR of the suspension device is l × F × sin α. On the other hand, the counterclockwise moment due to the driving reaction force F1 around the instantaneous rotation center OR of the suspension is F1 × l × cos α.

Since the driving wheel W is constrained by the road surface GL and the driving wheel W does not rotate about the instantaneous rotation center OR of the suspension device, l × F × sin α = F1 × l × cos α. If this is solved for the driving reaction force F1 and arranged, the driving reaction force F1 can be expressed by equation (1).
F1 = F × (sin α / cos α) = F × tan α (1)

  That is, the driving reaction force F1 can be obtained by multiplying the driving force F by tan α. Here, since α is a value determined in advance by the design of the suspension device, tan α is a constant, and the driving reaction force F1 is a function of the driving force F. Next, the suppression of the roll by the driving reaction force generated in the driving wheel of the vehicle will be described.

When the lateral acceleration Ay acts on the vehicle 1 shown in FIG. 5A and a roll is generated in the vehicle 1, the roll of the vehicle 1 is caused by the driving reaction force generated due to the driving force of the drive wheels provided in the vehicle 1. A roll restraining moment M_roll is generated around the axis X_roll to restrain the roll of the vehicle 1. When the roll angle of the roll generated in the vehicle 1 due to the lateral acceleration Ay is φ, the relationship of Expression (2) is established between the roll angle φ and the roll suppression moment M_roll. Here, m is the total mass of the vehicle 1, ht is the distance between the center of gravity and the roll center, Kφ is roll rigidity, Iφ is inertia in the roll direction of the vehicle 1 (hereinafter referred to as roll inertia), and Cφ is roll attenuation. ht is a value determined by the difference between the center of gravity height h and the roll center height hroll at the center of gravity. Note that s is a Laplace operator, and the expression (1) is an expression including a transient state. If s = 0, it is a steady state. The same applies to the following.
φ = m × ht × Ay / (Iφs ² + Cφs + Kφ) −M_roll (s) / (Iφs ² + Cφs + Kφ) (2)

  In order to suppress the roll angle generated in the vehicle 1, the target roll angle (hereinafter referred to as target roll angle) φp (s) of the vehicle 1 is smaller than the roll angle currently generated in the vehicle 1. Set to size. Then, the roll suppression moment M_roll obtained by substituting the target roll angle φp (s) into the right side of Formula (2) and solving Formula (1) for the roll suppression moment M_roll is applied to the vehicle 1. As a result, the roll angle φ of the vehicle 1 approaches the target roll angle φp (s), so that the roll of the vehicle 1 is suppressed.

The roll suppression moment M_roll is expressed by, for example, Expression (3) using the driving reaction force Fl (= Ffl1 + Frl1) on the left side of the vehicle 1, the driving reaction force Fr (= Ffr1 + Frr1) on the right side, and the tread D of the vehicle. Can be expressed. Further, the roll restraining moment M_roll can be expressed as in equation (4) using a coefficient Gγ determined from specifications such as the mass and tread of the vehicle 1 and the yaw moment Mγ (s) of the vehicle 1. it can. The yaw moment Mγ (s) changes by changing the driving force of the driving wheels provided in the vehicle 1 between the left and right driving wheels.
M_roll (s) = Fl (s) × D / 2 + Fr (s) × D / 2 (3)
M_roll (s) = Gγ × Mγ (s) (4)

  As described above, the roll suppression moment M_roll (s) may be controlled based on the driving reaction force of the driving wheels provided in the vehicle 1 or may be controlled based on the yaw moment generated in the vehicle 1. In any case, the driving reaction force is adjusted by changing the driving force of the driving wheel provided in the vehicle 1, and the roll restraining moment M_roll is generated. Here, the driving force generated by the driving wheels of the vehicle 1 in order to apply the roll suppression moment M_roll to the vehicle 1 is referred to as a roll suppression driving force.

  FIG. 6 is a conceptual diagram showing the relationship between the steering frequency and the amplitude in the roll direction of the vehicle. 6 represents the steering frequency ω of the left front wheel 21 and the right front wheel 2r, which are the steering wheels of the vehicle 1 shown in FIG. Here, the steering frequency is a frequency when the left front wheel 21 and the right front wheel 2r, which are the steering wheels of the vehicle 1 shown in FIG. 1, are steered, and the steering frequency increases as the steering speed increases. The vertical axis in FIG. 6 is a roll-direction displacement (hereinafter referred to as roll-direction displacement) Y generated in the vehicle 1 when a predetermined lateral acceleration Ay acts on the vehicle 1 shown in FIG. 1 or FIG. . Here, the roll direction displacement Y corresponds to the roll angle φ of the vehicle 1 and the size of the roll generated in the vehicle 1. In FIG. 6, Yc is a roll direction displacement in a steady state of steering such as steady circle turning, and Yt is a roll direction displacement in a steering transient state during the steering.

As shown in FIG. 6, the roll direction displacement Y increases as the steering frequency ω increases, and decreases after the steering frequency is ωn and the roll direction displacement Y becomes maximum. ωn is a resonance steering frequency expressed by the equation (5). Here, as described above, Kφ is the roll rigidity of the vehicle 1 and Iφ is the roll inertia, both of which are determined from the specifications of the vehicle 1. Thus, when the lateral acceleration Ay of a certain magnitude acts on the vehicle 1, the resonance steering frequency is the maximum in the roll direction displacement Y of the vehicle 1, that is, the roll angle of the vehicle 1 and the roll generated in the vehicle 1. Is the maximum steering frequency and is determined from the specifications of the vehicle 1.
ωn = √ (Kφ / Iφ) (5)

  As shown in FIG. 6, when the steering frequency ω increases, the roll direction displacement Y increases in the vicinity of the resonant steering frequency ωn. That is, when the steering wheel of the vehicle 1 shown in FIG. 1 is steered at a high steering speed, a phenomenon that the roll angle of the vehicle 1 increases may occur. This increases the risk of handling and rollover in the vehicle 1. Here, handling / rollover is a rollover phenomenon of the vehicle 1 caused by lateral acceleration acting on the vehicle 1.

  In the present embodiment, the roll suppression moment M_roll is changed in accordance with the steering frequency ω, and the roll direction displacement Y that increases as the resonance steering frequency ωn is approached is suppressed in a transient state of steering. In order to change the roll suppression moment M_roll, the roll suppression driving force generated by the drive wheels provided in the vehicle 1 shown in FIG. 1 or FIG. 5A is changed. That is, in this embodiment, the roll-direction displacement Y is suppressed in a transient state of steering by setting the roll-suppressing driving force generated by the drive wheels provided in the vehicle 1 according to the steering frequency ω. Next, a method for suppressing displacement in the roll direction will be described in detail.

FIG. 7 is an explanatory diagram showing the relationship between the roll direction displacement and the steering frequency. With respect to the lateral acceleration Ay generated in the vehicle 1 shown in FIG. 1 and FIG. 5A, the roll angle φ of the vehicle 1 is expressed by Expression (6).
φ = m × ht × Ay / (Iφs ² + Cφs + Kφ) (6)

  When the turning of the vehicle 1 is in a steady state, even if the vehicle 1 is the same, for example, as the total mass m increases due to an increase in the number of occupants and loads, the roll angle φ increases and the displacement in the roll direction also increases. Become. The straight lines Yc1 and Yc2 in FIG. 7 indicate the roll direction displacement when the vehicle 1 is turning in a steady state. The vehicle 1 is the same for both the straight lines Yc1 and Yc2, but the total mass m of the vehicle 1 is larger in the straight line Yc2 than in the straight line Yc1.

In FIG. 7, the roll angle φ when the turning of the vehicle 1 is in a steady state can be reduced by the steady state correction value Kgy shown in Expression (7).
φ = m × ht × Ay (1−Kgy) / (Iφs ² + Cφs + Kφ) (7)

In order to reduce the roll angle φ when the steering of the vehicle 1 is in a transient state, as shown in the equation (8), the steady state correction value Kgy is multiplied by the transient state correction value Kω set according to the steering frequency ω. The roll angle φ in the transient state is suppressed. Here, Kω> 1.
φ = m × ht × Ay × (1−Kgy × Kω) / (Iφs ² + Cφs + Kφ) (8)

When Expression (8) is transformed into Expression (9) and the Laplace operator s is expressed by ω × j, which is the product of the steering frequency ω and the imaginary unit j, Expression (10) is obtained. When formula (10) is expanded and arranged, formula (11) is obtained.
G (φ / Ay) = {m × ht / (Iφs ² + Cφs + Kφ)} × (1−Kgy × Kω) (9)
G (φ / Ay) = [m × ht / {(Kφ−Iφ × ω ² ) + Cφ × ω × j}] × (1−Kgy × Kω) (10)
G (φ / Ay) = [m × ht / {(Kφ−Iφ × ω ² ) ² + (Cφ × ω) ² }] × √ [{(1-Kgy × Kω) × (Kφ−Iφ × ω ² )} ² + {(1-Kgy × Kω) × Cφ × ω)} ² ] (11)

  Here, when the steering frequency ω is 0, the vehicle 1 turns in a steady state, and the transient state correction value Kω at this time is set to 1. Then, Formula (10) becomes Formula (12). That is, according to the steady state correction value Kgy, when the steering of the vehicle 1 is in a transient state, the roll angle φ of the vehicle 1 becomes a value determined by the equation (12). That is, the roll angle φ of the vehicle 1 is determined by the value of the steady state correction value Kgy and the lateral acceleration Ay acting on the vehicle 1.

For example, when the state of the straight line Yc1 shown in FIG. 7 is set as the reference roll state, when Kgy is set to 0, the roll angle φ of the vehicle 1 does not decrease from the reference roll state, and as a result, the roll direction displacement is Yt1. It remains unchanged. On the other hand, if Kgy is set to 0.5, the roll angle φ of the vehicle 1 becomes ½ of the reference roll state, and the displacement in the roll direction becomes smaller than Yt1. If the total mass m of the vehicle 1 is the smallest, that is, the roll direction displacement when the roll of the vehicle 1 is the smallest is Yt2, and Kgy is set so that the roll direction displacement of the vehicle 1 becomes Yt2. Even when the total mass of the vehicle 1 changes due to changes in the number of occupants and the load, the roll of the vehicle 1 can be minimized.
G (φ / Ay) = m × ht × (1-Kgy) (12)

  When the steering of the vehicle 1 is in a transient state, the steering frequency ω is not zero. In this case, the right side of the equation (11) is assumed to be equal to the right side of the equation (12), and the transient state correction value Kω is obtained by giving the steering frequency ω obtained from the steering operation of the vehicle 1 shown in FIG. That is, the transient state correction value Kω is set so that the roll angle when the steering of the vehicle 1 is in the transient state becomes the roll angle when the turning of the vehicle 1 is in the steady state. When the transient state correction value Kω is set in this way, in FIG. 7, the roll direction displacements Yt1 and Yt2 that increase in the vicinity of the resonance steering frequency ωn in the steering transient state are the roll direction displacements Yc1 and Yc2 in the steady state. Become.

  Using the transient state correction value Kω obtained in this way, the roll suppression moment M_roll shown in Equation (3) or Equation (4) is corrected, and the vehicle 1 is driven with the driving force obtained from the corrected roll suppression moment M_roll_c. When driven, the roll angle of the vehicle 1 in a transient state, that is, during steering, can be set to the roll angle when the turning of the vehicle 1 is in a steady state. As a result, when the steering of the vehicle 1 is in a transient state, the phenomenon that the roll angle of the vehicle 1 increases near the resonance steering frequency ωn can be suppressed, and handling / rollover can be avoided.

  When the transient state correction value Kω is obtained by the above-described method, the center-to-roll center distance determined from the total mass m of the vehicle 1 and the center-of-gravity height h of the vehicle 1 calculated based on the total mass m of the vehicle 1. ht is required. The center-of-gravity height h can be obtained based on the changed total body mass m when the total body mass m changes. The total mass m of the vehicle 1 changes due to changes in the number of passengers and the loading capacity of the vehicle 1, and the center of gravity height h also changes accordingly.

  Therefore, when the total mass m of the vehicle 1 changes due to changes in the number of passengers and the loading capacity of the vehicle 1, a transient state is obtained using the total mass m of the vehicle 1 and the center-to-roll center distance ht after the change. It is preferable to obtain the correction value Kω. As a result, the accuracy of the transient state correction value Kω is further improved, so that the phenomenon that the roll angle of the vehicle 1 increases near the resonance steering frequency ωn can be more effectively suppressed.

  The total mass m of the vehicle 1 is, for example, a front wheel stroke sensor 46f attached to the front wheel suspension device 8 shown in FIG. 2 and a rear wheel stroke sensor 46r attached to the rear wheel suspension device 9 shown in FIG. 3-2. Can be obtained on the basis of the amount of contraction of the suspension device 8 for the front wheel and the suspension device 9 for the rear wheel. That is, the correlation between the total mass m of the vehicle body and the amount of contraction of the front wheel suspension device 8 and the rear wheel suspension device 9 is used. Thus, the front wheel stroke sensor 46f and the rear wheel suspension device 9 function as means for obtaining the total mass of the vehicle.

In order to suppress an increase in the roll angle in the vicinity of the resonance steering frequency ωn when the steering of the vehicle 1 is in a transient state, the steering frequency ω at that time is necessary. Next, a method for obtaining the steering frequency ω will be described. Assuming that the actual steering angle of the steered wheels included in the vehicle 1 shown in FIG. 1 is θ, when steering is in a transient state, the actual steering angle θ is the equation (13), and the steering angular velocity θ ′ is the equation (14). ), The steering angular acceleration θ ″ can be expressed by Equation (15). Here, A is an amplitude and is an arbitrary constant. Further, ω is a steering frequency, and t is time.
θ = A × sin (ω × t) (13)
θ ′ = ω × A × cos (ω × t) (14)
θ ″ = − ω ² × A × sin (ω × t) (15)

By dividing the absolute value | θ ″ | of the steering angular acceleration θ ″ by the absolute value | θ | of the actual steering angle θ from the equations (13) and (15), | θ ″ | / | θ | = | −ω ² × A × sin (ω × t) | / | A × sin (ω × t) | = ω ² Therefore, the steering frequency ω can be obtained based on the ratio between the steering angular acceleration θ ″ obtained from the actual steering angle θ and the actual steering angle θ, as shown in the equation (16).
ω = √ (| θ ″ | / | θ |) (16)

  Here, the steering angle θ can be detected by the steering angle sensor 43 shown in FIG. The steering angular acceleration θ ″ can be obtained by obtaining and calculating the steering angle θ detected by the steering angle sensor 43 by the vehicle attitude control device 30 incorporated in the ECU 50 shown in FIG. That is, the steering angular velocity θ ′ can be obtained from the change in the steering angle θ per unit time, and the steering angular acceleration θ ″ can be obtained from the change in the steering angular velocity θ ′ per unit time. The steering frequency ω can be obtained by giving the steering angular velocity θ ′ and the steering angular acceleration θ ″ obtained in this way to the equation (16).

  FIG. 8 is an explanatory diagram showing the time change of the steering angle and the steering frequency and the time change of the transient state correction value. At t = 0, steering of the steered wheels of the vehicle 1 shown in FIG. 1 starts. As described above, the steering frequency ω is obtained using the steering angle θ and the steering angular acceleration θ ″ calculated from the steering angular velocity θ ′. Therefore, in order to obtain the steering frequency ω, information on at least three steering angles θ is required.

  Actually, in order to ensure the accuracy of the steering frequency ω, some information on the steering angle θ is required. In the example shown in FIG. 8, the time for obtaining the steering angle θ of the amount necessary to ensure the accuracy of the steering frequency ω is t1. After t = t1, the driving force that generates the roll suppression moment M_roll by obtaining the transient state correction value Kω by the above-described method using the steering frequency ω after t = t1 and the equations (11) and (12). Correct. Since the steering operation ends at t = t2, the correction of the roll suppression driving force is ended by setting the transient state correction value Kω = 1. Next, a vehicle attitude control device for realizing vehicle attitude control according to the present embodiment will be described.

  FIG. 9 is an explanatory diagram illustrating a configuration example of the vehicle attitude control device according to the present embodiment. As shown in FIG. 9, the vehicle attitude control device 30 is configured to be incorporated in the ECU 50. The ECU 50 includes a CPU (Central Processing Unit) 50p, a storage unit 50m, an input port 55 and an output port 56, and an input interface 57 and an output interface 58.

  In addition, separately from ECU50, the vehicle attitude | position control apparatus 30 which concerns on this embodiment may be prepared, and this may be connected to ECU50. And in implement | achieving vehicle attitude | position control which concerns on this embodiment, you may comprise so that the said vehicle attitude | position control apparatus 30 can utilize the control function with respect to the traveling apparatus 100 grade | etc., With which ECU50 is provided.

  The vehicle attitude control device 30 includes a control condition determination unit 31, a driving force setting unit 32, and a driving force control unit 33. These are the parts that execute the vehicle attitude control according to the present embodiment. The driving force setting unit 32 and the driving force control unit 33 mainly execute vehicle attitude control according to the present embodiment. In the present embodiment, the vehicle attitude control device 30 is configured as a part of the CPU 50 p that constitutes the ECU 50.

The control condition determination unit 31, the driving force setting unit 32, and the driving force control unit 33 of the vehicle attitude control device 30 are connected via a bus 54 ₁ , a bus 54 ₂ , an input port 55, and an output port 56. . As a result, the control condition determination unit 31, the driving force setting unit 32, and the driving force control unit 33 constituting the vehicle attitude control device 30 can exchange control data with each other or issue commands to one side. Consists of.

Further, a vehicle attitude control device 30 provided in the CPU 50p, and the storage unit 50m, are connected via a bus 54 _3. Thereby, the vehicle attitude control device 30 can acquire the driving control data of the traveling device 100 included in the ECU 50 and use it. Further, the vehicle attitude control device 30 can cause the vehicle attitude control according to the present embodiment to interrupt an operation control routine provided in advance in the ECU 50.

  An input interface 57 is connected to the input port 55. The input interface 57 can detect acceleration in three directions, a left front resolver 40l, a right front resolver 40r, a left rear resolver 41l, a right rear resolver 41r, an accelerator opening sensor 42, a steering angle sensor 43, a vehicle speed sensor 44. Sensors that acquire information necessary for operation control of the traveling device 100, such as a triaxial acceleration sensor 45, a front wheel stroke sensor 46f, and a rear wheel stroke sensor 46r, are connected.

  Signals output from these sensors are converted into signals that can be used by the CPU 50 p by the A / D converter 57 a and the digital input buffer 57 d in the input interface 57 and sent to the input port 55. Thereby, CPU50p can acquire information required for driving control of traveling device 100, and vehicle posture control concerning this embodiment.

An output interface 58 is connected to the output port 56. A control target necessary for vehicle attitude control is connected to the output interface 58. In the present embodiment, the inverter 6 for controlling the left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r is a control target necessary for the vehicle attitude control according to the present embodiment. . The output interface 58 includes control circuits 58 ₁ , 58 _{2 and the} like, and operates the control target based on a control signal calculated by the CPU 50p. With such a configuration, based on the output signals from the sensors, the CPU 50p of the ECU 50 can control the driving forces of the left front motor 101, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r. it can.

  The storage unit 50m stores a computer program including a vehicle attitude control processing procedure according to the present embodiment, a control map, a data map used for the vehicle attitude control according to the present embodiment, and the like. Here, the storage unit 50m can be configured by a volatile memory such as a RAM (Random Access Memory), a nonvolatile memory such as a flash memory, or a combination thereof.

  The computer program may be capable of realizing the vehicle attitude control processing procedure according to the present embodiment in combination with the computer program already recorded in the CPU 50p. The vehicle attitude control device 30 implements the functions of the control condition determination unit 31, the driving force setting unit 32, and the driving force control unit 33 by using dedicated hardware instead of the computer program. Also good. Next, the first vehicle attitude control according to the present embodiment will be described. In the following description, please refer to FIGS.

(First vehicle attitude control)
In the first vehicle attitude control, a roll suppression driving force for suppressing the roll of the vehicle is set according to a steering frequency when the steering wheel of the vehicle is steered, and the drive wheel of the vehicle is set with the set roll suppression driving force. To drive.

  FIG. 10 is a flowchart showing the procedure of the first vehicle attitude control according to the present embodiment. Here, before starting the first vehicle attitude control according to the present embodiment, it is preferable to obtain the total mass m of the vehicle 1 and correct the center-to-roll center distance ht (the same applies to the following examples). In executing the first vehicle attitude control according to the present embodiment, in step S101, the control condition determination unit 31 of the vehicle attitude control device 30 determines whether or not the steering operation has been performed on the vehicle 1 shown in FIG. For example, when the steering angle sensor 43 detects a steering angle of a predetermined amount or more, it is determined that the vehicle 1 has been steered. When it is determined No in step S101, that is, when the control condition determination unit 31 determines that there is no steering operation on the vehicle 1, the process returns to START, and the vehicle attitude control device 30 monitors the driving state of the vehicle 1.

  When it determines with Yes at step S101, ie, when the control condition determination part 31 determines with there being steering operation with respect to the vehicle 1, it progresses to step S102. In step S102, the driving force setting unit 32 of the vehicle attitude control device 30 acquires the steering angle θ of the steering wheel of the vehicle 1 from the steering angle sensor 43 of FIG. 9, and calculates based on the acquired steering angle θ. A steering frequency ω is obtained based on the steering angular acceleration θ ″. Details of the method for obtaining the steering frequency ω of the vehicle 1 are as described above. When the steering frequency ω of the vehicle 1 is obtained, the process proceeds to step S103.

  In step S103, the control condition determination unit 31 compares the steering frequency ω of the vehicle 1 obtained in step S102 with a predetermined steering frequency threshold value (hereinafter referred to as a steering frequency threshold value) ω_c. The steering frequency threshold value ω_c is, for example, a steering frequency when the roll angle of the vehicle 1 becomes unacceptable. As a result, when the roll angle of the vehicle cannot be allowed, a roll restraining moment is applied to the vehicle 1 by the driving force set according to the steering frequency ω, and the roll of the vehicle 1 is restrained.

  When it is determined No in step S103, that is, when the control condition determining unit 31 determines that the actual steering frequency ω is equal to or lower than the steering frequency threshold ω_c, the process returns to START, and the vehicle attitude control device 30 operates the vehicle 1. Monitor status. As described above, when the actual steering frequency ω is equal to or lower than the steering frequency threshold ω_c, it is not necessary to obtain a driving force correction value and a driving force for generating a roll suppression moment, which will be described below. As a result, the calculation load can be reduced, and the load on the vehicle attitude control device 30 can be reduced.

  When the steering operation is performed on the vehicle 1 without comparing the actual steering frequency ω and the steering frequency threshold ω_c, the vehicle 1 is driven with the driving force set according to the steering frequency ω obtained in step S102. A roll restraining moment may be applied to the vehicle 1 by driving the wheel to restrain the roll of the vehicle 1. In this way, although the load on the vehicle attitude control device 30 increases, a roll restraining moment is applied to the vehicle 1 when there is a steering operation, so that the roll of the vehicle 1 increases in a transient state of steering. The phenomenon can be suppressed more reliably.

  When it is determined Yes in step S103, that is, when the control condition determining unit 31 determines that ω> ω_c, the process proceeds to step S104. In step S104, the driving force setting unit 32 generates the driving force (hereinafter referred to as the driving force generated by the driving wheels of the vehicle 1 shown in FIG. 1) that is necessary for setting the roll angle generated in the vehicle 1 to a predetermined target roll angle. Calculate a correction value (referred to as a reference driving force). This correction value is the transient state correction value Kω described above.

  When obtaining the transient state correction value Kω, the driving force setting unit 32 obtains the lateral acceleration Ay of the vehicle 1 from the acceleration sensor 45 shown in FIG. 9, and obtains the steering frequency ω obtained in step S102. The transient state correction value Kω is obtained from the lateral acceleration Ay of the vehicle 1 thus obtained. The steady state correction value Kgy is set in advance. For example, the steady state correction value Kgy can be set so that the roll angle of the vehicle 1 becomes the roll angle when the total mass of the vehicle 1 is the smallest regardless of the total mass of the vehicle 1. When the transient state correction value Kω is obtained, the process proceeds to step S105.

In step S105, the driving force setting unit 32 calculates and obtains a reference driving force. In the present embodiment, the reference driving force is set so as to generate a roll suppression moment M_roll so that the roll angle of the vehicle 1 becomes a preset target roll angle. For example, when the turning of the vehicle 1 shown in FIG. 1 is in a steady state, the target roll angle is the roll angle when the total mass of the vehicle 1 is the smallest. In this way, regardless of the total mass of the vehicle 1, the roll angle of the vehicle 1 becomes the roll angle when the total mass of the vehicle 1 is the smallest. The roll angle of the vehicle 1 in the steady state in consideration of the roll suppression moment M_roll is expressed by Expression (17).
φ = m × ht × Ay / Kφ−M_roll / Kφ (17)

  Therefore, the roll suppression moment M_roll is obtained by substituting the roll angle φ_min when the total mass m of the vehicle 1 is the smallest in the left side of the equation (17), and the driving force that generates the roll suppression moment M_roll is used as the reference driving force. It is given to the drive wheel of the vehicle 1. In this way, when the turning of the vehicle 1 is in a steady state, the roll angle of the vehicle 1 becomes the roll angle when the total mass m of the vehicle 1 is the smallest regardless of the total mass of the vehicle 1.

  Note that the target roll angle is not limited to the roll angle when the total mass of the vehicle 1 is the smallest, and may be set according to vehicle specifications, empirical rules, traveling conditions of the vehicle 1, or the like. Further, considering the case where the steering of the vehicle 1 is in a transient state, the roll suppression moment M_roll and the reference driving force may be set. In this case, ω × j is substituted for the Laplace operator s of the above-described formula (2), and the target roll angle is substituted for the left side of the formula (2). Then, by solving the equation (2) for the roll suppression moment M_roll using the steering frequency ω obtained in step S102, the roll suppression moment M_roll considering the transient state can be obtained.

  Next, an example of a method for obtaining the reference driving force from the roll suppression moment M_roll will be described. For example, as illustrated in FIG. 5A, consider a case where the roll is suppressed when the vehicle 1 is turning right. In this case, for example, a driving reaction force toward the vehicle 1 (vehicle left side driving reaction force) is generated from the driving wheel on the left side of the vehicle 1, and a driving reaction force toward the road surface from the driving wheel on the right side of the vehicle 1 (right side of the vehicle). Drive reaction force) is generated. For example, assuming that the roll restraining moment M_roll is generated evenly on each drive wheel of the vehicle 1 (left front wheel 21, right front wheel 2r, left rear wheel 3l, right rear wheel 3r), the moment generated by each drive wheel Each size is M_roll / 4.

  If the moment due to the left front wheel drive reaction force Ffl1 is Mfl, the moment due to the left rear wheel drive reaction force Frl1 is Mrl, the moment due to the right front wheel drive reaction force Ffr1 is Mfr, and the moment due to the right rear wheel drive reaction force Frr1 is Mrr = Mfl = Mrl = Mfr = Mrr = M_roll / 4. Further, from FIG. 5-1, Mfl = Ffl1 × Df / 2, Mrl = Frl1 × Dr / 2, Mfr = Ffr1 × Df / 2, and Mrr = Frr1 × Dr / 2. Therefore, the driving reaction force of each driving wheel (left front wheel 21, right front wheel 2r, left rear wheel 31, right rear wheel 3r) of the vehicle 1 can be obtained. Then, the reference driving force of each driving wheel of the vehicle 1, that is, the driving force ΔFfl, ΔFfr, ΔFrl, ΔFrr for generating the roll suppression moment M_roll is obtained from the driving reaction force of each driving wheel obtained by the above procedure. Can do.

  Note that when the driving force setting unit 32 calculates the reference driving force of each driving wheel, the total driving of the vehicle 1 before the roll suppression moment M_roll is generated from the viewpoint of suppressing drivability reduction and stabilizing vehicle behavior. It is preferable that the force F_all (= Ffl_b + Ffr_b + Frl_b + Frr_b) and the subsequent total driving force F_all (= Ffl + Ffr + Frl + Frr) of the vehicle 1 be constant. In the above example, as illustrated in FIG. 5A, when the roll restraining moment M_roll is generated by reversing the directions of the driving reaction force on the right side and the driving reaction force on the left side of the vehicle 1, The driving force on the right side increases and the driving force on the left side decreases. As a result, the increase in the driving force on the right side of the vehicle 1 and the decrease in the driving force on the left side are offset, so that the total driving force F_all of the vehicle 1 is substantially constant before and after the roll suppression moment M_roll is generated. Become.

  The reference driving forces ΔFfl, ΔFfr, ΔFrl, ΔFrr obtained in this way are driving forces necessary for generating the roll restraining moment M_roll. The driving forces (hereinafter referred to as actual driving forces) Ffl, Ffr, Frl, Frr (corresponding to the output command values to the inverter 6) actually generated by the driving wheels are the values that the vehicle 1 has traveled until then. This is a value obtained by adding the reference driving forces ΔFfl, ΔFfr, ΔFrl, ΔFrr for generating the roll suppression moment M_roll to the driving forces Ffl_b, Ffr_b, Frl_b, Frr_b of the driving wheels. Accordingly, when the roll restraining moment M_roll is generated, the left front wheel actual driving force Ffl is Ffl_b + ΔFfl, the right front wheel actual driving force Ffr is Ffr_b + ΔFfr, the left rear wheel actual driving force Frl is Frl_b + ΔFrl, and the right rear wheel actual driving force Frr is Frr_b + ΔFrr. . Note that the actual driving force of each driving wheel of the vehicle 1 may be regenerative.

  When the reference driving force is obtained in step S105, the process proceeds to step S106. In step S106, the driving force setting unit 32 corrects the reference driving force obtained in step S105 with the correction value obtained in step S104, that is, the transient state correction value Kω, and obtains the roll suppression driving force. More specifically, by multiplying the reference driving force by the transient state correction value Kω, the reference driving force is corrected and the roll suppression driving force is obtained. Since the transient state correction value Kω is a value larger than 1, the corrected reference driving force, that is, the roll suppression driving force is larger than the value obtained in step S105. Therefore, the roll suppression driving force applied to each driving wheel provided in the vehicle 1, that is, the actual driving force of each driving wheel is larger than before the reference driving force is corrected by the transient state correction value Kω. As a result, when the roll suppression driving force with the reference driving force corrected by the transient state correction value Kω is applied to each drive wheel of the vehicle 1, the vehicle 1 is more than before the reference driving force is corrected by the transient state correction value Kω. A large roll restraining moment occurs. As a result, an increase in the roll direction displacement Y in the vicinity of the resonance steering frequency ωn, that is, an increase in the roll angle in the vicinity of the resonance steering frequency ωn as shown in FIG. 6 can be suppressed.

  If the reference driving force is corrected in step S106, the process proceeds to step S107. In step S107, the driving force control unit 33 included in the vehicle attitude control device 30 drives each driving wheel included in the vehicle 1 with the roll suppression driving force obtained based on the reference driving force corrected in step S106. In the present embodiment, the driving force control unit 33 controls the inverter 6 to drive the left front motor 10l, the right front motor 10r, the left rear motor 11l, and the right rear motor 11r, and each of the vehicles 1 includes Drive the drive wheels.

  Accordingly, when the steering of the vehicle 1 shown in FIG. 1 is in a transient state, the phenomenon that the roll angle of the vehicle 1 increases in the vicinity of the resonance steering frequency ωn can be suppressed, and handling / rollover can be avoided. Next, the second vehicle attitude control according to the present embodiment will be described. In the first vehicle attitude control, the roll suppression driving force is obtained by correcting the reference driving force with the transient state correction value Kω, but the method for obtaining the roll suppression driving force is not limited to this. (The same applies hereinafter). The second vehicle attitude control can be realized by a vehicle attitude control device 30 shown in FIG. In the following description, please refer to FIGS.

(Second vehicle attitude control)
The second vehicle attitude control is common to the first vehicle attitude control in that the roll suppression driving force for generating the roll suppression moment according to the steering frequency is the same as the first vehicle attitude control, but the vehicle roll angle is a predetermined threshold value. The difference is that a driving force for generating a roll restraining moment is applied when the pressure exceeds.

  FIG. 11 is a flowchart showing a procedure of second vehicle attitude control according to the present embodiment. In executing the second vehicle attitude control according to the present embodiment, in step S201, the control condition determination unit 31 determines whether or not a steering operation has been performed on the vehicle 1 shown in FIG. When it determines with No by step S201, ie, when the control condition determination part 31 determines with no steering operation with respect to the vehicle 1, it returns to START and the vehicle attitude | position control apparatus 30 monitors the driving | running state of the vehicle 1. FIG.

  When it determines with Yes at step S201, ie, when the control condition determination part 31 determines with there being steering operation with respect to the vehicle 1, it progresses to step S202. In step S202, the driving force setting unit 32 acquires the steering angle θ of the steering wheel of the vehicle 1 from the steering angle sensor 43 of FIG. 9, and acquires the steering angle θ and the steering angular acceleration θ ′ calculated based on the acquired steering angle θ. Based on the above, the steering frequency ω is obtained. Details of the method for obtaining the steering frequency ω of the vehicle 1 are as described above. When the steering frequency ω of the vehicle 1 is obtained, the process proceeds to step S203.

  In step S203, the driving force setting unit 32 calculates and calculates a reference driving force correction value. Since this correction value is the same as the transient state correction value Kω described in the first vehicle attitude control, the description thereof is omitted. When the transient state correction value Kω is obtained, the process proceeds to step S204. In step S204, the control condition determining unit 31 determines whether or not the roll angle φ of the vehicle 1 shown in FIG. 1 is larger than a predetermined threshold φ_c.

The roll angle threshold value φ_c may be set to a predetermined value in advance based on an empirical rule, the specification of the vehicle 1, or the like, or may be changed according to traveling conditions such as a steering speed and a vehicle speed. The roll angle φ of the vehicle 1 is the roll angle of the vehicle 1 at the time of determination in step S204. As the roll angle, for example, the roll angle in the case where the turning of the vehicle 1 is in a steady state shown in Expression (18) can be used. In this way, since the roll angle can be easily obtained, the calculation load can be reduced.
φ = m × ht × Ay / Kφ (18)

Further, considering that the steering of the vehicle 1 is in a transient state, the roll angle φ of the vehicle 1 obtained using the steering frequency ω obtained in step S202 may be used. When the steering frequency ω is used, the roll angle φ is obtained from Expression (18) arranged by substituting ω × j for s in Expression (6). In this way, a roll angle closer to the actual turning state can be obtained.
φ = m × ht × Ay / √ {(Kφ−I × ω) ² + (Cφ × ω) ² } (19)

  When it is determined No in step S204, that is, when the control condition determination unit 31 determines that φ ≦ φ_c, the process returns to START, and the vehicle attitude control device 30 monitors the driving state of the vehicle 1. If it is determined Yes in step S204, that is, if the control condition determination unit 31 determines that φ> φ_c, it can be determined that an unacceptable roll has occurred in the vehicle 1. In this case, the process proceeds to step S205.

  In step S205, the driving force setting unit 32 calculates and obtains a reference driving force. Since the reference driving force in the second vehicle attitude control is the same as the reference driving force described in the first vehicle attitude control described above, the description thereof is omitted. When the reference driving force is obtained in step S205, the process proceeds to step S206. In step S206, the driving force setting unit 32 corrects the reference driving force obtained in step S205 with the correction value obtained in step S203, that is, the transient state correction value Kω, and obtains the roll suppression driving force. Since this correction is the same as the first vehicle attitude control described above, description thereof is omitted.

  In step S206, when the reference driving force obtained in step S205 is corrected and the roll suppression driving force is set, in step S207, the driving force control unit 33 is set based on the reference driving force corrected in step S206. Each drive wheel with which the vehicle 1 is equipped is driven with the roll suppression driving force. Accordingly, when the steering of the vehicle 1 shown in FIG. 1 is in a transient state, the phenomenon that the roll angle of the vehicle 1 increases in the vicinity of the resonance steering frequency ωn can be suppressed, and handling / rollover can be avoided.

  In the second vehicle attitude control, when the roll angle φ of the vehicle 1 is larger than the roll angle threshold φ_c, the driving wheels of the vehicle 1 are driven with the driving force set according to the steering frequency ω obtained in step S202. Thus, a roll suppression moment is applied to the vehicle 1 to suppress the roll of the vehicle 1. Accordingly, when the roll angle φ of the vehicle 1 is equal to or less than the roll angle threshold φ_c, it is necessary to obtain the driving force correction value, that is, the driving force for generating the transient state correction value Kω and the roll suppression moment M_roll. Disappears. As a result, the calculation load can be reduced, and the load on the vehicle attitude control device 30 can be reduced.

  If the roll angle φ of the vehicle 1 is not compared with the roll angle threshold value φ_c and a steering operation is performed on the vehicle 1, the driving force of the vehicle 1 is set with the driving force set according to the steering frequency ω obtained in step S202. A roll restraining moment may be applied to the vehicle 1 by driving the drive wheels to restrain the roll of the vehicle 1. In this way, although the load on the vehicle attitude control device 30 increases, a roll restraining moment is applied to the vehicle 1 when there is a steering operation, so that the roll of the vehicle 1 increases in a transient state of steering. The phenomenon can be suppressed more reliably. Next, the third vehicle attitude control according to the present embodiment will be described. The third vehicle attitude control can be realized by a vehicle attitude control device 30 shown in FIG. In the following description, please refer to FIGS.

(Third vehicle attitude control)
In the third vehicle attitude control, when the roll angle of the vehicle exceeds a predetermined threshold, a roll suppression driving force for generating a roll suppression moment according to the steering frequency is applied. Although common to attitude control, when the roll angle of the vehicle exceeds a predetermined threshold, a driving force capable of generating a roll suppression moment capable of suppressing the maximum roll assumed in the transient state of steering is applied. Different.

  FIG. 12 is a flowchart showing the procedure of the third vehicle attitude control according to the present embodiment. In executing the third vehicle attitude control according to the present embodiment, in step S301, the control condition determination unit 31 determines whether or not a steering operation has been performed on the vehicle 1 shown in FIG. When it is determined No in step S301, that is, when the control condition determination unit 31 determines that there is no steering operation on the vehicle 1, the process returns to START, and the vehicle attitude control device 30 monitors the driving state of the vehicle 1.

  When it determines with Yes at step S301, ie, when the control condition determination part 31 determines with there being steering operation with respect to the vehicle 1, it progresses to step S302. In step S302, the control condition determination unit 31 determines whether or not the roll angle φ of the vehicle 1 shown in FIG. 1 is larger than a predetermined threshold (hereinafter referred to as roll angle threshold) φ_c. When it is determined No in step S302, that is, when the control condition determination unit 31 determines that φ ≦ φ_c, the process returns to START, and the vehicle attitude control device 30 monitors the driving state of the vehicle 1.

  When it is determined Yes in step S302, that is, when the control condition determination unit 31 determines that φ> φ_c, it can be determined that an unacceptable roll is generated in the vehicle 1. In this case, the process proceeds to step S303. In step S303, the driving force setting unit 32 calculates and obtains a reference driving force. Since the reference driving force in the third vehicle attitude control is the same as the reference driving force described in the first vehicle attitude control described above, the description thereof is omitted.

  When the reference driving force is obtained in step S303, the process proceeds to step S304. In step S304, the driving force setting unit 32 sets the roll suppression driving force by correcting the reference driving force with the maximum correction value. The maximum correction value is a transient state correction value at a steering frequency at which the amplitude with respect to the roll direction of the vehicle 1 is maximum (that is, the steering frequency at which the roll angle of the vehicle 1 is maximum). Since the steering frequency at which the amplitude with respect to the roll direction of the vehicle 1 is maximum is the resonance steering frequency ωn described above, the maximum transient state correction value Kω is the transient state correction value at the resonance steering frequency ωn (hereinafter referred to as a correction value at resonance). Kω_max.

  Since the resonance steering frequency ωn can be obtained from the equation (5), if the lateral acceleration Ay acting on the vehicle 1 is known, the resonance correction value Kω_max can be obtained. The driving force setting unit 32 acquires the lateral acceleration Ay acting on the vehicle 1 from the acceleration sensor 45 shown in FIG. 9, and obtains the resonance correction value Kω_max based on the above-described equations (11) and (12). Then, the reference driving force obtained in step S303 is corrected by the resonance correction value Kω_max. More specifically, the reference driving force is corrected by multiplying the reference driving force by the resonance correction value Kω_max. Since the resonance correction value Kω_max is larger than 1, the corrected reference driving force is larger than the value obtained in step S303. If the roll suppression driving force obtained by correcting the reference driving force with the resonance correction value Kω_max is applied to the driving wheel of the vehicle 1, a roll suppression moment that can suppress the maximum roll assumed in the transient state of the steering is applied to the vehicle. 1 can be given.

  When the reference driving force is corrected, the process proceeds to step S305. In step S305, the driving force control unit 33 drives each driving wheel included in the vehicle 1 with the actual driving force obtained based on the reference driving force corrected in step S304. The resonance correction value Kω_max is a correction value for suppressing the roll at the resonance steering frequency ωn at which the roll angle of the vehicle 1 becomes the largest in the transient state of the steering, so that the same lateral acceleration Ay occurs in the vehicle 1. The roll restraining moment M_roll to be performed is the largest. As a result, when the steering of the vehicle 1 shown in FIG. 1 is in a transient state, the phenomenon that the roll angle of the vehicle 1 increases in the vicinity of the resonance steering frequency ωn is more reliably suppressed, and handling and rollover are more reliably performed. Can be avoided.

  Here, as in the first vehicle attitude control, the steering frequency ω of the vehicle 1 is compared with the steering frequency threshold value ω_c, and based on the result, the roll suppression moment is determined by the driving force set according to the steering frequency ω. May be applied to the vehicle 1 to suppress the roll of the vehicle 1. Further, when step S302 is not executed, that is, when the steering operation is performed on the vehicle 1 without comparing the roll angle φ of the vehicle 1 with the roll angle threshold value φ_c, the driving force set in accordance with the steering frequency ω. The roll of the vehicle 1 may be restrained by applying a roll restraining moment to the vehicle 1 by driving the drive wheels of the vehicle 1. Next, the fourth vehicle attitude control according to the present embodiment will be described. The fourth vehicle attitude control can be realized by a vehicle attitude control device 30 shown in FIG. In the following description, please refer to FIGS.

(Fourth vehicle attitude control)
In the fourth vehicle attitude control, when the roll angle of the vehicle exceeds a predetermined threshold, a roll restraining driving force that generates a roll restraining moment capable of restraining the maximum roll assumed in the transient state of steering is applied. This is the same as the third vehicle attitude control, except that after the steering frequency is determined, a roll suppression driving force set based on the determined steering frequency is applied.

  FIG. 13 is a flowchart showing the procedure of the fourth vehicle attitude control according to the present embodiment. FIG. 14 is a timing chart illustrating the fourth vehicle attitude control according to the present embodiment. Steps S401 and S402 of the fourth vehicle attitude control according to the present embodiment are the same as steps S301 and S302 of the third vehicle attitude control described above, and thus description thereof is omitted.

  When it is determined Yes in step S402, that is, when the control condition determination unit 31 determines that φ> φ_c, it can be determined that an unacceptable roll has occurred in the vehicle 1. In this case, the process proceeds to step S403. In step S403, the driving force setting unit 32 calculates and obtains the reference driving force, obtains the steering angle θ from the steering angle sensor 43, and starts computation for obtaining the steering frequency ω. Since the reference driving force in the fourth vehicle posture control is the same as the reference driving force described in the first vehicle posture control described above, the description thereof is omitted.

  When the reference driving force is obtained in step S403 and calculation for obtaining the steering frequency ω is started, the process proceeds to step S404. In step S404, the driving force setting unit 32 sets the roll suppression driving force by correcting the reference driving force with the above-described maximum correction value, that is, the resonance correction value Kω_max. More specifically, the reference driving force is corrected by multiplying the reference driving force obtained in step S403 by the resonance correction value Kω_max to set the roll suppression driving force. If the roll suppression driving force set in this way is applied to the drive wheels of the vehicle 1, a roll suppression moment that can suppress the maximum roll assumed in the transient state of steering can be applied to the vehicle 1.

  When the reference driving force is corrected, the process proceeds to step S405. In step S405, the provided driving force control unit 33 drives each driving wheel provided in the vehicle 1 with the roll suppression driving force obtained based on the reference driving force corrected in step S404. In the timing chart shown in FIG. 14, from t = t0, each drive wheel provided in the vehicle 1 is driven with a roll suppression driving force that is set by correcting the reference driving force with the resonance correction value Kω_max.

  Next, in step S406, the control condition determination unit 31 determines whether or not the steering frequency ω has been determined. As described above, in order to ensure the accuracy of the steering frequency ω, some information on the steering angle θ is required. In the timing chart shown in FIG. 14, the time for acquiring the amount of information of the steering angle θ necessary for ensuring the accuracy of the steering frequency ω is t1. In the fourth vehicle attitude control, until the accuracy of the steering frequency ω can be ensured, each driving wheel included in the vehicle 1 is driven with the roll suppression driving force set by correcting the reference driving force with the correction value Kω_max during resonance. To do. After the accuracy of the steering frequency ω is ensured, the steering frequency ω is determined as the steering frequency used for the fourth vehicle attitude control, and the reference driving force is corrected based on the determined steering frequency ω. Thus, the roll suppression driving force is set.

  The roll suppression driving force set by correcting the reference driving force with the resonance correction value Kω_max is for suppressing the roll of the vehicle 1 at the resonance steering frequency ωn, and is the maximum roll assumed in the transient state of steering. A roll restraining moment capable of restraining is generated. Therefore, when the steering frequency ω is not the resonance steering frequency ωn, the driving wheels of the vehicle 1 are driven with an excessive driving force, which may increase the consumption of driving energy. In the fourth vehicle attitude control, after the steering frequency ω is determined, the roll suppression driving force is set based on the determined steering frequency ω. Therefore, the time during which the driving wheels of the vehicle 1 are driven with an excessive driving force is set. Can be shortened. As a result, an increase in energy consumption can be suppressed.

  In step S406, for example, when a predetermined time t1 for acquiring the amount of information of the steering angle θ necessary for ensuring the accuracy of the steering frequency ω has passed, it is determined that the steering frequency ω has been determined. be able to. The predetermined time t1 can be determined in advance by analysis. In addition, for example, when the rate of change of the steering frequency ω (see FIG. 14) obtained based on the acquired steering angle θ is smaller than a predetermined threshold, it may be determined that the steering frequency ω is fixed. it can. In any case, since a predetermined time is required until the steering frequency ω is determined after the acquisition of the steering angle θ is started, the reference driving force is set to the resonance correction value until the predetermined time elapses. Each drive wheel with which the vehicle 1 is equipped is driven with the roll suppression driving force set by correcting with Kω_max.

  When it is determined No in step S406, that is, when the control condition determining unit 31 determines that the steering frequency ω is not fixed, the roll suppression driving force obtained by correcting the reference driving force with the resonance correction value Kω_max. Then, each drive wheel provided in the vehicle 1 is driven. If it is determined Yes in step S406, that is, if the control condition determination unit 31 determines that the steering frequency ω has been determined, the process proceeds to step S407.

  In step S407, the driving force setting unit 32 calculates a reference driving force correction value, that is, a transient state correction value Kω, using the determined steering frequency ω. In step S408, the driving force setting unit 32 corrects the reference driving force with the reference driving force correction value obtained in step S407, that is, the transient state correction value Kω. The transient correction value Kω obtained using the determined steering frequency ω is smaller than the resonance correction value Kω_max. Therefore, the roll suppression driving force in which the reference driving force is corrected by the transient state correction value Kω obtained from the determined steering frequency ω is smaller than the roll suppression driving force in which the reference driving force is corrected by the resonance correction value Kω_max.

  In step S409, the driving force control unit 33 drives each driving wheel included in the vehicle 1 with the roll suppression driving force obtained based on the reference driving force corrected in step S408. Accordingly, when the steering of the vehicle 1 shown in FIG. 1 is in a transient state, the phenomenon that the roll angle of the vehicle 1 increases in the vicinity of the resonance steering frequency ωn can be suppressed, and handling / rollover can be avoided. In addition, since it is possible to shorten the time for driving each driving wheel provided in the vehicle 1 with the roll suppression driving force obtained by correcting the reference driving force with the resonance correction value Kω_max, it is possible to suppress an increase in driving energy consumption.

  Here, if it is determined in step S401 that the steering operation has been performed on the vehicle 1, calculation for obtaining the steering frequency ω may be started before comparing the roll angle φ of the vehicle 1 with the roll angle threshold φ_c. Good. In this way, since the steering frequency ω can be determined earlier, the time for outputting the roll suppression driving force corrected by the resonance correction value Kω_max can be shortened.

  Note that, as in the first vehicle attitude control, the steering frequency ω of the vehicle 1 is compared with the steering frequency threshold value ω_c, and based on the result, the roll suppression moment is set by the driving force set according to the steering frequency ω. It may be given to the vehicle 1 to suppress the roll of the vehicle 1. If the steering operation is performed on the vehicle 1 without executing step S402, that is, without comparing the roll angle φ of the vehicle 1 and the roll angle threshold value φ_c, the driving force set according to the steering frequency ω is set. The roll of the vehicle 1 may be restrained by applying a roll restraining moment to the vehicle 1 by driving the drive wheels of the vehicle 1.

  As described above, in the present embodiment, the roll suppression driving force for suppressing the roll of the vehicle is set according to the steering frequency when the steering wheel of the vehicle is steered, and the drive wheel of the vehicle is driven with the set roll suppression driving force. To do. As a result, when the steering is in a transient state, a larger roll restraining moment can be generated than when the steering is in a steady state, so that the phenomenon that the roll of the vehicle increases in the vicinity of the resonant steering frequency can be suppressed. .

  Further, in the present embodiment, when the steering is fast and the steering speed is high, the roll of the vehicle that increases in the vicinity of the resonance steering frequency can be suppressed, so that when fast steering is performed such as during emergency avoidance, There is also an advantage that both the rolling resistance and turning performance of the vehicle can be achieved with certainty. In addition, what is provided with the structure disclosed by this embodiment has an effect | action and effect similar to this embodiment.

  As described above, the vehicle attitude control device and the traveling device according to the present invention are useful for suppressing the roll of the vehicle, and particularly for suppressing the increase of the roll of the vehicle when the steering is in a transient state. Is suitable.

It is the schematic which shows the structure of a vehicle provided with the traveling apparatus which concerns on this embodiment. It is explanatory drawing which shows the structural example of the suspension apparatus for front wheels with which the traveling apparatus which concerns on this embodiment is provided. It is explanatory drawing which shows the structural example of the suspension apparatus for rear wheels with which the traveling apparatus which concerns on this embodiment is provided. It is explanatory drawing which shows the structural example of the suspension apparatus for rear wheels with which the traveling apparatus which concerns on this embodiment is provided. It is explanatory drawing which shows the modification of the traveling apparatus which concerns on this embodiment. It is explanatory drawing which shows the modification of the traveling apparatus which concerns on this embodiment. It is explanatory drawing which shows the modification of the traveling apparatus which concerns on this embodiment. It is explanatory drawing which shows the modification of the traveling apparatus which concerns on this embodiment. It is a conceptual diagram for demonstrating the vehicle attitude | position control which concerns on this embodiment. It is a conceptual diagram for demonstrating the vehicle attitude | position control which concerns on this embodiment. It is a conceptual diagram explaining a driving reaction force. It is a conceptual diagram which shows the relationship between a steering frequency and the amplitude of the roll direction of a vehicle. It is explanatory drawing which shows the relationship between a roll direction displacement and a steering frequency. It is explanatory drawing which shows the time change of a steering angle and a steering frequency, and the time change of a transient state correction value. It is explanatory drawing which shows the structural example of the vehicle attitude | position control apparatus which concerns on this embodiment. It is a flowchart which shows the procedure of the 1st vehicle attitude | position control which concerns on this embodiment. It is a flowchart which shows the procedure of the 2nd vehicle attitude | position control which concerns on this embodiment. It is a flowchart which shows the procedure of the 3rd vehicle attitude | position control which concerns on this embodiment. It is a flowchart which shows the procedure of the 4th vehicle attitude | position control which concerns on this embodiment. It is a timing chart explaining the 4th vehicle posture control concerning this embodiment.

Explanation of symbols

1, 1a, 1b, 1c, 1d Vehicle 2l Left front wheel 2r Right front wheel 3l Left rear wheel 3r Right rear wheel 4 Handle 6 Inverter 8 Suspension device for front wheel 9 Suspension device for rear wheel 10l Left front motor 10r Right front motor 11l Left rear Side motor 11r Right rear motor 30 Vehicle attitude control device 31 Control condition determination unit 32 Driving force setting unit 33 Driving force control unit 43 Steering angle sensor 45 Acceleration sensor 46f Front wheel stroke sensor 46r Rear wheel stroke sensor 50 ECU
60 Driving device 100, 100a, 100b, 100c, 100d Traveling device

Claims (14)

In a vehicle attitude control device that controls a traveling device of a vehicle capable of varying the driving force of the driving wheel between at least a pair of left and right driving wheels,
In order to generate a roll suppression moment that suppresses the roll of the vehicle, a roll suppression driving force generated on at least one of the left and right drive wheels is determined according to a steering frequency when the steering wheel of the vehicle is steered. A driving force setting unit to be set;
A driving force control unit that applies a driving force to the driving wheel based on the driving force set by the driving force setting unit;
A vehicle attitude control device comprising: The driving force setting unit includes:
2. The vehicle attitude according to claim 1, wherein the roll suppression driving force is set using a resonance steering frequency obtained from an inertia in a roll direction of the vehicle and a roll rigidity of the vehicle as the steering frequency. Control device. The driving force setting unit includes:
Until the predetermined time elapses in advance, using the resonance steering frequency, the roll suppression driving force is obtained,
After the predetermined time has elapsed, the roll suppression driving force is obtained using a steering frequency obtained based on a ratio between an actual steering angle and an acceleration of the steering angle obtained from the actual steering angle. The vehicle attitude control device according to claim 2. The driving force setting unit includes:
4. The steering frequency according to claim 1, wherein the steering frequency is obtained based on a ratio between an acceleration of a steering angle obtained from an actual steering angle of the vehicle and an actual steering angle of the vehicle. The vehicle attitude control device according to claim 1. The driving force setting unit includes:
The roll suppression driving force is obtained by obtaining a reference driving force necessary for setting the roll angle of the vehicle to a predetermined target roll angle and correcting the reference driving force based on a correction value corresponding to the steering frequency. The vehicle attitude control device according to any one of claims 1 to 4, wherein the vehicle attitude control device is set. Roll angle detection means for detecting the roll angle of the vehicle,
The said driving force control part provides the said roll suppression driving force, when the roll angle detection means detects the roll angle of the said vehicle exceeding the predetermined threshold value. The vehicle attitude control device according to any one of the above. The roll angle is
The vehicle attitude according to claim 6, wherein the vehicle attitude is determined based on a total mass of the vehicle, a height of a center of gravity of the vehicle determined based on a total mass of the vehicle, and a lateral acceleration acting on the vehicle. Control device. In a vehicle travel device capable of differentiating the driving force of the drive wheels between at least a pair of left and right drive wheels,
A roll suppression driving force that generates a roll suppression moment that suppresses the roll of the vehicle is set according to a steering frequency when the steering wheel of the vehicle is steered, and the left and right of the left and right are set by the set roll suppression driving force. A traveling device that drives drive wheels.   9. The travel device according to claim 8, wherein the roll suppression driving force is set using a resonance steering frequency obtained from inertia in the roll direction of the vehicle and roll rigidity of the vehicle as the steering frequency. Until the predetermined time elapses, the roll steering driving force is set using the resonance steering frequency,
After the predetermined time has elapsed, the roll suppression driving force is calculated using the steering frequency obtained based on the ratio of the actual steering angle of the vehicle and the acceleration of the steering angle obtained from the actual steering angle. The travel device according to claim 9, wherein the travel device is obtained.   11. The steering frequency according to claim 8, wherein the steering frequency is obtained based on a ratio between an acceleration of a steering angle obtained from an actual steering angle of the vehicle and an actual steering angle of the vehicle. The traveling device according to Item 1.   The roll suppression driving force is set by correcting a reference driving force necessary for setting a roll angle of the vehicle to a predetermined target roll angle based on a correction value corresponding to the steering frequency. The travel device according to any one of claims 8 to 11.   Roll angle detection means for detecting the roll angle of the vehicle is provided, and the roll suppression driving force is applied when the roll angle detection means detects the roll angle of the vehicle exceeding a predetermined threshold. The travel device according to any one of claims 8 to 12.   The roll angle is obtained based on the total mass of the vehicle, the height of the center of gravity of the vehicle obtained based on the total mass of the vehicle, and the lateral acceleration acting on the vehicle. The traveling device described.

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