JP2016183581A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the ability to escape from a stack state. A brake ECU sets a direction in which the vehicle body is swung when acceleration slip is detected in some drive wheels, and the vehicle body resonates in the pitch direction when the vehicle body is swung in the pitch direction. When calculating the driving force waveform that increases or decreases the driving force at the natural frequency and swings the vehicle body in the roll direction, the driving force waveform that increases or decreases the driving force at the natural frequency at which the vehicle body resonates in the roll direction And an excitation command representing the calculated driving force waveform is transmitted to the engine ECU. As a result, the vehicle body swings in the pitch direction or the roll direction, and the wheel floating from the ground is temporarily grounded, and the driving force is transmitted to the ground when the wheel is grounded. [Selection] Figure 2

Description

  The present invention relates to a vehicle control device that controls a driving force to cause a vehicle to escape from a stacked state.

  Conventionally, various techniques for escaping a vehicle from a stacked state are known. For example, in the device of Patent Document 1, it is determined that the vehicle is stuck when the wheel speed difference between the left and right drive wheels exceeds a predetermined value, and the brake pressure is increased rapidly. As a result, the drive wheel vibrates due to a sudden decrease in the rotational speed or an impact caused by the lock. In the apparatus of Patent Document 1, escape from the stack state is attempted by such vibration of the drive wheels.

JP 2010-149697 A

  However, even if the driving wheel is vibrated by an impact caused by the brake pressure, it cannot be said that it is very effective for escape from the stacked state. For example, when the vehicle stops due to a large unevenness formed on the ground and one of the driving wheels floats off the ground, it is difficult to escape from the stacked state.

  The present invention has been made to solve the above-described problems, and an object thereof is to improve the ability to escape from a stack state.

In order to achieve the above object, the features of the present invention are:
In a vehicle control apparatus for controlling a driving force generated by a driving source (11) for driving a plurality of driving wheels,
Slip detecting means (30, 55, S11) for detecting a state in which some of the plurality of driving wheels are accelerating slip;
The driving force generated by the driving source at the natural frequency at which the vehicle body resonates in the roll direction or the pitch direction when the slip detecting means detects a state where a part of the driving wheel is accelerated and slipped. And vibration control means (10, 30, S15, S21, S23) for increasing or decreasing the frequency.

  In the present invention, when the slip detection means detects a state in which a part of the plurality of driving wheels is accelerated slipping (idling), the vibration control means causes the natural vibration in which the vehicle body resonates in the roll direction or the pitch direction. The driving force generated by the driving source is increased or decreased by the number. Thereby, a force in the front-rear direction can be applied to the vehicle body by increasing or decreasing the driving force of the driving wheels that have not accelerated slip. In this case, if the driving force is increased or decreased at the natural frequency that resonates in the roll direction (the natural frequency that excites the movement in the roll direction), the vehicle body resonates with the input from the drive wheels and greatly fluctuates in the roll direction. Move. In addition, when the driving force is increased or decreased at the natural frequency that resonates in the pitch direction (the natural frequency that excites motion in the pitch direction), the vehicle body resonates with the input from the drive wheels and swings greatly in the pitch direction. To do.

  Thus, for example, even when one of the drive wheels floats off the ground and cannot travel, the vehicle body is swung in the roll direction or the pitch direction by increasing or decreasing the drive force of the grounded drive wheel. Can be moved. Due to the swinging of the vehicle body, the driving wheel floating from the ground (the driving wheel that is accelerating and slipping) is repeatedly grounded according to the swinging of the vehicle body, and the driving force is applied to the ground while it is in contact with the ground. Can be transmitted. Thereby, the escape capability from a stack state can be improved.

  In the above description, in order to help the understanding of the invention, the reference numerals used in the embodiments are attached to the configuration of the invention corresponding to the embodiments in parentheses, but each constituent element of the invention is represented by the reference numerals. It is not limited to the embodiments specified.

It is a schematic block diagram of the control apparatus of the vehicle which concerns on this embodiment. It is a flowchart showing a vehicle body vibration control routine. It is a figure showing the state where one of the driving wheels is floating from the ground. It is a graph showing a driving force waveform.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic system configuration diagram of a vehicle including the vehicle control device of the present embodiment.

  The vehicle includes an engine 11, an automatic transmission 12, a transfer 13, and an engine ECU 10. The driving force of the engine 11 is transmitted to the output shaft 14 via the automatic transmission 12. The driving force of the output shaft 14 is transmitted to the front wheel driving shaft 15 and the rear wheel driving shaft 16 by the transfer 13 that switches the driving state. The engine 11, the automatic transmission 12, and the transfer 13 are controlled by the engine ECU 10.

  The engine ECU 10 is an electronic control device including a microcomputer as a main part, and receives detection signals E output from various engine control sensors 51 to perform fuel injection control, ignition control, and intake air amount. Implement control. The engine ECU 10 is connected to an accelerator sensor 52 that detects an accelerator operation amount A (accelerator opening), calculates a driver request torque having a magnitude corresponding to the accelerator operation amount A, and sends the driver request torque to the engine 11. To generate.

  The transfer 13 includes an actuator that switches the driving state between a 4WD state and a 2WD state, and the driving state is switched by the engine ECU 10. The engine ECU 10 is connected to the transfer selection switch 53, and switches the driving state (driving force transmission state) of the transfer 13 based on the transfer selection signal St output from the transfer selection switch 53 operated by the driver.

  For example, when the transfer selection switch 53 is set at the H4 position, the transfer 13 is set to the high speed 4WD mode that transmits the driving force of the output shaft 14 to the front wheel driving shaft 15 and the rear wheel driving shaft 16. Further, when the transfer selection switch 53 is set at the H2 position, the transfer 13 is set to a high speed 2WD mode in which the driving force of the output shaft 14 is transmitted only to the rear wheel driving shaft 16. Further, when the transfer selection switch 53 is set at the L4 position, the transfer 13 causes the driving force for the low vehicle speed and high torque to be output from the output shaft 14 as compared with the case of the H4 position. Is transmitted to the front wheel drive shaft 15 and the rear wheel drive shaft 16 in the low speed 4WD mode.

  The driving force of the front wheel drive shaft 15 is transmitted to the left front wheel axle 17L and the right front wheel axle 17R via the front wheel differential gear 17. As a result, the left front wheel 20FL and the right front wheel 20FR are rotationally driven. Similarly, the driving force of the rear wheel drive shaft 16 is transmitted to the left rear wheel axle 18L and the right rear wheel axle 18R via the rear wheel differential gear 18. Thereby, the left rear wheel 20RL and the right rear wheel 20RR are rotationally driven.

  Hereinafter, when it is not necessary to specify the positions of the left front wheel 20FL, the right front wheel 20FR, the left rear wheel 20RL, and the right rear wheel 20RR, they are simply referred to as wheels 20. In addition, regarding members provided for each wheel 20 position described below, in the drawing, FL is assigned to the member provided corresponding to the left front wheel 20FL at the end of the reference numeral, and corresponds to the right front wheel 20FR. In the specification, FR is attached to members provided for the left rear wheel 20FL, RL is attached to members provided for the left rear wheel 20FL, and RR is attached to members provided for the right rear wheel 20RR. In the case where the wheel position does not need to be specified, the last symbol is omitted.

  The engine 11 is elastically supported on the vehicle body by a variable engine mount 19. The variable engine mount 19 is configured to suppress vibrations transmitted from the engine 11 to the vehicle body and to adjust the damping characteristics (for example, damping characteristics). The vibration damping characteristic of the variable engine mount 19 is adjusted by the engine ECU 10. When cylinder deactivation control is performed to stop combustion by closing the supply / exhaust valves of some cylinders for the purpose of improving the fuel consumption of the engine 11, vibration noise is caused. In general, the variable engine mount 19 is provided so as to reduce vibration noise by switching the vibration damping characteristics when performing such cylinder deactivation control. Also used at runtime.

  The engine ECU 10 is connected to other in-vehicle ECUs such as a brake ECU 30 and an absorber ECU 40, which will be described later, via a CAN communication line 70 so that control information and request signals for the engine 11 and the like are transmitted to the other in-vehicle ECUs. While transmitting, the control information and request signal are received from other in-vehicle ECUs.

  The vehicle includes a friction brake mechanism 31, a brake actuator 32, and a brake ECU 30 provided on the left and right front and rear wheels. The friction brake mechanism 31 includes a brake disc 31a fixed to the wheel 20 and a brake caliper 31b fixed to the vehicle body. The wheel built in the brake caliper 31b by the hydraulic pressure of the hydraulic fluid supplied from the brake actuator 32. By operating the cylinder, the brake pad is pressed against the brake disc 31a to generate a friction braking force.

  The brake actuator 32 is a known actuator that independently adjusts the hydraulic pressure supplied to the wheel cylinder built in the brake caliper 31b. The brake actuator 32 has, for example, a control hydraulic pressure that can be controlled independently of the brake pedal depression force, in addition to a pedal effort hydraulic circuit that supplies hydraulic pressure to the wheel cylinder from a master cylinder that pressurizes hydraulic fluid by the depression force of the brake pedal. A control hydraulic circuit is provided to supply each wheel cylinder independently. The control hydraulic circuit has a booster pump and an accumulator to generate a high hydraulic pressure, and adjusts the hydraulic pressure output from the hydraulic power generator to achieve the target hydraulic pressure for each wheel cylinder. A control valve for supplying a controlled hydraulic pressure, a hydraulic pressure sensor for detecting the hydraulic pressure of each wheel cylinder, and the like are provided (the elements constituting the brake actuator 32 are not shown).

  By providing such a configuration, the brake actuator 32 can independently control the braking force of the left and right front and rear wheels 20.

  The brake ECU 30 is an electronic control device including a microcomputer as a main part, and is connected to the brake actuator 32 to control the operation of the brake actuator 32. The brake ECU 30 is connected to another in-vehicle ECU such as the engine ECU 10 via a CAN communication line 70 so as to be able to communicate with each other. The brake ECU 30 inputs a detection signal output from the brake sensor 54 that detects the brake operation amount B, calculates a driver-requested braking force according to the brake operation amount B, and further calculates the driver-requested braking force for each wheel 20. The required friction braking force for each wheel distributed to the vehicle is calculated. Then, by controlling the energization of a control valve provided in the brake actuator 32, the hydraulic pressure of each wheel cylinder is controlled so that each friction brake mechanism 31 generates each wheel required friction braking force. Thereby, the braking force of the left and right front and rear wheels 20 is controlled independently.

  In addition, a wheel speed sensor 55 that detects the wheel speed of each wheel 20 is connected to the brake ECU 30. The wheel speed sensor 55 outputs a detection signal representing the rotational speed ω (referred to as the wheel speed ω) of the wheel 20 on which the wheel speed sensor 55 is provided. The brake ECU 30 calculates a vehicle speed V (body speed) based on the wheel speed ω detected by each wheel speed sensor 55 and provides vehicle speed information to the in-vehicle ECU via the CAN communication line 70. And the wheel speed ω of each wheel 20, the slip rate of each wheel 20 is calculated, and the locked state and slip state (idling state) of each wheel 20 are detected based on this slip rate.

  When the brake ECU 30 detects a locked state during braking of the wheel 20, the brake ECU 30 weakens the braking force by a well-known antilock control (ABS) using the wheel 20 in which the locked state is detected as a control target wheel. Further, when the brake ECU 30 detects an acceleration slip (i.e., idling of the driving wheel) when the wheel 20 is driven, the brake ECU 30 applies a braking force by a well-known traction control (TRC) using the wheel 20 in which the acceleration slip is detected as a control target wheel. To do. In addition, as will be described later, the brake ECU 30 performs vehicle body vibration control described later when an acceleration slip of a specific wheel is detected during the off-road control.

  The CAN communication line 70 includes a behavior sensor 56 that detects the behavior of the vehicle (for example, a lateral acceleration sensor that detects the lateral acceleration of the vehicle, a yaw rate sensor that detects the yaw rate of the vehicle), and a steering angle that detects the steering angle. A sensor 57 is connected. As a result, the vehicle behavior amount G detected by the behavior sensor 56 and the information representing the steering angle θ detected by the steering angle sensor 57 are transmitted to the CAN communication line 70 at a predetermined short period.

  The brake ECU 30 acquires vehicle behavior information and steering information via the CAN communication line 70, and on the basis of the information, an undesired motion state due to a side slip such as an oversteer state or an understeer state of the vehicle. Is detected. When the brake ECU 30 detects such an undesired motion state, the brake ECU 30 specifies a wheel to be controlled to control the braking force so as to stabilize the behavior of the vehicle, and controls the braking force of the wheel to be controlled.

  The left and right front and rear wheels 20 are suspended from the vehicle body independently by suspensions (not shown). Each suspension is provided with a shock absorber 41 of a variable damping force type. The shock absorber 41 has its damping force (damping coefficient) controlled by the absorber ECU 40.

  The absorber ECU 40 is an electronic control unit including a microcomputer as a main part, and is connected to a suspension sensor 42 that detects a vibration state (spring-on vibration, un-spring vibration, etc.) at each wheel position, and is detected by the suspension sensor 42. The suspension detection signal Ss thus received is input. As the suspension sensor 42, for example, a sprung acceleration sensor that detects vertical acceleration of the vehicle body, a height sensor that detects suspension stroke, or the like can be used. Based on the suspension detection signal Ss output from the suspension sensor 42, the absorber ECU 40 controls the damping force of each shock absorber 41 so that the vertical vibration of the vehicle body is appropriate.

  Further, the absorber ECU 40 is connected to other in-vehicle ECUs such as the engine ECU 10 and the brake ECU 30 through the CAN communication line 70 so as to be able to communicate with each other, and the damping force of the shock absorber 41 is controlled by a command from the in-vehicle ECU. It is configured to be able to.

  In addition, the vehicle is provided with an off-road selection switch 58, a swing switch 59, and a crawl control switch 60 in the vicinity of the driver's seat for selecting a function suitable for off-road driving. The off-road selection switch 58 is a switch that is selectively operated by the driver when it is desired to receive driving assistance suitable for off-road driving. , A mogul road, a debris road, a muddy road, etc.) and an off-road selection signal So.

  The swing switch 59 is a switch for the driver to select the swing direction of the vehicle body when the vehicle body vibration control described later is being performed, and outputs a swing direction selection signal Sd. Further, the swing switch 59 is not only for selecting the swing direction of the vehicle body, but when operated by the driver, it is presumed that the driver is trying to escape from the stack state when the operation is performed. Thus, it is used as one of triggers for starting the swinging of the vehicle body. The crawl control switch 60 is a switch that selects whether or not to perform effective crawl control in off-road, and outputs a crawl selection signal Sc.

  The off-road selection signal So, the swing direction selection signal Sd, and the crawl selection signal Sc are output to the brake ECU 30. When the off-road selection signal So is in an ON state (a state in which off-road driving support is selected), the brake ECU 30 performs off-road control corresponding to the off-road type in cooperation with the engine ECU 10. During offload control, the control mode of traction control (TRC) is changed. The traction control during this offload control is called active TRC, and the other normal traction control is called normal TRC. In the normal TRC, when the acceleration slip of the drive wheel 20 is detected, the driving force of the engine 11 is reduced and the braking force is applied to the slip wheel. In the active TRC, the slip wheel is set so as not to reduce the driving force of the engine 11. Apply braking force to The brake ECU 30 controls the brake pressure according to the type of off-road, thereby appropriately distributing the driving force of the engine 11 to the drive wheels 20 to support off-road running.

  The brake ECU 30 performs crawl control in cooperation with the engine ECU 10 when the crawl selection signal Sc is in an ON state (a state in which crawl control is selected). This crawl control does not require the driver's accelerator operation and brake operation, and controls the vehicle to run at a constant low vehicle speed (for example, 1 km / h to 5 km / h) while minimizing wheel slip and wheel lock. is there. Accordingly, it is possible to receive off-road driving assistance also by crawl control.

  Such off-road driving support improves the off-road driving performance of rocky terrain, mogul road, rubble road, muddy road, and steep road. However, the ability to drive off-roads still depends on the driving skills of the driver, and it is not always possible to run with such off-road driving support.

  For example, if large irregularities are formed on the ground, the drive wheels 20 may float from the ground, making it impossible to travel on the way. Such a state in which the vehicle cannot travel is called a stuck state. However, at least one of the plurality of drive wheels 20 should be grounded. In the example of FIG. 3, the left rear wheel 20RL is floating from the ground, but the right rear wheel 20RR is in contact with the ground. In this case, if the floating driving wheel 20RL may be temporary, if it is grounded, the driving force of the driving wheel 20RL can be transmitted to the ground while it is grounded, and it is easy to escape from the stacked state.

  Therefore, in the vehicle of the present embodiment, vehicle body vibration control is performed in order to further improve off-road running performance. In this vehicle body vibration control, the wheel 20 that is floating from the ground (having a small grounding load even if not floating) is temporarily grounded (the grounding load is increased) by swinging the vehicle body. In the vehicle body vibration control, the driving force of the driving wheel 20 is vibrated (increased or decreased) with a predetermined amplitude and frequency in order to swing the vehicle body.

  When the driving force of the wheel 20 on the ground side vibrates, a force in the front-rear direction can be applied to the vehicle body, and the vehicle body can be swung. When vibration in the front-rear direction is input from the wheel 20, the vehicle body excites movement in the pitch direction (increases the amplitude of movement in the pitch direction) or excites movement in the roll direction (roll). The amplitude of motion in the direction is increased). That is, when the driving force of the wheel 20 is increased or decreased at the natural frequency at which the motion in the pitch direction is excited, the vehicle body resonates with the input from the wheel 20 and swings greatly in the pitch direction. Further, when the driving force of the wheel 20 is increased or decreased at the natural frequency at which the motion in the roll direction is excited, the vehicle body resonates with the input from the wheel 20 and swings greatly in the roll direction. Note that the movement in the pitch direction means movement around the left-right axis (pitch axis) passing through the center of gravity of the vehicle, and the roll direction means movement around the front-rear direction axis (roll axis) passing through the center of gravity of the vehicle. To do.

  Accordingly, the vehicle body is greatly swung by vibrating the driving force of the wheel 20 at a specific cycle, and the wheel 20 floating from the ground is repeatedly grounded in accordance with the rocking of the vehicle body, and the ground is being grounded. The driving force of the wheel 20 can be transmitted to the ground.

  Further, in the vehicle body excitation control, the damping force of the shock absorber 41 is set on the floating wheel 20 and the wheel 20 provided at the diagonal position of the wheel 20 so as not to attenuate the swing of the vehicle body as much as possible. It is made smaller (the attenuation coefficient is made smaller). Thereby, the fluctuation amplitude of the pitch angle of the vehicle body or the fluctuation amplitude of the roll angle can be increased.

  Further, when the vehicle body swings in the roll direction, the engine 11 (including the automatic transmission 12 and the transfer 13) resonates in the roll direction with an opposite phase to the vehicle body due to the action and reaction. As the amplitude of the engine 11 increases, the roll angle amplitude of the vehicle body also increases. Therefore, in the vehicle body vibration control, the setting of the damping force of the variable engine mount 19 that mounts the engine 11 on the vehicle body is reduced (the damping coefficient is reduced). As a result, the engine 11 swings in the roll direction in the opposite phase with respect to the vehicle body, and the movement of the vehicle body in the roll direction can be promoted by the inertia.

  In vehicle body vibration control, the off-road running performance is improved by swinging the vehicle body in this way. The vehicle body vibration control is performed by cooperative control of the brake ECU 30, the engine ECU 10, and the absorber ECU 40.

  FIG. 2 shows a vehicle body vibration control routine executed by the brake ECU 30. The vehicle body vibration control routine is repeatedly executed at a predetermined short calculation cycle while the ignition switch is on.

  When the vehicle body vibration control routine is started, the brake ECU 30 detects the acceleration slip state of the drive wheels 20 in step S11. For example, the slip ratio is calculated based on the wheel speed ω detected by the wheel speed sensor 55 and the vehicle speed V. Subsequently, in step S12, the brake ECU 30 determines whether or not the during-vibration flag F is “0”. The during-vibration flag F is set to “1” when the driving force of the engine 11 is vibrated (periodically increased or decreased) and the vehicle body is swung as described later, and “0” otherwise. Set to At the time of starting this routine, since the exciting flag F is set to “0”, the brake ECU 30 advances the process to step S13.

  In step S13, the brake ECU 30 determines whether or not an acceleration slip has occurred. If the acceleration slip has not occurred, the brake ECU 30 once ends this routine. The brake ECU 30 repeats such processing. When it is determined in step S13 that an acceleration slip has occurred, the brake ECU 30 determines the driving force of the engine 11 when it is determined in step S14 that the acceleration slip has occurred. Then, it is read from the engine ECU 30 and stored in a nonvolatile memory. In this case, the brake ECU 30 stores the driving force in association with the slip ratio. This driving force is sampled for a certain period of time or a predetermined number of times when the most recent acceleration slip is detected. By using this sampling data, the relationship between the acceleration slip and the driving force, for example, the driving force at which the tire cannot grip the road surface and the acceleration slip begins to occur (having a value corresponding to the friction coefficient μ of the road surface) can be estimated. it can.

  Subsequently, in step S15, the brake ECU 30 determines whether or not the acceleration slip is generated in the specific drive wheel 20, that is, only a part of the drive wheel 20 is in the acceleration slip. Determine whether or not. If all of the drive wheels 20 are accelerating and slipping (S15: No), the exciting flag F is set to “0” in step S16, and this routine is once ended. The determination of whether or not acceleration slip has occurred may be made, for example, by determining whether or not the slip ratio is greater than or equal to a set value.

  On the other hand, if only some of the drive wheels 20 are accelerating and slipping (S15: Yes), the brake ECU 30 is in off-road support control (off-road control, crawl control) in step S17. Alternatively, it is determined whether or not the swing switch 59 has been operated. The off-road support control is started at the driver's will, and the swing switch 59 is operated when the driver tries to escape from the stack state. Accordingly, this step S17 is a process of determining whether or not the driver is aware of receiving off-road support, or whether or not the driver is trying to escape from the stack state. .

  If the brake ECU 30 determines “No” in step S <b> 17, the brake ECU 30 advances the process to step S <b> 16 and then ends this routine once. On the other hand, if “Yes” is determined in step S17, the process from step S18 will be performed in order to assist the driving operation of the driver.

  First, the brake ECU 30 sets the in-vibration flag F to “1” in step S18. Subsequently, the brake ECU 30 determines the swinging direction of the vehicle body in step S19. In this embodiment, the swing direction selection signal Sd output from the swing switch 59 is read, and the swing direction according to the swing direction selection signal Sd is determined. When the swing switch 59 is not operated, the previously set operation direction or the initial setting direction is adopted.

  Subsequently, the brake ECU 30 determines the swing direction in step S20. If the swing direction is the pitch direction, in step S21, the brake ECU 30 determines the pitch natural frequency of the vehicle body (pitch of the vehicle body) in step S21. An excitation command for vibrating (increasing or decreasing) the driving force of the engine 11 is transmitted at a frequency at which the directional motion is excited. In this case, the brake ECU 30 calculates a driving force waveform that vibrates (increases or decreases) the driving force at the pitch natural frequency of the vehicle body (frequency at which the motion in the pitch direction is excited), and adds information representing the calculated driving force waveform. The vibration command is transmitted to the engine ECU 10. The natural frequency in the pitch direction of the vehicle body is obtained in advance by experiments (for example, 1.7 Hz). As shown in FIG. 4, the driving force waveform is divided into a basic component and a vibration component, which are set based on the driving force and the slip rate sampled in step S14.

  For example, the basic component is set to a driving force with an acceleration slip ratio of about 10%. In addition, the frequency of the vibration component is set based on the natural frequency of the pitch, and the amplitude thereof is set to such a value that the slip ratio varies by about ± 10%. In this case, for example, from the data sampled in step S14, the driving force at which the slip rate becomes about 10%, the driving force at which the slip rate becomes about 20%, and the driving force at which the slip rate becomes 0% are estimated and driven. The force waveform may be set as described above. In addition, the structure which simplifies a process and calculates a driving force waveform by adding together the driving force (for example, maximum value) memorize | stored in step S21 and the vibration component of the preset amplitude may be sufficient. Alternatively, the process of step S14 may be omitted and the driving force may be vibrated with a preset driving force waveform.

  When the brake ECU 30 transmits an excitation command representing a driving force waveform to the engine ECU 10, the engine ECU 10 controls the driving force (driving torque) of the engine 11 according to the driving force waveform. That is, the driving force of the engine 11 is controlled by setting the driving force represented by the driving force waveform to the target value. As a result, the driving force transmitted to the ground by the driving wheels 20 vibrates (increases / decreases), a force in the front-rear direction is applied to the vehicle body, and the vehicle body swings in the pitch direction. In this case, the engine ECU 10 reports to the brake ECU 30 that the driving force is controlled according to the driving force waveform.

  In step S22, the brake ECU 30 lowers the damping force of the shock absorber with respect to the absorber ECU 40 with respect to the drive wheel 20 in which acceleration slip is detected and the wheel 20 provided at the diagonal position of the drive wheel 20. Absorber damping force reduction command for transmitting (for example, minimizing) is transmitted. When the absorber ECU 40 receives this absorber damping force reduction command, the absorber ECU 40 reduces the damping force of the designated shock absorber 41 of the wheel 20. As a result, the attenuation of the swinging motion of the vehicle in the pitch direction is reduced, and the vehicle body can be swung favorably in the pitch direction.

  The brake ECU 30 once ends the routine when the process of step S22 is performed. The brake ECU 30 repeatedly performs such processing. Therefore, the vehicle body swings in the pitch direction due to the vibration (increase or decrease) of the driving force while the state in which some of the driving wheels 20 are accelerating and slipping continues.

  On the other hand, when the swing direction is set to the roll direction in step S20, or when the swing direction is switched from the pitch direction to the roll direction, the brake ECU 30 advances the process to step S23. In step S23, the brake ECU 30 transmits an excitation command for causing the driving force to vibrate (increase or decrease) at the roll natural frequency of the vehicle body (frequency at which motion in the roll direction is excited) to the engine ECU 10. This process differs from the process of step S21 only in that the frequency for vibrating the driving force corresponds to the natural frequency of the roll, and the basic driving force waveform calculation method is the same as in step S21. It is. The natural frequency in the roll direction of the vehicle body is obtained in advance by experiments (for example, 1.2 Hz).

  When the engine ECU 10 receives the vibration command representing the driving force waveform from the brake ECU 30, the engine ECU 10 controls the driving force of the engine 11 according to the driving force waveform. That is, the driving force (driving torque) of the engine 11 is controlled by setting the driving force represented by the driving force waveform to the target value. As a result, the driving force generated by the drive wheels 20 vibrates (increases / decreases), a force in the front-rear direction is applied to the vehicle body, and the vehicle body swings in the roll direction. In this case, the engine ECU 10 reports to the brake ECU 30 that the driving force is controlled according to the driving force waveform.

  In the following step S24, the brake ECU 30 applies the damping force of the shock absorber 41 to the absorber ECU 40 with respect to the drive wheel 20 in which acceleration slip is detected and the wheel 20 provided at the diagonal position of the drive wheel 20. An absorber damping force reduction command for reducing (for example, minimizing) is transmitted. When the absorber ECU 40 receives this absorber damping force reduction command, the absorber ECU 40 reduces the damping force of the designated shock absorber 41 of the wheel 20. As a result, the attenuation of the swing motion of the vehicle in the roll direction is reduced, and the vehicle body can be swung well in the roll direction.

  Subsequently, in step S25, the brake ECU 30 transmits a mount damping force reduction command for reducing (for example, minimizing) the damping force of the variable engine mount 19 to the engine ECU 10. When the engine ECU 10 receives the mount damping force reduction command, the engine ECU 10 reduces the damping force of the variable engine mount 19. As a result, the engine 11 swings in the roll direction in the opposite phase with respect to the vehicle body, and the movement of the vehicle body in the roll direction can be promoted by its inertia. Since the engine 11 of the present embodiment is a vertical installation type, the engine 11 easily swings in the roll direction with respect to the vehicle body.

  The brake ECU 30 once ends the routine when the process of step S25 is performed. The brake ECU 30 repeatedly performs such processing. Therefore, while the state where some of the driving wheels 20 are accelerating and slipping continues, the vehicle body swings in the pitch direction or the roll direction due to the vibration (increase or decrease) of the driving force.

  According to this vehicle body vibration control routine, when a part of the drive wheels 20 floats from the ground and cannot travel, the driving force of the engine 11 is increased or decreased by the natural frequency of the pitch or the natural frequency of the roll. Therefore, the vehicle body can be swung in the pitch direction or the roll direction. Due to the swinging of the vehicle body, the floating drive wheel 20 can be temporarily grounded, and the driving force of the drive wheel 20 can be transmitted to the ground while the ground is grounded. For this reason, the escape capability from the stack state is improved.

  Further, since the damping force of the shock absorber 41 is reduced when the vehicle body is swung, the rocking of the vehicle body can be prevented from being attenuated as much as possible. Thereby, the drive wheel 20 that has floated can be pressed against the ground for a long time with a strong force.

  Furthermore, since the damping force of the variable engine mount 19 is reduced when the vehicle body is swung, the movement of the vehicle body in the roll direction can be promoted. Further, since the driver can select the swing direction (pitch direction or roll direction) of the vehicle body by operating the swing switch 59, for example, even if the vehicle body is swung in the roll direction (or pitch direction), the stack state is maintained. If it is not possible to escape, the swing switch 59 is operated to switch the swing direction, and the vehicle body can be swung in the pitch direction (or roll direction). For this reason, the ability to escape from the stack state is further improved.

  Further, since the driving force waveform when the vehicle body is vibrated is set based on the driving force when the driving wheel 20 is actually slipped by acceleration, the vehicle body can be swung efficiently.

  The vehicle body vibration control routine is executed only in a limited situation where the driver recognizes that he / she is receiving off-road driving assistance or the driver is trying to escape from the stack (S17). Not implemented during normal driving. Therefore, the vehicle body vibration control routine can be executed so as not to give the driver a sense of incongruity.

  Although the vehicle control apparatus according to the present embodiment has been described above, the present invention is not limited to the above-described embodiment and modification examples, and various modifications can be made without departing from the object of the present invention.

  For example, in the present embodiment, the swing direction of the vehicle body is configured to be switchable between the pitch direction and the roll direction, but may be configured to be fixed to either one. Further, the swing switch 59 may be omitted and the swing direction may be automatically switched.

  Moreover, in this embodiment, although applied to the vehicle of the type which drives the driving wheel 20 with the engine 11, this invention uses the electric vehicle which drives a driving wheel with a motor, a motor, and an engine together, for example. The present invention can be applied to various vehicles such as a hybrid vehicle that drives driving wheels.

  DESCRIPTION OF SYMBOLS 10 ... Engine ECU, 11 ... Engine, 13 ... Transfer, 19 ... Variable engine mount, 20 ... Wheel, 30 ... Brake ECU, 31 ... Friction brake mechanism, 31a ... Brake disc, 31b ... Brake caliper, 32 ... Brake actuator, 40 DESCRIPTION OF SYMBOLS ... Absorber ECU, 41 ... Shock absorber, 42 ... Suspension sensor, 51 ... Engine control sensor, 52 ... Accelerator sensor, 53 ... Transfer selection switch, 54 ... Brake sensor, 55 ... Wheel speed sensor, 56 ... Behavior sensor, 57 ... Steering angle sensor, 58 ... off-road selection switch, 59 ... swing switch, 60 ... crawl control switch, 70 ... CAN communication line, A ... accelerator operation amount, B ... brake operation amount, ω ... wheel speed.

Claims (1)

In a control device for a vehicle that controls a driving force generated by a driving source that drives a plurality of driving wheels,
Slip detecting means for detecting a state in which some of the plurality of driving wheels are accelerating slip;
The driving force generated by the driving source at the natural frequency at which the vehicle body resonates in the roll direction or the pitch direction when the slip detecting means detects a state where a part of the driving wheel is accelerated and slipped. A vehicle control device comprising: vibration control means for increasing or decreasing the frequency.

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