Control device for a vehicle

Abstract

A control device of a vehicle, which is able to easily escape from a stuck state under automatic escape stuck control. In a case where it is determined that the vehicle is in a stuck state, at the time when movement of the vehicle in a forward direction is stopped, the direction of the driving torque is switched from the forward direction toward the reverse direction by switching the direction of the torque imparted to the motor from the forward direction toward the reverse direction. On the other hand, in a case where it is determined that the vehicle is in a stuck state, at the time when movement of the vehicle in a reverse direction is stopped, the direction of the driving torque is switched from the reverse direction toward the forward direction by switching the direction of the torque imparted to the motor from the reverse direction toward the forward direction. Thus, compared with a case where the shift range of the power transmission device is switched, the timing of switching the direction of the driving torque is easily synchronized with movement of the vehicle in a stuck state, and sufficient speed increase can be brought about.

Description

Technical Field

[0001] This invention relates to a technology for automatically escaping from a stuck vehicle. Background Technology

[0002] Vehicle control devices are known to include a power source and a power transmission device disposed on the power transmission path between the power source and the drive wheels. For example, the vehicle escaping device described in Patent Document 1 embodies this technology. Patent Document 1 discloses a technology that automatically switches the direction of the driving force and escapes from a stuck state without relying on manual operation by the driver. The technology described in Patent Document 1 mechanically switches gears when the velocity obtained by integrating the output value of the acceleration sensor becomes zero, thereby switching the direction of the driving torque applied in the forward and reverse directions.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-202645 Summary of the Invention

[0004] When escaping from a stuck situation, after the drive wheels reach the highest point on the ramp in the direction of travel on the stuck surface, the drive torque in the forward direction is reduced, and the drive wheels simply descend from the ramp by free fall. Therefore, the vehicle decelerates due to driving resistance or sliding resistance, failing to achieve an increase in speed. In the technology described in Patent Document 1, when it is determined that the drive wheels have reached the highest point on the ramp in the direction of travel on the stuck surface, the direction of the drive torque is switched from the forward direction to the reverse direction. In the technology described in Patent Document 1, the switching of the direction of the drive torque is performed by switching the transmission's shift range (shift position) between the D range (forward travel range) and the reverse travel range (R range). However, since switching the transmission's shift range takes time, it is possible that time will be spent switching the direction of the drive torque. Therefore, under automatic escaping control, it is difficult to synchronize the timing of switching the direction of the drive torque with the vehicle's movement (e.g., sliding down the ramp in the forward direction), failing to achieve a sufficient increase in speed (increased inertial force). Automatic extrication from a stuck vehicle control is, for example, control that switches the direction of drive torque between the forward and reverse directions when the vehicle is stuck. The stuck surface is the road surface (depression) that causes the vehicle to become stuck.

[0005] The present invention was made in view of the above circumstances, and its object is to provide a control device for a vehicle that can easily detach from a stuck state under automatic detachment control.

[0006] The subject of the first invention is a vehicle control device, (a) the vehicle having a power source and a power transmission device disposed on a power transmission path between the power source and the drive wheels, wherein the control device includes: (b) a determination unit that determines whether the vehicle is in a stuck state where the drive wheels are slipping and the change in vehicle speed is small; and (c) a drive control unit that, when it is determined that the vehicle is in the stuck state, when the vehicle stops moving in the forward direction, switches the direction of the torque applied to the electric motor from the forward direction to the reverse direction, and switches the direction of the drive torque applied from the forward direction to the reverse direction; on the other hand, when the vehicle stops moving in the reverse direction, switches the direction of the torque applied to the electric motor from the reverse direction to the forward direction, and switches the direction of the drive torque applied from the reverse direction to the forward direction.

[0007] Invention Effects

[0008] According to the first invention, when it is determined that the vehicle is stuck, when the vehicle stops moving in the forward direction, the direction of the torque applied to the electric motor is switched from the forward direction to the reverse direction, and the direction of the driving torque is switched from the forward direction to the reverse direction. Conversely, when it is determined that the vehicle is stuck, when the vehicle stops moving in the reverse direction, the direction of the torque applied to the electric motor is switched from the reverse direction to the forward direction, and the direction of the driving torque is switched from the reverse direction to the forward direction. Therefore, compared to switching the gear range of the power transmission device, it is easier to synchronize the timing of switching the direction of the driving torque with the movement of the vehicle in the stuck state, resulting in a significant speed increase. Thus, under automatic escape from the stuck state control, it is easy to escape from the stuck state. Attached Figure Description

[0009] Figure 1 This is a diagram illustrating the general structure of a vehicle to which the present invention is applied, and also a diagram illustrating the main parts of the control functions used for various controls in the vehicle.

[0010] Figure 2 This diagram illustrates an example of how the motion of a vehicle stuck in a rut can be used to describe the movement of a pendulum. Figure 2 (a) indicates a situation where the drive wheels have reached a slope in the direction of travel that is impossible to climb over the stuck road surface. Figure 2 (b) indicates the state where the drive wheels have reached the slope of the road surface where the vehicle is stuck. Figure 2 (c) indicates a situation where the drive wheels have reached a slope in the reverse direction that is no longer possible to climb up the stuck road surface.

[0011] Figure 3 This diagram illustrates an example of the driving torque supplied by the electric motor under automatic traction control.

[0012] Figure 4 This is a flowchart illustrating the main parts of the control operation of the electronic control device, and also a flowchart illustrating the control operation that facilitates easy escape from a stuck vehicle state under automatic escape control.

[0013] Figure 5 It means that it has been executed. Figure 4 The flowchart shows an example of a time chart during control operation.

[0014] Figure 6 This is a diagram illustrating an example of the effect of the automatic vehicle detachment control based on this embodiment. Detailed Implementation

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0016] Example

[0017] Figure 1 This is a diagram illustrating the general structure of a vehicle 10 to which the present invention is applied, and also a diagram illustrating the main parts of the control functions used for various controls in the vehicle 10. Figure 1 In this invention, vehicle 10 includes an electric motor 12, left and right drive wheels 14, and a power transmission device 20 for transmitting power from the electric motor 12 to the drive wheels 14. The electric motor 12 is the power source of this invention. The power transmission device 20 is the power transmission device of this invention disposed on the power transmission path between the electric motor 12 and the drive wheels 14. Furthermore, the term "left and right" refers to left and right relative to the forward direction of vehicle 10.

[0018] The electric motor 12 is a known rotating electromechanical device, a so-called electric generator. The electric motor 12 is connected to the battery 32 of the vehicle 10 via an inverter 30. The torque of the electric motor 12, which is the torque of the power source, is controlled by the inverter 30, which is controlled by the electronic control device 50 described later.

[0019] The power transmission device 20 includes a reduction gear mechanism 22, an output gear 24, a differential 26, and left and right drive shafts 28. The reduction gear mechanism 22 is a gear pair having an input-side gear 22i and an output-side gear 22o meshing with the input-side gear 22i. The input-side gear 22i is connected to the electric motor 12, and the output-side gear 22o is connected to the output gear 24. The output gear 24 meshes with the ring gear 26r of the differential 26. The drive shafts 28 connect the differential 26 and the drive wheels 14.

[0020] The vehicle 10 also includes an electronic control device 50, which acts as a controller for performing various controls on the vehicle 10. The electronic control device 50 is configured, for example, as a so-called microcomputer equipped with a CPU, RAM, ROM, input / output interfaces, etc. The CPU utilizes the temporary storage function of RAM to perform signal processing according to a program pre-stored in the ROM. The electronic control device 50 is the control device of this invention.

[0021] The electronic control unit 50 is supplied with various signals based on the detection values ​​of various sensors, etc., provided by the vehicle 10. These sensors include, for example, an electric motor speed sensor 60, wheel speed sensors 62, throttle opening sensors 64, and acceleration sensors 66. Wheel speed sensors 62 include sensors corresponding to the left and right drive wheels 14 and the left and right driven wheels (not shown), respectively. The signals include, for example, electric motor speed Nm, wheel speed Nw, throttle opening θacc, and front-rear acceleration Gx. Electric motor speed Nm is the rotational speed of the electric motor 12. Wheel speed Nw is the rotational speed of the wheel. Wheel speed Nw includes drive wheel speed Nwd and driven wheel speed Nws. Drive wheel speed Nwd includes the rotational speeds of the left and right drive wheels 14 (left drive wheel speed Nwdl, right drive wheel speed Nwdr). Driven wheel speed Nws includes the rotational speeds of the left and right driven wheels (left driven wheel speed Nwsl, right driven wheel speed Nwsr). Throttle opening θacc is a signal representing the magnitude of the driver's acceleration request, specifically the amount of throttle input. Forward and backward acceleration Gx is the acceleration of vehicle 10 in the forward and backward direction.

[0022] The electronic control unit 50 outputs various command signals (such as motor control command signal Sm) to various devices (such as inverter 30) provided in the vehicle 10. The motor control command signal Sm is a command signal used to control the motor 12.

[0023] The electronic control unit 50 includes an acquisition unit 52, a determination unit 54, and a drive control unit 56 to realize various controls in the vehicle 10.

[0024] The acquisition unit 52 acquires the estimated vehicle speed Vxe based on the wheel speed Nw. The estimated vehicle speed Vxe is an estimate of the vehicle speed Vx, which is the speed of the vehicle 10. Unless otherwise specified, the vehicle speed Vx and the estimated vehicle speed Vxe have the same meaning. For example, the acquisition unit 52 acquires the lowest or second slowest value among the average driven wheel speed Nwsav and the wheel speed Nw as the estimated vehicle speed Vxe. The average driven wheel speed Nwsav is the average value of the driven wheel speeds Nws. Furthermore, in the case of an all-wheel drive vehicle, slippage may occur on any of the wheels. In the event of slippage on any of the wheels, the estimated vehicle speed Vxe can be acquired, for example, using the integral value of the front and rear acceleration Gx.

[0025] The determination unit 54 determines whether slippage has occurred on the drive wheel 14, that is, whether tire slippage has occurred. For example, the determination unit 54 determines whether tire slippage has occurred based on whether the difference between the average drive wheel speed Nwdav and the average driven wheel speed Nwsav exceeds a slippage determination threshold. Alternatively, the determination unit 54 may also determine whether tire slippage has occurred based on whether the wheel slip rate (= (Nwdav - Nwsav) / Nwdav) exceeds a slippage determination threshold. The average drive wheel speed Nwdav is the average value of the drive wheel speeds Nwd. The slippage determination thresholds are, for example, predetermined thresholds used to determine whether tire slippage has occurred. In the case of an all-wheel drive vehicle, tire slippage may also be determined based on whether the wheel angular acceleration exceeds a slippage determination threshold. The wheel angular acceleration is at least one of the rates of change of the wheel speed Nw corresponding to the wheel angular acceleration.

[0026] The drive control unit 56 calculates the driver's drive request quantity DEM for the vehicle 10 by applying the throttle opening θacc and the estimated vehicle speed Vxe to the drive request quantity diagram. The drive request quantity diagram is, for example, a pre-determined relationship used to calculate the drive request quantity DEM, which is experimentally or design-wise determined and stored beforehand. The drive request quantity DEM includes, for example, the requested drive torque Tdrvdem and the requested drive force Fdrvdem. The requested drive torque Tdrvdem is the requested value of the drive torque Tdrv, which is the torque in the drive wheel 14. The requested drive force Fdrvdem is the requested value of the drive force Fdrv, which is the force in the drive wheel 14. Unless otherwise specified, the drive torque Tdrv and the drive force Fdrv have the same meaning. The drive control unit 56 outputs a motor control command signal Sm to the inverter 30 for controlling the motor 12 to obtain the motor torque Tm that realizes the drive request quantity DEM.

[0027] Here, vehicle 10 sometimes gets stuck in sand or similar conditions. When escaping from this situation, after the drive wheel 14 reaches its highest point on the slope in the direction of travel on the stuck surface, only the drive torque Tdrv in the direction of travel is reduced, and the drive wheel 14 descends from the slope simply by free fall. Therefore, vehicle 10 decelerates due to driving resistance or vehicle sliding resistance, and cannot achieve an increase in speed. When vehicle 10 is stuck, an automatic escaping control CNase could be considered, which involves repeatedly moving vehicle 10 in both the forward and reverse directions while switching the direction of the drive torque Tdrv in the forward and reverse directions at appropriate times.

[0028] When performing automatic vehicle detachment control CNase, even if vehicle 10 cannot detach from the stuck state and slides down the slope in the forward direction, the driving torque Tdrv applied in the forward direction will be lost due to energy loss, and will not lead to amplification of inertial force. Furthermore, the road surface may be damaged at this time. In this embodiment, a method for applying a driving torque Tdrv that amplifies inertial force is proposed in the automatic vehicle detachment control CNase. Additionally, in this embodiment, regarding the signs of the driving torque Tdrv, motor torque Tm, and front-rear acceleration Gx, the forward direction of vehicle 10 is set to positive, and the reverse direction of vehicle 10 is set to negative.

[0029] Figure 2 This diagram illustrates an example of how the motion of a vehicle 10 stuck in a rut is described using the motion of a pendulum. Figure 2 (a) indicates the situation where the drive wheel 14 has reached the slope in the direction of travel that is unable to climb the road surface where the vehicle is stuck. Figure 2 (b) indicates the state where the drive wheel 14 has reached the slope of the road surface where the vehicle is stuck. Figure 2 (c) indicates the situation where the drive wheel 14 has reached the slope in the reverse direction where it is unable to climb the road surface where the vehicle is stuck.

[0030] exist Figure 2 In (a), the drive wheel 14 climbs to its highest point on the slope in the forward direction of the stuck road surface, which corresponds to the state of maximum pendulum amplitude. In this state, the acceleration of the vehicle 10 in the direction of the desired descent (i.e., the negative direction (reverse direction) acceleration (-g×sinθ) is assumed to be maximum. A force (-m×g×sinθ) is applied to the vehicle 10 to descend the slope. The vehicle speed Vx is set to zero. "g" represents the acceleration due to gravity, "θ" represents the gradient of the slope of the stuck road surface, and "m" represents the mass of the vehicle 10.

[0031] exist Figure 2 In (b), the state in which the drive wheel 14 descends the inclined plane in the direction of travel from the stuck road surface is equivalent to the state in which the amplitude of the pendulum is zero. In this state, the acceleration of the vehicle 10 is set to zero. The vehicle speed Vx is set to maximum.

[0032] exist Figure 2 In (c), the drive wheel 14 climbs to its highest point on the slope in the backward direction of the stuck road surface, which corresponds to the state of maximum pendulum amplitude. In this state, the acceleration of vehicle 10 in the direction it wants to descend the slope, i.e., the acceleration in the positive direction (forward direction) (g×sinθ), is at its maximum. A force (m×g×sinθ) is applied to vehicle 10 to descend the slope. The vehicle speed Vx is set to zero.

[0033] When the drive wheel 14 is at its highest point on the slope of the stuck road surface, the vehicle speed Vx is set to zero. When the vehicle 10 is stuck, the drive wheel 14 reaches its highest point on the slope of the stuck road surface when the vehicle 10 stops moving. In the automatic escape control CNase, the direction of the drive torque Tdrv is switched when the drive wheel 14 reaches its highest point on the slope of the stuck road surface.

[0034] The drive wheel 14 climbs to its highest point on the slope in the direction of travel on the stuck road surface (see reference). Figure 2 In case (a), the vehicle 10 intends to move in the reverse direction. Therefore, in the automatic scrambling control CNase, it is preferable to switch the drive torque Tdrv applied to the forward direction to the reverse direction. On the other hand, the drive wheel 14 climbs to its highest position on the slope in the reverse direction of the stuck road surface (see reference). Figure 2 (c) If the vehicle 10 wants to move in the forward direction, then in the automatic escape from the stalemate control CNase, it is preferable to switch the drive torque Tdrv given in the reverse direction to the forward direction.

[0035] Assuming the power transmission device 20 includes a known automatic transmission, the direction of the drive torque Tdrv can be switched by changing the shift range (shift position) between the D range (forward driving range) and the R range (reverse driving range). However, the shift range switching of an automatic transmission takes time. Therefore, in the automatic vehicle detachment control CNase, it is difficult to complete the shift range switching synchronously with the moment when the drive wheel 14 climbs to its highest point on the slope of the stuck road surface, thus failing to provide a sufficient speed increase.

[0036] Vehicle 10 includes an electric motor 12 as a power source. Therefore, in vehicle 10, by reversing the positive and negative of the electric motor torque Tm without switching the forward and reverse directions in the power transmission device 20, the direction of the driving torque Tdrv applied in the automatic slack-free control CNase can be switched. The driving torque Tdrv applied in the automatic slack-free control CNase is achieved by the electric motor torque Tm. The drive control unit 56 switches the direction of the driving torque Tdrv applied in the forward and reverse directions by reversing the positive and negative of the electric motor torque Tm.

[0037] Figure 3 This diagram illustrates an example of the drive torque Tdrv imparted by the motor torque Tm in the CNase automatic vehicle detachment control system. Figure 3 In this process, the direction of the driving torque Tdrv is switched by reversing the positive and negative values ​​of the motor torque Tm. Figure 3 The state of "A" in the text is equivalent to Figure 2 (a) state. Figure 3 The state of "C" in the text is equivalent to Figure 2 (c) State. If we define the state where the drive wheel 14 has climbed to its highest point on the slope in the backward direction of the stuck surface, then by switching the direction of the torque Tm applied to the motor from the backward direction to the forward direction, and switching the direction of the drive torque Tdrv applied to the drive torque from the backward direction to the forward direction (refer to time t1a). The state where the drive wheel 14 has climbed to its highest point on the slope in the backward direction of the stuck surface is the state where the vehicle 10 stops moving backward. If we define the state where the drive wheel 14 has climbed to its highest point on the slope in the forward direction of the stuck surface, then by switching the direction of the torque Tm applied to the motor from the forward direction to the backward direction, and switching the direction of the drive torque Tdrv applied to the drive torque from the forward direction to the backward direction (refer to time t2a). The state where the drive wheel 14 has climbed to its highest point on the slope in the forward direction of the stuck surface is the state where the vehicle 10 stops moving forward. In this embodiment, when the direction of the motor torque Tm is set to the forward direction, the motor torque Tm is set to a positive value; when the direction of the motor torque Tm is set to the reverse direction, the motor torque Tm is set to a negative value (negative torque). By implementing the automatic vehicle detachment control CNase, the direction of the driving torque Tdrv is repeatedly switched, allowing the vehicle 10 to detach from the stuck state.

[0038] The determination unit 54 determines whether the vehicle 10 is stuck. A stuck state is defined as a state where the drive wheels 14 are slipping and the change in the vehicle's speed Vx is small. When the determination unit 54 determines that tire slippage has occurred, it determines whether the vehicle 10 is stuck based on whether the rate of change of the vehicle's speed Vx is below a stuck-state determination threshold. The stuck-state determination threshold is, for example, a predetermined threshold used to determine whether tires are stuck.

[0039] The determination unit 54 determines whether the drive wheel 14 has climbed to its highest point on the slope in the forward direction of the stuck road surface, that is, whether the movement of the vehicle 10 in the forward direction has stopped. The determination unit 54 determines whether the movement of the vehicle 10 in the forward direction has stopped based on whether the vehicle speed Vx becomes zero when the vehicle 10 moves in the forward direction (that is, a predetermined zero determination value). The movement of the vehicle 10 in the forward direction stops when the vehicle speed Vx is determined to be zero when the vehicle 10 moves in the forward direction. The determination unit 54 also determines whether the drive wheel 14 has climbed to its highest point on the slope in the backward direction of the stuck road surface, that is, whether the movement of the vehicle 10 in the backward direction has stopped. The determination unit 54 determines whether the movement of the vehicle 10 in the backward direction has stopped based on whether the vehicle speed Vx becomes zero when the vehicle 10 moves in the backward direction. The movement of the vehicle 10 in the backward direction stops when the vehicle speed Vx is determined to be zero when the vehicle 10 moves in the backward direction.

[0040] When the determination unit 54 determines that the vehicle 10 is stuck, the drive control unit 56, when the vehicle 10 stops moving in the forward direction, switches the direction of the torque Tm applied to the motor from the forward direction to the reverse direction, and switches the direction of the drive torque Tdrv from the forward direction to the reverse direction. Conversely, when the determination unit 54 determines that the vehicle 10 is stuck, the drive control unit 56, when the vehicle 10 stops moving in the reverse direction, switches the direction of the torque Tm applied to the motor from the reverse direction to the forward direction, and switches the direction of the drive torque Tdrv from the reverse direction to the forward direction.

[0041] If the driving torque Tdrv applied in the automatic vehicle detachment control CNase is too large, it may cause damage to the road surface where the vehicle is stuck. The driving torque Tdrv applied when the determination unit 54 determines that the vehicle 10 is stuck is a predetermined torque that is unlikely to cause damage to the road surface where the vehicle is stuck.

[0042] In the CNase automatic vehicle detachment control system, the direction of the driving torque Tdrv is switched by reversing the positive and negative values ​​of the motor torque Tm, thus enabling rapid switching. However, abrupt changes in the driving torque Tdrv can potentially damage the road surface where the vehicle is stuck. The gradient of the change in driving torque Tdrv during the transition between the forward and reverse directions is a predetermined gradient that is unlikely to cause damage to the road surface (see reference). Figure 3 ).

[0043] When vehicle 10 is stuck, the automatic detachment control CNase causes vehicle 10 to move repeatedly in the forward and reverse directions, thus easily compacting the stuck surface. Even as the change in driving torque Tdrv increases with the compaction of the stuck surface, the stuck surface is difficult to break. The absolute value of the gradient of the change in driving torque Tdrv during the transition between the forward and reverse directions is set to a larger value as the switching between the forward and reverse directions is repeated.

[0044] Figure 4 It is a flowchart illustrating the main part of the control operation of the electronic control device 50, and also a flowchart illustrating the control operation that facilitates the vehicle's escape from a stuck state in the automatic vehicle escape control CNase, for example, repeated execution.

[0045] exist Figure 4 First, in step S10 (hereinafter omitted), corresponding to the function of the determination unit 54, it is determined whether the vehicle 10 is stuck. If the determination in S10 is negative, the process ends. If the determination in S10 is positive, in step S20 (corresponding to the function of the drive control unit 56), the automatic detachment control CNase is executed. In the automatic detachment control CNase, when the drive wheel 14 climbs to its highest point on the slope of the stuck road surface (when the vehicle 10 stops moving), the direction of the drive torque Tdrv is switched between the forward and reverse directions by reversing the positive and negative of the motor torque Tm. That is, the drive force Fdrv is switched to the driving force for getting stuck. Next, in step S30 (corresponding to the function of the determination unit 54), it is determined whether the vehicle 10 has escaped the stuck state. If the determination in S30 is negative, the process returns to step S20. If the judgment in S30 is confirmed, in S40 corresponding to the function of the drive control unit 56, the automatic detachment from the stuck vehicle control CNase is terminated, and normal control is returned. Under normal control, for example, control of the drive torque Tdrv based on the throttle opening θacc is performed.

[0046] Figure 5 It means that it has been executed. Figure 4 The flowchart shows an example of a timeline diagram during control operation. Figure 5In the diagram, time t1b represents the moment when vehicle 10 is determined to be stuck. If it is determined to be stuck, the automatic detachment control CNase causes vehicle 10 to move repeatedly in the forward and reverse directions. This gradually strengthens the road surface. Therefore, the absolute value of the gradient of the driving torque Tdrv during the transition between the forward and reverse directions is gradually set to a larger value. By implementing the automatic detachment control CNase and repeatedly switching the direction of the driving torque Tdrv, vehicle 10 is freed from the stuck state (refer to time t2b).

[0047] Figure 6 This is a diagram illustrating an example of the effect of the automatic vehicle detachment control CNase based on this embodiment. Figure 6 This represents the experimental results showing the relationship between the number of times vehicle 10 repeatedly moves in the forward and backward directions using the automatic vehicle detachment control CNase and the detachable height on the stuck road surface. Figure 6 In the automatic vehicle detachment control CNase, when the direction of the driving torque Tdrv is switched between the forward and reverse directions, the detachment height on the stuck road surface is higher compared to the case where the driving torque Tdrv is only applied in the forward direction. Therefore, it is easier to detach from the stuck situation.

[0048] As described above, according to this embodiment, when it is determined that the vehicle 10 is stuck, when the vehicle 10 stops moving in the forward direction, the direction of the torque Tm applied to the motor is switched from the forward direction to the reverse direction, and the direction of the driving torque Tdrv is switched from the forward direction to the reverse direction. On the other hand, when it is determined that the vehicle 10 is stuck, when the vehicle 10 stops moving in the reverse direction, the direction of the torque Tm applied to the motor is switched from the reverse direction to the forward direction, and the direction of the driving torque Tdrv is switched from the reverse direction to the forward direction. Therefore, for example, compared to the case of switching the shift range of the power transmission device 20, it is easier to synchronize the timing of switching the direction of the driving torque Tdrv with the movement of the vehicle 10 when it is stuck, which can bring about a sufficient speed increase. Therefore, in the automatic escape from stuck control CNase, it is easy to escape from the stuck state.

[0049] Furthermore, in the automatic vehicle detachment control CNase of this embodiment, by utilizing the negative torque of the motor torque Tm, the vehicle speed Vx can be increased, thereby improving traction. Moreover, by using the negative torque of the motor torque Tm, regenerative energy is utilized, thus providing an advantage in terms of electricity.

[0050] Furthermore, according to this embodiment, the gradient of the change in the driving torque Tdrv during the transition between the forward and reverse directions is a predetermined gradient of magnitude that is unlikely to cause damage to the road surface where the vehicle is stuck. Therefore, in the automatic vehicle detachment control CNase, damage to the road surface where the vehicle is stuck is suppressed.

[0051] Furthermore, according to this embodiment, the absolute value of the gradient of the change in the driving torque Tdrv during the transition between the forward and reverse directions is set to a large value as the switching between the forward and reverse directions is repeated. Therefore, depending on the compaction of the road surface, the change in driving torque Tdrv becomes larger, making it less likely to damage the road surface and simultaneously enabling a rapid increase in speed.

[0052] Furthermore, according to this embodiment, the driving torque Tdrv applied when the vehicle 10 is determined to be stuck is a predetermined torque of a magnitude that is unlikely to cause damage to the road surface. Therefore, in the automatic vehicle detachment control CNase, damage to the stuck road surface is suppressed.

[0053] Furthermore, according to this embodiment, when the vehicle 10 stops moving in the forward direction, it means when the vehicle speed Vx is determined to be zero while the vehicle 10 is moving in the forward direction. When the vehicle 10 stops moving in the reverse direction, it means when the vehicle speed Vx is determined to be zero while the vehicle 10 is moving in the reverse direction. Therefore, in the automatic vehicle scrambling control CNase, the direction of the driving torque Tdrv is appropriately switched.

[0054] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention can also be applied to other methods.

[0055] For example, in the foregoing embodiments, the power source may be an engine in addition to the electric motor 12. In short, the power source only needs to include at least the electric motor 12.

[0056] Furthermore, in the aforementioned embodiments, in the automatic vehicle detachment control CNase, the timing for switching the direction of the applied drive torque Tdrv was exemplified by determining that the vehicle speed Vx is zero, but this method is not limited to this. Hereinafter, another method for determining the timing of switching the direction of the applied drive torque Tdrv will be illustrated.

[0057] When the drive wheel 14 has climbed to its highest point on the slope of the stuck road, the front-rear acceleration Gx is set to its maximum or minimum value (refer to...). Figure 2Therefore, the sign of the acceleration Jx is reversed. Acceleration Jx is the acceleration (jump), which is the time derivative of the preceding and following acceleration Gx, i.e., the proportion of the change in preceding and following acceleration Gx relative to time. When vehicle 10 is stuck, the drive wheel 14 climbs to its highest point on the slope of the stuck road surface when the sign of acceleration Jx reverses. In the automatic detachment control CNase, the direction of the driving torque Tdrv can also be switched at the time of the sign of the preceding and following acceleration Gx and the reversal of the sign of acceleration Jx. Regarding the sign of acceleration Jx, the forward direction of vehicle 10 is set to a positive value, and the reverse direction of vehicle 10 is set to a negative value.

[0058] The acquisition unit 52 acquires the forward and backward acceleration Gx based on the detection value of the accelerometer 66. The acquisition unit 52 calculates the time derivative of the forward and backward acceleration Gx. The acquisition unit 52 acquires the calculated time derivative of the forward and backward acceleration Gx as the jerk Jx.

[0059] The drive wheel 14 climbs to its highest point on the slope in the direction of travel on the stuck road surface (reference). Figure 2 In case (a), the forward and backward acceleration Gx is negative (minimum), and the sign of the acceleration Jx reverses from negative to positive. In this case, the vehicle 10 moves in the reverse direction, so in the automatic detachment control CNase, it is preferable to switch the drive torque Tdrv applied to the forward direction to the reverse direction. On the other hand, the drive wheel 14 climbs to its highest position on the slope in the reverse direction of the stuck road surface (see reference). Figure 2 (c) In this case, the forward and backward acceleration Gx is positive (maximum), and the sign of the jerk Jx reverses from positive to negative. In this case, the vehicle 10 moves in the forward direction, so in the automatic escape from the stalemate control CNase, it is preferable to switch the drive torque Tdrv given to the reverse direction to the forward direction.

[0060] Furthermore, the above is only one embodiment, and the present invention can be implemented with various changes and improvements based on the knowledge of those skilled in the art.

[0061] Symbol Explanation

[0062] 10-Vehicle, 12-Electric motor (power source), 14-Drive wheel, 20-Power transmission device, 50-Electronic control device (control device), 54-Decision unit, 56-Drive control unit.

Claims

1. A vehicle control device, characterized in that, The vehicle includes: a power source, comprising an electric motor; and a power transmission device disposed on the power transmission path between the power source and the drive wheels. The vehicle control device includes: a determination unit that determines whether the vehicle is in a stuck state where the drive wheels are slipping and the change in vehicle speed is small; and The drive control unit, when determining that the vehicle is stuck, switches the direction of the torque applied to the electric motor from the forward direction to the reverse direction when the vehicle stops moving in the forward direction, and switches the direction of the drive torque applied from the forward direction to the reverse direction. On the other hand, when the vehicle stops moving in the reverse direction, it switches the direction of the torque applied to the electric motor from the reverse direction to the forward direction, and switches the direction of the drive torque applied from the reverse direction to the forward direction.

2. The vehicle control device according to claim 1, characterized in that, The gradient of the change in the driving torque during the transition between the forward and reverse directions is a predetermined gradient of the magnitude of road surface damage that is unlikely to cause the vehicle to get stuck.

3. The vehicle control device according to claim 2, characterized in that, The absolute value of the changing gradient is set to a larger value as the forward and backward directions are repeatedly switched.

4. The vehicle control device according to claim 1, characterized in that, The driving torque applied when the vehicle is determined to be in the stuck state is a predetermined torque of a magnitude that is unlikely to cause damage to the road surface that would be the cause of the stuck state.

5. The vehicle control device according to any one of claims 1 to 4, characterized in that, The vehicle stops moving in the forward direction when the vehicle's speed is determined to be zero while it is moving in the forward direction, and the vehicle stops moving in the reverse direction when the vehicle's speed is determined to be zero while it is moving in the reverse direction.

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