Control device

Abstract

To prevent increase or decrease in deceleration and backward running of a vehicle even when a state of a road surface varies, in performing stop control in the vehicle provided with a rotary electric machine.SOLUTION: A control device, which controls a vehicular driving device equipped with a rotary electric machine, executes specific vehicle-stop control, after a start condition is satisfied until a vehicle stops, when the running vehicle stops. The control device controls torque of the rotary electric machine so that rotation speed of the rotary electric machine gets closer to target rotation speed that decreases toward zero, in the specific vehicle-stop control.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control device. [Background technology]

[0002] For example, vehicles equipped with rotating electric machines as a driving force source for wheels, such as electric vehicles and hybrid vehicles, are in use. An example of a control device for controlling such a vehicle drive device is disclosed in Japanese Patent Application Laid-Open No. 2022-99702 (Patent Document 1).

[0003] The control device (control device 10) of Patent Document 1, when a vehicle (vehicle 100) stops from a running state, outputs a braking / driving torque to a rotating electric machine (rotating electric machine 141) to cause the rotating electric machine to regenerate, thereby improving electricity efficiency. At this time, the control device controls the rotating electric machine to stop by changing the torque of the rotating electric machine along a predetermined stopping waveform just before the vehicle stops. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-99702

[0005] However, the stopping control in Patent Document 1 merely controls the torque of the rotating electric machine using a feedforward method, which can cause the vehicle deceleration to change or the vehicle to move in reverse when, for example, the gradient of the road surface or the surface friction changes. Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, when performing stop control on a vehicle equipped with a rotating electric machine, it is desirable to make it difficult for the deceleration of the vehicle to increase or decrease or for the vehicle to move in reverse even when the road surface conditions change. [Means for solving the problem]

[0007] The control device according to the present disclosure includes: A control device that controls a vehicle drive device equipped with a rotating electric machine, When the vehicle stops from a running state with the rotating electric machine rotating in conjunction with the wheels, specific stopping control is executed to control the torque of the rotating electric machine so that the rotational speed of the rotating electric machine approaches a target rotational speed that decreases toward zero from the time a start condition is met until the vehicle stops.

[0008] According to this configuration, by executing specific stop control when a traveling vehicle is stopped, the rotational speed of the rotating electric machine can be reduced toward zero according to the target rotational speed in the specific stop control. Even if the road surface conditions (e.g., gradient, surface friction, etc.) change and the rotational speed deviates from the target rotational speed, the torque of the rotating electric machine is controlled to reduce the deviation and bring the rotational speed of the rotating electric machine closer to the target rotational speed, making it less likely that the vehicle will decelerate or move in reverse. Therefore, when stop control is being performed on a vehicle equipped with a rotating electric machine, it is possible to make it less likely that the vehicle will decelerate or move in reverse even if the road surface conditions change.

[0009] Further features and advantages of the techniques according to the present disclosure will become more apparent from the following description of exemplary and non-limiting embodiments, which proceeds with reference to the drawings. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a vehicle equipped with a vehicle drive device and a control device according to an embodiment; [Figure 2] Control device block diagram [Figure 3] Time chart for each part during stopping control [Figure 4] Flowchart showing the processing procedure for vehicle stop control DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the control device will be described with reference to the drawings. As shown in Fig. 1, this control device 1 is a control device for a vehicle drive device that controls a vehicle drive device 3 mounted on a vehicle V. In this embodiment, the vehicle V is described as an electric vehicle (electrically driven vehicle) as an example. That is, the control device 1 of this embodiment is a control device for an electric vehicle drive device.

[0012] In the following description, the term "rotating electric machine" is used as a concept that includes motors (electric motors), generators (electric generators), and motor-generators that function as both motors and generators as needed.

[0013] As shown in FIG. 1, the vehicle drive device 3 includes a rotating electric machine 31, a power transmission device 32, and an output shaft 33. These are housed in a case 35. The rotating electric machine 31 functions as a driving force source for the wheels W. As is well known, the rotating electric machine 31 includes a stator fixed to the case 35, which is a non-rotating member, and a rotor rotatably supported radially inside the stator. The rotating electric machine 31 receives a supply of electric power from an electric storage device (not shown) for power running, or supplies electric power generated by the inertial force of the vehicle or the like to the electric storage device for storage.

[0014] The power transmission device 32 is provided in a power transmission path connecting the rotating electric machine 31 and the wheels W, and transmits the driving force of the rotating electric machine 31 to the wheels W. The power transmission device 32 is configured to include, for example, a speed change mechanism or a differential gear mechanism, and may also be configured to include, for example, a counter drive mechanism. The output shafts 33 function as output members of the vehicle drive device 3, and are provided in pair on the left and right. Each of the pair of output shafts 33 is drivingly connected to the wheels W via, for example, a drive shaft.

[0015] The control device 1 functions as a core for controlling the operation of each part of the vehicle drive device 3. The control device 1 mainly controls the operation of the rotating electric machine 31 as a driving force source for the wheels W. The control device 1 is configured to include, for example, an inverter circuit including a switching element, a smoothing capacitor, a control board, etc., and may also be configured to include, for example, a boost circuit, etc. In the illustrated example, the control device 1 is provided integrally with a case 35 of the vehicle drive device 3.

[0016] 2, the control device 1 includes a traveling control unit 11, a rotating electric machine control unit 12, and a stopping control unit 13. Each of these functional units is configured by software (programs) stored in a storage medium such as a memory, or by hardware such as a separately provided arithmetic circuit, or by both. The functional units are configured to be able to exchange information with each other. The control device 1 is also configured to be able to acquire information on the detection results of various sensors (in this example, a first sensor 41 to a fourth sensor 44) provided in each part of the vehicle V.

[0017] The first sensor 41 detects the rotational speed of the rotating electric machine 31 (specifically, the rotor) or a rotating member that rotates integrally with the rotating electric machine 31 (for example, a transmission input member when the power transmission device 32 includes a transmission mechanism). The second sensor 42 detects the rotational speed of the output shaft 33 or a rotating member that rotates integrally with the output shaft 33 (for example, wheels W). The control device 1 can calculate the vehicle speed (travel speed of the vehicle V) based on the detection result by the second sensor 42. Alternatively, the second sensor 42 may directly detect the vehicle speed. The third sensor 43 detects the amount of operation of an accelerator pedal (accelerator opening) provided on the vehicle V. The fourth sensor 44 detects the amount of operation of a brake pedal provided on the vehicle V.

[0018] The control device 1 can also calculate the rotational acceleration, which is the rate of change of the rotational speed of each rotating member detected by the first sensor 41 and the second sensor 42, based on the rotational speed of each rotating member detected by the first sensor 41 and the second sensor 42.

[0019] The traveling control unit 11 performs control that integrates various controls necessary for the vehicle V to travel as a whole vehicle V. The traveling control unit 11 calculates the torque required to drive the vehicle V (vehicle required torque) based on, for example, vehicle speed information calculated based on the detection result by the second sensor 42 and accelerator opening information detected by the third sensor 43. If the rotating electric machine 31 is the only driving force source for the wheels W as in this embodiment, the vehicle required torque becomes the torque required of the rotating electric machine 31 (rotating electric machine required torque).

[0020] In this embodiment, the traveling control unit 11 calculates the torque (required braking torque) required to decelerate the vehicle V based on, for example, the brake operation amount detected by the fourth sensor 44. The traveling control unit 11 determines the share of the required braking torque to be contributed by the hydraulic brake provided on the vehicle and the share of the negative torque output by the rotating electric machine 31.

[0021] The rotating electric machine control unit 12 controls the rotating electric machine 31. The rotating electric machine control unit 12 can execute torque control and rotational speed control of the rotating electric machine 31 according to the running state of the vehicle. The torque control of the rotating electric machine 31 is a control that commands a target torque (for example, a torque according to the above-mentioned rotating electric machine required torque or braking torque) to the rotating electric machine 31 and makes the output torque of the rotating electric machine 31 follow the target torque. The torque control is typically executed by feedforward control.

[0022] The rotational speed control of the rotating electric machine 31 is a control that commands a target rotational speed to the rotating electric machine 31 and adjusts the output torque so that the rotational speed of the rotating electric machine 31 follows the target rotational speed. The rotational speed control is typically performed by feedback control. In the rotational speed control of the rotating electric machine 31, the rotating electric machine control unit 12 can set a target value for the output torque and perform feedforward control, while also setting a target value for the rotational speed and performing feedback control.

[0023] The stopping control unit 13 performs stopping control to gradually decelerate and stop the vehicle V while it is running. The stopping control is executed when the vehicle V stops from a running state with the rotating electric machine 31 rotating in conjunction with the wheels W. The stopping control is executed when, while the vehicle V is running, for example, the driver applies the brakes or the vehicle speed decreases due to road resistance or the like, and it is determined that the vehicle V will stop within a predetermined time. The stopping control unit 13 of this embodiment executes initial stopping control and specific stopping control as stopping controls. The stopping control unit 13 executes the specific stopping control after executing the initial stopping control. The stopping control unit 13 executes the initial stopping control and the specific stopping control in cooperation with the rotating electric machine control unit 12.

[0024] The initial stop control is executed during a period from when the first start condition is satisfied until when the second start condition is satisfied (the period from time t1 to t2 in FIG. 3). Here, in this embodiment, the first start condition is that the vehicle speed is equal to or less than a predetermined first reference speed Vs1. The first reference speed Vs1 is set to, for example, 3 to 7 km / h. The second start condition is that the vehicle speed is equal to or less than a second reference speed Vs2 that is set to a value less than the first reference speed Vs1. The second reference speed Vs2 is set to, for example, 1 to 2 km / h. In this embodiment, the second start condition corresponds to the "start condition," and the second reference speed Vs2 corresponds to the "set value." Note that the magnitudes of the first reference speed Vs1 and the second reference speed Vs2 mentioned here are merely examples and may be changed as appropriate depending on required specifications, etc.

[0025] In the initial stop control, control is executed to make the torque of the rotating electric machine 31 follow a target torque that is set to a negative value. The negative target torque here is set based on the share of the rotating electric machine 31 that is required to cover the required braking torque. As shown in FIG. 3, the initial stop control is executed by feedforward control that sets the target torque that is set to a negative value as a target value. By executing such initial stop control, it is possible to appropriately decelerate the vehicle V while causing the rotating electric machine 31 to regenerate, thereby improving electricity efficiency.

[0026] The specific stopping control is executed during the period from when the second start condition is satisfied until the vehicle comes to a stop (the period after time t2 in FIG. 3). In the specific stopping control, control is executed to adjust the torque of the rotating electric machine 31 so that the rotation speed of the rotating electric machine 31 approaches a target rotation speed that decreases toward zero. As shown in FIG. 3, the specific stopping control is executed mainly by feedback control that adjusts the torque of the rotating electric machine 31 so as to reduce the deviation between the target rotation speed that decreases toward zero and the actual rotation speed (actual rotation speed) of the rotating electric machine 31 at each point in time.

[0027] The specific stopping control, which is a feedback control, can be, for example, proportional control (P control), proportional integral control (PI control), proportional integral derivative control (PID control), or the like.

[0028] By executing such specific stopping control, when the vehicle V is decelerated by the negative torque of the rotating electric machine 31, the actual rotational speed of the rotating electric machine 31 decreases while maintaining a positive value. Therefore, when the vehicle V is stopped in a state in which the rotating electric machine 31 rotates in conjunction with the wheels W, the wheels W also decrease while maintaining positive rotation. Therefore, even if the road surface conditions (e.g., gradient, surface friction, etc.) change, it is possible to make it less likely that the vehicle V will move in reverse.

[0029] The target rotation speed of the rotating electric machine 31 in the specific stop control is set based on at least one of the actual rotation speed and the actual rotation acceleration of the rotating electric machine 31 at the end of the initial stop control (i.e., when the second start condition is met). In this embodiment, the target rotation speed is set based on both the actual rotation speed and the actual rotation acceleration of the rotating electric machine 31 at the end of the initial stop control. As shown in FIG. 3, the target rotation speed is set so that the actual rotation speed of the rotating electric machine 31 at the end of the initial stop control is used as an initial value, and so that it changes over time at the same time rate as the actual rotation acceleration of the rotating electric machine 31 at that time. Furthermore, the target rotation speed is set so that after it decreases to zero, it is maintained at zero.

[0030] If the target rotation speed is set so that it decreases to zero at a uniform time change rate, the time change rate of the actual rotation speed of the rotating electric machine 31 also becomes less likely to change regardless of the road surface condition. Therefore, even if the road surface condition changes, it is possible to make it less likely that the deceleration of the vehicle V will increase or decrease.

[0031] The specific stopping control may be performed only by the above-described feedback control, but in this embodiment, feedforward control and feedback control are performed in combination, as shown in Fig. 3. That is, in the specific stopping control, feedforward control, which sets a target torque set to a value equal to or less than zero as a target value, and feedback control, which adjusts the torque of the rotating electric machine 31 so as to reduce the deviation between a target rotation speed that decreases toward zero and the actual rotation speed of the rotating electric machine 31 at each point in time, are performed in combination. With this configuration, it is possible to quickly bring the torque of the rotating electric machine 31 close to the target torque to appropriately decelerate the vehicle V, and to make it difficult for the deceleration of the vehicle V to increase or decrease, or for the vehicle V to move in reverse, even when the road surface condition changes.

[0032] The processing procedure of the vehicle stopping control, including the initial stopping control and the specific stopping control, will be described with reference to Fig. 4. In this example, the vehicle V is traveling under normal control (step #01), and the vehicle speed is gradually decreasing due to, for example, the accelerator being released. In the normal control, control is executed to make the torque of the rotating electric machine 31 follow a predetermined target torque, and feedforward control is executed with the target torque as a target value.

[0033] When the vehicle speed is gradually decreasing and becomes equal to or less than the first reference speed Vs1 (#02: Yes, time t1), initial stop control is initiated. In the initial stop control, in order to more actively decelerate the vehicle V, the target torque for torque control of the rotating electric machine 31 is set to a negative value (#03). In this embodiment, this negative target torque is set to decrease from zero at a first decrease rate, as shown in FIG. 3, then decrease at a second decrease rate that is smaller than the first decrease rate, and then maintain a predetermined value (for example, a value near the maximum negative torque that the rotating electric machine 31 can output). In the initial stop control, feedforward control is executed in which the target torque is used as the target value for the torque of the rotating electric machine 31 (#04).

[0034] After time t1, the initial stop control causes the vehicle speed to decrease more rapidly. When the vehicle speed eventually becomes equal to or less than the second reference speed Vs2 (#05: Yes, time t2), the specific stop control is initiated. In the specific stop control, the control mode of the rotating electric machine 31 is set to rotational speed control, and the target rotational speed of the rotating electric machine 31 is set to decrease toward zero (#06), so that the vehicle V gradually decelerates while maintaining forward travel and comes to a complete stop. The target rotational speed here is set to an initial value that is the actual rotational speed of the rotating electric machine 31 when the vehicle speed reaches the second reference speed Vs2, and is set to change over time at the same rate of change as the actual rotational acceleration of the rotating electric machine 31 at that time. In the specific stop control, feedback control is executed to adjust the torque of the rotating electric machine 31 so as to reduce the deviation between the target rotational speed and the actual rotational acceleration of the rotating electric machine 31 (#07).

[0035] In the specific stopping control of this embodiment, as described above, feedforward control is executed in addition to feedback control. In this feedforward control, the target value of the torque of the rotating electric machine 31 is set to increase toward zero at a constant rate of change and then maintain zero. In the specific stopping control, feedforward control is executed in which the target torque is set as the target value of the torque of the rotating electric machine 31, and at the same time, feedback control is executed in which the torque of the rotating electric machine 31 is adjusted so as to reduce the deviation between the target rotational speed and the actual rotational acceleration of the rotating electric machine 31.

[0036] By executing such specific stopping control, the torque of the rotating motor 31 can be quickly brought closer to the target torque, thereby appropriately decelerating the vehicle V, while making it less likely that the deceleration rate of the vehicle V will increase or decrease or that the vehicle will move in reverse even if the road surface conditions (e.g., gradient, surface friction, etc.) change.

[0037] Furthermore, by gradually increasing the torque of the rotating electric machine 31 toward zero, it is possible to reduce or eliminate the twist that occurred in the power transmission path from the rotating electric machine 31 to the wheels W during the previous torque control. From this perspective, it is preferable that the second reference speed Vs2 is set to a speed that ensures the time required to eliminate the twist in the power transmission path before the vehicle V comes to a stop during the specific stop control.

[0038] When the time during which the vehicle speed remains zero exceeds a certain period of time (#08: Yes), the vehicle V is considered to have come to a complete stop, and the stopping control is terminated.

[0039] Other Embodiments (1) In the above embodiment, an example has been described in which the specific stopping control executes both feedforward control of the torque of the rotating electric machine 31 and feedback control of the rotation speed of the rotating electric machine 31. However, the specific stopping control is not limited to such a configuration, and only feedback control of the rotation speed of the rotating electric machine 31 may be executed.

[0040] (2) In the above embodiment, a configuration has been described as an example in which the target rotation speed of the rotating electric machine 31 in the specific stop control is set based on both the actual rotation speed and the actual rotation acceleration of the rotating electric machine 31 at the end of the initial stop control. However, the present invention is not limited to such a configuration, and the target rotation speed may be set based on only one of the actual rotation speed and the actual rotation acceleration of the rotating electric machine 31 at the end of the initial stop control. For example, the actual rotation speed of the rotating electric machine 31 at the end of the initial stop control may be set as an initial value, and the target rotation speed may be set to change over time at a time change rate close to the actual rotation acceleration of the rotating electric machine 31 at that time. Furthermore, the slope of the target rotation speed may change in a stepwise manner.

[0041] (3) In the above embodiment, the specific stopping control is executed after the initial stopping control. However, the present invention is not limited to such a configuration, and the execution of the initial stopping control is not essential. In this case, the vehicle V may be decelerated by hydraulic control of a hydraulic brake provided on the vehicle V to reduce the vehicle speed to equal to or less than the second reference speed Vs2.

[0042] (4) In the above embodiment, a configuration has been described in which the first start condition for starting the execution of the initial stop control and the second start condition for starting the execution of the specific stop control are determined in relation to the vehicle speed. However, the present invention is not limited to such a configuration, and the first start condition and the second start condition may be determined in relation to the rotational speed of the rotating electric machine 31. Alternatively, the first start condition and the second start condition may be determined in relation to the rotational speed of a rotating member (e.g., a transmission input member, a countershaft, a differential input gear, etc., depending on the configuration of the power transmission device 32) that is interlocked with the rotating electric machine 31.

[0043] (5) In the above embodiment, an example has been described in which the vehicle required torque and the required braking torque are calculated by the driving control unit 11 provided in the control device 1. However, the present invention is not limited to such a configuration, and for example, the vehicle required torque and the required braking torque may be calculated by a vehicle ECU provided separately from the control device 1, and the control device 1 may receive this information from the vehicle ECU and perform various controls.

[0044] (6) In the above embodiment, the control device 1 is described as an example of a configuration in which the object to be controlled by the control device 1 is a drive device for an electric vehicle (electrically driven vehicle) that has only a rotating electric machine 31 as a drive power source for the wheels W. However, the present invention is not limited to such a configuration, and the control device 1 can also be used to control a drive device for a hybrid vehicle that has an internal combustion engine in addition to the rotating electric machine 31 as a drive power source for the wheels W.

[0045] (7) The configurations disclosed in the above-described embodiments (including the above-described embodiments and other embodiments; the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction occurs. Regarding other configurations, the embodiments disclosed in this specification are illustrative in all respects and can be appropriately modified within the scope of the present disclosure.

[0046] Summary of the embodiment To summarize the above, the control device according to the present disclosure preferably has the following configurations.

[0047] A control device (1) for controlling a vehicle drive device (3) including a rotating electric machine (31), When the vehicle (V) stops from a running state while the rotating electric machine (31) rotates in conjunction with the wheels (W), specific stopping control is executed to control the torque of the rotating electric machine (31) so that the rotation speed of the rotating electric machine (31) approaches a target rotation speed that decreases toward zero from the time a start condition is met until the vehicle stops.

[0048] According to this configuration, by executing specific stop control when a traveling vehicle (V) is stopped, the rotation speed of the rotating electric machine (31) can be reduced toward zero in accordance with the target rotation speed in the specific stop control. Even if the road surface condition (e.g., gradient, surface friction, etc.) changes and the rotation speed deviates from the target rotation speed, the torque of the rotating electric machine (31) is controlled to reduce the deviation and bring the rotation speed of the rotating electric machine (31) closer to the target rotation speed. This makes it difficult for the deceleration of the vehicle (V) to increase or decrease, or for the vehicle (V) to move in reverse. Therefore, when the vehicle (V) equipped with the rotating electric machine (31) is performing stop control, it is possible to make it difficult for the deceleration of the vehicle (V) to increase or decrease, or for the vehicle (V) to move in reverse, even if the road surface condition changes.

[0049] In one embodiment, before the start condition is satisfied, an initial stop control is executed to make the torque of the rotating electric machine (31) follow a target torque set to a negative value; It is preferable to set the target rotation speed in the specific stop control based on at least one of the rotation speed and the rotation acceleration of the rotating electric machine (31) when the start condition is satisfied.

[0050] According to this configuration, by executing the initial stop control until the start condition is satisfied, the rotating electric machine (31) is caused to output negative torque to decelerate the vehicle (V) while causing the rotating electric machine (31) to perform regeneration. Furthermore, since the target rotation speed in the specific stop control that is started after the start condition is satisfied is set based on at least one of the rotation speed and the rotation acceleration of the rotating electric machine (31) when the start condition is satisfied, it is possible to minimize changes in the behavior of the vehicle (V) when the control mode is shifted from the initial stop control to the specific stop control.

[0051] In one embodiment, During execution of the specific stopping control, it is preferable to simultaneously execute feedforward control, the target value of which is a target torque set to a value equal to or less than zero.

[0052] According to this configuration, the torque of the rotating electric machine (31) can be quickly brought closer to the target torque by the feedforward control, while the specific stopping control, which is a feedback control, can make it difficult for the deceleration of the vehicle (V) to increase or decrease or for the vehicle (V) to move in reverse even when the road surface conditions change as described above.

[0053] In one embodiment, The start condition preferably includes a condition that the vehicle speed, or the rotation speed of the rotating electric machine (31) or a rotational member linked to the rotating electric machine (31) becomes equal to or less than a set value.

[0054] According to this configuration, specific stopping control is executed when the vehicle speed is low, thereby reducing the possibility of a discrepancy between the driver's operation and the vehicle (V) behavior due to feedback control that brings the rotational speed of the rotating electric machine (31) closer to the target rotational speed.

[0055] It is sufficient for the control device according to the present disclosure to achieve at least one of the above-described effects. [Explanation of symbols]

[0056] 1: control device, 3: vehicle drive device, 11: travel control unit, 12: rotating electric machine control unit, 13: stopping control unit, 31: rotating electric machine, 32: power transmission device, 33: output shaft, 35: case, 41: first sensor, 42: second sensor, 43: third sensor, 44: fourth sensor, V: vehicle, W: wheel

Claims

1. A control device that controls a vehicle drive device equipped with a rotating electric machine, A control device that, when a vehicle stops from a running state while the rotating electric machine is rotating in conjunction with the wheels, executes specific stopping control that controls the torque of the rotating electric machine so that the rotational speed of the rotating electric machine approaches a target rotational speed that decreases toward zero from the time a start condition is met until the vehicle stops.

2. before the start condition is satisfied, an initial stop control is executed to make the torque of the rotary electric machine follow a target torque that is set to a negative value; The control device according to claim 1 , wherein the target rotation speed in the specific stop control is set based on at least one of the rotation speed and the rotation acceleration of the rotating electric machine when the start condition is met.

3. The control device according to claim 1 or 2, wherein, during execution of the specific stopping control, feedforward control is also executed, with a target torque set to a value equal to or less than zero as a target value.

4. The control device according to claim 1 or 2, wherein the start condition includes a condition that a vehicle speed, a rotational speed of the rotating electric machine, or a rotational member linked to the rotating electric machine is equal to or lower than a set value.

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