Control device

Abstract

To provide a control device that can quickly deal with variation in required braking force, while preventing a vehicle from running backward even when a state of a road surface varies, in performing vehicle-stop control in the vehicle equipped with a rotary electric machine.SOLUTION: A control device, which controls a vehicular driving device equipped with a rotary electric machine, executes, at the same time, feed-forward control in which target torque set to a negative value is set as a target value and feed-back control in which torque of the rotary electric machine is controlled so that rotation speed of the rotary electric machine is made to get close to target rotation speed, when stopping the running vehicle, in a state where the rotary electric machine rotates together with a wheel. When required braking force varies, the control device changes the target torque in the feed-forward control and the target rotation speed in the feed-back control, according to change in the required braking force.SELECTED DRAWING: Figure 5

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 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the stopping control in Patent Document 1 merely controls the torque of the rotating electric machine using a feedforward method. Therefore, if the gradient of the road surface or surface friction changes, for example, the vehicle may move in reverse. Also, if the braking force required by the driver changes during stopping control, the system may not be able to adequately respond to the change, which may cause the driver to feel uncomfortable.

[0006] Therefore, when performing stopping control on a vehicle equipped with a rotating electric machine, it is desirable to be able to quickly respond to changes in the required braking force while making it difficult for the vehicle to move backward 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 is stopped from a running state with the rotating electric machine rotating in conjunction with the wheels, a pre-stop control is executed in which a feedforward control is executed in which a target torque set to a negative value according to a required braking force is set as a target value, and a feedback control is executed in which the torque of the rotating electric machine is controlled so that the rotational speed of the rotating electric machine approaches a gradually decreasing target rotational speed, a control device that, when the required braking force changes while the pre-stop control is being executed, changes the target torque in the feedforward control and the target rotation speed in the feedback control in accordance with the change in the required braking force;

[0008] According to this configuration, when a traveling vehicle is about to stop, by executing pre-stop control, the torque of the rotating electric machine can be quickly brought closer to a negative target torque through feedforward control, thereby appropriately decelerating the vehicle. Furthermore, by simultaneously executing feedback control, the rotational speed of the rotating electric machine can be reduced toward zero according to the target rotational speed in the feedback control. Even if a change in road surface conditions (e.g., gradient, surface friction, etc.) causes the rotational speed to deviate 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, thereby making it less likely for the vehicle to move backward. If the required braking force changes during execution of such pre-stop control, both the target torque in the feedforward control and the target rotational speed in the feedback control are changed in accordance with the change in the required braking force, allowing for a rapid response to the change in the required braking force. As a result, when a stop control is being performed on a vehicle equipped with a rotating electric machine, it is possible to quickly respond to a change in the required braking force while making it less likely for the vehicle to move backward even when 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 (normal operation) [Figure 4] Control block diagram for determining torque command for a rotating electrical machine [Figure 5] Time chart of each part during stopping control (when the required braking force changes) [Figure 6] 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 vehicle V on which the vehicle drive device 3 is mounted is equipped with various components necessary for safely driving the vehicle V with passengers on board. The vehicle V is equipped with, for example, an accelerator pedal, a brake pedal P, a steering wheel, a suspension, wheels W, etc. In particular, the vehicle V of this embodiment is equipped with a hydraulic brake B that operates in conjunction with the operation of the brake pedal P and functions to stop the rotation of the wheels W.

[0016] 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.

[0017] 2, the control device 1 includes an integrated control unit 11, a rotating electrical 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.

[0018] 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 operation amount (accelerator opening) of an accelerator pedal provided on the vehicle V. The fourth sensor 44 detects the operation amount of a brake pedal P provided on the vehicle V.

[0019] 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.

[0020] The integrated control unit 11 performs control that integrates various controls necessary for the vehicle V to travel as a whole of the vehicle V. The integrated 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).

[0021] In this embodiment, the integrated control unit 11 calculates the torque (required braking torque) required to decelerate the vehicle V based on, for example, the amount of brake operation detected by the fourth sensor 44. The integrated control unit 11 determines the share of the required braking torque to be contributed by the hydraulic brake B provided on the vehicle and the share of the negative torque output by the rotating electric machine 31.

[0022] 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.

[0023] 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.

[0024] The stop control unit 13 performs stop control to gradually decelerate and stop the vehicle V while it is running. The stop 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 stop control is executed when, while the vehicle V is running, it is determined that the vehicle V will stop within a predetermined time, for example, because the driver applies the brakes or the vehicle speed decreases due to road resistance or the like. In this embodiment, the stop control unit 13 executes initial deceleration control, first pre-stop control, and second pre-stop control as stop controls. After executing the initial deceleration control, the stop control unit 13 executes the first pre-stop control, and then executes the second pre-stop control. The stop control unit 13 cooperates with the rotating electric machine control unit 12 to execute the initial deceleration control, the first pre-stop control, and the second pre-stop control. In this embodiment, at least the first pre-stop control corresponds to the "pre-stop control."

[0025] The initial deceleration control is executed after the start condition is met while the vehicle speed is higher than the first reference speed Vs1. Here, the start condition is, for example, that the operation amount (braking operation amount) of the brake pedal P is equal to or greater than the reference operation amount. The reference operation amount is set to an operation amount of the brake pedal P that is expected to cause the vehicle V to stop within a predetermined time thereafter. Furthermore, the first reference speed Vs1 is set to, for example, 3 to 7 km / h. Note that the contents of the start condition and the magnitude of the first reference speed Vs1 mentioned here are merely examples and may be changed as appropriate depending on required specifications, etc.

[0026] In the initial deceleration control, no braking operation is performed by the hydraulic brake B, and only regenerative braking is performed by the rotating electric machine 31. In this initial deceleration control, control is executed to make the torque of the rotating electric machine 31 follow a target torque set to a negative value. Here, the negative target torque is set to the required braking torque. As shown in FIG. 3, the initial deceleration control is executed by feedforward control with the target torque set to a negative value as the target value. By executing such initial deceleration control, it is possible to appropriately decelerate the vehicle V while efficiently regenerating power in the rotating electric machine 31, thereby improving electricity efficiency.

[0027] The first pre-stop control is executed during the period from when the vehicle speed becomes equal to or less than the first reference speed Vs1 until the vehicle speed is higher than a second reference speed Vs2 that is less than the first reference speed Vs1. Here, the second reference speed Vs2 is set to, for example, 1 to 2 km / h. Note that the magnitude of the second reference speed Vs2 mentioned here is merely an example and may be changed as appropriate depending on the required specifications, etc.

[0028] In the first pre-stop control, in addition to regenerative braking by the rotating electric machine 31, a braking operation is performed by the hydraulic brake B. In the first pre-stop control, the braking torque by the hydraulic brake B, which was zero before (i.e., during the initial deceleration control), is gradually increased, and conversely, the regenerative braking torque by the rotating electric machine 31 is gradually decreased. The increase in braking torque by the hydraulic brake B and the decrease in regenerative braking torque by the rotating electric machine 31 are balanced, and the sum of the braking torque by the hydraulic brake B and the regenerative braking torque by the rotating electric machine 31 matches the required braking torque. This makes it possible to provide a hydraulic brake feeling while ensuring the required braking torque.

[0029] In the first pre-stop 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 the gradually decreasing target rotation speed. In this first pre-stop control, feedforward control is executed in combination, with the target torque set to a negative value according to the portion of the required braking force contributed by regenerative braking of the rotating electric machine 31 as the target value, and feedback control is executed in combination, with the torque of the rotating electric machine 31 being controlled so that the rotation speed of the rotating electric machine 31 approaches the gradually decreasing target rotation speed.

[0030] For this reason, the control device 1 of this embodiment includes a feedforward controller (FF controller) 51 and a feedback controller (FB controller) 52, as shown in Fig. 4. The feedforward controller 51 calculates a torque target value (shown as "FF command value" in Fig. 3) according to the portion of the required braking force that is due to regenerative braking of the rotating electric machine 31 (regenerative required torque). The feedback controller 52 calculates an adjustment torque (shown as "FB control value" in Fig. 3) for canceling out the deviation of the actual rotation speed from the target rotation speed of the rotating electric machine 31. The torque command for the rotating electric machine 31 is the sum of these two values.

[0031] The feedback control in the first pre-stop control can be, for example, proportional control (P control), proportional-integral control (PI control), proportional-integral-derivative control (PID control), etc. Among these, the control including an integral term, i.e., proportional-integral control (PI control) or proportional-integral-derivative control (PID control), is preferred because it can eliminate steady-state deviation caused by disturbances and bring the rotation speed of the rotating electric machine 31 closer to the target rotation speed with higher accuracy.

[0032] By executing feedforward control in the first pre-stop control, the torque of the rotating electric machine 31 can be quickly brought closer to the target torque, and the share of the regenerative braking of the rotating electric machine 31 (required regenerative torque) can be quickly output. Furthermore, by executing feedback control in the first pre-stop control, even if there is variation in the hydraulic pressure of the hydraulic brake B (and therefore variation in the braking torque due to this), variation in the hydraulic brake feeling can be kept small. If there is variation in the hydraulic pressure of the hydraulic brake B, this will appear as a deviation between the actual rotation speed and the target rotation speed of the rotating electric machine 31, and therefore, by using feedback control to adjust the torque of the rotating electric machine 31 to cancel out this deviation, an appropriate total required braking force can be ensured.

[0033] As shown in FIG. 4 , the control device 1 of this embodiment further includes an upper / lower limit guard 53 in addition to the feedforward controller 51 and the feedback controller 52. The upper / lower limit guard 53 applies upper and lower limit guards to a combination (referred to as a “raw torque command”) of the torque target value (FF command value) calculated by the feedforward controller 51 and the adjustment torque (FB control value) calculated by the feedback controller 52. That is, when the raw torque command is greater than the upper limit value, the upper / lower limit guard 53 outputs a value equal to the upper limit value as the torque command, and when the raw torque command is smaller than the lower limit value, the upper / lower limit guard 53 outputs a value equal to the lower limit value as the torque command. Furthermore, when the raw torque command is between the upper and lower limit values, the upper / lower limit guard 53 outputs the raw torque command as is as the torque command.

[0034] In this embodiment, the upper and lower limit values ​​of the torque command for the rotary electric machine 31 are set based on at least the torque target value (FF command value) in the feedforward control and the braking torque by hydraulic brake B that is gradually increased in the first pre-stop control. More specifically, the upper limit value is calculated by adding a value obtained by multiplying the braking torque by hydraulic brake B by a certain amount of variation (percentage) to the torque target value (FF command value) in the feedforward control. The lower limit value is calculated by subtracting a value obtained by multiplying the braking torque by hydraulic brake B by a certain amount of variation (percentage) from the torque target value (FF command value) in the feedforward control. The amount of variation is set to a value of, for example, 0.1 to 0.3 depending on the required specifications, etc.

[0035] If the upper limit value of the torque command is "Tu", the lower limit value of the torque command is "Tl", the torque target value calculated by the feedforward controller 51 is "Tf", the braking torque by hydraulic brake B is "Tb", and the setting variation amount is "α", the upper limit value Tu and lower limit value Tl of the torque command are calculated according to the following equations. Tu = Tf + Tb α Tl = Tf - Tb α

[0036] By providing a limiter for the torque of the rotating electric machine 31 after adjustment by feedback control, it is possible to prevent a situation in which excessive torque is output and the vehicle suddenly stops, even if, for example, an error is included in the actual rotational speed of the rotating electric machine 31 detected by the first sensor 41. Alternatively, it is possible to prevent a situation in which the necessary torque is not secured and the complete stop of the vehicle V is delayed.

[0037] The target rotation speed of the rotating electric machine 31 in the first pre-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 deceleration control (i.e., when the vehicle speed has decreased to the first reference speed Vs1). 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 deceleration 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 deceleration control is used as an initial value, and so as to change over time at the same time rate as the actual rotation acceleration of the rotating electric machine 31 at that time.

[0038] The second pre-stop control is executed during a period when the vehicle speed is equal to or lower than the second reference speed Vs2. In the second pre-stop control, regenerative braking by the rotating electric machine 31 is switched over to braking operation by the hydraulic brake B. In the second pre-stop control, the braking torque by the hydraulic brake B, which was relatively small before (i.e., during the first pre-stop control), is increased in a short period of time, and conversely, the regenerative braking torque by the rotating electric machine 31 is reduced in a short period of time. This allows for a clearer hydraulic brake feeling, and ultimately allows the hydraulic brake B to reliably maintain the vehicle V in a stopped state.

[0039] In the second pre-stop 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. In this second pre-stop control, feedforward control is executed in combination, with the target value being a target torque that is set to approach zero while taking a negative value, and feedback control is executed in combination to adjust the torque of the rotating electric machine 31 so that the rotation speed of the rotating electric machine 31 approaches the target rotation speed that decreases toward zero. In this second pre-stop control, as in the first pre-stop control described above, both the feedforward controller 51 and the feedback controller 52 are used.

[0040] Furthermore, the upper and lower limit guards 53 set upper and lower limits on the torque command of the rotary electric machine 31. In this embodiment, the upper and lower limit values ​​of the torque command in the second pre-stop control are set based on the torque target value (FF command value) in the feedforward control and the upper and lower limit values ​​at the end of the first pre-stop control. More specifically, the upper limit value is calculated by adding to the torque target value (FF command value) in the feedforward control a value that gradually decreases from an initial value that is the difference between the upper limit value and the torque target value (FF command value) at the end of the first pre-stop control to zero at the end of the second pre-stop control. Furthermore, the lower limit value is calculated by subtracting from the torque target value (FF command value) in the feedforward control a value that gradually decreases from an initial value that is the difference between the lower limit value and the torque target value (FF command value) at the end of the first pre-stop control to zero at the end of the second pre-stop control.

[0041] By executing feedforward control in the second pre-stop control, the torque of the rotating electric machine 31 is quickly brought close to zero, gradually eliminating regenerative braking by the rotating electric machine 31, and braking operation can be switched to hydraulic brake B early. Furthermore, by executing feedback control in the second pre-stop control, the actual rotational speed of the rotating electric machine 31 decreases while maintaining a positive value. Therefore, when the vehicle V is stopped with the rotating electric machine 31 rotating in conjunction with the wheels W, the wheels W also decrease while maintaining forward rotation. Therefore, even if the road surface conditions (e.g., gradient, surface friction, etc.) change or there is a slight delay in the rise of the hydraulic pressure of the hydraulic brake B, it is possible to make it less likely that the vehicle V will move in reverse.

[0042] The target rotation speed of the rotating electric machine 31 in the second pre-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 first pre-stop control (i.e., when the vehicle speed has decreased to the second reference speed Vs2). 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 first pre-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 first pre-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 has decreased to zero, it is maintained at zero.

[0043] During vehicle stop control (e.g., during first pre-stop control), the driver may depress or release the brake pedal P, causing a change in the required braking force (see FIG. 5). In such a case, in this embodiment, the target torque in the feedforward control and the target rotational speed in the feedback control are changed in accordance with the change in the required braking force. In this embodiment, when the required braking force changes, the braking torque by the hydraulic brake B is output according to the initial schedule, and the amount corresponding to the change in the required braking force is absorbed by the regenerative braking torque by the rotating electric machine 31. As described above, the target torque in the feedforward control is calculated in accordance with the portion of the required braking force that is borne by the regenerative braking of the rotating electric machine 31 (regenerative required torque), and is therefore automatically recalculated in accordance with the change in the required braking force.

[0044] On the other hand, the target rotation speed in the feedback control needs to be actively recalculated in response to changes in the required braking force. In this embodiment, the stopping control unit 13 periodically sets the target rotation speed in the feedback control based on at least the required braking force. More specifically, the stopping control unit 13 sequentially determines the target rotation speed in the feedback control at a set cycle based on the target rotation speed in the previous cycle, the actual rotation acceleration of the rotating electric machine 31, and the change rate of the required braking force.

[0045] The set period is set based on, for example, the clock frequency of a control board that is the core of the control device 1. The actual rotational acceleration of the rotating electric machine 31 is calculated in the control device 1 (rotating electric machine control unit 12) based on the actual rotational speed of the rotating electric machine 31 detected by the first sensor 41. The required braking force is calculated in the control device 1 (integrated control unit 11) based on the brake operation amount detected by the fourth sensor 44.

[0046] The required braking force remains unchanged until it actually changes. In this case, the actual rotational acceleration of the rotating electric machine 31 can also be considered to remain unchanged. In this embodiment, the actual rotational acceleration and the required braking force of the rotating electric machine 31 at the start of the first pre-stop control are stored as initial values, and are used to calculate the target rotational speed in the feedback control, thereby reducing the calculation load.

[0047] More specifically, if the initial value of the actual rotational acceleration of the rotating electric machine 31 is "A0", the initial value of the required braking force is "B0", the target rotational speed in the nth cycle is "N(n)", the required braking force in the nth cycle is "B(n)", and the time for one cycle is "ΔT", the target rotational speed in feedback control is calculated according to the following formula. N(n)=N(n-1)+A0·(B(n) / B0)·ΔT

[0048] With this configuration, the target rotation speed for each set cycle can be easily calculated using only the required braking force in the nth cycle as a substantial variable, allowing for a quick response when the required braking force changes. Furthermore, since the target torque in feedforward control is automatically recalculated in response to changes in the required braking force, and the target torque and target rotation speed are appropriately changed, it is possible to quickly respond to changes in the required braking force.

[0049] The processing procedure of the vehicle stopping control, which includes the initial deceleration control, the first pre-stop control, and the second pre-stop control, will be described with reference to Fig. 6. When the vehicle V is traveling under normal control and the start condition is met (step #01: Yes), the initial deceleration control is executed (#02). In the initial deceleration control, with the hydraulic brake B inactive, control is executed to make the torque of the rotating electrical machine 31 follow a target torque set according to the required braking torque.

[0050] When the vehicle speed is decreasing due to the execution of the initial deceleration control and the vehicle speed becomes equal to or less than the first reference speed Vs1 (#03: Yes, time t1, t11), the first pre-stop control is initiated. In the first pre-stop control, the braking torque by the hydraulic brake B is gradually increased, and the regenerative braking torque by the rotating electric machine 31 is gradually decreased (#04). Then, feedforward control, which sets a target torque corresponding to the share of regenerative braking by the rotating electric machine 31 as a target value, and feedback control, which controls the torque of the rotating electric machine 31 so that the rotational speed of the rotating electric machine 31 approaches the gradually decreasing target rotational speed, are executed together (#05).

[0051] If the required braking force changes while the first pre-stop control is being executed (time t12 to t13), the target torque in the feedforward control and the target rotation speed in the feedback control are changed in accordance with the change in the required braking force, as described above.

[0052] The vehicle speed continues to decrease while the first pre-stop control is being executed, and when the vehicle speed becomes equal to or less than the second reference speed Vs2 under such circumstances (#06: Yes, time t2, t14), the second pre-stop control is initiated. In the second pre-stop control, the braking torque by the hydraulic brake B is rapidly increased, and the regenerative braking torque by the rotating electric machine 31 is rapidly decreased (#07). Then, feedforward control is executed in which the target torque is set to a target value that gradually approaches zero using the torque command value at the end of the first pre-stop control as the initial value, and feedback control is executed in which the torque of the rotating electric machine 31 is controlled so that the rotational speed of the rotating electric machine 31 approaches the target rotational speed that decreases toward zero (#08).

[0053] When the time during which the vehicle speed remains zero exceeds a certain period of time (#09: Yes), the vehicle V is considered to have come to a complete stop, and the stopping control is terminated.

[0054] Other Embodiments (1) In the above embodiment, an example has been described in which the torque command of the rotating electric machine 31 is limited by an upper limit and a lower limit. However, the present invention is not limited to such a configuration. For example, the torque command of the rotating electric machine 31 may be limited only by an upper limit value, or conversely, may be limited only by a lower limit value. Alternatively, such upper and lower limits may not be set at all.

[0055] (2) In the above embodiment, the target rotation speed of the feedback control in the first pre-stop control is calculated using the initial value "B0" of the actual rotation acceleration of the rotating electric machine 31, assuming that the actual rotation acceleration is constant. However, the present invention is not limited to such a configuration, and the target rotation speed may be calculated using the actual rotation acceleration of the previous cycle, which is calculated based on the actual rotation speed of the rotating electric machine 31 that is measured periodically.

[0056] (3) In the above embodiment, a configuration has been described in which the change rate of the required braking force is used to calculate the target rotational speed of the feedback control in the first pre-stop control. However, the present invention is not limited to such a configuration. For example, the target rotational speed may be calculated using the change rate of the required acceleration, which is one of the physical quantities corresponding to the required braking force. Furthermore, it is not necessary to use the ratio before and after the change in the required braking force. For example, the change rate of the target rotational speed may be calculated by multiplying the result of adding the change rate of the required acceleration to the actual rotational acceleration one cycle ago by the time for one cycle, and then adding this to the actual rotational speed one cycle ago to calculate the target rotational speed.

[0057] (4) In the above embodiment, the target torque in the feedforward control and the target rotation speed in the feedback control are changed when the required braking force changes during the first pre-stop control. However, the present invention is not limited to such a configuration, and similar control may be performed when the required braking force changes during the second pre-stop control.

[0058] (5) In the above embodiment, an example has been described in which the second pre-stop control performs 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 present invention is not limited to such a configuration, and the second pre-stop control may perform only feedback control of the rotation speed of the rotating electric machine 31.

[0059] (6) In the above embodiment, an example has been described in which the vehicle required torque and the required braking torque are calculated by the integrated 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.

[0060] (7) 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 control device 1 is not limited to such a configuration, and 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.

[0061] (8) 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.

[0062] Summary of the embodiment To summarize the above, the control device according to the present disclosure preferably has the following configurations.

[0063] A control device (1) for controlling a vehicle drive device (3) including a rotating electric machine (31), When the vehicle (V) stops from a traveling state while the rotating electric machine (31) rotates in conjunction with the wheels (W), a pre-stop control is executed in which a feedforward control is executed in which a target torque, which is set to a negative value according to a required braking force, is set as a target value, and a feedback control is executed in which a torque of the rotating electric machine (31) is controlled so that the rotation speed of the rotating electric machine (31) approaches a gradually decreasing target rotation speed. When the required braking force changes during execution of the pre-stop control, the target torque in the feedforward control and the target rotation speed in the feedback control are changed in accordance with the change in the required braking force.

[0064] According to this configuration, when a traveling vehicle (V) is about to stop, by executing pre-stop control, the torque of the rotating electric machine (31) can be quickly brought closer to a negative target torque through feedforward control, thereby appropriately decelerating the vehicle (V). Furthermore, by simultaneously executing feedback control, the rotational speed of the rotating electric machine (31) can be reduced toward zero in accordance with the target rotational speed in the feedback control. Even if a change in road surface conditions (e.g., gradient, surface friction, etc.) causes the rotational speed to deviate from the target rotational speed, the torque of the rotating electric machine (31) is controlled to reduce the deviation and bring the rotational speed of the rotating electric machine (31) closer to the target rotational speed. This makes it difficult for the vehicle (V) to move backward. If the required braking force changes during execution of such pre-stop control, both the target torque in the feedforward control and the target rotational speed in the feedback control are changed in accordance with the change in the required braking force, thereby enabling a rapid response to the change in the required braking force. As a result, when stopping control is being performed on a vehicle (V) equipped with a rotating electric machine (31), it is possible to make it difficult for the vehicle (V) to move backward even when the road surface conditions change, while also being able to quickly respond to changes in the required braking force.

[0065] In one embodiment, It is preferable that the target rotation speed in the feedback control is determined sequentially at a set cycle based on the target rotation speed of the previous cycle, the actual rotation acceleration of the rotating electric machine (31), and the required braking force or a change ratio of a physical quantity corresponding thereto.

[0066] According to this configuration, the target rotation speed for each set cycle in feedback control can be determined relatively easily using the required braking force or the change ratio of the physical quantity corresponding to it (a unitless value) as one of the variables.

[0067] In one embodiment, an actual rotational acceleration of the rotating electric machine (31) before the change in the required braking force is regarded as unchanged, and initial values ​​of the actual rotational acceleration of the rotating electric machine (31) and the required braking force or physical quantities corresponding thereto are stored; The target rotation speed in the feedback control is calculated using the following formula: N(n)=N(n-1)+A0·(B(n) / B0)·ΔT [where: N(n) is the target rotation speed in the nth period, A0 is an initial value of the actual rotational acceleration of the rotating electric machine (31), B0 is an initial value of the required braking force or a physical quantity corresponding thereto, B(n) is the required braking force or a physical quantity corresponding thereto in the nth cycle, ΔT is the time for one period.] It is preferable to calculate it according to the following formula.

[0068] According to this configuration, by storing an initial value assuming that the actual rotational acceleration of the rotating electric machine (31) does not change until the required braking force changes, the target rotational speed for each set cycle can be easily calculated using only the required braking force in the nth cycle or a physical quantity corresponding thereto as the substantial variable.

[0069] In one embodiment, The vehicle drive device (3) is mounted on a vehicle (V) equipped with a hydraulic brake (B), In the pre-stop control, the regenerative braking torque by the rotating electric machine (31) is gradually reduced, and the braking torque by the hydraulic brake (B) is gradually increased. It is preferable to limit the torque of the rotating electric machine (31) after adjustment by the feedback control within a range between an upper limit value and a lower limit value determined according to the braking torque by the hydraulic brake (B) based on the target torque in the feedforward control.

[0070] According to this configuration, a hydraulic brake feeling can be provided by combining the braking operation of the hydraulic brake (B). In this case, even if there is variation in the hydraulic pressure for operating the hydraulic brake (B), this appears as a deviation between the actual rotation speed and the target rotation speed of the rotating electric machine (31), and the torque of the rotating electric machine (31) is controlled to reduce this deviation, thereby minimizing variation in the hydraulic brake feeling. Furthermore, by setting upper and lower limit values ​​for the torque of the rotating electric machine (31) after adjustment by feedback control, it is possible to prevent situations in which excessive torque is output or the required torque is not secured, even if, for example, an error is included in the detection system.

[0071] 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]

[0072] 1: control device, 3: vehicle drive device, 11: integrated 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, 51: feedforward controller, 52: feedback controller, 53: upper and lower limit guard, B: hydraulic brake, P: brake pedal, V: vehicle, Vs1: first reference speed, Vs2: second reference speed, W: wheel

Claims

1. A control device that controls a vehicle drive device equipped with a rotating electric machine, When the vehicle is stopped from a running state with the rotating electric machine rotating in conjunction with the wheels, a pre-stop control is executed in which a feedforward control is executed in which a target torque set to a negative value according to a required braking force is set as a target value, and a feedback control is executed in which the torque of the rotating electric machine is controlled so that the rotational speed of the rotating electric machine approaches a gradually decreasing target rotational speed, a control device that, when the required braking force changes while the pre-stop control is being executed, changes the target torque in the feedforward control and the target rotation speed in the feedback control in accordance with the change in the required braking force.

2. 2. The control device according to claim 1, wherein the target rotation speed in the feedback control is determined sequentially at a set cycle based on the target rotation speed of one cycle before, an actual rotation acceleration of the rotating electric machine, and a change ratio of the required braking force or a physical quantity corresponding thereto.

3. an actual rotational acceleration of the rotating electric machine before the change in the required braking force is regarded as unchanged, and initial values ​​of the actual rotational acceleration of the rotating electric machine and the required braking force or physical quantities corresponding thereto are stored; The target rotation speed in the feedback control is calculated using the following formula: N(n)=N(n-1)+A0・(B(n) / B0)・ΔT [where: N(n) is the target rotation speed in the nth period, A0 is the initial value of the actual rotational acceleration of the rotating electric machine, B0 is an initial value of the required braking force or a physical quantity corresponding thereto, B(n) is the required braking force or a physical quantity corresponding thereto in the nth cycle, ΔT is the time for one period. The control device according to claim 2 , wherein the calculation is performed in accordance with the following formula:

4. the vehicle drive device is mounted on a vehicle equipped with a hydraulic brake, In the pre-stop control, the regenerative braking torque by the rotary electric machine is gradually reduced, and the braking torque by the hydraulic brake is gradually increased, 4. The control device according to claim 1, wherein the torque of the rotating electric machine after adjustment by the feedback control is limited to a range between an upper limit value and a lower limit value determined in accordance with a braking torque by the hydraulic brake, with the target torque in the feedforward control as a reference.

Images