Regenerative cooperation control device

Abstract

To make it possible to suppress fluctuations in deceleration of a vehicle due to execution of switching control.SOLUTION: A regenerative cooperation control device comprises: a switching control unit M17 which, under a situation where regenerative braking force is applied to a vehicle, executes switching control for switching the regenerative braking force to friction braking force; and a correction unit M19 which, when the switching control is being executed, executes correction processing for correcting the braking force having a higher response speed, of the regenerative braking force and the friction braking force, so that the magnitude of a difference between deceleration of the vehicle and target deceleration becomes small.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Patent Document 1 discloses a regenerative braking cooperative control device that controls the regenerative braking force and friction braking force applied to a vehicle. When the vehicle speed falls below a predetermined speed while regenerative braking force is being applied, this regenerative braking cooperative control device executes switching control to gradually decrease the regenerative braking force and gradually increase the friction braking force. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO2010 / 128652 Summary of the Invention [Problem to be solved by the invention]

[0004] The response speeds of the regenerative braking force and the frictional braking force are different, so that the sum of the actual value of the regenerative braking force and the actual value of the frictional braking force varies during execution of the switching control, which may cause the deceleration of the vehicle to fluctuate. [Means for solving the problem]

[0005] A regenerative cooperative control device for solving the above problem is a device applied to a vehicle including a regenerative braking device that applies a regenerative braking force to the vehicle and a friction braking device that applies a friction braking force to the vehicle. The regenerative cooperative control device includes a switching control unit that executes switching control to switch the regenerative braking force to the friction braking force under a condition in which the regenerative braking force is applied to the vehicle, and a correction unit that executes a correction process to correct the braking force with a high response speed out of the regenerative braking force and the friction braking force when the switching control is being executed so that the magnitude of the difference between the deceleration of the vehicle and a target deceleration is reduced. Effect of the Invention

[0006] The regenerative cooperative control device has an effect of suppressing fluctuations in the deceleration of the vehicle caused by the execution of switching control. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a vehicle equipped with a regenerative coordination control device according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing a functional configuration of the regenerative coordination control device of FIG. [Diagram 3] FIG. 3 is a map showing the relationship between the target deceleration and the starting vehicle speed of the switching control. [Figure 4] FIG. 4 is a map for determining the increase amount of the friction braking force command value when the preliminary switching control is executed. [Diagram 5] FIG. 5 is a flowchart showing a process flow when applying a braking force to the vehicle in the regenerative coordination control device of FIG. [Figure 6] FIG. 6 is a flowchart showing a process flow when switching control is executed in the regenerative coordination control device of FIG. [Figure 7] FIG. 7 is a flowchart showing a flow of processing in the regenerative coordination control device of FIG. 1 while the vehicle is stopped. [Figure 8] FIG. 8 is a timing chart when the vehicle is stopped by applying a braking force. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of a regenerative cooperative control device will be described below with reference to Figs. FIG 1 illustrates a vehicle 10 equipped with a regenerative cooperative control device 100. The vehicle 10 includes a brake operating member 11, a plurality of wheels 12, a plurality of friction brakes 20, a friction braking device 30, a motor generator 40, and a plurality of sensors. The brake operating member 11 is a member that is operated by the driver when decelerating the vehicle 10. An example of the brake operating member 11 is a brake pedal. In FIG 1, only one wheel 12 and one friction brake 20 are illustrated among the plurality of wheels 12 and friction brakes 20.

[0009] <Friction brake> The multiple friction brakes 20 each operate to apply a friction braking force to the corresponding wheel 12. The friction brakes 20 have a wheel cylinder 21, a rotating body 22, and a friction material 23. The rotating body 22 rotates integrally with the wheel 12. Therefore, the friction material 23 is pressed against the rotating body 22, thereby applying a friction braking force to the wheel 12. The higher the fluid pressure in the wheel cylinder 21, the greater the force pressing the friction material 23 against the rotating body 22. Therefore, with the friction brake 20, the higher the fluid pressure in the wheel cylinder 21, the greater the friction braking force that can be applied to the wheel 12.

[0010] <Friction braking device> The friction braking device 30 has a discharge source 31 that discharges brake fluid. Examples of the discharge source 31 include an electric pump and an electric cylinder. The brake fluid discharged from the discharge source 31 is supplied to the wheel cylinder 21, thereby applying a friction braking force to the wheel 12.

[0011] <Motor generator> The motor generator 40 is a power source for the vehicle 10. When the motor generator 40 functions as an electric motor, a driving force is applied to the wheels 12. Of the driving force, the driving force in the rotational direction of the wheels 12 when the vehicle 10 is moved forward is referred to as a "forward direction driving force". Of the driving force, the driving force in the rotational direction of the wheels 12 when the vehicle 10 is moved backward is referred to as a "reverse direction driving force". The motor generator 40 can also function as a generator. In this case, a regenerative braking force corresponding to the amount of power generated by the motor generator 40 is applied to the vehicle 10. In other words, the motor generator 40 functions as a regenerative braking device that applies regenerative braking force to the vehicle 10, and also functions as a driving device that can apply driving force to the wheels 12 of the vehicle 10. The motor generator 40 also corresponds to a "braking / driving device".

[0012] <Sensor> The multiple sensors output detection signals according to the detection results to the regenerative cooperative control device 100. The multiple sensors include a brake sensor 51, multiple wheel speed sensors 52, an acceleration sensor 53, and a motor angle sensor 54. The brake sensor 51 detects operation-related information related to the operation of the brake operating member 11 by the driver. The brake sensor 51 may be a stroke sensor that detects the amount of operation of the brake operating member 11 by the driver as the operation-related information, or may be a sensor that detects the operating force of the brake operating member 11 by the driver as the operation-related information. The wheel speed sensor 52 outputs a signal according to the rotation speed of the corresponding wheel 12. The acceleration sensor 53 detects the longitudinal acceleration of the vehicle 10. The motor angle sensor 54 detects the rotation angle of the rotor of the motor generator 40.

[0013] The rotation speed of the wheels 12 based on the detection signal of the wheel speed sensor 52 is referred to as the "wheel speed VW." The acceleration of the vehicle 10 based on the detection signal of the acceleration sensor 53 is referred to as the "longitudinal acceleration GX." The rotation speed of the rotor of the motor generator 40 based on the detection signal of the motor angle sensor 54 is referred to as the "motor rotation speed Nmt."

[0014] <Regenerative Coordination Control Device> The regenerative cooperative control device 100 has a friction braking control unit 60 that controls the friction braking device 30, and a motor control unit 70 that controls the motor generator 40. The multiple control units 60, 70 are configured to be able to transmit and receive information to and from each other. An example of the multiple control units 60, 70 is an electronic control device.

[0015] The friction braking control unit 60 has a processing circuit 61. The processing circuit 61 has a CPU 62 and a memory 63. The memory 63 stores a control program executed by the CPU 62. The processing circuit 61 controls the friction braking device 30 by the CPU 62 executing the control program.

[0016] The motor control unit 70 has a processing circuit 71. The processing circuit 71 has a CPU 72 and a memory 73. The memory 73 stores a control program executed by the CPU 72. The processing circuit 71 controls the motor generator 40 by the CPU 72 executing the control program.

[0017] <Functional configuration of regenerative cooperative control device> The CPU 62 executes the control program in the memory 63, causing the processing circuit 61 to function as a plurality of functional units. The CPU 72 executes the control program in the memory 73, causing the processing circuit 71 to function as a plurality of functional units.

[0018] 2, the multiple functional units include a target deceleration setting unit M11, a regenerative cooperative control unit M13, a start vehicle speed setting unit M15, a switching control unit M17, a correction unit M19, a friction braking control unit M21, a regenerative braking control unit M23, and a drive control unit M25. The processing circuit 61 of the friction braking control unit 60 functions as the target deceleration setting unit M11, the regenerative cooperative control unit M13, the start vehicle speed setting unit M15, the switching control unit M17, and the friction braking control unit M21. The processing circuit 71 of the motor control unit 70 functions as the correction unit M19, the regenerative braking control unit M23, and the drive control unit M25. The drive control unit M25 corresponds to the "braking / driving control unit."

[0019] <Target deceleration setting section> When there is a braking request, the target deceleration setting unit M11 sets a target deceleration DVSTr, which is a target for the deceleration of the vehicle 10. When it detects that the brake operating member 11 is being operated or when there is a deceleration request from another control device, the target deceleration setting unit M11 determines that there is a braking request. For example, when the brake operating member 11 is being operated, the target deceleration setting unit M11 sets the target deceleration DVSTr based on the detection signal of the brake sensor 51.

[0020] <Regenerative Coordination Control Unit> The regenerative cooperative control unit M13 executes a regenerative cooperative process to derive a regenerative braking force command value FxRTr and a frictional braking force command value FxMTr based on the target deceleration DVSTr. The regenerative braking force command value FxRTr is a command value for the regenerative braking force FxR. The frictional braking force command value FxMTr is a command value for the frictional braking force FxM.

[0021] The regenerative cooperation control unit M13 converts the target deceleration DVSTr into a target braking force FxTr. The target braking force FxTr is a target for the braking force Fx of the vehicle 10. In the regenerative cooperation processing, the regenerative cooperation control unit M13 derives a regenerative braking force command value FxRTr and a frictional braking force command value FxMTr so that the sum of the regenerative braking force command value FxRTr and the frictional braking force command value FxMTr is equal to the target braking force FxTr. At this time, it is preferable that the regenerative cooperation control unit M13 derives the regenerative braking force command value FxRTr and the frictional braking force command value FxMTr so that the regenerative braking force command value FxRTr is as large as possible.

[0022] <Start vehicle speed setting section> The start vehicle speed setting unit M15 sets a start vehicle speed VS1Th, which is the vehicle speed when starting the switching control described later. The start vehicle speed setting unit M15 sets the start vehicle speed VS1Th to a smaller vehicle speed as the target deceleration DVSTr is lower. As will be described in detail later, the switching control is a control that is performed just before the vehicle 10 is stopped. Therefore, the start vehicle speed VS1Th is set to, for example, 10 km / h or less.

[0023] For example, the start vehicle speed setting unit M15 sets the start vehicle speed VS1Th using the map shown in FIG. 3. In this case, when the target deceleration DVSTr is less than the first deceleration DVS1, the start vehicle speed setting unit M15 sets the first vehicle speed VS1 as the start vehicle speed VS1Th. When the target deceleration DVSTr is equal to or greater than the second deceleration DVS2, the start vehicle speed setting unit M15 sets the second vehicle speed VS2 as the start vehicle speed VS1Th. The second deceleration DVS2 is greater than the first deceleration DVS1. The second vehicle speed VS2 is greater than the first vehicle speed VS1. When the target deceleration DVSTr is equal to or greater than the first deceleration DVS1 and less than the second deceleration DVS2, the start vehicle speed setting unit M15 sets the start vehicle speed VS1Th to a larger value as the target deceleration DVSTr is greater.

[0024] <Switching control section> Returning to Fig. 2, the switching control unit M17 executes switching control to switch the regenerative braking force FxR to the frictional braking force FxM under a condition in which the regenerative braking force FxR is applied to the vehicle 10. The switching control unit M17 starts the switching control when the vehicle speed VS becomes equal to or lower than the start vehicle speed VS1Th. The vehicle speed VS is a vehicle speed derived based on the motor rotation speed Nmt.

[0025] The switching control includes a main switching control and a preliminary switching control for reducing the rate of decrease of the regenerative braking force FxR compared to when the main switching control is executed. The switching control unit M17 executes the main switching control after executing the preliminary switching control.

[0026] Specifically, when the vehicle speed VS becomes equal to or lower than the start vehicle speed VS1Th, the switching control unit M17 starts the preliminary switching control. In the preliminary switching control, the switching control unit M17 gradually increases the friction braking force command value FxMTr and gradually decreases the regenerative braking force command value FxRTr.

[0027] The process of deriving the multiple command values ​​FxRTr, FxMTr in the preliminary switching control will be described with reference to Fig. 4. Fig. 4 is a map showing the relationship between the vehicle speed VS and the pre-charge frictional braking force FxMp. The pre-charge frictional braking force FxMp indicates the amount of increase in the frictional braking force command value FxMTr during execution of the preliminary switching control.

[0028] In the map shown in FIG. 4, when the vehicle speed VS is greater than the start vehicle speed VS1Th, the pre-charge frictional braking force FxMp is 0 (zero). The switch vehicle speed VS2Th is a vehicle speed smaller than the start vehicle speed VS1Th. As the switch vehicle speed VS2Th, for example, a criterion for determining whether the vehicle 10 is about to stop is set. When the vehicle speed VS is equal to or less than the switch vehicle speed VS2Th, the pre-charge frictional braking force FxMp is maintained at a predetermined braking force FxMp1. When the vehicle speed VS is greater than the switch vehicle speed VS2Th and equal to or less than the start vehicle speed VS1Th, the pre-charge frictional braking force FxMp becomes larger as the vehicle speed VS becomes smaller.

[0029] When the friction braking force FxM is increased from 0 (zero), a response delay of the friction braking force FxM is likely to occur in the initial period of increase. Therefore, a friction braking force that serves as a criterion for determining whether a response delay is likely to occur or not is set as a predetermined braking force FxMp1. The braking force range in which a response delay of the friction braking force FxM occurs is determined by the specifications of the friction braking device 30 and the friction brake 20, etc.

[0030] When the start vehicle speed VS1Th is set by the start vehicle speed setting unit M15, the switching control unit M17 creates a map as shown in FIG. 4. The switching vehicle speed VS2Th is a preset vehicle speed, and the predetermined braking force FxMp1 is a preset magnitude. Therefore, the switching control unit M17 sets the gradient of the map line Lmap shown in FIG. 4 during the period from the start vehicle speed VS1Th to the switching vehicle speed VS2Th according to the start vehicle speed VS1Th. The gradient of the map line Lmap is the increase amount of the pre-charge friction braking force FxMp with respect to the decrease in the vehicle speed VS. This allows the switching control unit M17 to create the map. The switching control unit M17 updates the map every time the start vehicle speed VS1Th is updated. However, when the switching control unit M17 starts the switching control because the vehicle speed VS becomes equal to or lower than the start vehicle speed VS1Th, the switching control unit M17 stops updating the map.

[0031] In the preliminary switching control, the switching control unit M17 acquires the precharge friction braking force FxMp corresponding to the vehicle speed VS from the map shown in Fig. 4. Then, the switching control unit M17 derives a value obtained by subtracting the precharge friction braking force FxMp from the regenerative braking force command value FxRTr as the latest value of the regenerative braking force command value FxRTr. Also, the switching control unit M17 derives a value obtained by subtracting the latest value of the regenerative braking force command value FxRTr from the target braking force FxTr as the latest value of the friction braking force command value FxMTr.

[0032] When the vehicle speed VS becomes equal to or lower than the switching vehicle speed VS2Th during execution of the preliminary switching control, the switching control unit M17 ends the preliminary switching control and starts the main switching control. In the main switching control, the switching control unit M17 derives the regenerative braking force command value FxRTr and the friction braking force command value FxMTr so as to satisfy the following conditions (A1) and (A2).

[0033] (A1) When the vehicle speed VS becomes 0 (zero), the regenerative braking force command value FxRTr becomes 0 (zero). (A2) Decreasing the regenerative braking force command value FxRTr at a constant gradient while increasing the frictional braking force command value FxMTr at the same gradient.

[0034] <Correction section> Returning to FIG. 2, when switching control is being executed, the correction unit M19 executes a correction process to correct the braking force with the higher response speed, out of the regenerative braking force FxR and the frictional braking force FxM, so that the magnitude of the difference ΔDVS between the deceleration DVS of the vehicle 10 and the target deceleration DVSTr becomes smaller.

[0035] Here, the friction braking device 30 is a hydraulic braking device that applies a friction braking force FxM to the vehicle 10 by increasing the hydraulic pressure in the wheel cylinder 21. Therefore, particularly during low braking, the response speed of the friction braking force FxM is slower than the response speed of the regenerative braking force FxR.

[0036] Therefore, in the correction process, the correction unit M19 corrects the regenerative braking force command value FxRTr in accordance with the difference ΔDVS, out of the regenerative braking force command value FxRTr and the frictional braking force command value FxMTr derived by the switching control unit M17. For example, the correction unit M19 corrects the regenerative braking force command value FxRTr by feedback control using the difference ΔDVS as an input.

[0037] The correction unit M19 starts the correction process when the switching control is started, and ends the correction process immediately before the regenerative braking force FxR becomes 0 (zero). As described above, the switching control includes the preliminary switching control and the main switching control. Therefore, it is preferable that the correction unit M19 ends the correction process when the control switches from the preliminary switching control to the main switching control.

[0038] <Friction braking control unit> The friction braking control unit M21 controls the friction braking device 30. Specifically, the friction braking control unit M21 adjusts the friction braking force FxM by operating the friction braking device 30 based on the friction braking force command value FxMTr.

[0039] <Regenerative braking control unit> The regenerative braking control unit M23 controls the regenerative braking force FxR by making the motor generator 40 function as a generator. Specifically, the regenerative braking control unit M23 controls the inverter of the motor generator 40 so that the amount of power generated by the motor generator 40 increases as the regenerative braking force command value FxRTr increases. In this way, the regenerative braking control unit M23 adjusts the regenerative braking force FxR according to the regenerative braking force command value FxRTr.

[0040] <Drive control unit> When the vehicle 10 is stopped, the drive control unit M25 controls the drive force Fd by making the motor generator 40 function as an electric motor. For example, when the vehicle 10 is stopped on a downhill road, the drive control unit M25 operates the motor generator 40 so that a drive force Fd in the backward direction is applied to the wheels 12. When the vehicle 10 is stopped on an uphill road, the drive control unit M25 operates the motor generator 40 so that a drive force Fd in the forward direction is applied to the wheels 12. When the road surface on which the vehicle 10 is stopped is not a slope, the drive control unit M25 controls the motor generator 40 so that the drive force Fd becomes 0 (zero).

[0041] However, the operating force of the brake operating member 11 by the driver may be reduced after the vehicle 10 is stopped. In this case, the drive control unit M25 operates the motor generator 40 so that a driving force Fd corresponding to the creep torque is applied to the wheels 12.

[0042] <Braking process> The braking process, which is a flow of processing in the regeneration coordination control device 100 when adjusting the braking force Fx of the vehicle, will be described with reference to Fig. 5. The braking process is repeatedly executed at every predetermined control cycle. However, when the execution condition of the switching control is satisfied, the execution of the braking process is stopped.

[0043] In step S11, the regenerative cooperation control device 100 determines whether or not there is a braking request. In this embodiment, the processing of step S11 is executed by the processing circuit 61 of the friction braking control unit 60 functioning as the target deceleration setting section M11. If the regenerative cooperation control device 100 determines that there is a braking request (S11: YES), the processing proceeds to step S13. On the other hand, if the regenerative cooperation control device 100 determines that there is no braking request (S11: NO), the regenerative cooperation control device 100 temporarily ends the braking processing.

[0044] In step S13, the regenerative coordination control device 100 sets a target deceleration DVSTr. In this embodiment, the processing circuit 61 of the friction braking control unit 60 functions as a target deceleration setting section M11, thereby executing the processing of step S13.

[0045] In the following step S15, the regenerative coordination control device 100 converts the target deceleration DVSTr into a target braking force FxTr. In the next step S17, the regenerative cooperation control device 100 derives the smaller of the value obtained by subtracting the frictional braking force command value FxMTr from the target braking force FxTr and the regenerative braking force upper limit value FxRmax as the regenerative braking force command value FxRTr. The regenerative braking force upper limit value FxRmax is the maximum value of the regenerative braking force FxR that the motor generator 40 can apply to the vehicle 10. In the following step S19, the regenerative cooperation control device 100 derives the larger of 0 (zero) and the value obtained by subtracting the regenerative braking force command value FxRTr from the target braking force FxTr as the frictional braking force command value FxMTr. In this embodiment, the processing circuit 61 of the frictional braking control unit 60 functions as the regenerative cooperation control unit M13, thereby executing the processing of steps S17 and S19.

[0046] In step S21, the regenerative cooperative control device 100 operates the motor generator 40 based on the regenerative braking force command value FxRTr, and operates the friction braking device 30 based on the friction braking force command value FxMTr. In this embodiment, the processing circuit 71 of the motor control unit 70 functions as a regenerative braking control unit M23, thereby executing the process of controlling the motor generator 40 in the process of step S21. The processing circuit 61 of the friction braking control unit 60 functions as a friction braking control unit M21, thereby executing the process of controlling the friction braking device 30 in the process of step S21.

[0047] In step S23, the regenerative cooperative control device 100 sets a vehicle speed corresponding to the target deceleration DVSTr as the start vehicle speed VS1Th by using, for example, the map shown in Fig. 3. In this embodiment, the processing circuit 61 of the friction braking control unit 60 functions as the start vehicle speed setting section M15 to execute the processing of step S23.

[0048] In the next step S25, the regeneration cooperation control device 100 judges whether the vehicle speed VS is equal to or lower than the start vehicle speed VS1Th. If the vehicle speed VS is equal to or lower than the start vehicle speed VS1Th (S25: YES), the regeneration cooperation control device 100 judges that the execution condition for the switching control is satisfied, and ends the braking process.

[0049] On the other hand, when the vehicle speed VS is greater than the start vehicle speed VS1Th (S25: NO), the regeneration cooperation control device 100 determines that the execution condition for the switching control is not satisfied and temporarily ends the braking process. In this case, the regeneration cooperation control device 100 continues to repeatedly execute the braking process.

[0050] <Processing during switching> 6, a description will be given of a switching process, which is a process flow in the regeneration coordination control device 100 when the switching control is executed. The switching process is repeatedly executed for each predetermined control cycle when the vehicle 10 has not yet stopped and the execution condition for the switching control is satisfied.

[0051] In step S43, the regeneration cooperation control device 100 judges whether the vehicle speed VS is greater than the switch vehicle speed VS2Th. If the regeneration cooperation control device 100 judges that the vehicle speed VS is greater than the switch vehicle speed VS2Th (S43: YES), the regeneration cooperation control device 100 executes the preliminary switching control. On the other hand, if the regeneration cooperation control device 100 judges that the vehicle speed VS is equal to or less than the switch vehicle speed VS2Th (S43: NO), the regeneration cooperation control device 100 executes the main switching control.

[0052] The flow of processing of the preliminary switching control will be described. In the first step S45, the regenerative cooperation control device 100 sets a braking force corresponding to the vehicle speed VS as the pre-charge friction braking force FxMp by using a map as shown in FIG. 4. In the next step S47, the regenerative cooperation control device 100 derives the smaller of a value obtained by subtracting the pre-charge friction braking force FxMp from the target braking force FxTr and a regenerative braking force upper limit value FxRmax as the regenerative braking force command value FxRTr. In the next step S49, the regenerative cooperation control device 100 derives a value obtained by subtracting the regenerative braking force command value FxRTr from the target braking force FxTr as the friction braking force command value FxMTr. In this embodiment, the processing circuit 61 of the friction braking control unit 60 functions as the switching control unit M17, thereby executing the processing of steps S45 to S49.

[0053] In the next step S51, the regeneration coordination control device 100 derives a difference ΔDVS between the target deceleration DVSTr and the deceleration DVS by subtracting the deceleration DVS of the vehicle 10 from the target deceleration DVSTr. In the following step S53, the regeneration coordination control device 100 executes a correction process to correct the regenerative braking force command value FxRTr so that the magnitude of the difference ΔDVS becomes smaller. In this embodiment, the processing circuit 71 of the motor control unit 70 functions as the correction section M19 to execute the processes of steps S51 and S53. Thereafter, the regeneration coordination control device 100 proceeds to step S59.

[0054] The flow of the process of this switching control will be described. In the first step S55, the regenerative cooperation control device 100 derives a value obtained by subtracting the switching braking force ΔFx2 from the regenerative braking force command value FxRTr as the regenerative braking force command value FxRTr. The switching braking force ΔFx2 is set to a magnitude that satisfies the above conditions (A1) and (A2). In the next step S57, the regenerative cooperation control device 100 derives a value obtained by subtracting the regenerative braking force command value FxRTr from the target braking force FxTr as the friction braking force command value FxMTr. In this embodiment, the processing circuit 61 of the friction braking control unit 60 functions as the switching control unit M17, thereby executing the processes of steps S55 and S57. Thereafter, the regenerative cooperation control device 100 proceeds to step S59.

[0055] In step S59, the regenerative coordination controller 100 operates the motor generator 40 based on the regenerative braking force command value FxRTr, and operates the friction braking device 30 based on the friction braking force command value FxMTr. In this embodiment, the processing circuit 71 of the motor control unit 70 functions as the regenerative braking control unit M23, thereby executing the process of controlling the motor generator 40 among the processes of step S59. The processing circuit 61 of the friction braking control unit 60 functions as the friction braking control unit M21, thereby executing the process of controlling the friction braking device 30 among the processes of step S59. Then, the regenerative coordination controller 100 temporarily ends the switching process.

[0056] <Post-shutdown processing> 7, a post-stop process which is a flow of processes performed by the regeneration coordination control device 100 while the vehicle 10 is stopped will be described. The post-stop process is repeatedly executed for each predetermined control cycle.

[0057] In step S81, the regenerative cooperation control device 100 determines whether the vehicle 10 is stopped. If the regenerative cooperation control device 100 determines that the vehicle 10 is stopped (S81: YES), the process proceeds to step S83. On the other hand, if the regenerative cooperation control device 100 determines that the vehicle 10 is not stopped (S81: NO), the regenerative cooperation control device 100 temporarily ends the post-stop process.

[0058] In step S83, the regenerative cooperation control device 100 judges whether the target braking force FxTr is equal to or less than the start judgment braking force FxA. When starting the vehicle 10, the driver cancels the operation of the brake operating member 11. The target braking force FxTr is a value based on at least one of the operation amount and the operation force of the brake operating member 11. Therefore, the start judgment braking force FxA is set as a criterion for judging whether the driver intends to start the vehicle 10. If the target braking force FxTr is equal to or less than the start judgment braking force FxA (S83: YES), the regenerative cooperation control device 100 shifts the process to step S85. On the other hand, if the target braking force FxTr is greater than the start judgment braking force FxA (S83: NO), the regenerative cooperation control device 100 shifts the process to step S87.

[0059] In step S85, the regenerative cooperation control device 100 sets the creep driving force Fc as the driving force Fd. The creep driving force Fc is a driving force equivalent to the creep torque. Then, the regenerative cooperation control device 100 proceeds to step S97.

[0060] In step S87, the regeneration coordination controller 100 acquires hill road information about the road surface on which the vehicle 10 stops. Specifically, the regeneration coordination controller 100 acquires the road surface gradient. For example, the regeneration coordination controller 100 can estimate the road surface gradient based on the longitudinal acceleration GX.

[0061] In the next step S89, the regenerative cooperation control device 100 judges whether the road surface on which the vehicle 10 is stopped is a downhill road. If the regenerative cooperation control device 100 judges that the road surface is a downhill road (S89: YES), the process proceeds to step S91. On the other hand, if the regenerative cooperation control device 100 judges that the road surface is not a downhill road (S89: NO), the process proceeds to step S93.

[0062] In step S91, the regenerative cooperation controller 100 sets a driving force in the backward direction as the driving force Fd. Then, the regenerative cooperation controller 100 shifts the process to step S97.

[0063] In step S93, the regenerative coordination control device 100 determines whether the road surface on which the vehicle 10 is stopped is an uphill road. If the regenerative coordination control device 100 determines that the road surface is an uphill road (S93: YES), the process proceeds to step S95. On the other hand, if the regenerative coordination control device 100 determines that the road surface is not an uphill road (S89: NO), the road surface can be considered to be a level road, and therefore the post-stop process is temporarily terminated. In this case, the regenerative coordination control device 100 does not cause the motor generator 40 to apply the driving force Fd to the wheels 12.

[0064] In step S95, the regenerative cooperation controller 100 sets a driving force in the forward direction as the driving force Fd. Then, the regenerative cooperation controller 100 shifts the process to step S97.

[0065] In step S97, the regeneration coordination controller 100 drives the motor generator 40 so that the set driving force Fd is applied to the wheels 12. Thereafter, the regeneration coordination controller 100 temporarily ends the post-stop process.

[0066] In this embodiment, the processing circuit 71 of the motor control unit 70 functions as the drive control section M25 to execute the processes of steps S85 to S97. <Actions and Effects of the Present Embodiment> The operation and effects of this embodiment will be described with reference to FIG.

[0067] At a timing t11 while the vehicle 10 is traveling, a braking request is generated, for example, when the driver starts to operate the brake operating member 11. Then, as shown in (B) of Fig. 8, the target deceleration DVSTr gradually increases. Therefore, a braking force Fx is applied to the vehicle 10 through the execution of the braking process.

[0068] That is, when the target braking force FxTr correlated with the target deceleration DVSTr is equal to or smaller than the regenerative braking force upper limit value FxRmax, a value equal to the target braking force FxTr is derived as the regenerative braking force command value FxRTr, as shown in Fig. 8(C).The motor generator 40 is operated based on the regenerative braking force command value FxRTr.On the other hand, 0 (zero) is derived as the frictional braking force command value FxMTr.

[0069] After timing t12, the target deceleration DVSTr and the target braking force FxTr are maintained as shown in Fig. 8(B). Therefore, after timing t12, the start vehicle speed VS1Th is maintained at a vehicle speed according to the target braking force FxTr at timing t12.

[0070] When the regenerative braking force FxR is applied to the vehicle 10 in this manner, the vehicle speed VS gradually decreases as shown in Fig. 8(A). Then, at timing t13, the vehicle speed VS reaches the start vehicle speed VS1Th, and the switching control is started from timing t13.

[0071] From timing t13, preliminary switching control is started as the switching control. In the preliminary switching control, the rate of decrease of the regenerative braking force command value FxRTr and the rate of increase of the frictional braking force command value FxMTr are relatively small.

[0072] As described above, the frictional braking force FxM is increased by supplying brake fluid to the wheel cylinder 21. Therefore, the response speed of the frictional braking force FxM is slower than that of the regenerative braking force FxR. In particular, at the initial stage of generating hydraulic pressure in the wheel cylinder 21, the frictional braking force FxM is likely to deviate from the frictional braking force command value FxMTr. When the frictional braking force FxM deviates from the frictional braking force command value FxMTr, the deceleration DVS of the vehicle 10 deviates from the target deceleration DVSTr.

[0073] Therefore, in the regeneration cooperation control device 100, when the preliminary switching control is executed, a correction process is executed to correct the regenerative braking force command value FxRTr so that the magnitude of the difference ΔDVS between the target deceleration DVSTr and the deceleration DVS of the vehicle 10 is reduced. Then, the friction braking device 30 is operated based on the friction braking force command value FxMTr derived by the preliminary switching control, and the motor generator 40 is operated based on the regenerative braking force command value FxRTr corrected by the correction process. As a result, the response delay of the friction braking force FxM is compensated for by the regenerative braking force FxR. This suppresses the sum of the friction braking force FxM and the regenerative braking force FxR from deviating from the target braking force FxTr. Therefore, the regeneration cooperation control device 100 can suppress the deceleration of the vehicle 10 from fluctuating due to the execution of the switching control.

[0074] The vehicle speed VS decreases even while the preliminary switching control is being executed. Then, at timing t14, the vehicle speed VS reaches the switching vehicle speed VS2Th. In this case, it can be determined that the vehicle 10 is about to stop, and therefore the control is switched from the preliminary switching control to the main switching control.

[0075] In this switching control, the rate of decrease of the regenerative braking force command value FxRTr and the rate of increase of the frictional braking force command value FxMTr become faster than when the preliminary switching control is executed. Then, at timing t15 when the vehicle speed VS becomes 0 (zero), the regenerative braking force command value FxRTr becomes 0 (zero). That is, the switching from the regenerative braking force FxR to the frictional braking force FxM is completed.

[0076] Generally, when the vehicle speed VS approaches 0 (zero), the controllability of the regenerative braking force FxR decreases. If the correction process is executed even when the controllability of the regenerative braking force FxR decreases, the execution of the correction process may cause the fluctuation of the deceleration DVS of the vehicle 10 to increase.

[0077] In this embodiment, when the switching control is started, the above correction process is terminated. That is, in the regenerative cooperative control device 100, when the switching control is started, the correction process is started, and the correction process is terminated immediately before the regenerative braking force FxR becomes 0 (zero). Therefore, the regenerative cooperative control device 100 can suppress fluctuations in the deceleration DVS immediately before the vehicle 10 stops.

[0078] As described above, at the start of the switching control, a braking force equal to the predetermined braking force FxMp1 is set as the frictional braking force command value FxMTr. Therefore, a response delay of the frictional braking force FxM is unlikely to occur during the switching control.

[0079] In this embodiment, the following effects can be further obtained. (1) When the frictional braking force command value FxMTr is significantly lower than the predetermined braking force FxMp1 at the start of the main switching control, the deceleration DVS may fluctuate due to a response delay of the frictional braking force FxM during the execution of the main switching control. On the other hand, when the frictional braking force command value FxMTr is significantly higher than the predetermined braking force FxMp1 at the start of the main switching control, the execution time of the preliminary switching control may become too long, and the efficiency of recovery of regenerative energy may decrease.

[0080] Therefore, in the regeneration cooperation control device 100, the lower the target deceleration DVSTr, the smaller the vehicle speed VS1Th is set as the starting vehicle speed. This allows the start timing of the preliminary switching control to be changed according to the target deceleration DVSTr. As a result, the friction braking force command value FxMTr is prevented from falling significantly below the predetermined braking force FxMp1 at the start of the main switching control. In addition, when the target deceleration DVSTr is low, the preliminary switching control is prevented from being started too early. Therefore, the regeneration cooperation control device 100 can suppress the fluctuation of the deceleration DVS during the execution of the main switching control while suppressing the decrease in the recovery efficiency of the regenerative energy during vehicle braking.

[0081] (2) Consider a case where the creep driving force Fc continues to be applied as the driving force Fd to the wheels 12 of the vehicle 10 after the vehicle 10 has stopped. In this case, the driving force Fd continues to be applied to the wheels 12 even though the driver has no intention of starting the vehicle 10, so it is difficult to say that the energy efficiency of the vehicle 10 is high.

[0082] In this regard, when the regenerative cooperative control device 100 determines that the vehicle 10 is not stopped on a slope, the driving force Fd is not applied to the vehicle 10. This allows the regenerative cooperative control device 100 to suppress unnecessary consumption of electric energy while the vehicle 10 is stopped.

[0083] However, when it is determined that the vehicle 10 is stopped on a downhill road, a driving force in the reverse direction is applied to the wheels 12 as a driving force Fd, as shown in Fig. 8(D). When the vehicle 10 is stopped on a downhill road, the driving force in the reverse direction acts on the vehicle 10 as a force that prevents the vehicle 10 from rolling down due to its own weight. In other words, when the vehicle 10 is stopped on a downhill road, the regenerative cooperative control device 100 applies a driving force in the reverse direction to the wheels 12, thereby preventing the vehicle 10 from rolling down due to its own weight.

[0084] Furthermore, when it is determined that the vehicle 10 is stopped on an uphill road, a driving force in the forward direction is applied to the wheels 12 as driving force Fd. When the vehicle 10 is stopped on an uphill road, the driving force in the forward / reverse direction acts on the vehicle 10 as a force that prevents the vehicle 10 from rolling down due to its own weight. In other words, when the vehicle 10 is stopped on an uphill road, the regenerative cooperative control device 100 can prevent the vehicle 10 from rolling down due to its own weight by applying a driving force in the forward / reverse direction to the wheels 12.

[0085] However, if the target braking force FxTr becomes equal to or less than the start determination braking force FxA while the vehicle 10 is stopped, it is assumed that the driver intends to start the vehicle 10. Therefore, when the target braking force FxTr becomes equal to or less than the start determination braking force FxA, the creep driving force Fc is applied to the wheels 12 as the driving force Fd. This allows the regenerative cooperative control device 100 to contribute to the prompt start of creep running of the vehicle 10 when the driver cancels the braking operation.

[0086] <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0087] If the regenerative cooperative control device applies a driving force in the backward direction to the wheels 12 when the vehicle 10 is stopped on a downhill road, then it is not necessary for the regenerative cooperative control device to apply a driving force in the forward direction to the wheels 12 when the vehicle 10 is stopped on an uphill road. Conversely, if the regenerative cooperative control device applies a driving force in the forward direction to the wheels 12 when the vehicle 10 is stopped on an uphill road, then it is not necessary for the regenerative cooperative control device to apply a driving force in the backward direction to the wheels 12 when the vehicle 10 is stopped on a downhill road.

[0088] The regenerative cooperative control device does not have to apply the driving force Fd to the wheels 12 even if the target braking force FxTr is equal to or less than the start-determining braking force FxA while the vehicle 10 is stopped. It is not essential to vary the start vehicle speed VS1Th according to the target deceleration DVSTr. For example, the start vehicle speed VS1Th may be a vehicle speed higher than the switch vehicle speed VS2Th and a predetermined vehicle speed that has been set in advance. Even in this case, when the vehicle speed VS becomes equal to or lower than the switch vehicle speed VS2Th, the control switches from the preliminary switching control to the main switching control. Therefore, when the start vehicle speed VS1Th is fixed at a predetermined vehicle speed, it is preferable to make the rate of reduction of the regenerative braking force FxR smaller as the target deceleration DVSTr at the start of the preliminary switching control becomes smaller.

[0089] The switching control does not have to include preliminary switching control as long as it includes the main switching control. In this case, the regenerative cooperative control device starts the main switching control when the vehicle speed VS becomes equal to or lower than the start vehicle speed. In addition, the regenerative cooperative control device corrects the regenerative braking force command value FxRTr derived by the main switching control through a correction process so that the difference ΔDVS between the target deceleration DVSTr and the deceleration DVS becomes smaller. However, it is preferable that the regenerative cooperative control device terminates the correction process during the execution of the main switching control.

[0090] In the above embodiment, the correction process is terminated when the control is switched from the preliminary switching control to the main switching control. However, if the correction process is terminated immediately before the vehicle speed VS becomes 0 (zero), the correction process may be terminated while the main switching control is being executed. However, when the correction process is executed even while the main switching control is being executed, it is preferable to make the gain of the feedback control smaller compared to when the preliminary switching control is being executed.

[0091] The friction braking device may be an electric braking device capable of applying a friction braking force corresponding to the rotation angle of the electric motor to the wheels 12. When such an electric braking device is employed as the friction braking device, the friction braking force FxM may have a higher response speed than the regenerative braking force FxR. When the friction braking force FxM has a higher response speed than the regenerative braking force FxR, the correction process may correct the friction braking force command value FxMTr so that the difference ΔDVS between the target deceleration DVSTr and the deceleration DVS becomes smaller. On the other hand, when the friction braking force FxM has a lower response speed than the regenerative braking force FxR, the correction process may correct the regenerative braking force command value FxRTr so that the difference ΔDVS becomes smaller.

[0092] The braking force to be corrected by the correction process is defined as the braking force to be corrected. In the above embodiment, the braking force with the higher response speed out of the regenerative braking force and the frictional braking force is defined as the braking force to be corrected, but this is not limited to this. For example, the braking force to be corrected may be determined based on the control accuracy and the amount of data used. For example, the braking force to be corrected out of the regenerative braking force and the frictional braking force, whichever has the higher control accuracy, may be defined as the braking force to be corrected, or the braking force with the lower amount of data used may be defined as the braking force to be corrected.

[0093] The multiple processing circuits 61, 71 may be configured as circuits including one or more processors operating according to a computer program, one or more dedicated hardware circuits such as dedicated hardware for performing at least some of the various processes, or a combination of these. An example of dedicated hardware is an application specific integrated circuit (ASIC). The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to perform processes. The memory, i.e., storage medium, includes any available medium accessible by a general purpose or dedicated computer.

[0094] <Other technical ideas> Next, the technical ideas that can be understood from the above embodiment and modified examples will be described. [Additional Note 1] The switching control includes a main switching control and a preliminary switching control that reduces a reduction rate of the regenerative braking force compared to when the main switching control is executed, The switching control unit is When the vehicle speed becomes equal to or lower than the start vehicle speed, the preliminary switching control is started. It is preferable that, when the vehicle speed becomes equal to or lower than a switching vehicle speed which is lower than the starting vehicle speed, the preliminary switching control is terminated and the main switching control is started.

[0095] [Additional Note 2] In the switching control, it is preferable that the switching control unit reduces the regenerative braking force so that the regenerative braking force becomes 0 (zero) when the vehicle speed becomes 0 (zero).

[0096] The term "at least one" used herein means "one or more" of the desired options. As an example, the term "at least one" used herein means "only one option" or "both of two options" if the number of options is two. As another example, the term "at least one" used herein means "only one option" or "any combination of two or more options" if the number of options is three or more. [Explanation of symbols]

[0097] 10…Vehicle 12...Wheel 20...Friction brake 21...Wheel cylinder 30...Friction braking device (an example of a hydraulic braking device) 40...Motor generator (an example of a regenerative braking device, an example of a braking / driving device) 60...Friction braking control unit 70...Motor control unit 100...Regenerative cooperative control device M11…Target deceleration setting section M13…Regenerative coordination control unit M15…Start vehicle speed setting section M17…Switching control section M19…Correction part M21: Friction braking control section M23…Regenerative braking control unit M25: Drive control unit (braking / driving control unit)

Claims

1. A regenerative cooperative control device applied to a vehicle including a regenerative braking device that applies a regenerative braking force to the vehicle and a friction braking device that applies a friction braking force to the vehicle, a switching control unit that executes switching control to switch the regenerative braking force to the frictional braking force under a condition in which the regenerative braking force is applied to the vehicle; a correction unit that executes a correction process to correct the braking force having a high response speed out of the regenerative braking force and the frictional braking force when the switching control is being executed so that a magnitude of a difference between a deceleration of the vehicle and a target deceleration becomes small. Regenerative cooperative control device.

2. The vehicle has, as the friction braking device, a hydraulic braking device that applies the friction braking force by increasing a hydraulic pressure in a wheel cylinder, The correction unit corrects the regenerative braking force in the correction process so that a magnitude of a difference between the deceleration of the vehicle and the target deceleration becomes smaller. The regenerative coordination control device according to claim 1 .

3. The correction unit starts the correction process when the switching control is started, and ends the correction process immediately before the regenerative braking force becomes 0 (zero). The regenerative coordination control device according to claim 1 .

4. a start vehicle speed setting unit that sets a start vehicle speed of the switching control to a smaller vehicle speed as the target deceleration decreases; The switching control unit starts the switching control when the vehicle speed becomes equal to or lower than the start vehicle speed. The regenerative cooperative control device according to any one of claims 1 to 3.

5. The regenerative braking device is a braking / driving device capable of applying one of a regenerative braking force or a driving force to a wheel of the vehicle, A braking / driving control unit is provided that controls the braking / driving device so that the driving force for rotating the wheels in a backward direction is applied to the wheels when the vehicle stops on a downhill road. The regenerative coordination control device according to claim 1 .

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