Regenerative cooperation control device and regenerative cooperation control method

Abstract

A regenerative cooperation control device comprises a transition control device (M17) designed to perform transition control for a transition from a regenerative braking force to a friction braking force in a situation where the regenerative braking force is applied to a vehicle, and a correction device (M19) designed to perform a correction process that corrects a difference between the regenerative braking force and the friction braking force, which has a higher reaction rate, such that the magnitude of a difference between a deceleration of the vehicle and a target deceleration during an execution of the transition control.

Description

Technical field

[0001] The present disclosure relates to a regenerative cooperation control device and a regenerative cooperation control method. State of the art

[0002] Patent literature 1 discloses a regenerative cooperation control device that controls a regenerative braking force and a friction braking force applied to a vehicle. When the vehicle speed becomes less than or equal to a predetermined vehicle speed in a situation where the regenerative braking force is applied, the regenerative cooperation control device performs a transition control. During this control, the regenerative braking force is gradually reduced and the friction braking force is gradually increased. Citation list for patent literature

[0003] Patent literature 1: WO 2010 / 128652 A Brief description of the invention: Technical problem

[0004] Regenerative braking force and friction braking force have different reaction rates. Consequently, during the execution of a transition control, the sum of the actual values ​​of the regenerative braking force and the friction braking force can fluctuate, causing a fluctuation in vehicle deceleration. Solution to the problem

[0005] A regenerative cooperation control device according to one aspect of the present disclosure is used in a vehicle. The vehicle comprises a regenerative braking device designed to apply a regenerative braking force and a friction braking device designed to apply a friction braking force.The regenerative cooperation control device comprises a transition control device designed to perform a transition control for a transition from the regenerative braking force to the friction braking force in a situation where the regenerative braking force is applied to the vehicle, and a correction device designed to perform a correction process that corrects a difference between the regenerative braking force and the friction braking force, which has a higher reaction rate, such that the magnitude of a difference between a deceleration of the vehicle and a target deceleration is reduced during an execution of the transition control.

[0006] A regenerative cooperation control method according to another aspect of the present disclosure is employed in a vehicle. The vehicle comprises a regenerative braking device configured to apply a regenerative braking force and a friction braking device configured to apply a friction braking force. The regenerative cooperation control method comprises executing a transition control for a transition from the regenerative braking force to the friction braking force in a situation where the regenerative braking force is applied to the vehicle, and executing a correction process that corrects for a higher reaction rate between the regenerative braking force and the friction braking force, such that the magnitude of the difference between the vehicle's deceleration and a target deceleration decreases during the execution of the transition control. Brief description of drawings [ Fig. 1] Fig. Figure 1 is a diagram schematically showing a vehicle comprising a regenerative cooperation control device according to one embodiment. [ Fig. 2] Fig. Figure 2 is a block diagram illustrating a functional design of the regenerative cooperation control device, which is located in Fig. 1 is shown. [ Fig. 3] Fig. 3 is a characteristic map that is defined by the regenerative cooperation control device, which is in Fig. Figure 1 is used to represent the relationship between the target deceleration and the starting vehicle speed for a transition control system. [ Fig. 4] Fig. 4 is a characteristic map that is defined by the regenerative cooperation control device, which is in Fig. Figure 1 is used to determine the amount by which the friction brake force command value is increased during the execution of a preliminary transition control. [ Fig. 5] Fig. Figure 5 is a flowchart illustrating the processing flow at the regenerative cooperation control device located in Fig. Figure 1 shows what happens when a braking force is applied to the vehicle. [ Fig. 6] Fig. 6 is a flowchart that illustrates the processing flow in the Fig. The regenerative cooperation control device shown in 1 represents the following when a transition control is executed. [ Fig. 7] Fig. 7 is a flowchart that illustrates the processing flow in the Fig. 1 represents the regenerative cooperation control device when the vehicle is in a stopped state. [ Fig. 8] Fig. 8 is a timeline depicting a case where the in Fig. 1. The vehicle shown is stopped by applying a braking force. Description of embodiments

[0007] An embodiment of a regenerative cooperation control device and a regenerative cooperation control method is now described with reference to Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. 8 described.

[0008] Fig. Figure 1 represents a vehicle 10 comprising a regenerative cooperation control device 100. The vehicle 10 includes a brake actuation element 11, wheels 12, friction brakes 20, a friction brake device 30, a motor generator 40, and sensors. The brake actuation element 11 is actuated by a driver to decelerate the vehicle 10. The brake actuation element 11 is, for example, a brake pedal. Fig. 1 represents only one of the wheels 12 and one of the friction brakes 20. <reibungsbremse>

[0009] The friction brakes 20 each operate to apply a frictional braking force to the corresponding wheel 12. The friction brake 20 comprises a wheel cylinder 21, a rotating element 22, and friction elements 23. The rotating element 22 rotates in unison with the wheel 12. Accordingly, a frictional braking force is applied to the wheel 12 by pressing the friction elements 23 against the rotating element 22. As the fluid pressure in the wheel cylinder 21 increases, the force exerted by pressing the friction element 23 against the rotating element 22 also increases. This allows the friction brake 20 to apply a greater frictional braking force to the wheel 12 as the hydraulic pressure in the wheel cylinder 21 increases. <reibungsbremsvorrichtung>

[0010] The friction braking device 30 comprises a delivery source 31 that dispenses a brake fluid. Examples of the delivery source 31 include an electric pump and an electric cylinder. When the brake fluid dispensed by the delivery source 31 is supplied to the wheel cylinder 21, a friction braking force is applied to the wheel 12. <motorgenerator>

[0011] The motor-generator 40 is a power source for the vehicle 10. When the motor-generator 40 acts as an electric motor, a driving force is applied to the wheel 12. The driving force in the direction of rotation of the wheel 12, which is applied when the vehicle 10 is moved forward, is referred to as the "forward driving force." The driving force in the direction of rotation of the wheel 12, which is applied when the vehicle 10 is moved backward, is referred to as the "reverse driving force." The motor-generator 40 can also act as a power generator. In this case, a regenerative braking force, corresponding to the amount of electrical power generated by the motor-generator 40, is applied to the vehicle 10.This means that the motor-generator 40 acts as a regenerative braking device, applying a regenerative braking force to the vehicle 10, and as a drive device designed to apply a driving force to the wheels 12 of the vehicle 10. The motor-generator 40 corresponds to a “braking / driving device”. <sensor>

[0012] The sensors output detection signals corresponding to detection results to the regenerative cooperation control device 100. The sensors include a brake sensor 51, wheel speed sensors 52, an acceleration sensor 53, and an engine angle sensor 54. The brake sensor 51 detects actuation-related information regarding the driver's actuation of the brake actuator 11. The brake sensor 51 can be a stroke sensor that detects the amount by which the driver actuates the brake actuator 11 as the actuation-related information. Alternatively, the brake sensor 51 can be a sensor that detects the force exerted by the driver actuating the brake actuator 11 as the actuation-related information. Each wheel speed sensor 52 outputs a signal corresponding to the rotational speed of the respective wheel 12. The acceleration sensor 53 detects the longitudinal acceleration of the vehicle 10.The motor angle sensor 54 detects the rotation angle of a rotor of the motor generator 40.

[0013] The rotational speed of wheel 12, based on a detection signal from the wheel speed sensor 52, is referred to as the "wheel speed VW". The acceleration of vehicle 10, based on a detection signal from the acceleration sensor 53, is referred to as the "longitudinal acceleration GX". The rotational speed of the rotor of the motor-generator 40, based on a detection signal from the motor angle sensor 54, is referred to as the "motor rotational speed Nmt". <regenerativkooperationssteuervorrichtung>

[0014] The regenerative cooperation control device 100 comprises a friction brake control unit 60, which controls the friction brake device 30, and a motor control unit 70, which controls the motor generator 40. The control units 60 and 70 are designed to send and receive information to and from each other. Examples of the control units 60 and 70 include an electronic control unit.

[0015] The friction brake control unit 60 comprises a processing circuit 61. The processing circuit 61 includes a CPU 62 and a memory 63. The memory 63 stores a control program that is executed by the CPU 62. When the CPU 62 executes the control program, the processing circuit 61 controls the friction brake device 30.

[0016] The motor control unit 70 comprises a processing circuit 71. The processing circuit 71 includes a CPU 72 and a memory 73. The memory 73 stores a control program that is executed by the CPU 72. When the CPU 72 executes the control program, the processing circuit 71 controls the motor generator 40. <Funktionale Gestaltung der Regenerativkooperationssteuervorrichtung>

[0017] When CPU 62 executes the control program in memory 63, processing circuit 61 acts as a functional unit. When CPU 72 executes the control program in memory 73, processing circuit 71 acts as a functional unit.

[0018] As in Fig. As shown in Figure 2, the functional units comprise a target deceleration setting device M11, a regenerative cooperation control device M13, a starting vehicle speed setting device M15, a transition control device M17, a correction device M19, a friction brake control device M21, a regenerative brake control device M23, and a drive control device M25. The processing circuit 61 of the friction brake control unit 60 acts as the target deceleration setting device M11, the regenerative cooperation control device M13, the starting vehicle speed setting device M15, the transition control device M17, and the friction brake control device M21. The processing circuit 71 of the engine control unit 70 acts as the correction device M19, the regenerative brake control device M23, and the drive control device M25. The drive control device M25 corresponds to a "brake / drive control device". <Zielverzögerungseinstelleinrichtung>

[0019] When a braking request is received, the target deceleration setting device M11 sets a target deceleration DVSTr, which is a target for the deceleration of the vehicle 10. The target deceleration setting device M11 determines that a braking request has been issued when it detects that the brake actuation element 11 is being actuated, or when it receives a deceleration request from another control device. For example, when the brake actuation element 11 is actuated, the target deceleration setting device M11 sets the target deceleration DVSTr based on a detection signal from the brake sensor 51. <regenerativkooperationssteuereinrichtung>

[0020] The regenerative cooperation control unit M13 executes a regenerative cooperation process that calculates a regenerative braking force command value FxRTr and a friction braking force command value FxMTr based on the target deceleration DVSTr. The regenerative braking force command value FxRTr is a command value of a regenerative braking force FxR. The friction braking force command value FxMTr is a command value of a friction 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 of the braking force Fx of the vehicle 10. During the regenerative cooperation process, the regenerative cooperation control unit M13 calculates the regenerative braking force command value FxRTr and the friction braking force command value FxMTr such that the sum of these values ​​equals the target braking force FxTr. The regenerative cooperation control unit M13 can calculate the regenerative braking force command value FxRTr and the friction braking force command value FxMTr to maximize the regenerative braking force command value FxRTr. <startfahrzeuggeschwindigkeitseinstelleinrichtung>

[0022] The starting vehicle speed control device M15 sets a starting vehicle speed VS1Th, which represents the vehicle speed at the start of a transition control (described later). The starting vehicle speed control device M15 adjusts the starting vehicle speed VS1Th so that it is lower as the target deceleration DVSTr decreases. As will be described in detail later, a transition control is performed immediately before the vehicle comes to a complete stop. Accordingly, the starting vehicle speed VS1Th is set, for example, to 10 km / h or lower.

[0023] For example, the M15 starting vehicle speed setting device sets the starting vehicle speed VS1Th using the in Fig. The characteristic curve shown in section 3 applies. In this case, if the target deceleration DVSTr is less than a first deceleration DVS1, the starting vehicle speed control device M15 sets the starting vehicle speed VS1Th to a first vehicle speed VS1. If the target deceleration DVSTr is greater than or equal to a second deceleration DVS2, the starting vehicle speed control device M15 sets the starting vehicle speed VS1Th to a second vehicle speed VS2. The second deceleration DVS2 is greater than the first deceleration DVS1. The second vehicle speed VS2 is greater than the first vehicle speed VS1. If the target deceleration DVSTr is greater than or equal to the first deceleration DVS1 and less than the second deceleration DVS2, the starting vehicle speed control device M15 sets the starting vehicle speed VS1Th so that it increases as the target deceleration DVSTr increases. <Transitional control device>

[0024] To Fig. 2. Returning, the transition control device M17 performs a transition control for a transition from the regenerative braking force FxR to the friction braking force FxM in a situation where the regenerative braking force FxR is applied to the vehicle 10. The transition control device M17 initiates a transition control when the vehicle speed VS becomes less than or equal to the initial vehicle speed VS1Th. The vehicle speed VS is calculated based on the motor rotational speed Nmt.

[0025] The transition control comprises a main transition control and a preliminary transition control, which adjusts the deceleration rate of the regenerative braking force FxR so that it is lower than that during the main transition control. The transition control unit M17 executes the main transition control after the preliminary transition control has been executed.

[0026] Specifically, the transition control unit M17 initiates the preliminary transition control when the vehicle speed VS becomes less than or equal to the starting vehicle speed VS1Th. During preliminary transition control, the transition control unit M17 gradually increases the friction brake force command value FxMTr and gradually decreases the regenerative brake force command value FxRTr.

[0027] A process that calculates the instruction values ​​FxRTr and FxMTr during preliminary transition control is now implemented with reference to Fig. 4 described. Fig. Figure 4 is a characteristic map that represents the relationship between the vehicle speed VS and a pre-loaded friction braking force FxMp. The pre-loaded friction braking force FxMp represents the amount by which the friction braking force command value FxMTr is increased during the execution of the preliminary transition control.

[0028] At the in Fig. In the characteristic map shown in Figure 4, if the vehicle speed VS is higher than the starting vehicle speed VS1Th, the pre-loaded friction braking force FxMp is zero. A shift vehicle speed VS2Th is lower than the starting vehicle speed VS1Th. The shift vehicle speed VS2Th is set, for example, to a vehicle speed that serves as a criterion for determining whether the vehicle will stop. If the vehicle speed VS is less than or equal to the shift vehicle speed VS2Th, the pre-loaded friction braking force FxMp is maintained at a predetermined braking force FxMp1. If the vehicle speed VS is higher than the shift vehicle speed VS2Th and less than or equal to the starting vehicle speed VS1Th, the pre-loaded friction braking force FxMp increases as the vehicle speed VS decreases.

[0029] When the friction braking force FxM is increased from zero, a reaction delay in the friction braking force FxM is likely to occur at an initial increase. To address this issue, the predetermined braking force FxMp1 is set to a friction braking force that serves as a criterion for determining whether a reaction delay is likely to occur. The range of braking force at which a reaction delay in the friction braking force FxM occurs is determined, for example, by the specifications of the friction braking device 30 and the friction brake 20.

[0030] When the starting vehicle speed setting device M15 sets the starting vehicle speed VS1Th, the transition control device M17 generates the characteristic map as shown in Fig. 4 shown. The shift vehicle speed VS2Th is a preset vehicle speed and the predetermined braking force FxMp1 is a preset value. Accordingly, the transition control device M17, in accordance with the starting vehicle speed VS1Th, sets the slope of a characteristic curve Lmap, which is shown in Fig. As shown in Figure 4, the characteristic curve Lmap represents the area in which the vehicle speed VS decreases from the starting vehicle speed VS1Th to the switching vehicle speed VS2Th. The slope of the characteristic curve Lmap is the amount by which the preloaded friction braking force FxMp is increased with respect to a decrease in vehicle speed VS. This allows the transition control unit M17 to generate a characteristic curve. The transition control unit M17 updates the characteristic curve each time the starting vehicle speed VS1Th is updated. However, when the transition control unit M17 initiates the transition control, as soon as the vehicle speed VS becomes less than or equal to the starting vehicle speed VS1Th, the transition control unit M17 stops updating the characteristic curve.

[0031] In the preliminary transition control, the transition control device M17 obtains the pre-loaded friction braking force FxMp, which corresponds to the vehicle speed VS, from which in Fig. The characteristic map shown in Figure 4 is used. The transition control unit M17 then calculates a value, as the current value of the regenerative braking force command value FxRTr, which is obtained by subtracting the pre-loaded friction braking force FxMp from the regenerative braking force command value FxRTr. Furthermore, the transition control unit M17 calculates a value, as the current value of the friction braking force command value FxMTr, which is obtained by subtracting the current value of the regenerative braking force command value FxRTr from the target braking force FxTr.

[0032] If the vehicle speed VS becomes less than or equal to the shift vehicle speed VS2Th during the execution of the preliminary transition control, the transition control unit M17 terminates the preliminary transition control and initiates the main transition control. During the main transition control, the transition control unit M17 calculates the regenerative braking force command value FxRTr and the friction braking force command value FxMTr to satisfy the following conditions (A1) and (A2). (A1) The regenerative braking force command value FxRTr has become zero at the time when the vehicle speed VS becomes zero. (A2) While the regenerative braking force command value FxRTr is decreased with a constant slope, the friction braking force command value FxMTr is increased with the same slope. <korrektureinrichtung>

[0033] To Fig. 2. Returning during the execution of the transition control, the correction device M19 performs a correction process that corrects a difference ΔDVS between the regenerative braking force FxR and the friction braking force FxM, which has a higher reaction rate. This reduces the magnitude of the difference ΔDVS. The difference ΔDVS is between the deceleration DVS of vehicle 10 and the target deceleration DVSTr.

[0034] The friction braking device 30 is a hydraulic braking device that applies the friction braking force FxM to the vehicle 10 by increasing the hydraulic pressure in the wheel cylinder 21. Thus, especially when the braking force is relatively small, the reaction speed for the friction braking force FxM is lower than for the regenerative braking force FxR.

[0035] Thus, during the correction process, the correction device M19 corrects the regenerative braking force command value FxRTr from the regenerative braking force command value FxRTr and the friction braking force command value FxMTr, which are calculated by the transition control device M17, in accordance with the difference ΔDVS. For example, the correction device M19 corrects the regenerative braking force command value FxRTr by means of a feedback control in which the difference ΔDVS is used as an input.

[0036] The correction device M19 starts the correction process when the transition control is initiated and terminates the correction process immediately before the regenerative braking force FxR reaches zero. As described above, the transition control comprises the preliminary transition control and the main transition control. Thus, the correction device M19 can terminate the correction process when the transition control switches from the preliminary transition control to the main transition control. <reibungsbremssteuereinrichtung>

[0037] The friction brake control unit M21 controls the friction brake device 30. Specifically, the friction brake control unit M21 adjusts the friction brake force FxM by actuating the friction brake device 30 based on the friction brake force command value FxMTr. <regenerativbremssteuereinrichtung>

[0038] The regenerative braking control unit M23 causes the motor-generator 40 to act as a power generator, thereby controlling the regenerative braking force FxR. Specifically, the regenerative braking control unit M23 controls an inverter of the motor-generator 40, so that the motor-generator 40 generates more electrical power as the regenerative braking force command value FxRTr increases. Accordingly, the regenerative braking control unit M23 adjusts the regenerative braking force FxR in accordance with the regenerative braking force command value FxRTr. <antriebssteuereinrichtung>

[0039] When the vehicle 10 is stopped, the drive control unit M25 causes the motor-generator 40 to act as an electric motor, thereby controlling the driving force Fd. For example, if the vehicle 10 is stopped on a downhill slope, the drive control unit M25 operates the motor-generator 40 so that the driving force Fd is applied to the wheels 12 in the reverse direction. If the vehicle 10 is stopped on an uphill slope, the drive control unit M25 operates the motor-generator 40 so that the driving force Fd is applied to the wheels 12 in the forward direction. If the road surface on which the vehicle 10 is stopped is not inclined, the drive control unit M25 controls the motor-generator 40 so that the driving force Fd becomes zero.

[0040] However, after the vehicle 10 has come to a stop, the actuating force applied by the driver to the brake actuating element 11 may decrease. In this case, the drive control unit M25 actuates the motor generator 40 such that the driving force Fd, which corresponds to a creeping torque, is applied to the wheels 12. <bremsprozess>

[0041] On Fig. Referring to section 5, a braking process representing the processing flow in the regenerative cooperation control device 100 when the vehicle braking force Fx is adjusted is now described. The braking process is executed repeatedly for each predetermined control cycle. However, if the condition for executing a transition control is met, the execution of the braking process is stopped.

[0042] In step S11, the regenerative cooperation control device 100 determines whether a braking request has been issued. In the present embodiment, the processing circuit 61 of the friction brake control unit 60 acts as the target deceleration setting device M11 for executing the process of step S11. If it determines that a braking request has been issued (S11: YES), the regenerative cooperation control device 100 postpones the process to step S13. If it determines that no braking request has been issued (S11: NO), the regenerative cooperation control device 100 temporarily terminates the braking process.

[0043] In step S13, the regenerative cooperation control unit 100 sets the target delay DVSTr. In the present embodiment, the processing circuit 61 of the friction brake control unit 60 acts as the target delay setting device M11 for executing the process of step S13.

[0044] Subsequently, in step S15, the regenerative cooperation control device 100 converts the target deceleration DVSTr into the target braking force FxTr.

[0045] Next, in step S17, the regenerative cooperation control device 100 calculates the regenerative braking force command value FxRTr as the smaller of a value obtained by subtracting the friction braking force command value FxMTr from the target braking force FxTr and a regenerative braking force limit value FxRmax. The regenerative braking force limit value FxRmax is a maximum value of the regenerative braking force FxR that can be applied to the vehicle 10 by the motor generator 40. Subsequently, in step S19, the regenerative cooperation control device 100 calculates the friction braking force command value FxMTr as the larger of zero and a value obtained by subtracting the regenerative braking force command value FxRTr from the target braking force FxTr. In the present embodiment, the processing circuit 61 of the friction brake control unit 60 acts as the regenerative cooperation control device M13 for executing the processes of steps S17 and S19.

[0046] In step S21, the regenerative cooperation control device 100 actuates the motor generator 40 based on the regenerative braking force command value FxRTr and actuates the friction braking force device 30 based on the friction braking force command value FxMTr. In the present embodiment, the processing circuit 71 of the motor control unit 70 acts as the regenerative braking control device M23. As a result, a process that controls the motor generator 40 is executed during step S21. If the processing circuit 61 of the friction braking control unit 60 acts as the friction braking control device M21, a process that controls the friction braking device 30 is executed during step S21.

[0047] In step S23, for example, the regenerative cooperation control device 100 uses the one in Fig. Figure 3 shows a characteristic map for setting the starting vehicle speed VS1Th to a vehicle speed corresponding to the target deceleration DVSTr. In the present embodiment, the processing circuit 61 of the friction brake control unit 60 acts as the starting vehicle speed setting device M15 for executing the process of step S23.

[0048] Subsequently, at step S25, the regenerative cooperation control device 100 determines whether the vehicle speed VS is less than or equal to the initial vehicle speed VS1Th. If the vehicle speed VS is less than or equal to the initial vehicle speed VS1Th (S25: YES), the regenerative cooperation control device 100 determines that the condition for executing a transition control is met and terminates the braking process.

[0049] If the vehicle speed VS is higher than the starting vehicle speed VS1Th (S25: NO), the regenerative cooperation control device 100 determines that the condition for executing a transition control is not met and temporarily terminates the braking process. In this case, the regenerative cooperation control device 100 continues to execute the braking process repeatedly. <Transition process>

[0050] With reference to Fig. Section 6 now describes a transition time process that represents the processing flow in the regenerative cooperation control device 100 when a transition control is executed. The transition time process is executed repeatedly for each predetermined control cycle if the vehicle 10 has not yet stopped and the condition for executing a transition control is met.

[0051] At step S43, the regenerative cooperation control device 100 determines whether the vehicle speed VS is higher than the shift vehicle speed VS2Th. If it determines that the vehicle speed VS is higher than the shift vehicle speed VS2Th (S43: YES), the regenerative cooperation control device 100 executes the preliminary transition control. If it determines that the vehicle speed VS is less than or equal to the shift vehicle speed VS2Th (S43: NO), the regenerative cooperation control device 100 executes the main transition control.

[0052] The processing flow of the preliminary transition control is now described. First, at step S45, the regenerative cooperation control device 100 uses the process described in Fig. Figure 4 shows a characteristic map for adjusting the pre-loaded friction braking force FxMp to a braking force corresponding to the vehicle speed VS. Next, in step S47, the regenerative cooperation control device 100 calculates the regenerative braking force command value FxRTr as the smaller of a value obtained by subtracting the pre-loaded friction braking force FxMp from the target braking force FxTr and the regenerative braking force upper limit FxRmax. Subsequently, in step S49, the regenerative cooperation control device 100 calculates the friction braking force command value FxMTr as a value obtained by subtracting the regenerative braking force command value FxRTr from the target braking force FxTr. In the present embodiment, the processing circuit 61 of the friction brake control unit 60 acts as the transition control device M17 for executing the processes of steps S45 to S49.

[0053] Next, at step S51, the regenerative cooperation control device 100 calculates the difference ΔDVS between the target deceleration DVSTr and the actual deceleration DVS. This value is obtained by subtracting the vehicle 10's deceleration DVS from the target deceleration DVSTr. Subsequently, at step S53, the regenerative cooperation control device 100 performs the correction process, which corrects the regenerative braking force command value FxRTr, thus reducing the magnitude of the difference ΔDVS. In the present embodiment, the processing circuit 71 of the motor control unit 70 acts as the correction device M19 for executing the processes of steps S51 and S53. The regenerative cooperation control device 100 then shifts the process to step S59.

[0054] The processing flow of the main transition control is now described. First, in step S55, the regenerative cooperation control device 100 calculates a value as the current value of the regenerative braking force command value FxRTr, which is obtained by subtracting a transition braking force ΔFx2 from the regenerative braking force command value FxRTr. The transition braking force ΔFx2 is set to a value that satisfies the conditions (A1) and (A2) described above. Subsequently, in step S57, the regenerative cooperation control device 100 calculates a value as the friction braking force command value FxMTr, which is obtained by subtracting the current value of the regenerative braking force command value FxRTr from the target braking force FxTr. In the present embodiment, the processing circuit 61 of the friction braking control unit 60 acts as the transition control unit M17 for executing the processes of steps S55 and S57.Then the regenerative cooperation control device 100 shifts the process to step S59.

[0055] In step S59, the regenerative cooperation control device 100 actuates the motor generator 40 based on the regenerative braking force command value FxRTr and actuates the friction brake device 30 based on the friction brake force command value FxMTr. In the present embodiment, the processing circuit 71 of the motor control unit 70 acts as the regenerative brake control device M23. As a result, a process that controls the motor generator 40 is executed during step S59. When the processing circuit 61 of the friction brake control unit 60 acts as the friction brake control device M21, a process that controls the friction brake device 30 is executed during step S59. Then, the regenerative cooperation control device 100 temporarily terminates the transition time process. <nach-stopp-prozess>

[0056] With reference to Fig. Section 7 now describes a post-stop process that represents the processing flow at the regenerative cooperation control device 100 when the vehicle 10 is in a stopped state. The post-stop process is executed repeatedly for each predetermined control cycle.

[0057] At step S81, the regenerative cooperation control device 100 determines whether the vehicle 10 is in a stopped state. If it determines that the vehicle 10 is in a stopped state (S81: YES), the regenerative cooperation control device 100 postpones the process to step S83. If it determines that the vehicle 10 is not in a stopped state (S81: NO), the regenerative cooperation control device 100 temporarily terminates the post-stop process.

[0058] In step S83, the regenerative cooperation control device 100 determines whether the target braking force FxTr is less than or equal to a start-determining braking force FxA. To start the vehicle 10, the driver releases the brake actuating element 11. The target braking force FxTr has a value based on at least one of the actuation amount and the actuation force of the brake actuating element 11. Thus, the start-determining braking force FxA is set to a value that serves as a criterion for determining whether the driver intends to start the vehicle 10. If the target braking force FxTr is less than or equal to the start-determining braking force FxA (S83: YES), the regenerative cooperation control device 100 postpones the process to step S85. If the target braking force FxTr is greater than the start determining braking force FxA (S83: NO), the regenerative cooperation control device 100 shifts the process to step S87.

[0059] At step S85, the regenerative cooperation control device 100 adjusts the drive force Fd to a creep drive force Fc, which corresponds to a creep torque. The regenerative cooperation control device 100 then shifts the process to step S97.

[0060] In step S87, the regenerative cooperation control device 100 obtains slope information for a road surface on which the vehicle 10 is stopped. Specifically, the regenerative cooperation control device 100 obtains a road gradient. For example, the regenerative cooperation control device 100 uses the longitudinal acceleration GX to estimate the road gradient.

[0061] Subsequently, at step S89, the regenerative cooperation control device 100 determines whether the road surface on which the vehicle 10 is stopped is inclined. If it determines that the road surface is inclined (S89: YES), the regenerative cooperation control device 100 moves the process to step S91. If it determines that the road surface is not inclined (S89: NO), the regenerative cooperation control device 100 moves the process to step S93.

[0062] At step S91, the regenerative cooperation control device 100 adjusts the drive force Fd to a drive force in the reverse direction. Then, the regenerative cooperation control device 100 shifts the process to step S97.

[0063] In step S93, the regenerative cooperation control device 100 determines whether the road surface on which the vehicle 10 is stopped has an uphill slope. If it determines that the road has an uphill slope (S93: YES), the regenerative cooperation control device 100 postpones the process to step S95. If it determines that the road does not have an uphill slope (S93: NO), the regenerative cooperation control device 100 considers the road surface to be horizontal and thus temporarily terminates the post-stop process. In this case, the regenerative cooperation control device 100 does not apply the driving force Fd from the motor generator 40 to the wheels 12.

[0064] At step S95, the regenerative cooperation control device 100 adjusts the drive force Fd to a drive force in the forward direction. Then, the regenerative cooperation control device 100 shifts the process to step S97.

[0065] In step S97, the regenerative cooperation control device 100 drives the motor generator 40 such that the set drive force Fd is applied to the wheels 12. The regenerative cooperation control device 100 then temporarily terminates the after-stop process.

[0066] In the present embodiment, the processing circuit 71 of the motor control unit 70 acts as the drive control device M25 for executing the processes of steps S85 to S97. Operation and advantages of the present embodiment

[0067] The operation and advantages of the present embodiment will now be described with reference to Fig. 8 described.

[0068] At time t11, a braking request is generated while the vehicle 10 is in motion, for example, when the driver begins to actuate the brake actuator 11. Then, as described in section (B) of Fig. As shown in Figure 8, the target deceleration DVSTr gradually increases. Thus, the braking force Fx is applied to the vehicle 10 by executing the braking process.

[0069] Specifically, if the target braking force FxTr corresponding to the target deceleration DVSTr is less than or equal to the regenerative braking force limit FxRmax, a value equal to the target braking force FxTr is calculated as the regenerative braking force command value FxRTr, as described in section (C) of Fig. Figure 8 shows that the motor generator 40 is actuated based on the regenerative braking force command value FxRTr, which is calculated in this way. The friction braking force command value FxMTr is calculated as zero.

[0070] After time t12, the target deceleration DVSTr and the target braking force FxTr are determined as in section (B) of Fig. Figure 8 is maintained. Accordingly, after time t12, the starting vehicle speed VS1Th is maintained at a vehicle speed corresponding to the target braking force FxTr obtained at time t12.

[0071] When the regenerative braking force FxR is applied to the vehicle 10 in this way, the vehicle speed VS gradually decreases, as described in section (A) of Fig. 8 shown. Then, since the vehicle speed VS reaches the starting vehicle speed VS1Th at time t13, a transition control is started from time t13.

[0072] From time t13 onwards, the preliminary transition control is started as the transition control. During the preliminary transition control, the rate of decrease of the regenerative braking force command value FxRTr and the rate of increase of the friction braking force command value FxMTr are relatively low.

[0073] As described above, the friction braking force FxM is increased by supplying brake fluid to the wheel cylinder 21. Accordingly, the friction braking force FxM has a lower reaction rate than the regenerative braking force FxR. In particular, it is likely that at the initial time when hydraulic pressure is generated in the wheel cylinder 21, the friction braking force FxM and the friction braking force command value FxMTr will differ. If the friction braking force FxM and the friction braking force command value FxMTr differ, the deceleration DVS of the vehicle 10 will deviate from the target deceleration DVSTr.

[0074] To resolve this problem, when the preliminary transition control is executed, the regenerative cooperation control device 100 initiates the correction process. In this process, the regenerative braking force command value FxRTr is corrected to reduce the magnitude of the difference ΔDVS between the target deceleration DVSTr and the deceleration DVS of the vehicle 10. The friction brake device 30 is then actuated based on the friction braking force command value FxMTr, which is calculated by the preliminary transition control. Furthermore, the motor generator 40 is actuated based on the regenerative braking force command value FxRTr, which is corrected by the correction process. As a result, the reaction delay in the friction braking force FxM is compensated for by the regenerative braking force FxR. Accordingly, the sum of the friction braking force FxM and the regenerative braking force FxR is prevented from deviating from the target braking force FxTr.This enables the regenerative cooperation control device 100 to prevent the deceleration of the vehicle 10 from fluctuating due to the execution of the transition control.

[0075] The vehicle speed VS decreases, even during the execution of the preliminary transition control. Then, the vehicle speed VS reaches the switching vehicle speed VS2Th at time t14. In this case, since it is determined that the vehicle will stop at 10, the transition control switches from the preliminary transition control to the main transition control.

[0076] During the main transition control, the rate of decrease of the regenerative braking force command value FxRTr and the rate of increase of the friction braking force command value FxMTr are higher than during the execution of the preliminary transition control. At time t15, when the vehicle speed VS becomes zero, the regenerative braking force command value FxRTr becomes zero. That is, the transition from the regenerative braking force FxR to the friction braking force FxM is complete.

[0077] In general, as the vehicle speed VS approaches zero, the controllability of the regenerative braking force FxR decreases. Even if the controllability of the regenerative braking force FxR decreases, performing a correction process can increase the fluctuation in the vehicle's deceleration DVS 10.

[0078] In the present embodiment, the correction process is terminated when the main transition control is initiated. That is, in the regenerative cooperation control device 100, the correction process is initiated when the transition control is initiated and is terminated immediately before the regenerative braking force FxR reaches zero. This enables the regenerative cooperation control device 100 to prevent fluctuations in the deceleration DVS immediately before the vehicle 10 comes to a stop.

[0079] As described above, when the main transition control is initiated, the friction braking force command value FxMTr is set to be equal to the predetermined braking force FxMp1. Therefore, it is unlikely that the friction braking force response delay FxM will occur during the execution of the main transition control.

[0080] The present embodiment also achieves the following advantages.

[0081] (1) If the friction braking force command value FxMTr is significantly smaller than the predetermined braking force Fxmp1 at the start of the main transition control, the deceleration DVS may fluctuate due to a reaction delay in the friction braking force FxM during the execution of the main transition control. If the friction braking force command value FxMTr is significantly larger than the predetermined braking force FxMp1 at the start of the main transition control, it is possible that the preliminary transition control will be executed for an excessively long time, resulting in a reduction in regenerative energy recovery efficiency.

[0082] To solve this problem, the Regenerative Cooperation Control Device 100 sets the starting vehicle speed VS1Th to decrease as the target deceleration DVSTr decreases. This allows the starting point of the preliminary transition control to be adjusted 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 transition control. Furthermore, if the target deceleration DVSTr is relatively low, the preliminary transition control is prevented from starting too early. This allows the Regenerative Cooperation Control Device 100 to prevent fluctuations in the deceleration DVS during the execution of the main transition control, while preventing a reduction in regenerative energy recovery efficiency during vehicle braking.

[0083] (2) It is possible that the creeping driving force Fc continues to be applied to the wheels 12 of the vehicle 10 as the driving force Fd after the vehicle 10 stops. In this case, the driving force Fd continues to be applied to the wheels 12 even though the driver does not intend to start the vehicle 10. Thus, the energy efficiency of the vehicle 10 cannot be considered relatively high.

[0084] In the case of the regenerative cooperation control device 100, if it is determined that the vehicle 10 is not stopped on an inclined road, the driving force Fd is not applied to the vehicle 10. This allows the regenerative cooperation control device 100 to prevent unnecessary consumption of electrical energy while the vehicle 10 is in a stopped state.

[0085] However, if it is determined that vehicle 10 has stopped on a downhill road, as in section (D) of Fig. As shown in Figure 8, the driving force in the reverse direction is applied to the wheels 12 as the driving force Fd. When the vehicle 10 is stopped on a sloping road, the driving force in the reverse direction acts on the vehicle 10 as a force that prevents the vehicle 10 from rolling downhill due to its own weight. That is, when the vehicle 10 is stopped on a sloping road, the regenerative cooperation control device 100 prevents the vehicle 10 from rolling downhill due to its own weight by applying the driving force in the reverse direction to the wheels 12.

[0086] When it is determined that the vehicle 10 is stopped on an uphill road, a forward force is applied to the wheels 12 as the driving force Fd. When the vehicle 10 is stopped on an uphill road, the forward driving force acts on the vehicle 10 as a force that prevents the vehicle 10 from rolling downhill due to its own weight. That is, when the vehicle 10 is stopped on an uphill road, the regenerative cooperation control device 100 prevents the vehicle 10 from rolling downhill due to its own weight by applying the forward driving force to the wheels 12.

[0087] However, if the target braking force FxTr is less than or equal to the start-determination braking force FxA while the vehicle 10 is in a stopped state, it is assumed that the driver intends to start the vehicle 10. Accordingly, when the target braking force FxTr becomes less than or equal to the start-determination braking force FxA, the creep drive force Fc is applied to the wheels 12 as the drive force Fd. This enables the regenerative cooperation control direction 100 to contribute to a swift start of creep travel of the vehicle 10 when the driver releases the brake actuation. Variations

[0088] The embodiment described above can be modified as follows. The embodiment described above and the following modifications can be combined, provided that the combined modifications remain technically consistent with each other. - The regenerative cooperation control device does not need to apply the driving force in the forward direction to the wheels 12 when the vehicle 10 stops on an uphill road, as long as it applies the driving force in the reverse direction to the wheels 12 when the vehicle 10 stops on a downhill road. Conversely, the regenerative cooperation control device does not need to apply the driving force in the reverse direction to the wheels 12 when the vehicle 10 stops on a downhill road, as long as it applies the driving force in the forward direction to the wheels 12 when the vehicle 10 stops on an uphill road. - The regenerative cooperation control device does not need to apply the drive force Fd to the wheels 12, even if the target braking force FxTr is less than or equal to the start-determining braking force FxA, while the vehicle 10 is in a stopped state. - The starting vehicle speed VS1Th does not need to be varied in accordance with the target deceleration DVSTr. For example, the starting vehicle speed VS1Th can be a predetermined vehicle speed that has been preset to be higher than the switching vehicle speed VS2Th. Even in this case, if the vehicle speed VS becomes less than or equal to the switching vehicle speed VS2Th, the transition control switches from the preliminary transition control to the main transition control. Thus, if the starting vehicle speed VS1Th is fixed at the predetermined vehicle speed, the rate of reduction in regenerative braking force FxR can be lowered, as can the target deceleration DVSTr when the preliminary transition control is activated. The transition control need not include the preliminary transition control as long as it includes the main transition control. In this case, the regenerative cooperation control device initiates the main transition control when the vehicle speed VS becomes less than or equal to the starting vehicle speed. Furthermore, the regenerative cooperation control device corrects the regenerative braking force command value FxRTr, calculated by the main transition control, using the correction process, so that the magnitude of the difference ΔDVS between the target deceleration DVSTr and the deceleration DVS is reduced. However, it is preferred that the regenerative cooperation control device terminates the correction process during an execution of the main transition control. - In the embodiment described above, the correction process is terminated when the transition control switches from the preliminary transition control to the main transition control. However, as long as the correction process is terminated immediately before the vehicle speed VS reaches zero, it can be terminated during the execution of the main transition control. In such a case, if the correction process itself is executed during the execution of the main transition control, it is preferred to make the feedback control gain smaller than that used during the execution of the preliminary transition control. The friction braking device can be an electric braking device designed to apply a friction braking force to wheel 12 that corresponds to a rotation angle of an electric motor. When such an electric braking device is used as the friction braking device, the reaction rate for the friction braking force FxM can be higher than that for the regenerative braking force FxR. If the friction braking force FxM has a higher reaction rate than the regenerative braking force FxR, the friction braking force command value FxMTr can be corrected during the correction process, thus reducing the magnitude of the difference ΔDVS between the target deceleration DVSTr and the deceleration DVS. If the friction braking force FxM has a lower reaction rate than the regenerative braking force FxR, the regenerative braking force command value FxRTr can be corrected during the correction process, thus reducing the magnitude of the difference ΔDVS. The braking force corrected by the correction process is defined as a target correction braking force. In the embodiment described above, the target correction braking force is set to the braking force that results in a higher reaction rate from the regenerative braking force and the friction braking force. However, this configuration is not mandatory. For example, the target correction braking force can be determined based on the control precision and the amount of data to be used. For instance, the target correction braking force could be one of the regenerative braking forces and the friction braking force that offers higher control precision. Alternatively, the target correction braking force could be one of these that uses a smaller amount of data.

[0089] The processing circuit 61 and 71 can be a circuit comprising one or more processors running according to a computer program, one or more dedicated hardware circuits performing at least part of various processes, or a combination thereof. Examples of dedicated hardware circuits include an application-specific integrated circuit (ASIC). The processors comprise a central processing unit (CPU) and memory, such as main memory (RAM) and read-only memory (ROM), and the memory stores program code or instructions designed to cause the CPU to execute processes. The memory, namely a computer-readable medium, comprises any available medium that can be read by a general-purpose or special-purpose computer.

[0090] The phrase "at least one of," as used in this specification, means one or more of the desired options. For example, if there are two options, the phrase "at least one of," as used in this specification, means either a single option or both options. As another example, if there are three or more options, the phrase "at least one of," as used in this specification, means a single option or any combination of two or more of these options. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2010 / 128652 A

[0003] < / bremsprozess> < / antriebssteuereinrichtung> < / regenerativbremssteuereinrichtung> < / reibungsbremssteuereinrichtung> < / korrektureinrichtung> < / startfahrzeuggeschwindigkeitseinstelleinrichtung> < / regenerativkooperationssteuereinrichtung> < / regenerativkooperationssteuervorrichtung> < / sensor> < / motorgenerator> < / reibungsbremsvorrichtung> < / reibungsbremse>

Claims

[1] Regenerative cooperation control device used in a vehicle, the vehicle comprising a regenerative braking device designed to apply a regenerative braking force and a friction braking device designed to apply a friction braking force, the regenerative cooperation control device comprising: a transition control device designed to perform transition control for a transition from the regenerative braking force to the friction braking force in a situation where the regenerative braking force is applied to the vehicle; and a correction device designed to perform a correction process that corrects a difference between the regenerative braking force and the friction braking force, which has a higher reaction speed, so that the magnitude of the difference between the deceleration of the vehicle and a target deceleration during an execution of the transition control is reduced. [2] Regenerative cooperation control device according to claim 1, wherein The friction braking device comprises a hydraulic pressure braking device designed to apply the friction braking force by increasing a hydraulic pressure in a wheel cylinder, and During the correction process, the correction device corrects the regenerative braking force, thus reducing the magnitude of the difference between the vehicle's deceleration and the target deceleration. [3] Regenerative cooperation control device according to claim 1, wherein The correction device is designed to start the correction process when the transition control is started and to end the correction process immediately before the regenerative braking force becomes zero. [4] Regenerative cooperation control device according to any one of claims 1 to 3, wherein the transition control device is designed to initiate transition control when a vehicle speed becomes less than or equal to a starting vehicle speed, and The regenerative cooperation control device further comprises a starting vehicle speed adjustment device designed to adjust the starting vehicle speed to a lower vehicle speed as the target deceleration decreases. [5] Regenerative cooperation control device according to claim 4, wherein The transition control comprises a main transition control and a preliminary transition control, which sets a rate of reduction of the regenerative braking force such that it is lower than a rate of reduction of the regenerative braking force during an execution of the main transition control, and the transitional control device is designed for this purpose: to start the preliminary transition control when the vehicle speed becomes less than or equal to the starting vehicle speed; and to terminate the preliminary transition control and initiate the main transition control when the vehicle speed becomes less than or equal to a shift vehicle speed that is lower than the starting vehicle speed. [6] Regenerative cooperation control device according to claim 1, wherein The regenerative braking device is a braking / drive device designed to apply either a regenerative braking force or a driving force to a wheel of the vehicle, and The regenerative cooperation control device further comprises a brake / drive control device designed to control the brake / drive device so that the drive force is applied to the wheel to rotate it in a reverse direction when the vehicle stops on a downhill slope. [7] Regenerative cooperation control device according to claim 1, wherein in the transition control the transition control device reduces the regenerative braking force so that the regenerative braking force becomes zero when a vehicle speed becomes zero. [8] Regenerative cooperation control method used in a vehicle, the vehicle comprising a regenerative braking device designed to apply a regenerative braking force and a friction braking device designed to apply a friction braking force, the regenerative cooperation control method comprising: Executing a transition control for a transition from regenerative braking force to friction braking force in a situation where regenerative braking force is applied to the vehicle; and Executing a correction process that corrects for the difference between the regenerative braking force and the friction braking force, which has a higher reaction speed, so that the magnitude of the difference between the vehicle's deceleration and the target deceleration during the execution of the transition control is reduced.

Images