JP2014075869A - Rollback suppression control device of electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rollback suppression control device of an electric vehicle making it possible to improve responsiveness of an electric motor in an electric vehicle, and making it easy to escape from a rollback state.SOLUTION: A rollback suppression control device 64 suppresses rollback of an electric vehicle that drives wheels thereof using an electric motor. The rollback suppression control unit 64 includes a rotation angle sensor 66 that detects the rotation angle of the electric motor, a lever position sensor 93a that detects a shift position of the vehicle, rollback state detection means 65 that detects a rollback state of the vehicle on the basis of the rotation angle detected by the rotation angle sensor 66 and the shift position detected by the lever position sensor 93a, and rollback suppression control means 67 that when the rollback state detection means 65 detects that the vehicle is in the rollback state, suppresses the rollback of the vehicle.

Description

  The present invention relates to a rollback suppression control device for an electric vehicle in consideration of reduction of shock torque caused by a clutch of a transmission unit in the electric vehicle.

  In a vehicle of an electric vehicle, there is a problem that the speed increases in a state where the vehicle rolls back in a direction opposite to the traveling direction when starting. Therefore, it is necessary to immediately detect the rollback state of the vehicle and suppress the rollback.

  When the vehicle is temporarily stopped on a steep slope, if the creep torque is insufficient, the vehicle may move backward until the brake is released and the accelerator is depressed. Such a state is called a rollback state. Specifically, when the vehicle starts on a slope, if the slope is steep, the brake position is released and the accelerator is depressed while the shift position is in the forward range such as “D” or “1”. In addition, the creep torque is reduced due to the horizontal component of the force represented by the product of the vehicle weight and gravity, the resistance force received from the road surface, etc., so that the wheels rotate in the vehicle backward direction. Alternatively, the wheel rotates in the vehicle forward direction in a state where the shift position is in the reverse range of “R”.

JP-A-1-99410 JP 2006-31644 A

Positive direction: The direction in which the roller clutch is fastened when the electric motor is driven.
Negative direction: When the electric motor is regenerated, the roller clutch is engaged.

  A technique has been proposed in which when a vehicle rollback is detected, the motor voltage is immediately maximized to suppress the vehicle rollback (Patent Document 1). However, there is a problem that the vehicle is likely to cause sudden acceleration, wheel slip, and the like.

  When a rollback is detected, a vehicle driving technique is proposed that increases the driving force in the vehicle traveling direction of the electric motor compared to when no rollback is detected (Patent Document 2). In this technique, an operation of increasing or decreasing the output torque of the electric motor is performed in accordance with the vehicle speed at the time of rollback. However, when the electric motor is controlled in accordance with the vehicle speed, there is a problem that the responsiveness of the electric motor is lowered, and there is a drawback that it is difficult to escape from the rollback.

  In the transmission control method for the vehicle motor drive device of the present applicant (Japanese Patent Application No. 2011-123433), it is necessary to increase the torque value of the electric motor in order to escape from the rollback state. Since the roller clutch of the current gear stage is quickly engaged in the positive direction by increasing the torque, shock torque and noise are likely to occur.

  An object of the present invention is to provide a rollback suppression control device for an electric vehicle that improves the responsiveness of the electric motor and easily escapes from the rollback state in an electric vehicle.

  The rollback suppression control device 64 of the electric vehicle EV according to the present invention is a rollback suppression control device that suppresses a rollback in which the vehicle moves in the direction opposite to the traveling direction when the vehicle starts, in an electric vehicle in which the wheels 1 are driven by the electric motor 3. A rotation angle sensor 66 for detecting the rotation angle of the electric motor 3, a shift position detection sensor 93a for detecting a shift position of the vehicle, a rotation angle detected by the rotation angle sensor 66, and the shift position detection sensor. A rollback state detection means 65 for detecting a rollback state of the vehicle from the shift position detected at 93a, and when the vehicle is detected as a rollback state by the rollback state detection means 65, the roll of the vehicle is detected. Having roll back suppression control means 67 for suppressing back And features.

  According to this configuration, the rotation angle sensor 66 detects the rotation angle of the electric motor 3. The shift position detection sensor 93a detects a shift position of the vehicle, for example, a drive range, a second speed range, a first speed range, a reverse range, and the like. Rollback state detection means 65 detects the rollback state of the vehicle from the rotation angle detected by rotation angle sensor 66 and the shift position detected by shift position detection sensor 93a. The rollback suppression control means 67 controls, for example, the torque of the electric motor 3 so that the rollback of the vehicle is suppressed when the rollback state detection means 65 detects that the vehicle is in the rollback state. By suppressing the rollback of the vehicle in this way, the responsiveness of the electric motor 3 can be improved and the vehicle can easily escape from the rollback state.

  The rollback suppression control means 67 may control the torque of the electric motor 3 according to the rotation angle of the rotation angle sensor 66 in the rollback state of the vehicle. In this case, the electric motor is not controlled according to the vehicle speed as in the prior art, but the torque of the electric motor 3 is controlled according to the rotation angle of the rotation angle sensor 66. It can be solved more reliably. Therefore, the vehicle can be easily escaped from the rollback state.

  The rollback suppression control means 67 increases the rotation angle obtained by subtracting the rotation angle that is a predetermined time from the rotation angle detected by the rotation angle sensor 66 in the rollback state of the vehicle. The larger the value is, the larger the torque of the electric motor 3 is. The smaller the increase in the rotation angle is, the smaller the torque of the electric motor 3 is. Thus, by changing the torque of the electric motor 3 finely according to the increase in the rotation angle, the responsiveness of the electric motor 3 can be improved reliably, and it is easier to escape from the rollback state more reliably. it can. Further, for example, by performing control to gradually increase the torque of the electric motor 3 in accordance with the increase in the rotation angle, for example, it is possible to reduce shock torque and noise caused by the transmission 5.

The rollback suppression control means 67 may keep the torque of the electric motor 3 constant after switching the rotation direction of the electric motor 3 from the counterclockwise direction to the forward clockwise direction. In this case, it is possible to enter a so-called creep control state that escapes from the rollback state and does not become the rollback state again.
The rollback suppression control means 67 switches the electric motor 3 in response to the accelerator signal command when the accelerator signal command exceeds a predetermined value after switching the rotation direction of the electric motor 3 from the counterclockwise direction to the forward clockwise direction. It is good also as what controls.

The electric vehicle EV may drive one or both of the front and rear wheels 1 and 2 of the vehicle with the electric motor 3.
The electric vehicle may be configured such that one of the front and rear wheels 1 and 2 of the vehicle is driven by the engine E and the other of the front and rear wheels 1 and 2 is driven by the electric motor 3.

  The rollback suppression control device for an electric vehicle according to the present invention is a rollback suppression control device that suppresses a rollback in which the vehicle moves in the direction opposite to the traveling direction when starting, in an electric vehicle in which wheels are driven by an electric motor. From the rotation angle sensor that detects the rotation angle of the motor, the shift position detection sensor that detects the shift position of the vehicle, the rotation angle that is detected by the rotation angle sensor, and the shift position that is detected by the shift position detection sensor, Rollback state detection means for detecting a rollback state of the vehicle, and rollback suppression control means for suppressing rollback of the vehicle when the vehicle is detected as a rollback state by the rollback state detection means. Have. For this reason, in the electric vehicle, it is possible to improve the response of the electric motor and to easily escape from the rollback state.

1 is a schematic diagram of an electric vehicle to which a rollback suppression control device and a rollback suppression control method according to an embodiment of the present invention are applied. It is the schematic of the hybrid vehicle to which the same rollback suppression control device and rollback suppression control method are applied. FIG. 3 is a schematic block diagram of a shift control system that controls the vehicle motor drive device for the vehicle shown in FIGS. 1 and 2. It is a block diagram of the inverter apparatus of the motor drive apparatus for vehicles. It is explanatory drawing of the shift lever operation panel of the vehicle. It is a block diagram of the inverter control apparatus of the motor drive device for vehicles. It is a block diagram which shows the conceptual structure of the rollback suppression control apparatus of the motor drive device for vehicles. It is a figure which shows the change of the rotation angle sensor signal at the time of driving | running | working in the drive range of a vehicle in the rollback suppression control apparatus. It is a figure which shows the change condition of the rotation angle sensor signal according to the rotation speed change at the time of driving | running | working in the drive range of a vehicle in the same rollback suppression control apparatus. It is a figure which shows the change of the rotation angle sensor signal at the time of driving | running | working in the reverse range of a vehicle in the same rollback suppression control apparatus. It is a figure which shows the change condition of the rotation angle sensor signal according to the rotation speed change at the time of driving | running | working in the reverse range of a vehicle in the same rollback suppression control apparatus. It is a figure which shows the waveform of a rotation angle sensor signal when the rotation direction of an electric motor switches from a counterclockwise direction to a forward clockwise direction in the same rollback suppression control apparatus. It is a figure which shows the waveform of a rotation angle sensor signal when the rotation direction of an electric motor switches from a forward clockwise direction to a counterclockwise direction in the same rollback suppression control apparatus. 5 is a flowchart of an interrupt function for detecting a rollback state in the electric vehicle. 4 is a time chart of a rollback that occurs in a state where the shift position is in a forward range such as “D” and “1” in the electric vehicle.

Hereinafter, a rollback suppression control device and a rollback suppression control method for an electric vehicle according to an embodiment of the present invention will be described. FIG. 1 shows an electric vehicle EV in which a pair of left and right front wheels 1 are drive wheels driven by a vehicle motor drive device A, and a pair of left and right rear wheels 2 are driven wheels.
FIG. 2 shows a hybrid vehicle HV in which a pair of left and right front wheels 1 are main drive wheels driven by an engine E, and a pair of left and right rear wheels 2 are auxiliary drive wheels driven by a vehicle motor drive device A. The hybrid vehicle HV is provided with a transmission T for shifting the rotation of the engine E and a differential D for distributing the rotation output from the transmission T to the left and right front wheels 1. The rollback suppression control device and the rollback suppression control method of this embodiment are applied to the vehicle motor drive device A shown in FIGS.

  FIG. 3 is a block diagram showing a control system for controlling the vehicle motor drive device A. As shown in FIG. This control system has an integrated ECU 60, a transmission ECU 61, and an inverter device 62. Signal transfer among the three units of the integrated ECU 60, the shift ECU 61, and the inverter device 62 is performed by CAN communication (controller area network).

  The integrated ECU 60 is an electronic control device that performs cooperative control among all on-vehicle electronic control devices, and includes an accelerator opening sensor 63a of the accelerator pedal 63, a brake opening sensor 91a of the brake pedal 91, and a steering angle sensor 92a of the steering wheel 92. The shift lever 93 is manually connected to a shift position detection sensor (lever position sensor) 93a for switching the gear position. The integrated ECU 60 shifts the accelerator position sensor 63a, the brake position sensor 91a, the steering angle sensor 92a, the accelerator position signal detected by the lever position sensor 93a, the brake position signal, the steering angle signal, and the lever position signal. A function to transmit to the ECU 61 and a function to perform the cooperative control by these four types of signals and signals from various other sensors and the like are provided.

  The shift ECU 61 is an electronic control device that controls automatic shift based on various signals transmitted from the integrated ECU 60 and various signals directly input to the shift ECU 61. The shift ECU 61 performs shift determination based on various input signals, Commands are sent to the gear change actuator 47 and the inverter device 62 of the machine 5.

The rollback suppression control device and the rollback suppression control method of this embodiment relate to control in the transmission ECU 61. The transmission ECU 61 has various function achievement means shown in FIG. 7, and these means will be described later.
The transmission ECU 61 has the following functions (1) to (7).
(1) The vehicle speed sensor 94 and the acceleration sensor 95 receive vehicle speed and vehicle acceleration / deceleration detection signals, the accelerator opening signal is received from the integrated ECU 60, and automatic shift determination is performed.
(2) If it is determined that the brake is sudden, both new automatic shift and manual shift are not performed.
(3) If it is determined that the handle is a sudden handle, neither new automatic gear shift nor manual gear shift is performed.
(4) A position signal of the shift lever 93 is received from the integrated ECU 60, and creep control of the electric motor is performed.

  (5) A manual transmission function is provided.

(6) A function of detecting the shift position of the shift switching actuator 47 from a shift position sensor 68 attached to the transmission 5 and a function of acquiring the rotational speed of the electric motor 3 from the inverter device 62 are provided.
(7) A function of transmitting a torque command or a rotational speed command and a shift command to the inverter device 62 and a function of driving a shift switching actuator 47 attached to the transmission 5 are provided.

  In FIG. 3, the inverter device 62 is supplied with DC power from a battery 69 to supply AC motor driving power to the electric motor 3, and controls the supplied power based on a signal from the transmission ECU 61. A signal indicating the number of rotations of the electric motor 3 is input to the inverter device 62 from a rotation angle sensor 66 provided in the electric motor 3.

The inverter device 62 has a function of driving the electric motor 3 and a function of obtaining a rotation angle signal of the electric motor 3 from the rotation angle sensor 66. As shown in FIG. 4, the inverter device 62 includes an inverter 71 and an inverter control circuit 72 that controls the inverter 71. Each phase of the electric motor 3 (at the connection point of the inverter 71, U, V, W phase upper arm switching elements Up, Vp, Wp and U, V, W phase lower arm switching elements Un, Vn, Wn) U, V, W phase) terminals are connected. To the inverter 71, an open / close command is given to each switching element Up, Vp, Wp, Un, Vn, Wn from the inverter control circuit 72 so as to output three-phase AC power.
The electric motor 3 performs commutation by energization of three phases. A large current is required to drive the electric motor 3.

  FIG. 5 shows the configuration of the shift lever operation panel 75. As the driver manually operates the shift lever 93 (FIG. 3), P (parking), R (reverse), N (neutral), D (drive), 2nd speed (second), Each shift position (each shift range) of the first speed (low) can be switched. The shift lever operation panel 75 is a display device that indicates which shift position is currently switched in this way. Range selection information on the shift lever operation panel 75 is input to the integrated ECU 60 (FIG. 3). The first speed range is the first speed state. Note that the shift lever operation panel 75 may serve as a touch panel type input means, for example, and may be an operation means operated by a driver instead of the shift lever 93 (FIG. 3).

FIG. 6 shows a block diagram of the electric motor 3, inverter torque control, and inverter rotation speed control. The inverter control circuit 72 can be controlled by switching between torque control and rotation speed control. Both torque control and rotation speed control are feedback control and vector control. Torque control and rotation speed control are performed at the time of shifting, and torque control is performed at times other than shifting.
The power converter 62a performs PWM control of the inverter 71 according to the PWM duties Vu, Vv, and Vw, and drives the electric motor 3.

The rotation speed control by the inverter control circuit 72 of FIG.
The speed command unit 106 is a means for giving a speed command to the inverter control circuit 72 and is provided in the speed change ECU 61. The speed command unit 106 calculates a target rotational speed of the electric motor 3 based on the vehicle speed at the time of shifting and the speed ratio of the selected target shift stage. The calculated target rotational speed is instructed to the inverter control circuit 72 of the inverter device 62 as a speed command.

Further, the rotor angle of the electric motor 3 is acquired from the rotation angle sensor 66, and the actual rotation speed of the electric motor 3 is calculated by the speed calculation unit 108. The comparison unit 109 obtains the difference between the speed command of the speed command unit 106 and the actual electric motor speed calculated by the speed calculation unit 108, and the control unit 107 performs PID control (proportional integral derivative control) for the difference. Alternatively, PI control (proportional integral control) is performed, and the control amount is input to the current command unit 101 as a torque command. During the rotation speed control, a torque command based on the speed command from the speed calculation unit 108 is input to the current command unit 101 instead of the torque command from the torque command unit 110.
In the rotational speed control, the target rotational speed of the electric motor 3 is calculated at a constant time interval, and even if the vehicle speed changes suddenly during the shift, the target rotational speed of the shift has a feature that can follow the change in the vehicle speed. Thereby, the shift shock can be reduced.

In FIG. 6, the inverter control circuit 72 is described by being divided into a speed control unit 73 and a torque control unit 74.
The torque control unit 74 is a part of the inverter control circuit 72 that performs the function of controlling the electric motor 3 by torque control. The current command unit 101, the current PI control unit 102, the two-phase / three-phase change units 103, 3 A phase / two-phase change unit 104, a speed calculation unit 108, and a prediction unit 111 are included.
The speed control unit 73 is a part of the inverter control circuit 72 that performs the function of controlling the electric motor 3 by speed control. The speed control unit 73 includes a comparison unit 109 and a control unit 107. A torque command is given to the unit 101, and the subsequent control is performed by the torque control unit 74.

Next, a rollback suppression control device for a vehicle motor drive device in an electric vehicle will be described with reference to the block diagram of FIG. The electric vehicle to be controlled is the aforementioned electric vehicle.
The rollback suppression control device 64 is a device that suppresses rollback in which the vehicle moves in the direction opposite to the traveling direction at the time of starting in an electric vehicle in which wheels are driven by the electric motor 3. The rollback suppression control device 64 includes a rotation angle sensor 66, a lever position sensor 93 a that detects a shift position, a rollback state detection unit 65, and a rollback suppression control unit 67.

  The rollback state detection means 65 detects the rollback state of the vehicle from the rotation angle detected by the rotation angle sensor 66 and the shift position detected by the lever position sensor 93a. The details will be described later with reference to FIG. Here, the rollback state refers to a state in which the vehicle is actually moving in the direction opposite to the traveling direction when starting. The rollback suppression control means 67 shown in FIG. 7 is a torque of the electric motor 3 (FIG. 6) so as to suppress the rollback of the vehicle when the rollback state detection means 65 detects that the vehicle is in a rollback state. To control. The shift ECU 61 is provided with these rollback state detection means 65 and rollback suppression control means 67. The transmission ECU 61 is provided with a memory 70 such as a ROM. In the storage area of the memory 70, for example, values input from various sensors, switches, and the like are temporarily stored for calculation. In the storage area of the memory 70, a drive creep threshold, which will be described later, and other necessary thresholds are appropriately stored.

  FIG. 8 is a diagram illustrating a change in the rotation angle sensor signal during traveling in the vehicle drive range in the rollback suppression control device. This will be described with reference to FIG. An analog signal having an electrical angle of 360 ° of the rotation angle sensor 66 provided in the electric motor 3 is converted into an n-bit digital value, for example, and the electrical angle 360 ° is expressed by an AD value of the rotation angle sensor signal. For example, in the case of using a shaft with double shaft angle 6X, when the rotor of the electric motor 3 makes one rotation (mechanical angle 360 °), six sawtooth waves are output as the signal of the rotation angle sensor 66. One sawtooth wave represents a mechanical angle of 60 ° (electrical angle of 360 °).

  Further, when the rotor of the electric motor 3 is rotated in the CCW (counterclockwise) direction, the value of the rotation angle sensor 66 increases from 0 to a set value. Increases from to the set value. The movement is to be repeated. The number of rotations (rpm) of the electric motor 3 can be calculated using the amount of change in the rotation angle sensor signal at a constant sampling time. The rotation direction of the electric motor 3 is the direction seen from the output shaft side of the electric motor 3.

A method for calculating the rotation speed of the electric motor 3 will be described.
Assuming that the sampling time for acquiring the rotation angle sensor signal is Δt, the amount of change in the rotation angle sensor signal is Δth, and the shaft multiplication angle is 6 ×, for example, the rotation speed rot [rpm] of the electric motor 3 is obtained as follows. .

FIG. 9 is a diagram showing a change state of the rotation angle sensor signal in accordance with a change in the rotation speed during traveling in the drive range of the vehicle in the rollback suppression control device.
FIG. 9 shows the change state of the rotation angle sensor signal according to the case where the rotation direction of the electric motor 3 is CCW (counterclockwise) when viewed from the output shaft side of the electric motor 3 and the rotation speed rot2>rot1> rot3. Represents. The faster the rotation speed of the electric motor 3, the greater the number of sawtooth waves of the rotation angle sensor 66 output within a certain time. Conversely, the slower the rotation speed of the electric motor 3, the smaller the number of sawtooth waves of the rotation angle sensor 66 output within a certain time.

  FIG. 10 is a diagram illustrating changes in the rotation angle sensor signal when the vehicle travels in the reverse range of the rollback suppression control device. This will be described with reference to FIG. FIG. 10 shows a change state of the AD value of the rotation angle sensor signal when the rotor of the electric motor 3 rotates in the CW (forward clock direction) when viewed from the output shaft side of the electric motor 3. When the value of the rotation angle sensor 66 decreases from the set value to 0 and reaches 0, the value returns to the set value and decreases from the set value to 0 again. The movement is to be repeated.

FIG. 11 is a diagram illustrating a change state of the rotation angle sensor signal according to the change in the rotation speed when the vehicle travels in the reverse range in the rollback suppression control device.
FIG. 11 shows the change state of the rotation angle sensor signal according to the case where the rotation direction of the electric motor 3 is CW (forward clock direction) when viewed from the output shaft side of the electric motor 3 and the rotation speed rot2>rot1> rot3. Represents. The faster the rotation speed of the electric motor 3, the greater the number of sawtooth waves of the rotation angle sensor 66 output within a certain time. Conversely, the slower the rotation speed of the electric motor 3, the smaller the number of sawtooth waves of the rotation angle sensor 66 output within a certain time.

  FIG. 12 is a diagram illustrating a waveform of the rotation angle sensor signal when the rotation direction of the electric motor is switched from the counterclockwise direction to the forward clockwise direction in the rollback suppression control device. Normally, the electric motor rotor rotates CCW (counterclockwise) while the shift position is in the forward range such as “D”, “1”, etc., while the shift position is in the reverse range of “R”. Thus, the rotor of the electric motor rotates in CW (forward clockwise direction). When the shift position is in the “P” and “N” ranges, the rotor of the electric motor does not rotate. In the CCW rotation direction of the figure, the value of the rotation angle sensor 66 (FIG. 3) increases from 0 to the set value, and when this set value is reached, it returns to 0 and repeats from 0 to the set value again. Perform the action.

  On the other hand, in the rotation direction of CW in the figure, the value of the rotation angle sensor 66 (FIG. 3) decreases from the set value to 0, and when it reaches 0, returns to the set value and decreases again from the set value to 0. Repeat operations like this. For example, in this example, when the rotor of the electric motor is switched from CCW to CW, switching is performed when the value of the rotation angle sensor 66 (FIG. 3) is a set value. This set value is maintained for a predetermined time at the time of switching. The rotational speed of the electric motor in the CCW rotational direction before switching to CW is set slower than the previous rotational speed.

  FIG. 13 is a diagram illustrating a waveform of the rotation angle sensor signal when the rotation direction of the electric motor is switched from the forward clockwise direction to the counterclockwise direction in the rollback suppression control device. Normally, with the shift position in the reverse range of “R”, the rotor of the electric motor rotates in CW (forward clockwise direction), while the shift position is in the forward range of “D”, “1”, etc. Thus, the rotor of the electric motor rotates in CCW (counterclockwise direction). In the rotation direction of CW in the figure, the value of the rotation angle sensor 66 (FIG. 3) decreases from the set value to 0, and when it reaches 0, returns to the set value and decreases again from the set value to 0. Repeat operation.

  On the other hand, in the CCW rotation direction of the figure, the value of the rotation angle sensor 66 (FIG. 3) increases from 0 to the set value, and when this set value is reached, returns to 0 and increases from 0 to the set value again. Repeat the operation. For example, in this example, when the rotor of the electric motor is switched from CW to CCW, the switching is performed when the value of the rotation angle sensor 66 (FIG. 3) is zero. The value at this time is maintained for a predetermined time at the time of switching. The rotational speed of the electric motor in the rotational direction of the CW before switching to CCW is set slower than the previous rotational speed.

FIG. 14 is a flowchart of an interrupt function for detecting a rollback state in this electric vehicle. This interrupt function is executed by the shift ECU 61 (FIG. 3). For example, this processing is started under the condition that the vehicle power is turned on, and the sum th_sum of the values of the rotation angle sensors calculated by the inverter device is transmitted to the speed change ECU via CAN communication.
Step 1: First, the transmission ECU reads the sum th_sum of the values of the rotation angle sensor sent from the CAN communication (S1a). Here, the th_sum signal is a processed signal of the A part and the B part shown in FIG. Next, an increase d_th_sum of th_sum is calculated (S1b). Formula: d_th_sum = th_sum-old_th_sum This increase in th_sum d_th_sum is temporarily recorded in the memory of the transmission ECU (S1c). Thereafter, the process proceeds to step 2.

Step 2:
Judgment formula: d_th_sum> 0? (S2a)
YES: The rotation direction of the electric motor is set to dir = CCW (S2b). Move to step 3a.
NO: The rotation direction of the electric motor is set to dir = CW (S2c). Move to step 3b.
Step 3:
Determine the lever operating range (branches (1), (2)).

Branch (1):
It is determined whether the current shift position is the drive range, the 2nd speed range or the 1st speed range.
Judgment formula: Currently D or 2 or 1 range? (S3a)
YES: Return.
NO: It is determined whether or not the current shift position is in the R range (S3aa).
If it is determined that the current range is the R range (S3aa; YES), the rollback state detecting means of the speed change ECU detects that the rollback state is in the reverse range (S3ab). Next, the rollback suppression control means implements rollback suppression control (control at time t1 in FIG. 15) described later (S3ac). Thereafter, this process is terminated. If it is determined in step 3aa that the current range is not the R range (S3aa; NO), the process returns.

Branch (2):
It is determined whether the current shift position is the drive range, the 2nd speed range or the 1st speed range.
Judgment formula: Currently D or 2 or 1 range? (S3b)
Here, when it is determined that the current range is the drive range, the second speed range, or the first speed range (S3b; YES), the rollback state detection means of the transmission ECU detects that the rollback state is in the forward range (S3ba). ). Next, the rollback suppression control means performs rollback suppression control (control at time t1 in FIG. 15) described later (S3bb). Thereafter, this process is terminated.
If it is determined in step 3b that the current position is not the forward range (S3b; NO), the process returns.

FIG. 15 is a time chart of the rollback that occurs in the electric vehicle in a state where the shift position is in the forward range such as “D”, “1”, and the like.
Outline of the time chart;
Between t0 and t1: The shift position is in the forward range such as the drive range, the second speed range, or the first speed range.
Vehicle speed: 0km / h
Rotation angle signal waveform: The electric motor is in a stopped state, and the output signal of the rotation angle sensor remains at a constant potential.
Brake state: Brake ON state (Brake pedal depressed state <half open or full open>
Accelerator state: Accelerator OFF state (state where accelerator pedal is not depressed)
Creep control state: The electric motor outputs a constant torque value during the creep control operation.

Between t1 and t2: In a rollback state, the vehicle speed is between 0 km / h and the maximum rollback speed.
t1: The brake is removed, that is, the brake is changed from the ON state to the OFF state.
Vehicle speed: The vehicle is slowly moving backward.
Rotation angle signal waveform: The rotor of the electric motor is gradually rotating in CW (forward clockwise direction). This is a repetitive operation in which the value of the rotation angle sensor decreases from the set value to 0, reaches 0, and then returns to the set value and decreases from the set value to 0 again.
Creep control state: During the creep control operation, the torque T of the electric motor is calculated by the following equation.
T = drive creep threshold + f (Δth_sum)
In the above equation, (Δth_sum) is an increase in the value of the rotation angle sensor. However, Δth_sum <0. f (Δth_sum): The function value (torque) changes according to the increase in the value of the rotation angle sensor (it is assumed to be a linear function).
The greater the absolute value of the increase in the value of the rotation angle sensor, the greater the torque generated by the electric motor. On the other hand, the smaller the absolute value of the increase in the value of the rotation angle sensor, the smaller the torque generated by the electric motor.

Between t2 and t3: The vehicle speed is between the maximum rollback speed and 0 km / h.
This is the same as the operation in the t1 → t2 process.

Between t3 and t4: t3: When the vehicle speed is 0 km / h, t4: When the accelerator pedal is depressed The vehicle speed is gradually accelerated from 0 km / h while the accelerator pedal is depressed.
Vehicle speed: The vehicle gradually accelerates from 0 km / h.
Rotational angle signal waveform: The rotor of the electric motor starts to rotate gradually in CCW (counterclockwise direction) from t3.
Brake state: Brake off state (fully closed)
Accelerator state: Accelerator ON state (depressing the accelerator pedal)
Creep control state: The electric motor outputs a constant torque value during creep control.

Between t4 and t5:
Vehicle speed: The vehicle gradually accelerates from 0 km / h.
Rotation angle signal waveform: The rotor of the electric motor is rotating in CCW (counterclockwise direction).
Brake state: Brake off state (fully closed)
Accelerator state: Accelerator ON state (depressing the accelerator pedal)
Creep control state: During the creep control operation, the electric motor outputs a constant torque value (the imaginary line portion is an accelerator signal).
t5 →: An accelerator signal is introduced to control the electric motor.

The effect will be described.
According to the rollback suppression control device 64 described above, the rollback state detection means 65 determines the rollback state of the vehicle from the rotation angle detected by the rotation angle sensor 66 and the shift position detected by the lever position sensor 93a. To detect. The rollback suppression control means 67 controls the torque of the electric motor 3 so that the rollback of the vehicle is suppressed when the rollback state detection means 65 detects that the vehicle is in a rollback state. The torque of the electric motor 3 is controlled according to the increase in the value of the rotation angle sensor 66. In this case, the electric motor 3 is not controlled according to the vehicle speed as in the prior art, but the torque of the electric motor 3 is controlled according to the increase in the value of the rotation angle sensor 66, so that the responsiveness of the electric motor 3 decreases. The problem can be resolved more reliably. By suppressing the rollback of the vehicle in this way, the responsiveness of the electric motor 3 can be improved and the vehicle can easily escape from the rollback state. Further, for example, by performing control to gradually increase the torque of the electric motor 3 in accordance with an increase in the value of the rotation angle sensor 66, it is possible to reduce shock torque and noise caused by the transmission 5. Become.

  The rollback suppression control means 67 increases the torque of the electric motor 3 as the increase in the rotation angle detected by the rotation angle sensor 66 is larger, and increases the torque of the electric motor 3 as the increase in the rotation angle is smaller. It is also possible to reduce the size. Thus, by changing the torque of the electric motor 3 finely according to the increase in the rotation angle, the responsiveness of the electric motor 3 can be improved reliably, and it is easier to escape from the rollback state more reliably. it can.

When the rollback suppression control means 67 switches the rotation direction of the electric motor 3 and keeps the torque of the electric motor 3 constant, the creep control is performed so as to escape from the rollback state and not to enter the rollback state again. State.
After the rollback suppression control means 67 switches the rotation direction of the electric motor 3, when the accelerator signal command exceeds a predetermined value, the electric motor 3 is controlled with the accelerator signal command. Can be controlled.

1 ... Front wheels
2 ... Rear wheel
3 ... Electric motor 65 ... Rollback state detection means 66 ... Rotation angle sensor 67 ... Rollback suppression control means 93a ... Lever position sensor (shift position detection sensor)

Claims (7)

In an electric vehicle in which wheels are driven by an electric motor, a rollback suppression control device that suppresses rollback in which the vehicle moves in the direction opposite to the traveling direction when starting,
A rotation angle sensor for detecting a rotation angle of the electric motor;
A shift position detection sensor for detecting the shift position of the vehicle;
A rollback state detection means for detecting a rollback state of the vehicle from a rotation angle detected by the rotation angle sensor and a shift position detected by the shift position detection sensor;
A rollback suppression control device for an electric vehicle, comprising: a rollback suppression control unit that suppresses rollback of the vehicle when the vehicle is detected to be in a rollback state by the rollback state detection unit.   The rollback suppression control device for an electric vehicle according to claim 1, wherein the rollback suppression control unit controls the torque of the electric motor according to a rotation angle of the rotation angle sensor in a rollback state of the vehicle. Electric vehicle rollback suppression control device.   3. The rollback suppression control device for an electric vehicle according to claim 2, wherein the rollback suppression control means is determined from a rotation angle detected by the rotation angle sensor in a rollback state of the vehicle, from the rotation angle. The electric motor torque is increased as the increase in the rotation angle obtained by subtracting the rotation angle before the predetermined time is increased, and the torque of the electric motor is decreased as the increase in the rotation angle is decreased. Rollback suppression control device.   The rollback suppression control device for an electric vehicle according to any one of claims 1 to 3, wherein the rollback suppression control unit switches the rotation direction of the electric motor from a counterclockwise direction to a forward clockwise direction. An electric vehicle rollback suppression control device for keeping the torque of the electric motor constant.   The rollback suppression control device for an electric vehicle according to any one of claims 1 to 4, wherein the rollback suppression control unit switches the rotation direction of the electric motor from a counterclockwise direction to a forward clockwise direction. A rollback suppression control device for an electric vehicle that controls the electric motor according to an accelerator signal command when the accelerator signal command exceeds a predetermined value.   The rollback suppression control device for an electric vehicle according to any one of claims 1 to 5, wherein the electric vehicle is an electric vehicle that drives either one or both of front and rear wheels of the vehicle with the electric motor. Rollback suppression control device.   The rollback suppression control device for an electric vehicle according to any one of claims 1 to 5, wherein the electric vehicle drives one of the front and rear wheels of the vehicle with an engine, and A rollback suppression control device for an electric vehicle in which the other is driven by the electric motor.

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