JP6531620B2 - Control method of electric vehicle and control device - Google Patents

Description

  The present invention relates to a control method and a control device of an electric vehicle.

  Conventionally, a regenerative brake control device for an electric car is known which is provided with setting means capable of arbitrarily setting the regenerative braking force of the motor and performs regeneration of the motor with the regenerative braking force set by the setting means (see Patent Document 1) ).

JP, 2011-172323, A

  However, when the regenerative braking force set by the setting means is large, the technique disclosed in Patent Document 1 reduces the speed of the electric vehicle when the electric vehicle is decelerated by the set regenerative braking force. There is a problem that vibration (acceleration vibration) occurs in the front-rear direction of the

  To address this problem, the inventors of the present invention adjust the motor torque as the motor rotational speed decreases, using the vehicle model constructed based on the transfer characteristic from the motor torque to the motor rotational speed, and the resistance becomes approximately a gradient resistance. It is considered to execute stop control to converge to the disturbance torque estimated value. As a result, regardless of the flat road, the uphill road, or the downhill road, it is considered to realize smooth deceleration without acceleration vibration immediately before stopping, and to maintain the stopped state.

  By the way, in a scene where the regenerative power is limited when the battery is fully charged, and in a scene where braking is performed by the driver's operation of the brake pedal, it is necessary to give the vehicle a friction braking force by a friction brake to satisfy the braking force intended by the driver. There is. The friction braking force acts on the motor torque as a resistance component not related to the gradient disturbance, so that when the friction brake is released, the motor torque can be used to hold the stopped state of the vehicle. It is necessary to correct the disturbance torque estimated value in accordance with the magnitude (frictional braking amount) to match the disturbance torque estimated value with the gradient disturbance.

  However, since the friction braking amount used when correcting the disturbance torque estimated value is estimated from the brake braking amount command value or the brake fluid pressure sensor value corresponding to the depression amount of the brake pedal, the friction coefficient of the brake pad (μ Due to the influence of the change or the variation, etc., a deviation may occur between the estimated friction braking amount and the braking amount actually applied to the vehicle. Then, the disturbance torque estimated value corrected according to the friction braking amount does not match the slope resistance, and for example, even on a flat road, it is mispredicted as an uphill road or a downhill road, and the friction brake is released. At the same time, there is a problem that the vehicle moves forward or backward and can not hold the stopped state.

  According to the present invention, during stop control, even if a deviation occurs between the estimated amount of friction braking and the amount of friction braking actually acting on the vehicle due to the influence of change or variation of the friction coefficient μ of the brake pad, An object of the present invention is to provide a technique capable of suppressing forward or backward movement of a vehicle when a friction brake is released, and holding a stopped state.

  A control method of an electric vehicle according to the present invention is a control method of an electric vehicle including a motor that functions as a traveling drive source and that applies regenerative braking force to the vehicle, and a friction braking unit that applies friction braking force to the vehicle. The rotational speed of the motor is detected, the disturbance torque acting on the motor is estimated, the amount of friction braking by the friction braking unit is detected or estimated based on the vehicle state, and the disturbance torque is corrected according to the amount of friction braking. Then, when the electric vehicle comes to a stop, the torque control at the stop is performed to control the motor so that the motor torque converges to the estimated value of the disturbance torque with the decrease of the rotational speed of the motor. When the amount of braking is larger than a predetermined value set in advance, the torque control at the time of stop is stopped, and the torque control based on the driving force characteristic calculated according to the accelerator opening degree and the rotational speed of the motor is executed.

  According to the present invention, the stop control is stopped according to the friction braking amount, and the torque control according to the driver's intention based on the driving force characteristic calculated according to the accelerator opening degree and the rotational speed of the motor is performed. . Thus, even if there is a deviation between the estimated friction braking amount and the friction braking amount actually applied to the vehicle, it is possible to maintain the stopped state when the friction brake is released.

FIG. 1 is a block diagram showing a main configuration of an electric vehicle provided with a control device of an electric vehicle according to one embodiment. FIG. 2 is a flow chart showing a flow of processing of motor current control performed by the motor controller. FIG. 3 is a diagram showing an example of a first accelerator opening degree-torque table. FIG. 4 is a view showing an example of a second accelerator opening degree-torque table. FIG. 5 is a diagram showing an example of a third accelerator opening degree-torque table. FIG. 6 is a diagram for explaining torque switching that is executed based on the result of the stop control cancellation determination process in the stop control cancellation determination process. FIG. 7 is a flowchart showing a flow of stop control cancellation determination processing. FIG. 8 is a diagram modeling a driving force transmission system of a vehicle. FIG. 9 is a block diagram for realizing the stop control process. FIG. 10 is a diagram for explaining a method of calculating the motor rotation speed F / B torque based on the motor rotation speed. FIG. 11 is a block diagram for realizing calculation of a disturbance torque estimated value by the disturbance torque estimator. FIG. 12 is a block diagram for explaining the damping control process. FIG. 13 is a view for explaining control results by the control device for the electrically powered vehicle in the embodiment. FIG. 14 is a diagram for describing control results by the control device for the electrically powered vehicle in the embodiment. FIG. 15 is a view for explaining control results by the control device for the electrically powered vehicle in the embodiment.

  In the following, an example in which the control device for an electric vehicle according to the present invention is applied to an electric vehicle having a motor as a drive source will be described.

  FIG. 1 is a block diagram showing a main configuration of an electric vehicle provided with a control device of an electric vehicle according to an embodiment. In particular, the control device for a vehicle in the present embodiment can be applied to a vehicle that can control acceleration / deceleration or stop of the vehicle only by operating the accelerator pedal. In this vehicle, the driver depresses the accelerator pedal at the time of acceleration, and reduces the depression amount of the accelerator pedal being depressed or reduces the depression amount of the accelerator pedal to zero at the time of deceleration or stop. In addition, on an uphill road, in order to prevent the backward movement of the vehicle, the vehicle may approach a stop while depressing the accelerator pedal.

  Signals indicating vehicle states such as vehicle speed V, accelerator opening AP, rotor phase α of motor (three-phase AC motor) 4 and currents iu, iv, iw of motor 4 are input as digital signals to motor controller 2 Ru. The motor controller 2 generates a PWM signal for controlling the motor 4 based on the input signal. Further, the motor controller 2 generates a drive signal of the inverter 3 in accordance with the generated PWM signal. The motor controller 2 further generates a friction braking amount command value by a method described later.

  The inverter 3 converts direct current supplied from the battery 1 into alternating current by turning on / off two switching elements (for example, power semiconductor elements such as IGBTs and MOS-FETs) provided for each phase. And supply a desired current to the motor 4.

  The motor 4 generates a driving force by the alternating current supplied from the inverter 3 and transmits the driving force to the left and right driving wheels 9 a and 9 b via the reduction gear 5 and the drive shaft 8. The motor 4 recovers the kinetic energy of the vehicle as electrical energy by generating regenerative driving force when the motor 4 is rotated by the drive wheels 9a and 9b when the vehicle is traveling. In this case, the inverter 3 converts an alternating current generated during regenerative operation of the motor 4 into a direct current, and supplies the direct current to the battery 1.

  The current sensor 7 detects three-phase alternating current iu, iv, iw flowing in the motor 4. However, since the sum of the three-phase alternating current iu, iv, iw is 0, any two-phase current may be detected, and the remaining one-phase current may be calculated.

  The rotation sensor 6 is, for example, a resolver or an encoder, and detects a rotor phase α of the motor 4.

  The fluid pressure sensor 10 detects the brake fluid pressure of the friction brake 12.

  The brake controller 11 generates a brake fluid pressure corresponding to the friction braking amount command value generated by the motor controller 2. The brake controller 11 also performs feedback control so that the brake fluid pressure detected by the fluid pressure sensor 10 follows a value determined according to the friction braking amount command value.

  The friction brake 12 functions as a friction braking unit. Specifically, the friction brake 12 is provided on the left and right drive wheels 9a and 9b, and presses a brake pad against the brake rotor according to the brake fluid pressure to generate a braking force on the vehicle. In the following description, the magnitude of the braking force is referred to as a braking force.

  FIG. 2 is a flowchart showing a flow of processing of motor current control performed by the motor controller 2.

In step S201, a signal indicating a vehicle state is input to the motor controller 2. Here, the vehicle speed V (m / s), the accelerator opening θ (%), the rotor phase α (rad) of the motor 4, the rotational speed Nm (rpm) of the motor 4, the three-phase alternating current iu flowing in the motor 4 iv, iw, a DC voltage value V _dc (V) between the battery 1 and the inverter 3, a brake braking amount estimated value B, and a brake pedal SW are input.

  The vehicle speed V (m / s) is a wheel (braking wheel) that transmits a braking force, or a wheel speed of a wheel (driving wheels 9a and 9b) that transmits a driving force when the vehicle is driven. The vehicle speed V is obtained by communication from a not-shown vehicle speed sensor or another controller. Alternatively, the vehicle speed V (km / h) can be obtained by multiplying the rotor mechanical angular velocity ωm by the tire moving radius r and dividing by the gear ratio of the final gear.

  The accelerator opening degree θ (%) is acquired from an accelerator opening degree sensor (not shown) or acquired from other controllers such as a vehicle controller (not shown) by communication.

  The rotor phase α (rad) of the motor 4 is obtained from the rotation sensor 6. The rotational speed Nm (rpm) of the motor 4 is obtained by dividing the rotor angular velocity ω (electrical angle) by the number of pole pairs p of the motor 4 to obtain the motor rotational speed ωm (rad / s) which is the mechanical angular velocity of the motor 4 The value is obtained by multiplying 60 / (2π) by the obtained motor rotational speed ωm. The rotor angular velocity ω is obtained by differentiating the rotor phase α.

  The currents iu, iv, iw (A) flowing through the motor 4 are obtained from the current sensor 7.

The DC voltage value V _dc (V) is obtained from a power supply voltage value transmitted from a voltage sensor (not shown) provided on a DC power supply line between the battery 1 and the inverter 3 or a battery controller (not shown).

  The brake braking amount estimated value B is acquired from the brake fluid pressure sensor value detected by the fluid pressure sensor 10. Alternatively, a detected value by a stroke sensor (not shown) or the like that detects the depression amount of the brake pedal by the driver's pedal operation may be used. Alternatively, the friction braking amount command value generated by the motor controller 2 or another controller may be obtained through communication or the like, and the obtained friction braking amount command value may be used as the brake braking amount estimated value B.

  The brake pedal SW is a switch signal for determining whether or not the driver has performed a brake operation, and is acquired from a brake switch (not shown) attached to the brake pedal. When the brake pedal SW = 1, it indicates that the driver operates the brake pedal, and when the brake pedal SW = 0, it indicates that the brake pedal is not operated.

In the torque target value calculation process of step S202, the motor controller 2 sets a first torque target value Tm1 ^* . Specifically, reference is made to a first accelerator opening degree-torque table shown in FIG. 3 showing one aspect of the driving force characteristic calculated according to the accelerator opening degree θ and the motor rotational speed ωm inputted in step S201. By doing this, the first torque target value Tm1 ^* is set.

However, when it is determined that the stop control is to be stopped in the stop control stop determination process of step S203 described later, the motor controller 2 is in the region where the accelerator opening is smaller than the first accelerator opening-torque table. The fourth torque target value Tm4 ^* as the torque target value is set by referring to the second accelerator opening degree-torque table shown in FIG. 4 set so as to reduce the regenerative braking amount. Note that the third accelerator opening degree-torque shown in FIG. 5 that outputs a so-called creep torque where the torque target value [Nm] at an accelerator opening degree 0 [%] and the motor rotational speed 0 [rpm] becomes a positive torque The fourth torque target value Tm4 ^* may be set by referring to the table.

  In the stop control stop determination process of step S203, the differential process is performed on the vehicle speed V [m / s] corresponding to the motor rotational speed and the wheel speed, and the slip state of the tire is estimated based on the value obtained by the differential process. . If the value obtained by differentiating the vehicle speed V [m / s] is equal to or greater than a predetermined value, it is determined that the tire is in a slip state, and the stop control stop determination flag flg_stop is set to 1.

  Further, the stop control stop determination flag flg_stop is set to 1 also when the brake pedal SW is 1, that is, the brake operation is performed by the driver. Details of the stop control cancellation determination process executed in this step will be described later.

In step S204, the controller 2 performs stop control processing. Specifically, the controller 2 determines whether or not it is just before stopping, and when it is not just before stopping, the first torque target value Tm1 ^* calculated in step S202 is set to the third motor torque command value Tm3 ^* When the vehicle is about to stop, the second torque target value Tm2 ^* is set to the third motor torque command value Tm3 ^* . The second torque target value Tm2 ^* converges to the disturbance torque command value Td as the motor rotational speed decreases, and is positive torque on an uphill road, negative torque on a downhill road, and substantially zero on a flat road. Thereby, it is possible to maintain the stopped state regardless of the slope of the road surface.

Furthermore, the third motor torque command value Tm3 ^* is switched as shown in FIG. 6 in accordance with the stop control stop determination flag flg_stop determined in step 203 described above, and the final torque target value (torque target value It is set to a fifth torque target value Tm5 ^* as Tm ^* ).

FIG. 6 is a diagram for explaining torque switching that is executed based on the result of the stop control cancellation determination process in the stop control cancellation determination process. As shown in FIG., The third torque target value Tm3 ^*, when the flg_stop = 0 (not stop the stop control) is set to the fifth torque target value Tm5 ^*. flg_stop = 1 when (to stop the stop control) is the fourth torque target value Tm4 ^* is calculated by the processing in step S202, it is set to the fifth torque target value Tm5 ^*. Details of the stop control process will be described later.

In step S205, the motor controller 2 performs damping control processing. Specifically, the motor controller 2 performs damping control processing to a fifth torque target value Tm5 ^* and the motor rotation speed ωm as torque target value Tm ^*. As a result, the torque target value Tm ^* suppresses torque transmission system vibration (such as torsional vibration of the drive shaft) without sacrificing the response of the drive shaft torque. Details of the damping control process will be described later.

In the following step S206, the controller 2 performs current command value calculation processing. Specifically, in addition to the torque target value Tm ^* calculated in step S205, the d-axis current target value id ^* and the q-axis current target value iq ^* are obtained based on the motor rotation speed ωm and the DC voltage value Vdc. For example, a table in which the relationship between the torque command value, the motor rotational speed, and the DC voltage value, and the d-axis current target value and the q-axis current target value is defined in advance is prepared by referring to this table. The d-axis current target value id ^* and the q-axis current target value iq ^* are obtained.

In step S207, current control is performed to match the d-axis current id and the q-axis current iq with the d-axis current target value id ^* and the q-axis current target value iq ^* obtained in step S206, respectively. Therefore, first, the d-axis current id and the q-axis current iq are obtained based on the three-phase alternating current values iu, iv, iw input in step S201 and the rotor phase α of the electric motor 4. Subsequently, the d-axis and q-axis voltage command values vd and vq are calculated from the deviation between the d-axis and q-axis current command values id ^* and iq ^* and the d-axis and q-axis currents id and iq.

Then, from the d-axis and q-axis voltage command values vd and vq and the rotor phase α of the electric motor 4, three-phase AC voltage command values vu, vv and vw are obtained. The PWM signals tu (%), tv (%) and tw (%) are obtained from the three-phase AC voltage command values vu, vv, vw and the current voltage value Vdc. The electric motor 4 can be driven at a desired torque indicated by the target torque value Tm ^* by opening and closing the switching elements of the inverter 3 by the PWM signals tu, tv, tw thus obtained.

<Stop control cancellation judgment processing>
Here, the details of the stop control cancellation determination process executed in the above-described step S203, which is characteristic of the present invention, will be described with reference to the flowchart shown in FIG.

FIG. 7 is a flowchart showing stop control cancellation determination processing. The stop control cancellation determination process is constantly executed in a fixed cycle in the motor controller 2 and it is determined whether or not to stop the stop control executed in step S204. If it is determined that the to cancel the stop control, in the stop control process, as described above with reference to FIG. 6, the fourth torque target value Tm4 ^* is set to the fifth torque target value Tm5 ^*. Then, if it is determined that the stop control is to be canceled in the present process, and it is determined that the stop control is to be continued (is not to be canceled) at the time of the previous process, the third torque target value Tm 3 ^* Is set to the fifth torque target value Tm5 ^* .

  In the slip determination process described below, the various control parameters used in the stop control process according to step S204 in FIG. 2 are quicker responsive than the control parameters (normal control parameters) normally used in the stop control. The control parameter at the time of resumption of the stop control is set, and the set control parameter at the time of resumption of the stop control is continued until a predetermined time T1 elapses. Thereafter, after the stop control stop determination process executed in step S203 and the stop control are stopped, the control parameter at the time of restart of the stop control which is set when restarting the stop control is continued for a predetermined time T1. The processing for this will be described based on the flow.

  In step S701, the motor controller 2 determines whether the estimated braking amount B is larger than a predetermined value. In the present embodiment, in order to set the predetermined value to 0, the motor controller 2 determines whether the brake braking amount estimated value B is 0 or not. That is, when the brake braking amount estimated value B is 0 and no resistance component not related to the gradient acts on the vehicle, the process of step S704 is performed. If the brake braking amount estimated value B is not zero and a resistance component not related to the gradient acts on the vehicle, the process of step S702 is performed. The predetermined value to be compared with the estimated value B of the braking amount in this step is appropriately set according to the allowable amount of the estimation error of the disturbance torque caused by the change of the friction coefficient μ of the brake pad.

  In step S702, the motor controller 2 calculates the motor rotational acceleration represented by the absolute value of the value obtained by differentiating the motor rotational speed ωm, that is, the absolute value of the difference between the previous value ωm_z of the motor rotational speed and the current value ωm of the motor rotational speed. Calculate | dω / dt |. Then, the motor rotational acceleration | dω / dt | is compared with the motor rotational acceleration slip1 [rad / s ^ 2] which can be determined that the driving wheel of the vehicle is in a slip state, and | dω / dt | <slip1 holds. If so, it is determined that the vehicle is not in a slip state, and the process of step S703 is executed. If | dω / dt | ≧ slip1 holds, it is determined that the vehicle is in a slip state, and the process of step S705 is performed. In addition, the motor rotational acceleration which can be determined that the driving wheel of the vehicle is in a slip state has a value greater than the amount of change based on the deceleration of the vehicle which can usually be assumed and the change of the road surface gradient.

  In step S703, the motor controller 2 determines whether the brake pedal SW is 0 (OFF) or 1 (ON). When it is determined that the brake pedal SW is 0 and there is no request for stopping the vehicle by at least the brake pedal operation by the driver, the process of step S704 is performed. If it is determined that the brake pedal SW is 1 and there is a vehicle stop request due to the driver's brake pedal operation, the process of step S704 is performed.

  In step S704, the motor controller 2 determines that the resistance not related to the gradient does not act on the vehicle by the processing in steps S701 to S703, and that the resistance not related to the gradient acts on the vehicle. If it is determined that the wheels are not in a slip state, and it is determined that there is no vehicle stop request by the driver's brake operation, it is determined that the stop control is to be continued, and the stop control is determined Process flg_stop is set to 0. After setting, the process of step S706 is performed.

  In step S705, the motor controller 2 determines that the resistance not related to the gradient acts on the vehicle by the processing in steps S701 to S703, and the wheel is in a slip state, or the driver's brake When it is determined that there is a vehicle stop request by operation, it is determined that the stop control is to be stopped, and the stop control stop determination process flg_stop is set to 1. After setting, the process of step S706 is performed.

  In step S706, the motor controller 2 determines whether the stop control stop determination flag flg_stop has changed from 0 (stop control continued) to 1 (stop control stop) in comparison with the previous process. That is, when the previous value flg_stop_z of the stop control cancellation determination flag is 0 and the stop control cancellation determination flag flg_stop in this processing is 1, the processing of the following step S707 is executed, and in the other cases, step S708. Processing is performed.

  In step S 707, the motor controller 2 holds the previous value of the disturbance torque estimated value. Specifically, the previous value Td_z of the disturbance torque estimated value is stored as a disturbance torque estimated value Td_hold in a storage circuit such as a memory or a register. After storing, the processing of the subsequent step S711 is executed.

  In step S708, the motor controller 2 determines whether or not the stop control cancellation determination flag flg_stop has changed from 1 (stop control cancellation) to 0 (stop control continuation) in comparison with the previous processing. That is, when the previous value flg_stop_z of the stop control cancellation determination flag is 1 and the stop control cancellation determination flag flg_stop in this processing is 0, the processing of the following step S709 is executed, and otherwise step S710. Processing is performed.

  In step S709, the motor controller 2 sets a predetermined timer time T1 in the timer 1. The timer 1 is a timer for measuring the timing of returning the control parameter to the normal control parameter from the control parameter at the time of stop control resumption set in the process of step S713 described later. After the timer time T1 is set to the timer 1, the process of step S712 for performing the countdown process of the timer 1 is executed.

  In step S710, the motor controller 2 determines whether the count value of the timer 1 is zero. When the timer 1 is 0, it is the timing to return the control parameter of the stop control process from the control parameter at the time of stop control resumption to the control parameter at the normal time, the process of the subsequent step S711 is executed. If the timer 1 is not 0, the process of step S 712 is performed to count down the timer 1.

  In step S711, the motor controller 2 sets a control parameter at the normal time as a control parameter used for the stop control process, and ends the present process.

  In step S 712, the motor controller 2 subtracts 1 from the count value of the timer 1 and stores the result in the timer 1 again, thereby performing a process of counting down the timer 1 for each operation cycle. After the timer 1 is counted down, the process of the subsequent step S713 is performed.

  In step S713, the motor controller 2 sets a parameter at the time of stop control resumption as a control parameter used for the stop control processing, and ends this processing. The parameter at the time of resumption of the stop control is a control parameter which is more responsive to the control parameter at the normal time as described above, and is set by performing the following three processes for the control parameter at the normal time.

  That is, (1) In the multiplier 601 of FIG. 10, the gain Kvref, which is multiplied by the motor rotational speed ωm when calculating the motor rotational speed feedback torque Tω, is set to a value larger than normal. (2) A denominator in a filter (refer to equation (13)) constituted by a numerator of a quadratic equation of Hz (s) and a denominator of the quadratic equation shown in a control block 805 of FIG. The attenuation coefficient ζ c of is set to a value smaller than that at the normal time. (3) The time constant of the low-pass filter H (s) indicated by the control block 802 in FIG. 11 is set to a value smaller than that at the normal time. As a result, the parameter at the start of the stop control with increased responsiveness is set.

<Stop control processing>
First, the transfer characteristic G _p (s) from the motor torque Tm to the motor rotational speed ωm in the control device for an electrically powered vehicle in the present embodiment will be described. The transfer characteristic Gp (s) is used as a vehicle model obtained by modeling a driving force transfer system of the vehicle in the stop control process including the estimation of the disturbance torque.

FIG. 8 is a diagram modeling a driving force transmission system of a vehicle, and each parameter in the figure is as shown below.
J _m : Inertia of electric motor J _w : Inertia of driving wheel M: Weight of vehicle K _d : Torsional rigidity of driving system K _t : Coefficient relating to friction between tire and road surface N: Overall gear ratio r: Load radius of tire ω _m : Motor rotational speed T _m : Torque target value Tm ^*
T _d : torque of driving wheel F: force applied to vehicle V: speed of vehicle ω _w : angular velocity of driving wheel T _b : friction braking amount (motor shaft conversion torque) (≧ 0)
And from FIG. 8, the following equation of motion can be derived.

However, the asterisk ( ^* ) attached to the upper right of the sign in Formulas (1) to (3) represents a time derivative.

  The transfer characteristic Gp (s) from the torque target value Tm of the motor 4 to the motor rotational speed ωm is obtained based on the equation of motion shown by the equations (1) to (5), and is represented by the following equation (6).

  However, each parameter in Formula (6) is represented by following Formula (7).

  If the poles and zeros of the transfer function shown in equation (6) are examined, it can be approximated to the transfer function of the following equation (8), and one pole and one zero indicate extremely close values. This corresponds to the fact that α and β in the following equation (8) show extremely close values.

  Therefore, Gp (s) is a (second-order) / (third-order) transmission as shown in the following equation (9) by performing pole-zero cancellation (approximating as α = β) in equation (8) Configure the characteristics.

  When the damping control (feed-forward compensator) in step S205 is used in combination, the vehicle model Gp (s) is controlled as shown by the following equation (10) according to Gp (s) and the damping control algorithm. It can be regarded as a vehicle response Gr (s) when vibration control is applied.

  Note that the vibration suppression control (F / F compensator) may be vibration suppression control described in JP-A-2001-45613, or vibration suppression control described in JP-A-2002-152916. It is good.

  Subsequently, the details of the stop control process will be described with reference to FIGS.

  FIG. 9 is a block diagram for realizing the stop control process. The stop control process is performed using the motor rotational speed F / B torque setting unit 501, the disturbance torque estimator 502, the adder 503, and the torque comparator 504. The details of each configuration will be described below.

  The motor rotation speed F / B torque setting unit 501 calculates a motor rotation speed feedback torque (hereinafter referred to as a motor rotation speed F / B torque) Tω based on the detected motor rotation speed ωm. The details will be described with reference to FIG.

  FIG. 10 is a diagram for describing a method of calculating the motor rotation speed F / B torque Tω based on the motor rotation speed ωm. The motor rotational speed F / B torque setting unit 501 includes a multiplier 601, and calculates the motor rotational speed F / B torque Tω by multiplying the motor rotational speed ωm by the gain Kvref. However, Kvref is a negative (minus) value required to stop the electric vehicle immediately before the stop of the electric vehicle, and is appropriately set, for example, by experimental data or the like. The motor rotation speed F / B torque Tω is set as a torque at which a larger braking force can be obtained as the motor rotation speed ωm is larger.

  The motor rotation speed F / B torque setting unit 501 is described as calculating the motor rotation speed F / B torque Tω by multiplying the motor rotation speed ωm by the gain Kvref, but the regenerative torque for the motor rotation speed ωm The motor rotation speed F / B torque Tω may be calculated using a regenerative torque table that defines the above, an attenuation rate table in which the attenuation rate of the motor rotation speed ωm is stored in advance, or the like.

Returning to FIG. 9, the description will be continued. The disturbance torque estimator 502 calculates a disturbance torque estimated value _Td based on the detected motor rotational speed ωm and the third torque target value Tm3 ^* . However, when the previous value flg_stop_z of the stop control stop determination flag is 1 and the stop control stop determination flag flg_stop during this processing is 0, the disturbance torque that holds the disturbance torque estimated value _Td in the stop control stop determination processing Each filter processing in the disturbance torque estimator 502 is initialized to match the estimated value Td_hold. The details of the disturbance torque estimator 502 will be described with reference to FIG.

FIG. 11 shows disturbance torque estimated value T based on motor rotational speed ωm, fifth torque target value Tm5 ^*, and brake torque estimated value calculated based on friction brake braking amount estimated value B and vehicle speed V. It is a block diagram for demonstrating the method to calculate _d . The disturbance torque estimator 502 includes a control block 801, a control block 802, a brake torque estimator 803, a subtractor 804, and a control block 805.

  The control block 801 has a function as a filter having a transfer characteristic of H (s) / Gr (s), and performs the filtering process on the motor rotational speed ωm to obtain the first motor torque estimated value. calculate. H (s) is the denominator order of the transfer characteristic Gr (s) (see equation (10)) of the motor torque Tm and the motor rotational speed ωm when the difference between the denominator order and the numerator order is applied to damping control. It is a low pass filter having a transfer characteristic that is equal to or greater than the difference between.

The control block 802 has a function as a low pass filter having a transfer characteristic of H (s), and performs the filtering process on the third torque target value Tm3 ^* to obtain the second motor torque estimated value. calculate.

  The brake torque estimator 803 calculates a brake torque estimated value based on the friction brake braking amount estimated value B and the vehicle speed V. The brake torque estimator 803 performs multiplication processing for converting the torque of the motor shaft from the estimated value of the friction brake braking amount B, response from the fluid pressure sensor value detected by the fluid pressure sensor 10 to the actual braking force, etc. The brake torque estimated value is calculated taking into consideration.

  The subtractor 804 subtracts the first motor torque estimated value and the brake torque estimated value from the second motor torque estimated value, and outputs a value obtained by subtraction to the control block 805.

  The control block 805 is a filter having a transfer characteristic of Hz (s), and performs filtering processing on the output of the subtractor 804 to calculate the disturbance torque estimated value Td.

  Here, the transfer characteristic Hz (s) will be described. Rewriting the above equation (10) gives the following equation (11). However, ζz, ωz, and ωp in equation (11) are each represented by equation (12).

  From the above, Hz (s) can be expressed by the following equation (13).

  The disturbance torque estimated value Td calculated as described above is a parameter that is estimated by a disturbance observer as shown in FIG. 11 and is a parameter that represents a disturbance that acts on the vehicle.

Here, the disturbance acting on the vehicle may be air resistance, modeling error due to fluctuation of the vehicle mass due to the number of occupants or loading amount, rolling resistance of the tire, slope resistance of the road surface, etc. The dominant disturbance factor at the start is the gradient resistance. Although the disturbance factor differs depending on the driving conditions, the disturbance torque estimator 502 is a disturbance based on the motor torque command value Tm ^* , the motor rotation speed ωm, and the vehicle model Gr (s) when damping control is applied. Since the torque estimated value Td is calculated, the above-mentioned disturbance factors can be collectively estimated. This makes it possible to achieve a smooth stop from deceleration under any operating conditions.

Returning to FIG. 9, the description will be continued. The adder 503 adds the motor rotation speed F / B torque Tω calculated by the motor rotation speed F / B torque setting unit 501 and the disturbance torque estimated value Td calculated by the disturbance torque estimator 502, A second torque target value Tm2 ^* is calculated. As the motor rotation speed ωm decreases and approaches 0, the motor rotation speed F / B torque Tω also approaches 0. Therefore, the second torque target value Tm2 ^* is a disturbance torque estimation according to the decrease of the motor rotation speed ωm. It converges to the value Td.

The torque comparator 504 compares the magnitudes of the first torque target value Tm1 ^* and the second torque target value Tm2 ^* , and sets the larger torque target value as the third torque target value Tm3 ^* . . While the vehicle is traveling, the second torque target value Tm2 ^* is smaller than the first torque target value Tm1 ^{*, and} the first torque target value Tm1 is obtained when the vehicle decelerates and the vehicle is about to stop (the vehicle speed is less than the predetermined vehicle speed). ^* Larger than. Accordingly, the torque comparator 504, if the first torque target value Tm1 ^* is the second torque target value Tm2 ^* more greater, it is determined that the stop just before the previous, the first torque target value Tm1 ^* third torque Set as a target value Tm3 ^* . In addition, when the second torque target value Tm2 ^* becomes larger than the first torque target value Tm1 ^* , the torque comparator 504 determines that the vehicle is near a stop, and the second torque target value Tm1 ^* is not selected. Of the torque target value Tm2 ^* is set as a third torque target value Tm3 ^* . In order to maintain the stopped state, the second torque target value Tm2 ^* converges to a positive torque on an uphill road, a negative torque on a downhill road, and substantially zero on a flat road.

Then, as described above with reference to FIG. 6, in the case where the stop control stop determination flag flg_stop is set to 0 (stop control continued) in the stop control stop determination process, the third torque target value Tm 3 ^* is It is set to the fifth torque target value Tm5 ^* as the final torque target value.

  The above is the details of the stop control process. By performing such processing, regardless of the gradient of the road surface on which the vehicle is traveling, the vehicle can be smoothly stopped only by the motor torque, and the stopped state can be maintained.

Vibration suppression control
Here, the details of the damping control executed in step S205 according to FIG. 2 described above will be described using FIG.

FIG. 12 is a block diagram for explaining the details of the damping control process used in the present embodiment. The feed-forward compensator 908 (hereinafter referred to as the F / F compensator) receives the vehicle response Gr (s) shown by the above equation (10), and the model Gp of the transfer characteristic of the torque input to the vehicle and the rotational speed of the motor It functions as a filter having a transfer characteristic of Gr (s) / Gp (s) composed of the inverse system of s), and performs filtering processing on the fifth torque target value Tm5 ^* . Vibration suppression control processing by feed forward compensation is performed.

  The damping control performed by the F / F compensator 908 may be damping control described in JP-A-2001-45613, or may be disclosed in JP-A-2002-152916. Vibration control may be used.

  Control blocks 903 and 904 are filters used in feedback control (hereinafter, feedback is referred to as F / B). The control block 903 is a filter having the above-described transfer characteristic Gp (s), and is obtained by adding the output of the F / F compensator 908 output from the adder 905 and the output of the control block 904 described later. Perform a filtering process on the values. Then, the motor rotational speed ωm is subtracted from the value output from the control block 903 in the subtractor 906. The subtracted value is input to control block 904. The control block 904 is H (s) / Gp (s) composed of a low pass filter H (s) and an inverse system of a model Gp (s) of the torque input to the vehicle and the transfer characteristic of the rotational speed of the motor. It is a filter having transfer characteristics, and performs filtering on the output from the subtractor 906. The filtering process is performed, and the value calculated as the F / B compensation torque is output to the gain compensator 907.

Gain compensator 907 is a filter having a gain K _FB, by adjusting the value of the gain K _FB, it is possible to adjust the stability of the F / B compensator used in damping control processing. The F / B compensation torque T _{F / B} whose gain has been adjusted by the gain compensator 907 is output to the adder 905.

Then, in the adder 905, the fifth target torque value Tm5 ^* subjected to the damping control process by the F / F compensator 908 and the value T _{F / B} calculated as the above-mentioned F / B compensation torque are added. As a result, the motor torque command value Tm ^* that suppresses the vibration of the torque transmission system of the vehicle is calculated.

  The damping control described above with reference to FIG. 12 is an example, and may be the damping control described in Japanese Patent Laid-Open No. 2003-9566, or the control described in Japanese Patent Laid-Open No. 2010-288332. Vibration control may be used.

  The above is the details of the control device of the electric vehicle according to the present embodiment. Below, in addition to the regenerative torque command of the motor 4 while the vehicle is traveling on a flat road, the control device of the electric-powered vehicle of the present embodiment is used in a scene where a brake braking amount is further applied to the vehicle The control result in the case of application to a vehicle will be described based on comparison with the conventional example with reference to FIGS. 13 to 15.

  FIG. 13 (a) shows a time chart of the control result according to the conventional example, and FIG. 13 (b) shows a time chart of the control result according to the present embodiment. FIG. 13 represents, in order from the top, the torque command value, the vehicle speed V, the longitudinal acceleration, the disturbance torque estimated value, and the brake pedal SW as an index as to whether or not the braking amount has been added. Further, a dotted line in the drawing showing a torque command value indicates a stop control stop determination flag flg_stop (0: stop control continued, 1: stop control stop).

  First, the control result according to the conventional example will be described with reference to FIG.

  At time t0, braking is performed with regenerative torque, and the disturbance torque estimated value is a value equivalent to a flat road.

  At time t1, the driver depresses the brake pedal to apply a brake braking amount to the vehicle, and the brake pedal SW becomes one.

  At time t2, the disturbance torque estimated value is corrected according to the brake braking amount estimated value B obtained by estimating the brake braking amount acting on the vehicle. However, due to the influence of μ change of the brake pad, etc., the brake braking amount actually acting on the vehicle with respect to the brake braking amount estimated value B is small, so the brake torque greater than the actual value in the subtractor 804 in the disturbance torque estimator 502 The estimated value is subtracted. As a result, the disturbance torque estimated value, which should be zero on a flat road, indicates a negative value, and it is erroneously estimated as a downhill tendency.

  From time t3 to t4, since the stop control is executed in a state where the disturbance torque estimated value is erroneously estimated in the downward slope tendency, the torque command value converges to a negative value. However, since the brake torque larger than the motor torque in the negative direction according to the torque command value acts on the vehicle by the driver's brake operation, the stopped state of the vehicle is maintained.

  At time t5, the brake braking force applied to the vehicle is released by the driver's brake pedal operation. However, since the disturbance torque estimated value is erroneously estimated as a downhill tendency, and the torque command value has a negative value, the vehicle moves backward.

  At time t6, the brake braking force is released, so the motor torque given by the stop control causes the vehicle in reverse to stop.

  Next, the control result according to the present embodiment will be described with reference to FIG.

  At time t0, braking is performed with regenerative torque, and the disturbance torque estimated value is a value equivalent to a flat road.

At time t1, the brake pedal amount is added to the vehicle by the driver's operation of the brake pedal, and the brake pedal SW becomes 1 and the stop control stop determination flag flg_stop is set to 1, so the stop control is stopped and the stop control processing is performed. The third torque target value Tm3 ^* calculated in the above is switched to the fourth torque target value Tm4 ^* .

From time t2 to t3, the vehicle is decelerated by the brake braking amount and the fourth torque target value Tm4 ^* .

  From time t3 to t4, the vehicle is stopped mainly by the amount of braking by the driver's brake pedal operation.

  At time t5, the amount of braking applied to the vehicle by the driver's operation of the brake pedal is released, and the brake pedal SW becomes zero, so the stop control cancellation determination flag flg_stop becomes zero. Therefore, as the disturbance torque estimated value, the disturbance torque estimated value Td_hold held in the process of step S707 according to FIG. 7 is set as the initial value, and the stop control based on the control parameter that cited the quick response set in step S713 To be executed.

  From time t5 to t6, since the disturbance torque estimated value indicates a flat road equivalent and matches the gradient resistance, the stopped state of the vehicle is maintained.

  Next, referring to FIG. 14, when the vehicle is decelerating by the regenerative torque of the motor 4 while traveling on a flat road, a brake braking amount is applied to the vehicle by the driver's brake pedal operation, and the road surface condition is further achieved. Control results in a scene in which the vehicle slips due to the above will be described. In the present control, the brake pedal SW signal is not detected, and it is determined based on the friction brake braking amount estimated value B and the slip state of the vehicle whether to stop the stop control.

  FIG. 14 (a) shows a time chart of control results according to the conventional example, and FIG. 14 (b) shows a time chart of control results according to the present embodiment. FIG. 14 shows a torque command value, a vehicle speed V, a slip ratio, a longitudinal acceleration, a disturbance torque estimated value, and a braking amount in order from the top. Further, a dotted line in the drawing showing a torque command value indicates a stop control stop determination flag flg_stop (0: stop control continued, 1: stop control stop). The dotted line in the figure showing the vehicle speed V shows the vehicle speed Vc.

  The road surface condition changes as follows on the time axis shown on the horizontal axis. That is, time t0 to t2 is a high μ road such as a normal asphalt road surface, time t2 to t4 is a low μ road such as an icing road, and time t4 to t6 is a high μ road.

  First, the control result according to the conventional example will be described with reference to FIG.

  At time t0, braking is performed according to the regenerative torque command, and the disturbance torque estimated value is a value equivalent to a flat road.

  At time t1, the amount of friction brake braking is added to the regenerative braking and braking is performed, so that the longitudinal acceleration is increased more to the negative side, that is, to the braking side. The disturbance torque estimated value is equivalent to a flat road according to the actual road surface condition by correcting the brake torque estimated value.

  From time t2 to time t4, the traveling road surface of the vehicle becomes a low μ road, and the vehicle slips, so the vehicle speed becomes steep and approaches a lock tendency toward zero, and then the slip condition returns to the grip condition, and the vehicle speed increases sharply By doing this, the disturbance torque estimated value moves up and down and becomes vibrational. Therefore, the torque command value (motor torque) calculated based on the disturbance torque estimated value also vibrates. As a result, since the longitudinal acceleration is shaken back and forth, the driver is given an unpleasant vibration.

  Next, the control result according to the present embodiment will be described with reference to FIG.

  At time t0, braking is performed according to the regenerative torque command, and the disturbance torque estimated value is a value equivalent to a flat road.

  At time t1, in addition to the regenerative braking, the front-rear acceleration increases to the braking side by the rising of the friction brake braking amount B, but the disturbance torque estimated value is a brake torque estimated value calculated based on the brake braking amount estimated value B It becomes equivalent to a flat road by being corrected by.

From time t2 to time t4, the road surface on which the vehicle is traveling becomes a low μ road, and the vehicle speed tends to lock rapidly approaching zero. Therefore, in addition to the friction brake braking amount B being turned on, it is determined that the vehicle is in the slip state, so the stop control stop determination flag flg_stop is set to 1 and the third calculated in the stop control processing. The torque target value Tm3 ^* of the above switches to the fourth torque target value Tm4 ^* calculated with reference to the accelerator opening degree-torque table. As a result, the stop control is stopped, and the control is switched to a control that does not cause the motor torque to converge to the disturbance torque estimated value during the stop. As a result, the vehicle is operated based on the fourth torque target value Tm4 ^* calculated according to the driver's accelerator operation, so that the slip tends to converge, and the vibration of the disturbance torque estimated value generated in the conventional example Can be suppressed and the vibration of longitudinal acceleration can be eliminated.

  From time t4 to time t5, the road surface state returns from the low μ road to the high μ road, and the slip state determination flag flg_slip is set to zero. After that, the motor torque is converged to the disturbance torque estimated value by the stop control based on the speed parameter at the start of the stop control which increases the speed responsiveness set in step S713 of FIG. It will decelerate.

  Then, at t5 to t6 after the elapse of T1 time, the vehicle is stopped by the stop control in which the control parameter at the normal time is set.

  Next, referring to FIG. 15, the battery 1 is fully charged while the vehicle is traveling on a flat road, and in a scene where the amount of braking increases because the regenerative power is limited, the vehicle is Control results in a scene that is in a slip state will be described.

  Fig.15 (a) shows the time chart of the control result by a prior art example, FIG.15 (b) shows the time chart of the control result by this embodiment. FIG. 14 shows a torque command value, a vehicle speed V, a slip ratio, a longitudinal acceleration, a disturbance torque estimated value, and a braking amount in order from the top. Further, a dotted line in the drawing showing a torque command value indicates a stop control stop determination flag flg_stop (0: stop control continued, 1: stop control stop). The dotted line in the figure showing the vehicle speed V shows the vehicle speed Vc.

  Further, on the time axis indicated by the horizontal axis, the road surface state changes as follows. That is, time t0 to t2 is a high μ road such as a normal asphalt road surface, time t2 to t4 is a low μ road such as an icing road, and time t4 to t6 is a high μ road.

  First, the control result according to the conventional example will be described with reference to FIG.

  At time t0, since battery 1 is fully charged, braking is performed by the rise of brake braking amount B regardless of the driver's accelerator pedal operation, and the disturbance torque estimated value estimates a value equivalent to a flat road. doing.

  After time t1, since the vehicle enters a low speed region where regeneration is possible, friction brake braking weakens and regeneration torque starts to increase. Since switching of the regenerative torque and the braking torque by the friction brake 12 is smoothly performed so that the total amount of each braking force does not change, no change in longitudinal acceleration due to the switching occurs. The disturbance torque estimated value is corrected by the brake torque estimated value calculated according to the brake braking amount B, so that it is equivalent to a flat road according to the actual road surface condition.

  From time t2 to time t4, the traveling road surface of the vehicle becomes a low μ road, and the vehicle slips, so the vehicle speed becomes steep and approaches a lock tendency toward zero, and then the slip condition returns to the grip condition, and the vehicle speed increases sharply By doing this, the disturbance torque estimated value moves up and down and becomes vibrational. Therefore, the torque command value (motor torque) calculated based on the disturbance torque estimated value also vibrates. As a result, since the longitudinal acceleration is shaken back and forth, the driver is given an unpleasant vibration.

  Subsequently, control results according to the present embodiment will be described with reference to FIG.

  At time t0, since battery 1 is fully charged, braking is performed by the rise of brake braking amount B regardless of the driver's accelerator pedal operation, and the disturbance torque estimated value estimates a value equivalent to a flat road. doing.

  After time t1, since the vehicle enters a low speed region where regeneration is possible, friction brake braking weakens and regeneration torque starts to increase. Since switching of the regenerative torque and the braking torque by the friction brake 12 is smoothly performed so that the total amount of each braking force does not change, no change in longitudinal acceleration due to the switching occurs. The disturbance torque estimated value is corrected by the brake torque estimated value calculated according to the brake braking amount B, so that it is equivalent to a flat road according to the actual road surface condition.

From time t2 to time t4, the road surface on which the vehicle is traveling becomes a low μ road, and the vehicle speed tends to lock rapidly approaching zero. Therefore, in addition to the friction brake braking amount B being turned on, it is determined that the vehicle is in the slip state, so the stop control stop determination flag flg_stop is set to 1 and the third calculated in the stop control processing. The torque target value Tm3 ^* of the above switches to the fourth torque target value Tm4 ^* calculated with reference to the accelerator opening degree-torque table. As a result, the stop control is stopped, and the control is switched to a control that does not cause the motor torque to converge to the disturbance torque estimated value during the stop. As a result, the vehicle is operated based on the fourth torque target value Tm4 ^* calculated according to the driver's accelerator operation, so that the slip tends to converge, and the vibration of the disturbance torque estimated value generated in the conventional example Can be suppressed and the vibration of longitudinal acceleration can be eliminated.

  From time t4 to time t5, the road surface state returns from the low μ road to the high μ road, and the slip state determination flag flg_slip is set to zero. After that, the motor torque is converged to the disturbance torque estimated value by the stop control based on the speed parameter at the start of the stop control which increases the speed responsiveness set in step S713 of FIG. It will decelerate.

  Then, at t5 to t6 after the elapse of T1 time, the vehicle is stopped by the stop control in which the control parameter at the normal time is set.

  As described above, the control device for an electric vehicle according to one embodiment functions as a traveling drive source and also provides the motor 4 for applying regenerative braking force to the vehicle, and a friction braking unit (for example, friction brake 12) for applying friction braking force to the vehicle. Device for realizing a control method of an electric vehicle including: detecting a rotation speed of the motor 4, estimating a disturbance torque acting on the motor 4, and detecting a friction braking amount by a friction braking unit based on a vehicle state Alternatively, the disturbance torque estimated value is corrected according to the friction braking amount estimated value B. Then, when the electric vehicle comes to a stop, torque control (stop control) at the time of stop is performed to control the motor 4 so that the motor torque converges to the disturbance torque estimated value as the rotational speed of the motor 4 decreases. If the friction braking amount estimated value B is larger than the predetermined value set in advance after the shortcoming, the torque control at the time of stopping is stopped, and the driving force characteristic calculated according to the accelerator opening degree and the rotational speed of the motor Execute torque control based on.

  As a result, even if a deviation occurs between the estimated friction braking amount and the braking braking amount actually applied to the vehicle, stop control is canceled if the friction braking amount is larger than a predetermined value set in advance. It becomes possible to control the braking force according to the driver's intention based on the driving force characteristic calculated from the accelerator opening and the motor rotational speed. As described above, when the friction braking amount is released, the motor torque is not converged to the disturbance torque estimated value when the friction braking amount is larger than the predetermined value set in advance. Can prevent the vehicle from moving forward or backward and hold the vehicle in a stopped state.

  Further, according to the control device of the electric vehicle of one embodiment, the friction braking portion is the friction brake 12 acting on the drive wheels 9a and 9b of the electric vehicle, and the friction braking amount acts on the vehicle by the friction brake 12 It is the magnitude of the friction braking force. Further, the amount of friction braking increases or decreases according to the driver's operation of the brake pedal. As a result, when the driver operates the brake pedal at the time of emergency braking by jumping out of a person or the like, it is possible to stop the stop control and leave the braking of the vehicle to the driver's brake pedal operation.

  Further, according to the control device for an electrically powered vehicle of one embodiment, when stopping control is stopped immediately after stopping, the disturbance torque estimated value is maintained when stopping control is stopped, and stopping control is stopped after stopping After that, when the friction braking amount becomes equal to or less than a predetermined value set in advance, the value held when stopping the stop control is set as the initial value of the disturbance torque estimated value, and the stop control is restarted. As a result, when the frictional braking amount becomes equal to or less than a predetermined value on a road surface with a constant slope, the disturbance torque estimated value is used as the initial value with the correct value without stopping calculation of the disturbance torque estimated value at the resumption of stop control. Control can be resumed.

  Further, according to the control device for an electrically powered vehicle of one embodiment, when the friction braking amount becomes equal to or less than a predetermined value after stopping control is stopped immediately after stopping the vehicle, the friction braking amount is in advance. Until the predetermined time T1 elapses after reaching the set predetermined value or less, the quick response of the control parameter related to the stop control is increased, and the torque control based on the driving force characteristic is stopped to execute the stop control. Thereby, the disturbance torque estimated value can be made to promptly coincide with the gradient disturbance when the stop control is resumed.

  Further, according to the control device for an electric vehicle of one embodiment, it is estimated whether or not the drive wheels 9a and 9b of the electric vehicle are slipping, and the friction braking amount is determined from a predetermined value set in advance immediately after stopping. If it is estimated that the drive wheels 9a and 9b are slipping, the stop control is stopped, and the torque control based on the driving force characteristic calculated according to the accelerator opening degree and the rotational speed of the motor Run. Thus, when the vehicle model (Gp (s), Gr (s)) used in the stop control processing is not established due to the vehicle slipping, the stop control is stopped and the motor torque is disturb torque before the stop. Since control is switched to control that does not cause convergence to the estimated value, it is possible to prevent the vehicle from swaying back and forth due to the influence of stop control.

  Further, according to the control device for an electrically powered vehicle of one embodiment, when stopping control is stopped immediately after stopping, the disturbance torque estimated value at the time of stopping the stop control is held, and stopping control is performed after stopping If it is estimated that the amount of friction braking below a predetermined value is detected or estimated and that the drive wheels 9a and 9b are not slipping, the value held when stopping the stop control is The initial value of the estimated value is set, and the torque control based on the driving force characteristic is stopped, and the stop control is restarted. As a result, when the friction braking amount becomes equal to or less than the predetermined value on the road surface with a constant slope and the vehicle returns from the slip state to the grip state, the disturbance torque estimated value at the restart of the stop control is not calculated again. The stop control can be restarted with the disturbance torque estimated value as the initial value.

  Further, according to the control device of the electric vehicle of the embodiment, after the stop control is stopped immediately after the stop, the friction braking amount becomes equal to or less than the predetermined value set in advance, and the drive wheels 9a and 9b If it is estimated that slippage has not occurred, the responsiveness of the control parameter related to the stop control is increased and the driving force characteristic is increased until the predetermined time T1 elapses after the amount of friction braking falls below the predetermined value set in advance. Stop the torque control based on and execute the stop control. Thereby, the disturbance torque estimated value can be made to promptly coincide with the gradient disturbance when the stop control is resumed. In addition, even if the road surface condition when the vehicle returns to the grip state and the stop control is resumed is an uphill, the backward movement of the vehicle is suppressed and the vehicle can be stopped quickly.

  The present invention is not limited to the one embodiment described above. For example, in the flow relating to the stop control cancellation determination process described with reference to FIG. 7, all the processes in step S701 to step S703 are sequentially performed, but it is not necessary to execute all the processes. Whether the stop control is to be canceled may be determined based on the brake braking amount estimated value B and the slip state of the drive wheels 9a and 9b (steps S701 and S702) without detecting the SW (step S703).

2 ... Motor controller (disturbance torque estimation unit, disturbance torque correction unit, friction braking amount acquisition unit)
4 ... Motor 6 ... Rotation sensor (motor rotation speed detection unit)
9a, 9b ... driving wheel 11 ... brake controller (friction braking amount acquisition unit)
12 ... Friction brake (friction braking part)

Claims (9)

A control method of an electric vehicle, comprising: a motor that functions as a traveling drive source and that applies regenerative braking force to the vehicle; and a friction braking unit that applies friction braking force to the vehicle.
Detecting the rotational speed of the motor;
Estimating the disturbance torque acting on the motor,
Detecting or estimating a friction braking amount by the friction braking unit based on a vehicle state;
Correcting the disturbance torque according to the friction braking amount;
When the electric vehicle comes to a stop, torque control at the time of stopping is executed to control the motor so that the motor torque converges to the estimated value of the disturbance torque as the rotational speed of the motor decreases.
During and after the stop, when the friction braking amount is larger than a predetermined value set in advance, the torque control at the stop is stopped and the drive calculated according to the accelerator opening degree and the rotational speed of the motor Execute torque control based on force characteristics,
A control method of an electric vehicle characterized in that. The friction braking unit is a friction brake that acts on the wheels of the electric vehicle,
The friction braking amount is a magnitude of a friction braking force applied to the vehicle by the friction brake.
A control method of an electric vehicle according to claim 1, characterized in that. The friction braking amount increases or decreases according to the driver's brake pedal operation.
The control method of the electric vehicle according to claim 2 characterized by things. When stopping the torque control at the time of the stop after the stop, the value of the disturbance torque at the time of stopping the torque control at the stop is held.
After the stop of the stop, after the stop of the torque control at the stop, if the friction braking amount becomes equal to or less than a predetermined value set in advance, the value held when stopping the torque control at the stop is used. While setting to the initial value of the disturbance torque, the torque control at the time of stop is restarted
The control method of the electric vehicle according to any one of claims 1 to 3, characterized in that. If the friction braking amount becomes equal to or less than a predetermined value after the stop of the torque control at the time of the stop after the stop of the stop,
Until the predetermined time elapses after the amount of friction braking falls below a predetermined value, speed responsiveness of the control parameter for torque control at the time of stopping is increased, and torque control based on the driving force characteristic is discontinued. And execute torque control at the time of the stop,
The control method of the electric vehicle according to any one of claims 1 to 4, characterized in that. Estimate whether the drive wheels of the electric vehicle are slipping,
If it is estimated that the friction braking amount is larger than a predetermined value set in advance and the drive wheel is slipping after the vehicle is stopped, the torque control at the time of the stop is canceled and the accelerator opening degree is Execute torque control based on the driving force characteristic calculated according to the rotation speed of the motor and the motor,
The control method of the electric vehicle according to any one of claims 1 to 3, characterized in that. When stopping the torque control at the time of the stop after the stop, the value of the disturbance torque at the time of stopping the torque control at the stop is held.
After stopping the torque control at the time of the stop, the friction braking amount less than a predetermined value is detected or estimated, and it is estimated that the drive wheel is not slipping. Setting the value held when stopping the torque control to the initial value of the disturbance torque, and stopping the torque control based on the driving force characteristic and resuming the torque control at the time of the stop
The control method of the electric vehicle according to claim 6, characterized in that. If it is estimated that the friction braking amount is equal to or less than a predetermined value set in advance after the torque control at the time of the stop is stopped and the drive wheel is not slipping, after the stop of the stop.
Until the predetermined time elapses after the amount of friction braking falls below a predetermined value, speed responsiveness of the control parameter for torque control at the time of stopping is increased, and torque control based on the driving force characteristic is discontinued. Restart the torque control at the time of the stop,
The control method of the electric vehicle according to claim 7 characterized by things. A control device for an electric vehicle, comprising: a motor that functions as a traveling drive source and that applies regenerative braking force to the vehicle; and a friction braking unit that applies friction braking force to the vehicle.
A motor rotation speed detection unit that detects the rotation speed of the motor;
A disturbance torque estimation unit that estimates disturbance torque acting on the motor;
A friction braking amount acquisition unit that detects or estimates a friction braking amount by the friction braking unit based on a vehicle state;
A disturbance torque correction unit that corrects the disturbance torque in accordance with the friction braking amount;
When the electric vehicle comes to a stop, torque control at the time of stop is performed to control the motor torque to converge to the estimated value of the disturbance torque as the rotational speed of the motor decreases.
During and after the stop, when the friction braking amount is larger than a predetermined value set in advance, the torque control at the stop is stopped and the drive calculated according to the accelerator opening degree and the rotational speed of the motor Execute torque control based on force characteristics,
A control device of an electric vehicle characterized in that.

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