Control Method and Control Device for Electric Vehicle

Abstract

To provide a method for controlling an electric vehicle which improves an effect for suppressing torsional oscillation of a driving shaft.SOLUTION: A method for controlling an electric vehicle 10 includes the steps of: calculating a first torque command value Tm1* using a torque target value Tm* and a driving shaft torsional angle speed ωd^ output from a vehicle model 21A; calculating a second toque command value Tm2* on the basis of a rotational speed Nm of a motor; adding the first torque command value Tm1* and the second toque command value Tm2*, and obtaining a final torque command value Tmf*; and controlling a motor torque according to the final torque command value Tmf*. The vehicle model 21A includes a dead zone section simulating a gear back rush. The control method performs torque change direction estimation of estimating whether torque of the motor 4 increases or decreases across the dead zone section S on the basis of the torque target value Tm*, and executes correction processing of correcting the dead zone section S on the basis of the second toque command value Tm2* and the torque change direction.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a control method and a control device for an electric vehicle.

Background Art

[0002] Patent Document 1 discloses a control device for an electric vehicle that suppresses torsional vibration of a drive shaft using a vehicle model in which the characteristics of a power transmission mechanism connected to the drive shaft of a motor are modeled. In this control device for an electric vehicle, a vehicle model having a dead zone simulating the backlash characteristic in which motor torque is not transmitted to the drive shaft is used. Thereby, torsional vibration of the drive shaft can be suppressed even when backlash occurs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the control device for an electric vehicle described in Patent Document 1, due to variations in backlash characteristics during production and aging deterioration of gears due to wear or the like, a deviation occurs between the actual backlash characteristics of the vehicle (the section where gear backlash occurs) and the dead zone of the vehicle model, and there is a risk that the suppression effect of torsional vibration of the drive shaft will decrease.

[0005] In view of the above problems, an object of the present invention is to provide a control method and a control device for an electric vehicle with an improved suppression effect of torsional vibration of a drive shaft.

Means for Solving the Problems

[0006] According to one aspect of the present invention, there is provided a control method for an electric vehicle that calculates a torque command value based on a torque target value set based on vehicle information and controls the torque of a motor connected to a drive wheel based on the torque command value. This control method for an electric vehicle includes a step of calculating a first torque command value by a feedforward operation using the torque target value and the torsional angular velocity of the drive shaft output from a vehicle model that models the characteristics of a power transmission mechanism connected to the drive shaft of the motor, a step of detecting the rotational speed of the motor and calculating a second torque command value by a feedback operation based on the detected value, a step of adding the first torque command value and the second torque command value to obtain a final torque command value, and a step of controlling the motor torque according to the final torque command value. The vehicle model includes a section that simulates gear backlash where motor torque is not transmitted to the drive shaft and includes a dead zone estimated based on the torque target value. Then, the control method for the electric vehicle performs an estimation of the torque change direction to estimate whether the torque of the motor increases or decreases across the dead zone based on the torque target value, and executes a correction process for correcting the dead zone based on the second torque command value and the torque change direction.

Effect of the Invention

[0007] According to the present invention, the dead zone of the vehicle model is corrected based on the second torque command value and the torque change direction. Thereby, the deviation between the actual backlash characteristics of the vehicle and the dead zone of the vehicle model can be reduced, and vibrations and noises of the vehicle due to torsional vibrations of the drive shaft can be suppressed even when backlash occurs. That is, the effect of suppressing torsional vibrations of the drive shaft is improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8a

Figure 8b

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like.

[0010] (First Embodiment) FIG. 1 is a block diagram showing the system configuration of an electric vehicle 10 provided with a control device 2 for an electric vehicle according to the first embodiment. The electric vehicle 10 is an automobile equipped with a motor 4 as part or all of the driving source of the vehicle and capable of traveling by the driving force of the motor 4, and includes an electric vehicle and a hybrid vehicle.

[0011] The control device 2 of the electric vehicle is a motor controller. Signals indicating vehicle states such as vehicle speed V, accelerator opening θa, rotor phase α of the motor 4, and three-phase alternating currents iu, iv, iw of the motor 4 are input into the motor controller 2 as digital signals. The motor controller 2 generates PWM signals tu, tv, tw for controlling the motor 4 based on the input signals. Further, drive signals for the inverter 3 are generated according to the generated PWM signals tu, tv, tw.

[0012] The inverter 3 converts the 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 or MOS-FETs) provided for each phase, and causes a desired current to flow through the motor 4.

[0013] The motor (three-phase alternating current 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 drive wheels 9a, 9b via the reduction gear 5 and the drive shaft 8. Further, when the motor 4 rotates while being rotated by the drive wheels 9a, 9b during the running of the vehicle, the motor 4 generates a regenerative driving force to recover the kinetic energy of the vehicle as electric energy. In this case, the inverter 3 converts the alternating current generated during the regenerative operation of the motor 4 into direct current and supplies it to the battery 1.

[0014] The current sensor 7 detects the three-phase alternating currents iu, iv, iw flowing through the motor 4. However, since the sum of the three-phase alternating currents iu, iv, iw is 0, it is also possible to detect any two-phase currents and obtain the remaining one-phase current by calculation.

[0015] The rotation sensor 6 is, for example, a resolver or an encoder, and detects the rotor phase α of the motor 4.

[0016] Figure 2 is a flowchart showing the flow of processing performed by the motor controller 2. The processing according to steps S101 to S105 is always executed at regular intervals while the vehicle system is activated.

[0017] In step S101, a signal (vehicle information) indicating the vehicle state is input to the motor controller 2. Here, the vehicle speed V (km / h), the accelerator opening (%) and the rotor phase α (rad) of the motor 4 are input. Also, the rotational speed Nm (rpm) of the motor 4, the three-phase alternating currents iu, iv, iw flowing through the motor 4, and the DC voltage value Vdc (V) of the battery 1 are input.

[0018] The vehicle speed V (km / h) is obtained by communication from a vehicle speed sensor (not shown) or other controller. Alternatively, the motor controller 2 multiplies the motor angular velocity detection value ωm by the tire dynamic radius r and divides by the gear ratio of the final gear to obtain the vehicle speed V (m / s), and then performs unit conversion to obtain the vehicle speed V (km / h).

[0019] The accelerator opening θa (%) is obtained from an accelerator opening sensor (not shown) or by communication from other controllers such as a vehicle controller (not shown).

[0020] The rotor phase α (rad) of the motor 4 is obtained from the rotation sensor 6. The motor angular velocity detection value ωm, which is the mechanical angular velocity 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. The rotational speed Nm (rpm) of the motor 4 is obtained by multiplying the obtained motor angular velocity detection value ωm by 60 / (2π). The rotor angular velocity ω is obtained by differentiating the rotor phase α. In this embodiment, the motor rotational speed Nm (rpm) is calculated by a motor rotational speed detection unit (not shown) outside the motor controller 2 including the rotation sensor 6, but it may also be configured to be calculated inside the motor controller 2.

[0021] The three-phase alternating currents iu, iv, iw (A) flowing through the motor 4 are obtained from the current sensor 7.

[0022] The DC voltage value Vdc(V) is detected by a voltage sensor (not shown) provided on a DC power supply line between the battery 1 and the inverter 3. The DC voltage value Vdc(V) may be detected from a signal related to the power supply voltage value transmitted from a battery controller (not shown).

[0023] In step S102, the motor controller 2 determines the torque target value Tm as the basic target torque. * Specifically, the motor controller 2 sets the torque target value Tm by referring to the accelerator opening degree-torque table shown in FIG. * However, the accelerator opening-torque table is only an example, and is not limited to the one shown in FIG.

[0024] In step S103, the motor controller 2 calculates the torque target value Tm * and the motor angular velocity detection value ωm are input, and the final torque command value Tm is calculated to suppress the vibration of the driving force transmission system (such as the torsional vibration of the drive shaft 8) without sacrificing the torque response of the drive shaft 8. f * Set the final torque command value Tm f * The method for setting this will be described in detail later.

[0025] In step S104, the motor controller 2 calculates the final torque command value Tm f * , the motor angular velocity detection value ωm, and the DC voltage value Vdc, the d-axis current command value id * , q-axis current command value iq * For example, the final torque command value Tm f *A table is prepared in advance that defines the relationship between the rotation speed Nm of the motor 4, the DC voltage value Vdc, and the d-axis current command value and the q-axis current command value. By referring to this table, the d-axis current command value id * , q-axis current command value iq * Request.

[0026] In step S105, the motor controller 2 performs current control to make the d-axis current id and the q-axis current iq coincide with the d-axis current command value id * and the q-axis current command value iq * respectively. For this purpose, first, based on the three-phase alternating current iu, iv, iw input in step S101 and the rotor phase α of the motor 4, the d-axis current id and the q-axis current iq are obtained. Subsequently, the d-axis voltage command value vd is calculated from the deviation between the d-axis current command value id * and the d-axis current id, and the q-axis voltage command value vq is calculated from the deviation between the q-axis current command value iq * and the q-axis current iq. Note that a non-interference voltage necessary to cancel the interference voltage between the d-q orthogonal coordinate axes may be added to the calculated d-axis voltage command value vd and q-axis voltage command value vq

[0027] Next, the three-phase alternating voltage command values vu, vv, vw are obtained from the d-axis voltage command value vd, the q-axis voltage command value vq, and the rotor phase α of the motor 4. Then, the PWM signals tu(%), tv(%), tw(%) are obtained from the obtained three-phase alternating voltage command values vu, vv, vw and the DC voltage value Vdc. By opening and closing the switching elements of the inverter 3 with the PWM signals tu, tv, tw thus obtained, the motor 4 can be driven with the desired torque indicated by the torque command value (final torque command value Tm f * ).

[0028] FIG. 4 is an example of a control block diagram for performing the process of setting the final torque command value Tm f * . The vibration suppression control calculation unit 20 for setting the final torque command value Tm f * is composed of a vibration suppression control feedforward calculation unit (vibration suppression control FF calculation unit) 21, a vibration suppression control feedback calculation unit (vibration suppression control FB calculation unit) 22, and an adder 23

[0029] The vibration control FF calculation unit (feedforward calculation unit) 21 receives the torque target value Tm * as an input, and the vibration control FF calculation unit 21 calculates and outputs the first torque command value Tm1 * and the estimated motor rotation speed Nm^ for the first torque command value Tm1 * . Details of the calculation of the vibration control FF calculation unit 21 will be described later.

[0030] The vibration control FB calculation unit (feedback calculation unit) 22 receives the estimated motor rotation speed Nm^ for the first torque command value Tm1 * and the motor rotation speed Nm calculated from the detected motor angular velocity ωm, and the vibration control FB calculation unit 22 calculates and outputs the second torque command value Tm2 * . Details of the calculation of the vibration control FB calculation unit 22 will be described later.

[0031] The adder 23 adds the first torque command value Tm1 * and the second torque command value Tm2 * to output the final torque command value Tm f * .

[0032] FIG. 5 is a block diagram of the vibration control FF calculation unit 21 and the vibration control FB calculation unit 22 in the vibration control calculation unit 20 that constitutes the control device 2 of the electric vehicle according to the first embodiment. First, the calculation in the vibration control FF calculation unit 21 will be described. As shown in FIG. 5, the vibration control FF calculation unit 21 includes a vehicle model 21A constituted by a dead zone model that simulates vehicle parameters and gear backlash. Further, a control system delay element 21C and a drive shaft torsional angular velocity FB calculation unit 21D that subtracts a value obtained by multiplying the estimated torsional angular velocity (ωd^, pseudo torsional angular velocity, torsional angular velocity) of the drive shaft 8 by a gain K FB1 (feedback gain) from the torque target value Tm * .

[0033] The drive shaft torsional angular velocity FB command value T FB which is the output of the drive shaft torsional angular velocity FB calculation unit 21D, and the control calculation time e which is the control system delay element 21C-L1s The value considering the motor response delay Ga(s) is input to the vehicle model 21A, and the estimated torsional angular velocity ωd^ is obtained. To the obtained estimated torsional angular velocity ωd^, the sensor signal processing time e -L1s which is the control system delay element 21C is considered, and the value obtained by multiplying by the feedback gain K FB1 is subtracted from the torque target value Tm * and the value obtained by the subtraction is used as the drive shaft torsional angular velocity FB command value T FB which is used as the first torque command value Tm1 * . The dead zone correction unit 21B receives the torque target value Tm * and the second torque command value Tm2 calculated by the vibration control FB calculation unit 22 * and based on these, the dead zone correction unit 21B corrects the dead zone interval estimated in the vehicle model 21A.

[0034] First, the vehicle model 21A will be described. FIG. 6 is a diagram modeling the drive force transmission system (power transmission mechanism) of the electric vehicle 10. Based on FIG. 6, the equations of motion of the electric vehicle 10 are the following equations (1) to (6).

Equation

Equation

Equation

Equation

Equation

Equation

[0035] Here, each parameter is as follows. Jm: Motor inertia Jw: Drive shaft inertia (for one shaft) M: Vehicle mass Kd: Torsional stiffness of the drive shaft Kt: Coefficient related to the friction between the tire and the road surface N: Overall gear ratio r: Tire load radius ωm: Motor angular velocity ωw: Drive wheel angular velocity Tm: Motor torque Td: Drive shaft torque F: Driving force (for two axles) V: Vehicle body speed θ: Torsional angle of the drive shaft

[0036] (1) to (6) equations are Laplace-transformed to obtain the transfer characteristics from the motor torque Tm (torque target value Tm * ) to the motor angular velocity (motor angular velocity estimated value ωm^), and the following equations (7) and (8) are obtained.

Equation

Equation

[0037] However, each parameter is as follows.

Equation

Equation

Equation

Equation

Equation

Equation

Equation

Equation

[0038] Also, the transmission characteristics from the motor torque Tm to the drive shaft torque Td are expressed by the following equation (17).

Number

[0039] However, each parameter is as follows according to the following equation.

Number

Number

[0040] When obtaining the transmission characteristics from the motor angular velocity (estimated motor angular velocity ωm^) to the drive wheel angular velocity ωw from equations (2), (4), (5), and (6), the following equation (20) is obtained.

Number

[0041] From equations (7), (8), and (20), the transmission characteristics from the motor torque Tm to the drive wheel angular velocity ωw are expressed by the following equation (21).

Number

[0042] From equations (17) and (21), the transmission characteristics from the drive shaft torque Td to the drive wheel angular velocity ωw are expressed by the following equation (22).

Number

[0043] When equation (1) is transformed,

Number

Number

[0044] However, Hw in equation (24) is expressed by the following equations (25) to (29).

Number

Number

Number

Number

Number

[0045] Also, when modeling the backlash characteristic from the motor 4 to the driving shaft 8 with a dead zone, the driving shaft torque Td is expressed by the following equation (30).

[0046]

Number

[0047] Next, the dead zone correction unit 21B will be described.

[0048] The dead zone correction unit 21B corrects the difference between the actual backlash characteristic of the gears of the electric vehicle 10 and the dead zone interval of the vehicle model 21A.

[0049] The dead zone correction unit 21B receives the torque target value Tm * and the second torque command value Tm2 calculated by the vibration control FB calculation unit 22 described later * .

[0050] The dead zone correction unit 21B estimates the torque change direction to estimate whether the torque of the motor 4 increases or decreases across the dead zone from the input torque target value Tm * . Then, based on the second torque command value Tm2 * and the estimated torque change direction, the dead zone of the vehicle model 21A is shortened or lengthened by a predetermined value. The details of the dead zone correction method in the dead zone correction unit 21B will be described later

[0051] Next, the control system delay element 21C will be described

[0052] In the control system delay element 21C, the control calculation time delay e -L1s , the motor response delay Ga(s), and the sensor signal processing time delay e -L2s are taken into account. Here, L1 and L2 are the control calculation time and the sensor signal processing time, respectively. The control calculation time corresponds to the time required for the torsional vibration control calculation, that is, the time delay from when the torque target value Tm * is input until the final torque command value Tm f * is calculated. The sensor signal processing time corresponds to the time delay for detecting signals with various sensors such as the rotation sensor 6 and the time delay for processing the detected signal values

[0053] The motor response delay Ga(s) is expressed by the following equation (31). The motor response delay Ga(s) is the time until the actual motor torque Tm is generated with respect to the final torque command value Tm f * . However, τ a is the motor response time constant

Equation

[0054] Next, the drive shaft torsional angular velocity FB calculation unit 21D will be described.

[0055] The drive shaft torsional angular velocity FB command value T FB is represented by the following equation (32) using the estimated value of the drive shaft torsional angular velocity (ωd^ = (ωm / N) - ωw) calculated from the vehicle model 21A.

Equation

[0056] Furthermore, the above equation can be rewritten as the following equation (33) from equations (4) and (6).

Equation

[0057] Also, equation (17) can be transformed as the following equation (34).

Equation

[0058] Furthermore, when examining the poles and zeros of equation (34), since α ≒ c0 / c1, pole-zero cancellation results in the following equation (35).

Equation

[0059] From equations (33) and (35), when the drive shaft torsional angular velocity FB command value T FB is subtracted from the motor torque Tm (torque target value Tm * ), the drive shaft torque Td is represented by the following equation (36).

Equation

[0060] When the formula (36) is transformed, the transmission characteristics of the driving shaft torsional angular velocity in the FB system are represented by the following formula (37).

Number

[0061] The normalized response that idealizes the torque response from the motor 4 to the driving shaft 8 is Tm * Considering that the response from Tm

Number

[0062] The condition for the transmission characteristics of the driving shaft torsional angular velocity in the FB system to match the normalized response is given by the following formula (39).

Number

[0063] From formula (39), the feedback gain K FB1 is determined by the following formula (40).

Number

[0064] As shown in Fig. 5, the vehicle model 21A includes a negative feedback loop 211 consisting of a subtractor 211a, an integrator 211b that generates ωd^, an integrator 211c that generates θ, a dead zone element 211d (I(θ)), a proportional element 211e (Kd), a filter 211f (Hw(s)), and a subtractor 211a.

[0065] On the positive side of the subtractor 211a, the driving shaft torsional angular velocity FB command value T FB which is the output of the driving shaft torsional angular velocity FB calculation unit 21D, and the control operation time e -L1sThe value Tm that takes into account the motor response delay Ga(s) is input through the proportional element 212 (1 / JmN) (Tm / JmN). The output (Hw(s)·Td) of the filter 211f (Hw(s)) is input to the minus side of the subtracter 211a. Also, the value obtained by taking into account the sensor signal processing time delay e is output to the drive shaft torsional angular velocity FB calculation unit 21D from the output of the integral element 211b ((Equation (24))). -L2s The value obtained by taking into account e is output to the drive shaft torsional angular velocity FB calculation unit 21D.

[0066] In the dead zone element 211d (I(θ)), for θ calculated by the integral element 211c, it is converted as follows in Equation (41) according to Equation (30).

Equation

[0067] Also, the vehicle model 21A outputs, to the drive shaft torsional angular velocity FB command value T FB the difference between the output (Td / Jm) that has passed through the proportional element 213 (1 / Jm) of the value Tm that takes into account the control system delay element 21C, the control calculation time e -L1s and the motor response delay Ga(s), and the output (Td / JmN) that has passed through the proportional element 214 (1 / JmN) of the output (Td) of the proportional element 211e (Kd) by means of a subtracter 215. Furthermore, it includes an integral element 216 that outputs the estimated motor angular velocity ωm^ ((Equation (23))) obtained by integrating the output of the subtracter 215. Therefore, the vehicle model 21A performs an estimated value calculation process of the estimated motor angular velocity ωm^ and can estimate the motor speed Nm^ with respect to the first torque command value Tm1 *

[0068] As shown in FIG. 5, the drive shaft torsional angular velocity FB calculation unit 21D multiplies the output (ωd^) of the integral element 211b, which is a value taking into account the sensor signal processing time delay e -L2s by the gain K FB1 using a proportional element 217 (K FB1 ), and calculates the difference between the torque target value Tm * and the output of the proportional element 217 as the first torque command value Tm1 * ​It has a subtractor 218 that outputs as such. Therefore, the drive shaft torsional angular velocity FB calculation unit 21D can, as a result, perform a feed-forward process.

[0069] Next, the vibration control FB calculation unit 22 will be described.

[0070] The vibration control FB calculation unit 22 includes a subtractor 221 and a filter 222. The subtractor 221 outputs the difference between the estimated motor rotation speed Nm^ of the motor 4 with respect to the first torque command value Tm1 calculated by the vehicle model 21A of the vibration control FF calculation unit 21 * and the detected motor rotation speed (motor rotation speed detection value) Nm of the motor 4 obtained from the detected motor angular velocity ωm. The vibration control FB calculation unit 22 passes the difference output from the subtractor 221 through a filter 222 (H(s) / Gp(s)) composed of the inverse characteristic of the transfer characteristic Gp(s) ((8) formula) and a band-pass filter H(s) to calculate a second torque command value Tm2 * This band-pass filter H(s) has a center frequency that coincides with the torsional resonance frequency of the vehicle's drive system.

[0071] In the control device 2 of the electric vehicle configured as described above, since a vehicle model 21A having a dead zone simulating the backlash characteristic of the gear is used, it is possible to suppress the drive shaft torsional vibration even when gear backlash occurs.

[0072] By the way, even when using a vehicle model having a dead zone, due to variations in the gear backlash characteristics during production and the aging deterioration of the gear due to wear, etc., a deviation occurs between the actual backlash characteristic of the vehicle and the dead zone of the vehicle model, and there is a risk that the suppression effect of the drive shaft torsional vibration will decrease.

[0073] In contrast, the control device 2 of the electric vehicle of this embodiment estimates whether the torque of the motor 4 rises or decreases across the dead zone from the torque target value Tm * (torque change direction), and the second torque command value Tm2 *Based on the estimated torque change direction, it is provided with a dead zone correction unit 21B that corrects the dead zone of the vehicle model 21A. Therefore, the deviation between the actual backlash characteristics of the electric vehicle 10 and the dead zone of the vehicle model 21A can be reduced, and vibrations and noises of the electric vehicle 10 caused by torsional vibrations of the drive shaft can be suppressed even when backlash occurs. That is, the suppression effect of the drive shaft torsional vibration is improved.

[0074] Hereinafter, the details of the correction process by the dead zone correction unit 21B will be described.

[0075] FIG. 7 is a diagram showing the operating state of the electric vehicle 10 when the dead zone and the gear backlash characteristics of the electric vehicle 10 (the section where gear backlash occurs) coincide, and is a diagram in a scene where the electric vehicle 10 changes from a decelerated state to acceleration. (a) in FIG. 7 shows the torque target value Tm * and the final torque command value Tm f * (that is, the torque generated in the motor 4), and (b) shows the change in the second torque command value Tm2 * . Further, (c) shows the change in the acceleration of the electric vehicle 10. If the torsional vibration of the drive shaft of the electric vehicle 10 is not suppressed, the fluctuation of the acceleration (the vertical fluctuation of the graph) will increase.

[0076] In FIG. 7, the period from time t1 to t2 is the dead zone S. t1 is the time when the torque target value Tm * changes from negative to positive, and t2 is the time after a predetermined time has elapsed from t1. In the dead zone S, the final torque command value Tm f * becomes 0. Also, in FIG. 7, the final torque command value Tm f * (the torque generated in the motor 4) rises from negative to positive across the dead zone S, and the electric vehicle 10 is transitioning from a decelerated state to an accelerated state.

[0077] As shown in FIG. 7, when the dead zone of the vehicle model 21A coincides with the actual backlash characteristics of the electric vehicle 10, the second torque command value Tm2* takes a substantially constant value of 0, including the dead zone interval S. Also, compared with the case where the dead zone interval S and the gear backlash characteristics of the electric vehicle 10 deviate (Figs. 8a and 8b), the fluctuation of the acceleration of the electric vehicle 10 is small. That is, the torsional vibration of the drive shaft of the electric vehicle 10 is suppressed. The acceleration of the electric vehicle 10 can be detected by a G-sensor or the like.

[0078] Figs. 8a and 8b are diagrams showing the operating state of the electric vehicle 10 when the dead zone interval S and the gear backlash characteristics of the electric vehicle 10 deviate. Fig. 8a is a diagram showing the operating state of the electric vehicle 10 when the dead zone interval S is larger than the actual backlash characteristics of the electric vehicle 10, and Fig. 8b is a diagram showing the operating state of the electric vehicle 10 when the dead zone interval S is smaller than the actual backlash characteristics of the electric vehicle 10. Similar to Fig. 7, Figs. 8a and 8b are also diagrams in the scenario where the electric vehicle 10 transitions from a decelerating state to accelerating. Also, similar to Fig. 7, in Figs. 8a and 8b, (a) shows the change in the torque target value Tm * and the final torque command value Tm f * and (b) shows the change in the second torque command value Tm2 * and (c) shows the change in the acceleration of the electric vehicle 10. In Fig. 8a, the time period from t11 to t12, and in Fig. 8b, the time period from t21 to t22 are the dead zone intervals S.

[0079] As shown in Fig. 8a, when the dead zone interval S of the vehicle model 21A is larger than the actual backlash characteristics of the electric vehicle 10, a large fluctuation appears in the acceleration of the electric vehicle 10 immediately before and after the time t12. That is, it can be seen that the torsional vibration of the drive shaft is not effectively suppressed. This is because in the vehicle model 21A, the gear backlash amount is estimated to be larger than the actual value, so too much play is packed, and the gears collide with each other before passing through the dead zone interval S.

[0080] Here, when the dead zone section S of the vehicle model 21A is larger than the actual backlash characteristic of the electric vehicle 10, in the section where there is actually no gear backlash in the dead zone section S, in the vehicle model 21A, inertia and friction are estimated to be smaller than the actual values. For this reason, the rotational speed of the motor 4 (motor rotational speed detection value) Nm does not increase up to the estimated motor rotational speed Nm^ with respect to the first torque command value Tm1 calculated by the vehicle model 21A. Therefore, the second torque command value Tm2 calculated from the difference between the estimated motor rotational speed Nm^ and the motor rotational speed detection value Nm * becomes a positive value for a certain period of time from the time t12 when passing through the dead zone section S ((b) in FIG. 8a). *

[0081] As described above, when the electric vehicle 10 transitions from a decelerating state to an accelerating state and the dead zone section S of the vehicle model 21A is larger than the actual backlash characteristic of the electric vehicle 10, the second torque command value Tm2 * takes a positive value for a certain period of time from around the time t12 when passing through the dead zone section S. Therefore, in such a case, the dead zone correction unit 21B shortens the dead zone section S by a predetermined value. As a result, the deviation between the dead zone section S and the actual backlash characteristic is reduced.

[0082] On the other hand, as shown in FIG. 8b, even when the dead zone section S of the vehicle model 21A is smaller than the actual backlash characteristic of the electric vehicle 10, after passing through the dead zone section S, a large fluctuation appears in the acceleration of the electric vehicle 10. That is, the torsional vibration of the drive shaft is not effectively suppressed. This is because in the vehicle model 21A, the gear backlash amount is estimated to be smaller than the actual value, so the torque of the motor 4 starts to increase in a state where the backlash backlash is not completed.

[0083] Here, when the dead zone section S of the vehicle model 21A is smaller than the actual backlash characteristic of the electric vehicle 10, since gear backlash actually occurs even after passing through the dead zone section S, in the vehicle model 21A, inertia and friction after passing through the dead zone section S are estimated to be larger than the actual values. Therefore, the rotational speed of the motor 4 (motor rotational speed detection value) Nm rises beyond the estimated motor rotational speed Nm^ with respect to the first torque command value Tm1 * calculated by the vehicle model 21A. Accordingly, as shown in FIG. 8b (b), the second torque command value Tm2 * calculated from the difference between the estimated motor rotational speed Nm^ and the motor rotational speed detection value Nm takes a negative value for a certain period of time after passing through the dead zone section S.

[0084] As described above, when the electric vehicle 10 transitions from a decelerating state to an accelerating state and the dead zone section S of the vehicle model 21A is smaller than the actual backlash characteristic of the electric vehicle 10, after the time t22 when passing through the dead zone section S, the second torque command value Tm2 * takes a negative value for a certain period of time. Accordingly, in such a case, the dead zone correction unit 21B lengthens the dead zone section S by a predetermined value. Thereby, the deviation between the dead zone section S and the actual backlash characteristic is reduced.

[0085] In FIGS. 8a and 8b, the case where the electric vehicle 10 transitions from a decelerating state to an accelerating state has been described. However, even when the torque of the motor 4 transitions from an accelerating state to a decelerating state across the dead zone section S, the dead zone section S can be corrected in the same manner. In this case, when the dead zone section S of the vehicle model 21A is larger than the actual backlash characteristic of the electric vehicle 10, the second torque command value Tm2 * takes a negative value for a certain period of time from the time when passing through the dead zone section S. Conversely, when the dead zone section S of the vehicle model 21A is smaller than the actual backlash characteristic of the electric vehicle 10, after passing through the dead zone section S, the second torque command value Tm2 *takes a positive value. Therefore, when the torque of the motor 4 decreases across the dead zone S, the second torque command value Tm2 after passing through the dead zone S by the dead zone correction unit 21B * is a negative value, the dead zone S is corrected to be shortened by a predetermined value, and the second torque command value Tm2 after passing through the dead zone S * is a positive value, the dead zone S is corrected to be lengthened by a predetermined value. Thereby, the deviation between the dead zone S and the actual backlash characteristic is reduced.

[0086] Also, in either the case of shortening the dead zone S (Fig. 8a) or lengthening the dead zone S (Fig. 8b), the correction amount (predetermined value) can be arbitrarily determined. For example, if the correction amount is small or large so that the corrected dead zone S does not match the actual backlash characteristic, when the torque of the motor 4 crosses the dead zone S again, the second torque command value Tm2 * becomes a positive or negative value, and the dead zone S is corrected again. That is, even if the dead zone S does not match the actual backlash characteristic in one correction, each time the correction is made again, the dead zone S approaches the actual backlash characteristic.

[0087] Fig. 9 is a flowchart for explaining the correction process of the dead zone S. Note that the following processes are all repeatedly executed by the dead zone correction unit 21B (motor controller 2) at predetermined time intervals. Also, the torque target value Tm * and the second torque command value Tm2 * are input to the dead zone correction unit 21B.

[0088] Steps S11 and S12 are torque change direction estimation steps for estimating whether the torque of the motor 4 increases or decreases across the dead zone S.

[0089] In step S11, the dead zone correction unit 21B calculates the torque target value Tm *Based on this, it is determined whether there is gear backlash. Specifically, the torque target value Tm set by the motor controller 2 * has its sign changed from negative to positive, or from positive to negative between the previous value and the current value (i.e., the torque target value Tm * crosses 0), it is determined that there is gear backlash. On the other hand, when the signs of the previous value and the current value of the torque target value Tm * are the same, it is determined that there is no gear backlash.

[0090] In step S11, if it is determined that there is gear backlash, the dead zone correction unit 21B executes the process of step S12. On the other hand, if it is determined that there is no gear backlash, the correction process of the dead zone S ends.

[0091] In step S12, the dead zone correction unit 21B estimates whether the torque of the motor 4 increases or decreases (torque change direction) across the dead zone S (i.e., the torque target value Tm * crosses 0). When the sign of the torque target value Tm * changes from negative to positive between the previous value and the current value, it is estimated that the torque increases across the dead zone S. On the other hand, when the sign of the torque target value Tm * changes from positive to negative between the previous value and the current value, it is estimated that the torque decreases across the dead zone S. The estimated torque change direction is stored as the determination signal s1. * When the sign of the torque target value Tm changes from positive to negative between the previous value and the current value, it is estimated that the torque decreases across the dead zone S. The estimated torque change direction is stored as the determination signal s1.

[0092] Note that the above method for determining the presence or absence of gear backlash and the method for estimating the torque change direction are just examples and are not limited to these.

[0093] Steps S13 to S15 are steps for determining whether the dead zone S has been passed through.

[0094] In step S13, the dead zone correction unit 21B determines whether the driving force transmission system (referred to as the driving force transmission system) between the motor 4 and the drive wheels 9a and 9b of the electric vehicle 10 has passed through the dead zone section S. Whether it has passed through the dead zone section S can be determined by calculations within the motor controller 2. For example, it can be determined from the relationship between the dead zone section S of the vehicle model 21A and the torque target value Tm * and so on, but it is not limited to this. When the driving force transmission system has not passed through the dead zone section S, the driving force transmission system is in the dead zone section S. In this case, the dead zone correction unit 21B executes the process of step S14.

[0095] On the other hand, in step S13, when it is determined that the driving force transmission system has passed through the dead zone section S, since the driving force transmission system is not in the dead zone section, the dead zone correction unit 21B ends the correction process of the dead zone section S.

[0096] In step S14, the dead zone correction unit 21B estimates whether the driving force transmission system is in the dead zone section based on the torque target value Tm * and the vehicle model 21A. Specifically, the dead zone correction unit 21B calculates an estimated value θd^ of the driving shaft torsional angle based on the domain of the driving shaft torsional angle θ shown in Equation (30). Then, when the estimated value θd^ of the driving shaft torsional angle is 0, it is determined that it is in the dead zone section S, and when it is not 0, it is determined that it is not in the dead zone section S. The determination of whether it is in the dead zone section S is stored as a determination signal s2.

[0097] Note that before step S14, the reason for determining whether the driving force transmission system has passed through the dead zone section S in step S13 is that even when the electric vehicle 10 is stopped, the estimated value θd^ of the driving shaft torsional angle becomes 0. That is, if there is no step S13, there is a risk of misjudging that the driving force transmission system is in the dead zone section S in step S14 even when the electric vehicle 10 stops after passing through the dead zone section S. To avoid such a situation, step S13 is provided.

[0098] In step S15, the dead zone correction unit 21B determines whether or not the passage through the dead zone section S has been completed based on the determination signal s2. Specifically, if the previous determination signal of s2 indicates that the driving force transmission system is in the dead zone section and the current determination signal of s2 indicates that the driving force transmission system is not in the dead zone section, it is determined that the passage through the dead zone section S has been completed. On the other hand, if both the previous and current determination signals of s2 indicate that the driving force transmission system is in the dead zone section, it is determined that the passage through the dead zone section S has not been completed.

[0099] In step S15, if it is determined that the passage through the dead zone section S has been completed, the dead zone correction unit 21B executes the process of step S16. On the other hand, if it is determined that the passage through the dead zone section S has not been completed, the dead zone correction unit 21B executes the process starting from step S11 again.

[0100] Steps S16 to S19 are steps for estimating the magnitude relationship between the dead zone section S and the backlash characteristics.

[0101] In step S16, the dead zone correction unit 21B determines whether or not a predetermined time tc has elapsed since the driving shaft transmission system completed passing through the dead zone section S. The elapse of the predetermined time tc is determined, for example, by starting a timer at the time of the determination in step S15 and determining that the predetermined time tc has elapsed since the completion of the passage through the dead zone section S when the value of the timer is equal to or greater than the predetermined time tc. On the other hand, when the value of the timer is less than the predetermined time tc, it is determined that the predetermined time tc has not elapsed since the completion of the passage through the dead zone section S.

[0102] In step S16, if it is determined that the predetermined time tc has not elapsed since the driving force transmission system completed passing through the dead zone section S, the dead zone correction unit 21B executes the process of step S17. On the other hand, if it is determined that the predetermined time tc has elapsed since the completion of the passage through the dead zone section S, the dead zone correction unit 21B executes the process of step S18.

[0103] In step S17, the dead zone correction unit 21B stores the second torque command value Tm2 calculated by the vibration control FB calculation unit 22. * The second torque command value Tm2 * is stored, for example, by storing it in a ring buffer Btfb that can store the second torque command value Tm2 * for a predetermined time tc.

[0104] In step S17, when the second torque command value Tm2 * is stored, the dead zone correction unit 21B executes the process of step S16 again. As a result, after the drive power transmission system passes through the dead zone section S, the second torque command value Tm2 * during the period until a predetermined time tc elapses is stored in the ring buffer Btfb. Note that the predetermined time tc is set to a value larger than the time from the passing time of the dead zone section S until the time when the second torque command value Tm2 * fluctuates positively or negatively when the dead zone section S and the actual backlash characteristics do not match.

[0105] When a predetermined time tc elapses after the drive power transmission system completes passing through the dead zone section S, the dead zone correction unit 21B calculates, in step S18, the average value Tm2ave * of the second torque command value Tm2 * stored (stored in the ring buffer Btfb) during the period until a predetermined time tc elapses after passing through the dead zone section S.

[0106] In step S19, the dead zone correction unit 21B estimates the magnitude relationship between the dead zone section S and the actual gear backlash characteristics based on the determination signal s1 (torque change direction) stored in step S12 and the average value Tm2ave * of the second torque command value Tm2 * . Specifically, the determination is made as follows. The average value Tm2ave * of the second torque command value Tm2 *When it is 0, it is determined that the dead zone interval S coincides with the actual gear backlash characteristic. In the determination signal s1, the torque change direction crosses the dead zone interval S and the torque of the motor 4 is increasing, and the second torque command value Tm2 * The average value Tm2ave of * is a positive value, it is determined that the dead zone interval S is larger than the actual gear backlash characteristic. In the determination signal s1, the torque change direction crosses the dead zone interval S and the torque of the motor 4 is increasing, and the second torque command value Tm2 * The average value Tm2ave of * is a negative value, it is determined that the dead zone interval S is smaller than the actual gear backlash characteristic. On the contrary, in the determination signal s1, the torque change direction crosses the dead zone interval S and the torque of the motor 4 is decreasing, and the second torque command value Tm2 * The average value Tm2ave of * is a positive value, it is determined that the dead zone interval S is smaller than the actual gear backlash characteristic. Also, in the determination signal s1, the torque change direction crosses the dead zone interval S and the torque of the motor 4 is decreasing, and the second torque command value Tm2 * The average value Tm2ave of * is a negative value, it is determined that the dead zone interval S is larger than the actual gear backlash characteristic.

[0107] Step S20 is a dead zone interval correction step for correcting the dead zone interval S.

[0108] In step S20, the dead zone correction unit 21B corrects the dead zone interval S based on the magnitude relationship between the dead zone interval S determined in step S19 and the actual gear backlash characteristic. That is, in step S19, when it is determined that the dead zone interval S is larger than the actual gear backlash characteristic, the dead zone interval S is corrected to be shortened by a predetermined value. On the other hand, in step S19, when it is determined that the dead zone interval S is smaller than the actual gear backlash characteristic, the dead zone interval S is corrected to be lengthened by a predetermined value. Note that when the dead zone interval S coincides with the actual gear backlash characteristic, the dead zone correction unit 21B does not correct the dead zone interval S.

[0109] When the process of step S20 is executed, the dead zone correction unit 21B finishes the correction process of the dead zone section S.

[0110] In this embodiment, the dead zone section S is corrected based on the torque change direction and the second torque command value Tm2 for a predetermined time tc. * However, the dead zone section S may be corrected after the processes up to step S19 are executed a predetermined number of times. In this case, in step S19, the data on the magnitude relationship between the estimated dead zone section S and the actual gear backlash characteristic is stored in a ring buffer B different from the ring buffer Btfb. Then, after the processes up to step S19 are executed a predetermined number of times, in the data stored in the ring buffer B, if the dead zone section S is all larger than the actual gear backlash characteristic, the dead zone section S is corrected to be shorter, and if the dead zone section S is all smaller than the actual gear backlash characteristic, the dead zone section S is corrected to be longer. In this way, by judging the magnitude relationship between the dead zone section S and the actual gear backlash characteristic a plurality of times before correction, the correction direction (whether to make the dead zone section S smaller or larger) can be judged more accurately.

[0111] Also, in this embodiment, the sign (positive or negative) of the second torque command value Tm2 * is judged by the average value Tm2ave * of the second torque command value Tm2 for a predetermined time tc, but it is not necessarily limited to this. For example, a predetermined reference value may be set, and the sign of the second torque command value Tm2 may be judged based on whether it is larger than the reference value or smaller than the reference value. * * * *

[0112] According to the control method and control device 2 of the electric vehicle 10 of the first embodiment described above, the following effects can be obtained.

[0113] The control method of the electric vehicle 10 is the torque target value Tm *And, using the estimated drive shaft torsional angular velocity (torsional angular velocity) ωd^ output from the vehicle model 21A, the first torque command value Tm1 * A step of calculating, and a second torque command value Tm2 based on the rotational speed Nm of the motor 4 * A step of calculating, and the first torque command value Tm1 * And the second torque command value Tm2 * Are added together to obtain the final torque command value Tm f * A step of obtaining, and a step of controlling the motor torque according to the final torque command value Tm f * The vehicle model 21A includes a dead zone interval that simulates gear backlash and is estimated based on the torque target value Tm * And an estimation of the torque change direction for estimating whether the torque of the motor 4 increases or decreases across the dead zone interval S based on the torque target value Tm * * * Based on the second torque command value Tm2 and the torque change direction, a correction process for correcting the dead zone interval S is executed. In this way, the dead zone interval S of the vehicle model 21A is corrected based on the second torque command value Tm2 * And the torque change direction. Thereby, the deviation between the actual backlash characteristics of the vehicle and the dead zone interval S of the vehicle model 21A can be reduced, and vibrations and noises of the vehicle due to drive shaft torsional vibrations can be suppressed even when backlash occurs. That is, the suppression effect of drive shaft torsional vibrations is improved.

[0114] In the control method of the electric vehicle 10, when the torque of the motor 4 is increasing across the dead zone interval S (that is, in a scene where the electric vehicle 10 transitions from deceleration to acceleration), and the second torque command value Tm2 after passing through the dead zone interval S * Is a positive value, the dead zone interval S is corrected to be shortened by a predetermined value. Also, when the torque of the motor 4 is increasing across the dead zone interval S, and the second torque command value Tm2 after passing through the dead zone interval S *When it is a negative value, the dead zone S is corrected so as to be lengthened by a predetermined value. Thereby, in a scene where the electric vehicle 10 changes from deceleration to acceleration, the dead zone S can be corrected simply and accurately.

[0115] In the control method of the electric vehicle 10, the torque of the motor 4 decreases across the dead zone S (that is, in a scene where the electric vehicle 10 changes from acceleration to deceleration), and the second torque command value Tm2 after passing through the dead zone S * When it is a positive value, the dead zone S is corrected so as to be lengthened by a predetermined value. Further, the torque of the motor 4 decreases across the dead zone S, and the second torque command value Tm2 after passing through the dead zone S * When it is a negative value, the dead zone S is corrected so as to be shortened by a predetermined value. Thereby, in a scene where the electric vehicle 10 changes from acceleration to deceleration, the dead zone S can be corrected simply and accurately.

[0116] The control device 2 of the electric vehicle includes a torque target value Tm * and a drive shaft torsional angular velocity estimated value (torsional angular velocity) ωd^ output from the vehicle model 21A to calculate a first torque command value Tm1 * a vibration control feedforward calculation unit (feedforward calculation unit) 21, and a vibration control feedback calculation unit (feedback calculation unit) 22 that calculates a second torque command value Tm2 * based on the rotational speed Nm of the motor 4. The control device 2 of the electric vehicle includes a dead zone S in which the vehicle model 21A simulates gear backlash. Further, the control device 2 of the electric vehicle estimates whether the torque of the motor 4 increases or decreases across the dead zone S based on the torque target value Tm * and includes a dead zone correction unit 21B that corrects the dead zone S based on the second torque command value Tm2 * and the torque change direction. Thus, the second torque command value Tm2 *Since it is provided with a dead zone correction unit 21B that corrects the dead zone section S of the vehicle model 21A based on the torque change direction, the deviation between the actual backlash characteristics of the electric vehicle 10 and the dead zone section S of the vehicle model 21A can be reduced. Therefore, even when backlash occurs, vibration and noise of the vehicle due to torsional vibration of the drive shaft can be suppressed. That is, the suppression effect of the torsional vibration of the drive shaft is improved.

[0117] In addition, in this embodiment, the correction process of the dead zone section S is executed by the dead zone correction unit 21B having a configuration different from that of the vehicle model 21A. However, the dead zone correction unit 21B may be incorporated inside the vehicle model 21A, and the correction process of the dead zone section S may be executed within the vehicle model 21A.

[0118] (Second Embodiment) With reference to FIG. 10, a control method of the electric vehicle 10 and a control device 2 of the electric vehicle according to the second embodiment will be described. Note that the same reference numerals are given to the same elements as those in the first embodiment, and the description thereof will be omitted.

[0119] FIG. 10 is a flowchart for explaining the correction process by the control method of the electric vehicle 10 and the control device 2 of the electric vehicle according to the second embodiment. In the second embodiment, it is different from the first embodiment in that in the torque change direction estimation step, the correction process is continued (executed) only when the torque change direction is either increasing or decreasing. Note that, similar to the first embodiment, the following processes are all repeatedly executed by the dead zone correction unit 21B (motor controller 2) at predetermined time intervals. Also, the torque target value Tm * and the second torque command value Tm2 * are input to the dead zone correction unit 21B.

[0120] In step S11, the dead zone correction unit 21B determines the presence or absence of gear backlash in the same manner as in the first embodiment. If gear backlash occurs, the dead zone correction unit 21B executes the process of step S22. If gear backlash does not occur, the dead zone correction unit 21B ends the correction process.

[0121] In step S22, the dead zone correction unit 21B estimates the torque change direction based on the torque target value Tm * and determines whether the torque change direction is a predetermined one direction (for example, increasing). When the torque change direction is the predetermined direction (increasing), the correction process is continued. When the torque change direction is not the predetermined direction (decreasing), the correction process is canceled. The estimation of the torque change direction is the same as in the first embodiment, and is estimated based on how the sign of the torque target value Tm * changes between the previous value and the current value (from negative to positive, or from positive to negative). The dead zone correction unit 21B determines whether the torque change direction is a predetermined direction (increasing) based on the estimation of the torque change direction, and continues the correction process only when it is the predetermined direction (increasing). For example, the correction process is continued only when the torque of the motor 4 increases across the dead zone S, and the processes after step S13 are executed. On the other hand, when the torque of the motor 4 decreases across the dead zone S, the correction process is canceled and the processes after step S13 are not executed.

[0122] Thus, in step S22, when the torque change direction is a predetermined one direction (increasing), the dead zone correction unit 21B executes the processes after step S13, and when the torque change direction is not the predetermined one direction (increasing), the correction process is canceled.

[0123] Steps S13 to S18 are the same as in the first embodiment, so the description is omitted.

[0124] When the process of step S18 (calculation of the average value Tm2ave * of the second torque command value Tm2 * ) is executed, the dead zone correction unit 21B executes the process of step S29.

[0125] In step S29, the dead zone correction unit 21B uses the average value Tm2ave * of the second torque command value Tm2 *Based on this, the magnitude relationship between the dead zone interval S and the actual gear backlash characteristic is estimated. The second torque command value Tm2 * The average value Tm2ave * If it is 0, it is determined that the dead zone interval S coincides with the actual gear backlash characteristic. When the predetermined (torque change) direction in step S22 is upward, the second torque command value Tm2 * The average value Tm2ave * If it is a positive value, it is determined that the dead zone interval S is larger than the actual gear backlash characteristic, and if it is a negative value, it is determined that the dead zone interval S is smaller than the actual gear backlash characteristic.

[0126] Since the process of step S20 (dead zone interval correction step) is the same as that of the first embodiment, the description is omitted.

[0127] When the process of step S20 is executed, the dead zone correction unit 21B ends the correction process of the dead zone interval S.

[0128] In this embodiment, an example in which the predetermined (torque change) direction is set to upward has been described, but the predetermined direction may be set to downward. In this case, in step S29, the dead zone correction unit 21B uses the second torque command value Tm2 * The average value Tm2ave * If it is a positive value, it is determined that the dead zone interval S is smaller than the actual gear backlash characteristic, and if it is a negative value, it is determined that the dead zone interval S is larger than the actual gear backlash characteristic.

[0129] Also, similar to the first embodiment, in this embodiment, the process up to step S29 may be executed a predetermined number of times and then the dead zone interval S may be corrected.

[0130] As described above, in this embodiment, the correction process is executed only when the torque change direction is either increasing or decreasing. By thus limiting the torque change direction to one direction and executing the correction process, it is possible to more easily estimate the magnitude relationship between the dead zone S and the backlash characteristics. That is, it is possible to more easily reduce the deviation between the actual backlash characteristics of the electric vehicle 10 and the dead zone S of the vehicle model 21A, and it is possible to more easily improve the suppression effect of the drive shaft torsional vibration.

[0131] Note that, in any of the embodiments, the correction of the dead zone S is performed by making the dead zone S longer or shorter by a predetermined value, but it is not necessarily limited to this. For example, the relationship between the amplitude of the second torque command value Tm2 * and the degree of deviation between the dead zone S and the actual backlash characteristics is obtained in advance by experiments or the like, and the correction amount of the dead zone S may be determined according to the amplitude of the second torque command value Tm2 * .

[0132] The embodiments of the present invention have been described above. However, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0133] Each of the above-described embodiments has been described as an independent embodiment, but they may be combined as appropriate.

Explanation of Reference Numerals

[0134] 2, motor controller (control device of electric vehicle), 10, electric vehicle, 20, vibration suppression control calculation unit, 21, vibration suppression control feed-forward calculation unit, 21A, vehicle model, 21B, dead zone correction unit, 22, vibration suppression control feedback calculation unit

Claims

1. A control method for an electric vehicle that calculates a torque command value based on a torque target value set based on vehicle information and controls the torque of a motor connected to a drive wheel based on the torque command value, a step of calculating a first torque command value by a feedforward operation using the torque target value and the torsional angular velocity of the drive shaft output from a vehicle model that models the characteristics of a power transmission mechanism connected to the drive shaft of the motor; a step of detecting the rotational speed of the motor and calculating a second torque command value by a feedback operation based on the detected value; a step of adding the first torque command value and the second torque command value to obtain a final torque command value; a step of controlling the motor torque according to the final torque command value, including the vehicle model includes a section that simulates gear backlash in which motor torque is not transmitted to the drive shaft, and includes a dead zone estimated based on the torque target value, the control method of the electric vehicle is estimating a torque change direction for estimating whether the torque of the motor increases or decreases across the dead zone based on the torque target value, and performing a correction process for correcting the dead zone based on the second torque command value and the torque change direction. A control method for an electric vehicle.

2. The control method of an electric vehicle according to claim 1, wherein the correction process is executed only when the torque change direction is either an increase or a decrease. A control method for an electric vehicle.

3. The control method of an electric vehicle according to claim 1 or 2, wherein the correction process is when the torque of the motor is increasing in the estimation of the torque change direction and the second torque command value after passing through the dead zone is a positive value, correcting the dead zone to be shortened by a predetermined value, and when the second torque command value after passing through the dead zone is a negative value, correcting the dead zone to be lengthened by a predetermined value. A control method for an electric vehicle.

4. The control method of an electric vehicle according to any one of claims 1 to 3, wherein the correction process is In the estimation of the torque change direction, when the torque of the motor is decreasing and the second torque command value after passing through the dead zone is a positive value, correct to increase the dead zone by a predetermined value, and when the second torque command value after passing through the dead zone is a negative value, correct to decrease the dead zone by a predetermined value. A control method for an electric vehicle.

5. A control device for an electric vehicle that calculates a torque command value based on a torque target value set based on vehicle information and controls the torque of a motor connected to a drive wheel based on the torque command value, A feed-forward calculation unit that calculates a first torque command value by a feed-forward calculation using the torque target value and the drive shaft torsional angular velocity output from a vehicle model that models the characteristics of a power transmission mechanism connected to the drive shaft of the motor, A feedback calculation unit that detects the rotational speed of the motor and calculates a second torque command value by a feedback calculation based on the detected value, The control device for the electric vehicle, controls the motor torque according to the final torque command value obtained by adding the first torque command value and the second torque command value, The vehicle model includes a section that simulates gear backlash in which motor torque is not transmitted to the drive shaft and includes a dead zone estimated based on the torque target value, The control device for the electric vehicle further includes a dead zone correction unit that estimates whether the torque of the motor increases or decreases across the dead zone based on the torque target value, and corrects the dead zone based on the second torque command value and the torque change direction. A control device for an electric vehicle.

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