JP6880675B2 - Electric vehicle control method and electric vehicle control device - Google Patents

Description

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

Conventionally, in a vehicle acceleration / deceleration control system, when the accelerator operation amount is less than a predetermined value, the deceleration is controlled according to the accelerator operation amount, and when the accelerator operation amount is equal to or more than a predetermined value, the acceleration is adjusted according to the accelerator operation amount. A control technique is known (see Patent Document 1). According to this acceleration / deceleration control system, the target acceleration / deceleration can be set according to the accelerator operation amount. Therefore, if the target acceleration / deceleration is set to 0, the accelerator operation can be performed even on a slope road. It is possible to maintain a constant vehicle speed without the need to adjust the amount.

Japanese Unexamined Patent Publication No. 2000-205015

Here, in order to maintain a constant vehicle speed on a slope road without adjusting the accelerator operation amount, the drive torque is corrected according to the road surface gradient to adjust the acceleration / deceleration that changes according to the change in the road surface gradient. It is necessary to control and control the target acceleration / deceleration of the vehicle.

Therefore, in a vehicle equipped with a motor as a traveling drive source, the road surface gradient is estimated based on the rotation speed of the motor and the drive torque output by the motor, and the motor torque is corrected based on the estimated road surface gradient. It controls the acceleration / deceleration of the vehicle.

However, for example, when the drive wheels of the vehicle are separated from the road surface by jacking up, the relationship between the rotation speed of the motor and the drive torque is different from that during normal driving, so that the road surface gradient may be erroneously estimated. As a result, if the motor torque is controlled based on the erroneously estimated road surface gradient, there arises a problem that vibration is generated in the vehicle body.

An object of the present invention is to provide a technique for suppressing vibration in the vehicle body even if the motor torque is controlled in a situation where the road surface gradient is erroneously estimated.

The method for controlling an electric vehicle according to the present invention is a method for controlling an electric vehicle including a motor that functions as a traveling drive source and gives a regenerative braking force to the vehicle, and outputs a control drive torque according to an accelerator operation amount to the motor. The target torque value to be applied is calculated, and the disturbance torque acting on the motor is estimated as the resistance corresponding to the road surface gradient estimated based on the wheel speed and the torque target value. Then, a correction for canceling the disturbance torque component is executed from the torque target value, the motor is controlled based on the corrected torque target value, and the correction is stopped when the fluctuation frequency of the disturbance torque becomes equal to or higher than a predetermined frequency.

According to the present invention, when the disturbance torque estimated value that substantially matches the road surface gradient is determined to be an abnormal value, the correction of the motor torque based on the disturbance torque estimated value is stopped, so that the disturbance torque estimated value is incorrect. It is possible to suppress the vibration of the vehicle body caused by the estimation.

FIG. 1 is a block diagram showing a main configuration of an electric vehicle including a control device for an electric vehicle according to an embodiment. FIG. 2 is a flow of processing of motor current control performed by the motor controller included in the control device of the electric vehicle according to the first embodiment. FIG. 3 is a diagram showing an example of an accelerator opening degree-torque table. FIG. 4 is a diagram for explaining a method of calculating the first torque target value in the first embodiment. FIG. 5 is a diagram for explaining a method of calculating the disturbance torque estimated value. FIG. 6 is a diagram modeling a driving force transmission system of a vehicle. FIG. 7 is a block diagram for realizing the stop control process. FIG. 8 is a diagram for explaining a method of calculating the motor rotation speed F / B torque Tω based on the motor rotation speed ωm. FIG. 9 is a flowchart illustrating the correction possibility determination process in the first embodiment. FIG. 10 is a block diagram for explaining an example of a control block that realizes the correction possibility determination process. FIG. 11 is a block diagram for explaining an example of a control block that realizes the correction possibility determination process. FIG. 12 is a diagram showing an example of a control result by the control device of the electric vehicle of the first embodiment. FIG. 13 is a diagram for explaining a method of calculating the first torque target value in the second embodiment. FIG. 14 is a flowchart illustrating a correction possibility determination process in the second embodiment. FIG. 15 is a diagram showing an example of a control result by the control device of the electric vehicle of the second embodiment. FIG. 16 is a diagram for explaining a method of calculating the first torque target value in the third embodiment. FIG. 17 is a flowchart illustrating a correction possibility determination process according to the third embodiment. FIG. 18 is a diagram showing an example of a control result by the control device of the electric vehicle according to the third embodiment. FIG. 19 is a block diagram for explaining an example of a control block that realizes the correction possibility determination process. FIG. 20 is a block diagram for explaining an example of a control block that realizes a correction possibility determination process.

Hereinafter, an example in which the control device for an electric vehicle according to the present invention is applied to an electric vehicle whose drive source is an electric motor (hereinafter, referred to as an electric motor or simply a motor) will be described.

[First Embodiment]
FIG. 1 is a block diagram showing a main configuration of an electric vehicle provided with a control device for an electric vehicle according to the first embodiment. The control device for an electric vehicle of the present invention is applicable to an electric vehicle that includes an electric motor as a part or all of a drive source of the vehicle and can travel by the driving force of the electric motor. Electric vehicles include not only electric vehicles but also hybrid vehicles and fuel cell vehicles. In particular, the control device for an electric vehicle according to the present embodiment can be applied to a vehicle that can control acceleration / deceleration and stop of the vehicle only by operating the accelerator pedal. In this vehicle, the driver depresses the accelerator pedal when accelerating, and reduces the depressing amount of the accelerator pedal when decelerating or stopping, or sets the depressing amount of the accelerator pedal to zero. On an uphill road, the vehicle may approach a stopped state while depressing the accelerator pedal in order to prevent the vehicle from moving backward.

In the motor controller 2, signals indicating the vehicle state such as vehicle speed V, accelerator opening degree θ, rotor phase α of the motor (three-phase AC motor) 4, and three-phase AC currents iu, iv, and iw of the motor 4 are used as digital signals. Entered. The motor controller 2 generates a PWM signal for controlling the motor 4 based on the input signal. Further, the motor controller 2 controls the opening and closing of the switching element of the inverter 3 according to the generated PWM signal. The motor controller 2 further generates a friction braking amount command value according to the accelerator operation amount by the driver or the operation amount of the brake pedal 10.

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 and MOS-FETs) provided for each phase. Then, a desired current is passed through the motor 4.

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

The current sensor 7 detects the three-phase alternating currents Iu, Iv, and Iw flowing through the motor 4. However, since the sum of the three-phase alternating currents Iu, Iv, and Iw is 0, the current of any two phases may be detected and the current of the remaining one phase may be obtained by calculation.

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

The brake controller 11 outputs to the friction brake 13 a brake actuator command value that generates a brake hydraulic pressure according to the friction braking amount command value generated by the motor controller 2.

The hydraulic pressure sensor 12 functions as a brake braking amount detecting means, detects the brake hydraulic pressure of the friction brake 13, and outputs the detected brake hydraulic pressure (friction braking amount) to the brake controller 11 and the motor controller 2.

The friction brake 13 functions as a friction braking unit. Specifically, the friction brake 13 is provided on each of the left and right drive wheels 9a and 9b, and presses the brake pad against the brake rotor according to the brake fluid pressure to generate a braking force in the vehicle.

The front-rear G sensor 15 mainly detects the front-rear acceleration and outputs the detected value to the motor controller 2. As a result, the motor controller 2 can detect the tilted state of the vehicle in the front-rear direction based on the front-rear G sensor detection value, and can calculate a disturbance torque component that substantially matches the gradient resistance acting on the motor 4.

FIG. 2 is a flowchart showing a processing flow of motor current control programmed to be executed by the motor controller 2.

In step S201, a signal indicating the vehicle state is input to the motor controller 2. Here, the vehicle speed V (m / s), the accelerator opening degree θ (%), the rotor phase α (rad) of the motor 4, the rotation speed Nm (rpm) of the motor 4, and the three-phase direct current iu flowing through the motor 4. The iv, iv, the DC voltage value V _dc (V) between the battery 1 and the inverter 3, the brake operation amount, and the brake hydraulic pressure are input.

The vehicle speed V (km / h) can be obtained from the wheel speed ωw of the wheels (driving wheels 9a, 9b) that transmit the driving force when the vehicle is driven. The vehicle speed V is acquired by communication from the wheel speed sensors 11a and 11b and other controllers (not shown). Alternatively, the vehicle speed V (km / h) is 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 to obtain the vehicle speed v (m / s) and multiply by 3600/1000. It is obtained by converting the unit by doing so.

The accelerator opening degree θ (%) is acquired from an accelerator opening degree sensor (not shown) or by communication from another controller such as a vehicle controller (not shown) as an index indicating the amount of accelerator operation by the driver.

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

The three-phase alternating currents iu, iv, and iwa (A) flowing through the motor 4 are acquired from the current sensor 7.

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

The brake braking amount is acquired from the brake hydraulic pressure sensor value detected by the hydraulic pressure sensor 12. Alternatively, a value (brake operation amount) detected by a stroke sensor (not shown) or the like that detects the amount of depression of the brake pedal by the driver's pedal operation may be used as the brake braking amount.

In the torque target value calculation process in step S202, the motor controller 2 sets ^{the first torque target value Tm1 *.} Specifically, first, the accelerator opening-torque table shown in FIG. 3 showing one aspect of the driving force characteristics calculated according to the accelerator opening θ and the motor rotation speed ωm input in step S201 is displayed. By referring to it, the basic torque target value Tm0 ^* (torque target value) as the driver required torque is set. Subsequently, the disturbance torque estimated value Td that substantially matches the gradient resistance is obtained. Then, by adding the basic torque target value Tm0 ^* and the disturbance torque estimated value Td, the first torque target value Tm1 ^* in which the gradient resistance component is canceled is set.

As described above, the control device for the electric vehicle according to the present embodiment can be applied to a vehicle that can control acceleration / deceleration and stop of the vehicle only by operating the accelerator pedal, and at least by fully closing the accelerator pedal. It is possible to stop the vehicle. Therefore, in the accelerator opening-torque table shown in FIG. 3, when the accelerator opening is 0 (fully closed) or 1/8, a negative motor torque is set so that the regenerative braking force acts. However, the accelerator opening-torque table shown in FIG. 3 is an example and is not limited thereto.

In step S203, the controller 2 performs the stop control process. Specifically, the controller 2 determines whether or not the vehicle is about to stop, and if it is not about to stop, the first torque target value Tm1 ^* calculated in step S202 is set to the motor torque command value Tm ^*, and the vehicle is about to stop. In the case of, the second torque target value Tm2 ^* is set to the motor torque command value Tm ^*. This second torque target value Tm2 ^* converges to the disturbance torque estimated value Td or the disturbance correction torque described later as the motor rotation speed decreases, and is positive torque on an uphill road, negative torque on a downhill road, and flat. It is almost zero on the road. As a result, the stopped state can be maintained regardless of the slope of the road surface.

In the following step S204, the controller 2 performs a current command value calculation process. Specifically, in addition to the torque target value Tm ^* (motor torque command value Tm ^{* ) calculated in step S203, the d-axis current target value id *} and the q-axis current are based on the motor rotation speed ωm and the DC voltage value Vdc. Find the target value iq ^* . For example, by preparing in advance a table that defines the relationship between the torque command value, the motor rotation speed, and the DC voltage value, and the d-axis current target value and the q-axis current target value, by referring to this table, Obtain the d-axis current target value id ^* and the q-axis current target value iq ^*.

In step S205, 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 S204, respectively.} Therefore, first, the d-axis current id and the q-axis current iq are obtained based on the three-phase AC currents iu, iv, and iwa 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 deviations between the d-axis and q-axis current command values id ^* and iq ^{* and the d-axis and q-axis current id and iq.} The non-interference voltage required for canceling the interference voltage between the dq orthogonal coordinate axes may be added to the calculated d-axis and q-axis voltage command values vd and vq.

Then, the three-phase AC voltage command values vu, vv, and vw are obtained from the d-axis and q-axis voltage command values vd and vq and the rotor phase α of the electric motor 4. From the obtained three-phase AC voltage command values vu, vv, vw and the DC voltage value Vdc, the PWM signals tu (%), tv (%), and tw (%) are obtained. By opening and closing the switching element of the inverter 3 by the PWM signals tu, tv, and tw obtained in this way, the electric motor 4 can be driven with a desired torque instructed by the ^{motor torque command value Tm *.}

The details of the process performed in step S202 of FIG. 2, that is, the ^{method of setting the first torque target value Tm1 *} will be described with reference to FIG.

^{The basic torque target value setter 401 sets the basic torque target value Tm0 *} by referring to the accelerator opening degree-torque table shown in FIG. 3 based on the accelerator opening degree and the motor rotation speed ωm.

The disturbance torque estimator 402 obtains the disturbance torque estimated value Td based on the motor torque command value Tm ^* , the motor rotation speed ωm, and the brake braking amount B.

FIG. 5 is a block diagram showing a detailed configuration of the disturbance torque estimator 402. The disturbance torque estimator 402 includes a control block 501, a control block 502, a subtractor 503, and a control block 504.

The control block 501 has a function as a filter having a transmission characteristic of H (s) / Gp (s), and a first motor torque estimated value is performed by inputting a motor rotation speed ωm and performing a filtering process. Is calculated. Gp (s) is a transmission characteristic from the motor torque Tm to the motor rotation speed ωm, and the details will be described later. H (s) is a low-pass filter having a transfer characteristic in which the difference between the denominator order and the numerator order is equal to or greater than the difference between the denominator order and the numerator order of the model Gr (s). Although it was explained that the first motor torque estimated value is calculated from the motor rotation speed ωm on the control block illustrated in FIG. 5 and in the above description, it is used as a speed parameter proportional to the motor rotation speed ωm. The first motor torque estimated value may be calculated from the wheel speed ωw.

The control block 502 functions as a low-pass filter having a transmission characteristic of H (s), and calculates a second motor torque estimated value by inputting ^{a motor torque command value Tm * and performing filtering processing.} To do.

The subtractor 503 calculates the disturbance torque estimated value Td by subtracting the first motor torque estimated value from the second motor torque estimated value. This disturbance torque estimated value Td is a value that generally coincides with the gradient resistance, and is a positive torque on an uphill road, a negative torque on a downhill road, and approximately zero on a flat road.

In the present embodiment, the disturbance torque estimated value Td is calculated by filtering the deviation between the second motor torque estimated value and the first motor torque estimated value by the control block 504. The control block 504 functions as a filter having a transmission characteristic of Hz (s), and performs filtering processing by inputting a deviation between the second motor torque estimated value and the first motor torque estimated value. To calculate the disturbance torque estimated value Td. The details of Hz (s) will be described later.

The explanation will be continued by returning to FIG. The disturbance torque estimate value Td calculated by the disturbance torque estimator 402 is normally input to the adder 404 and added to the basic torque target value Tm0 ^* . As a result, the gradient correction is performed on the basic torque target value Tm0 ^* based on the disturbance torque estimated value Td, and the first torque target value Tm1 ^{* in} which the gradient resistance component is canceled is calculated.

Here, the disturbance torque estimated value Td is a motor rotation speed ωm or a wheel speed ωw and a motor torque command value Tm *, using a vehicle model (details will be described later) that imitates the driving force transmission system of the vehicle. Estimated based on. However, for example, when the drive wheels are jacked up during maintenance of the vehicle, the parameters constituting the vehicle model are extremely different from the actual vehicle state. If the drive wheels rotate due to accelerator operation or other external force in this state, the drive wheels rotate without friction with the road surface, so the motor rotation speed or wheel speed is detected to be relatively high with respect to the motor torque. Will be done. As a result, the disturbance torque estimated value Td is erroneously estimated, and it is erroneously recognized that the vehicle is traveling on a downhill road, so that the gradient correction is executed in the direction (regeneration side) in which the motor outputs the braking torque. Then, since the motor rotation speed or the wheel speed is detected to be lower than the motor torque command value, it is erroneously estimated that the vehicle is traveling on an uphill road, and the motor is made to output the drive torque (power running). Gradient correction on the side) is executed.

In this way, when the drive wheels of the vehicle are jacked up, or when traveling on a low μ road such as an icy road surface, the frictional force acting between the wheels and the road surface is lower than during normal driving. Therefore, if the actual vehicle condition and the vehicle model are extremely different, the disturbance torque cannot be estimated accurately. In addition, not only the disturbance torque cannot be estimated accurately, but also the disturbance torque estimated value Td fluctuates abnormally positively and negatively due to repeated erroneous estimation from the downhill road to the uphill road or vice versa. Self-excited vibration may occur in the vehicle.

In order to suppress the self-excited vibration that may occur in this way, the control device for the electric vehicle according to the present embodiment determines whether or not the disturbance torque estimated value Td is an abnormal value, and determines whether or not the disturbance torque estimated value Td is an abnormal value. If is determined to be abnormal, the correction propriety determination process for canceling the gradient correction is executed. The configuration for executing the correction possibility determination process will be described below.

The disturbance estimation torque abnormality determining device 405 illustrated in FIG. 4 determines whether or not the disturbance torque estimated value Td is an abnormal value from the fluctuation frequency of the disturbance torque estimated value Td estimated by the disturbance torque estimator 402. .. When the disturbance estimation torque abnormality determining device 405 determines that the disturbance torque estimated value Td is an abnormal value, the gradient correction canceling flag is set to 1 and output to the disturbance correction torque setting device 406 in order to stop the gradient correction. To do. The details of the correction possibility determination process executed by the disturbance estimation torque abnormality determination device 405 will be described later.

The disturbance correction torque setting device 406 sets the disturbance correction torque according to the gradient correction stop flag, which is the output value of the disturbance estimation torque abnormality determining device 405. When the gradient disturbance correction stop flag is 0 (initial value), the disturbance torque estimated value Td is determined to be normal, so the disturbance torque estimated value Td is set to the disturbance correction torque as usual. When the gradient disturbance correction stop flag is 1, the disturbance torque estimated value Td is determined to be abnormal, so the disturbance correction torque is set to 0 in order to stop the gradient correction based on the gradient torque estimated value Td.

The adder 404 calculates the first torque target value Tm1 ^{* by adding the basic torque target value Tm0 *} calculated by the basic torque target value setter 401 and the disturbance correction torque. As a result, when the gradient disturbance correction stop flag is 0, the first torque target value Tm1 ^* for which the gradient correction is made based on the disturbance torque estimated value Td is calculated. When the gradient disturbance correction stop flag is set to 1 because the disturbance torque estimated value Td indicates an abnormal value, the gradient correction is not performed and the basic torque target value Tm0 ^* as the driver required torque is used as it is for the motor torque. It is set as the command value Tm ^*.

Subsequently, in the control device for the electric vehicle according to the present embodiment, the transmission characteristic Gp (s) from the motor torque Tm to the motor rotation speed ωm will be described. The transmission characteristic G _p (s) is used as a vehicle model that models the driving force transmission system of the vehicle when calculating the disturbance torque estimated value.

FIG. 6 is a diagram modeling a driving force transmission system of a vehicle, and each parameter in the figure is as shown below.
J _m : Electric motor inertia J _w : Drive wheel inertia M: Vehicle weight K _d : Drive system torsional rigidity K _t : Coefficient related to friction between tire and road surface N: Overall gear ratio r: Tire load radius ω _m : Motor rotation speed T _m : Torque target value ^{T m *}
T _d : Drive wheel torque F: Force applied to the vehicle V: Vehicle speed ω _w : Drive wheel angular velocity (wheel speed)
Then, from FIG. 6, the following equation of motion can be derived.

^{However, the asterisk (*} ) attached to the upper right of the code in the equations (1) to (3) represents the time derivative.

When the transmission characteristic Gp (s) from the motor torque Tm of the motor 4 to the motor rotation speed ωm is obtained based on the equations of motion represented by the equations (1) to (5), it is expressed by the following equation (6).

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

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

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

Subsequently, the details of the stop control process executed in step S203 will be described with reference to FIGS. 7 and 8.

<Stop control processing>
FIG. 7 is a block diagram for realizing the stop control process. The stop control process is performed using the motor rotation speed F / B torque setting device 701, the adder 703, and the torque comparator 704. The details of each configuration will be described below.

The motor rotation speed F / B torque setter 701 calculates the motor rotation speed feedback torque (hereinafter referred to as motor rotation speed F / B torque) Tω based on the detected motor rotation speed ωm. Details will be described with reference to FIG.

FIG. 8 is a diagram for explaining a method of calculating the motor rotation speed F / B torque Tω based on the motor rotation speed ωm. The motor rotation speed F / B torque setting device 701 includes a multiplier 801 and calculates the motor rotation speed F / B torque Tω by multiplying the motor rotation speed ωm by the gain Kvref. However, Kvref is a negative (minus) value required to stop the electric vehicle just before the electric vehicle is stopped, and is appropriately set based on, for example, experimental data. 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 increases.

Although the motor rotation speed F / B torque setting device 701 has been described as calculating the motor rotation speed F / B torque Tω by multiplying the motor rotation speed ωm by the gain Kvref, the regenerative torque with respect to the motor rotation speed ωm has been described. The motor rotation speed F / B torque Tω may be calculated by using a regenerative torque table in which the above is set, a damping rate table in which the attenuation rate of the motor rotation speed ωm is stored in advance, or the like.

The explanation will be continued by returning to FIG. The adder 703 adds the motor rotation speed F / B torque Tω calculated by the motor rotation speed F / B torque setter 701 and the disturbance correction torque which is the output value of the above-mentioned disturbance correction torque setter 406. The second torque target value Tm2 ^* is calculated by The disturbance correction torque is a value set according to the disturbance torque estimated value Td, and the details are as described above with reference to FIG.

Here, the details of the control block 504 shown in FIG. 5 will be described with respect to the disturbance torque estimated value Td. The control block 504 is a filter having a transmission characteristic of Hz (s), and the disturbance torque estimated value Td is calculated by inputting the output of the subtractor 503 and performing the filtering process.

The transmission characteristic Hz (s) will be described. By rewriting the equation (9), the following equation (10) is obtained. However, ζz, ωz, ζp, and ωp in the equation (10) are represented by the equation (11), respectively.

From the above, Hz (s) is represented by the following equation (12). However, ζ _c > ζ _z . Further, in order to enhance the vibration suppression effect in a deceleration scene accompanied by gear backlash, ζ _c > 1.

As described above, in the present embodiment, the disturbance torque is estimated by the disturbance observer as shown in FIG.

Here, as the disturbance, air resistance, modeling error due to fluctuation of vehicle mass due to the number of occupants and the load capacity, rolling resistance of tires, gradient resistance of the road surface, etc. can be considered, but the disturbance that becomes dominant just before the vehicle stops. The factor is gradient resistance. The disturbance factor differs depending on the operating conditions, but the disturbance torque estimator 402 ^{calculates the disturbance torque estimated value Td based on the motor torque command value Tm *} , the motor rotation speed ωm, and the vehicle model Gp (s). It is possible to estimate all the disturbing factors. As a result, as long as the above-mentioned vehicle model and the driving force transmission system of the actual vehicle are substantially the same, it is possible to realize a smooth stop from deceleration under any driving conditions.

The explanation will be continued by returning to FIG. ^{The adder 703 calculates the second torque target value Tm2 *} by adding the motor rotation speed F / B torque Tω calculated by the motor rotation speed F / B torque setter 701 and the disturbance correction torque. ..

The torque comparator 704 compares the magnitudes of the first torque target value Tm1 ^* and the second torque target value Tm2 ^* , and sets the torque target value having the larger value as the motor torque command value Tm ^*. While the vehicle is running, the second torque target value Tm2 ^* is smaller than the first torque target value Tm1 ^* , and when the vehicle decelerates and is about to stop (the vehicle speed or the speed parameter proportional to the vehicle speed is less than a predetermined value). , It becomes larger than the first torque target value Tm1 ^*. Therefore, if the first torque target value Tm1 ^* is larger than the second torque target value Tm2 ^* , the torque comparator 704 determines that the vehicle is about to stop and ^{sets the motor torque command value Tm *} to the first torque target value. Set to Tm1 ^*. Further, when the second torque target value Tm2 ^* becomes larger than the first torque target value Tm1 ^* , the torque comparator 704 determines that the vehicle is about to stop and ^{sets the motor torque command value Tm *} to the first torque target. The value Tm1 ^* is switched to the second torque target value Tm2 ^*. In order to maintain the stopped state, the second torque target value Tm2 ^* converges to positive torque on uphill roads, negative torque on downhill roads, and approximately zero on flat roads.

The details of the transmission characteristic G _p (s) and the stop control process have been described above. As described above, when the drive wheels of the vehicle are jacked up, parameters such as the vehicle weight constituting the vehicle model and the coefficient of friction with the road surface may be extremely different from the actual vehicle condition. In the present embodiment, the correction possibility determination process is executed in order to suppress the self-excited vibration that may occur due to the disturbance torque estimated value erroneously estimated in such a situation. Hereinafter, the details of the correction possibility determination process executed by the disturbance estimation torque abnormality determination device 405 (see FIG. 4) will be described.

FIG. 9 is a flowchart showing the flow of the correction possibility determination process in the first embodiment. The flow is programmed in the motor controller 2 to be repeatedly executed in a fixed cycle.

In step S801, the motor controller 2 detects the fluctuation frequency of the disturbance torque estimated value Td. The disturbance torque estimated value Td is calculated using the disturbance observer described with reference to FIG.

In the following step S802, the motor controller 2 determines whether or not the disturbance torque estimated value Td is abnormal from the fluctuation frequency of the detected disturbance torque estimated value Td.

Here, the disturbance torque estimated value Td is originally a value calculated according to the road surface gradient when the vehicle travels on the road surface. Further, the disturbance torque estimated value Td has a positive sign on the uphill road and a negative sign on the downhill road. Therefore, the abnormality of the disturbance torque estimated value Td can be detected based on the comparison between the positive and negative fluctuation frequencies of the sign of the disturbance torque estimated value Td and the road surface condition in which the vehicle actually travels. For example, on a road surface on which a normal vehicle travels, the change from an uphill road to a downhill road and vice versa is rarely repeated in one second. Therefore, if the positive / negative fluctuation frequency of the disturbance torque estimated value Td (hereinafter, simply referred to as the fluctuation frequency) is, for example, 1 Hz or more, the disturbance torque estimated value Td can be determined to be an abnormal value. Note that 1 Hz shown here is an example, and a frequency lower than or higher than that may be set as a frequency at which an abnormality of the disturbance torque estimated value Td can be determined.

In step S802, if the fluctuation frequency of the disturbance torque estimated value Td is 1 Hz or more, the motor controller 2 determines that the disturbance torque estimated value Td is an abnormal value, and determines whether or not the abnormality continues for a predetermined time. Therefore, the process of step S803 that follows is executed. If the fluctuation frequency of the disturbance estimated torque is smaller than 1 Hz, the process of step S804 is executed in order to execute the gradient correction.

In step S803, the motor controller 2 determines whether or not the fluctuation frequency abnormality of the disturbance torque estimated value Td continues for a predetermined time or longer. This step is a process for preventing the gradient correction from being unnecessarily stopped when it is erroneously determined that the disturbance torque estimated value Td is an abnormal value. Further, for example, even if the disturbance torque estimated value Td shows an abnormal vibration, if the vibration converges immediately, it is not always necessary to stop the gradient correction. Even in such a case, it is possible to prevent the gradient correction from being unnecessarily stopped by executing the process of this step. The predetermined time here is set according to, for example, a value obtained by previously measuring the damping time when the vibration of the estimated disturbance torque value that may occur when the vehicle is raised is converged to 0. When the motor controller 2 determines that the fluctuation frequency abnormality has continued for a predetermined time or longer, the motor controller 2 executes the process of step S805 that follows in order to stop the gradient correction. When it is determined that the fluctuation frequency abnormality does not continue for a predetermined time or more, the process of step S801 is repeatedly executed in order to calculate the current value of the disturbance torque estimated value Td.

Here, the control block that realizes the abnormality determination of the fluctuating frequency executed in steps S801 to S803 will be described with reference to FIGS. 10 and 11.

10 and 11 are control block diagrams showing an example of the configuration of the disturbance estimation torque abnormality determining device 405 (see FIG. 5) that executes the abnormality determination of the fluctuating frequency. The disturbance estimation torque abnormality determining device 405 includes, for example, a half-cycle counter 810 shown in FIG. 10, a frequency component extraction filter 820 shown in FIG. 11, a frequency comparator 830, and a timer 840.

The half-cycle counter 810 is composed of a sign determination device 811, an edge detector 812, and a timer counter 813. A disturbance torque estimated value Td is input, and a half-cycle time (time after crossing 0) of the disturbance torque estimated value Td is input. ) Is detected. More specifically, the sign determination device 811 determines the positive / negative of the disturbance torque estimated value Td, and the edge detector 812 detects the rising edge and the falling edge of the disturbance torque estimated value Td. Then, the timer counter 813 detects the time after straddling 0 between the positive or negative rising edge and the falling edge of the disturbance torque estimated value Td. The half-cycle time of the disturbance torque estimated value detected in this way is output to the frequency component extraction filter 820 (see FIG. 11).

The frequency component extraction filter 820 shown in FIG. 11 is composed of a lower limit comparator 821, an upper limit comparator 823, and an AND circuit 824, and inputs a half cycle time from the timer counter 813 to perform filtering processing. To calculate the half-cycle time near resonance.

The lower limit comparator 821 compares the half cycle time with the preset half cycle time lower limit value, and cuts the half cycle time equal to or less than the frequency fluctuation accompanying the road surface gradient change that can be normally detected during normal driving.

The upper limit comparator 823 compares the half-cycle time with the preset half-cycle time upper limit value, and cuts high-frequency noise generated by chattering or the like. However, since the fluctuation frequency at the time of jacking up the vehicle can be specified in advance by experiments or the like, the comparison value between the lower limit comparator 821 and the upper limit comparator 823 is set to a value that extracts only the vicinity value of the fluctuation frequency. Is also good.

Then, the AND circuit 824 extracts a frequency component (half cycle near resonance) of the half cycle time lower limit value or more and the half cycle time upper limit value or less from the half cycle time output from the half cycle counter 810, and the frequency comparator 830. Output to.

The frequency comparator 830 counts the half period near the resonance to calculate the fluctuation frequency of the disturbance torque estimated value Td, and determines whether or not the fluctuation frequency of the disturbance torque estimated value Td is equal to or higher than a predetermined frequency. The predetermined frequency is set to, for example, 1 Hz as described above. Then, if the fluctuation frequency of the disturbance estimated torque is equal to or higher than a predetermined value, it is determined that the disturbance estimated torque is an abnormal value, and a flag (frequency abnormality flag) indicating that the disturbance estimated torque is an abnormal value is set in the timer 840. Output.

The timer 840 determines whether or not the fluctuation frequency abnormality of the disturbance torque estimated value Td continues for a predetermined time by counting the duration of the frequency abnormality flag. When the frequency abnormality flag continues for a predetermined time or longer, the flag for canceling the gradient correction (gradient correction cancel flag) is set to 1, and the flag is output to the disturbance correction torque setter 406 shown in FIG.

With the above configuration, the disturbance estimation torque abnormality determining device 405 can determine whether or not the fluctuation frequency of the disturbance torque estimation value Td is an abnormal value.

Go back to the flow and continue the explanation. In step S805, the disturbance torque estimated value is determined to be an abnormal value in step S802, and it is determined in step S803 that the abnormality of the disturbance torque estimated value Td has continued for a predetermined time. Therefore, the motor controller 2 sets the disturbance correction torque to 0. By doing so, the gradient correction is stopped and the correction approval / disapproval determination process is terminated.

On the other hand, in step S804, since the disturbance torque estimated value is determined to be a normal value from the fluctuation frequency, the disturbance torque estimated value Td as the disturbance correction torque is set in order to execute the gradient correction with respect to the motor torque command value. After the disturbance torque estimated value Td is set as the disturbance correction torque, the processing of the subsequent step S806 is executed.

In step S806, the motor controller 2 corrects the gradient by adding the disturbance torque estimated value Td as the disturbance correction torque to the basic torque target value Tm0 ^{* as the driver required torque.} After the gradient correction is executed in this way, the motor controller 2 ends the correction possibility determination process.

The effect of applying the control device for the electric vehicle of the first embodiment described above to the electric vehicle will be described with reference to FIG.

FIG. 12 is a time chart illustrating an example of the control result by the control device of the electric vehicle according to the present embodiment. FIG. 12 shows the control results in a situation where the accelerator is operated by mistake while the vehicle is jacked up during maintenance of the vehicle. From the top, the accelerator opening, the driver required torque, and the disturbance torque estimated value are shown. It represents Td, frequency abnormality flag (0: normal, 1: abnormal), disturbance correction stop flag (0: disturbance correction continuation, 1: disturbance correction stop), and motor torque.

When the accelerator opening degree increases, the basic torque target value as the driver required torque is calculated according to the accelerator opening degree (time t1). Then, due to the gradient correction, the motor torque is generated according to the motor torque command value obtained by adding the disturbance torque estimated value to the basic torque target value, and the motor 4 rotates. Here, since the vehicle is jacked up, the disturbance torque estimation is a result of the extreme difference between the equation of motion (see Equations 1 to 5) used for calculating the disturbance torque estimation value and the actual vehicle motion. The value is misestimated. Then, the torque target value is calculated based on the value obtained by adding the erroneously estimated disturbance torque estimated value, and the motor rotation speed corresponding to the motor torque generated based on the torque target value is fed back. The erroneous estimation of the disturbance torque command value continues, and the disturbance torque estimated value and the motor torque vibrate.

Here, when the fluctuation frequency of the disturbance torque estimated value exceeds a predetermined value (for example, 1 Hz), the fluctuation frequency is determined to be abnormal, and the frequency abnormality flag becomes 1 (time t2). After that, the vibration of the estimated disturbance torque value does not converge even after a lapse of a predetermined time, and the frequency abnormality flag remains 1, so that the disturbance correction enable / disable flag becomes 1 (time t3). As a result, the output value of the disturbance torque estimated value as the disturbance correction torque is fixed to 0, and the gradient correction is stopped. As a result, the motor torque is attenuated and converges to the driver required torque, so that the self-excited vibration of the vehicle body is suppressed.

As described above, the control device for the electric vehicle of the first embodiment is a control device that functions as a traveling drive source and realizes a control method for the electric vehicle including a motor that gives a regenerative braking force to the vehicle. The control device calculates a torque target value for outputting the control drive torque according to the accelerator operation amount to the motor, and acts on the motor as a resistance corresponding to the road surface gradient estimated based on the wheel speed and the torque target value. Estimate the disturbance torque. Then, a correction for removing the disturbance torque component from the torque target value is executed, the motor is controlled based on the corrected torque target value, and when the fluctuation frequency of the disturbance torque becomes equal to or higher than a predetermined frequency, the correction is stopped. As a result, when the disturbance torque estimated value Td is determined to be an abnormal value, the gradient correction is stopped, so that the self-excited vibration of the vehicle body generated due to the erroneous estimation of the disturbance torque estimated value Td is suppressed. can do.

Further, in the control device of the electric vehicle of the first embodiment, the disturbance torque (disturbance torque estimated value) is estimated as a positive value on an uphill road and a negative value on a downhill road, and the gradient correction is a torque target value and a disturbance. It is executed by adding the torque estimated value Td. As a result, in normal driving, it is possible to calculate the motor torque command value in which the gradient resistance corresponding to the road surface gradient is canceled with respect to the driver required torque corresponding to the accelerator opening degree of the driver.

[Second Embodiment]
In the second embodiment, the method of processing the disturbance correction torque when the estimated value of the disturbance torque is determined to be an abnormal value is mainly different from that of the first embodiment.

FIG. 13 is a control block diagram illustrating details of a method for calculating the first torque target value Tm1 ^{* in the present embodiment.} A configuration having the same function as that of the first embodiment is designated by the same reference numerals as those in FIG. 4, and the description thereof will be omitted.

The disturbance correction torque setting device 940 in the present embodiment is used to estimate the disturbance torque shown in FIG. 4 when the disturbance correction stop flag output from the disturbance estimation torque abnormality determining device 405 is 1 (the disturbance torque estimated value Td is an abnormal value). The second disturbance estimated value calculated by a means (second means) different from that of the device 402 is set as the disturbance correction torque.

The second disturbance estimation value is a road surface gradient estimation value calculated based on the detection value of the front-rear G sensor 15, and is a disturbance calculated without using a vehicle model that imitates the driving force transmission system of the vehicle. The estimated value is shown. That is, the second means is a means that can correctly detect the slope of the vehicle (the tilted state of the vehicle) even when the actual vehicle state and the vehicle model deviate from each other, such as when the vehicle body is jacked up. is there. The second disturbance estimation value detected in this way is, in principle, a constant value unless the tilted state of the vehicle body changes.

As a result, when the disturbance torque estimated value Td is determined to be an abnormal value, the motor 4 is controlled according to the gradient-corrected torque command value based on the second disturbance estimated value of a constant value, so that the disturbance torque is estimated. It is possible to suppress the self-excited vibration of the vehicle body that may occur in response to the vibration caused by the erroneous estimation of the value Td.

Hereinafter, the details of the correction possibility determination process in the present embodiment will be described with reference to FIG.

FIG. 14 is a flowchart showing the flow of the correction possibility determination process in the second embodiment. The flow is programmed in the motor controller 2 to be repeatedly executed in a fixed cycle.

In step S901, the motor controller 2 detects the disturbance torque estimated value (first disturbance estimated value) by the first means. The first means here is the same as the estimation means in the first embodiment, and specifically, the disturbance torque estimated value Td is calculated by using the disturbance observer described with reference to FIG. Shown. The motor controller 2 acquires the disturbance torque estimated value Td as the first disturbance estimated value, and then executes the processing of the subsequent step S902.

In step S902, the motor controller 2 determines whether or not the first disturbance estimation value is abnormal. Here, as in the first embodiment, it is determined whether or not the fluctuation frequency of the first disturbance estimated value is a predetermined value (for example, 1 Hz) or more. If the fluctuation frequency of the first disturbance estimated value is 1 Hz or more, and if the first disturbance estimated value is determined to be an abnormal value, in order to determine whether or not the abnormal value continues for a predetermined time, Subsequent processing in step S903 is executed. If the fluctuation frequency of the first disturbance estimate is less than 1 Hz, the process of step S904 is executed in order to execute the gradient correction based on the first disturbance estimate.

In step S904, since the first disturbance estimated value is determined to be a normal value from the fluctuation frequency, the disturbance torque estimated value Td as the first disturbance estimated value is disturbed in order to execute the gradient correction with respect to the basic torque target value. Set to the correction torque. After the disturbance torque estimated value Td is set to the disturbance correction torque, the motor controller 2 executes the subsequent process of step S907.

On the other hand, in step S903, the motor controller 2 determines whether or not the fluctuation frequency abnormality of the disturbance torque estimated value Td continues for a predetermined time. This step is a process for preventing the gradient correction from being unnecessarily stopped when it is erroneously determined that the disturbance torque estimated value Td is an abnormal value. If the fluctuation frequency abnormality of the disturbance torque estimated value Td does not continue for a predetermined time, the process of step S901 is repeatedly executed. When it is determined that the fluctuation frequency abnormality of the disturbance torque estimated value Td has continued for a predetermined time, the subsequent process of step S906 is executed.

In step S905, since the first disturbance estimated value is determined to be an abnormal value, the motor controller 2 acquires the second disturbance estimated value in order to execute the gradient correction by the second means. When the second disturbance estimation value is acquired, the processing of the following step S907 is executed in order to perform the gradient correction by the second disturbance estimation value.

In step S907, if the first disturbance estimated value is normal, it is based on the disturbance correction torque set in step S903 (first means), and if the first disturbance estimated value is abnormal, it is based on the disturbance correction torque set in step S904 (second means). Gradient correction is executed, and the correction approval / disapproval determination process is completed.

The effect of applying the control device for the electric vehicle of the second embodiment described above to the electric vehicle will be described with reference to FIG.

FIG. 15 is a time chart illustrating an example of the control result by the control device of the electric vehicle according to the second embodiment. FIG. 15 shows the control results in a situation where the accelerator is operated by mistake while the vehicle is jacked up during maintenance of the vehicle. From the top, the accelerator opening, the driver required torque, and the first disturbance are shown. Estimated value (disturbance torque estimated value Td), second disturbance estimated value, frequency abnormality flag (0: normal, 1: abnormal), disturbance correction switching flag (0: first disturbance estimated value, 1: second disturbance Estimated value), represents the motor torque.

When the accelerator opening degree increases, the basic torque target value as the driver required torque is calculated according to the accelerator opening degree (time t1). Here, since the vehicle is jacked up, the equation of motion (see Equations 1 to 5) used to calculate the disturbance torque estimated value Td (first disturbance estimated value) and the actual vehicle motion are As a result of the extreme differences, the first disturbance estimate is erroneously estimated. Then, the torque target value is calculated based on the value obtained by adding the erroneously estimated disturbance torque estimated value, and the motor rotation speed corresponding to the motor torque generated based on the torque target value is fed back. The erroneous estimation of the disturbance torque command value continues, and the disturbance torque estimated value and the motor torque vibrate.

Here, when the fluctuation frequency of the first disturbance estimation value exceeds a predetermined value (for example, 1 Hz), the fluctuation frequency is determined to be abnormal, and the frequency abnormality flag is set to 1 (time t2). After that, even after the elapse of a predetermined time, the vibration of the estimated disturbance torque value has not converged, and the frequency abnormality flag remains 1, so that the disturbance correction switching flag becomes 1 (time t3).

As a result, the gradient correction is switched to the disturbance correction based on the second disturbance estimation value according to the disturbance correction switching flag. The second disturbance estimation value is a value calculated based on the front-rear G sensor, and is a constant value gradient value based on the actual state of the vehicle. Therefore, since the second disturbance estimation value is added to the driver required torque having a value of 0, the motor torque converges to the second disturbance estimation value of a constant value, and the self-excited vibration of the vehicle body is suppressed. To.

As described above, in the control device for the electric vehicle of the second embodiment, the estimated disturbance torque estimated value is set as the first disturbance estimated value (first disturbance torque), and is acquired by a means different from the first disturbance estimated value. The disturbance estimated value is set as the second disturbance estimated value (second disturbance torque), and the correction for removing the first disturbance torque component from the torque target value is executed based on the estimated first disturbance estimated value. .. Then, when the fluctuation frequency of the first disturbance estimation value becomes equal to or higher than a predetermined frequency, the gradient correction is stopped and the second disturbance torque component is removed from the torque target value based on the second disturbance estimation value. Perform correction (gradient correction). As a result, when the disturbance torque estimated value Td is determined to be an abnormal value, the gradient correction is stopped, and the gradient correction is executed based on the second disturbance estimated value which is a constant value. Therefore, the disturbance torque estimated value Td It is possible to suppress the self-excited vibration of the vehicle body caused by the false estimation of.

Further, according to the control device for the electric vehicle of the second embodiment, the second disturbance estimation value is calculated based on the output value of the sensor (front-rear G sensor 15) capable of detecting the tilted state of the vehicle in the front-rear direction. To. This makes it possible to detect the tilted state of the vehicle body even when the equation of motion of the vehicle (see Equations 1 to 5) and the actual vehicle motion are extremely different, such as when the vehicle is jacked up. ..

[Third Embodiment]
In the correction possibility determination process in the third embodiment, the correction possibility is determined after determining the state of the vehicle in more detail as compared with the first and second embodiments.

FIG. 16 is a control block diagram illustrating details of the method for calculating the motor torque command value in the present embodiment. The present embodiment is characterized in that it further includes a maximum value setting device 1030, a disturbance correction torque setting device 1040, and a stopped state determination device 1050. The configurations that function in the same manner as in the first and second embodiments are designated by the same reference numerals as those in FIGS. 4 and 13, and the description thereof will be omitted.

The disturbance torque estimated value Td as the first disturbance estimated value and the second disturbance estimated value acquired in the same manner as described in the second embodiment are input to the maximum value setter 1030. Then, the maximum value setting device 1030 compares the absolute value of the first disturbance estimated value with the absolute value of the second disturbance estimated value, selects the disturbance estimated value indicating the larger value, and selects the selected one. The disturbance estimated value of is output to the disturbance correction torque setting device 1040. For example, if the absolute value of the second disturbance estimation value is larger than the absolute value of the first disturbance estimation value, the second disturbance estimation value is output to the disturbance correction torque setter 1040.

The stopped state determination device 1050 determines whether or not the vehicle is stopped, and if the vehicle is stopped, whether or not the stop is due to the friction brake, and outputs the determination result to the disturbance correction torque setting device 1040. .. The method for determining whether or not the vehicle is stopped is not particularly limited. For example, it may be determined from the driven wheel speed of the vehicle, the position information of the vehicle by GPS, and the like.

Then, the disturbance correction torque setting device 1040 has a disturbance correction stop flag of 1 (disturbance estimated torque is an abnormal value) output from the disturbance estimation torque abnormality determining device 405, and the vehicle is not stopped, or If the disturbance correction stop flag is 1, and the vehicle is stopped by a braking force other than the friction brake such as the braking torque of the motor, the gradient correction is stopped by setting the disturbance correction torque to 0. ..

Further, the disturbance correction torque setting device 1040 has an output value of the maximum value setting device 1030 when the disturbance correction stop flag is 1 (disturbance estimated torque is an abnormal value) and the vehicle is stopped by the friction brake. Is set to the disturbance correction torque. As a result, the fluctuation of the disturbance torque estimated value Td converges due to the stoppage due to the friction brake, and the absolute value of the first disturbance estimated value is compared with the absolute value of the second disturbance estimated value, and the larger value is used. Since the disturbance estimated value is selected as the disturbance correction torque, the self-excited vibration of the vehicle can be suppressed, and the stopped state of the vehicle can be maintained more reliably.

When the disturbance correction stop flag output from the disturbance estimation torque abnormality determining device 405 is 0 and the first disturbance estimation value is a normal value, the disturbance correction torque setting device 1040 uses the first disturbance estimation. Set the value to the disturbance correction torque.

FIG. 17 is a flowchart showing the flow of the correction possibility determination process in the third embodiment. The flow is programmed in the motor controller 2 to be repeatedly executed in a fixed cycle.

In step S1001, the motor controller 2 acquires the disturbance estimated value (first disturbance estimated value) by the first means. The first disturbance estimated value here indicates a disturbance torque estimated value Td calculated by using the disturbance observer described with reference to FIG. 5 in the first embodiment. After acquiring the first disturbance estimation value, the motor controller 2 executes the subsequent process of step S1002.

In step S1002, the motor controller 2 determines whether or not the first disturbance estimation value is abnormal. Here, as in the first and second embodiments, it is determined whether or not the fluctuation frequency of the first disturbance estimated value is a predetermined value (for example, 1 Hz) or more. If the fluctuation frequency of the first disturbance estimated value is 1 Hz or more, the first disturbance estimated value is determined to be an abnormal value, and in order to determine whether or not the abnormal value continues for a predetermined time, the following step S1003 Executes the processing of. If the first disturbance estimated value is not determined to be an abnormal value, the process of step S1010 is executed in order to execute the gradient correction based on the first disturbance estimated value.

In step S1010, since the first disturbance estimated value is determined to be a normal value from the fluctuation frequency, the first disturbance estimated value is set to the disturbance correction torque in order to execute the gradient correction. After the first disturbance estimation value is set as the disturbance correction torque, the motor controller 2 executes the gradient correction based on the first disturbance estimation value in the subsequent step S1009.

On the other hand, in step S1003, the motor controller 2 determines whether or not the fluctuation frequency abnormality of the first disturbance estimated value continues for a predetermined time. This step is a process for preventing the gradient correction from being unnecessarily stopped when it is erroneously determined that the disturbance torque estimated value Td is an abnormal value. If the fluctuation frequency abnormality of the first disturbance estimated value does not continue for a predetermined time, the process of step S1001 is repeatedly executed. When it is determined that the fluctuation frequency abnormality of the disturbance torque estimated value Td has continued for a predetermined time, the subsequent process of step S1004 is executed.

In step S1004, the motor controller 2 determines whether or not the vehicle is in a stopped state. Here, when it is determined that the vehicle is not stopped, the first torque estimation value is an abnormal value, and the vehicle is in a moving state. Since it can be determined that such a scene is not at least during normal driving, the gradient correction is stopped. Therefore, when it is determined that the vehicle is not stopped in this step, the motor controller 2 executes the process of step S1006 in order to stop the gradient correction. When it is determined that the vehicle is stopped, the process of the following step S1005 is executed in order to determine whether or not the vehicle is stopped by the friction brake 13.

In step S1005, it is determined whether or not the vehicle is stopped by the friction brake 13. Whether or not the vehicle is stopped by the friction brake 13 can be determined from information such as the brake fluid pressure and the state of the parking brake. Here, when the first torque estimated value is an abnormal value and it is determined that the vehicle is stopped by the friction brake 13, the following step S1007 for acquiring the disturbance estimated value by the second means is obtained. Processing is executed. When it is determined that the vehicle is not stopped by the friction brake 13, it is presumed that the vehicle is stopped by the controlling driving force of the motor and the driving wheels are easily rotated by the external force. Vibrations can easily be triggered. Therefore, the motor controller 2 executes the process of step S1006 in order to stop the gradient correction.

In step S1006, the motor controller 2 stops the gradient correction according to the NO determination in step S1004 or step S1005, and ends the correction possibility determination process.

In step S1007, the second disturbance correction torque (second disturbance estimated value) is acquired. The method of acquiring the second disturbance estimated value is the same as that described in the description of the second embodiment. Then, the motor controller 2 executes the subsequent process of step S1008 in order to select the disturbance correction torque from the first disturbance estimated value and the second disturbance estimated value.

In step S1008, the motor controller 2 selects the disturbance correction torque. Specifically, the absolute value of the first disturbance estimated value calculated in step S1001 is compared with the absolute value of the second disturbance estimated value, and the larger value is selected as the disturbance correction torque.

In this step, the vehicle body is stopped by the friction brake and the motor rotation speed becomes 0, so that the frequency fluctuation caused by the erroneous estimation of the first disturbance estimation value converges. At this time, by selecting the disturbance correction torque as described above, it is possible to calculate the disturbance correction torque in which the positive and negative values are switched and do not fluctuate as in the first estimated value of the disturbance before it converges to 0. it can. After the disturbance correction torque is selected, the motor controller 2 executes the subsequent process of step S1009 in order to execute the gradient correction based on the disturbance correction torque.

In step S1009, the gradient correction based on the disturbance estimated value (disturbance correction torque) selected in step S1008 is executed, and the correction possibility determination process is completed.

The effect of applying the control device for the electric vehicle of the third embodiment described above to the electric vehicle will be described with reference to FIG.

FIG. 18 is a time chart illustrating an example of the control result by the control device of the electric vehicle according to the present embodiment. FIG. 18 shows the control results in a situation where the vehicle is jacked up during maintenance of the vehicle, the accelerator is operated by mistake, and the vehicle is stopped by the braking force of the friction brake. , Accelerator opening, driver required torque, disturbance estimated value (solid line: first disturbance estimated value (disturbed torque estimated value Td), dotted line: second disturbance estimated value), frequency abnormality flag (0: normal) , 1: Abnormal), disturbance correction selection flag, and motor torque. When the disturbance correction selection flag is 0, the first disturbance estimation value is set to the disturbance correction torque, and when the disturbance correction selection flag is 1, the first disturbance estimation value and the second disturbance estimation value are absolute. It is assumed that the disturbance estimation value having the larger value is set to the disturbance correction torque.

When the accelerator opening degree increases, the motor torque command value as the driver required torque is calculated according to the accelerator opening degree (time t1). Here, since the vehicle is jacked up, the equation of motion (see Equations 1 to 5) used to calculate the disturbance torque estimated value Td (first disturbance estimated value) and the actual vehicle motion are As a result of the extreme differences, the first disturbance estimate is erroneously estimated. Then, the torque target value is calculated based on the value obtained by adding the erroneously estimated disturbance torque estimated value, and the motor rotation speed corresponding to the motor torque generated based on the torque target value is fed back. The erroneous estimation of the disturbance torque command value continues, and the disturbance torque estimated value and the motor torque vibrate.

Here, when the fluctuation frequency of the first disturbance estimation value exceeds a predetermined value (for example, 1 Hz), the fluctuation frequency is determined to be abnormal, and the frequency abnormality flag is set to 1 (time t2). After that, even after a lapse of a predetermined time, the vibration of the estimated disturbance torque has not converged, the frequency abnormality flag remains 1, and the vehicle is stopped by the braking force of the friction brake. Therefore, the disturbance correction is selected. The flag becomes 1 (time t3).

As a result, according to the disturbance correction selection flag, the absolute value of the first disturbance estimation value and the absolute value of the second disturbance estimation value are compared, and the larger value is selected as the disturbance correction torque. As a result, the fluctuation of the first disturbance estimated value converges due to the stoppage due to the friction brake, and the absolute value of the first disturbance estimated value is compared with the absolute value of the second disturbance estimated value, and the larger value is obtained. Since the disturbance estimated value of is selected as the disturbance correction torque, it is possible to avoid the disturbance correction torque from fluctuating to positive or negative, suppress the self-excited vibration of the vehicle, and maintain the stopped state of the vehicle.

As described above, in the control device for the electric vehicle of the third embodiment, the estimated disturbance torque is used as the first disturbance estimation value, and the disturbance estimation value acquired by a means different from the first disturbance estimation value is used as the second disturbance estimation value. Gradient correction is performed to remove the first disturbance torque component from the ^{basic torque target value Tm0 *} based on the estimated first disturbance estimated value. Then, it is determined whether or not the vehicle is stopped by the braking force of the friction brake, the fluctuation frequency of the first disturbance estimation value becomes equal to or higher than a predetermined frequency, and the vehicle is stopped by the braking force of the friction brake. If not, the gradient correction is stopped. If the fluctuation frequency of the first disturbance estimation value is equal to or higher than a predetermined frequency and the vehicle is stopped due to the braking force of the friction brake, the gradient correction based on the first disturbance estimation value is stopped. At the same time, the absolute value of the first disturbance estimation value is compared with the absolute value of the second disturbance estimation value, and the disturbance torque component is obtained from the basic torque command value based on the disturbance torque having the larger absolute value. Perform the correction to remove.

As a result, if the disturbance torque estimated value Td is determined to be an abnormal value and the vehicle is not stopped by the friction brake, the gradient correction is stopped, so that the disturbance torque estimated value Td vibrates. It is possible to suppress the self-excited vibration of the vehicle caused by it.

Further, even when the disturbance torque estimated value Td is determined to be an abnormal value and the vehicle is stopped by the friction brake, the larger disturbance torque estimated value is selected as the disturbance correction torque. Therefore, it is possible to avoid the disturbance correction torque from fluctuating to positive and negative, suppress the self-excited vibration of the vehicle, and maintain the stopped state of the vehicle.

Although the control device for the electric vehicle according to the first to third embodiments has been described above, the present invention is not limited to the above-described embodiment. For example, in the above description, when the accelerator operation amount is equal to or less than a predetermined value and the electric vehicle is about to stop, the rotation speed of the electric motor 4 decreases and the estimated disturbance torque after correcting the ^{motor torque command value Tm *.} It has been described that the stop control for converging to Td (disturbance correction torque) is executed. However, since speed parameters such as wheel speed, vehicle body speed, and drive shaft rotation speed are proportional to the rotation speed of the electric motor 4, the motor torque command value is reduced as the speed parameter is proportional to the rotation speed of the electric motor 4. Tm ^* may be converged to the disturbance torque estimated value Td. Further, in the first place, the above-mentioned stop control does not necessarily have to be executed just before the vehicle stops, and the stop control process according to step S203 in FIG. 2 may be deleted.

Further, in the description of the first and third embodiments, it has been explained that the disturbance correction torque is set to zero when the gradient correction is stopped, but it is not always necessary to set it to zero, and the current disturbance torque estimated value Td is currently set to zero. A value corrected so as to gradually converge to zero from the value may be set as the disturbance correction torque.

Further, in the disturbance estimation torque abnormality determining device 405, the determination as to whether or not the disturbance torque estimated value Td is an abnormal value does not necessarily have to be determined based on the fluctuation frequency of the disturbance torque estimated value Td as described above. For example, the absolute value amplitude of the disturbance torque estimated value Td may be detected, and it may be determined whether or not the disturbance torque estimated value Td is an abnormal value based on the gradient change that can be detected from the amplitude. Specifically, for example, it can be determined by the control block configuration shown in FIGS. 19 and 20 as an example.

The signal extraction filter 1100 shown in FIG. 19 is composed of a high-pass filter 1101 and a low-pass filter 1102. By inputting a disturbance torque estimated value and performing filtering processing, a resonance vicinity value of the disturbance torque estimated value Td is performed. Is extracted. The cutoff frequency of the high-pass filter 1101 is set to, for example, 1 Hz as described in the description of the first embodiment. The low-pass filter 1102 removes high-frequency noise components. However, since the fluctuation frequency when the vehicle is raised can be specified in advance by experiments or the like, a bandpass filter that extracts only the vicinity value of the fluctuation frequency can be configured by the high-pass filter 1101 and the low-pass filter 1102. good. As a result, it is possible to extract a value near the fluctuation frequency (value near the disturbance torque resonance) that can be determined to be abnormal in the disturbance torque estimated value.

Then, the rate of change of the value near the disturbance torque resonance is detected, and if it is equal to or more than a predetermined rate of change, it can be determined that the disturbance torque is abnormal. As the predetermined rate of change here, a rate of change in gradient that cannot be achieved on a normal road surface is set. For example, on a road surface on which a normal vehicle travels, there is almost no sudden change from a flat road to a slope road having an inclination angle of 50 ° or more. Therefore, when the rate of change of the disturbance correction torque corresponds to, for example, a gradient change rate of 50 ° or more, the disturbance estimation torque may be determined to be an abnormal value. Then, as described in FIGS. 10 and 11, when the timer 1300 determines that the abnormality has continued for a predetermined time, the gradient correction stop flag is set to 1.

The determination of whether or not the above-mentioned abnormality of the disturbance torque estimated value Td has continued for a predetermined time may be omitted. That is, referring to the flowcharts used in the description of the first to third embodiments, step S803 shown in FIG. 9, step S903 shown in FIG. 14, and step S1003 shown in FIG. 17 may be omitted.

2 ... Motor controller (controller)
4 ... Motor

Claims (6)

It is a control method for an electric vehicle equipped with a motor that functions as a traveling drive source and gives a regenerative braking force to the vehicle.
A torque target value for outputting the control drive torque according to the accelerator operation amount to the motor is calculated.
The disturbance torque acting on the motor is estimated as a resistance corresponding to the road surface gradient estimated based on the wheel speed and the torque target value.
A correction for canceling the disturbance torque component is executed from the torque target value, and the correction is performed.
The motor is controlled based on the corrected torque target value, and the motor is controlled.
When the fluctuation frequency of the disturbance torque becomes equal to or higher than a predetermined frequency, the correction is stopped.
A method of controlling an electric vehicle, which is characterized in that. The disturbance torque is estimated as a positive value on an uphill road and a negative value on a downhill road.
The correction is performed by adding the torque target value and the estimated disturbance torque.
The method for controlling an electric vehicle according to claim 1. The estimated disturbance torque is used as the first disturbance torque.
The disturbance torque acquired by a means different from the first disturbance torque is defined as the second disturbance torque.
Based on the estimated first disturbance torque, a correction for removing the first disturbance torque component from the torque target value is executed.
When the fluctuation frequency of the first disturbance torque becomes equal to or higher than a predetermined frequency, the correction is stopped and the second disturbance torque component is removed from the torque target value based on the second disturbance torque. Perform correction,
The method for controlling an electric vehicle according to claim 1 or 2. The estimated disturbance torque is used as the first disturbance torque.
The disturbance torque acquired by a means different from the first disturbance torque is defined as the second disturbance torque.
Based on the estimated first disturbance torque, a correction for removing the first disturbance torque component from the torque target value is executed.
Judge whether the vehicle is stopped by the braking force of the friction brake,
If the fluctuation frequency of the first disturbance torque is equal to or higher than a predetermined frequency and the vehicle is not stopped due to the braking force of the friction brake, the correction is stopped.
When the fluctuation frequency of the first disturbance torque is equal to or higher than the predetermined frequency and the vehicle is stopped by the braking force of the friction brake, the correction is stopped and the first disturbance torque is stopped. The absolute value of the second disturbance torque is compared with the absolute value of the second disturbance torque, and a correction for removing the disturbance torque component from the torque target value is executed based on the disturbance torque having the larger absolute value.
The method for controlling an electric vehicle according to claim 1 or 2. The second disturbance torque is calculated based on the output value of the sensor capable of detecting the tilted state of the vehicle in the front-rear direction.
The method for controlling an electric vehicle according to claim 3 or 4. It is a control device for an electric vehicle having a motor that functions as a traveling drive source and gives a regenerative braking force to the vehicle and a controller that controls the vehicle system.
The controller
A torque target value for outputting the control drive torque according to the accelerator operation amount to the motor is calculated.
The disturbance torque acting on the motor is estimated as a resistance corresponding to the road surface gradient estimated based on the wheel speed and the torque target value.
A correction for canceling the disturbance torque component is executed from the torque target value, and the correction is performed.
The motor is controlled based on the corrected torque target value, and the motor is controlled.
When the fluctuation frequency of the disturbance torque becomes equal to or higher than a predetermined frequency, the correction is stopped.
A control device for an electric vehicle.

Images