JP7107435B2 - ELECTRIC VEHICLE CONTROL METHOD AND ELECTRIC VEHICLE CONTROL SYSTEM - Google Patents

Description

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

2. Description of the Related Art An electric vehicle equipped with a regenerative brake control device that obtains braking force through regenerative operation of an electric motor is known.

JP6135775B proposes such an electric vehicle control method, particularly a regenerative brake control method. Specifically, in JP6135775B, in a scene in which an electric vehicle is decelerated and stopped by the regenerative braking force of the motor, the speed parameter proportional to the running speed (such as the rotation speed of the electric motor) decreases to a predetermined value before and after the motor A control method for switching the torque command value has been proposed. According to this control method, in a scene in which the electric vehicle decelerates, the motor torque command value is set so as to suppress changes in acceleration (deceleration), thereby suppressing longitudinal vibration of the vehicle body when the vehicle is stopped. .

However, even if the stop control is performed to set the motor torque command value so as to suppress the change in deceleration as described above, there is a problem that depending on the conditions of the traveling road, the passenger may feel a sudden stop. rice field.

In view of such circumstances, it is an object of the present invention to provide an electric vehicle control method and an electric vehicle control system capable of suppressing the sudden stop feeling given to the passenger when the vehicle stops.

According to one aspect of the present invention, there is provided an electric vehicle control method that executes stop control for decelerating and stopping an electric vehicle by regenerative braking force of an electric motor. The stop control includes first jerk adjustment processing for adjusting the jerk of the electric vehicle to a predetermined upper limit value or less when the vehicle speed of the electric vehicle exceeds the threshold vehicle speed, and control when the vehicle speed is the threshold vehicle speed or less. , a second jerk adjustment process for adjusting the jerk so that the deceleration and jerk of the electric vehicle take a profile in which they asymptotically decrease to 0 as the vehicle speed decreases. Then, the threshold vehicle speed is set to the value of the vehicle speed when the difference between the jerk set in the second jerk adjustment process and the jerk set in the first jerk adjustment process is equal to or less than a predetermined value.

FIG. 1 is a block diagram showing the main configuration of an electric vehicle equipped with an electric vehicle control system according to an embodiment of the invention. FIG. 2 is a flow chart showing the flow of the electric vehicle control method according to this embodiment. FIG. 3 is a block diagram illustrating an outline of torque command value setting processing. FIG. 4 is a diagram showing an example of an accelerator opening-torque table. FIG. 5 is a block diagram illustrating details of the first torque target value setting process. FIG. 6 is a block diagram illustrating details of the second torque target value setting process according to the first embodiment. FIG. 7 is a diagram for explaining changes over time of each parameter in stop control by the second torque target value setting process of the present embodiment. FIG. 8 is a timing chart for explaining control results using the electric vehicle control method according to this embodiment. FIG. 9 is a block diagram illustrating details of the second torque target value setting process according to the second embodiment. FIG. 10 is a block diagram illustrating details of the second torque target value setting process according to the comparative example. FIG. 11A is a timing chart for explaining the behavior of the electric vehicle when using the second torque target value setting process according to the comparative example (flat road). FIG. 11B is a timing chart for explaining the behavior of the electric vehicle when the second torque target value setting process is used according to the comparative example (uphill road). FIG. 12 is a block diagram illustrating details of the second torque target value setting process according to Modification 1. As shown in FIG. FIG. 13 is a block diagram illustrating details of the second torque target value setting process according to Modification 2. As shown in FIG.

(First embodiment)
A first embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the main configuration of an electric vehicle 100 to which the control method of this embodiment is applied. As illustrated, the electric vehicle 100 includes an electric motor 4 configured by a three-phase AC motor as a vehicle drive source. The electric vehicle 100 is assumed to be any type of vehicle that runs using the driving force of the electric motor 4, such as an electric vehicle (EV), a hybrid vehicle (HEV), and a fuel cell vehicle (FCV).

The electric vehicle 100 is equipped with a battery 1 , a motor controller 2 as a control device, an inverter 3 , and an electric motor 4 , which constitute an electric vehicle control system 10 .

The battery 1 functions as a power source that supplies (discharges) drive power to the electric motor 4, and is connected to the inverter 3 so that it can be charged by receiving regenerative power supplied from the electric motor 4. ing.

The motor controller 2 is composed of a computer including, for example, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input/output interface (I/O interface). The motor controller 2 is programmed so as to be able to execute each process constituting the control method according to this embodiment.

The motor controller 2 obtains the final motor torque command value _Tm ^** based on the detection values of various sensors, and controls the inverter so that the electric motor 4 realizes the actual output torque based on the final motor torque command value _Tm ^** . 3 is operated to control the electric power supplied to the electric motor 4 . Details of the control by the motor controller 2 in this embodiment will be described later.

The inverter 3 includes, for example, two switching elements (for example, power semiconductor elements such as IGBTs and MOS-FETs) for each phase. The supplied DC current is converted into AC current, and a desired current is supplied to the electric motor 4 .

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

The rotation sensor 6 is composed of, for example, a resolver, an encoder, etc., and detects the rotor phase α of the electric motor 4 . The rotation sensor 6 also outputs the detected rotor phase α to the motor controller 2 .

A current sensor 7 detects a motor current (iu, iv, iw) as a three-phase AC current of the electric motor 4 . The current sensor 7 also outputs the detected motor current (iu, iv, iw) to the motor controller 2 . Since the sum (iu+iv+iw) of each component of the three-phase AC motor current (iu, iv, iw) is 0, the current of any two phases is detected by the current sensor 7, and the remaining one phase is The current may be obtained by calculation.

Next, the control method of this embodiment will be described more specifically.

FIG. 2 is a flow chart showing the flow of the control method of this embodiment. It should be noted that the processing of this flowchart is executed by the motor controller 2 at predetermined calculation cycles. That is, the motor controller 2 is programmed to execute the processes from step S100 to step S206 shown in FIG. 2 at predetermined calculation cycles.

In step S100, the motor controller 2 executes an input process to acquire each signal indicating the vehicle state. The acquired signals include the accelerator opening AP [%], the rotor phase α [rad] of the electric motor 4, the motor rotation speed ω _m [rad/s], the motor rotation speed N _m [rpm], and the vehicle speed V [km]. /h], motor current (iu, iv, iw) [A], and DC voltage value Vdc [V] between battery 1 and inverter 3 are included.

Specifically, the accelerator opening AP (%) is obtained as a detection value of an accelerator opening sensor (not shown). Also, the rotor phase α of the electric motor 4 is obtained as a detection value of the rotation sensor 6 .

Furthermore, the motor rotation speed ω _m , which is the mechanical angular speed of the electric motor 4, is obtained based on the rotor phase α. More specifically, the motor controller 2 obtains the electrical angular velocity ω _e of each motor by differentiating the rotor phase α with respect to time, and divides the electrical angular velocity ω _e of the motor by the number of pole pairs of the electric motor 4 to obtain the motor rotation speed ω Obtained as _m [rad/s].

Also, the motor rotation speed N _m is acquired based on the motor rotation speed ω _m . More specifically, the motor controller 2 acquires a value obtained by multiplying the motor rotation speed ω _m by a unit conversion factor (60/2π) as the motor rotation speed N _m [rpm].

Furthermore, the vehicle speed V is calculated based on the motor rotation speed ω _m . A method of calculating the vehicle speed V will be described later. In the following, in order to clearly indicate that the vehicle speed V is a time-dependent function, it will sometimes be referred to as "vehicle speed V(t)".

Also, the motor current (iu, iv, iw) is obtained as a detection value of the current sensor 7 . Furthermore, the DC voltage value Vdc is obtained as a detection value of a voltage sensor (not shown) provided in the DC power supply line between the battery 1 and the inverter 3 .

Next, in step S110, the motor controller 2 executes torque command value setting processing. That is, the motor controller 2 sets the final motor torque command value _{Tm **} based on the accelerator opening AP and the motor rotation speed ^ωm .

In particular, the motor controller 2 of the present embodiment calculates a first torque target value _Tm1 ^* for control during normal running and a second torque target value _Tm2 ^* for control during stoppage. is set as the final motor torque command value T _m ^** .

Here, the first torque target value T _m1 ^* is used during control other than stop control such as normal running of the electric vehicle 100 (running with an output that meets the driver's request) (hereinafter referred to as "non-stop control"). This is the target torque value calculated mainly from the viewpoint of realizing the actual output torque of the electric motor 4 according to the accelerator operation amount by the driver.

On the other hand, the second torque target value T _m2 ^* is set so as to prevent the occupant of the electric vehicle 100 from feeling a sudden stop in the control for stopping the electric vehicle 100 (hereinafter also referred to as “stopping control”). It is a torque target value determined from the viewpoint of adjusting the acceleration a (or deceleration a _d ) of 100. That is, the second torque target value T _m2 ^* is calculated from the viewpoint of smooth deceleration just before the electric vehicle 100 stops.

In the following, in order to clearly indicate that acceleration a and deceleration ad are time-dependent functions, they are sometimes referred to as "acceleration a( _t )" and "deceleration _ad (t)", respectively. do. Moreover, there is a relationship a(t)=-a _d (t) between the acceleration a and the deceleration a _d .

The setting of the final motor torque command value _Tm ^** will be described later in detail.

Next, in step S120, the motor controller 2 executes current command value calculation processing. Specifically, the motor controller 2 refers to a predetermined table based on the motor rotation speed ω _m , the DC voltage value V _dc , and the final motor torque command value T _m ^** set in step S110, and calculates dq A shaft current target value (i _d ^* , i _q ^* ) is calculated.

In step S130, the motor controller 2 executes current control processing. Specifically, the motor controller 2 first calculates dq-axis current values (i _d , i _q ) based on the motor currents (iu, iv, iw) and the rotor phase α.

^Next , the motor controller 2 _calculates the _dq - ^axis _voltage command value ₍ v _d , v _q ). A non-interference voltage required to cancel the interference voltage between the dq orthogonal coordinate axes may be added to the calculated dq-axis voltage command values (v _d , v _q ).

Furthermore, the motor controller 2 uses the rotor phase α to convert the dq-axis voltage command values (v _d , v _q ) from the dq coordinate system to the uvw coordinate system, so that the three-phase AC voltage command values (vu, vv , vw).

Then, the motor controller 2 generates PWM signals (tu, tv, tw) [%] based on the calculated three-phase AC voltage command values (vu, vv, vw) and the DC voltage value Vdc, and converts them to the inverter 3 output to Further, an inverter controller (not shown) opens and closes the switching elements of the inverter 3 based on the PWM signals (tu, tv, tw). As a result, the electric power supplied to the electric motor 4 is adjusted so that the electric motor 4 is driven by the actual output torque based on the final motor torque command value _Tm ^** .

The torque command value setting process in step S110 will be described in more detail below.

FIG. 3 is a block diagram illustrating the functions of the motor controller 2 that performs torque command value setting processing.

As shown in the figure, the motor controller 2 includes a first torque target value setting section B200, a second torque target value setting section B210, and a max select section B220 as a configuration for realizing the function of executing the torque command value setting process. , and a previous value acquisition unit B230.

A first torque target value setting unit B200 calculates a first torque target value _Tm1 ^* based on the accelerator opening AP and the motor rotation speed _ωm .

FIG. 4 is a block diagram illustrating more detailed functions of the first torque target value setting section B200.

As illustrated, the first torque target value setting unit B200 has a torque table target value setting unit B201, a gradient torque estimation unit B202, and an addition unit B203.

A torque table target value setting unit B201 calculates a torque table target value T _m1 by referring to a predetermined accelerator opening-torque table based on the accelerator opening AP and the motor rotation speed ω _m .

FIG. 5 shows an example of an accelerator opening-torque table. As shown in FIG. 5, the torque table target value _Tm1 is set to a value that increases as the accelerator opening AP increases, according to the magnitude of the motor rotation speed _ωm . In particular, when the accelerator opening AP is a predetermined value or more (2/8 or more in FIG. 5), the torque table target value _Tm1 is set to a positive value. On the other hand, when the accelerator opening AP is less than the predetermined value (1/8 or less in FIG. 5), the torque table target value T _m1 is set to a negative value so as to decelerate the electric vehicle 100 . Thereby, regenerative braking of electric vehicle 100 is realized based on the accelerator operation by the driver.

This accelerator opening-torque table is stored in advance in a storage area (not shown) of the motor controller 2. FIG.

Returning to FIG. 4, the torque table target value setting unit B201 outputs the calculated torque table target value T _m1 to the addition unit B203.

Next, the gradient torque estimator _B202 calculates the gradient torque estimated value _{Tds based on the motor rotation speed ωm and the final torque command value previous value Tm_pr **} ^. The final torque command value previous value _{Tm_pr} ^** is the value of the final motor torque command value _Tm ^** calculated in the previous control cycle.

Specifically, the gradient torque estimator B202 first performs a filtering process on the motor rotation speed ω _m using a filter based on an appropriate vehicle model according to the electric vehicle 100 to calculate a first motor torque estimation value. On the other hand, the gradient torque estimator B202 applies a low-pass filter to the final torque command value previous value _{Tm_pr} ^** to calculate a second motor torque estimation value. Then, the gradient torque estimator B202 subtracts the first motor torque estimated value from the second motor torque estimated value, and performs appropriate filtering on the value obtained by the subtraction to obtain the gradient torque estimated value T ask for _ds .

That is, the gradient torque estimated value T _ds is obtained from the final torque command value previous value T _{m_pr} ^** corresponding to the actual output torque of the electric motor 4 and the motor rotation speed ω _m corresponding to the actual rotation speed of the electric motor 4 . It is a parameter calculated as a difference between the theoretical output torque determined according to the vehicle model of the vehicle 100 . In other words, the gradient torque estimated value T _ds of the present embodiment is a theoretical output torque determined from the actual output torque of the electric vehicle 100 and an ideal vehicle model according to the magnitude of the gradient of the road on which the electric vehicle 100 is running. is a parameter that represents the difference between

The gradient torque estimator B202 outputs the calculated gradient torque estimated value _Tds to the adder B203.

The adder _B203 adds the gradient torque estimated value _Tds to the torque table target value Tm1 to obtain the first torque target value _Tm1 ^* . Then, the addition section B203 outputs the calculated first torque target value T _m1 ^* to the max select section B220.

Returning to FIG. 3, the second torque target value setting unit B210 calculates the second torque target value _Tm2 ^* used in stop control based on the accelerator opening AP and the motor rotation speed _ωm . Details of calculation of the second torque target value T _m2 ^* will be described later.

The second torque target value setting section B210 outputs the calculated second torque target value T _m2 ^* to the max select section B220.

The max select unit B220 selects the larger one of the first torque target value T _m1 ^* from the first torque target value setting unit B200 and the second torque target value T _m2 ^* from the second torque target value setting unit B210 as the final value. Set as motor torque command value T _m ^** . If the first torque target value _Tm1 ^* and the second torque target value _Tm2 ^* are the same value, the value is set as the final motor torque command value _Tm ^** .

That is, in the present embodiment, when the first torque target value T _m1 ^* > the second torque target value T _m2 ^* , the max select section B220 changes the first torque target value T _m1 ^* to the final motor torque command value T _m ^*. The non-stop control set as ^* is executed. Also, when the first torque target value T _m1 ^* <the second torque target value T _m2 ^* , the second torque target value T _m2 ^* is set as the final motor torque command value T _m ^** . be done.

Then, based on the set final motor torque command value T _m ^** , the max select section B220 outputs to the process of step S120 in FIG. 2 and to the previous value acquisition section B230.

The previous value acquisition unit B230 acquires the final motor torque command value _Tm ^** from the max select unit B220 as the final torque command value previous value _{Tm_pr} ^** . Then, the previous value acquisition unit B230 returns the acquired final torque command value previous value _{Tm_pr} ^** to the first torque target value setting unit B200 and the second torque target value setting unit B210.

According to such a configuration of the present embodiment, the electric vehicle 100 basically satisfies the first torque target value T _m1 ^* > the second torque target value T _m2 ^* during non-stop control such as normal running. As a result, the first torque target value _Tm1 ^* based on the driver's request is set as the final motor torque command value _Tm ^** .

During this non-stop control, when the driver reduces the accelerator opening AP to a certain extent in order to stop the electric vehicle 100, the first torque target value _Tm1 ^* becomes negative according to the accelerator opening-torque table of FIG. is set to the value of Thus, the vehicle speed V also decreases continuously by setting the negative first torque target value T _m1 ^* . At the timing when the vehicle speed V reaches a predetermined switching vehicle speed _Vsw (hereinafter also simply referred to as "torque switching timing"), the first torque target value _Tm1 ^* and the second torque target value _Tm2 ^* approximately equal.

Therefore, when the vehicle speed V reaches the switching vehicle speed _Vsw , the final motor torque command value _Tm ^** switches from the first torque target value _Tm1 ^* to the second torque target value _Tm2 ^* . That is, the motor controller 2 executes non-stop control when the vehicle speed V≧switching vehicle speed V _sw , and executes stop control when the vehicle speed V>switching vehicle speed V _sw .

Below, setting of the second torque target value T _m2 ^* , which is set as the final motor torque command value T _m ^** in such stop control, will be described.

[Comparative example]
For reference, first, a method of setting the second torque target value T _m2 ^* in a comparative example based on the configuration described with reference to FIGS. 1 to 5 will be described.

FIG. 10 is a block diagram illustrating the details of the functions of the second torque target value setting section B210 in the comparative example.

As illustrated, the second torque target value setting section B210 of the comparative example has a gain multiplication section B311, a first-order lag processing section B312, a gradient torque setting section B313, and an addition section B314.

A gain multiplier B311 multiplies the motor rotation speed ω _m [rad/s] by a fixed gain K _vf to obtain a parameter K _vf ·ω _m [N·m]. Here, the fixed gain K _vf is a negative fixed value determined from the viewpoint of smoothly decelerating the electric vehicle 100 . The fixed gain K _vf is determined in advance by experiments or the like.

A first-order lag processing unit B312 performs first-order lag processing on the parameter K _vf ·ω _m from the gain multiplier B311. A basic torque target value T _m2 at stop is calculated.

Specifically, the first-order lag processing unit _B312 obtains the stop basic torque target value _Tm2 by applying first-order lag processing to the parameter _Kvf ·ωm using a filter represented by the following equation (1).

なお、式（１）中のτは時定数である。

Note that τ in Equation (1) is a time constant.

Then, the first-order lag processing section B312 outputs the obtained stop basic torque target value T _m2 to the addition section B314.

On the other hand, the gradient torque setting unit B313 calculates the gradient torque estimated value T _ds based on the final torque command value previous value T _{m_pr} ^** from the previous value acquisition unit B230 by the same calculation method as the gradient torque estimating unit B202 described above. calculate.

Specifically, the gradient torque setting section B313 calculates the gradient torque estimated value _Td in the same manner as the gradient torque estimating section B202 described above. Then, the gradient torque setting unit B313 determines the gradient of the road surface based on the gradient torque estimated value _Td , and multiplies the determined gradient by a predetermined gain to obtain the gradient torque estimated value _Tds . The gradient torque setting unit B313 then outputs the calculated gradient torque estimated value Tds to the addition unit _B314 .

The addition unit _{B314 adds} the estimated gradient torque value Tds from the gradient torque setting unit B313 to the stop basic torque target value Tm2 from the first-order lag processing unit _B312 , thereby obtaining the second torque target value Tm2 ^*. Ask for Then, this second torque target value T _m2 ^* is output to the max select section B220 described with reference to FIG.

In the configuration of the comparative example described above, by using the fixed gain _Kvf that is predetermined according to the characteristics of the electric vehicle 100, the change in the deceleration _ad of the electric vehicle 100 during the stop control is suppressed. Thus, smooth stopping of the electric vehicle 100 is realized. However, the inventors of the present invention focused on the fact that, in the configuration of this comparative example, there are scenes in which it cannot be said that the sudden stop feeling given to the occupant of the electric vehicle 100 can be sufficiently suppressed. The reason will be explained in more detail.

FIG. 11A is a timing chart showing control results of electric vehicle 100 based on the configuration of the comparative example. In particular, FIG. 11A shows control results in a scene in which electric vehicle 100 is traveling on an uphill road.

Note that FIG. 11A(a) shows changes over time in the vehicle speed V(t). Also, FIG. 11A(b) shows the change over time of the final motor torque command value T _m ^** . Further, FIG. 11A(c) shows changes over time in G acting on the occupant of the electric vehicle 100. FIG. Also, FIG. 11(d) shows the change over time of the jerk j(t) [m/s ³ ].

In this specification, the jerk j(t) of the electric vehicle 100 is a value defined as the first derivative of the acceleration a(t) with respect to time, and is called a "jerk" or a "jerk." It is also called a physical quantity.

In the control result during flat road running indicated by the dashed line in FIG. 11A , from time t0 to time t3, which is the torque switching timing, the first torque target value T based on the accelerator operation of the driver who wishes to stop the electric vehicle 100 is _m1 ^* (<0) is set as the final motor torque command value _Tm ^** . Thus, the vehicle speed V decreases based on the negative final motor torque command value T _m ^** being set (see FIG. 11A(a)). At time t3, the vehicle speed V reaches the switching vehicle speed _Vsw , the first torque target value _Tm1 ^* becomes smaller than the second torque target value _Tm2 ^* , and the second torque target value _Tm2 ^* reaches the final value. It is set as the motor torque command value T _m ^** .

Here, as described with reference to FIG. 10, the second torque target value T _m2 ^* is basically the value obtained by multiplying the motor rotation speed ω _m by the fixed gain K _vf with the first-order lag of the time constant τ. It is obtained by processing. Therefore, after the time t3, the final motor torque command value _Tm ^** using the second torque target value _Tm2 ^* draws a first-order lag curve profile corresponding to the time constant τ, while the electric vehicle 100 converges to the target value (=0) for stopping (see FIG. 11A(b)).

However, at the torque switching timing of time t3, the final motor torque command value _Tm ^** abruptly changes due to the switching from the first torque target value _Tm1 ^* to the second torque target value _Tm2 ^* .

For this reason, the change in G at the torque switching timing at time t3 is not smooth (see FIG. 11A(c)). occurs (see FIG. 11A(d)). The inventors have found that the peak P of the jerk j(t) may give the occupant of the electric vehicle 100 a sudden stop feeling.

It should be noted that the occurrence of such a peak P of the jerk j(t) becomes more conspicuous in a control scene during running uphill.

Specifically, in the control result when traveling on an uphill road shown in FIG. 11B, the electric vehicle 100 is traveling on an uphill road, so the vehicle speed V decreases more quickly than on a flat road (see FIG. 11B(a)). . That is, the motor rotation speed ω _m decreases faster than on a flat road, and the torque table target value T _m1 based on the table in FIG. (see map). As a result, the first torque target value _Tm1 ^* based on this torque table target value _Tm1 also decreases more quickly.

Therefore, the torque switching timing at which the first torque target value T _m1 ^* becomes equal to or less than the second torque target value T _m2 ^* is time t1 earlier than when traveling on a flat road. Even when traveling on an uphill road, after time t1 at which the torque is switched, the final motor torque command value T _m ^** draws a first-order lag profile corresponding to the time constant τ, and stops the electric vehicle 100. It converges to the target value for

However, when traveling on an uphill road, the second torque target value T _m2 ^* is different from the basic torque target value T _m2 at stop based on the motor rotation speed ω _m , the gradient torque estimated value T corresponding to the gradient of the uphill road. It is calculated by adding _ds (>0) (see addition unit B314 in FIG. 10). For this reason, the torque target value for stopping the electric vehicle 100 is set to be larger by the gradient torque estimated value T _ds compared to that during flat road running (that is, 0) (see FIG. 11B(b)).

On the other hand, based on the control logic of FIG. 10, even in the control scene during running uphill, the second torque target value T _m2 ^* (final motor torque command value T _m ^** ) is the first-order lag processing section B312. is calculated by one-delay processing based on the same time constant τ. That is, even when traveling on an uphill road, control is executed to converge the final motor torque command value T _m ^** to the target value in substantially the same time as when traveling on a flat road. The change in value T _m ^** becomes steeper (see FIG. 11B(b)).

As a result, the peak P of the jerk j(t) becomes larger (see FIG. 11B(d)), causing a more rapid change in G at time t1, which is the torque switching timing. The sudden stop feeling to be given becomes stronger. The present inventors focused on such problems and made the improvements described below.

[This embodiment]
FIG. 6 is a block diagram illustrating the details of the functions of the second torque target value setting section B210 in this embodiment. In addition, the same code|symbol is attached|subjected to the element similar to a comparative example as needed, and the description is abbreviate|omitted.

As illustrated, the second torque target value setting unit B210 of this embodiment includes a vehicle speed conversion unit B211, a first-order lag processing unit B212, a threshold vehicle speed setting unit B213, a magnitude determination unit B214, and a gain calculation unit B215. , a fixed gain setting unit B216, a switching unit B217, a multiplication unit B218, a gradient torque setting unit B219, and an addition unit B2111.

A vehicle speed conversion unit B211 multiplies the motor rotation speed ω _m [rad/s] by a predetermined conversion gain K _c to calculate a vehicle speed conversion value K _c ·ω _m [km/h]. Note that the conversion gain K _c is a value appropriately determined from the viewpoint of correcting the motor rotation speed ω m to a value close to the actual speed of the electric vehicle 100 while converting the unit of the motor rotation speed ω _m into the unit of speed. Specifically, the conversion gain _Kc can be determined by the tire load radius r, the gear ratio N of the final gear in the speed reducer 5, and the unit conversion coefficient 3600/1000. More specifically, the conversion gain K _c is set to (r/N)×(3600/1000) so that the wheel rotation speed w of the electric vehicle 100 is regarded as the vehicle speed V. Then, the vehicle speed conversion unit _B211 outputs the calculated vehicle speed conversion value _Kc ·ωm to the first-order delay processing unit B212.

The first-order lag processing unit B212 obtains the vehicle speed V based on the vehicle speed conversion value _Kc ·ωm from the vehicle speed conversion unit _B211 . Specifically, the first-order lag processing unit B212 obtains the vehicle speed V( _t ) by applying first-order lag processing based on the filter represented by the above equation (1) to the vehicle speed conversion value _Kc ·ωm. As a result, the vehicle speed V(t) is determined as a function of time corresponding to the first-order lag curve of the time constant τ. Specifically, the vehicle speed V(t) is represented by the following formula (2).

ただし、Ｖ₀はＶ（ｔ）の初期条件に応じて定まる定数である。

However, V ₀ is a constant determined according to the initial conditions of V(t).

Then, the first-order lag processing section B212 outputs the obtained vehicle speed V(t) to the magnitude determination section B214 and the gain calculation section B215.

On the other hand, the threshold vehicle speed setting unit B213 outputs the threshold vehicle speed V _th previously recorded in the memory or the like in the motor controller 2 to the magnitude determination unit B214. The significance of the threshold vehicle speed _Vth will be described later.

The magnitude determination unit B214 determines magnitude between the vehicle speed V(t) from the first-order lag processing unit B212 and the threshold vehicle speed V _th from the threshold vehicle speed setting unit B213. The magnitude determination section B214 outputs the binary signal Bs corresponding to the determination result to the switching section B217. Specifically, the magnitude determination unit B214 sets "1" as the binary signal Bs when it determines that the vehicle speed V(t) is greater than the threshold vehicle speed _Vth , and otherwise sets "0" as the binary signal Bs. ” to the switching unit B217.

Next, the gain calculator B215 calculates a variable gain _Kvv based on the vehicle speed V(t) from the first-order lag processor B212.

Specifically, in this embodiment, the gain calculator B215 sets the variable gain K _vv as a function of time t represented by the following equation (3).

Note that M _V in the formula means the equivalent mass of the electric vehicle 100 . The equivalent mass M _V of the electric vehicle 100 is a physical quantity determined based on the vehicle body mass M, the gear ratio N of the final gear, the drive wheel inertia J _w , and the motor inertia J _m . Also, "r" in the formula is the load radius of the tire.

In particular, the gain calculator B215 in this embodiment determines the variable gain _Kvv of the above equation (3) so that the jerk j(t) takes a fixed jerk value _kj that does not depend on the time t.

An example of an algorithm for calculating the variable gain K _vv will be specifically described below.

First, the gain calculator B215 differentiates the vehicle speed V(t) represented by the above equation (2) to obtain the acceleration a(t) represented by the following equation (4).

Further, the gain calculator B215 differentiates the acceleration a(t) in the above equation (4) to find the jerk j(t) expressed in the following equation (5).

Next, the gain calculation unit B215 calculates the acceleration a(t) and the vehicle speed V(t) under the condition that the jerk j(t) takes the jerk fixed value k _j in the formulas (3) to (5). Ask for

Specifically, the gain calculation unit B215 calculates the acceleration a(t _k ) at time t _k when the jerk j(t) in Equation (5) takes the jerk fixed value k _j (hereinafter referred to as the “acceleration reference value a _k ”) and vehicle speed V(t _k ) (hereinafter also referred to as “vehicle speed reference value V _k ”).

Referring to the above formulas (2), (4), and (5), the jerk fixed value k _j , the acceleration reference value a _k , and the vehicle speed reference value V _k are respectively obtained from the following formulas (6) to (8).

The time t _k is eliminated based on the above formulas (6) to (8), and the vehicle speed reference value V _k and the acceleration reference value a _k are determined by the following formulas (9) and (10).

_Next , the _acceleration a( _t ) and the vehicle speed V(t). Note that the functional acceleration a(t) and vehicle speed V(t) specified in this manner are distinguished from the acceleration a(t) in equation (4) and the vehicle speed V(t) in equation (2). Therefore, they are referred to as "acceleration a'(t)" and "vehicle speed V'(t)", respectively.

Further, in the following calculations, instead of the acceleration a'(t), deceleration ad'(t) having positive and negative polarities opposite to the acceleration a'( _t ) is used for convenience. Accordingly, the relationship among the fixed jerk value k _j , deceleration a _d '(t), and vehicle speed V'(t) is represented by the following equations (11) to (13).

Eliminating the time t in the above equations (11) to (13) and obtaining the relationship between the deceleration ad'( _t ) and the vehicle speed V'(t) yields the following equations (14) and (15): is obtained.

The variable gain K _vv can be determined by appropriately applying the above equations (12) to (15) to the equation (3). In particular, the deceleration _ad '(t) of equation (15) is inverted in sign and applied to the acceleration a(t) portion of equation (3), and the vehicle speed V'(t) is the vehicle speed of equation (3). By applying it to V(t), the variable gain _Kvv will be expressed as a function of the vehicle speed V'(t). Specifically, the variable gain K _vv is represented by the following equation (16).

Therefore, by applying the vehicle speed V(t) determined by the first-order lag processing unit B212 to the vehicle speed V' portion of the above equation (16), the variable gain _Kvv that changes according to the magnitude of the vehicle speed V(t) is Obtainable.

Then, the gain calculation section B215 outputs the obtained variable gain K _vv to the switching section B217.

On the other hand, the fixed gain setting section B216 outputs the fixed gain K _vf prerecorded in the memory or the like in the motor controller 2 to the switching section B217. This fixed gain K _vf is set to a constant value that does not depend on changes in the vehicle speed V(t), like the fixed gain K _vf described in the comparative example.

Next, the switching unit B217 transfers the variable gain K _vv from the gain calculation unit B215 or the fixed gain K _vf from the fixed gain setting unit B216 to the multiplication unit B218 based on the binary signal Bs from the magnitude determination unit B214. Output.

Specifically, when the switching unit B217 receives the binary signal Bs "1" from the magnitude determination unit B214 (that is, when vehicle speed V(t)>threshold vehicle speed _Vth ), the switching unit B217 multiplies the variable gain K _vv Output to section B218. On the other hand, when the switching unit B217 receives the binary signal Bs "0" from the magnitude determination unit B214 (when the vehicle speed V(t)≤the threshold vehicle speed _Vth ), the switching unit B217 outputs the fixed gain K _vf to the multiplication unit B218. do.

That is, in the present embodiment, a gain for calculating the second torque target value T _m2 ^* (hereinafter referred to as “jerk adjustment processing gain K _v ”) is determined according to the magnitude relationship between the vehicle speed V(t) and the threshold vehicle speed V _th . ), a variable gain K _vv or a fixed gain K _vf is set.

The multiplication unit B218 multiplies the jerk adjustment processing gain K _v from the switching unit B217 by the motor rotation speed ω _m to obtain the stop basic torque target value T _m2 . Then, the multiplication unit B218 outputs the calculated stop basic torque target value T _m2 to the addition unit B2111.

On the other hand, the slope torque setting unit _B219 calculates the slope torque estimated value Tds based on the final torque command value previous value _{Tm_pr} ^** from the previous value obtaining unit B230 in FIG. The calculation method of this gradient torque estimated value _Tds is the same as the calculation method in the gradient torque setting section B313 described above.

The adder _B2111 adds the slope torque estimated value Tds from the slope torque setting unit _B219 to the stopping basic torque target value Tm2 from the multiplier _B218 to obtain the second torque target value Tm2 ^* . Then, the adding section B2111 outputs the obtained second torque target value T _m2 ^* to the max select section B220 in FIG.

FIG. 7 is a diagram illustrating changes in each parameter of electric vehicle 100 due to the processing of second torque target value setting unit B210.

In the present embodiment, according to the processing of the second torque target value setting unit B210, the vehicle speed V(t) reaches the threshold vehicle speed V _th after the transition from the non-stop control to the stop control (stop control 2), the second torque target value _Tm2 ^* is set based on the stop basic torque target value _Tm2 obtained by multiplying the motor rotation speed _ωm by the variable gain _Kvv . On the other hand, after the vehicle speed V(t) reaches the threshold vehicle speed V _th (the second half of the stop control), the motor rotation speed ω _m is multiplied by the fixed gain K _vf to obtain the basic torque target value T _m2 during stop. 2 A torque target value T _m2 ^* is set.

Therefore, as shown in FIG. 7, in the first half of the stop control, the variable gain _Kvv is set and the jerk j(t) is limited to the fixed jerk value _kj . Therefore, the electric vehicle 100 decelerates based on the acceleration a (deceleration a _d ) in which the jerk j(t) is maintained at the fixed jerk value k _j . On the other hand, in the stopping control, a fixed gain _Kvf is set as the jerk adjustment processing gain _Kv in the second half after the vehicle speed V(t) reaches the threshold vehicle speed _Vth . Therefore, as in the case of the comparative example, the electric vehicle 100 decelerates while adopting a first-order lag profile in which the jerk j and the acceleration a (deceleration a _d ) gradually approach 0 and decrease as the vehicle speed V decreases. .

In the present embodiment, the threshold vehicle speed V _th for defining the timing of switching the jerk adjustment processing gain K _v from the variable gain K _vv to the fixed gain K _vf (hereinafter also referred to as "gain switching timing") is The jerk j(t) determined based on the fixed gain K _vf set in the second half of the stop control is a predetermined value with respect to the fixed jerk value k _j based on the variable gain K _vv set in the first half of the stop control. The value of the vehicle speed V is set within the range. In particular, in the present embodiment, the threshold vehicle speed V _th is a vehicle speed reference value that is the vehicle speed V at time t _k when the jerk j in the latter half of the stop control substantially coincides with the jerk fixed value k _j in the first half of the stop control. is set to _Vk .

FIG. 8 is a timing chart for explaining control results using the control method according to this embodiment. In particular, FIG. 8 shows the control results in a scene in which the electric vehicle 100 is traveling on an uphill road. For reference, the dashed line indicates the control result in a scene in which the electric vehicle 100 is traveling on an uphill road in the comparative example.

8(a), 8(b), 8(c), and 8(d) respectively show vehicle speed V(t), final motor torque command value T _m ^** , G, and acceleration. It shows the change over time of the degree j(t). Further, time t0 represents the torque switching timing (that is, the start timing of the stop control) in the control result of the present embodiment, and time t2 represents the gain switching timing (that is, the timing of shifting from the first half of the stop control to the latter half). show.

As shown, according to the control method of the present embodiment, from time t0 to time t2, which is the first half of the stop control, according to the control logic described with reference to FIG. 6, the second torque target value T _m2 ^* ( By setting the final motor torque command value T _m ^** based on the variable gain K _vv , the final motor torque command value T _m ^** increases substantially linearly with respect to time t (Fig. 8 (b )reference). Therefore, the jerk j(t) from time t0 to time t2 is limited to the fixed jerk value _kj or less (see FIG. 8(d)). In particular, in the first half of the stop control, the jerk j(t) is maintained substantially at the fixed jerk value k _j . Therefore, a rapid change in G from time t0 to time t2 is suppressed (see FIG. 8(c)). That is, by preventing the occurrence of excessive jerk j at the torque switching timing as shown by the control result of the comparative example indicated by the dashed line (see the dashed line in FIG. 8(d)), the sudden stop feeling given to the occupant of the electric vehicle 100 is reduced. can be suppressed.

Furthermore, according to the control method of the present embodiment, the vehicle speed V(t) reaches the threshold vehicle speed _Vth at time t2, which is the gain switching timing (see FIG. 8A). Therefore, after time t2, which is the latter half of the stop control, the second torque target value _Tm2 ^* is determined based on the fixed gain _Kvf according to the control logic described with reference to FIG. As a result, as in the case of the comparative example, the jerk j and the deceleration ad take a first-order lag profile in which the _jerk j and the deceleration ad decrease asymptotically to 0 as the vehicle speed V decreases. That is, in the second half of the stop time control, as in the case of the comparative example, the vehicle can be stopped smoothly without giving the occupant a feeling of sudden stop.

In particular, in the present embodiment, the threshold vehicle speed V _th is the vehicle speed at time t _k (=time t2) at which the jerk j in the second half of the stop control substantially coincides with the fixed jerk k _j in the first half of the stop control. It is set to the vehicle speed reference value V _k which is V. Therefore, the occurrence of a step in the jerk j at the gain switching timing is more preferably suppressed. That is, it is possible to more effectively suppress the sudden stop feeling given to the occupant of the electric vehicle 100 at the gain switching timing.

The effects of the configuration of the present embodiment described above will be described below.

In the present embodiment, a control method for the electric vehicle 100 is provided, which executes stop control (see FIG. 6) for decelerating and stopping the electric vehicle 100 by regenerative braking force of the electric motor 4 .

Stopping control (control when second torque target value T _m2 ^* >first torque target value T _m1 ^* ) is performed when vehicle speed V exceeds threshold vehicle speed V _th value signal Bs=1 is output), the first jerk adjustment process (gain calculator _B215 , switching section B217 and multiplication section B218), and when the vehicle speed V is equal to or lower than the threshold vehicle speed _Vth (when the binary signal Bs=0 is output from the magnitude determination section B214 in FIG. 6), the deceleration of the electric vehicle 100 A _d (t) and a jerk j(t) are jogged so as to take a profile (after time t2 in FIGS. 8(c) and 8(d)) in which they asymptotically approach 0 and decrease as the vehicle speed V decreases. a second jerk adjustment process (fixed gain setting unit B216, switching unit B217, and multiplication unit B218) for adjusting the degree j.

The threshold vehicle speed V _th is the predetermined difference between the jerk fixed value k _j as the jerk j set in the second jerk adjustment process and the jerk j set in the first jerk adjustment process. It is set to the value of the vehicle speed V (vehicle speed reference value V _k ) when:

As a result, in the first half of the stopping control when the vehicle speed V exceeds the threshold vehicle speed _Vth , the jerk j is limited to the fixed jerk value _kj or less, so that the peak of the jerk j can be suppressed. can. Therefore, it is possible to suppress the sudden stop feeling given to the occupant of the electric vehicle 100 due to an excessively high value of the jerk j.

Further, in the second half of the stop time control when the vehicle speed V reaches the threshold vehicle speed _Vth , the deceleration ad and the _jerk j of the electric vehicle 100 are reduced to asymptotically 0 as the vehicle speed V decreases. adjust j. Therefore, in the second half of the stopping control, the process of reducing the jerk j is executed continuously from the first half of the stopping control in which the jerk j was limited. Therefore, the magnitude of the jerk j is suppressed even in the latter half of the stop control, so that the electrically powered vehicle 100 can be smoothly stopped.

Further, in the present embodiment, the threshold vehicle speed V _th is set when the difference between the jerk fixed value k _j in the second jerk adjustment process and the jerk j in the first jerk adjustment process is equal to or less than a predetermined value, particularly 0. is set to the value of the vehicle speed V of That is, the _{threshold vehicle speed} V _th is the value of the vehicle speed V ( vehicle speed reference value V _k ). It should be noted that such a threshold vehicle speed _Vth can be determined in advance through experiments or the like.

As a result, it is possible to suppress a step in the jerk j at the time of switching between the first jerk adjustment process and the second jerk adjustment process (gain switching timing). In other words, it is possible to suppress the change in the deceleration _ad when the control is switched. Therefore, the switching of the control can be executed without giving the occupant of the electric vehicle 100 a sudden stop feeling.

Therefore, according to the present embodiment, the vehicle can be stopped smoothly by suppressing the occupant's feeling of sudden stop during the process from the start to the end of the stop control (stop of the electric vehicle 100).

In particular, the control method of the present embodiment suitably suppresses the peak of the jerk j even when traveling on an uphill road where the peak of the jerk j becomes larger in the above-described reference example, thereby giving the occupant of the electric vehicle 100 a sudden stop feeling. You can restrain yourself from giving. That is, the control method of the present embodiment exhibits a more remarkable effect in a scene where the electric vehicle 100 is traveling on an uphill road.

In particular, in the control method of the electric vehicle 100 according to the present embodiment, the stopping control multiplies the vehicle speed conversion value _Kc · _ωm as a speed parameter proportional to the vehicle speed by the jerk adjustment processing gain _Kv as a predetermined gain. This includes a motor torque command value setting step (step S110 in FIG. 2 and FIG. 6) for setting the second torque target value _Tm2 ^* as the motor torque command value corresponding to the regenerative braking force.

The first jerk adjustment process is executed by setting the jerk adjustment process gain K _v to a variable gain K _vv as a variable value whose absolute value decreases as the vehicle speed V increases (gain calculation section B215 and switching unit B217). On the other hand, the second jerk adjustment process is executed by setting the jerk adjustment process gain K _v to a fixed gain K _vf that is a constant fixed value with respect to changes in the vehicle speed V (fixed gain setting unit B216 and a first-order lag processing unit B212).

As a result, while the _jerk j is limited to the fixed jerk value _kj or less in the first half of the stop control, the deceleration ad and the jerk j asymptotically decrease to 0 as the vehicle speed V decreases in the second half. The behavior of the electric vehicle 100 can be realized with simple control logic.

Furthermore, the present embodiment provides the electric vehicle control system 10 including the motor controller 2 as a stop time control device that decelerates and stops the electric vehicle 100 by regenerative braking force of the electric motor 4 .

Then, when the vehicle speed V exceeds the threshold vehicle speed _Vth (when the binary signal Bs=1 is output from the magnitude determination unit B214 in FIG. 6), the motor controller 2 sets the jerk j of the electric vehicle 100 to a predetermined value. It has a first jerk adjustment unit (gain calculation unit B215, switching unit B217, and multiplication unit B218) that adjusts the jerk fixed value k _j or less, which is the upper limit value.

Further, the motor controller 2 controls the _{deceleration ad (} t) and the jerk j(t) is adjusted so that the profile (after time t2 in FIGS. 8(c) and 8(d)) asymptotically approaches 0 and decreases as the vehicle speed V decreases. It has a second jerk adjustment unit (fixed gain setting unit B216, switching unit B217, and multiplication unit B218) for adjustment.

The threshold vehicle speed V _th is the value of the vehicle speed V (vehicle speed reference value V _k ).

As a result, a system configuration suitable for executing the control method of the electric vehicle 100 is realized.

(Second embodiment)
A control method for the electric vehicle 100 according to the second embodiment of the above embodiment will be described below. Note that the control method described below is the same as that of the above embodiment except for some processing in the second torque target value setting section B210. Therefore, in the control method of this embodiment, description of the same parts as in the above embodiment will be omitted.

FIG. 9 is a block diagram illustrating the functions of the second torque target value setting section B210 according to this embodiment.

As illustrated, the second torque target value setting section B210 in this embodiment includes a gain setting section B2112 instead of the magnitude determination section B214, gain calculation section B215, and switching section B217 in the first embodiment. .

The gain setting section B2112 is configured in advance in a storage area (not shown) within the motor controller 2 . Specifically, the gain setting unit _B2112 has a vehicle speed-gain table that defines the correspondence between the value of the vehicle speed V(t) and the jerk adjustment processing gain Kv that is determined accordingly.

Specifically, the vehicle speed-gain table is configured as shown in Table 1 below.

In particular, the vehicle speed-gain table stores the vehicle speed V below the threshold vehicle speed V _th and the fixed gain K _vf in association with each other, and also stores the vehicle speed V above the threshold vehicle speed V _th and the variable gain calculated in advance accordingly. K _vv is associated and stored.

Then, the gain setting unit B2112 refers to the vehicle speed-gain table based on the vehicle speed V from the first-order delay processing unit B212, sets the variable gain K _vv or the fixed gain K _vf according to the vehicle speed V, and sets the multiplier B218.

That is, in this embodiment, by using the vehicle speed-gain table defined in Table 1 in advance, the same control method can be executed without executing the calculation by the gain calculation section B215 in the above embodiment in real time. can.

The effects of the configuration of the present embodiment described above will be described.

In this embodiment, the jerk adjustment processing gain K _v is referred to a vehicle speed-gain table in which the vehicle speed V(t) and the jerk adjustment processing gain K _v determined according to the vehicle speed V(t) are associated with each other. Set by

As a result, the same stop control can be realized while reducing the calculation load of the motor controller 2 without calculating the variable gain K _vv described in the first embodiment in real time.

In particular, in the calculation of the variable gain K _vv described in the first embodiment, when the jerk j(t) represented by the first-order lag curve takes a fixed jerk value k _j as in the above equation (5), Since it is necessary to calculate the logarithm of the equation (5) in calculating the time t _k of , there is concern that the calculation load on the motor controller 2 will be relatively high. On the other hand, with the configuration of the present embodiment, there is no need to perform such logarithmic calculation in real time, so the effect of reducing the calculation load is remarkable.

Although the embodiments of the present invention have been described above, each of the above embodiments merely shows a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configurations of the above embodiments. is not.

For example, in the above embodiment, the second torque target value T _m2 ^* is calculated based on the vehicle speed conversion value K _c ·ω _m as the speed parameter proportional to the vehicle speed V. However, as long as it is proportional to the vehicle speed V, other speed parameters may be used while appropriately adjusting the gain. For example, in the block diagram of FIG. 6 or FIG. 9, after correcting the conversion gain K _c to an appropriate gain K _c ', it is possible to input the motor rotation speed N _m instead of the motor rotation speed ω _m . That is, the speed parameter proportional to the vehicle speed V _may be changed to _Kc'Nm .

Further, in the above-described embodiment, as a configuration for realizing a profile in which the deceleration ad( _t ) and the jerk j(t) of the electric vehicle 100 asymptotically decrease to 0 as the vehicle speed V decreases, An example in which two first-order lag processing units B212 are provided has been described. However, when it is necessary to ensure a gain margin more reliably due to the specifications of the electric vehicle 100, as shown in FIG. 12 (Modification 1) or FIG. The electric vehicle control system 10 provided with B212 and B212' may be employed. Also in this case, the function of the second torque target value setting section B210 described in the above embodiment can be realized by a similar method.

Furthermore, in the above embodiment, an example in which the electric vehicle control method and the electric vehicle control system 10 of the present invention are mainly applied to the electric vehicle 100 having one electric motor 4 has been described. However, the control method and control system of the above embodiment can also be applied to an electric vehicle 100 including a plurality of electric motors 4, such as a 4WD vehicle, with some modifications. For example, in an electric vehicle 100 having a plurality of electric motors 4, by distributing the final motor torque command value _Tm ^** obtained by the method of the above embodiment to each electric motor 4 with an appropriate distribution gain, such a Also in the electric vehicle 100, it is possible to obtain the same effects as those of the above-described embodiment.

Furthermore, the configuration of the above-described embodiment is suitable for hybrid vehicles equipped with fuel cells (polymer electrolyte fuel cells, solid oxide fuel cells, etc.), or series hybrid vehicles equipped with an engine that is driven for power generation. It can also be applied to an electric vehicle 100 equipped with a power generator that generates drive power for the motor 4 .

In the above-described embodiment, the threshold vehicle speed V _th is set to the jerk fixed value k _j set in the first jerk adjustment process and the jerk j set in the second jerk adjustment process. An example of setting the vehicle speed reference value _Vk , which is the value of the vehicle speed V that matches _kj , has been described. However, the threshold vehicle speed V _th is not limited to being set to a vehicle speed V at which the jerk fixed value k _j of the first jerk adjustment process and the jerk j(t) of the second jerk adjustment process exactly match. You can set it with a width of . For example, the difference between the jerk j in the second jerk adjustment process and the jerk fixed value k _j in the first jerk adjustment process before and after the gain switching timing becomes a predetermined value that does not give the passenger a sudden stop feeling. The value of the vehicle speed V at time may be set as the threshold vehicle speed _Vth .

Claims (4)

An electric vehicle control method for executing stop control for decelerating and stopping an electric vehicle by regenerative braking force of an electric motor,
The stop control is
a first jerk adjustment process for adjusting the jerk of the electric vehicle to be equal to or less than a predetermined upper limit when the vehicle speed of the electric vehicle exceeds a threshold vehicle speed;
When the vehicle speed is equal to or lower than the threshold vehicle speed, a second jump for adjusting the jerk so that the deceleration of the electric vehicle and the jerk take on a profile that gradually approaches 0 and decreases as the vehicle speed decreases. and a degree adjustment process,
The threshold vehicle speed is the value of the vehicle speed when the difference between the jerk set in the second jerk adjustment process and the jerk set in the first jerk adjustment process is equal to or less than a predetermined value. is set,
Electric vehicle control method. The electric vehicle control method according to claim 1,
The stop control includes a motor torque command value setting step of setting a motor torque command value corresponding to the regenerative braking force by multiplying a speed parameter proportional to the vehicle speed by a predetermined gain,
The first jerk adjustment process is executed by setting the gain to a variable value whose absolute value decreases as the vehicle speed increases,
The second jerk adjustment process is executed by setting the gain to a constant fixed value with respect to changes in the vehicle speed.
Electric vehicle control method. The electric vehicle control method according to claim 2,
setting the gain by referring to a vehicle speed-gain table in which the vehicle speed and the gain determined according to the vehicle speed are associated;
Electric vehicle control method. An electric vehicle control system including a stop control device that decelerates and stops an electric vehicle by regenerative braking force of an electric motor,
The stop control device includes:
a first jerk adjustment unit that adjusts the jerk of the electric vehicle to a predetermined upper limit value or less when the vehicle speed of the electric vehicle exceeds a threshold vehicle speed;
When the vehicle speed is equal to or lower than the threshold vehicle speed, a second jump for adjusting the jerk so that the deceleration of the electric vehicle and the jerk take on a profile in which the jerk asymptotically decreases to 0 as the vehicle speed decreases. and a degree adjusting unit,
The threshold vehicle speed is the value of the vehicle speed when the difference between the jerk set by the second jerk adjustment unit and the jerk set by the first jerk adjustment unit is equal to or less than a predetermined value. set,
Electric vehicle control system.

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