BR112019025363B1 - CONTROL METHOD AND CONTROL DEVICE FOR ELECTRIC VEHICLE - Google Patents

Abstract

The control method for an electric vehicle sets a motor torque command value based on vehicle information and controls the torque of a first motor connected to a first drive wheel that is one of a front drive wheel and a front drive wheel. rear drive. The control method for an electric vehicle calculates a first torque command value by means of a feedforward computation based on the motor torque command value, detects an angular velocity of rotation of the first motor, and estimates an angular velocity of rotation of the first engine based on the first torque command value using a Gp(s) vehicle model that simulates a transfer characteristic of a torque input to the first drive wheel for an angular speed of rotation of the first engine. Then, the control device calculates a second torque command value from a deviation between a detected value and an estimated value of the rotational angular speed of the first motor using a composite Hf(s)óGp(s) filter. of an inverse characteristic (...).

Description

FIELD OF TECHNIQUE

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

BACKGROUND OF THE TECHNIQUE

[002] Conventionally, a vibration damping control device for an electric vehicle is known that has a function of removing vibration due to torsion of a drive shaft by calculating a motor torque command value with the use of a feed-back control system that includes a feed-forward compensator (F/F) and a feed-back compensator (F/B) (see document JP 2003-9566A).

SUMMARY OF THE INVENTION

[003] In the present document, the feedback control system of the vibration damping control device disclosed in document JP 2003-9566A estimates an engine rotational angular velocity of a control object using a vehicle model that models a transfer characteristic of an engine torque to an engine rotational angular speed, and calculates a feedback torque based on a deviation between an estimated value and a detected value of the engine rotational angular speed.

[004] However, since the vehicle model described above is designed in place of a two-wheel drive vehicle, when a braking/drive force (braking/drive touch) is input from a drive wheel different, the estimated value of the engine rotational angular velocity calculated by the vehicle model and the actual engine rotational angular velocity differ from each other. Therefore, there are cases where, in order to compensate for this divergence, a greater than necessary vibration suppression compensation value is output from the F/B compensator, resulting in the fact that the intended acceleration or deceleration of a driver is not can be obtained.

[005] It is an object of the present invention to suppress the output of an excess vibration suppression compensation value from an F/B compensator by causing an estimated value of the engine rotational angular velocity and a rotational angular velocity of actual engine coincide with each other, even when braking/drive force is input from a different drive wheel.

[006] The control method for an electric vehicle of an embodiment of the present invention is a method for an electric vehicle that sets a motor torque command value based on vehicle information and controls the torque of a first motor connected to a first drive wheel that is one of a front drive wheel and a rear drive wheel. The control method for an electric vehicle sets a motor torque command value based on vehicle information and controls the torque of a first motor connected to a first drive wheel that is one of a front drive wheel and a front drive wheel. rear drive. The control method for an electric vehicle calculates a first torque command value by means of a feedforward computation based on the motor torque command value, detects an angular velocity of rotation of the first motor, and estimates an angular velocity of rotation of the first engine based on the first torque command value using a Gp(s) vehicle model that simulates a transfer characteristic of a torque input to the first drive wheel for an angular speed of rotation of the first engine. Then, the control device calculates a second torque command value from a deviation between a detected value and an estimated value of the rotational angular speed of the first motor using a Hf(s)/Gp(s) filter. composed of an inverse characteristic of the vehicle model Gp(s) and a bandpass filter Hf(s) with a center frequency close to a vehicle torsional vibration frequency, controls the torque of the first motor according to a command value of front end torque obtained by adding the first torque command value and the second torque command value together, and corrects, when a braking/drive torque for a second drive wheel that is the drive wheel different from the first drive wheel is entered, the estimated value of the rotational angular speed of the first motor based on the braking/drive torque. This correction calculates a motor rotational angular velocity correction amount using a transfer function of the rotational angular velocity of the first motor to the second drive wheel, the transfer function modeled in advance, and corrects the estimated value of the rotational angular speed of the first engine based on the engine rotational angular speed correction amount.

[007] The following describes embodiments of the present invention in detail with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[008] Figure 1 is a block diagram illustrating a system configuration (system configuration 1) of an electric vehicle to which a control device of the present invention is applied;

[009] Figure 2 is a flowchart that illustrates the flow of processes carried out by an electric motor controller;

[010] Figure 3 is a diagram illustrating an example of a throttle position torque table (throttle opening degree);

[011] Figure 4 is a block diagram illustrating a system configuration (system configuration 2) of an electric vehicle to which a control device of the present invention is applied;

[012] Figure 5 is a flowchart that illustrates the flow of processes carried out by an electric motor controller;

[013] Figure 6 is a diagram explaining a longitudinal drive force distribution process;

[014] Figure 7 is a diagram that explains the equation of motion of a 4WD vehicle;

[015] Figure 8 is a block configuration diagram that performs the vibration damping control computing process of a first modality;

[016] Figure 9 is a time graph illustrating an example of the control results when control devices of the first, second and fourth embodiments are applied to electric vehicles, and the control results, in accordance with the prior art;

[017] Figure 10 is a block configuration diagram that realizes a vibration damping control computing process of the second embodiment;

[018] Figure 11 is a block configuration diagram illustrating a 4WD vehicle model of the second embodiment;

[019] Figure 12 is a block configuration diagram illustrating a front F/F compensator of the second embodiment;

[020] Figure 13 is a block configuration diagram illustrating front and rear F/F compensators of the second embodiment;

[021] Figure 14 is a block configuration diagram illustrating a rear F/F compensator of the second embodiment;

[022] Figure 15 is a diagram that explains the equation of motion of a 2WD vehicle;

[023] Figure 16 is a block configuration diagram that realizes a vibration damping control computing process of a third modality;

[024] Figure 17 is a block configuration diagram illustrating an F/F compensator of the third embodiment;

[025] Figure 18 is a block configuration diagram illustrating an F/B compensator of the third embodiment;

[026] Figure 19 is a time graph illustrating an example of the control results when a control device of the third modality is applied to an electric vehicle, and the control results, in accordance with the prior art;

[027] Figure 20 is a block configuration diagram that realizes a vibration damping control computing process of the fourth modality; It is

[028] Figure 21 is a block configuration diagram illustrating an F/F compensator of the fourth embodiment.

METHOD FOR CARRYING OUT THE INVENTION

[029] First, system configurations (system configuration 1, system configuration 2) of electric vehicles to which control devices for electric vehicles according to the present invention are applied will be described.

SYSTEM SETUP 1

[030] Figure 1 is a block diagram illustrating a main system configuration (system configuration 1) of an electric vehicle to which a control device of the present invention is applied; Note that electric vehicle refers to an automobile that includes at least one electric motor (hereinafter also called simply engine) as a part or entire vehicle drive source and capable of moving by means of a driving force from the electric motor and it can be an electric car or a hybrid car.

[031] A battery 1 discharges electrical drive power to an electric motor 4 and is charged with regenerative electrical power from the electric motor 4.

[032] An electric motor controller 2 includes, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM) and an input/output interface (I interface). /O). The signals of various vehicle variables indicating vehicle status, such as a vehicle speed V, a throttle position θ, a rotor phase α of the electric motor 4, currents (iu, iv, iw in the case of three-phase alternating current ) of the electric motor 4 and a braking/drive force command value are input to the electric motor controller 2 as digital signals. Based on the input signals, the electric motor controller 2 generates a PWM signal to control the electric motor 4. Furthermore, the electric motor controller 2 generates a drive signal for an inverter 3 based on the generated PWM signal. Note that as the brake/drive force command value, you can use a brake/drive force command value that indicates a braking/drive force (brake/drive torque) that acts on the vehicle in addition to the motor 4 of system configuration 1, such as braking output or motor, or, for example, one may use a measured value detected by a sensor, such as a brake pressure sensor, or the like.

[033] Inverter 3 converts or inverts the direct current supplied from the battery 1 into alternating current by turning on/off two switching elements (e.g., power semiconductor devices such as IGBTs or MOSFETs) provided for each phase, thereby causing the desired current to flow through the electric motor 4.

[034] The electric motor (three-phase AC motor) 4 generates a drive force by the alternating current supplied from the inverter 3 and transmits the drive force to all left and right drive wheels 9 through a speed reducer 5 and shafts drive wheel 8. On the other hand, when turned by the rotation of the drive wheels 9a, 9b during the movement of the vehicle, the electric motor 4 generates a regenerative drive force to recover the kinetic energy of the vehicle as electrical energy. In this case, inverter 3 converts the alternating current generated during the regenerative operation of the electric motor 4 into direct current and supplies the direct current to the battery 1.

[035] A current sensor 7 detects three-phase alternating currents iu, iv, iw flowing through the electric motor 4. However, since the sum of the three-phase alternating currents iu, iv, iw is zero, the currents of the two arbitrary phases can be detected, and then the remaining phase current can be obtained by calculation.

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

[037] Figure 2 is a flowchart illustrating the flow of processes performed by the electric motor controller 2. The processes from step S201 to step S205 are programmed to be performed constantly at a fixed time interval while the vehicle system is in operation. operation.

[038] In step S201, signals indicating vehicle states are input to the electric motor controller 2. In this document, a vehicle speed V (km/h), a throttle position θ (%), a phase of rotor α (rad) of the electric motor 4, a rotational speed Nm (rpm) of the electric motor 4, a three-phase alternating currents iu, iv, iw flowing through the electric motor 4, a DC voltage value Vdc (V) of battery 1, and a brake/drive force command value are entered.

[039] Vehicle speed V (km/h) is acquired from a non-illustrated vehicle speed sensor or from another non-illustrated controller via communication. Alternatively, the electric motor controller 2 obtains a vehicle speed v (m/s) by multiplying a rotor mechanical angular speed ram by a dynamic tire radius r and dividing the product by a gear ratio of a final gear. and then multiplies the vehicle speed v (m/s) by 3,600/1,000 to perform unit conversion, thus obtaining a vehicle speed V (km/h).

[040] The electric motor controller 2 acquires the throttle position θ (%) from a throttle position sensor not illustrated. Throttle position θ (%) can be acquired from another controller, such as a vehicle controller not shown.

[041] The rotor phase α (rad) of the electric motor 4 is acquired from the rotation sensor 6. The rotation speed Nm (rpm) of the electric motor 4 is obtained by dividing a rotor angular speed o (electric angle) by the number of pole parts P of the electric motor to obtain a motor rotation speed om (rad/s) which is a mechanical angular speed of the electric motor 4, and then multiplying the obtained motor rotation speed om by 60/(2π). The rotor angular velocity o is obtained by differentiating the rotor phase α.

[042] The currents iu, iv, iw (A) flowing through the electric motor 4 are acquired from the current sensor 7.

[043] The DC current value Vdc (V) is detected by a voltage sensor (not illustrated) provided on a DC power line between battery 1 and inverter 3. Note that the DC voltage value Vdc (V) can be detected by a signal transmitted from a battery controller (not illustrated).

[044] The braking/drive force command value may be a braking torque calculated from a value of a hydraulic pressure sensor attached to a brake system not illustrated, or may be acquired by communication from another controller ( not illustrated) that inserts a braking/drive force into the vehicle, different from engine 4 of system configuration 1.

[045] In step S202, based on vehicle information, the electric motor controller 2 sets a torque command value Tm* as a basic target torque required by a driver. Specifically, based on the throttle position θ and vehicle speed V entered in step S201, the electric motor controller 2 sets the torque command value Tm* by referring to a throttle position torque table illustrated in Figure 3.

[046] In step S203, the electric motor controller 2 performs a vibration damping control computing process. Specifically, based on the target torque command value Tm* set in step S202 and the motor rotation speed ©m, the electric motor controller 2 calculates a final torque command value Tmf* after vibration damping control which suppresses vibration of drive force transmission system (torsional vibration of drive shafts 8, etc.) without wasting drive shaft torque. The details of the vibration damping control computation process will be described later.

[047] In step S204, the electric motor controller 2 performs a current command value calculation process. Specifically, the electric motor controller 2 obtains a target axis current value d id* and a target axis current value q iq* based on the final torque command value Tmf* calculated in step S203, at speed of motor rotation ©m and the DC voltage value Vdc. For example, a table that defines the relationship between the torque command value, the motor rotation speed and the DC voltage value, and the target value of geometry axis current d and the target value of geometry axis current q is prepared in advance, and with reference to this table, the target axis current value d id* and the target axis current value q iq* are obtained.

[048] In step S205, current control to cause a d id geometry axis current and a q iq geometry axis current to coincide respectively with the d id* geometry axis current target value and the current target value of geometric axis q iq* obtained in step S204 is performed. Consequently, first, the axis current d id and the axis current q iq are obtained based on the three-phase alternating current values iu, iv, iw and the rotor phase α of the electric motor 4 that were entered in step S201 . Subsequently, the d-axis and q-axis voltage command values vd, vq are calculated from deviations between the d-axis current command values and q-axis id*, iq* and the d-axis currents and geometric axis q id, iq. In this document, there are cases where decoupling control is applied to the calculated geometry axis voltage command values d and geometry axis q vd, vq.

[049] Then, three-phase AC voltage command values vu, vv, vw are obtained from the voltage command values of geometric axis d and geometric axis q vd, vq and the rotor phase α of the electric motor 4. Then, the PWM signals tu (%), tv (%), tw (%) are obtained from the obtained three-phase AC voltage command values vu, vv, vw and the DC voltage value Vdc. By opening and closing the switching elements of the inverter 3 according to the PWM signals tu, tv, tw obtained, in this way it is possible to drive the electric motor 4 by means of a desired torque indicated by the target torque command value Tm *.

SYSTEM SETUP 2

[050] Figure 4 is a block diagram illustrating a main system configuration (system configuration 2) of an electric vehicle to which a control device in accordance with the present invention is applied, wherein the electric vehicle differs from the electric vehicle that includes system configuration 1 described above.

[051] A battery 1fr discharges electrical drive power into a front drive motor 4f and a rear drive motor 4e and is charged with regenerative electrical power from the front drive motor 4f and the rear drive motor 4r.

[052] The signals of various vehicle variables that indicate vehicle states, such as a vehicle speed V, a throttle position θ, a rotor phase αf of the front drive motor 4f, a rotor phase αr of the front drive motor rear drive 4r, currents (iu, iv, iw in the case of three-phase alternating current) from the front drive motor 4f, and currents (iu, iv, iw in the case of three-phase alternating current) from the rear drive motor 4r are inserted into a 2fr electric motor controller as digital signals. Based on the input signals, the 2fr electric motor controller generates PWM signals to respectively control the 4f front drive motor and 4r rear drive motor. Furthermore, the electric motor controller 2fr generates drive signals for a front inverter 3f and a rear inverter 3r based on the respective generated PWM signals.

[053] The front inverter 3f and the rear inverter 3r (hereinafter also referred to collectively as front/rear inverters 3f, 3r) each convert or invert the direct current supplied from the 1fr battery into alternating current by switching on/off Two switching elements (e.g., power semiconductor devices such as IGBTs or MOSFETs) are provided for each phase, thereby causing the desired currents to flow through the front drive motor 4f and the rear drive motor 4r.

[054] The front drive motor 4f (three-phase AC motor) and the rear drive motor 4r (three-phase AC motor) (hereinafter also collectively called front/rear drive motors 4f, 4r) generate drive forces via the currents alternating inputs supplied from the front/rear drives 3f, 3r and transmit the drive forces to the front drive wheels 9f and rear drive wheels 9r (hereinafter also collectively called front/rear drive wheels 9f, 9r) via a front speed reducer 5fr and a rear speed reducer 5r, and front drive shafts 8f and rear drive shafts 8r. On the other hand, when turned by the rotation of the front/rear drive wheels 9f, 9r during vehicle travel, the front/rear drive motors 4f, 4r generate regenerative drive forces to recover the vehicle's kinetic energy as electrical energy. In this case, the front/rear inverters 3f, 3r each convert the alternating current generated during regenerative operation into direct current and each supply the direct current to the 1fr battery.

[055] Note that the front drive wheels 9f mentioned in this specification represent the left and right drive wheels at the front of the vehicle, and the rear drive wheels 9r represent the left and right drive wheels at the rear of the vehicle.

[056] A front rotation sensor 6f and a rear rotation sensor 6r are, for example, resolvers or encoders and respectively detect rotor phases αf, αr of the front/rear drive motors 4f, 4r.

[057] Figure 5 is a flowchart that illustrates the flow of processes carried out by the 2fr electric motor controller. The processes from step S501 to step S505 are scheduled to be carried out constantly at a fixed time interval while the vehicle system is in operation.

[058] In step S501, as in system configuration 1 described above, signals from the front and rear configurations required for vibration damping control computation, which will be described below, are acquired from sensor inputs or other communication controller.

[059] In step S502, based on vehicle information, the electric motor controller 2fr sets a torque command value Tm* as a basic target torque required by a driver. Specifically, based on a throttle position θ and a vehicle speed V entered in step S501, the 2fr electric motor controller sets the torque command value Tm* by referring to the throttle position torque table illustrated in Figure 3. Then, the 2fr electric motor controller performs the longitudinal drive force distribution process to calculate a front target torque command value Tm1* and a rear target torque command value Tmr1*.

[060] Figure 6 is a diagram that explains the longitudinal drive force distribution process. In Figure, Kf is a value for distributing a drive force, which is output according to the torque command value Tm* as the required driver torque, to the front drive motor 4f and the rear drive motor 4r and is set to a value from 0 to 1. The 2fr electric motor controller calculates the front target torque command value Tm1* for the front drive system by multiplying the torque command value Tm* by Kf set as the value from 0 to 1. Simultaneously, the 2fr electric motor controller calculates the rear target torque command value Tmr1 for the rear drive system by multiplying the torque command value Tm* by 1-Kf.

[061] In step S503, the electric motor controller 2fr performs a vibration damping control computing process. In this step, using as an input the front target torque command value Tm1* calculated in step S502, the front drive system of system configuration 2 calculates a front end torque command value Tmf* that suppresses drive system vibration. drive force transmission (torsional vibration of front drive shafts 8f, etc.).

[062] Likewise, using as an input the rear target torque command value Tmr1 calculated in step S502, the rear drive system calculates a rear end torque command value Tmrf* that suppresses vibration of the power transmission system. drive (torsional vibration of rear drive shafts 8r, etc.). Details of the vibration damping control computing process, which is a feature of the present invention, will be described later.

[063] In step S504, as in system configuration 1, the electric motor controller 2fr performs a current command value calculation process. Specifically, the 2fr electric motor controller obtains target geoaxis current values d id* and target geoaxis current values q iq* from the front/rear drive motors 4f, 4r based on the front end torque command values and rear Tmf*, Tmrf* calculated in step S503, front and rear motor rotational angular speeds ©mf, ©mr and a DC voltage value Vdc.

[064] In step S505, as in system configuration 1, the electric motor controller 2fr performs current control. More specifically, the electric motor controller 2fr opens and closes the switching elements of the front/rear inverters 3f, 3r in accordance with PWM signals for the front and rear drive systems obtained in the same manner described in system configuration 1, so that it is possible to drive the front/rear drive motors 4f, 4r by means of desired torques indicated by the front and rear final torque command values Tmf*, Tmrf*.

[065] The aforementioned are the electric vehicle system configurations to which the electric vehicle control devices in accordance with the present invention are applied, and the outline of the processes performed by the controllers (the electric motor controller 2 and the electric motor controller 2fr) included in the respective systems. Hereinafter, embodiments of the present invention will be described primarily with respect to the details of the vibration damping control computing processes that are the features of the present invention.

FIRST MODE

[066] It is assumed that a control device for an electric vehicle of this modality is applied to the system configuration 2 described above. Hereinafter, details of the vibration damping control process that is carried out in step S503 described above by the control device for an electric vehicle of the first embodiment will be described. Note that the vibration damping control process is carried out for the purpose of removing vibration (suppression) mainly caused by the torsion of the drive shafts in the vehicle's drive force transmission system.

[067] First, the equation of motion of a front torque command value for a vehicle front engine rotational angular velocity that includes the drive motors, respectively for the front and rear drive wheels (system configuration 2, see Figure 4) will be described with reference to Figure 7.

[068] Figure 7 is a diagram that models the vehicle drive force transmission system, according to system configuration 2 (hereinafter also called 4WD vehicle), and the respective parameters in the same Figure are as follows . Note that the auxiliary symbols f and r represent front and rear respectively. Jmf, Jmr : engine inertia Jwf, Jwr : drive wheel inertia (for one axle) Kdf, Kdr : torsional stiffness of drive system Ktf, Ktr : coefficient for friction between tire and road surface Nf, Nr : total gear ratio rf, rr : tire loaded radius ®mf, wmr : angular speed of rotation of motor θmf, θmr : angle of rotation of motor ®wf, wwr : angular speed of rotation of drive wheel θwf, θwr : angle of drive wheel rotation Tmf, Tmr : engine torque Tdf, Tdr : drive shaft torque Ff, Fr : drive force (for two axles) θdf, θdr : drive shaft twist angle V : body speed of vehicle M: vehicle body weight

[069] From Figure 7, the equation of motion of the 4WD vehicle is given by the following formulas (1) to (11). FORMULA 1 FORMULA 2 FORMULA 3 FORMULA 4 FORMULA 5 FORMULA 6 FORMULA 7 FORMULA 8 FORMULA 9 FORMULA 10 FORMULA 11

[070] By means of the Laplace transform of the above formulas (1) to (11), a transfer characteristic from a front motor torque Tmf to a front motor rotational angular speed wmf is obtained as given by the following formula (12). FORMULA 12

[071] where the parameters in formula (12) are respectively provided by the following formulas (13) to (17). FORMULA 13 FORMULA 14 FORMULA 15 FORMULA 16 FORMULA 17

[072] The poles and zero points of the transfer function provided by formula (12) are examined, and the following formula (18) is obtained. FORMULA 18

[073] Since α and a, β and β', Çpr and Çpr', and opr and opr' in formula (18) take very close values, a transfer characteristic (second order)/(third order) Gp( s) as given by the following formula (19) can be obtained by pole zero cancellation (approximation of α=α', β=β', Çpr=Çpr', opr=opr'). FORMULA 19

[074] As a result, in relation to the equation of motion of the 4WD vehicle, the transfer characteristic of the front engine torque to the front engine rotational angular velocity can be approximated to the vehicle model Gp(s) provided by the second formula order/third order (hereinafter also called 4WD Gp(s) vehicle model).

[075] In this document, in relation to the vehicle model Gp(s), when the model response that restricts torsional vibration due to the front drive shafts 8f is provided by the following formula (20), a direct feed compensator ( a front F/F compensator 801, see Figure 8) that restrains the torsional vibration of the front drive system is provided by the following formula (21). FORMULA 20 FORMULA 21

[076] Likewise, a transfer characteristic of a rear engine torque Tmr to a rear engine rotational angular speed <amr is obtained as provided by the following formula (22). FORMULA 22

[077] In the present document, in relation to the vehicle model Gpr(s), when a model response that restricts torsional vibration due to the rear drive shafts 8r is provided by the following formula (23), an F/F compensator ( a rear F/F compensator 805, see Figure 8) that restrains the torsional vibration of the rear drive system is given by the following formula (24). FORMULA 23 FORMULA 24

[078] Subsequently, the equation of motion of the 4WD vehicle from a rear end torque command value Tmf to a front engine rotation angular speed <amf will be specifically described with reference to Figure 7.

[079] By means of the Laplace transform of the above formulas (1) to (11), a transfer characteristic from a rear engine torque command value as a braking/drive torque for the rear drive wheels to a front engine rotational angular velocity is obtained by the following formula (25). Note that the parameters in formula (22) are respectively given by the above formulas (13) to (17). FORMULA 25

[080] The poles of the transfer function provided by formula (25) are examined and provided by the following formula (26). FORMULA 26

[081 ] in which, since α and β of the poles of formula (26) are located far from the origin and dominant poles, the influence on the vehicle model provided by Gprf(s) is small. Therefore, formula (26) can be approximated to a transfer function given by the following formula (27). FORMULA 27

[082] Furthermore, when a rear vibration damping control algorithm is considered for the Gprf(s) vehicle model, a transfer function is obtained as provided by the following formula (28). FORMULA 28

[083] Then, in order to constrain the torsional vibration of the front drive system from a model response of an estimated value of the engine rotational angular velocity of the front drive system, a transfer function of the following formula (29 ) is derived from the transfer function of formula (28). FORMULA 29

[084] Likewise, a transfer characteristic of a front final torque command value Tmf to a rear engine rotation angular speed <amr is provided by a formula (30). FORMULA 30

[085] in which, since α and β of the poles of formula (30) are located far from the origin and dominant poles, the influence on the vehicle model provided by Gpfr(s) is small. Therefore, formula (30) can be approximated to a transfer function given by the following formula (31). FORMULA 31

[086] Furthermore, when a frontal vibration damping control algorithm is considered for the Gpfr(s) vehicle model, a transfer function is obtained as provided by the following formula (32). FORMULA 32

[087] Then, in order to constrain the torsional vibration of the rear drive system from a model response of an estimated value of the engine rotational angular velocity of the rear drive system, a transfer function of the following formula (33 ) is derived from the transfer function of formula (32). FORMULA 33

[088] The vibration damping control computing process that is carried out using the vehicle models (transfer functions) described above will be described with reference to Figure 8.

[089] Figure 8 is an example of a block configuration diagram that performs the vibration damping control computing process of the first embodiment. In the control blocks illustrated in Figure 8, a front end torque command value Tmf* is calculated from a front target torque command value Tm1*, a front engine rotation angular speed «mf and a command value of rear target torque Tmr1*. Furthermore, a rear end torque command value Tmrf* is calculated from a rear target torque command value Tmr1*, a rear engine rotational angular velocity <amr, and a front target torque command value Tm1*. Hereinafter, details of the respective control blocks illustrated in Figure 8 will be described.

[090] The front F/F compensator 801 is composed of the Gr(s)/Gp(s) filter provided by the above formula (21). The front F/F compensator 801 calculates a first torque command value using the front target torque command value Tm1* as an input and performs an F/F compensation process by the above formula (21).

[091] An adder 809 adds the first torque command value and a second torque command value described later to calculate the front end torque command value Tmf*.

[092] A control block 802 is composed of the vehicle model Gp(s) provided by the above formula (12). The control block 802 calculates an estimated value of the front engine rotational angular velocity using the front end torque command value Tmf* as an input and using the vehicle model Gp(s).

[093] A control block 803 is composed of the vehicle model Gprf(s) provided by the above formula (25). The control block 803 calculates an estimated correction front engine rotational velocity value as an engine rotational angular velocity correction amount using, as an input, the rear target torque command value Tmr1* as a braking/drive torque for the rear drive wheels and using vehicle model Gprf(s). Note that, like the Gprf(s) vehicle model, any of formulas (26) to (28), each being the approximate formula of the above formula (25), can be used to reduce the software computation load of the electric motor controller 2fr.

[094] An adder 810 adds the estimated correction front motor rotational angular velocity value as the output of the control block 803 to the estimated value of the front motor rotational angular velocity as the output of the control block 802 to calculate a estimated corrected front engine rotational angular velocity value that is corrected in consideration of the braking/drive force for the rear drive wheels. Consequently, it is possible to make an estimated value and a detected value of the front engine rotational angular velocity coincide with each other.

[095] A subtractor 811 subtracts the engine rotational angular velocity <amf (detected value) from the estimated corrected front engine rotational angular velocity value to calculate a deviation between the estimated value and the detected value of the front engine rotational angular velocity. motor and outputs the calculated value to an 804 control block.

[096] The control block 804 is composed of a bandpass filter Hf(s) and an inverse characteristic of the vehicle model Gp(s) provided by the above formula (19). Control block 804 calculates the second torque command value using as an input the deviation between the estimated value and the detected value of the engine rotational angular speed and multiplies the deviation by Hf(s)/Gp(s ). Details of the Hf(s) bandpass filter will be described later.

[097] Then, the first torque command value and the second torque command value are added together by adder 809 so that the front end torque command value Tmf* is calculated.

[098] Next, the calculation of the rear final torque command value Tmrf will be described. The rear F/F compensator 805 is composed of the filter provided by the above formula (24). The rear F/F compensator 805 calculates a third torque command value using the rear target torque command value Tmr1* as an input and performs an F/F compensation process by the above formula (24).

[099] An adder 812 adds the third torque command value and a fourth torque command value described later to calculate the rear end torque command value Tmrf*.

[0100] A control block 806 is composed of the vehicle model Gpr(s) provided by the above formula (22). The control block 806 calculates an estimated rear engine rotational angular velocity value using the rear end torque command value Tmrf* as an input and using the vehicle model Gpr(s).

[0101] A control block 807 is composed of the vehicle model Gpfr(s) provided by the above formula (30). The control block 807 calculates an estimated correction rear engine rotational angular velocity value using the front target torque command value Tm1* as an input and using the vehicle model Gpfr(s). Note that, like the Gpfr(s) vehicle model, any of formulas (31) to (33), each being the approximate formula of the above formula (30), can be used to reduce the software computation load of the electric motor controller 2fr.

[0102] An adder 813 adds the estimated correction rear engine rotational angular velocity value as the output of the control block 807 to the estimated value of the rear engine rotational angular velocity as the output of the control block 806 to calculate a estimated corrected rear engine rotational angular velocity value that is corrected in consideration of braking/drive force for the front drive wheels. Consequently, it is possible to make an estimated value and a detected value of the rear engine rotational angular velocity coincide with each other.

[0103] A subtractor 814 subtracts the rear engine rotational angular velocity <amr (sensed value) from the estimated corrected rear engine rotational angular velocity value to calculate a deviation between the estimated value and the detected value of the rotational angular velocity rear engine and outputs the calculated value to an 808 control block.

[0104] The control block 808 is composed of a bandpass filter Hr(s) and an inverse characteristic of the vehicle model Gpr(s) provided by the above formula (22). The control block 808 calculates the fourth torque command value using as an input the deviation between the estimated value and the detected value of the engine rotational angular speed and multiplies the deviation by Hr(s)/Gpr(s ). Details of the Hr(s) bandpass filter will be described later.

[0105] Then, the first torque command value and the second torque command value are added together by adder 812 so that the rear end torque command value Tmrf* is calculated.

[0106] In this document, the front and rear bandpass filters Hf(s), Hr(s) will be described. The damping characteristics of each of the bandpass filters Hf(s), Hr(s) are approximately equal on the low-pass side and the high-pass side, and the torsional resonance frequency fp of each of the drive systems is defined near the middle of the passband on the logarithmic axis (log scale).

[0107] For example, when the Hf(s), Hr(s) bandpass filters are each composed of a first-order low-pass filter and a first-order low-pass filter, the band Hf(s) is obtained as given by the following formula (34), and the bandpass filter Hr is obtained as given by the following formula (35). FORMULA 34

[0108] where TLÍ = 1/(2πfHCf), ÍHOÍ = kf • fpf, THÍ = 1/(2πfLCf) and fLCf = fpf/kf. The fpf frequency is a torsional resonance frequency of the drive system of the front drive system, and kf is an arbitrary value that forms the bandpass. FORMULA 35

[0109] where TLr = 1/(2πfHCr), fHCr = kr • fpr, ?Hr = 1/(2πfLCr) and fLCr = fpr/kr. The frequency fpr is a torsional resonance frequency of the drive system of the rear drive system, and kr is an arbitrary value that forms the bandpass.

[0110] In the present document, the computing results of vibration damping control by the control device for an electric vehicle of the first embodiment will be described with reference to Figure 9.

[0111] Figure 9 is a time graph for comparing the control results by electric vehicle control devices of the first embodiment and the second and fourth embodiments described later and the control results according to the prior art. In Figure, a front end torque command value Tmf*, a rear end torque command value Tmrf*, a second torque command value as a front vibration damping torque F/B, a fourth torque command value as a torque as a rear vibration damping F/B torque, a longitudinal acceleration of a vehicle, and an enlarged view of the longitudinal acceleration are respectively illustrated in that order from above. In the Figure, solid lines indicate control results according to the first, second and fourth embodiments, and dashed lines indicate control results according to the prior art.

[0112] Figure 9 illustrates a control state of a vehicle, which is a 4WD electric vehicle that includes electric motors as power sources not only for front drive wheels, but also for rear drive wheels, when a driver quickly presses an accelerator from a stationary state of the vehicle, so that the front target torque command value and the rear target torque command value are increased by one step to accelerate the vehicle.

[0113] First, at time t1, the front target torque command value and the rear target torque command value are changed by one step by the driver pressing the accelerator pedal.

[0114] Then, in the prior art (dashed lines), since only one of the front and rear braking/drive forces is considered, the actual detected values become greater than the estimated front/engine rotational speed values. rear wheel calculated by a feedback control system that corresponds to an addition of a drive force by the other drive wheels. Then, in order to compensate for a torque that corresponds to a detected motor rotation speed greater than the estimated one, the torque command value is corrected on the negative torque side (in a direction to reduce the motor torque) to prevent ac from time t1 to t3 (see second and fourth torque command values). Therefore, the front end torque command value Tmf* and the rear end torque command value Tmrf* cannot be output as torque command values required by the driver. As a result, it is observed that the longitudinal acceleration (acceleration) of the vehicle is limited around time t2 compared to that at time t3 (see particularly LONGITUDINAL acceleration (ENLARGED VIEW)).

[0115] Thus, in the prior art, since excess vibration compensation is emitted from an F/B compensator to prevent the vehicle from accelerating, it is not possible to achieve a driver's intended acceleration or deceleration based on an accelerator operation or a brake operation by the driver and therefore a feeling of incongruity is provided for the driver.

[0116] In contrast, according to the control device for an electric vehicle of the first embodiment (solid lines), even when the front and rear target torque command values are changed by one step in time t1, the second value of torque command and the fourth torque command value are zero from time t1 to t3. It can be said to be a state in which an estimated value and a detected value of the engine rotational angular speed coincide with each other. Therefore, according to the control device for an electric vehicle of the first embodiment, it can be suppressed that excess vibration suppression compensation (negative torque) is emitted from the F/B compensator in order to compensate a component of torque corresponding to a difference between an estimated value and a detected value of the angular speed of rotation of the front engine in the feedback control system as in the prior art (dashed lines). Therefore, from time t1 to t3, the front end torque command value Tmf* and the rear end torque command value Tmrf* can both be output as the torque command values intended by the driver.

[0117] As a result, even during acceleration with the use of the front and rear drive wheels, it is possible to obtain an acceleration intended by the driver. This is the effect obtained by correcting the estimated value of engine rotational angular velocity using the filter configured based on the transfer function of the rear engine rotational angular velocity to the front drive wheels (or the front engine rotation to the rear drive wheels).

[0118] Although the control results on the drive side of the 4WD electric vehicle have been described, the control results during regenerative operation are the same. That is, in the prior art, when the electric 4WD vehicle is decelerated, the second torque command value and the fourth torque command value are corrected on the positive torque side by excess vibration suppression compensation, so that the deceleration is prevented and, therefore, it is not possible to achieve the deceleration intended by the driver. In contrast, according to the control device for an electric vehicle of the first embodiment, such as the control on the drive side described above, since it is possible to suppress the excess vibration suppression compensation output (positive torque) from of the vibration damping control F/B compensator, it is possible to carry out a deceleration desired by the driver.

[0119] As described above, the control device for an electric vehicle of the first embodiment is a device that realizes a control method for an electric vehicle that sets a motor torque command value based on vehicle information and controls the torque of a first motor (4f motor) connected to a first drive wheel which is a front drive wheel and a rear drive wheel (in this embodiment, the front drive wheel). The control device for an electric vehicle calculates a first torque command value by means of a forward computation based on the motor torque command value, detects an angular velocity of rotation of the first motor, and estimates an angular velocity of rotation of the first engine based on the first torque command value using a vehicle model Gp(s) that simulates a transfer characteristic of a torque input to the first drive wheel for an angular rotational speed of the first engine. Then, the control device calculates a second torque command value from a deviation between a detected value and an estimated value of the rotational angular speed of the first motor using a Hf(s)/Gp(s) filter. composed of an inverse characteristic of the vehicle model Gp(s) and a bandpass filter Hf(s) with a center frequency close to a vehicle torsional vibration frequency, controls the torque of the first motor according to a command value of front end torque obtained by adding the first torque command value and the second torque command value together, and corrects, when a braking/drive torque for a second drive wheel that is the drive wheel different from the first drive wheel is entered, the estimated value of the rotational angular speed of the first motor based on the braking/drive torque. This correction calculates a motor rotational angular velocity correction amount using a rotational angular velocity transfer function from the first motor to the second drive wheel, the transfer function modeled in advance, and corrects the estimated value of the motor rotational velocity. rotational angular speed of the first engine based on the engine rotational angular speed correction amount.

[0120] Consequently, even when braking/drive torque is input from the rear drive wheel, the estimated value and the detected value of the front motor rotational angular velocity can be made to coincide with each other and , therefore, it is possible to suppress the excess vibration compensation that is emitted from the F/B compensator in order to compensate for a torque component that corresponds to a divergence between the estimated value and the detected value of the rotational angular velocity of front motor in the feedback control system.

SECOND MODE

[0121] It is assumed that a control device for an electric vehicle of this embodiment is applied to the system configuration 2 described above. Hereinafter, the vibration damping control computing process that is performed in step S503 described above by the control device for an electric vehicle of the second embodiment will be described with reference to Figure 10.

[0122] Figure 10 is an example of a block configuration diagram that realizes the vibration damping control computing process of the second embodiment. The control blocks illustrated in Figure 10 include a front F/F compensator 901, a rear F/F compensator 902, a 4WD vehicle model 903, a control block 904, a control block 905, adders 908, 909, and subtractors. 906, 907.

[0123] The front F/F compensator 901 is a filter that restricts the torsional vibration of the front drive shaft, and is composed of a Gr(s)/Gp(s) filter provided by the above formula (21). The front F/F compensator 901 calculates a first torque command value using a front target torque command value Tm1* as an input and performs an F/F compensation process by the above formula (21).

[0124] The rear F/F compensator 902 is a filter that restricts rear drive shaft torsional vibration, and is composed of a Grr(s)/Gpr(s) filter provided by the above formula (24). The rear F/F compensator 902 calculates a third torque command value using a rear target torque command value Tmr1* as an input and performs an F/F compensation process by the above formula (24).

[0125] 4WD vehicle model 903 calculates an estimated front engine rotational angular velocity value of mf and an estimated rear engine rotational angular velocity value ofmr using the first torque command value and the third value as inputs and using a vehicle model illustrated in Figure 11. As illustrated in Figure 11, the vehicle model used in this document is a vehicle model that simulates a torque drive force transmission system. a four-wheel drive vehicle (4WD vehicle) that has front drive wheels and rear drive wheels, that is, a feature of transferring torque inputs to the front drive wheels and the rear drive wheels for angular speeds of engine rotation of a front drive motor and a rear drive motor. The 4WD vehicle model 903 illustrated in Figure 11 is a block configuration diagram that is configured equivalent to the equation of motion (1) to (11) of the 4WD vehicle.

[0126] In the present document, in the illustrated 4WD vehicle model 903, a drive force Fr for the rear drive wheels calculated based on the third torque command value is added to a system that calculates the estimated value of the angular velocity of OFMF front engine speed based on first torque command value. Consequently, in the 4WD vehicle model, the estimated front engine rotational angular velocity value calculated based on the first torque command value can be corrected based on the third torque command value that indicates a braking/drive torque for the rear drive wheels.

[0127] Subtractor 906 illustrated in Figure 10 subtracts an engine rotational angular velocity <amf (detected value) estimated value of front engine rotational angular velocity <aAmf to calculate a deviation between the estimated value and the detected value of the speed engine rotation angle and outputs the calculated value to control block 904.

[0128] Control block 904 is composed of an Hf(s) bandpass filter provided by the above formula (34) and an inverse characteristic of a Gp(s) vehicle model provided by the above formula (19). Control block 804 calculates a second torque command value using as an input the deviation between the estimated value and the detected value of the engine rotational angular speed and multiplies the deviation by Hf(s)/Gp(s ).

[0129] Adder 908 adds the first torque command value and the second torque command value to calculate a front end torque command value Tmf*.

[0130] On the other hand, subtractor 907 subtracts an engine rotational angular velocity <amr (detected value) from the estimated value of rear engine rotational angular velocity ofmr to calculate a deviation between the estimated value and the detected value of the speed engine rotation angle and sends the calculated value to the 905 control block.

[0131] Control block 905 is composed of a bandpass filter Hr(s) provided by the above formula (35) and an inverse characteristic of the vehicle model Gp(s) provided by the above formula (19). Control block 804 calculates a fourth torque command value using as an input the deviation between the estimated value and the detected value of the engine rotational angular speed and multiplies the deviation by Hr(s)/Gpr(s ).

[0132] Adder 909 adds the first torque command value and the second torque command value to calculate a rear end torque command value Tmrf*.

[0133] In this document, when a drive shaft torsional resonance frequency fpf of the front drive system and a drive shaft torsional resonance frequency fpr of the rear drive system differ from each other (fpf * fpr), a model response of the F/F compensation process performed by the front F/F compensator 901 and a model response of the F/F compensation process performed by the rear F/F compensator 902 may be correlated with each other in order to correlate the responses of driving force from the front drive wheels and the rear drive wheels to each other. That is, as illustrated in Figure 12, taking into account a control block 1101 in the configuration of the front F/F compensator 901, the model response of the F/F compensation process performed by the front F/F compensator 901 and the Model response of the F/F compensation process performed by the rear F/F compensator 902 can be correlated with each other.

[0134] Consequently, the increase and decrease of front and rear torques when a driver performs an ON/OFF operation of an accelerator can be respectively correlated, so that it is possible to suppress the occurrence of two-step acceleration sensation due to the difference in response speeds of drive forces of the front and rear drive wheels. Furthermore, when designing a vibration damping control external loop control system, the design of the control system can be facilitated by correlating the model responses of the plurality of drive wheels to each other.

[0135] Control block 1101 is composed of a Gr(s)/Gp(s) filter provided by the following formula (36). FORMULA 36

[0136] Alternatively, when fpf * fpr, the front F/F compensator 901 and the rear F/F compensator 902 may be configured as illustrated in Figure 13 in order to correlate the drive force responses of the front drive wheels and the rear drive wheels to each other. That is, the front F/F compensator 901 and the rear F/F compensator 902 may each be composed of both the Gr(s)/Gp(s) filter that restricts front drive shaft torsional vibration, and the Grr(s)/Gpr(s) filter that restricts rear drive shaft torsional vibration. Furthermore, with this configuration, the model response of the F/F compensation process performed by the front F/F compensator 901 and the model response of the F/F compensation process performed by the rear F/F compensator 902 can be correlated in a with the other.

[0137] According to such a configuration, since the torsional vibration frequencies of the plurality of drive wheels are all damped, it is possible to suppress all drive shaft torsional vibration only by the front and rear F/F compensators 901, 902 .

[0138] When the drive shaft torsional resonance frequency fpf of the front drive system is lower than the drive shaft torsional resonance frequency fpr of the rear drive system (fpf < fpr), the F/F compensation process of the rear F/F compensator 902 on the high frequency side can be taken into account in the F/F compensation process side of the front F/F compensator 901 in order to correlate the response of front and rear drive wheel models to the characteristics on the low frequency side. That is, as illustrated in Figure 14, taking into account a control block 1201 in the configuration of the rear F/F compensator 902, the drive force responses of the front and rear drive wheels can be correlated to the characteristics on the side of lower frequency. The control block 1201 is composed of a Gr(s)/Grr(s) filter that has an inverse characteristic of a vehicle model Grr(s) given by the above formula (23) and a vehicle model Gr(s) given by the formula above (20).

[0139] In the present document, when the model responses of the plurality of drive wheels are correlated to the high frequency side, driver compensation is necessary for the drive wheels that have a drive shaft torsional vibration frequency characteristic on the low frequency side and therefore a torque command value that indicates a torque equal to or greater than a torque required by a driver is defined for these drive wheels. However, since there are upper and lower limits of torque or similar at wide open acceleration or similar, there are cases where when driver compensation is performed, a torque in accordance with the model response cannot be output. Therefore, in this embodiment, the model responses of the plurality of drive wheels are correlated to the low frequency side.

[0140] Through the rear end torque command value Tmrf* and the front end torque command value Tmf* calculated as described above, it is also possible to suppress the excess vibration compensation output from an F/B compensator of vibration damping control as indicated by the control results illustrated in Figure 9 described above (see the second embodiment in Figure) and therefore it is possible to obtain a driver's intended acceleration even during acceleration with the use of the drive wheels front and rear.

[0141] As described above, when the electric vehicle includes a second motor (rear drive motor) as a power source for the second drive wheel (rear drive wheel), the vehicle model Gp(s) is a model of a 4WD vehicle that simulates a transfer characteristic of torque inputs to the first drive wheel and the second drive wheel for engine rotational angular speeds of the first engine and the second engine, and the control device for an electric vehicle of the second embodiment calculates a third torque command value by a direct feed computation based on the motor torque command value, detects an angular rotational speed of the second motor, calculates a fourth torque command value from a deviation between a detected value and an estimated value of the rotational angular velocity of the second engine with the use of a Hr(s)/Gpr(s) filter composed of an inverse characteristic of a Gpr(s) vehicle model that simulates a characteristic of transfer of a torque input to the second drive wheel for an engine rotational angular speed of the second engine, and a bandpass filter Hr(s) with a center frequency close to a torsional vibration frequency of the vehicle, and controls the torque of the second motor according to a second final torque command value obtained by adding the third torque command value and the fourth torque command value together. Then, the control device calculates an estimated rotational angular velocity value of the first motor and an estimated rotational angular velocity value of the second motor using the first torque command value and the third torque command value as inputs. and with the use of the 4WD vehicle model, and corrects the estimated rotational angular velocity value of the first engine based on the third torque command value.

[0142] Consequently, even when braking/drive torque is input from the rear drive wheel, the estimated value and the detected value of the front engine rotational angular velocity can be made to coincide with each other with the use of 4WD vehicle model designed aiming at a plurality of drive wheels. Therefore, excess vibration suppression compensation can be suppressed from being output from the F/B compensator in order to compensate for a torque component that corresponds to a divergence between the estimated value and the detected value of the rotational angular velocity. of front motor in the feedback control system.

[0143] Furthermore, according to the control device for an electric vehicle of the second embodiment, when a drive shaft torsional vibration frequency of the first drive wheel (front drive wheel) and a drive shaft torsional vibration frequency drive of the second drive wheel (rear drive wheel) differ from each other, a template response used in forward feed computation that calculates the first torque command value and a template response used in forward feed computation that calculates the third torque command value are correlated to each other. Consequently, the rise and fall of front and rear torques when a driver performs an ON/OFF operation of an accelerator can be respectively correlated, so that it is possible to suppress the occurrence of two-step acceleration sensation due to the difference in response speeds. of driving forces of the front and rear drive wheels.

[0144] Furthermore, according to the control device for an electric vehicle of the second embodiment, the first torque command value can be calculated by direct power computation using a filter having a transfer characteristic that dampens the torsional vibration frequency of drive shaft of the first drive wheel (front drive wheel), and the third torque command value can be calculated by direct power computation with the use of a filter that has a transfer characteristic that dampens the torsional vibration frequency of drive shaft of the second drive wheel (rear drive wheel). Consequently, since the torsional vibration frequencies of the plurality of drive wheels are all damped, it is possible to suppress all drive shaft torsional vibration only by the front and rear F/F compensators.

[0145] Furthermore, according to the control method for an electric vehicle of the second embodiment, when the torsional vibration frequency of drive shaft of the second drive wheel (rear drive wheel) is lower than the torsional vibration frequency of drive shaft of the first drive wheel (front drive wheel), the model response used in the forward-feed computation that calculates the first torque command value is correlated to the model response used in the forward-feed computation that calculates the third torque command value. When the drive shaft torsional vibration frequency of the first drive wheel is lower than the drive shaft torsional vibration frequency of the second drive wheel, the model response used in forward power computation that calculates the third command value of torque is correlated to the model response used in the forward power computation that calculates the first torque command value. Consequently, the rise and fall of front and rear torques when a driver performs an ON/OFF operation of an accelerator can be respectively correlated without the need for driver compensation, so that it is possible to suppress the occurrence of two-step acceleration sensation. due to the difference in response speeds of drive forces of the front and rear drive wheels.

THIRD MODE

[0146] It is assumed that a control device for an electric vehicle of this embodiment is applied to the system configuration 1 described above. Hereinafter, the vibration damping control computing process that is performed in step S203 described above by the control device for an electric vehicle of the third embodiment will be described with reference to the drawings and so on.

[0147] First, a vehicle model used in the vibration damping control computing process in this embodiment will be described.

[0148] Figure 15 is a diagram that models the vehicle drive force transmission system of system configuration 1, and respective parameters in the same Figure are as follows. Jm : engine inertia Jw : drive wheel inertia (for one axle) M : vehicle body weight Kd : torsional stiffness of drive system Kt : coefficient for friction between tire and road surface N : gear ratio total r : loaded radius of tire om : angular velocity of rotation of motor θm : angle of rotation of motor ow : angular velocity of rotation of drive wheel θw : angle of rotation of drive wheel Tm : torque of motor Td : torque of drive shaft F : drive force (for two axles) V : vehicle body speed θd : drive shaft twist angle

[0149] From Figure 14, the equation of motion of the two-wheel drive vehicle (2WD vehicle) is given by the following formulas (37) to (42). FORMULA 37 FORMULA 38 FORMULA 39 FORMULA 40 FORMULA 41 FORMULA 42

[0150] By means of the Laplace transform of the above formulas (37) to (42), a transfer characteristic from a motor torque Tm to a motor rotational speed Hm is obtained as given by the following formulas (43) and (44). FORMULA 43 FORMULA 44

[0151] where a3, a2, a1, a0, b3, b2, b1 and b0 in formula (44) are respectively provided by the following formula (45). FORMULA 45

[0152] Furthermore, a transfer characteristic of the motor torque Tm to a drive shaft torque Td is provided by the following formula (46). FORMULA 46

[0153] where c1 and c2 in formula (46) are provided by the following formula (47). FORMULA 47

[0154] From formulas (38), (40), (41) and (42), a transfer characteristic from the motor rotation speed om to a drive wheel rotation angular speed ow is obtained as given by following formula (48). FORMULA 48

[0155] From formulas (43), (44) and (48), a transfer characteristic of the engine torque Tm to the drive wheel rotational angular speed ow is provided by the following formula (49). FORMULA 49

[0156] From formulas (46) and (49), a transfer characteristic of the drive shaft torque Td to the drive wheel rotational angular speed ow is provided by the following formula (50). FORMULA 50

[0157] In this document, formula (50) is transformed into the following formula (51). FORMULA 51

[0158] Therefore, from formulas (50) and (51), a drive shaft torsional angular velocity od is given by the following formula (52). FORMULA 52

[0159] where Hw(s) in formula (52) is provided by the following formula (53). FORMULA 53

[0160] where v1, v0, w1 and w0 in formula (53) are provided by the following formula (54). FORMULA 54

[0161] Formula (54) can be transformed into the following formula (55). FORMULA 55

[0162] In the present document, in formula (55), Çp is a damping coefficient of a drive shaft torque transmission system, and op is a natural vibration frequency of the drive shaft torque transmission system.

[0163] Furthermore, poles and zero points of formula (55) are examined. Since α « 00/01, the following formula (56) is obtained by pole zero cancellation. FORMULA 56

[0164] where gt in formula (56) is provided by the following formula (57). FORMULA 57

[0165] In this document, a final torque command value Tmf* can be provided by the following formula (58). FORMULA 58

[0166] Then, the final torque command value Tmf* can be substituted as given by the following formula (59). FORMULA 59

[0167] Then, formula (59) is replaced by formula (56), since the engine torque Tm = final torque command value Tmf* (Tm=Tmf*), so that formula (56) can be rearranged as given by the following formula (60). FORMULA 60

[0168] A model response of motor torque to drive shaft torque is provided by the following formula (61). FORMULA 61

[0169] When the model response is given by formula (61), a condition under which the transfer characteristic (formula (60)) of the final torque command value Tmf* to the drive shaft torque Td and the model response are correlated to each other is given by the following formula (62). FORMULA 62

[0170] Subsequently, by applying the above formulas (37) to (53), a dead zone that simulates a gear backlash characteristic from the motor to the drive shafts is modeled (dead zone model). Then, the drive shaft torque Td that takes into account the dead zone model can be given by the following formula (63). FORMULA 63

[0171] where θdead is an amount of total gear backlash from the motor to the drive shafts.

[0172] Figure 16 is a control block diagram explaining the vibration damping control computing process performed in step S203. The vibration damping control computing process of this embodiment is carried out using an F/F compensator 1501, an F/B compensator 1502 and an adder 1503.

[0173] Using a target torque command value Tm* as an input, the F/F compensator 1501 calculates a first torque command value Tm1* and an estimated engine rotational angular velocity value oAm for the first torque command value Tm1*.

[0174] The F/B 1502 compensator calculates a second torque command value Tm2* using as inputs the estimated value of engine rotational angular speed oAm, a detected value of engine rotational speed om and a command value of braking/drive force Tmr1*.

[0175] Adder 1503 adds the first torque command value Tm1* and the second torque command value Tm2* to output a final torque command value Tmf*.

[0176] Figure 17 is a control block diagram illustrating details of the F/F compensator 1501 illustrated in Figure 16. The F/F compensator 1501 is composed of an F/B axis torsional angular velocity computing unit. drive 1601 and a vehicle model 1602. Note that the F/F compensator 1501 illustrated herein is the same as an F/F compensator disclosed in international publication No. WO 2013/157315.

[0177] Vehicle model 1602 is comprised of a dead zone model that simulates vehicle parameters (see Figure 15) and gear backlash from engine 4 to drive axles 8 by applying the formulas ( 37) to (48). In vehicle model 1602, the drive shaft torque Td that takes into account a dead zone characteristic (dead zone model) indicated by a dead zone block 1603 is calculated by applying the above formula (63).

[0178] In this document, in a scene such as vehicle acceleration from coasting or deceleration, a dead zone period occurs during which drive motor torque is not transmitted to the drive axles due to the influence of gear backlash. In this regard, by calculating the first torque command value using the 1602 vehicle model in which the dead zone period is considered, the drive motor torque is controlled to be approximately zero in the dead zone period and to increase as the gears mesh. Therefore, in the case where the gears are disengaged due to the influence of gear backlash, it is possible to suppress a shock when the gears mesh again.

[0179] Using the first torque command value as an input, the vehicle model 1602 calculates an estimated drive shaft torsional angular velocity value o'd and the estimated engine rotational angular velocity value o' m.

[0180] Then, the estimated engine rotational angular velocity value output from the vehicle model 1602 is fed into the F/B compensator 1502 (see Figure 16), and the estimated engine rotational angular velocity value o'd drive is input into drive shaft torsional angular velocity F/B computing unit 1601.

[0181] The drive shaft torsional angular velocity F/B computing unit 1601 includes a feedback gain 1604 (F/B gain k1) and a subtractor 1605. The shaft torsional angular velocity F/B computing unit drive shaft 901 calculates the first torque command value using as inputs the target torque command value Tm1* and the estimated drive shaft torsional angular velocity value o'd.

[0182] Using the estimated drive shaft torsional angular velocity value of d as an input, the feedback gain 1604 calculates a value by multiplying the estimated drive shaft torsional angular velocity value of d by a gain F/B k1 which is calculated by applying the above formula (62) based on a damping coefficient Çr1 according to a model response in a period other than the dead zone period, and outputs the calculated value to the subtractor 1605 .

[0183] Then, subtractor 1605 subtracts the feedback gain output value 1604 from the target torque command value to calculate the first torque command value. The first torque command value is issued for vehicle model 1602 and adder 1503 illustrated in Figure 16.

[0184] Figure 18 is a control block diagram illustrating details of the F/B compensator 1502 illustrated in Figure 16. The F/B compensator 1502 is composed of a gain 1701 (K gain), a control block 1702, adders 1703, 1705, a control block 1704, a subtractor 1706 and a control block 1707.

[0185] Gain K is arranged to adjust the safety margin (gain margin, phase margin) of the feedback control system and is set to a value equal to or less than 1.

[0186] Control block 1702 is a filter composed of the transfer characteristic Gp(s) provided by the above formula (44). The 1702 control block calculates an estimated value of the motor rotational angular velocity of m1 using as an input the second torque command value prior to gain adjustment by the filter gain K and using the transfer characteristic GP(s).

[0187] The adder 1703 outputs to the adder 1705 a value obtained by adding together the estimated value of engine rotational angular velocity of m calculated by the vehicle model 1602 included in the F/F compensator 1501 and the estimated value of angular speed of rotation of motor of m1 as the output of control block 1702.

[0188] Control block 1704 is a filter composed of the transfer characteristic Gprf(s) provided by the above formula (26). The control block 1704 calculates an estimated value of the motor rotational angular velocity of m2 using the braking/drive force command value Tmr1* as an input and using the transfer characteristic Gprf(s).

[0189] Then, in adder 1705, the value obtained by adding the estimated value of the engine rotation angular speed ofm and the estimated value of the engine rotation angular speed ofm1 together and the estimated value of the rotation angular speed of motor of m2 are added together. Consequently, the estimated front engine rotational angular velocity value calculated based on the first torque command value is connected based on the braking/drive force command value that indicates a braking/drive torque for the drive wheels rear, thus calculating an estimated value of final engine rotational angular velocity <aAm3.

[0190] The subtractor 1706 sends to the control block 1707 a deviation between an estimated value and a detected value of the engine rotation angular speed obtained by subtracting the engine rotation angular speed o>m from the final estimated speed value engine rotation angle <aAm3.

[0191] Control block 1707 is an Hf(s)/Gp(s) filter composed of an inverse characteristic of the Gp(s) transfer characteristic of the control object and an Hf(s) bandpass filter. The Hf(s) bandpass filter is configured by applying the above formula (34), as in the first embodiment. The control block 1707 calculates the second torque command value using as an input the deviation between the estimated value and the detected value of the engine rotational angular velocity, which is the output of the subtractor 1706, and using of the Hf(s)/Gp(s) filter.

[0192] The transfer characteristic Gprf(s) of the control object used in control block 1704 can be approximated by a filter configured by applying the following formula (64) which considers that the torsional vibration frequencies of the front drive wheels and rears become a cutoff frequency. By approximating such a filter, the computation load can be reduced. Although the following formula (64) considers the torsional vibration frequencies of both the front and rear drive wheels, the transfer characteristic Gprf(s) can be approximated by a filter considering only the torsional vibration frequency of at least one of the wheels of drive. FORMULA 64

[0193] The transfer characteristic Gprf(s) of the control object used in control block 1704 can be approximated by a filter configured by applying the following formula (65) which considers only one characteristic of an element in a steady state ( static characteristic). Consequently, since the estimated engine rotation angular velocity value ®Am2 can be calculated by gain adjustment without using the vehicle model, it is possible to reduce the software computation load of the electric motor controller 2. FORMULA 65

[0194] Furthermore, when there is a characteristic in which the damping coefficient due to the torsional vibration frequency becomes less than 1, the control block 1704 can use, instead of the transfer characteristic Gprf(s), the transfer characteristic Grrf(s) given by the above formula (29) in which the damping coefficient Ç (Ç,pr, Çpf) is approximately 1. That is, when it has a characteristic in which the damping coefficient due to the torsional vibration frequency becomes less than 1, the damping coefficient Ç (Ç,pr, Çpf) can be set to a value equal to or greater than 1. In a transfer function of the engine rotational angular velocity of the front drive motor to the rear drive wheels , when it has a characteristic in which the damping coefficient due to the torsional vibration frequency in a denominator is less than 1, there is a characteristic such that the amount of correction of engine rotational angular velocity (estimated value of rotational angular velocity of m2) becomes oscillatory according to changes in braking/drive force. In this case, it is possible to suppress the oscillatory characteristic of the engine rotational angular velocity correction amount by setting the damping coefficient to a value equal to or greater than 1.

[0195] Furthermore, it has been described that, in the third embodiment, the Gp(s) transfer characteristic used in control block 1702 and control block 1707 is configured based on the 2WD vehicle model provided by the above formula (44) . However, as in the first embodiment, the Gp(s) transfer characteristic can be configured by applying the above formula (12) which is based on the 4WD vehicle model considering the front and rear drive force characteristics. By using the 4WD vehicle model that considers not only the front drive wheels but also the rear drive wheels, the engine rotational angular velocity can be estimated more accurately.

[0196] In the present document, the results of vibration damping control by the control device for an electric vehicle of the third embodiment will be described with reference to Figure 19.

[0197] Figure 19 is a time graph for comparing the control results by the control device for an electric vehicle of the third embodiment and the control results according to the prior art. In the Figure, a final torque command value Tmf*, a braking/drive force command value Tmr1, a second torque command value and a longitudinal acceleration of a vehicle are respectively illustrated in that order from above. In the Figure, solid lines indicate control results according to the third embodiment, and dashed lines indicate control results according to the prior art. Note that, since there is no difference between the prior art and this embodiment, the braking/drive force command value Tm1* is indicated by a dashed line.

[0198] Figure 19 illustrates the control results on a vehicle, which is a 2WD electric motor vehicle, in which a braking/drive force (e.g. braking torque, engine output and the like) is also input to the wheels different from the drive wheels to which an electric motor is connected. Specifically, Figure 19 illustrates the control results when a driver quickly presses an accelerator from a stationary state of the vehicle so that the front target torque command value and the brake/drive force command value for the wheels different drive levels are increased to accelerate the vehicle.

[0199] First, at time t1, the front end torque command value is changed by pressing the accelerator pedal by the driver.

[0200] Then, in the prior art (dashed lines), since front and rear braking/drive forces are not considered, a detected value of a front engine rotational speed becomes greater than that estimated by a control system. feedback control which corresponds to an addition of a drive force via different drive wheels. Then, in order to compensate for a torque that corresponds to a detected motor rotation speed greater than the estimated one, the torque command value is corrected on the negative torque side (in a direction to reduce the motor torque) to prevent acceleration from time t1 to t3 (see second torque command value). Therefore, the front end torque command value Tmf* cannot be output as a torque command value required by the conduit. As a result, it is observed that the longitudinal acceleration of the vehicle is limited around time t2 compared to time t3.

[0201] Thus, in the prior art, since excess vibration compensation is emitted from an F/B compensator to prevent the vehicle from accelerating, it is not possible to achieve a driver's intended acceleration or deceleration based on an accelerator operation or a brake operation by the driver and therefore a feeling of incongruity is provided for the driver.

[0202] In contrast, according to the control device for an electric vehicle of the third embodiment (solid lines), even when the front end torque command value is changed by one step in time t1, the second end torque command value torque is zero from time t1 to t3. Therefore, even with the control device for an electric vehicle of the third embodiment, it is possible to suppress the excess vibration suppression compensation (negative torque) that is emitted from the vibration damping control F/B compensator as in previous technique (dashed lines). Therefore, from time t1 to t3, the front end torque command value Tmf* can be output as a torque command value intended by the driver.

[0203] As a result, even when braking/drive force is generated on different drive wheels, it is possible to obtain an acceleration desired by the driver. This is the effect obtained by correcting the estimated value of the engine rotational angular speed using the filter configured based on the transfer function of the engine rotational angular speed to the drive wheels, according to the command value of braking/drive force for the different drive wheels.

[0204] Although the control results on the drive side of the 2WD electric vehicle have been described, the control results during regenerative operation are the same. That is, in the prior art, when the 2WD electric vehicle is decelerated, the second torque command value is corrected on the positive torque side by excess vibration suppression compensation, so that deceleration is prevented and therefore not it is possible to achieve the deceleration desired by the user. In contrast, according to the control device for an electric vehicle of the third embodiment, such as the control on the drive side described above, since it is possible to suppress the excess vibration suppression compensation output (positive torque) from of the vibration damping control F/B compensator, it is possible to carry out a deceleration desired by the driver.

[0205] As described above, according to the control device for an electric vehicle of the third embodiment, in direct power computation, a drive shaft torsional angular velocity is calculated from the motor torque command value with the use of a dead zone vehicle model (vehicle model 1602) that has a dead zone in which the torque of the first motor (front drive motor) is not transferred to the drive shaft torque, and the first command value of torque is calculated by feedback of the calculated drive shaft torsional angular velocity to the motor torque command value. Consequently, the engine torque is controlled to be approximately zero in the dead zone period and to increase as the gears mesh. As a result, in the case where the gears are disengaged due to the influence of gear backlash, it is possible to suppress a shock when the gears mesh again.

[0206] Furthermore, according to the control device for an electric vehicle of the third embodiment, a filter with the function of transferring the angular speed of rotation from the first motor (front drive motor) to the second drive wheel (front drive wheel) rear drive) is approximated by a filter in which a torsional vibration frequency of at least one of the first drive wheel (front drive wheel) and the second drive wheel is defined as a cutoff frequency. Consequently, it is possible to reduce the software computing load of the electric motor controller 2.

[0207] Furthermore, according to the control device for an electric vehicle of the third embodiment, a filter with the function of transferring the angular speed of rotation from the first motor (front drive motor) to the second drive wheel (front drive wheel) rear drive) is approximated to form a gain component of a transfer characteristic of the angular velocity of rotation of the first motor to the second drive wheel. Consequently, since the estimated value of engine rotation angular velocity ofm2 can be calculated by gain adjustment without using the vehicle model, it is possible to reduce the software computation load of the electric motor controller 2.

[0208] Furthermore, according to the control device for an electric vehicle of the third embodiment, a filter with the function of transferring the angular speed of rotation from the first motor (front drive motor) to the second drive wheel (front drive wheel) rear drive) has, in a denominator, a damping coefficient due to a torsional vibration frequency, and when it has a characteristic in which the damping coefficient becomes less than 1, the damping coefficient is set to a value equal to or greater that 1. Consequently, it is possible to suppress the oscillatory characteristic of the engine rotation angular speed correction amount.

[0209] Furthermore, according to the control device for an electric vehicle of the third embodiment, a 4WD vehicle model that simulates a transfer characteristic of torque inputs to the first drive wheel and the second drive wheel at angular speeds of engine rotation of the first engine and the second engine can be used as the vehicle model Gp(s). By using the vehicle model that considers not only the front drive wheel but also the rear drive wheel, the engine rotational angular velocity can be estimated more accurately.

FOURTH MODE

[0210] It is assumed that a control device for an electric vehicle of this embodiment is applied to the system configuration 2 described above. Hereinafter, the vibration damping control computation process that is performed in step S503 described above by the control device for an electric vehicle of the fourth embodiment will be described with reference to Figures 20 and 21.

[0211] Figure 20 is an example of a block configuration diagram that realizes the vibration damping control computing process of the fourth embodiment. The control blocks illustrated in Figure 20 include an F/F compensator 1801, a control block 1802, a control block 1803, adders 1804, 1805, and subtractors 1806, 1807.

[0212] The F/F compensator 1801 performs an F/F compensation process with the use of a front target torque command value Tm1* and a rear target torque command value Tmr1* as inputs and with the use of a 4WD vehicle model. Accordingly, the F/F compensator 1801 calculates a first torque command value and a second torque command value and additionally calculates an estimated front engine rotational angular velocity value oAmf and an estimated engine rotational angular velocity value rear oAmr. Details of the F/F 1801 compensator will be described with reference to Figure 21.

[0213] Figure 21 is an example of a control block configuration that performs the F/F compensation process carried out in the F/F compensator 1801.

[0214] As illustrated, the F/F compensator 1801 is composed of a 4WD vehicle model 1900, a front drive shaft torsional angular velocity F/B computing unit 1901, and a speed F/B computing unit 1902 rear drive shaft torsional angle.

[0215] The 4WD vehicle model 1900 is configured by adding a front dead zone model 1903 and a rear dead zone model 1904 to the 4WD vehicle model 903 illustrated in Figure 10, which is configured equivalent to the equation of motion (1 ) to (11) of the 4WD vehicle.

[0216] Front dead zone model 1903 is a dead zone model that simulates vehicle parameters (see Figure 7) and a gear backlash characteristic of the front drive motor 2f to the front drive wheel 9f, and is given by the above formula (63).

[0217] The rear dead zone model 1904 is a dead zone model that simulates, like the front dead zone model, vehicle parameters (see Figure 7) and a gear backlash characteristic of the rear drive motor 2r for the front drive wheel 9r, and is given by the following formula (66) applying the above formulas (37) to (53). FORMULA 66

[0218] The 4WD vehicle model 1900 configured in this way takes the first torque command value and the third torque command value as inputs and calculates an estimated front drive shaft torsional angular velocity value, an estimated speed value rear drive shaft torsional angle, the estimated value of the front engine rotational angular velocity oAmf, and the estimated value of the rear engine rotational angular speed fflAmr.

[0219] In the present document, in the illustrated 4WD vehicle model 1900, a drive force Fr for the rear drive wheels calculated based on the third torque command value is added to a system that calculates the estimated value of the angular velocity of front engine speed of mf based on first torque command value. Consequently, in the 4WD vehicle model, the estimated front engine rotational angular velocity value calculated based on the first torque command value can be corrected based on the third rear target torque command value that indicates a braking torque/ drive for the rear drive wheels.

[0220] The front drive shaft torsional angular velocity F/B computing unit 1901 first multiplies the estimated input front drive shaft torsional angular velocity value by a gain k1 which is used to correlate a transfer characteristic of a front end torque command value for a front drive shaft torque and a model response to each other. Then, a value obtained by multiplying the estimated front drive shaft torsional angular velocity value by the gain k1 is subtracted from the front target torque command value Tm1*, thus calculating the first torque command value. The gain k1 is given by the above formula (62).

[0221] The rear drive shaft torsional angular velocity F/B computing unit 1902 first multiplies the estimated input rear drive shaft torsional angular velocity value by a gain k2 which is used to correlate a transfer characteristic of a rear end torque command value for a rear drive shaft torque and a model response to each other. Then, a value obtained by multiplying the estimated rear drive shaft torsional angular velocity value by the gain k2 is subtracted from the front rear torque command value Tmr1*, thus calculating the third torque command value. The gain k2 is given by the following formula (67). FORMULA 67

[0222] Again with reference to Figure 20, the description will be continued. The adder 1806 subtracts a front engine rotational angular velocity «mf from the estimated value of front engine rotational angular velocity ofmf to calculate a deviation between the estimated value and the detected value of the front engine rotational angular velocity ofmf and outputs the value calculated for the 1802 control block.

[0223] The control block 1802 is composed of an Hf(s) bandpass filter provided by the above formula (34) and an inverse characteristic of a Gp(s) vehicle model provided by the above formula (19). The control block 1802 calculates a second torque command value using as an input the deviation between the estimated value and the detected value of the front engine rotational angular velocity and multiplies the deviation by Hf(s)/Gp( s).

[0224] Then, the adder 1804 adds the first torque command value and the second torque command value to calculate a front end torque command value Tmf*.

[0225] Likewise, adder 1807 subtracts a rear engine rotational angular velocity <amr from the estimated value of rear engine rotational angular velocity oAmr to calculate a deviation between the estimated value and the detected value of the engine rotational angular velocity rear and outputs the calculated value to the 1803 control block.

[0226] The control block 1802 is composed of a bandpass filter Hr(s) provided by the above formula (35) and an inverse characteristic of the vehicle model Gp(s) provided by the above formula (19). The control block 1803 calculates a fourth torque command value using as an input the deviation between the estimated value and the detected value of the rear engine rotational angular velocity and multiplies the deviation by Hr(s)/Gp( s).

[0227] Then, the adder 1805 adds the third torque command value and the fourth torque command value to calculate a rear end torque command value Tmrf*.

[0228] In the present document, in a vehicle that has a plurality of drive wheels, when the drive shaft torsional vibration resonance frequencies of the front and rear drive wheels differ from each other, the drive shaft torsional vibration is induced in one of the drive wheels due to the torque disturbance influence of the other drive wheel. However, as described above, with the use of the vehicle model 1900 designed for a plurality of drive wheels and the drive shaft torsional angular velocity F/B computing units 1901, 1902 respectively provided for the plurality of drive wheels , the drive shaft torsional vibration described above can be suppressed. Note that when there is no delay or disturbance of the control system, it is possible to suppress the drive shaft torsional vibration of the front and rear drive wheels only by the F/F 1801 compensator.

[0229] Through the rear end torque command value Tmrf* and the front end torque command value Tmf* calculated as described above, it is also possible to suppress the excess vibration compensation output from an F/B compensator of vibration damping control as indicated by the control results illustrated in Figure 9 described above (see the fourth embodiment in Figure) and therefore it is possible to obtain a driver's intended acceleration even during acceleration with the use of the drive wheels front and rear.

[0230] As described above, according to the control device for an electric vehicle of the fourth embodiment, when the electric vehicle includes a second motor (rear drive motor) as a power source for the second drive wheel (rear drive wheel) rear drive), vehicle model Gp(s) is a 4WD vehicle model that simulates a transfer characteristic of torque inputs to the first drive wheel and the second drive wheel at engine rotational angular speeds of the first engine (front drive motor) and the second motor, and the control device calculates a third torque command value by means of a forward computation based on the motor torque command value, detects an angular speed of rotation of the second motor, calculates a fourth torque command value from a deviation between a detected value and an estimated value of the rotational angular speed of the second motor, and controls the torque of the second motor according to a second torque command value. final torque obtained by adding the third torque command value and the fourth torque command value together. In direct power computation, the control device divides the motor torque command value into a first target torque command value (front target torque command value) for the first drive wheel and a second target torque command value target torque (rear target torque command value) for the second drive wheel, calculates an estimated rotational angular velocity value of the first motor, an estimated rotational angular velocity value of the second motor, an estimated angular velocity value of torsional drive shaft of the first drive wheel, and an estimated torsional drive shaft angular velocity value of the second drive wheel using the first target torque command value and the second target torque command value as inputs and using the 4WD vehicle model 1900, and corrects the estimated rotational angular speed value of the first engine based on the second target torque command value. The control device calculates the first torque command value by subtracting from the first target torque command value a value obtained by multiplying the estimated drive shaft torsional angular velocity value of the first drive wheel by a predetermined gain, and calculates the third torque command value by subtracting from the second target torque command value a value obtained by multiplying the estimated drive shaft torsional angular velocity value of the second drive wheel by a predetermined gain.

[0231] Consequently, it is possible to suppress the vibration suppression compensation output in excess of the vibration damping control F/B compensator, and therefore it is possible to obtain a driver's intended acceleration even during acceleration with the use of the front and rear drive wheels and additionally it is possible to suppress drive shaft torsional vibration of the front and rear drive wheels.

[0232] Although control devices for electric vehicles of embodiments in accordance with the present invention have been described, the present invention is not limited to the embodiments described above, and various modifications and applications are possible. For example, although it has been described that the control device for an electric vehicle of the first embodiment is supposed to be applied to the 4WD vehicle of system configuration 2, the same can also be applied to the vehicle of system configuration 1. In this case, a rear target torque command value Tmr1* (see Figure 6) is handled as a brake/drive force command value that is entered into the F/B compensator 1502 (see Figure 16) and control block 1704 (see Figure 18) of system configuration 1. Consequently, even in the vehicle of system configuration 1, the equivalent effect to that of the vehicle of system configuration 2 can be obtained by calculating an estimated value of engine rotational angular velocity correction from the brake/drive force command value to the rear target torque command value.

[0233] In the description of the embodiments described above, a drive wheel at the front of the vehicle is called a front drive wheel (first drive wheel), and a drive wheel at the rear of the vehicle is called a drive wheel rear (second drive wheel). However, the front and rear of the drive wheels do not necessarily coincide with the front and rear of the vehicle. A drive wheel at the rear of the vehicle may be called a front drive wheel (first drive wheel), and a drive wheel at the front of the vehicle may be called a rear drive wheel (second drive wheel). .

Claims (13)

1. Control method for an electric vehicle, wherein the control method is configured to set a motor torque command value based on vehicle information and to control the torque of a first motor (4f) connected to a first drive wheel (9f), the first drive wheel (9f) being one of a front drive wheel (9f) and a rear drive wheel (9r), the control method comprising: calculating a first command value of torque through a direct feed computation based on the motor torque command value; detect an angular speed of rotation of the first engine (4f); estimate an angular speed of rotation of the first engine (4f) based on the first torque command value using a vehicle model Gp(s) that simulates a transfer characteristic of a torque input to the first drive wheel (9f) for an angular speed of rotation of the first engine (4f); calculate a second torque command value from a deviation between a detected value and an estimated value of the rotational angular speed of the first motor (4f) using an H(s)/Gp(s) filter composed of a inverse characteristic of the vehicle model Gp(s) and a bandpass filter H(s) with a center frequency close to a vehicle torsional vibration frequency; and controlling the torque of the first motor (4f) according to a first final torque command value obtained by adding the first torque command value and the second torque command value together; CHARACTERIZED by correcting, when a braking/drive torque for a second drive wheel (9r), which is the drive wheel different from the first drive wheel (9f), is entered, the estimated value of the rotational angular velocity of the first motor (4f) based on the braking/drive torque for the second drive wheel (9r). 2. Control method for an electric vehicle, according to claim 1, CHARACTERIZED by the fact that: when the braking/drive torque for the second drive wheel (9r), which is the drive wheel different from the first wheel (9f) is entered, a motor rotational angular velocity correction amount is calculated using a transfer function of the rotational angular velocity of the first motor (4f) to the second drive wheel (9r). , the transfer function modeled in advance and which uses the braking/drive torque as an input; and the estimated rotational angular velocity value of the first engine (4f) is corrected based on the engine rotational angular velocity correction amount. 3. Control method for an electric vehicle, according to claim 1, CHARACTERIZED by the fact that when the electric vehicle includes a second motor (4r) as a power source for the second drive wheel (9r), the model Gp(s) vehicle model is a 4WD vehicle model that simulates a transfer characteristic of torque inputs to the first drive wheel (9f) and the second drive wheel (9r), for engine rotational angular speeds of the first motor (4f) and the second motor (4r), and wherein the control method comprises: calculating a third torque command value by means of a forward computation based on the motor torque command value; detect an angular speed of rotation of the second engine (4r); calculate a fourth torque command value from a deviation between a detected value and an estimated value of the rotational angular speed of the second motor (4r) using an H(s)/Gpr(s) filter composed of a inverse characteristic of a vehicle model Gpr(s) that simulates a transfer characteristic from a torque input to the second drive wheel (9r) to an angular speed of engine rotation of the second engine (4r), and a pass filter -H band(s) with a central frequency close to the vehicle's torsional vibration frequency; controlling the torque of the second motor (4r) according to a second final torque command value obtained by adding the third torque command value and the fourth torque command value together; and calculating an estimated rotational angular speed value of the first engine (4f) and an estimated rotational angular speed value of the second engine (4r) using the first torque command value and the third torque command value as inputs and using the 4WD vehicle model, and correct the estimated rotational angular velocity value of the first engine (4f) based on the third torque command value. 4. Control method for an electric vehicle, according to claim 1, CHARACTERIZED by the fact that when the electric vehicle includes a second motor (4r) as a power source for the second drive wheel (9r), the model Gp(s) vehicle model is a 4WD vehicle model that simulates a transfer characteristic of torque inputs to the first drive wheel (9f) and the second drive wheel (9r), for engine rotational angular speeds of the first motor (4f) and the second motor (4r), wherein the control method comprises: calculating a third torque command value by means of a feed-forward computation based on the motor torque command value; detect an angular speed of rotation of the second engine (4r); calculating a fourth torque command value from a deviation between a detected value and an estimated value of the rotational angular speed of the second motor (4r); and controlling the torque of the second motor (4r) according to a second final torque command value obtained by adding the third torque command value and the fourth torque command value together, and wherein the control method comprises in direct power computation: dividing the motor torque command value into a first target torque command value for the first drive wheel (9f) and a second target torque command value for the second drive wheel ( 9r); calculate an estimated rotational angular velocity value of the first motor (4f), an estimated rotational angular velocity value of the second motor (4r), an estimated torsional angular velocity value of the drive shaft of the first drive wheel (9f) , and an estimated drive shaft torsional angular velocity value of the second drive wheel (9r) using the first target torque command value and the second target torque command value as inputs and using the 4WD vehicle, and correct the estimated rotational angular velocity value of the first engine (4f) based on the second target torque command value; calculating the first torque command value by subtracting from the first target torque command value, a value obtained by multiplying the estimated drive shaft torsional angular velocity value of the first drive wheel (9f) by a predetermined gain; and calculating the third torque command value by subtracting from the second target torque command value, a value obtained by multiplying the estimated drive shaft torsional angular velocity value of the second drive wheel (9r) by a predetermined gain . 5. Control method for an electric vehicle according to claim 3 or 4, CHARACTERIZED by the fact that when a drive shaft torsional vibration frequency of the first drive wheel (9f) and a shaft torsional vibration frequency of the second drive wheel (9r) differ from each other, a model response used in feed-forward computation that calculates the first torque command value and a model response used in feed-forward computation that calculates the third value torque command parameters are correlated to each other. 6. Control method for an electric vehicle, according to claim 5, CHARACTERIZED by the fact that: when the torsional vibration frequency of the drive shaft of the second drive wheel (9r) is lower than the torsional vibration frequency of drive shaft of the first drive wheel (9f), the model response used in the feed-forward computation that calculates the first torque command value is correlated to the model response used in the feed-forward computation that calculates the third command value of torque; and when the drive shaft torsional vibration frequency of the first drive wheel (9f) is lower than the drive shaft torsional vibration frequency of the second drive wheel (9r), the model response used in forward feed computation that calculates the third torque command value is correlated to the model response used in the forward power computation that calculates the first torque command value. 7. Control method for an electric vehicle, according to claim 5, CHARACTERIZED by the fact that it comprises: calculating the first torque command value by means of direct power computation using a filter having a characteristic of transfer that dampens the torsional vibration frequency of the drive shaft of the first drive wheel (9f); and calculating the third torque command value through forward power computation using a filter having a transfer characteristic that dampens the drive shaft torsional vibration frequency of the second drive wheel (9r). 8. Control method for an electric vehicle, according to claim 2, CHARACTERIZED by the fact that a filter with the function of transferring the angular speed of rotation of the first motor (4f) to the second drive wheel (9r) is approximated by a filter in which a torsional vibration frequency of at least one of the first drive wheel (9f) and the second drive wheel (9r) is defined as a cutoff frequency. 9. Control method for an electric vehicle, according to claim 2, CHARACTERIZED by the fact that a filter with the function of transferring the angular speed of rotation of the first motor (4f) to the second drive wheel (9r) is approximated to form a gain component of a transfer characteristic of the rotational angular velocity of the first motor (4f) to the second drive wheel (9r). 10. Control method for an electric vehicle, according to claim 2, CHARACTERIZED by the fact that: a filter with the function of transferring the angular speed of rotation of the first motor (4f) to the second drive wheel (9r) has, in one denominator, a damping coefficient due to a torsional vibration frequency; and when it has a characteristic in which the damping coefficient becomes less than 1, the damping coefficient is set to a value equal to or greater than 1. 11. Control method for an electric vehicle according to claim 2, CHARACTERIZED by the fact that, in direct power computation, a drive shaft torsional angular velocity is calculated from the motor torque command value using of a dead zone vehicle model that has a dead zone in which the first motor torque (4f) is not transferred to the drive shaft torque, and the first torque command value is calculated by feedback from the torsional angular velocity of drive shaft calculated for the engine torque command value. 12. Control method for an electric vehicle, according to claim 2, CHARACTERIZED by the fact that the vehicle model Gp(s) is a 4WD vehicle model that simulates a characteristic of transferring torque inputs to the first wheel drive wheel (9f) and the second drive wheel (9r), for engine rotational angular speeds of the first engine (4f) and a second engine (4r) as a power source for the second drive wheel (9r). 13. Control device for an electric vehicle, wherein the control device includes a controller (2fr) configured to set a motor torque command value based on vehicle information and to control the torque of a first motor (4f ) connected to a first drive wheel (9f), the first drive wheel (9f) being one of a front drive wheel (9f) and a rear drive wheel (9r), the controller (2fr) being configured to: calculate a first torque command value by means of a forward computation based on the motor torque command value; detect an angular speed of rotation of the first engine (4f); estimate an angular speed of rotation of the first engine (4f) based on the first torque command value using a vehicle model Gp(s) that simulates a transfer characteristic of a torque input to the first drive wheel (9f) for an angular speed of rotation of the first engine (4f); calculate a second torque command value from a deviation between a detected value and an estimated value of the rotational angular speed of the first motor (4f) using an H(s)/Gp(s) filter composed of a inverse characteristic of the vehicle model Gp(s) and a bandpass filter H(s) with a center frequency close to a vehicle torsional vibration frequency; and controlling the torque of the first motor (4f) according to a first final torque command value obtained by adding the first torque command value and the second torque command value together; CHARACTERIZED by the fact that the controller (2fr) is additionally configured to: correct, when a braking/drive torque for a second drive wheel (9r), which is the drive wheel different from the first drive wheel (9f), The estimated value of the rotational angular speed of the first motor (4f) is entered based on the braking/drive torque for the second drive wheel (9r).