Electric vehicle control method and electric vehicle control device

Abstract

It includes the following processes: a basic torque distribution process for prescribing a basic torque command value for each drive motor based on the total requested driving force for the electric vehicle and the distribution of the driving force for each drive system; a vibration damping process for obtaining a corrected torque command value by correcting the respective basic torque command values to suppress vibrations of the driving force transmission system; and a driving force control process for controlling the driving force generated by each drive motor based on the corrected torque command value. In the vibration damping process, it is respectively determined whether each drive system is in a dead zone. For the drive system in the dead zone, the correction amount for the basic torque command value is adjusted according to the distribution of the driving force.

Description

Technical Field

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

[0002] The following control method is disclosed in WO2017 / 183231A1. That is, in an electric vehicle capable of being driven by torque from an electric motor, vibration of a driving force transmission system generated in the electric vehicle is suppressed in consideration of transmission characteristics of a power transmission mechanism connected between an output shaft of the driving motor and driving wheels. In particular, in this control method, an insensitive section in the driving shaft torque where the driving motor torque is not transmitted to the electric vehicle is estimated, and processing for accelerating the response of the driving shaft torque is performed in this insensitive section, thereby suppressing an impact caused by the influence of backlash of a gear. Summary of the Invention

[0003] On the other hand, the inventors of the present invention have conducted research focusing on the following problem. That is, in the case of an electric vehicle having a plurality of drive systems each having a drive motor and driving different drive wheels, the timing at which the backlash of the gear of each drive system is blocked varies due to differences in the driving force distribution of each drive system, and the length of the insensitive section may fluctuate. Therefore, even if the current electric vehicle control method is applied to an electric vehicle having a plurality of drive systems, the torque response performance of the electric vehicle in the insensitive section may change according to the driving state, causing discomfort to the occupants.

[0004] Therefore, an object of the present invention is to provide an electric vehicle control method and an electric vehicle control device that can reduce discomfort to the occupants caused by fluctuations in the length of the insensitive section of each drive system in an electric vehicle having a plurality of drive motors.

[0005] According to one aspect of the present invention, there is provided an electric vehicle control method for controlling the driving force of each drive system in an electric vehicle equipped with a plurality of drive systems each having a drive motor. The electric vehicle control method includes the following processes: a basic torque distribution process for specifying a basic torque command value for each drive motor based on the total requested driving force for the electric vehicle and the distribution of the driving force for each drive system; a vibration damping process for correcting each basic torque command value to suppress vibration of the driving force transmission system to obtain a corrected torque command value; and a driving force control process for controlling the driving force generated by each drive motor based on the corrected torque command value. Moreover, in the vibration damping process, it is respectively estimated whether each drive system is in an insensitive section, and in the drive system in the insensitive section, the correction amount for the basic torque command value is adjusted according to the driving force distribution. Brief Description of the Drawings

[0006] Figure 1 It is a block diagram showing the main structure of an electric vehicle that executes the electric vehicle control method of each embodiment.

[0007] Figure 2 It is a flowchart showing the processing flow of the electric vehicle control method.

[0008] Figure 3 It is a diagram showing an example of an accelerator opening - torque table.

[0009] Figure 4 It is a block diagram explaining the front - rear torque distribution process.

[0010] Figure 5 It is a block diagram explaining the vibration damping process related to the first embodiment.

[0011] Figure 6 It is a block diagram explaining the F / F compensator of the front drive system related to the first embodiment.

[0012] Figure 7 It is a block diagram explaining the F / F compensator of the rear drive system related to the first embodiment.

[0013] Figure 8 It is a diagram showing the model of the driving force transmission system of an electric vehicle (4WD).

[0014] Figure 9 It is a diagram explaining the torque response characteristics of an electric vehicle.

[0015] Figure 10 It is a diagram showing a driving force distribution ratio - dead zone attenuation coefficient table.

[0016] Figure 11 It shows the relationship between the front drive shaft torsional angular velocity F / B calculation unit and the driving force distribution ratio - dead zone attenuation coefficient table.

[0017] Figure 12 It is a block diagram explaining the F / B compensator of the front drive system related to the first embodiment.

[0018] Figure 13 It is a block diagram explaining the F / B compensator of the rear drive system related to the first embodiment.

[0019] Figure 14 It is a block diagram explaining the vibration damping process related to the second embodiment.

[0020] Figure 15 It is a block diagram explaining the structure of the F / F compensator related to the second embodiment.

[0021] Figure 16 It is a timing chart for explaining the control results of the electric vehicle control method for each embodiment.

[0022] Figure 17 It is a diagram showing a modification example related to the structure of the electric vehicle.

[0023] Figure 18 It is a diagram showing a modification example related to the structure of the electric vehicle.

[0024] Figure 19 It is a diagram showing a modification example related to the structure of the electric vehicle. Detailed Embodiments

[0025] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0026] [First Embodiment]

[0027] Figure 1 It is a block diagram for explaining the main structure of the electric vehicle 100 that executes the electric vehicle control method. In addition, the electric vehicle 100 in this embodiment refers to a vehicle such as an electric vehicle (EV) or a hybrid electric vehicle (HEV) equipped with one or more electric motors (drive motors 4) as a driving power source. In particular, the electric vehicle 100 in this embodiment has: a front drive system S f , which includes a drive motor 4 (front drive motor 4f) that applies a driving force to the front drive wheels 9fR, 9fL; and a rear drive system S r , which includes a drive motor 4 (rear drive motor 4r) that applies a driving force to the rear drive wheels 9rR, 9rL.

[0028] In addition, in order to simplify the description below, for the structural elements of the front drive system S f and the rear drive system S r , for example, as shown by "drive system S f , S r " etc., the reference numerals of both are simultaneously marked for unified description. That is, in the following description, unless otherwise specifically stated, the structural elements of the front drive system S f and the rear drive system S r are common.

[0029] The battery 1 is composed of an in-vehicle secondary battery that can supply (discharge) the drive power for the power operation of each drive motor 4f, 4r and receive (charge) the regenerative power during regenerative operation.

[0030] Vehicle speed V, accelerator opening APO, rotor phases α f , α r, the current flowing through the drive motors 4f and 4r, i.e., the motor current i f , i r Signals such as those representing various vehicle variables, etc., are input to the motor controller 2 as digital signals. The motor controller 2 generates a PWM signal for controlling the drive motors 4f and 4r based on the input signals. Additionally, drive signals for the inverters 3f and 3r are generated according to the generated PWM signal.

[0031] The inverters 3f and 3r convert the DC current supplied from the battery 1 into AC by turning on / off the two switching elements (e.g., power semiconductor elements such as IGBTs, MOS-FETs, etc.) in each phase, allowing the desired current to flow through the drive motors 4f and 4r.

[0032] The drive motors 4f and 4r generate driving force using the AC current supplied from the inverters 3f and 3r, and transmit the driving force to each drive wheel 9fR, 9fL, 9rR, 9rL via a driving force transmission system composed of the speed reducers 5f and 5r and the drive shafts Dsf and Dsr. Additionally, the drive motors 4f and 4r recover the kinetic energy of the regenerative braking force received from the drive wheels 9fR, 9fL, 9rR, 9rL during vehicle travel as electrical energy. In this case, the inverter 3 converts the AC current generated during the regenerative operation of the drive motor 4 into DC current and supplies it to the battery 1. In particular, the front drive motor 4f supplies driving force to the front drive wheels 9fR and 9fL, and the rear drive motor 4r supplies driving force to the rear drive wheels 9rR and 9rL.

[0033] The current sensor 20 detects the motor current i f , i r (especially the front three-phase AC current i uf , i vf , i wf and the rear three-phase AC current i ur , i vr , i wr ). However, the sum of the three-phase AC current i u , i v , i w is 0, so any two-phase current can be detected and the remaining one-phase current can be obtained through calculation.

[0034] The rotation sensor 21, such as a resolver or an encoder, detects the rotor phase α f , α r .

[0035] Figure 2 is a flowchart showing each process of an electric vehicle control method programmed in a manner executed by the motor controller 2. In addition, Figure 2The processes involved in steps S201 to S205 shown are repeatedly executed at a prescribed operation cycle during the startup of the vehicle system.

[0036] In step S201, the motor controller 2 performs input processing. Specifically, the motor controller 2 receives the signals representing various vehicle states as vehicle information. In particular, among the signals representing vehicle states, there are vehicle speed V (km / h), accelerator opening APO (%), rotor phase α f , α r (rad), the rotational speeds of drive motors 4f and 4r, i.e., motor rotational speed N mf , N mr (rpm), motor current i f , i r , and the DC voltage value V dc (V) of the battery 1, etc.

[0037] The vehicle speed V (km / h) is obtained through communication from other controllers such as the instrument panel and the brake controller. In addition, the motor controller 2 can calculate the vehicle speed v (m / s) by multiplying the mechanical angular velocity ω m (e.g., either the front mechanical angular velocity ω mf or the rear mechanical angular velocity ω mr ) of the drive motor 4 by the tire rolling radius r and dividing by the gear ratio of the final gear, and then perform unit conversion by multiplying it by 3600 / 1000, thereby calculating the vehicle speed V (km / h).

[0038] The accelerator opening APO (%) is obtained from an accelerator opening sensor (not shown) or through communication from other controllers such as a vehicle controller (not shown).

[0039] The rotor phase α f , α r (rad) is obtained from the rotation sensor 21. The motor controller 2 differentiates the rotor phase α f , α r to calculate the rotor angular velocity ω ef , ω er (electrical angular velocity) of each drive motor 4f and 4r. In addition, the motor controller 2 divides the rotor angular velocity ω ef , ω er by the number of pole pairs p of the drive motors 4f and 4r to calculate the mechanical angular velocity of the drive motors 4f and 4r, i.e., the motor rotational angular velocity ω mf , ω mr (rad / s). And the motor controller 2 multiplies the motor rotational angular velocity ω mf , ω mr by the unit conversion coefficient (60 / 2π) to calculate the motor rotational speed Nmf , N mr (rpm).

[0040] Motor current i f , i r (A) is obtained from the current sensor 20. In addition, the DC voltage value V dc (V) is detected by a voltage sensor (not shown) provided in the DC power line between the battery 1 and the inverter 3. Further, the power supply voltage value obtained by a battery controller (not shown) can be obtained as the DC voltage value V dc (V).

[0041] In step S202, the motor controller 2 performs basic torque distribution processing. Specifically, the motor controller 2 sets the basic total torque command value T m as the target value of the total requested driving force for the electric vehicle 100 with reference to the accelerator opening - torque table shown in Figure 3 based on the accelerator opening APO, vehicle speed V, and motor rotational speed N m ＊ .

[0042] And, the motor controller 2 performs Figure 4 the front - rear torque distribution processing shown in. Specifically, the motor controller 2 multiplies the basic total torque command value T m ＊ by the front distribution gain K f (0 ≤ K f ≤ 1) to obtain the front basic torque command value T f corresponding to the target value of the driving force distributed to the front drive system S mf ＊ . In addition, the motor controller 2 multiplies the basic total torque command value T m ＊ by the rear distribution gain (1 - K f ) to obtain the rear basic torque command value T r corresponding to the target value of the driving force distributed to the rear drive system S mr ＊ .

[0043] Next, in step S203, the motor controller 2 performs vibration damping processing. Specifically, the motor controller 2 corrects the front basic torque command value T mf ＊ to suppress vibration of the driving force transmission system (such as torsional vibration of the front drive shaft Dsf) to obtain the front final torque command value T mff ＊ . On the other hand, the motor controller 2 corrects the rear basic torque command value T mr ＊Perform vibration compensation calculation to suppress vibration of the driving force transmission system (such as torsional vibration of the rear drive shaft Dsr) and obtain the final rear torque command value T mrf ＊ . In addition, the vibration damping treatment will be described in detail later.

[0044] In step S204, the motor controller 2 performs current command value calculation processing. Specifically, the motor controller 2 based on the respective final torque command values T obtained in step S203 mff ＊ 、T mrf ＊ 、each motor rotational angular velocity ω mf 、ω mr 、and the DC voltage value V dc , refer to a pre-specified table to obtain the d-axis current target values i of the front drive motor 4f and the rear drive motor 4r respectively df ＊ 、i dr ＊ and the q-axis current target values i qf ＊ 、i qr ＊ .

[0045] In step S205, the motor controller 2 performs current control operation processing. Specifically, the motor controller 2 performs operations to make the d-axis current i of the front drive motor 4f df and the q-axis current i qf respectively coincide with the d-axis current target value i df ＊ and the q-axis current target value i qf ＊ , and make the d-axis current i of the rear drive motor 4r dr and the q-axis current i qr respectively coincide with the d-axis current target value i dr ＊ and the q-axis current target value i qr ＊ coincide.

[0046] More specifically, the motor controller 2 respectively based on the d-axis current target values i of the respective drive motors 4f, 4r df ＊ 、i dr ＊ and the q-axis current target values i qf ＊ 、i qr ＊Each PWM signal is generated separately. The switching elements of the front inverter 3f and the rear inverter 3r are opened and closed by using the respective PWM signals thus obtained, and the front drive motor 4f and the rear drive motor 4r can be driven with desired torques respectively.

[0047] Next, the vibration damping process S203 described above will be described in detail.

[0048] Figure 5 is a block diagram for explaining the vibration damping process of the present embodiment. In particular, the vibration damping process S203 of the present embodiment has a structure for performing a process of suppressing vibration of the driving force transmission system of the front drive system S f (the upper diagram in Figure 5 ), and a structure for performing a process of suppressing vibration of the driving force transmission system of the rear drive system S r (the lower diagram in Figure 5 ). In addition, hereinafter, for the sake of simplicity of explanation, the respective structures of the front drive system S f and the rear drive system S r will be collectively described with the above reference numerals for unified explanation.

[0049] As shown in the figure, the vibration damping process S203 includes F / F compensators S501, S503 and F / B compensators S502, S504.

[0050] Figure 6 and Figure 7 is a block diagram for explaining the F / F compensators S501, S503. As shown in the figure, the F / F compensators S501, S503 have vehicle models S601, S701, and torque correction units S602, S702.

[0051] The vehicle models S601, S701 use the first torque command values T mf1 ＊ , T mr1 ＊ obtained by the torque correction units S602, S702 as inputs, and use a dead zone model that simulates the driving force characteristics of the electric vehicle 100 to obtain estimated values ω^ df of the torsional angular velocities of the drive shafts Dsf, Dsr, dr and estimated values θ^ df of the torsional angles, dr . Here, the estimated values ω^ df , ω^ dr are fed back to the torque correction units S602, S702, and act as indicators for a specified vibration suppression correction amount in the torque correction units S602, S702. On the other hand, the estimated values θ^ df , θ^ dr ​​Feedback to the torque correction units S602 and S702 as a determination index indicating whether each drive system S f and S r is in the dead zone and functions accordingly.

[0052] In addition, the dead zone of the drive systems S f and S r refers to the period during which the backlash of the gears is blocked, etc., during which the output torque of the drive motors 4f and 4r (hereinafter also referred to as "motor torque T mf and T mr ") is not transmitted to the drive shafts Dsf and Dsr (hereinafter also referred to as "drive shaft torque T df and T dr "). In particular, the dead zones of the drive systems S f for the front drive system and S r for the rear drive system are specified for each drive system of the drive systems S f and S r . Additionally, the state in which both drive systems S f and S r are in the dead zone (the torque-free response state of the electric vehicle 100) is appropriately referred to as "the dead zone of the electric vehicle 100".

[0053] Moreover, the vehicle models S601 and S701 calculate estimated values of the motor rotational angular velocities ω mf1 ＊ and ω mr1 ＊ based on the first torque command values T mf and ω m (hereinafter also referred to as "estimated motor rotational angular velocity ω^ mf and ω^ mr ") and output them to the F / B compensators S502 and S504.

[0054] The torque correction units S602 and S702 calculate the first torque command values T mf ＊ and T mr ＊ , the estimated torsional angle values θ^ df and θ^ dr , and the estimated torsional angular velocity values ω^ df and ω^ dr as inputs to calculate the first torque command values T mf1 ＊ and T mr1 ＊ . Specifically, the torque correction units S602 and S702 perform operations on the estimated torsional angular velocity values ω^ df、The vibration compensation torque ΔT is obtained by multiplying ω^dr by a specified feedback gain. mf 、ΔT mr is subtracted from the basic torque command value T mf ＊ 、T mr ＊ to calculate the first torque command value T mf 、ΔT mr mf1 ＊ 、T mr1 ＊ df 。

[0055] Specifically, the torque correction units S602 and S702 use the normal gain k df 、k f1 、k r1 or the dead zone gain k f2 、k r2 as the above-mentioned feedback gain to calculate the vibration compensation torque ΔT mf 、ΔT mr 、ΔT df 、θ^dr is not zero (it is presumed that the drive system S f 、S r is in the normal range except for the dead zone), the torque correction units S602 and S702 multiply the estimated angular velocity of torsion ω^ df 、ω^dr by the normal gain k f1 、k r1 to obtain the vibration compensation torque ΔT mf 、ΔT mr 。 On the other hand, when the estimated torsion angle θ^ df 、θ^dr is zero (it is presumed that the drive system S f 、S r is in the dead zone), the torque correction units S602 and S702 multiply the estimated angular velocity of torsion ω^ df 、ω^dr by the dead zone gain k f2 、k r2 to obtain the vibration compensation torque ΔT mf 、ΔT mr 。

[0056] The vehicle models S601 and S701 shown in Figure 6 and Figure 7 will be described in detail.

[0057] Figure 8This is a diagram showing a model of the drive force transmission system of the electric vehicle 100. In addition, the definitions of the respective parameters are shown below, including the parameters that have already been described.

[0058] J mf 、J mr : Motor inertia

[0059] J wf 、J wr : Drive wheel inertia (one axle)

[0060] K df 、K dr : Torsional rigidity of the drive shaft

[0061] K tf 、K tr : Coefficient related to the friction between the tire and the road surface

[0062] N f 、N r : Total gear ratio

[0063] r f 、r r : Tire load radius

[0064] ω mf 、ω mr : Motor rotational angular velocity

[0065] ω^ mf 、ω^ mr : Estimated value of the motor rotational angular velocity

[0066] θ mf 、θ mr : Motor rotational angle

[0067] ω wf 、ω wr : Drive wheel angular velocity

[0068] θ wf 、θ wr : Drive wheel angle

[0069] T mf 、T mr : Motor torque

[0070] T df 、T dr : Drive shaft torque

[0071] F f 、F r : Driving force (two axles)

[0072] θ df 、θ dr : Torsional angle of the drive shaft

[0073] ω df 、ω dr : The torsional angular velocity of the drive shaft

[0074] V: Vehicle body speed

[0075] M: Vehicle body weight

[0076] According to Figure 8 , the equations of motion of the 4WD electric vehicle 100 are represented by the following equations (1) to (11).

[0077] [Mathematical formula 1]

[0078]

[0079] [Mathematical formula 2]

[0080]

[0081] [Mathematical formula 3]

[0082]

[0083] [Mathematical formula 4]

[0084]

[0085] [Mathematical formula 5]

[0086]

[0087] [Mathematical formula 6]

[0088] T df = K df ·θ df ...(6)

[0089] [Mathematical formula 7]

[0090] T dr = K dr ·θ dr ...(7)

[0091] [Mathematical formula 8]

[0092] F f = K tf ·(r f ω mf -V)...(8)

[0093] [Mathematical formula 9]

[0094] F r = K tr ·(r r ωmr -V)...(9)

[0095] [Mathematical formula 10]

[0096] θ df = θ mf / N f -θ wf ...(10)

[0097] [Mathematical formula 11]

[0098] θ dr = θ mr / N r -θ wr ...(11)

[0099] The transfer characteristics of the front motor torque T mf to the front motor rotational angular velocity ω mf are represented by the following equations (12) and (13) after performing the Laplace transform on the above equations (1) to (11).

[0100] [Mathematical formula 12]

[0101] ω mf = G p (s)·T mf ...(12)

[0102] [Mathematical formula 13]

[0103]

[0104] Among them, a3, a2, a1, a0, b3, b2, b1, b0 in Equation (13) are respectively represented by the following Equation (14).

[0105] [Mathematical formula 14]

[0106]

[0107] In addition, the transfer characteristics of the front motor torque T mf to the front drive shaft torque T df are represented by the following Equation (15).

[0108] [Mathematical formula 15]

[0109]

[0110] Among them, c1, c2 in Equation (15) are represented by the following Equation (16).

[0111] [Mathematical formula 16]

[0112]

[0113] The rotational angular velocity ω of the front motor is represented by the following formula (17) according to formulas (3), (6), (8), and (10). mf to the angular velocity ω of the front drive wheel wf transmission characteristics.

[0114] [Mathematical formula 17]

[0115]

[0116] The torque T of the front motor is represented by the following formula (18) according to formulas (12), (13), and (17). mf to the angular velocity ω of the front drive wheel wf transmission characteristics.

[0117] [Mathematical formula 18]

[0118]

[0119] The torque T of the front drive shaft is represented by the following formula (19) according to formulas (15) and (18). df to the angular velocity ω of the front drive wheel wf transmission characteristics.

[0120] [Mathematical formula 19]

[0121]

[0122] Here, if formula (1) is transformed, the following formula (20) is obtained.

[0123] [Mathematical formula 20]

[0124]

[0125] Therefore, the torsional angular velocity ω of the front drive shaft Dsf can be represented by the following formula (21) according to formulas (19) and (20). df .

[0126] [Mathematical formula 21]

[0127]

[0128] Among them, H wf (s) in formula (21) is defined by the following formula (22).

[0129] [Mathematical formula 22]

[0130]

[0131] In addition, v1, v0, w1, and w0 in formula (22) are defined by the following formula (23).

[0132] [Mathematical formula 23]

[0133]

[0134]

[0135] In addition, Equation (15) can be transformed as shown in Equation (24) below.

[0136] [Mathematical formula 24]

[0137]

[0138] Here, "ζ" in Equation (24) p is the attenuation coefficient of the torque transmission system of the front drive shaft Dsf, and "ω" p is the natural vibration frequency of the torque transmission system of the front drive shaft Dsf.

[0139] Moreover, the extreme point α and the zero point c0 / c1 of the transfer function represented by Equation (24) can be regarded as being approximately the same. Therefore, if extreme-zero cancellation is performed, the following Equation (25) is obtained.

[0140] [Mathematical formula 25]

[0141]

[0142] Among them, g in Equation (25) tf is defined by the following Equation (26).

[0143] [Mathematical formula 26]

[0144] g tf = c0 / a3·α)…(26)

[0145] Here, according to Figure 6 shown in the control logic of the torque correction unit S602 of the front drive system S f , the first torque command value T mf1 ＊ is equal to the front final torque command value T mff ＊ . Thus, using the front basic torque command value T mf ＊ and the usual gain k f1 , the front final torque command value T mff ＊ is represented by the following Equation (27).

[0146] [Mathematical formula 27]

[0147] T mff * = T mf *-k f1 ω df …(27)

[0148] Thus, the previous final torque command value T mff ＊ can be replaced as shown in the following equation (28) using equations (6) and (10).

[0149] [Mathematical formula 28]

[0150] T mff * = T mf * -(k f1 s)T df / K df …(28)

[0151] Moreover, if equation (28) is substituted into equation (24) with T mf = T mff ＊ it can be arranged as shown in the following equation (29).

[0152] [Mathematical formula 29]

[0153]

[0154] Here, the normalized response of the previous motor torque to the previous drive shaft torque T df is represented by the following equation (30).

[0155] [Mathematical formula 30]

[0156]

[0157] The condition for equations (29) and (30) to be consistent is usually represented by the gain k f1 as shown in the following equation (31).

[0158] [Mathematical formula 31]

[0159] k f1 = 2(1 - ζ p )ω p K df / g tf …(31)

[0160] That is, from the perspective of realizing the normalized response in the normal range where the previous motor torque T mf is transmitted as the previous drive shaft torque T df the normal gain k f1 is specified.

[0161] In addition, the dead zone gain k f2 is specified by the following equation (32).

[0162] [Mathematical formula 32]

[0163] k f2 = 2(ζ γf - ζ p )ω p K df / g tf …(32)

[0164] In addition, "ζ" in Equation (32) γf represents the decay coefficient of the canonical response in the dead zone of the front drive system S f (hereinafter also referred to as "the front dead zone decay coefficient ζ γf ").

[0165] That is, from the perspective of achieving a canonical response in the dead zone where the front motor torque T mf is not fully transmitted as the front drive shaft torque T df , the front dead zone is specified by the gain k f2 . In particular, according to Equations (31) and (32), if the front dead zone decay coefficient ζ γf is reduced with respect to the decay coefficient of the canonical response in the normal range ("1" in this embodiment), then the gain k f2 of the dead zone is less than the normal gain k f1 . As a result, when the front drive system S f is in the dead zone, the vibration compensation torque ΔT df specified by the product of the front torsional angular velocity ω f2 and the gain k mf (that is, the reduction correction amount with respect to the front basic torque command value T mf ＊ ) is reduced, so the torque response is further advanced compared to the normal range.

[0166] Moreover, in this embodiment, Equations (1) to (23) are applied to construct a dead zone model that simulates the backlash characteristics of the front drive system S f . The front drive shaft torque T df considering the dead zone model is represented by the following Equation (33).

[0167] [Mathematical formula 33]

[0168]

[0169] Here, "θ" in Equation (33) deadf represents the total backlash amount of the gears from the front drive motor 4f to the front drive shaft Dsf.

[0170] In addition, regarding the rear drive system S r the normal gain k r1 and the dead zone gain k r2 can also be obtained by the same arithmetic logic as that of the front drive system S f for the normal gain k f1 and the dead zone gain k f2 and according to the following formulas (34) and (35).

[0171] [Equation 34]

[0172] k r1 = 2(1 - ζ pr )ω pr K dr / g tr …(34)

[0173] [Equation 35]

[0174] k r2 = 2(ζ γr - ζ pr )ω pr K dr / g tr …(35)

[0175] In addition, "ζ γr " in Equation (35) represents the attenuation coefficient of the normalized response of the dead zone at the rear (hereinafter also referred to as "rear dead zone attenuation coefficient ζ γr ").

[0176] Moreover, considering the rear drive shaft torque T r of the dead zone model that simulates the backlash characteristics of the rear drive system S dr it can also be expressed by the following formula (36) through the same arithmetic logic as that of the front drive system S f .

[0177] [Equation 36]

[0178]

[0179] In addition, the dead zone models of the front drive system S f and the rear drive system S r shown in the above formulas (33) and (36) are respectively implemented by the dead zone module B Figure 6 shown in df and the dead zone module B Figure 7 shown in dr .

[0180] Next, for the dead zone gains k f2 and kr2 The specific regulation method will be described.

[0181] In the present embodiment, in the case where all the driving forces are distributed, the drive system S with earlier torque response of the electric vehicle 100 f 、S r is used as a reference, and the dead zone varying according to the distribution of the driving force is specified by the gain k f2 、k r2 . A more specific description will be given.

[0182] Figure 9 FIG. is a diagram for explaining the torque response characteristics of the electric vehicle 100 according to the present embodiment. In particular, in Figure 9 , the solid line indicates the change with time of each parameter when the front distribution gain K f is set to 1 (when all the driving forces are distributed to the front drive system S f ), and the dashed line indicates the change with time of each parameter when the front distribution gain K f is set to 0 (when all the driving forces are distributed to the rear drive system S r ). In particular, in Figure 9 (A), the basic total torque command value T m ＊ is shown, in Figure 9 (B), the front final torque command value T mff ＊ is shown, in Figure 9 (C), the rear final torque command value T mrf ＊ is shown, and in Figure 9 (D), the front and rear accelerations G of the electric vehicle 100 are shown.

[0183] First, in the case where all the driving forces are distributed to the front drive system S f and the vehicle changes from a decelerating state (front and rear acceleration G < 0) to an accelerating state (front and rear acceleration G > 0), the front drive system S f enters the dead zone at time t1, and a torque response is generated when it exits the dead zone at time t2 thereafter. On the other hand, in the same case where all the driving forces are distributed to the rear drive system S r , it enters the dead zone at the same time t1, but a torque response is generated at time t3 after time t2. That is, the residence time (t2 - t1) of the dead zone of the front drive system S f when all the driving forces are distributed to it (K f = 1) is shorter than that of the rear drive system S f , and in the case of the rear drive system S rIn the case where all driving forces are allocated (K f = 0), the dwell time (t3 - t1) of the dead zone of the rear drive system S r is short. This can be said to be due to the mechanical characteristics of the front drive system S f and the rear drive system S r respectively. Therefore, in this case, the front drive system S f with a further advanced torque response in the dead zone when all driving forces are allocated is used as a reference to define the dead zone gain k f2 、k r2 .

[0184] Next, the method of defining the dead zone gain k f2 、k r2 will be described in detail.

[0185] Figure 10 Represents the driving force distribution ratio - dead zone attenuation coefficient table. In addition,[[]] Figure 11 Represents the relationship between the front torque correction unit S602 and the driving force distribution ratio - dead zone attenuation coefficient table.

[0186] As Figure 10 shown, the front dead zone attenuation coefficient ζ shown by the dashed line γf When all driving forces are allocated to the front drive system S f (K f = 1), it is set to 1, which is the same as the attenuation coefficient of the standard response in the normal range (hereinafter, also simply referred to as "reference attenuation coefficient"). Therefore, according to Figure 11 the formula (32) shown, the front dead zone gain k f2 is the same as the front normal gain k f1 (formula (31)). That is, in this case, it becomes a state where the electric vehicle 100 is driven by the front drive system S f alone with a further advanced torque response. Therefore, it is possible to ensure the same torque response performance as in the case where only the front drive system S f is mounted on the electric vehicle 100.

[0187] In addition, driving forces are allocated to both the front drive system S f and the rear drive system S r , but in the region where the driving force allocated to the front drive system S f is relatively large (0.5 < K f < 1), the front dead zone attenuation coefficient ζ γf uses the above reference attenuation coefficient as a base point so that even if the front allocation gain K f is reduced, it can maintain the state when all driving forces are allocated (K f= 1) in a manner of torque response performance, set to be reduced correspondingly with the reduction of the front distribution gain K f On the other hand, for the rear drive system S r the rear dead zone attenuation coefficient ζ γr is maintained as the reference attenuation coefficient. Thus, it is possible to suppress the fluctuation of the torque response characteristics caused by the change in the driving force distribution of the front drive system S f and further improve the torque response performance of the electric vehicle 100.

[0188] Moreover, in a region where the driving force allocated to the rear drive system S f is larger than that of the front drive system S r (0 < K f < 0.5), the front dead zone attenuation coefficient ζ γf is maintained as the reference attenuation coefficient. On the other hand, the rear dead zone attenuation coefficient ζ γr is based on the case where all the driving force is allocated when the torque response in the rear drive system S r is the earliest (K f = 0), and is set to be reduced correspondingly with the increase of the front distribution gain K f < 1 in the same decreasing curve as the gain k f2 of the front dead zone in the region of 0.5 < K f < 1 (the reduction of the driving force allocated to the rear drive system S r ). That is, in this case, the torque response performance of the rear drive system S r does not depend on the driving force distribution and is maintained close to the state when all the driving force is allocated (K f = 0). Thus, it is possible to suppress the fluctuation of the torque response characteristics caused by the change in the driving force distribution of the rear drive system S r and further improve the torque response performance of the electric vehicle 100.

[0189] In addition, regarding the above description, when the torque response in the dead zone of the rear drive system S r is higher than that of the front drive system S f in the case of allocating all the driving force, it can also be applied in the same way as the case of specifying the gain k r for the dead zone with the rear drive system S f2 as the reference. r2 As described above, in this embodiment, the gain k

[0190] for the dead zone of the drive system S f 、S r to which a larger driving force is allocated is set smaller than the normal gain k f2 、k r2 、k r1 、kr1 Therefore, the drive system S to which a larger driving force is allocated f 、S r has a reduced vibration compensation torque ΔT m (= k f × ω d ), and the torque response performance (the followability of the actual driving force with respect to the total requested driving force) of the electric vehicle 100 in the dead zone is improved. In addition, taking the front drive system S that exhibits an earlier torque response when all the driving force is allocated f as a reference, the gains k f2 、k r2 for the dead zone are specified. Therefore, regardless of the differences in the mechanical characteristics of the respective drive systems S f 、S r , the torque response characteristics of the electric vehicle 100 in the dead zone can be made to approach the characteristics in the case where only the front drive system S f with the highest torque response characteristics is used as the drive source.

[0191] Next, the F / B compensators S502 and S504 will be described in detail.

[0192] Figure 12 And Figure 13 are block diagrams showing the structures of the F / B compensators S502 and S504. In particular, Figure 12 shows the structure of the front F / B compensator S502, Figure 13 shows the structure of the rear F / B compensator S504.

[0193] As shown in the figure, the F / B compensators S502 and S504 have gain sections S5021 and S5041, filter sections S5022 and S5042, and filter sections S5023 and S5043.

[0194] The gain K used in the gain sections S5021 and S5041 is arranged to adjust the stability margin (gain margin, phase margin) of the feedback control system and is set to a value less than or equal to 1.

[0195] The filter sections S5022 and S5042 are filters constituted by a transfer characteristic Gp(s) that simulates the transfer characteristic from the motor torque T mf 、T mr to the motor rotational angular velocity ω mf 、ω mr . In addition, the transfer characteristic Gp(s) is specified by, for example, the above equation (13).

[0196] The filtering units S5023 and S5043 are filters such as H(s) / Gp(s) composed of the inverse system of the transfer characteristic Gp(s) and the band-pass filter H(s). The band-pass filter H(s) is set such that the attenuation characteristics on the low-pass side and the high-pass side are substantially the same, and the torsional resonance frequency f of the drive system p is near the central part of the passband on a logarithmic axis (log scale).

[0197] For example, in the case where the band-pass filter H(s) is composed of a first-order high-pass filter and a first-order low-pass filter, the band-pass filter H(s) is configured as shown in the following equation (37).

[0198] [Equation 37]

[0199]

[0200] where τ L = 1 / (2πf HC ), f HC = k·f p , τ H = 1 / (2πf LC ), f LC = f p / k. In addition, the frequency f p is the torsional resonance frequency of the drive systems S f , S r , and k is set to any value that constitutes the band-pass.

[0201] Accordingly, the F / B compensators S502 and S504 add the estimated motor rotational angular velocity values ω^ mf1 ＊ , ω^ mr1 ＊ calculated based on the first torque command values T mf , ω^ mr and the estimated motor rotational angular velocity values ω^ mf2 ＊ , T mr2 ＊ input to the transfer characteristic Gp(s) before multiplying by the gain K, and calculate the final estimated motor rotational angular velocity values ω^ mf1 , ω^ mr1 . And the F / B compensators S502 and S504 calculate the final estimated motor rotational angular velocity values ω^ mff , ω^ mrf . And the F / B compensators S502 and S504 calculate the final estimated motor rotational angular velocity values ω^ mff , ω^ mrf , and the detected motor rotational angular velocity value ω obtained using the rotation sensor 21mf_d , ω mr_d The deviation of is applied with a filter H(s) / Gp(s) and multiplied by a gain K to obtain the second torque command value T mf2 ＊ , T mr2 ＊ .

[0202] Moreover, as Figure 5 shown, in the vibration damping process S203, the final torque command value T mff ＊ , T mrf ＊ is used as the first torque command value T mf1 ＊ , T mr1 ＊ output from the F / F compensators S501 and S503, and the second torque command value T mf2 ＊ , T mr2 ＊ output from the F / B compensators S502 and S504, and is calculated as the sum.

[0203] By calculating the final torque command value T mff ＊ , T mrf ＊ , for the first torque command value T mf1 ＊ , T mr1 ＊ after vibration compensation (feedforward compensation) based on the F / F compensators S501 and S503, the final torque command value T mff ＊ , T mrf ＊ is further specified through vibration compensation (feedback compensation) based on the F / B compensators S502 and S504. As a result, the vibration of the driving force transmission system of each drive system S f , S r can be more reliably suppressed.

[0204] The structures of the present embodiment described above and the functions and effects achieved thereby will be described in a unified manner.

[0205] In the present embodiment, there is provided an electric vehicle control method for controlling the driving forces of drive systems S f , S r in an electric vehicle 100 equipped with a plurality of drive systems S f , S r each having a drive motor 4f and 4r.

[0206] The electric vehicle control method includes: based on the total requested driving force (basic total torque command value T m ＊ ) and for each drive system S f , S r The driving force of allocation (K f or 1-K f ) and specifies the basic torque command value T for each drive motor 4f, 4r. mf ＊ , T mr ＊ The basic torque distribution processing S202: respectively for each basic torque command value T mf ＊ , T mr ＊ A correction torque command value (first torque command value T mf1 ＊ , T mr1 ＊ Or the final torque command value T mff ＊ , T mrf ＊ ) vibration reduction processing S203; and based on the correction torque command value (more specifically, based on the final torque command value T mff ＊ , T mrf ＊ ) and controls the driving force (motor torque T mf , T mr )'s driving force control processing (S204, S205).

[0207] Then, in the vibration reduction process S203, each drive system S is estimated. f , S r Is it in the insensitive range? In the insensitive range, the drive system S f , S r In the above example, the basic torque command value T is adjusted according to the distribution of the driving force. mf ＊ , T mr ＊ The correction amount (vibration compensation torque ΔT mf , ΔT mr ) (refer to Figure 11 ).

[0208] Thus, each basic torque command value T can be adjusted in consideration of the fluctuation of the torque response characteristic in the dead zone caused by the difference in the driving force distribution. mf ＊, T mr ＊ Execute vibration compensation and specify the final torque command value T mff ＊ , T mrf ＊ . Therefore, in the electric vehicle 100 equipped with multiple drive systems S f , S r , a control structure that maintains the vibration damping function and reduces the discomfort of the occupants is achieved.

[0209] Specifically, in the vibration damping process S203, the estimated torsional angular velocity ω^ f , S r of the drive shafts Dsf and Dsr of each drive system S is multiplied by a specified feedback gain (k df , k f1 , k f2 , k r1 , k r2 ) to calculate the vibration compensation torque ΔT mf , ΔT mr . The vibration compensation torque ΔT mf ＊ , T mr ＊ is subtracted from the basic torque command value T mf , ΔT mr to obtain the corrected torque command value (the first torque command value T mf1 ＊ , T mr1 ＊ ) (torque correction units S602, S702). Moreover, the feedback gain in the normal range is set to the normal gain k f1 , k r1 that is constant with respect to the change in the driving force distribution, and the feedback gain in the dead zone is set to the dead zone gain k f2 , k r2 corresponding to the distribution of the driving force.

[0210] Thus, a specific control logic for adjusting the torque response characteristics in the dead zone is achieved for each drive system S f , S r .

[0211] Furthermore, in the vibration damping process S203 of the present embodiment, the dead zone gain k f , S r is specified in such a way that the timing for the drive systems S f2 , k r2 to exit the dead zone is substantially constant regardless of the driving force distribution.

[0212] Accordingly, it is possible to shorten the time of stagnation in the dead zone (any driving system S f 、S r during which the actual output driving force of the electric vehicle 100 is not facilitated), and improve the torque response performance of the electric vehicle 100.

[0213] In addition, in the vibration damping process S203 (particularly the F / F compensators S501, S503), the vehicle models S601, S701 that model the driving force transmission system of the electric vehicle 100 are used to calculate the estimated torsional angular velocity values ω^ f 、S r of the drive shafts Dsf, Dsr of each driving system S df 、ω^dr.

[0214] Accordingly, even when the vibration damping process is applied to the electric vehicle 100 having a plurality of driving systems S f 、S r , it is possible to specify the vibration compensation torques ΔT df 、ω^dr for realizing an optimal vibration suppression function in each driving system S f 、S r through feedforward operation based on the estimated torsional angular velocity values ω^ mf 、ΔT mr specified according to the model corresponding to the actual electric vehicle 100. And, in the present embodiment, in the F / B compensators S502, S504, the feedback vibration compensation torques (the second torque command values T df 、ω^dr and the detected motor rotational angular velocity values ω mf d 、ω mr d are made to coincide respectively through feedback control, so that even in the structure where the vibration damping process is performed for a plurality of driving systems S mf2 ＊ 、T mr2 ＊ 、S f 、S r , it is possible to appropriately remove the redundant vibration suppression compensation amount from the respective torque command values (the first torque command values T mf1 ＊ 、T mr1 ＊ ) after feedforward compensation by the F / F compensators S501, S503, and ensure the accuracy of vibration compensation.

[0215] In addition, in the vibration damping process S203 (especially the F / F compensators S501 and S503), the above vehicle models S601 and S701 are further used to obtain the estimated torsional angle values θ^ f 、S r of the drive shafts Dsf and Dsr of each drive system S df 、θ^dr.

[0216] Thus, the same vehicle models S601 and S701 can be used simultaneously to define the estimated torsional angular velocity values ω^ mf 、ΔT mr for the operation of the vibration compensation torques ΔT df 、ω^dr and the estimated torsional angle values θ^ df 、θ^dr for the estimation of the dead zone. That is, the same vehicle models S601 and S701 can be used to define the respective parameters for the operation of the vibration compensation torques ΔT mf 、ΔT mr and the estimation of the dead zone, so that the control logic can be simplified and the operation load can be reduced.

[0217] Moreover, in the present embodiment, the dead zone gains k f 、S r of the drive systems S f 、S r in which a relatively large driving force is allocated within each drive system S f2 、k r2 are set to be smaller than the normal gains k f 、S r set when the drive systems S f1 、k r1 are in intervals other than the dead zone.

[0218] Thus, the residence time of the dead zone of the drive systems S f 、S r in which a relatively large driving force is allocated is further shortened, so that the torque response of the electric vehicle 100 can be further advanced. In particular, even when other drive systems are in the dead zone, the drive systems S f 、S r with a relatively large allocated driving force can quickly exit the dead zone and output a driving force closer to the total requested driving force of the electric vehicle 100. That is, in this case, the drive systems S f 、S r with a relatively large allocated driving force can obtain the same characteristics as when the electric vehicle 100 is driven alone.

[0219] In addition, in the present embodiment, a drive system (e.g., the front drive system S) which has the characteristic of the shortest dead zone when all the driving forces are distributed is used to f set the dead zone gain k of the drive system S f2 to be less than the normal gain k f set when the drive system S is in a section other than the dead zone, f1 and in this way, the dead zone gains k f 、S r of each drive system S f2 、k r2 are set.

[0220] Thereby, it is possible to make the torque response timing of the electric vehicle 100 in the dead zone coincide with the backlash timing of the front drive system S with a shorter dead zone in terms of mechanical characteristics. That is, the torque response of the electric vehicle 100 can be further advanced. f

[0221] In addition, in the present embodiment, on the basis of the above electric vehicle control method, a motor controller 2 that functions as an electric vehicle control device for executing this method is provided. In particular, the motor controller 2 has: a basic torque distribution unit (S202) that specifies the basic torque command values T m ＊ for each drive motor 4f, 4r based on the total requested driving force (basic total torque command value T f 、S r ) for the electric vehicle 100 and the driving forces (K f or 1 - K f ) distributed to each drive system S mf ＊ 、T mr ＊ ; a vibration damping unit (S203) that performs correction for suppressing vibration of the driving force transmission system on each basic torque command value T mf ＊ 、T mr ＊ to obtain corrected torque command values (first torque command values T mf1 ＊ 、T mr1 ＊ or final torque command values T mff ＊ 、T mrf ＊ ); and a driving force control unit (S204, S205) that, based on the corrected torque command values (more specifically, based on the final torque command values T mff ＊ 、T mrf＊ ), controls the driving forces (motor torques T mf , T mr ) generated by the respective drive motors 4f, 4r. Moreover, the vibration damping unit (S203) respectively estimates whether each drive system S f , S r is in the dead zone, and in the drive systems S f , S r that are in the dead zone, adjusts the correction amounts (vibration compensation torques ΔT mf ＊ , ΔT mr ＊ ) for the basic torque command values T mf , T mr ) according to the distribution of the driving forces (see Figure 11 ).

[0222] [Second Embodiment]

[0223] Next, the second embodiment will be described. In addition, the same elements as those in the first embodiment are denoted by the same reference numerals and their description is omitted.

[0224] Figure 14 is a block diagram for explaining the vibration damping process S203 of the present embodiment. In particular, in the present embodiment, the F / F compensators S1201 are used instead of the F / F compensators S501, S503 of the first embodiment.

[0225] Figure 15 is a block diagram for explaining the structure of the F / F compensator S1201. As shown in the figure, the F / F compensator S1201 has: a vehicle model S1301 composed of dead zone models respectively simulating the driving force characteristics of the front drive system S f and the rear drive system S r ; a front torque correction unit S1302 that obtains the front first torque command value T mf ＊ based on the front basic torque command value T df and the estimated front torsional angular velocity ω^ mf1 ＊ ; and a rear torque correction unit S1303 that obtains the rear first torque command value T mr ＊ based on the rear basic torque command value T mr1 ＊ and the estimated rear torsional angular velocity ω^dr.

[0226] In addition, regarding the normal gain k f and the dead zone gain k f1 of the front drive system S f2, can be defined by Formula (31) and Formula (32) respectively in the same manner as in the first embodiment. Additionally, regarding the rear drive system S r of the normal gain k r1 and the dead zone gain k r2 , can also be defined by Formula (34) and Formula (35) respectively in the same manner as in the first embodiment.

[0227] Moreover, regarding the backlash characteristics of the gears from the drive motors 4f and 4r to the drive shafts Dsf and Dsr of each drive system S f 、S r , can also be defined by Formula (33) and (36) respectively in the same manner as in the first embodiment.

[0228] Returning to Figure 14 , the vibration damping process S203 has F / B compensators S1202 and S1203 instead of the F / B compensators S502 and S504 in the first embodiment.

[0229] Here, the F / B compensator S1202 subtracts the front motor rotational angular velocity detected value ω mf from the front motor rotational angular velocity estimated value ω^ mf_d , and multiplies by the inverse models of the band-pass filter H f (s) and the front vehicle model G pf (s), thereby obtaining the second front torque command value T mf2 ＊ . And the F / B compensator S1202 adds the second front torque command value T mf1 ＊ to the front first torque command value T mf2 ＊ to obtain the front final torque command value T mff ＊ .

[0230] On the other hand, the F / B compensator S1203 subtracts the rear motor rotational angular velocity detected value ω mr from the rear motor rotational angular velocity estimated value ω^ mr_d , and multiplies by the inverse models of the band-pass filter H r (s) and the vehicle model G pr (s), thereby obtaining the second rear torque command value T mr2 ＊ . And the F / B compensator S1203 adds the second rear torque command value T mr1 ＊ to the rear first torque command value T mr2 ＊ to obtain the rear final torque command value T mrf ＊ .

[0231] By means of the electric vehicle control method according to this embodiment, the same effects as those of the first embodiment can also be achieved.

[0232] [Control results of this embodiment]

[0233] Figure 16 It is a comparison chart of the control results of the first embodiment and the second embodiment (examples) and the control results of the reference example. In the figure, the basic total torque command value T is shown in order from the top m ＊ , the front final torque command value T mff ＊ , the rear final torque command value T mrf ＊ , and the front and rear accelerations G. In addition, the solid line, the dotted line, and the dashed-dotted line in each figure respectively represent the control results when the front distribution gain K f is 0.5, 0.7, and 1.0.

[0234] In addition, in Figure 16 , it shows the control results in the case where the basic total torque command value T m ＊ increases with a gentle slope from the state where the vehicle decelerates due to the regenerative torque and accelerates. In addition, in the reference example, the mechanical characteristics of the front and rear drive systems are made different, and feedback gains for prescribing the vibration compensation torques ΔT mf , ΔT mr are set without depending on the distribution of the driving force. On the other hand, in the examples, the difference in the mechanical characteristics of the front and rear drive systems is made the same as that of the reference example, and the dead zone gain (especially the front dead zone gain k f2 ) is set by the method described in the above embodiment.

[0235] In the reference example, the front and rear accelerations G become 0 at time t1, and after entering the dead zone, even for the same drive system (the front drive system S in the figure f ), the fluctuation of the stagnation time (time t2 to t3) in the dead zone due to the distribution of the driving force is large. And even for the same distribution of the driving force, in the front and rear drive systems, the stagnation time in the dead zone is different depending on the difference in the mechanical characteristics.

[0236] In contrast, referring to the control results (solid line) of the examples, regardless of the distribution of the driving force in the front drive system S f , the torque response timing is close to when all the driving force is distributed (K f= 1.0) (time t2). As a result, fluctuations in the dead time (times t2 to t3) in the dead zone are eliminated. This is because the dead zone is estimated for each of the front and rear drive systems, and the feedback gain multiplied by the torsional angular velocity ω df 、ω dr can be reduced in the dead zone. In particular, regarding the mechanical characteristics, the dead zone gain k f is specified based on the front drive system S f2 with a shorter dead zone, so that the torque response timing (time t2) when all the driving forces are distributed is advanced, and thus the time during which the electric vehicle 100 stays in the dead zone is further shortened.

[0237] [Modification Example]

[0238] Regarding the control logic related to the electric vehicle control method described in each of the above embodiments, by appropriately making necessary corrections, it can also be applied to each vehicle having the system structure shown in Figures 17 - 19 .

[0239] Specifically, Figure 17 the electric vehicle 200 shown does not have a drive system in the front, and has two first rear drive systems SrR and a second rear drive system SrL.

[0240] The first rear drive system SrR has a first rear drive motor 4rR that drives the first rear drive wheel 9rR, and various sensors and actuators for controlling the first rear drive motor 4rR. In addition, the second rear drive system SrL has a second rear drive motor 4rL that drives the second rear drive wheel 9rL, and various sensors and actuators for controlling the second rear drive motor 4rL.

[0241] The electric vehicle 200 of this modification example can execute the electric vehicle control method according to the present invention by, for example, respectively replacing the parameters of the front drive system Sf and the rear drive system Sr in the above embodiment with the parameters related to the first rear drive system SrR and the second rear drive system SrL, and applying corrections such as setting a preferred vehicle model.

[0242] In addition, Figure 18 the electric vehicle 300 shown has a front drive system Sf, a first rear drive system SrR, and a second rear drive motor 4rL. That is, in this electric vehicle system 300, the drive motor 4 is composed of three components: a front drive motor 4f that drives the front drive shaft Dsf, a first rear drive motor 4rR that drives the first rear drive wheel 9rR, and a second rear drive motor 4rL that drives the second rear drive wheel 9rL.

[0243] In the electric vehicle system 300 of this modification example, for example, by executing the same control method as the above-described embodiment and allocating the parameters set for the rear drive system Sr to the first rear drive system SrR and the second rear drive system SrL, it is possible to execute the electric vehicle control method according to the present invention.

[0244] And, Figure 19 The front drive system Sf of the electric vehicle 400 shown has: a first front drive system SfR, which is provided with various sensors and actuators for controlling the first front drive motor 4fR that drives the first front drive wheel 9fR; and a second front drive system SfL, which is provided with various sensors and actuators for controlling the second front drive motor 4fL that drives the second front drive wheel 9fL.

[0245] In addition, the rear drive system Sr is also composed of a first rear drive system SrR and a second rear drive system SrL. Therefore, the drive motor 4 of the electric vehicle system 400 is composed of four components: the first front drive motor 4fR, the second front drive motor 4fL, the first rear drive motor 4rR, and the second rear drive motor 4rL.

[0246] In the electric vehicle system 400 of this modification example, for example, execute the same control method as the above-described embodiment, and appropriately allocate the respective parameters of the front drive system Sf to the first front drive system SfR and the second front drive system SfL. On the other hand, appropriately allocate the respective parameters of the rear drive system Sr to the first rear drive system SrR and the second rear drive system SrL, whereby it is possible to execute the electric vehicle control method according to the present invention.

[0247] The embodiments of the present invention have been described above. The above embodiments only show a part of the application examples of the present invention, and the gist thereof is not to limit the technical scope of the present invention to the specific structures of the above embodiments.

Claims

1. A method for controlling an electric vehicle, in which a plurality of drive systems each having a drive motor are mounted on the electric vehicle, and the drive force of each drive system is controlled, wherein: The electric vehicle control method comprises the following processing: a basic torque distribution process for defining basic torque command values for the respective drive motors based on a total requested drive force for the electric vehicle and distribution of drive forces for the respective drive systems; A vibration reduction process in which each of the basic torque command values is corrected using a vibration compensation torque for suppressing vibration of a driving force transmission system to obtain a correction torque command value; and a driving force control process for controlling the driving force generated by each of the driving motors based on the correction torque command value; In the vibration reduction process, It is estimated whether each of the drive systems is in an insensitive interval, wherein the insensitive interval refers to an interval in which the output torque of the drive motor is not transmitted to the torque of the drive shaft. The vibration compensation torque is calculated by multiplying the estimated value of the torsional angular velocity of the drive shaft in each of the drive systems by a predetermined feedback gain. In the driving system in the dead zone, the feedback gain is set to a dead zone gain that changes according to an increase or decrease in the distribution of the driving force.

2. The electric vehicle control method according to claim 1, wherein: In the vibration reduction process, The dead zone gain is defined so that the timing at which the drive system leaves the dead zone is constant regardless of the distribution of the drive force.

3. The electric vehicle control method according to claim 1 or 2, wherein: In the vibration reduction process, The estimated value of the torsional angular velocity used for calculating the vibration compensation torque is calculated using a vehicle model that models a driving force transmission system of the electric vehicle.

4. The electric vehicle control method according to claim 3, wherein: In the vibration reduction process, The vehicle model is used to further obtain an estimated value of a torsion angle of a drive shaft of each drive system, and whether each drive system is in the insensitive zone is estimated by referring to the estimated value of the torsion angle.

5. The electric vehicle control method according to claim 1 or 2, wherein: The dead zone gain of the drive system to which a relatively large drive force is allocated in each drive system is set to be smaller than a normal gain that is set when the drive system is in a range other than the dead zone and is constant with respect to changes in drive force distribution.

6. The electric vehicle control method according to claim 1 or 2, wherein: The insensitive zone gain of one of the drive systems within each drive system having the characteristic that the insensitive zone is the shortest when all the driving force is distributed is set to be smaller than the normal gain that is set when the drive system is in a zone other than the insensitive zone and is constant with respect to changes in the driving force distribution.

7. An electric vehicle control device for controlling the driving force of each driving system in an electric vehicle equipped with a plurality of driving systems each having a driving motor, wherein: The electric vehicle control device comprises: A basic torque distribution unit that specifies a basic torque command value for each of the drive motors based on the total requested driving force for the electric vehicle and the distribution of the driving force for each drive system; A damping unit that uses a vibration compensation torque for suppressing vibrations in the driving force transmission system to correct each of the basic torque command values to obtain a corrected torque command value; And A driving force control unit that controls the driving force generated by each of the drive motors based on the corrected torque command value, The damping unit respectively estimates whether each drive system is in a dead zone, where the dead zone is a range of torque in which the output torque of the drive motor is not transmitted to the drive shaft, Calculates the vibration compensation torque by multiplying a specified feedback gain by an estimated value of the torsional angular velocity of the drive shaft in each drive system, In a drive system in the dead zone, sets the feedback gain to a dead zone gain that varies according to an increase or decrease in the distribution of the driving force.

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