Vehicle control device

Abstract

To compensate for interference of a torque peculiar to a mechanism, and simplify a control structure.SOLUTION: A control device 10 of a vehicle 1, which includes a differential mechanism 3 for imparting a torque difference to right and left wheels 5, and two electric motors 2 connected to the differential mechanism 3, includes an arithmetic part 11 for calculating each of right and left axle control torques on the basis of driver operation, a non-interference compensator 12 for cancelling an interference torque affecting the right-and-left reverse side caused by a wheel speed change of the right and left wheels 5 from the right and left axle control torques calculated by the arithmetic part 11, and a control part 13 for controlling each of the electric motors 2 on the basis of right and left second axle control torques from which interference has been cancelled by the non-interference compensator 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle equipped with a differential mechanism that applies a torque difference to left and right wheels and two electric motors connected to the differential mechanism. [Background technology]

[0002] Conventionally, in electric vehicles equipped with two independent electric motors, a differential mechanism (power distribution mechanism) is known that mechanically connects each electric motor to the left and right wheels, and if there is a difference in output torque between the left and right electric motors, amplifies the torque difference and transmits it to the left and right wheels (see, for example, Patent Documents 1 and 2). The provision of a differential mechanism with an amplifying function has the advantage of being able to generate a large torque difference between the left and right wheels. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4637136 [Patent Document 2] Patent No. 4907390 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the differential mechanism mechanically connects two electric motors to the left and right wheels, their rotations (torque) can interfere with each other. This interference can cause vehicle vibration. For example, if the vibration characteristics caused by torque interference change depending on the vehicle's turning state, the control procedures for suppressing the vibrations become complicated. Note that this same issue can also occur when the differential mechanism does not have an amplification function.

[0005] The present vehicle control device was devised in consideration of these problems, and one of its objectives is to simplify the control configuration by compensating for torque interference specific to the mechanism in a vehicle equipped with a differential mechanism capable of applying a torque difference to the left and right wheels and two electric motors. However, in addition to this objective, another objective of the present invention is to achieve operational effects that cannot be obtained by conventional techniques, which are derived from the various components shown in the below-described embodiments of the invention. [Means for solving the problem]

[0006] child The vehicle control device disclosed here is a vehicle control device equipped with a differential mechanism that imparts a torque difference to the left and right wheels and two electric motors connected to the differential mechanism, and is equipped with a calculation unit that calculates left and right axle control torques based on driver operation, a non-interference compensator that cancels out interference torques that affect opposite left and right sides due to changes in wheel speed of the left and right wheels from the left and right axle control torques calculated by the calculation unit, and a control unit that controls each of the electric motors based on the left and right second axle control torques whose interference has been canceled out by the non-interference compensator. In addition, the decoupling compensator cancels out the interference torque by taking into account dynamic factors of the target plant, which includes the left and right axles and a plant located upstream of the axles in the power transmission path from the electric motor to the left and right wheels. [Effects of the Invention]

[0007] According to the disclosed vehicle control device, by implementing a decoupling compensator, interference torques acting from opposite left and right sides are canceled out, allowing the differential mechanism to be treated as equivalently independent of the left and right. Therefore, torque interference specific to the mechanism can be compensated for by control, and the configuration of various controls, including vibration suppression control, can be simplified. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a vehicle to which a control device according to an embodiment is applied; [Figure 2] 1 is a skeleton diagram for explaining a configuration example of a differential mechanism mounted on a vehicle according to an embodiment; [Figure 3] FIG. 3 is a velocity diagram of the differential mechanism shown in FIG. 2. [Figure 4] FIG. 2 is a block diagram showing an example of a control device shown in FIG. 1. [Figure 5] 5 is a block diagram illustrating a model of a target plant taken into account by a decoupling compensator included in the control device of FIG. 4. FIG. [Figure 6] FIG. 10 is a block diagram showing an example of a control device including a decoupling compensator according to a modified example. [Figure 7] 10 is an example of a flowchart executed by a control device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A vehicle control device according to an embodiment will be described with reference to the drawings. The following embodiments are merely examples, and are not intended to exclude various modifications or applications of techniques not explicitly described in the following embodiments. The configurations of the respective embodiments can be modified in various ways without departing from the spirit of the embodiments. Furthermore, the configurations can be selected or combined as needed.

[0010] [1. Vehicle configuration] FIG. 1 is a schematic diagram of a vehicle 1 equipped with a control device 10 of this embodiment. The vehicle 1 is equipped with two motors 2 (electric motors) that drive left and right wheels 5 (rear wheels in this case). In the following description, the letter "L" or "R" suffixed to a reference symbol indicates the location of the element associated with that reference symbol (whether it is on the left or right side of the vehicle 1). For example, 5L indicates one of the left and right wheels 5 located on the left side of the vehicle (i.e., the left wheel), and 5R indicates the other located on the right side (i.e., the right wheel).

[0011] The two motors 2 have the function of driving at least either the front wheels or the rear wheels of the vehicle 1, and may have the function of driving all four wheels. Hereinafter, of the two motors 2, one located on the left side will be referred to as the left motor 2L, and the other located on the right side will be referred to as the right motor 2R. The left motor 2L and the right motor 2R operate independently of each other and can individually output driving forces of different magnitudes. In this embodiment, the left motor 2L and the right motor 2R have the same rated output and are provided as a pair.

[0012] The vehicle 1 is equipped with a power distribution mechanism 3 (differential mechanism) that applies a torque difference to the left and right wheels 5. The power distribution mechanism 3 of this embodiment has the function of amplifying the torque difference between the two motors 2 and then distributing the torque to each of the left and right wheels 5. As shown in FIG. 2, the power distribution mechanism 3 includes a pair of speed reduction mechanisms 3g (gear trains surrounded by dashed lines in FIG. 2) that reduce the rotational speed of each motor 2. The speed reduction mechanisms 3g are mechanisms that increase the torque (driving force) output from the motors 2 by reducing the torque. The reduction ratio G of the speed reduction mechanisms 3g is set appropriately depending on the output characteristics and performance of the motors 2. In this embodiment, the reduction ratios G of the left and right speed reduction mechanisms 3g are the same. Note that if the torque performance of the motors 2 is sufficiently high, the speed reduction mechanisms 3g may be omitted. The pair of motors 2 are connected to the power distribution mechanism 3, and the torque is amplified by reducing the rotational speed of the motors 2 and then transmitted (distributed) to each of the left and right wheels 5.

[0013] As shown in Figures 1 and 2, the power distribution mechanism 3 is a differential mechanism with a yaw control function (AYC function), and is interposed between the axle 4 (left axle 4L) connected to the left wheel 5L and the axle 4 (right axle 4R) connected to the right wheel 5R. The yaw control function is a function that adjusts the yaw moment by actively controlling the ratio of the driving force (driving torque) shared between the left and right wheels 5, thereby stabilizing the posture of the vehicle 1. A planetary gear mechanism, a differential gear mechanism, and the like are built into the power distribution mechanism 3. Note that a vehicle drive device including a pair of motors 2 and the power distribution mechanism 3 is also called a DM-AYC (Dual-Motor Active Yaw Control) device.

[0014] An example of the power split mechanism 3 will now be described with reference to Fig. 2. The power split mechanism 3 shown in Fig. 2 has a pair of speed reduction mechanisms 3g set to a speed reduction ratio G, and a planetary gear mechanism that has a function of amplifying the torque difference by a predetermined amplification factor. The power split mechanism 3 is preferably disposed between the left and right motors 2L, 2R in the vehicle width direction.

[0015] The planetary gear mechanism is a double-pinion planetary gear in which the sun gear 3s1 and ring gear 3r are input elements, and the sun gear 3s2 and carrier 3c are output elements. Torque from the left motor 2L is input to the sun gear 3s1, and torque from the right motor 2R is input to the ring gear 3r. The input element is arranged to rotate integrally with an idler gear 37 (described later), and the output element is arranged to rotate integrally with the output shaft 33.

[0016] Each reduction gear 3g is configured to reduce the rotational speed of each motor 2 in two stages by four gears 34, 35, 36, and 37 provided on three parallel-arranged shafts 31, 32, and 33. Hereinafter, the three shafts will be referred to as the motor shaft 31, counter shaft 32, and output shaft 33, in that order from the upstream side of the power transmission path from each motor 2 to the left and right wheels 5. Two of these shafts 31 to 33 are provided in each power distribution mechanism 3. The two motor shafts 31, two counter shafts 32, and two output shafts 33 located on the left and right are each configured identically (symmetrically). Furthermore, the reduction gears 3g provided on these shafts 31 to 33 are also configured identically (symmetrically) on the left and right.

[0017] The motor shaft 31 is positioned coaxially with the rotation shafts of the left and right motors 2 and has a first fixed gear 34. A second fixed gear 35 that meshes with the first fixed gear 34 and a third fixed gear 36 that has a smaller diameter than the second fixed gear 35 are provided on the counter shaft 32. The larger-diameter second fixed gear 35 is positioned more inward in the vehicle width direction than the smaller-diameter third fixed gear 36. An idler gear 37 that meshes with the third fixed gear 36 is provided on the output shaft 33. The first fixed gear 34 and the second fixed gear 35 form a first-stage reduction gear train, and the third fixed gear 36 and the idler gear 37 form a second-stage reduction gear train. The left idler gear 37 is connected to a sun gear 3s1, and the right idler gear 37 is connected to a ring gear 3r.

[0018] The reduction ratio G of the reduction mechanism 3g can be expressed as the ratio (or the ratio of the number of gear teeth) between the rotational angular velocity transmitted from the motor 2 to the reduction mechanism 3g and the rotational angular velocity transmitted from the reduction mechanism 3g to the power distribution mechanism 3. Furthermore, symbols b1 and b2 in FIG. 2 are reduction ratios (equivalent second speed ratios) determined by the structure of the gears built into the power distribution mechanism 3. Here, symbol b1 represents the reduction ratio of the path through which the driving force of the left motor 2L is transmitted to the right wheel 5R, and symbol b2 represents the reduction ratio of the path through which the driving force of the right motor 2R is transmitted to the left wheel 5L.

[0019] As shown in FIG. 1, each of the motors 2L, 2R is electrically connected to a battery 7 via an inverter 6 (6L, 6R). The inverter 6 is a converter (DC-AC inverter) that converts between the power of the DC circuit on the battery 7 side (DC power) and the power of the AC circuit on the motor 2 side (AC power). The battery 7 is, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is a secondary battery that can supply a high-voltage DC current of several hundred volts. When the motor 2 is powered, the DC power is converted into AC power by the inverter 6 and supplied to the motor 2. When the motor 2 is generating power, the generated power is converted into DC power by the inverter 6 and charged into the battery 7.

[0020] The control device 10 is one of the electronic control units (ECU, Electronic Control Unit) mounted on the vehicle 1. The control device 10 is equipped with, for example, a processor (microprocessor) such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile memory, etc. The processor is an arithmetic processing device incorporating a control unit (control circuit), an arithmetic unit (arithmetic circuit), a cache memory (group of registers), etc. The ROM, RAM, and non-volatile memory are memory devices that store programs and data in progress. The contents of the decisions and controls performed by the control device 10 are recorded and saved in memory as firmware or application programs, and when a program is executed, the contents of the program are expanded in memory space and executed by the processor.

[0021] Sensors for acquiring various types of information about the vehicle 1 are connected to the control device 10. In the example shown in Fig. 1, an accelerator opening sensor 21, a brake sensor 22, a steering angle sensor 23, a vehicle speed sensor 24, a wheel speed sensor 25, and a motor rotation speed sensor 26 are connected to the control device 10. The control device 10 controls each inverter 6 based on the various types of information detected by these sensors 21 to 26, thereby controlling each motor 2.

[0022] The accelerator opening sensor 21 is a sensor that detects the amount of depression of the accelerator pedal (accelerator opening) and the depression speed. The brake sensor 22 is a sensor that detects the amount of depression of the brake pedal (brake pedal stroke) and the depression speed. The steering angle sensor 23 is a sensor that detects the steering angles of the left and right wheels 5 (actual steering angle or steering angle of the steering wheel), and the vehicle speed sensor 24 is a sensor that detects the vehicle speed (vehicle speed).

[0023] The wheel speed sensor 25 (25L, 25R) detects the wheel angular velocity ω of the left wheel 5L. L and the wheel angular velocity ω of the right wheel 5R RThe motor rotation speed sensors 26 (26L, 26R) are sensors for detecting the rotation angular velocities ω of the left and right motors 2L, 2R, respectively, and are provided respectively near the left wheel 5L and the right wheel 5R. Lm ,ω Rm These are sensors (for example, resolvers, hall sensors, encoders) that detect the above, and are provided individually for the left motor 2L and the right motor 2R.

[0024] In a two-input, two-output mechanism such as the power distribution mechanism 3 described above, the motors 2 are mechanically coupled to the left and right wheels 5, which can cause interference between torques on the opposite sides of the power transmission path from the motors 2 to the left and right wheels 5. The torques on the opposite sides of the power transmission path (hereinafter referred to as "interference torques") are torques that affect the left and right wheels 5 due to changes in the wheel speeds of the left and right wheels 5. The interference torques are generated by dynamic factors (specifically, inertia, viscosity, and rigidity) of the target plant, including the left and right axles 4L and 4R, and the plants (motors 2, shafts 31-33, carrier 3c, various gears, etc.) located upstream of the axles 4 in the power transmission path, as well as friction between the devices and components included in the target plant. Here, focusing on the inertia of the target plant, a configuration for canceling the inertial torque will be described using FIG. 2 as a specific example.

[0025] The power distribution mechanism 3 in FIG. 2 is equipped with a planetary gear mechanism as described above. A speed diagram relating to the input and output of this power distribution mechanism 3 is shown in FIG. 3. In the diagram, b1 and b2 are the reduction ratios (equivalent second speed ratios) described above, and T Lm ,T Rm is the torque commanded to each motor 2L, 2R (hereinafter referred to as "motor control torque"), and T Lds ,T Rds is the torque transmitted to each axle 4L, 4R (hereinafter referred to as "upstream axle input torque"). Lm ,ω Rm is the motor rotation angular velocity, and ω Lds ,ω Rds is the rotational angular velocity of each axle 4L, 4R (upstream axle rotational angular velocity). From FIG. 3, the torque relational expression (Equation 1) and the rotational angular velocity relational expression (Equation 2) can be expressed as follows:

[0026]

number

[0027] In addition, the motor control torque T Lm ,T Rm is expressed as the motor driving torque T of each motor 2 as shown in the following equation 3. LDm ,T RDm From Motor Inertia Tank T LIm ,T RIm It is calculated by subtracting the motor inertia torque T LIm ,T RIm is expressed by the following equation 4. G is the reduction ratio, J m is the motor inertia.

[0028]

number

[0029] From the above equations 1 to 4, the upstream input torque T of the axle including the inertia on the axle 4 is Lds ,T Rds When calculated, the following equation 5 is obtained.

number

[0030] As shown in the third term on the right side of Equation 5 above, the upstream input torque T Lds The formula for the right axle Upstream rotational angular velocity ω Rds The differential value of (i.e., axle rotation angular acceleration) appears, and the right axle upstream input torque T Rds The formula for the left axle Upstream rotational angular velocity ω Lds The differential value of (i.e., axle rotation angular acceleration) appears. In this way, the upstream input torque T Lds ,T Rds It can be seen that the inertia torques on the opposite left and right sides (the third term on the right side of Equation 5) interfere with each other.

[0031] This inertia torque is one of the above-mentioned interference torques. The presence of interference torque may make it difficult to realize torque that satisfies the driver's request in the vehicle 1, or may cause unexpected vibrations in the vehicle 1. Furthermore, the control configuration for dealing with this, i.e., the control configuration for realizing torque that satisfies the driver's request and suppressing vibrations, may become complicated. Therefore, the control device 10 of this embodiment compensates for the interference torque in advance through control, making it possible to treat the power distribution mechanism 3 as equivalently independent of the left and right, thereby simplifying the control configuration.

[0032] [2. Control configuration] As shown in Fig. 1, the control device 10 includes a calculation unit 11, a decoupling compensator 12, and a control unit 13. These elements are shown by conveniently classifying the functions of the control device 10. Each of these elements can be written as an independent program, or multiple elements can be written as a composite program. The programs corresponding to each element are stored in the memory or storage device of the control device 10 and executed by the processor.

[0033] The calculation unit 11 calculates left and right axle control torques based on the driver's operation. The decoupling compensator 12 cancels the interference torque from the left and right axle control torques calculated by the calculation unit 11. The control unit 13 then controls each motor 2 based on the left and right axle control torques (hereinafter referred to as "second axle control torques") whose interference has been canceled out by the decoupling compensator 12.

[0034] Each of the elements 11 to 13 will be described in detail below with reference to FIGS. 4 to 6. FIG. 4 is a block diagram showing an example of the control device 10, and FIG. 5 is a block diagram showing an example of a model of the target plant 40 taken into account by the decoupling compensator 12. FIG. 6 is a block diagram showing an example of a control device 10' equipped with a decoupling compensator 12' according to a modified example. The arithmetic processing and control configuration of the control devices 10, 10' including the decoupling compensators 12, 12' are designed based on the model of the target plant 40. Note that the control device 10 in FIG. 4 and the control device 10' in FIG. 6 are identical in configuration except for the decoupling compensators 12, 12', and therefore the same configuration will be described with reference to FIG. 4.

[0035] The calculation unit 11 uses, as the driver operation, various pieces of information detected by, for example, an accelerator opening sensor 21, a brake sensor 22, and a steering angle sensor 23. The calculation unit 11 of this example first calculates the axle required torque T L-ref ,T R-ref Then, the axle control torque T' is calculated. L-ref ,T′ R-ref In the former calculation, the speed of the vehicle 1 may be taken into consideration in addition to the driver's operation. The calculation unit 11, for example, calculates the total drive torque, determines a target value of the torque difference to be applied to the left and right wheels 5, and calculates the left axle required torque T L-ref and right axle torque requirement T R-ref The method for calculating the axle required torque is not particularly limited.

[0036] The calculation unit 11 in this example calculates the axle required torque T L-ref ,T R-ref By performing axle torque control using the input value, the axle control torque T' L-ref ,T′ R-ref The axle torque control is a control that realizes the axle torque according to the axle request torque based on the driver's operation, and calculates the upstream rotational angular acceleration (ω Lds ,ω RdsAs shown in Fig. 4, the shaft torque control includes one feedforward control (FF control), one feedback control (FB control), and a shaft torque observer, which are provided on each of the left and right sides.

[0037] The axle torque observer converts the inertia torque calculated from the upstream axle rotational angular acceleration into the second axle control torque T L-ref ,T″ R-ref This is an estimator that estimates the actually generated shaft torque (estimated shaft torque) by subtracting it from the upstream axle rotational angular acceleration. The inertia torque is calculated by multiplying the upstream axle rotational angular acceleration by the upstream axle motor equivalent inertia. The calculation unit 11 may calculate the upstream axle rotational angular acceleration using three methods described below.

[0038] In FF control, the torque required by each axle T L-ref ,T R-ref In the FB control, the axle torque requirement T L-ref ,T R-ref Based on the deviation between the axle torque and the estimated axle torque, the FB amount to be added to the axle control torque after the FF control is calculated. L-ref ,T R-ref The deviation between the estimated axle torque and the FB amount is added to the axle control torque after FF control to calculate the axle control torque T' L-ref ,T′ R-ref The method of calculating the axle control torque is not limited to this, and for example, the axle torque control may be omitted and the axle request torque based on the driver's operation may be used as the axle control torque as is, or the axle control torque may be calculated by multiplying the axle request torque based on the driver's operation by some coefficient or by adding or subtracting some numerical value.

[0039] The decoupling compensators 12, 12' are compensators that cancel out interference torque that affects opposite left and right sides. The decoupling compensator 12 shown in Fig. 4 cancels out interference torque caused by a change in wheel speed that occurs due to a difference in torque applied to the left and right wheels 5. The decoupling compensator 12' shown in Fig. 6 is a compensator that cancels out interference torque caused by a change in wheel speed that occurs depending on the running state of the vehicle 1.

[0040] When a torque difference is applied to the left and right wheels 5, one wheel 5 to which a larger torque is applied accelerates, and the other wheel 5 to which a smaller torque is applied decelerates, enabling smooth turning. However, when the wheel speeds of the left and right wheels 5 change (one accelerates and the other decelerates), part of the inertia torque of the target plant 40 acts on the vehicle 1 as an interference torque that inhibits the torque difference that promotes turning. The decoupling compensator 12 in FIG. 4 compensates for the interference torque that occurs when a torque difference is applied to the left and right wheels 5.

[0041] Furthermore, even when no torque difference is applied to the left and right wheels 5 (i.e., when torque control is not performed), the outer wheel accelerates and the inner wheel decelerates during turning. However, even in this case, if the wheel speeds of the left and right wheels 5 change (one accelerates and the other decelerates), part of the inertia torque of the target plant 40 acts on the vehicle 1 as an interference torque that hinders turning. Even when not turning, for example, if only one wheel 5 rides on a slippery road surface or if one wheel slips, only one wheel 5 accelerates, and the wheel speeds of the left and right wheels 5 change. In this way, an interference torque is generated when a change in the wheel speeds of the left and right wheels 5 occurs depending on the running state of the vehicle 1. The decoupling compensator 12′ in FIG. 6 compensates for the interference torque generated by the difference in wheel speed between the left and right wheels.

[0042] The decoupling compensator 12 in Fig. 4 is designed to cancel out the interference torque in consideration of the dynamic factors of the target plant 40. As described above, the target plant 40 includes the left and right axles 4L and 4R, and the plants (motor 2, shafts 31 to 33, carrier 3c, various gears, etc.) located upstream of each axle 4 in the power transmission path. In the target plant 40, as shown in the model in Fig. 5, the output torque T LM ,T RM is the upstream input torque of the axle T Lds ,T Rds After being converted into L ,T R and transmitted to the left and right wheels 5.

[0043] The transfer function Gp(s) is derived by formulating and solving the equations of motion for the upstream axle, the downstream axle, and the axle torsional torque for each of the left and right sides. The transfer function Gp(s) is expressed as a 2 x 2 determinant, for example, as shown in the following equation 6, and the axle torsional torque T L ,T R is expressed by Equation 7. As is clear from Equation 7, the left axle twisting torque T L The upstream input torque T of the right axle is Rds This causes a torsional torque T on the right axle. R The upstream input torque T on the left axle Lds is affected.

[0044]

number

[0045] The decoupling compensator 12 calculates the interference torque (here, the upstream input torque T Rds ,T Lds ) is expressed as the determinant of Equation 8 below so as to cancel out

number

[0046] By implementing the decoupling compensator 12, the axle torsional torque T L ,T R is expressed by the following equation 9. As is clear from equation 9, the axle torsional torque T L ,T R Therefore, the interference torque affecting the opposite left and right sides is canceled out.

number

[0047] The decoupling compensator 12' shown in FIG. 6 is also designed to cancel out the interference torque in consideration of the dynamic factors of the target plant 40. However, the decoupling compensator 12' is composed of one first compensator 12A and left and right second compensators 12B. Like the decoupling compensator 12 in FIG. 4, the first compensator 12A is designed, for example, as a determinant that cancels out the interference torque. The second compensator 12B calculates the interference torque from the wheel speeds in advance and outputs this to the first compensator 12A. This compensates for the interference torque generated by the difference in wheel speeds between the left and right wheels.

[0048] The upstream axle rotational angular accelerations on the left and right opposite sides are input to the left and right second compensators 12B. In this modification, the calculation unit 11 calculates the upstream axle rotational angular accelerations. The following three methods can be used as calculation methods, and any one of them may be used, or a combination of multiple methods may be used to adopt an average value or a median value. First method: Calculation based on left and right wheel speeds Second method: Calculation based on the rotation speed of the left and right motors 2 Third method: Calculation based on steering angle and vehicle speed

[0049] When the first method is used, the calculation unit 11 calculates the angular velocities ω of the left and right wheels detected by the wheel speed sensors 25L and 25R. L ,ω R (sensor value) is differentiated to calculate the wheel angular acceleration as the upstream axle rotational angular acceleration as shown in the following equation 10.

number

[0050] When the second method is used, the calculation unit 11 calculates the left and right motor rotation angular velocities ω detected by the motor rotation speed sensors 26L and 26R. Lm ,ω Rm (sensor value) and calculates the upstream axle rotational angular acceleration based on the motor rotational angular acceleration. For example, in the case of vehicle 1 equipped with power distribution mechanism 3 shown in FIG. 2, calculation unit 11 calculates the upstream axle rotational angular acceleration using the following equation 11.

[0051]

number

[0052] When the third method is used, the calculation unit 11 calculates the upstream axle rotational angular acceleration based on, for example, the steering angles (sensor values) of the left and right wheels 5 detected by the steering angle sensor 23 and the vehicle speed (sensor value) detected by the vehicle speed sensor 24. Alternatively, instead of using the sensor value of the vehicle speed sensor 24, the vehicle speed may be estimated from the left and right wheel speeds, and the upstream axle rotational angular acceleration may be calculated using the estimated vehicle speed value. As a calculation method, for example, the third method described in International Application PCT / JP2021 / 013226 can be adopted.

[0053] Each second compensator 12B of the decoupling compensator 12' calculates an interference torque using the upstream rotational angular acceleration of the axle on the opposite left and right sides calculated by the calculation unit 11, and inputs the calculated interference torque to the first compensator 12A. The first compensator 12A calculates the left and right axle control torque T' using the inverse of each of the left and right interference torques. L-ref ,T′ R-ref For example, the decoupling compensator 12' cancels the axle control torque T' L-ref ,T′ R-ref The axle control torque T' can be calculated by adding a value with the opposite sign and the same absolute value as the interference torque, or by multiplying it by the reciprocal of the interference torque. L-ref ,T′ R-ref The interference torque contained in the second axle control torque T" is cancelled out. L-ref ,T″ R-ref is output to the control unit 13.

[0054] The control unit 13 controls the second left axle control torque T L-ref Based on this, the left motor 2L is controlled, and the right second axle control torque T″ R-ref The control unit 13 controls the right motor 2R based on, for example, the left and right second axle control torques T" L-ref ,T″ R-ref are the left and right motor control torques T Lm ,T Rm and controls each of the motors 2L and 2R. L-ref ,T″ R-ref Since the interference torque is cancelled out from the left and right, the power distribution mechanism 3 can be treated as being equivalently independent of each other, which simplifies the control configuration.

[0055] [3. Flowchart] 7 is an example of a flowchart executed by the above-mentioned control device 10. This flowchart is repeatedly executed at a predetermined calculation period under predetermined conditions, for example, from when the vehicle 1 is in a Ready ON state until it is in a Ready OFF state, or while the vehicle is traveling (when the vehicle speed is not 0).

[0056] The control device 10 first acquires vehicle information detected by the various sensors 21 to 26 (step S1). Next, the calculation unit 11 calculates the required torques T L-ref ,T R-ref (Step S2), and then axle torque control is performed to obtain the left and right axle control torques T' L-ref ,T′ R-ref Next, in the decoupling compensators 12, 12′, the second axle control torque T″ is calculated by canceling out the interference torque from the left and right axle control torques. L-ref ,T″ R-ref (Step S4). The control unit 13 calculates the second axle control torque T" L-ref ,T″ R-ref from the motor control torque T Lm ,T Rm (Step S5), the left and right motors 2L and 2R are controlled (Step S6), and the flow chart is returned.

[0057] [4. Actions and Effects] In the control device 10 described above, by implementing the decoupling compensators 12, 12', the interference torque acting from the opposite left and right sides is cancelled out, and the left and right power distribution mechanisms 3 can be treated as equivalently independent. In this way, in a vehicle 1 equipped with a power distribution mechanism 3 that mechanically couples two motors 2L, 2R to the left and right wheels 5, the torque interference specific to the mechanism can be compensated for by control, which simplifies the configuration of various controls (for example, FF control and FB control) including vibration suppression control.

[0058] By providing the power distribution mechanism 3 described above, it is possible to apply a torque difference to the left and right wheels 5. When a torque difference is applied, the wheel speed of the outer wheel during a turn increases, and the wheel speed of the inner wheel during a turn decreases, resulting in a change in wheel speed. Even if an interference torque occurs due to a change in wheel speed caused by the torque difference applied to the left and right wheels 5, the interference torque can be canceled out and its influence eliminated by implementing the decoupling compensator 12 shown in FIG. 4. This makes it possible to construct a virtual plant in which the FF control and FB control performed within the control device 10 can be controlled by regarding the left and right wheels as independent mechanisms, thereby simplifying the control configuration.

[0059] The calculation unit 11 calculates the axle control torque by performing axle torque control including FB control using the upstream axle rotational angular acceleration, and therefore the axle control torque T' input to the decoupling compensators 12, 12' is L-ref ,T′ R-ref This can improve the calculation accuracy. Furthermore, the calculation unit 11 calculates the second axle control torque T" in the axle torque observer. L-ref ,T″ R-ref The actual estimated axle torque is estimated using the L-ref ,T R-ref The feedback control is performed using the deviation between the estimated axle torque and the axle control torque T'. L-ref ,T′ R-refThis can further improve the calculation accuracy.

[0060] 6, it is also possible to cancel out interference torque caused by changes in wheel speed when a torque difference is not applied, such as when the vehicle 1 is turning or slipping. This makes it possible to expand the range of applications for the decoupling compensator 12' and further simplify the control configuration.

[0061] The calculation unit 11 calculates the upstream axle rotational angular acceleration using one of three methods, and then calculates the interference torque using this. Specifically, when the first method is used, the left and right wheel angular velocities ω detected by the wheel speed sensors 25L and 25R are L ,ω R The upstream axle rotational angular acceleration can be calculated by a simple calculation because it is only necessary to differentiate the sensor value. In addition, when the second method is used, the left and right motor rotational angular velocities ω Lm ,ω Rm Since the calculation is based on both the upstream axle rotational angular acceleration (sensor value) and the upstream axle rotational angular acceleration (sensor value), the calculation can accurately calculate the upstream axle rotational angular acceleration and the interference torque can be canceled out with high accuracy.

[0062] Furthermore, when the vehicle 1 is turning, the upstream axle rotational angular acceleration can also be calculated from the steering angle and vehicle speed using the third method. When the first or second method is used in combination with the third method, the interference torque can be cancelled out with higher precision by using the average or median value of the upstream axle rotational angular acceleration calculated using multiple methods. The decoupling compensators 12 and 12' are designed taking into consideration the dynamic factors (inertia, viscosity, stiffness) of the target plant, and therefore can cancel out the interference torque with higher precision.

[0063] [5. Other] The configuration of the control device 10 described above is an example and is not limited to the above. For example, the above-described decoupling compensators 12, 12' are designed to focus on the inertia of the target plant and cancel out the inertia torque, which is one type of interference torque. However, a decoupling compensator that cancels out the interference torque may be designed taking into account not only the inertia of the target plant but also its rigidity and viscosity. Furthermore, the decoupling compensator may be designed based on the configuration of the two electric motors and differential device mounted on the vehicle 1.

[0064] The configuration of the vehicle 1 described above is an example and is not limited to the above. For example, the configuration of the power distribution mechanism 3 is not limited to that shown in FIG. 2, and various planetary gear mechanisms and mechanisms other than planetary gear mechanisms can be used. The vehicle 1 may be a two-wheel drive (rear-wheel drive or front-wheel drive) vehicle or a four-wheel drive vehicle. . four In the case of a wheel-drive vehicle, a differential mechanism that applies a torque difference between the left and right wheels using two electric motors may be connected to at least one of the front and rear wheels. [Explanation of symbols]

[0065] 1 vehicle 2. Motor (electric motor) 2L left motor 2R Right motor 3 Power distribution mechanism (differential mechanism) 5 Left and right wheels, wheels 7 Battery 10 Control device 11 Arithmetic section 12,12' Decoupling compensator 12A first compensator 12B Second compensator 13 Control Unit 21 Accelerator opening sensor 22 Brake sensor 23 Steering angle sensor 24 Vehicle speed sensor 25, 25L, 25R wheel speed sensor 26, 26L, 26R Motor rotation speed sensor 40 Target plants

Claims

1. A control device for a vehicle including a differential mechanism that applies a torque difference to left and right wheels and two electric motors connected to the differential mechanism, a calculation unit that calculates left and right axle control torques based on a driver's operation; a non-interacting compensator that cancels out an interference torque that affects the left and right opposite sides due to a change in wheel speed of the left and right wheels from the left and right axle control torques calculated by the calculation unit; a control unit that controls each of the electric motors based on the left and right second axle control torques whose interference has been canceled by the decoupling compensator, The decoupling compensator cancels out the interference torque by taking into consideration dynamic factors of a target plant including left and right axles and a plant located upstream of the axles in a power transmission path from the electric motor to the left and right wheels. A vehicle control device comprising:

2. The decoupling compensator cancels out the interference torque caused by the change in wheel speed due to the torque difference applied to the left and right wheels.

2. The vehicle control device according to claim 1.

3. The calculation unit calculates the axle control torque by axle torque control that includes feedback control using upstream rotational angular acceleration of each of the left and right axles of the vehicle and realizes axle torque according to the left and right axle request torque based on the driver's operation.

3. The vehicle control device according to claim 2.

4. The axle torque control includes an axle torque observer that estimates an estimated axle torque, which is an actually generated axle torque, by subtracting an inertia torque calculated from the upstream axle rotational angular acceleration from the second axle control torque, The calculation unit uses the deviation between the axle request torque and the estimated axle torque in the feedback control.

4. The vehicle control device according to claim 3.

5. The decoupling compensator cancels out the interference torque caused by the wheel speed change due to the running state of the vehicle.

5. The vehicle control device according to claim 1, wherein the vehicle control device is a control device for controlling a vehicle.

6. the calculation unit calculates upstream rotational angular accelerations of the left and right axles of the vehicle based on sensor values of wheel speed sensors that detect the wheel speeds of the left and right wheels, or two sensor values of rotational speed sensors that detect the rotational speeds of the electric motors; The decoupling compensator calculates the interference torque using the upstream axle rotational angular acceleration calculated by the calculation unit, and uses an inverse element of the interference torque.

6. The vehicle control device according to claim 5.

7. the calculation unit calculates upstream rotational angular accelerations of the left and right axles of the vehicle based on the steering angles of the left and right wheels and the vehicle speed; The decoupling compensator calculates the interference torque using the upstream axle rotational angular acceleration calculated by the calculation unit, and uses an inverse element of the interference torque.

7. The vehicle control device according to claim 5 or 6.

Images