JP5971186B2 - Wheel control device, vehicle - Google Patents

Description

  The present invention relates to a technique for controlling a plurality of motors capable of independently driving or braking a plurality of wheels of a vehicle.

  In a vehicle equipped with a plurality of motors capable of independently driving or braking a plurality of wheels, it is necessary to deal with the problem of heat generation of each motor, and various measures have been conventionally taken against this problem. It has been. For example, in Patent Document 1 below, a motor temperature after detection is estimated from the motor temperature of a predetermined motor detected by a temperature sensor, and if the motor temperature is estimated to exceed a reference temperature, the driving force of the motor is estimated. A technique for distributing a part to another motor is disclosed. However, this technique does not consider the motor temperature during braking of the vehicle. In particular, when sudden braking occurs during normal driving, it is assumed that the motor temperature exceeds the reference temperature, so that braking by the motor is limited. In such a case, there is a problem that the maximum braking force cannot be exhibited. Therefore, when designing this type of wheel control, there is a high demand for building a control technique that takes into account the temperature change of the motor during braking.

JP 2009-247205 A

  The present invention has been made in view of the above points, and one of its purposes is to provide each motor at the time of braking in a vehicle including a plurality of motors that can independently drive or brake a plurality of wheels. It is providing the technique which suppresses that braking performance falls by the temperature change of.

  In order to achieve the above object, a wheel control device according to the present invention includes at least a detection unit and a control unit that detect a vehicle speed of the vehicle. The control unit drives the driving force to each of the plurality of motors based on the motor heat generation parameter relating to the heat generated in each motor when the vehicle is decelerated at a predetermined deceleration from the vehicle speed detected by the detection unit by the braking force of the plurality of motors. Fulfill the function of allocating. Thereby, the temperature of each motor can be suitably adjusted before braking by allocating the driving force of a plurality of motors according to the motor heat generation level during virtual braking. As a result, the temperature of each motor that changes due to actual braking when the driver depresses the brake pedal is less likely to exceed the reference temperature, and a reduction in braking performance caused by a temperature change of each motor during braking can be suppressed. In short, this control unit is a setting unit that preliminarily sets the distribution of the driving forces of the plurality of motors in consideration of the heat generated by each motor during actual braking. In this case, with respect to the distribution of the driving force, the driving force may be distributed based on the motor heat generation parameter that is uniquely determined from the vehicle speed and the deceleration, or the motor heat generation may be performed by adding further parameters to the vehicle speed and the deceleration. The driving force may be distributed based on the estimated motor heat generation parameter after estimating the parameter. In addition, the distribution of the driving force may be a distribution of the driving force in the power running direction, or may be a distribution of the driving force in the regeneration direction that is opposite to the power running direction. The “motor heat generation parameter” here includes various parameters that can indicate the heat generation level of the motor. Typically, the heat generation amount of the motor during braking, and the motor electrically loses during braking. The motor loss amount, the motor temperature during braking, the vehicle speed, and the like can be used as motor heat generation parameters.

In a wheel control device of the according to the present invention, the control unit estimates the motor heating parameters for each motor, you allocate a driving force to each of the plurality of motors in accordance with the motor heating parameter estimation. As a result, it is possible to allocate the driving force after estimating the motor heat generation parameter by adding further parameters to the vehicle speed and deceleration.

  Further, in the wheel control device according to the present invention, the control unit has a relatively low driving force of the motor estimated to be at a relatively high heat generation level among the plurality of motors based on the estimated motor heat generation parameter. It is preferable to distribute the driving force so as to be less than the driving force of the motor estimated to be at the heat generation level. In this case, for a motor that is estimated to have a high motor heat generation level during virtual braking, the effective temperature increase range for the motor during actual braking is expanded by relatively reducing the driving force of the motor. be able to. As a result, it is possible to reliably suppress a decrease in braking performance during actual braking.

  In the wheel control device according to the present invention, it is preferable that the control unit estimates the motor heat generation parameter when the vehicle is decelerated to a stop at a maximum deceleration as a predetermined deceleration. In this case, braking at the maximum deceleration is the most severe condition regarding the heat generation of the motor. Therefore, by distributing the driving force according to the motor heat generation parameters based on the assumption of braking at the maximum deceleration, it is possible to safely cope with a reduction in braking performance on all possible braking modes on the safe side. Is.

  In the wheel control device according to the present invention, it is preferable that the control unit uses a motor loss amount of each motor that changes in accordance with a load acting on each of the plurality of wheels as a motor heat generation parameter. Regarding the load change during braking, the load on the front wheel in the traveling direction (the front wheel in the forward direction, or the rear wheel in the reverse direction) is the load on the rear wheel in the traveling direction (the rear wheel in the forward direction, or in the reverse direction). It becomes larger than the load of the front wheel. In this case, the motor loss amount of the motor assigned to each wheel can be easily derived by applying a load change to a pre-stored calculation model.

  A vehicle according to the present invention includes a plurality of wheels, a plurality of motors that can independently drive or brake each of the plurality of wheels, and a motor control device that controls the plurality of motors. The control device is constituted by the wheel control device. Thereby, the vehicle which can suppress the fall of the braking performance which arises by the temperature change of each motor at the time of braking is realizable.

  As described above, according to the present invention, in a vehicle including a plurality of motors capable of independently driving or braking a plurality of wheels, it is possible to suppress a decrease in braking performance due to a temperature change of each motor during braking. It became possible to do.

FIG. 1 is a diagram showing a schematic configuration of a drive mechanism of a vehicle 10 according to the present invention. FIG. 2 is a diagram showing a schematic configuration of the control unit 30 in FIG. FIG. 3 is a diagram showing a processing flow relating to driving force distribution control. FIG. 4 is a diagram illustrating a calculation model of the motor output and the stop time. FIG. 5 is a diagram showing a calculation model of the motor loss amount. FIG. 6 is a diagram illustrating a friction circle during steady running and braking. FIG. 7 is a diagram illustrating a calculation model of the estimated motor temperature.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a schematic configuration of a drive mechanism of the vehicle 10. The vehicle 10 corresponds to a “vehicle” of the present invention, and includes left and right front wheels 11 and 12 and left and right rear wheels 13 and 14 as a plurality of wheels. The left and right front wheels 11, 12 are supported by a vehicle body 10 a as a spring on the vehicle 10 via suspension mechanisms 15, 16 independently of each other. The left and right rear wheels 13 and 14 are supported on the vehicle body 10a of the vehicle 10 via suspension mechanisms 17 and 18 respectively or independently of each other. In FIG. 1, an arrow F indicates the forward direction of the vehicle 10, and an arrow R indicates the reverse direction of the vehicle 10. An arrow D1 indicates the left-right direction of the vehicle 10, and an arrow D2 indicates the front-rear direction of the vehicle 10.

  The left and right front wheels 11 and 12 are driven by electric motors 19 and 20, respectively. Similarly, the left and right rear wheels 13 and 14 are driven by electric motors 21 and 22, respectively. When the motors 19 to 22 are mounted in the corresponding wheels 11 to 14, the motors 19 to 22 are called so-called in-wheel motors, and together with the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14, It is placed under the spring. Moreover, the motors 19 to 22 may be mounted on springs, and in that case, the corresponding wheels 11 to 14 are driven via a drive shaft (not shown). And each motor 19-22 is controlled independently, respectively, and each of the left-right front wheels 11 and 12 and the right-and-left rear wheels 13 and 14 is made to drive direction (it is also called a "power running direction") or a braking direction ("regenerative direction"). The torque for driving is also controlled.

  These motors 19 to 22 are all configured as AC synchronous motors, for example. In this case, the DC power of the power storage device 24 (such as a battery or a capacitor) mounted on the vehicle 10 as a drive source is converted into AC power via the inverter 23, and the AC power is supplied to each motor. Each motor is driven to apply driving torque in the driving direction or braking direction to the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14. In addition, these motors 19 to 22 can be regeneratively controlled using the rotational energy of the left and right front wheels 11 and 12 and the left and right rear wheels 13 and 14. Each of the four motors 19 to 22 may have a structure directly connected to a corresponding wheel, or may have a configuration in which a speed reducer is interposed between the corresponding wheels. Or the motors 19-22 may be attached to the vehicle 10, and the structure which drives the corresponding wheels 11-14 via a drive shaft may be sufficient.

  Brake mechanisms 25, 26, 27, and 28 are provided between the four wheels 11 to 14 and the corresponding four motors 19 to 22, respectively. Each of the brake mechanisms 25 to 28 is configured as a known braking device (so-called “friction brake”) such as a disc brake or a drum brake. These brake mechanisms 25 to 28 are brakes that actuate, for example, pistons of brake calipers that generate braking force on the four wheels 11 to 14 and brake shoes (both not shown) by hydraulic pressure from a master cylinder (not shown). The actuator 29 is connected. The inverter 23 and the brake actuator 29 are each connected to the control unit 30.

  In the vehicle 10 described above, each of the two left and right front wheels 11 and 12 is provided in addition to a configuration in which each of the four wheels 11 to 14 is driven by each of the four motors 19 to 22 (that is, a four-wheel motor vehicle). A configuration in which each of the two motors 19 and 20 is driven (that is, a front-wheel-drive two-wheel motor vehicle), and a configuration in which each of the two left and right rear wheels 13 and 14 is driven by each of the two motors 21 and 22 (that is, A rear-wheel drive two-wheel motor vehicle can also be employed.

  The control unit 30 includes a detection unit 30a and a control unit 40 that are electrically connected to each other. The detection part 30a is comprised by the 1st detection sensor 31, the 2nd detection sensor 32, and the 3rd detection sensor 33, and the output signal from the various sensors containing these 1st-3rd detection sensors 31-33 is a control part. 40. The first detection sensor 31 is configured as a detection sensor (operation state detection means) for detecting an operation state operated by the driver for driving the vehicle 10. The second detection sensor 32 is configured as a detection sensor (motion state detection means) for detecting the motion state generated in the vehicle body 10a (on the spring) of the vehicle 10 as the travel state of the vehicle 10, particularly during travel. The third detection sensor 33 is configured as a detection sensor (disturbance detection means) for detecting a disturbance acting on the vehicle 10 during traveling.

  As the first detection sensor 31, for example, a steering angle sensor that detects a driver's operation amount (steering angle) with respect to a steering wheel (not shown) for steering a vehicle, or a driver's operation amount (depression) with respect to an accelerator pedal (not shown). An accelerator sensor that detects the amount, angle, pressure, etc.), a throttle sensor that is provided in an engine (not shown) and detects the opening of a throttle that operates according to the operation of the accelerator pedal, and an operation for a brake pedal (not shown) Brake sensor that detects the amount of operation (depression, angle, pressure, etc.) by the user, parking brake sensor that detects the on / off state of the parking brake (not shown), and on / off state of the ignition (not shown) An ignition sensor to be used.

  As the second detection sensor 32, for example, a sprung vertical acceleration sensor that detects vertical acceleration in the vertical direction of the vehicle body 10a (on a spring), a horizontal acceleration sensor ("lateral G sensor" that detects horizontal acceleration generated in the vehicle body 10a, for example. The vehicle speed sensor for detecting the vehicle speed of the vehicle 10, the yaw rate sensor for detecting the yaw rate generated in the vehicle 10, the pitch rate sensor for detecting the pitch rate generated in the vehicle 10, and the roll rate generated in the vehicle 10 are detected. Roll rate sensor.

  As the third detection sensor 33, for example, a stroke sensor that detects the stroke amount of each of the suspension mechanisms 15 to 18, and an unsprung vertical movement that detects vertical acceleration in the vertical direction under the spring of the vehicle 10 including the four wheels 11 to 14. Examples include an acceleration sensor.

  The control unit 40 outputs a control signal for controlling the motors 19 to 22 to the inverter 23 based on output signals from various sensors including the first to third detection sensors 31 to 33, and also supplies the brake actuator 29 with the control signal. It fulfills the function of outputting a control signal for controlling the brake mechanisms 25-28. As a result, the control unit 40 can grasp and control the traveling state of the vehicle 10 and the behavior of the vehicle body 10a. The control unit 40 includes a microcomputer including a CPU, a ROM, a RAM, and the like as main components, and executes various programs. The control unit 30 including the control unit 40 constructs a wheel control device that controls the four wheels 11 to 14 provided in the vehicle 10 and controls the four motors 19 to 22. “Wheel control device” and “motor control device” are configured. The “wheel control device” and “motor control device” of the present invention can also be configured by a system in which the motors 19 to 22 and the inverter 23 are added to the control unit 30.

  As shown in FIG. 2, the control unit 40 includes an input unit 41 as an input unit, a vehicle body behavior control command value calculation unit 42 as a vehicle body behavior control value calculation unit, and a driving force distribution calculation unit as a driving force distribution calculation unit. 43, a torque calculation unit 44 as a torque calculation unit, and an output unit 45 as an output unit. The control unit 40 corresponds to the “control unit” of the present invention.

  Signals are input from the first detection sensor 31, the second detection sensor 32, and the third detection sensor 33 to the input unit 41. Based on the input signal from the first detection sensor 31, the input unit 41, for example, the steering angle of the steering wheel by the driver, the accelerator operation amount and throttle opening accompanying the operation of the accelerator pedal, and the operation of the brake pedal The amount of brake operation, the on / off state of the ignition, the state of charge of the power storage device 24, and the like are acquired. Further, the input unit 41 acquires, for example, the vehicle speed of the vehicle 10, the roll rate, the pitch rate, the yaw rate, and the like of the vehicle body 10a based on the input signal from the second detection sensor 32. Further, the input unit 41 acquires, for example, the size of the unevenness of the road surface on which the vehicle 10 is traveling, the size of the influence of the cross wind on the vehicle 10, based on the input signal from the third detection sensor 33. Thus, the input unit 41 outputs the acquired various detection values to the vehicle body behavior control command value calculation unit 42.

  The vehicle body behavior control command value calculation unit 42 calculates a target longitudinal driving force as a control command value for running the vehicle 10 using the various detection values from the input unit 41, and also displays the behavior generated in the vehicle body 10a. It fulfills the function of calculating control command values (target roll moment, target pitch moment and target yaw moment) for control. The vehicle body behavior control command value calculation unit 42 outputs the command values representing the calculated target longitudinal driving force, target roll moment, target pitch moment, and target yaw moment to the driving force distribution calculation unit 43.

  The driving force distribution calculating unit 43 distributes the target longitudinal driving force, the target roll moment, the target pitch moment, and the target yaw moment to the wheels 11 to 14 based on the command value from the vehicle body behavior control command value calculating unit 42. It fulfills the function of calculating each driving force to be generated. The driving force distribution calculating unit 43 outputs the calculated driving forces to the torque calculating unit 44.

  The torque calculation unit 44 functions to calculate the torque that should be generated by each of the motors 19 to 22 corresponding to each driving force calculated by the driving force distribution calculation unit 43. Further, in the torque calculation unit 44, the distribution torque is distributed to the reference torque in accordance with the input signal from the second detection sensor 32, for example, the second information relating to the movement state (roll movement, pitch movement and yaw movement) of the vehicle 10. The calculated torque is calculated. Then, the torque calculation unit 44 outputs the calculated torque to the output unit 45.

  The output unit 45 outputs a drive signal corresponding to the torque calculated by the torque calculation unit 44 to the inverter 23. As a result, the inverter 23 controls the drive power (drive current) supplied to the motors 19 to 22 to drive the motors 19 to 22. As a result, driving torque is generated in each of the wheels 11 to 14. As a result, the vehicle 10 can be appropriately traveled according to the operation state by the driver, and the roll motion, pitch motion, and yaw motion in the vehicle body 10a can be appropriately controlled.

  Further, the control unit 40 executes driving force distribution control for estimating the heat generation level of the motors 19 to 22 during virtual braking and distributing the driving force of the motors 19 to 22 in advance. The processing relating to the driving force distribution control is substantially executed by the driving force distribution calculating unit 43 of the control unit 40. Hereinafter, processing related to the driving force distribution control will be described.

  As shown in FIG. 3, the process related to the driving force distribution control includes processes from step S101 to step S105. This process may further include one or more separate steps. First, in step 101, the vehicle speed of the vehicle 10 is detected by a vehicle speed sensor that is one of the detection sensors 32 in the detection unit 30a. The detection unit 30a corresponds to the “detection unit” of the present invention.

  Subsequently, in steps S102 and S103, assuming that braking is performed by the motors 19 to 22 from the vehicle speed detected in step S101 to the stop, motor heat generation parameters relating to the heat generated in each motor in this case, in particular, the electric power of the motor The amount of motor loss that is a typical loss is estimated. As this virtual braking, it is assumed that only the braking force of the motors 19 to 22 is used without using the braking force of the brake mechanisms 25 to 28.

  Specifically, in step S102, the motor output required when the vehicle 10 is decelerated at the maximum deceleration (predetermined deceleration) by the braking force of the motors 19 to 22 until the vehicle 10 is stopped from the current vehicle speed detected by the vehicle speed sensor. Then, the stop time at that time is calculated. In this case, typically, a motor model (formula, map, etc.) preset based on the motor specifications, a tire model (formula, map, etc.) preset based on the tire specifications, and the braking specifications by the motor By applying various control parameters and driving information detected in real time to a calculation model including an ABS (anti-lock brake) control model (formula, map, etc.) preset based on the motor output and stop time Can be calculated.

ここで、ｈは車両１０の重心高、Ｗは車両１０の荷重、ａｘは車両１０の前後方向の加速度（減速度）、ｌは車両１０のホイールベースを示している。その結果、このステップＳ１０２で用いられるモータ出力は、車両１０の車速、最大減速度、及び車輪荷重に基づいて導出される。 For example, when the calculation model referred to in FIG. 4 is used, output parameters (vehicle speed, wheel speed, slip rate, etc.) output from the tire model are input to the ABS control model together with control parameters related to the control of the vehicle 10. On the other hand, the required braking force is input to the ABS control model together with the previous required braking force stored last time, and is also input to the motor model. In this case, the motor outputs of the four motors 19 to 22 are output from the motor model. Further, the effective braking force executed by the motor output is input to the tire model together with the wheel load acting on each of the four wheels 11 to 14 at the time of braking, so that the stop time of the vehicle 10 (that is, the vehicle 10 Is the time it takes for the vehicle to stop from the current vehicle speed). The wheel load is typically derived by adding the load change amount ΔW during braking to the initial load, or subtracting the load change amount ΔW during braking from the initial load. In this case, the load change amount ΔW can be obtained by the following equation (1).

Here, h is the height of the center of gravity of the vehicle 10, W is the load of the vehicle 10, ax is the acceleration (deceleration) in the longitudinal direction of the vehicle 10, and l is the wheelbase of the vehicle 10. As a result, the motor output used in step S102 is derived based on the vehicle speed, maximum deceleration, and wheel load of the vehicle 10.

  In step S103, the motor loss amounts of the motors 19 to 22 are calculated from the vehicle speed detected in step S101 and the motor output and stop time calculated in step S102. In this case, as shown in FIG. 5, the vehicle speed detected in step S101 and the motor output calculated in step S102 are applied to the three-dimensional map regarding the three parameters of vehicle speed, motor output and motor loss. Motor loss is calculated. Furthermore, the motor loss amount of each motor is calculated by integrating the motor loss with respect to the stop time calculated in step S102. This motor loss amount is an estimated value of a loss amount that each motor electrically loses when the vehicle 10 is decelerated at the maximum deceleration by the braking force of the motors 19 to 22 from the current vehicle speed to the stop.

  Subsequently, in step S104 and step S105, the driving force is distributed to each of the motors 19 to 22 in accordance with the motor loss amount estimated in step S103.

ここで、Ｌ_ＦＬはモータ１９のモータ損失量、Ｌ_ＦＲはモータ２０のモータ損失量、Ｌ_ＲＬはモータ２１のモータ損失量、Ｌ_ＲＲはモータ２２のモータ損失量を示している。 Specifically, in step S104, the motor loss ratio of each motor, that is, the ratio of the motor loss amount of each motor to the motor loss amount of the motor is calculated from the motor loss amount calculated in step S103. For example, by the following equation (2) to (5), left front wheel (FL) motor loss ratio _{LR FL} of the motor 19 of the 11, right front wheel (FR) motor loss ratio of 12 of the motor 20 _{LR FR,} a left rear wheel ( motor loss ratio _{LR FR} motor 21 RL) 13, a motor loss ratio _{LR RR} of the motor 22 of the right rear wheel (RR) 14 can be calculated.

Here, L _FL indicates a motor loss amount of the motor 19, L _FR indicates a motor loss amount of the motor 20, L _RL indicates a motor loss amount of the motor 21, and L _RR indicates a motor loss amount of the motor 22.

  By the way, since the load moves forward in the traveling direction of the vehicle during braking (deceleration), it relates to the front wheels in the traveling direction (the front wheels 11 and 12 in the forward direction or the rear wheels 13 and 14 in the reverse direction). While the load becomes larger than that during steady running, the load on the rear wheels in the traveling direction (rear wheels 13 and 14 in the case of forward movement or front wheels 11 and 12 in the case of backward movement) becomes smaller than that during steady running. For the load change in this case, reference is made to the friction circle shown in FIG. The friction circle represents a tire grip limit by a braking force that is a vertical grip and a turning force that is a horizontal grip. In this case, the size of the friction circle is defined as the product of the friction coefficient of the road surface and the load acting on each wheel. Therefore, in order to use up the friction circle as much as possible, it is preferable to distribute the driving force to each motor in consideration of a load change occurring at each wheel during braking, that is, a change in the size of the friction circle.

Regarding the distribution of the driving force, in step S105, based on the motor loss ratio calculated in step S104, a distribution ratio of driving force to be distributed to each motor (also referred to as “driving force distribution ratio”) is set. Specifically, the following equation (6) to (9), the driving force distribution ratio _{D FL} of the motor 19, the driving force distribution ratio _{D FR} of the motor 20, the driving force distribution ratio _{D FR} of the motor 21, the motor 22 The driving force distribution ratio D _RR can be calculated respectively.

A target driving force as a target value for each motor is set by the product of each of the driving force distribution ratios D _FL , D _FR , D _FR , and D _RR and the driving force required by the driver. In this case, the driving force relating to the whole of the four motors 19 to 22 is first distributed to the motors 19 and 20 and the motors 21 and 22 according to the front and rear driving force distribution ratios, and further, left and right in each of the front and rear motor groups. It is distributed to the motor 19 and the motor 20 by the driving force distribution ratio, and is distributed to the motor 19 and the motor 20 by the left and right driving force distribution ratio. As a result, heat generated by the motors 19 and 20 that is estimated to be at a relatively high heat generation level during virtual braking based on the motor loss amount estimated in step S103 is relatively low. The driving force is distributed to the motors 19 to 22 so as to be lower than the driving force of the motors 21 and 22 estimated to be at the level. In this case, the driving force of the motors 19 and 20 estimated to have a high heat generation level at the time of virtual braking is set low, and the heat generation level before braking of the motor is suppressed in advance, so that the driver can It is possible to widen the effective temperature rise range for the motor at the time of actual braking when the pedal is depressed. As a result, it is possible to reliably suppress a decrease in braking performance during actual braking.

  As for this actual braking, the braking mode by the brake mechanism 25 which is a friction brake (normal braking when the wheel is unlocked, ABS braking when the wheel is locked) and braking mode by the motors 19 to 22 (the wheel is non-locking). It is possible to employ at least one of a regenerative brake in a locked state and an ABS brake in which a wheel is locked. In particular, when giving priority to brake responsiveness and brake accuracy during ABS braking, it is preferable to adopt a braking mode that uses only the braking force of the motors 19 to 22. On the other hand, when the performance of the power storage device 24 is taken into consideration during ABS braking, it is preferable to employ a braking mode that uses both the braking forces of the motors 19 to 22 and the brake mechanism 25 in cooperation. When the motors 19 to 22 are employed for all or a part of braking during ABS braking, the motor performance particularly during ABS braking is properly exhibited by applying the above-described driving force distribution control. As a result, the braking distance (stop distance) until the vehicle 10 stops can be suppressed.

  The driving force distribution control is preferably performed at all times on condition that the vehicle 10 is started. For example, when it is determined that the vehicle 10 has been started by an ignition sensor that is one of the detection sensors 31, the control shown in FIG. 3 can be executed. In this case, when the vehicle speed of the vehicle 10 begins to be detected by the vehicle speed sensor, which is one of the detection sensors 32, the driving force is distributed among the motors 19 to 22, and particularly with respect to the motor on the rear wheel side as the vehicle speed increases. The ratio of driving force distribution becomes high. By always performing the driving force distribution control, it is possible to always prepare for braking after the vehicle 10 is started, and it is effective to suppress the braking distance until the vehicle 10 stops at the time of sudden braking by improving the response. .

  As an example, in the first traveling state in which the vehicle 10 is moving forward at a predetermined vehicle speed, the driving force of the motors 21 and 22 on the rear wheels 13 and 14 side is set to the front wheels 11 and 12 side in consideration of load changes during braking. The driving force distribution of the motors 19 to 22 is performed so as to exceed the driving force of the motors 19 and 20. That is, in this first traveling state, the distribution of driving force can be shifted to the motors 21 and 22 on the rear wheels 13 and 14 side. Thereafter, in the second traveling state in which the vehicle speed is further increased than in the first traveling state, it is assumed that the load further shifts to the front wheels 11 and 12 during braking. In this case, since the heat generation expected in the motors 19 and 20 on the front wheels 11 and 12 side during braking exceeds the first traveling state, the distribution of the driving force is further shifted to the motors 21 and 22 on the rear wheels 13 and 14 side. be able to. As a result, as the vehicle speed in the forward direction of the vehicle 10 increases, the distribution of the driving force shifted to the motors 21 and 22 on the rear wheels 13 and 14 side increases.

  Similarly, in the third traveling state in which the vehicle 10 is moving backward at a predetermined vehicle speed, the driving force of the motors 19 and 20 on the front wheels 11 and 12 side is applied to the rear wheels 13 and 14 in consideration of load changes during braking. The driving force distribution of the motors 19 to 22 is performed so as to exceed the driving force of the motors 21 and 22 on the side. That is, in the third traveling state, the distribution of the driving force can be shifted to the motors 19 and 20 on the front wheels 11 and 12 side. Thereafter, in the fourth traveling state in which the vehicle speed is further increased than in the third traveling state, it is assumed that the load further shifts to the rear wheels 13 and 14 during braking. In this case, the heat generation expected in the motors 21 and 22 on the rear wheels 13 and 14 side during braking exceeds the third running state, so that the distribution of the driving force is further shifted to the motors 19 and 20 on the front wheels 11 and 12 side. be able to. As a result, the distribution of the driving force shifted to the motors 19 and 20 on the front wheels 11 and 12 side increases as the vehicle speed in the reverse direction of the vehicle 10 increases.

  According to the driving force distribution control described above, by distributing the driving force of the motors 19 to 22 according to the motor heat generation level during virtual braking, the temperature of each motor can be suitably adjusted before braking. . As a result, the temperature of each motor that changes due to actual braking when the driver depresses the brake pedal is less likely to exceed the reference temperature, and a reduction in braking performance caused by a temperature change of each motor during braking can be suppressed. In this case, the driving force distribution control is a preparation mode in which the distribution of the driving force of the motors 19 to 22 is suitably set in advance in consideration of the heat generated by each motor during actual braking. In particular, in this driving force distribution control, it is possible to distribute the driving force after estimating the motor loss amount by adding further parameters to the vehicle speed and deceleration.

  In the driving force distribution control, the motor loss amount is estimated on the assumption that the motors 19 to 22 are braked at the maximum deceleration. In this case, since braking at the maximum deceleration is the most severe condition regarding the heat generation of the motor, all of the assumptions can be made by allocating the driving force based on the motor loss amount based on the braking at the maximum deceleration. Therefore, it is reasonable to cope with a decrease in braking performance on the safety side. For example, motor heat generation during braking at a deceleration lower than the maximum deceleration is lower than motor heat generation during braking at the maximum deceleration.

  In the driving force distribution control described above, the motor loss amount of each motor that changes in accordance with the load acting on each of the wheels 11 to 14 is used as the motor heat generation parameter. In this case, the motor loss amount of the motor assigned to each wheel can be easily derived by applying a load change to a pre-stored calculation model. Thereby, it is possible to simply distribute the driving force for the motors 19 to 22 using the motor loss amount of each motor as the motor heat generation parameter.

  The present invention is not limited to the above exemplary embodiment, and various applications and modifications are possible. For example, each of the following embodiments to which the above embodiment is applied can be implemented.

  In the above-described embodiment, the case where the motor loss amount is estimated on the assumption that the motors 19 to 22 are braked at the maximum deceleration has been described. It is also possible to estimate the motor loss amount assuming that braking is performed at a set predetermined deceleration. In this case, braking until the vehicle 10 stops may be assumed, or braking until the vehicle 10 reaches a specified vehicle speed may be assumed.

  Moreover, in the said embodiment, although the form which distributes the driving force of a power running direction was described about distribution of the driving force of the motors 19-22, in this invention, the form which distributes the driving force of a regeneration direction is employ | adopted. You can also.

  In the above embodiment, the motor loss amount is estimated as the motor heat generation parameter. However, in the present invention, in addition to the motor loss amount, another parameter that can indicate the heat generation level of the motor is used as the motor heat generation parameter. Can be used. For example, the motor loss amount is proportional to the motor heat generation amount. Therefore, the motor heat generation amount at the time of virtual braking can be estimated from the product of the motor loss amount calculated in step S103 in FIG. 3 and a predetermined coefficient. In this case, the motor heat generation amount becomes the motor heat generation parameter. In addition, as shown in FIG. 7, the motor loss amount calculated in step S103 in FIG. 3, the current motor temperature detected by the temperature sensor, and external environment parameters (external temperature, vehicle speed, etc.) are stored in advance. By applying to the motor cooling model, it is possible to estimate the motor temperature during virtual braking. In this case, the motor temperature becomes the motor heat generation parameter.

  Alternatively, when the motor heat generation parameter is uniquely determined from the vehicle speed and deceleration of the vehicle 10, the driving force of the motors 19 to 22 can be distributed based on the motor heat generation parameter. For example, when the maximum deceleration and wheel load of the vehicle 10 are simply set in advance, the motor output (motor loss amount) at the time of braking can be uniquely derived only from the vehicle speed in the above step 102. . In this case, the current vehicle speed of the vehicle 10 can be used as a motor heat generation parameter, and the driving force of the motors 19 to 22 can be easily distributed based on the vehicle speed.

  In the above embodiment, the case where the driving force distribution control is executed on the condition that the vehicle 10 is started is described. However, in the present invention, instead of setting the vehicle 10 to be a condition, another condition is satisfied. Driving force distribution control may be executed.

  Moreover, although the case where the above-mentioned drive force distribution control was performed about the four motors 19-22 was described in the said embodiment, in the present invention, the said control is performed about at least 2 motors of the four motors 19-22. can do. In this case, it is preferable that the total driving torque of the four wheels 11 to 14 is set so as not to change before and after the control so as not to give an uncomfortable feeling to the vehicle occupant.

  In the present invention, the number of the plurality of wheels provided in the vehicle and the number of the plurality of motors capable of independently driving or braking the wheels are not particularly limited, and may be appropriately determined according to a design request or the like. Can be changed. In this case, the above-described driving force distribution control can be executed for all or some of the plurality of motors.

  When based on description of said embodiment and various modifications, this invention can take the following each aspects (aspect).

  According to the present invention, “a first step of detecting a vehicle speed of a plurality of motors capable of independently driving or braking a plurality of wheels provided on the vehicle, and detecting the vehicle speed of the vehicle; When the vehicle speed detected in this step is decelerated at a predetermined deceleration by the braking force of the plurality of motors, the driving force or the distribution is distributed to each of the plurality of motors based on the motor heat generation parameter relating to the heat generated in each motor. The aspect | mode (mode 1) including a step of 2 "can be taken.

  According to the present invention, “the wheel control method according to aspect 1, wherein in the second step, the motor heat generation parameter is estimated for each motor, and each of the plurality of motors is determined according to the estimated motor heat generation parameter. A mode (mode 2) in which the driving force is distributed to the wheel control method ”can be adopted.

  According to the present invention, “the wheel control method according to aspect 2, wherein in the second step, it is estimated that the heat generation level is relatively high among the plurality of motors based on the estimated motor heat generation parameter. A wheel control device that distributes the driving force so that the driving force of the motor is less than the driving force of the motor estimated to be at a relatively low heat generation level.

  According to the present invention, “the wheel control method according to aspect 2 or 3, wherein in the second step, the motor heat generation parameter is set when the vehicle is decelerated to a stop at the maximum deceleration as the predetermined deceleration. It is possible to adopt a mode (mode 4) in which the wheel control method is used to estimate the wheel.

  In the present invention, “the wheel control method according to any one of aspects 1 to 4, wherein in the second step, the motor heat generation parameter is changed according to a load acting on each of the plurality of wheels. A wheel control method using the motor loss amount of each motor to be used "(embodiment 5) can be adopted.

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 10a ... Vehicle body, 11 ... Left front wheel, 12 ... Right front wheel, 13 ... Left rear wheel, 14 ... Right rear wheel, 15, 16, 17, 18 ... Suspension mechanism, 19, 20, 21, 22 ... Motor , 23 ... an inverter, 24 ... a power storage device, 25, 26, 27, 28 ... a brake mechanism, 29 ... a brake actuator, 30 ... a control unit, 30a ... a detection unit, 31 ... a first detection sensor, 32 ... a second detection sensor, 33 ... third detection sensor, 40 ... control unit, 41 ... input unit, 42 ... vehicle body behavior control command value calculation unit, 43 ... driving force distribution calculation unit, 44 ... torque calculation unit, 45 ... output unit

Claims (5)

A detection unit that detects a vehicle speed of the vehicle, and a control unit that controls a plurality of motors that can independently drive or brake a plurality of wheels provided in the vehicle,
The control unit is configured to control the plurality of motors based on a motor heat generation parameter related to heat generated in each motor when the vehicle is decelerated at a predetermined deceleration by a braking force of the plurality of motors from the vehicle speed detected by the detection unit. of distributing the driving force respectively to a wheel control equipment,
Wherein the control unit, the motor heat generation parameter estimates for each motor, distributes the driving force to each of the plurality of motors according to the estimated the motor heating parameters, vehicle wheel control device. The wheel control device according to claim 1,
Based on the estimated motor heat generation parameter, the control unit estimates that the driving force of the motor estimated to be at a relatively high heat generation level among the plurality of motors is at a relatively low heat generation level. A wheel control device that distributes the driving force to be less than the driving force.   The wheel control device according to claim 1 or 2,
  The said control part is a wheel control apparatus which estimates the said motor heat generation parameter about the case where the said vehicle decelerates to a stop by the maximum deceleration as the said predetermined deceleration.   The wheel control device according to any one of claims 1 to 3,
  The said control part is a wheel control apparatus which uses the motor loss amount of each motor which changes according to the load which acts on each of these wheels as said motor heat_generation | fever parameter.   Multiple wheels,
  A plurality of motors capable of independently driving or braking each of the plurality of wheels;
  A motor control device for controlling the plurality of motors;
Including
  The said motor control apparatus is a vehicle comprised by the wheel control apparatus as described in any one of Claims 1-4.

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