JP4992370B2 - Vehicle operation control device - Google Patents

Description

  The present invention relates to a motion control device for a vehicle such as an automobile, and more particularly, improved operation when power available in the vehicle (hereinafter referred to as “vehicle power”) is reduced. It relates to the operation of the motion control device.

  Vehicles such as automobiles in recent years require a lot of electric power for traveling and controlling as compared with conventional vehicles. An electric vehicle or a hybrid vehicle consumes electric power for driving the vehicle. In addition, with the advancement of vehicle drive system and braking system electronic control technology, active steering control technology, etc., many electric actuators that consume electric power are mounted regardless of the drive type of the vehicle. . Furthermore, an air conditioner, an audio, a television, etc. mounted on the vehicle also require electric power. However, the power of the vehicle (that is, the amount of electricity that can be charged in the battery) is not always stably or sufficiently available for driving the vehicle, various controls, or operation of the equipment. Therefore, it is necessary to take measures for cases where the power of the vehicle is insufficient or the power supply is abnormal in each part of the vehicle.

For example, as a countermeasure for controlling the braking system when the power of the vehicle is reduced, Patent Document 1 discloses that when the power is reduced in a brake device that performs wheel braking using an electric valve device, It discloses that braking control is performed only on the front wheels of the vehicle, and the electric power consumed by the valve device that operates during braking is reduced. Patent Document 2 proposes to use power from a power source for peripheral devices such as audio when there is an abnormality in power supply from a driving power source such as a braking mechanism.
JP 2003-137085 A JP 2005-117759 A

  Looking at the problem at the time of power reduction of the vehicle about the motion control device that controls the motion of the vehicle by controlling the operation of the drive system and the brake system of the vehicle, the electric actuator or motor of each part of the drive system or the brake system is When the electric power supplied to each actuator decreases, the actuator does not operate normally, which may reduce the effect of vehicle motion control. In the case of an electric vehicle or a hybrid vehicle, the driving force of the vehicle may be reduced due to the consumption of electric power for motion control. Therefore, when considering measures in the vehicle motion control device when the power of the vehicle is reduced, the power consumed for motion control is not consumed without driving in the driving force of the vehicle or other power. It is desirable to reduce and not to impair the effects of the vehicle motion control as much as possible. However, in the past, no example has been proposed in which the countermeasures of the motion control device when the power of the vehicle is reduced are taken into account based on such a concept. For example, as described in Patent Document 1 described above, the method of braking control only for the front wheels when power is reduced can reduce the power consumed by the operation, but VSC (Vehicle Stabilization Control), TRC (Traction Control), etc. It cannot be used for control to independently adjust the braking force of each wheel of the vehicle. Further, as in Patent Document 2, the method of using another power source when the power of one power source is reduced cannot be used when the power of the other power source is also reduced.

  According to the present invention, when the power of the vehicle is lowered, the power consumption of the electric actuator or motor that operates in the motion control is reduced without reducing the effect of the motion control of the vehicle as much as possible. A motion control device is provided.

  In one aspect (first aspect) of the present invention, the vehicle motion control device controls the vehicle motion by controlling the braking / driving force of each wheel of the vehicle by an actuator that is operated by electric power in the vehicle. A motion control device for controlling, comprising means for controlling the operation of the actuator and means for monitoring the power available in the vehicle. Further, the means for controlling the operation of the actuator is such that when the power available in the vehicle is low, the power supplied to the actuator for controlling the motion of the vehicle can be reduced with a lower power supply than when the power usable is high. Configured to start early.

  It should be understood that the configuration of this aspect of the present invention is based on the fact that the power supplied to the actuator is reduced when the available power is high or when the vehicle is powered down. That is, the possibility that the consumed electric power will cut into other electric power used in the vehicle, such as electric power for driving the vehicle, is reduced. However, if the electric power used for the actuator is reduced, the braking / driving force control to be generated on the wheels is delayed or insufficiently adjusted by the braking / driving force control, and the vehicle motion control does not work effectively, or the vehicle It may not be in time for the deterioration of the movement behavior. Therefore, in this aspect of the present invention, when the power of the vehicle decreases, the operation start timing of the actuator is changed so that the braking / driving force control is executed from an early stage. If motion control is started at an early stage, that is, “control is started earlier”, the control action can be achieved even if the control speed of the braking / driving force becomes slow or the control amount is small due to a decrease in the actuator output. Is given to the motion of the vehicle at an early stage, and it is expected that the decrease in the effect of the motion control of the vehicle can be suppressed as much as possible.

  The motion control of the vehicle is usually performed by monitoring a motion state amount indicating a predetermined vehicle motion state, for example, a slip amount or a slip rate of a wheel, and when the predetermined motion state amount deviates from a predetermined range. Be started. Therefore, in the above configuration, when the power of the vehicle is reduced, the operation start timing of the actuator may be advanced by narrowing the predetermined range. In addition, when the vehicle motion control is started when the motion state quantity reaches a predetermined threshold, when the power of the vehicle is reduced, the actuator start timing is reduced by reducing the predetermined threshold. It may be quick.

  In the configuration of one aspect of the present invention described above, the vehicle motion control is performed through adjustment of the braking / driving force on the wheel by the wheel braking device, and therefore the actuator controls the wheel of the vehicle. In the case of including a brake control actuator that adjusts the power, the means for controlling the operation of the actuator can reduce the change gradient of the braking force due to the operation of the brake control actuator when the vehicle motion control is executed when the power of the vehicle is reduced. The power supply of the actuator may be configured to be lower by limiting it to be smaller than when the available power is high. If the change gradient of the braking force is limited, the increase / decrease in the braking force will be delayed, but since the operation of the braking control actuator is started early, there is a certain amount of delay in the increase / decrease in the braking force. Will be compensated. When the wheel braking device is a hydraulic braking device, and the actuator that adjusts the braking force of the wheel is a hydraulic pump that increases the hydraulic pressure and a valve actuator that adjusts the hydraulic pressure of each wheel, Since the power corresponds to the hydraulic pressure supplied to the wheel cylinder of each wheel, the means for controlling the operation of the actuator is that when the power available in the vehicle is low, The power supply power of the actuator may be lowered by limiting the maximum change gradient of the hydraulic pressure due to the operation to a smaller value than when the usable power is high.

  In the configuration of one aspect of the present invention described above, the vehicle motion control adjusts the throttle opening of the engine of the vehicle in addition to the adjustment of the braking / driving force on the wheel by the wheel braking device. When the throttle opening is adjusted using the throttle control actuator, the means for controlling the operation of the actuator is used to adjust the power output of the vehicle. At the time of reduction, only the start of operation of the throttle control actuator for vehicle motion control may be executed earlier than when the available power is high.

  In the case of the configuration in which the operation start time of the actuator is advanced, the operation frequency of the braking / driving force control may be increased. And if braking / driving control is performed, electric power will be consumed reliably. Therefore, when all the actuators related to the control of the braking / driving force are activated at the time of “early control”, although it is reduced, a certain amount of electric power is consumed. In this regard, for example, the brake control actuator is provided with a valve actuator for each hydraulic pump or wheel. Therefore, when all of the brake control actuators are operated, a certain amount of electric power is required. One actuator is usually provided in the throttle valve, and the power consumption of one throttle valve is lower than that of a hydraulic pump or a valve actuator. Therefore, as described above, when there are an actuator for braking control and an actuator for throttle control, when the control is accelerated with low power supply, only the operation of the actuator for throttle control is executed at an early stage. The power consumption at the start of operation may be saved.

  In the above, after the throttle control is advanced, the operation of the brake control actuator may be started when the vehicle motion state needs to adjust the braking / driving force on the wheels. In that case, the power supplied to the actuator for braking control may not be limited. When the throttle control is started first during the vehicle motion control, the wheel speed or the vehicle speed usually decreases, thereby reducing the possibility of further deterioration of the vehicle motion and reducing the vehicle motion. The control amount of the braking / driving force of each wheel required for correction also decreases. Therefore, it is expected that the operation load of the actuator for braking control is reduced and the power consumption of the actuator is also reduced. That is, in the execution of the motion control, during the early stage of the control, only the throttle control is operated to reduce the electric power, and then the operation of the brake control actuator is required. By shortening the throttle control, the power consumption of the braking control actuator can be reduced.

  Further, as described above, the possibility of further deterioration of the vehicle motion is reduced by advancing the start timing of the throttle control, or the control amount of the braking / driving force of each wheel required for correcting the vehicle motion is also reduced. Therefore, when the power of the vehicle decreases, the start of the operation of the brake control actuator after the start of the throttle control is executed at a later time than normal or when the available power is large. It may come to be. For example, when the operation start of the brake control actuator is executed when a predetermined motion state amount deviates from the predetermined range, the predetermined range for starting the operation of the brake control actuator is expanded. Thus, the operation start timing of the brake control actuator may be delayed. If the operation timing of the braking control actuator is delayed, the power consumption can be reduced accordingly.

  In another aspect (second aspect) of the vehicle motion control device of the present invention, as described above, the vehicle motion control is performed by the brake control actuator of the wheel brake device and the throttle opening of the vehicle engine. When the adjustment of the degree is performed by operating the actuator for throttle control, the means for controlling the operation of the actuator is a brake control actuator for controlling the motion of the vehicle when the power available in the vehicle is low The control amount is configured to be smaller than when the available power is high.

  As described above, the brake control actuator requires a certain amount of power when all the actuators are operated, but the throttle control actuator consumes less power than the brake control actuator. Therefore, as described above, the throttle control with low power consumption may be performed as usual, while the control amount of the brake control actuator with high power consumption may be reduced to reduce the power. If the throttle control is executed as usual, the wheel speed or the vehicle speed decreases, and the possibility of the vehicle motion becoming unstable is reduced as described above, and the brake control required for correcting the vehicle motion is used. Since the operation load of the actuator is expected to be reduced, it is expected that the reduction in the effect of the vehicle motion control is reduced while suppressing power consumption. Note that the amount of control of the braking control actuator in the second aspect is reduced when the means for controlling the operation of the actuator executes vehicle motion control when the power available in the vehicle is low. This may be done by limiting the change gradient of the braking force due to the actuation of the braking control actuator at the time smaller than when the available power is high.

  In such a second aspect of the present invention, as one embodiment, for example, the means for controlling the operation of the actuator is used for controlling the movement of the vehicle when the power available in the vehicle is low. The control amount of the throttle control actuator may be configured to be larger than when the available power is high. As already described, the power required for the throttle control actuator is lower than that of the brake control actuator. Therefore, according to this configuration, the vehicle motion state can be controlled by increasing the amount of decrease in vehicle speed while suppressing power consumption. Thus, it becomes possible to make it easier to control in a more stable direction.

  Further, as another embodiment of the above aspect, the vehicle motion control is based on whether the wheel slip amount (for example, the difference between the wheel speed and the vehicle body speed) or the slip ratio (ratio between the slip amount and the vehicle body speed) is predetermined. In the case of feedback control that is started when the threshold value of the vehicle is reached and adjusts the slip amount or the slip ratio of the wheel so as to match the target value, the means for controlling the operation of the actuator is the wheel after the start of vehicle motion control. Braking control actuator by prohibiting the operation of the braking control actuator after the period until the slip amount or slip ratio of the first reaches the predetermined threshold (hereinafter referred to as "initial slip period") Only the control amount may be reduced. When stabilizing the vehicle motion by controlling the slip amount or slip ratio of the wheel by the feedback control as described above, it is important to suppress the deterioration of the initial behavior of the vehicle. In such control, generally, the slip amount or slip ratio of the wheel to be controlled is once relatively brought to the vicinity of the target value, and thereafter, it is relatively stable. Therefore, as described above, during the initial slip period which is important in the control, the actuator is operated as usual, and after the initial slip period when the controlled object is relatively stable, the brake control actuator with high power consumption is consumed. In this case, power saving may be achieved while prohibiting the operation of, and securing the effect of the motion control to some extent.

  By the way, in the vehicle to which the motion control device of the present invention is applied, the throttle valve of the engine has a valve body, and a return spring that exerts a restoring force on the valve body in a direction to return the valve body to a predetermined neutral position. And the throttle control actuator determines the position of the valve body against the restoring force of the return spring, whereby the throttle opening is adjusted. In this case, the means for controlling the operation of the actuator may be configured to preferentially execute the operation of returning the valve body to the neutral position when the throttle control actuator is operated for vehicle motion control. . In the case of a throttle valve equipped with a return spring as described above, when the power of the throttle control actuator is cut off, the valve body automatically returns to a predetermined neutral position (normally the throttle is substantially fully closed). Has been. Therefore, when the direction of increase / decrease control of the throttle opening required in motion control matches the current direction from the valve body position to the neutral position of the valve body, the restoring force of the return spring By allowing the body to return to the neutral position, the power supplied to the throttle control actuator can be reduced. When the valve body returns to the neutral position, the throttle opening is normally reduced, so the wheel speed or the vehicle speed is reduced, and as described above, the possibility that the motion of the vehicle becomes unstable is reduced. In addition, it is expected that the operation load of the actuator for braking control required for correcting the motion of the vehicle is reduced. After the valve body has returned to the neutral position, normal motion control may be executed when further correction of the vehicle motion is required.

  In general, generally speaking, the motion control device of the present invention described above not only uniformly reduces the power supplied to the actuator that is activated when the motion control is performed, but also has the effect of motion control. It can be said that the schedule for operating the actuator is variously changed so as to prevent damage as much as possible. In the change of the operation schedule, what is actually changed is the timing of the start of operation and the magnitude of the supplied power, and the function that can control the braking force for each wheel when the actuator for braking control operates. Since it is held, the braking / driving force is controlled independently for each wheel, giving a braking / driving force difference between the front, rear, left and right wheels, ensuring the effect of motion control such as generating a yaw moment in the desired direction on the vehicle body Is done. When the power is low, the effect of motion control may not be fully demonstrated 100%, but according to the present invention, by selectively modifying the schedule for performing the operation of various actuators, (As it is, if the motion control does not work well, or it is bitten by other necessary power), the effect of the motion control can be maintained to some extent while saving power. Become.

  In some aspects of the present invention described above, as understood from the above description, when the throttle control is incorporated in the vehicle motion control, the throttle control is controlled by the braking device of the wheel. It is executed in preference to. Of course, the throttle control alone does not necessarily stabilize or improve the movement of the vehicle, but first, the throttle control is prioritized and executed, thereby suppressing the wheel speed or the vehicle speed. Thereafter, the operation load of the actuator in the braking / driving force control by the braking device is reduced, and as a result, both the consumption of electric power and the maintenance of the effect of the reduced motion control can be achieved to some extent.

  Other objects and advantages of the present invention will be in part apparent and pointed out hereinafter.

Diagram 1 of the apparatus is a car that the preferred embodiment of the vehicle motion control system of the present invention is mounted is schematically shown. In the figure, a vehicle 10 having left and right front wheels 12FL and 12FR and left and right rear wheels 12RL and 12RR is arranged in a normal manner in each wheel (in the illustrated example, a rear wheel drive vehicle. Only) are equipped with an engine 20 that generates a driving force and a braking device 40 that generates a braking force on each wheel. (Note that although not shown for simplicity, the vehicle 10 is provided with a steering device for controlling the steering angle of the front wheels or the front and rear wheels in the same manner as a normal vehicle.)

  The engine 20 is configured to output drive torque or rotational drive force to the rear wheels 12RL and 12RR via the torque converter 20a, the automatic transmission 20b, the differential gear device 20c, and the like in a normal manner. The output torque of the engine 20 is controlled by adjusting the intake air amount by increasing / decreasing the throttle opening by a throttle valve 24 provided in the intake pipe 22. The engine 20 is provided with an alternator 26 that rotates in conjunction with the crankshaft of the engine 20 to generate power in a normal manner, and charges the battery 28. The throttle valve 24 may adjust the throttle opening in response to the accelerator pedal 14. However, in some embodiments of the present invention described later, the throttle opening may be adjusted for vehicle motion control. If included, the throttle valve is an electronically controlled throttle valve, and is provided with a throttle control actuator that uses the power of the battery 28 to adjust the throttle opening based on a command from the electronic control device 100. The drive device of the vehicle 10 may be an electric type in which an electric motor is used instead of the engine 20 or a hybrid type having both an engine and an electric motor. When the electric motor outputs drive torque, the electric power of the battery 28 is used (the battery is charged by operating the electric motor as a generator).

  The braking device 40 includes a wheel cylinder 42FL, 42FR, 42RL, 42RR equipped to each wheel, a master cylinder 45 and a hydraulic circuit 46 that are operated in response to depression of the brake pedal 44 by the driver in a normal manner. The braking force in each wheel is controlled by adjusting the brake pressure in each wheel cylinder by the operation of the hydraulic circuit 46. FIG. 2 schematically shows the details of the piping configuration of the braking device 40 including the hydraulic circuit 46. Referring to the drawing, a hydraulic circuit 46 controls a brake pressure of a pair of wheel cylinders 42FL and 42FR for the left and right front wheels and a circuit for controlling a brake pressure of the pair of wheel cylinders 42RL and 42RR for the left and right rear wheels. 46R (unless otherwise indicated, the two circuits may have the same piping structure) and in normal operation (when motion control is not being performed), the brake pedal 44 is depressed. In response, the pressure in the master cylinder 44 is supplied to the respective wheel cylinders 42i (i = FL, FR, RL, RR) via the circuits 46F, R.

  On the other hand, when the vehicle motion control is executed, the master cylinder cut valves 50F and 50R directly connected to the master cylinders of the circuits 46F and R are closed based on the command of the electronic control device 100, and the hydraulic pressure is controlled. The hydraulic pumps 52F and 52R provided in the circuit operate to increase the hydraulic pressure between the master cylinder cut valves 50F and 50R and the wheel cylinders 42i of the respective wheels. The wheel cylinder 42i of each wheel is provided with a hydraulic pressure holding valve 54i on the hydraulic pump 52F, R side, and a pressure reducing valve 58i on the buffer reservoir 56F, R side to increase the hydraulic pressure of the wheel cylinder of each wheel. When pressure is applied, the hydraulic pressure holding valve 54i is opened to accept the pressure from the pump, and when pressure is reduced, the pressure reducing valve 58i is opened and operates to release pressure to the reservoir (thus, When maintaining the hydraulic pressure of the wheel cylinder of each wheel, both the valves 54i and 58i are closed.) Thus, by opening and closing the hydraulic pressure holding valve 54i and the pressure reducing valve 58i, the brake pressure of each wheel can be adjusted independently. The operation of each part in the hydraulic circuit when the above-described vehicle motion control is executed, that is, the master cylinder cut valves 50F and 50R are closed, the hydraulic pumps 52F and R are boosted, the hydraulic holding valve 54i and the pressure reducing valve The valve 58i is opened and closed by the electric motor provided in the pump or the valve actuator provided in each valve using the electric power of the battery 28 (the type of the electric motor and the valve actuator is It can be arbitrary.) Therefore, higher power is used when motion control is performed. In this specification, a pump and a valve actuator that are operated by an electric motor are collectively referred to as a braking control actuator.

  Control of the operation of the throttle control actuator or the brake control actuator for vehicle motion control is performed by the electronic control unit 100 as already mentioned. The electronic control unit 100 may include a microcomputer and a drive circuit having a CPU, a ROM, a RAM, and an input / output port device, which are connected to each other by a bidirectional common bus in a normal form. In order to control the movement of the vehicle, the control device 100 receives a throttle opening θth, an accelerator pedal depression amount θa, a brake pedal depression amount θb, a wheel speed Vwi (i = FL) from sensors provided in each part of the vehicle. , FR, RL, RR), detection values such as pressure Pbi (i = FL, FR, RL, RR) in the wheel cylinder of each wheel, engine speed Er, etc. are illustrated as being input, Various detection signals for obtaining various parameters (longitudinal acceleration, yaw rate, etc.) necessary for various controls to be executed in the vehicle of the form may be input. Further, as will be described later, in order to monitor the electric power of the vehicle and control the operation of the alternator, a signal representing the voltage of the battery 28 or the operation state of the alternator is input. As will be appreciated by those skilled in the art, the motion control device of the present invention is realized by the operation of the electronic control device 100.

Operation of the Device In the motion control device of the present invention, the motion control to be executed is performed by adjusting the slip amount or slip ratio of the wheel via the operation control of the braking device 40 and / or the throttle control. It may be any motion control that controls the braking / driving force of the vehicle to correct or stabilize the motion of the vehicle. For example, in the execution of VSC, when correcting or suppressing the oversteer state of the vehicle, the braking force of the turning outer wheel of the vehicle is selectively increased to generate a yaw moment in the turning outward direction of the vehicle, The yaw direction or yaw rate is corrected. On the other hand, when correcting or suppressing the understeer state, a braking force difference is generated between the left and right wheels so that the yaw moment is generated inwardly while turning the vehicle while decelerating the vehicle. Also, in the execution of TRC, the braking / driving force on each wheel is individually controlled so that the slip amount or slip ratio of the drive wheel becomes an appropriate value during acceleration, and in particular, so as not to increase excessively. The

  In the execution of the motion control, the braking / driving force is controlled by adjusting the brake pressure or throttle opening of each wheel independently of the driver's operation of the accelerator pedal or the brake pedal. It becomes. At that time, as understood from the above, the brake control actuator or the throttle control actuator is operated using the electric power of the battery 28. However, if the power of the vehicle is low, sufficient power cannot be supplied to each actuator, or even if it can be supplied, the power to be supplied to other parts or devices of the vehicle. It is possible that you will bite into. Therefore, in the motion control device of the present invention, first, the power of the vehicle is monitored to determine whether or not the power of the vehicle has decreased. When the power of the vehicle is low, as described in the “Disclosure of the Invention” section, the motion control is performed by various modes so that the effect of the motion control is not reduced as much as possible with a power lower than the normal power. The schedule of actuator operation at the time is modified.

  FIG. 3 shows the outline of the control process of the present invention in the form of a flowchart. The control process shown in the figure is repeated at a predetermined cycle during operation of the vehicle or operation of the engine or other drive device. The control process reads various parameters necessary for motion control after the start of control, and schedules the operation of actuators when performing motion control such as VSC and TRC in a known manner, that is, for throttle control and Step 10 for determining a threshold value of a predetermined motion state amount for determining the start of operation of the braking control actuator and an operation amount (control amount) of each actuator, and determination of whether or not the voltage of the vehicle is lowered The step of changing the schedule of the operation of the actuator in the motion control when the vehicle voltage is lowered, and whether or not to operate the actuator according to the schedule of the operation of the actuator at that time A step 40 for making such a determination, and a step 50 for operating the actuator. As will be understood from the figure, the change of the schedule of operation of the actuator is executed only when it is determined that the voltage of the vehicle is lowered, and the operation of the actuator is performed in the schedule of operation of the actuator at that time. Each of the throttle control and the wheel braking control is executed when a predetermined vehicle motion state quantity exceeds a corresponding predetermined threshold value. Therefore, when the change of the actuator operation schedule in step 30 is not executed, the actuator is operated according to the normal motion control mode.

  It should be noted that the determination of whether or not the voltage of the vehicle in step 20 is reduced, that is, the monitoring of the power of the vehicle may be made by detecting the voltage of the battery 28 in the simplest case. This may be done by detecting the amount of power generated per unit time of the alternator. Typically, the alternator is periodically connected to the battery so that the battery voltage is maintained at a predetermined target voltage, and is controlled to charge the battery. The connection time per cycle of the alternator, that is, the duty ratio of the alternator becomes longer as the charge amount of the battery is smaller. Therefore, when the duty ratio is equal to or greater than a predetermined reference value K, the vehicle power is reduced. It may be judged that

  Hereinafter, an example of changing the schedule of operation of several actuators in the embodiment of the motion control device of the present invention will be described.

  In the first embodiment, among the actuators that are operated in the vehicle motion control, the operation schedule of the actuator for braking control is corrected when the power of the vehicle decreases. The configuration of the present embodiment may or may not be executed in the vehicle motion control. However, for the control in which the throttle control is not executed, the engine illustrated in FIG. 1 is used. However, it should be understood that the throttle valve need not be of the electronic control type controlled by the electronic control unit 100.

  In short, in the first embodiment, when the power of the vehicle is lowered, the change gradient (absolute value) of the hydraulic pressure at the time of executing the motion control is limited to be smaller than when the power is not lowered. In this state, the threshold value of the predetermined motion state amount for starting the operation of the brake control actuator is reduced. In operation, first, at step 20, it is determined that the current vehicle power is decreasing, and then at step 30, the map shown in FIG. Ratio k (<1) of the power supplied to the brake control actuator to the maximum power supplied to the brake control actuator when it is determined that the power of the vehicle has not decreased as a function of the ratio Is determined. Then, as a function of the power ratio k, the ratio D (k of the change in the achievable hydraulic pressure at the supply power limited to k times the hydraulic gradient at the normal power (when there is no limit). ) (<1) is determined. The map and slope ratio D (k) for such power ratio may be determined experimentally or theoretically. The gradient ratio D (k) may be determined as a function of the alternator duty ratio.

  Thus, in the later step 50, when the braking control actuator is operated, the supplied power is limited to k times that of the normal time, so that the hydraulic gradient is D (k) times that of the normal time. It will be limited to. The limitation of the supply power and / or the limitation of the hydraulic gradient may be performed by an arbitrary method by the operation of the electronic control device 100. However, when the hydraulic gradient becomes D (k) times that in normal times, the change in braking force also becomes approximately D (k) times. Therefore, when the change of the braking force becomes D (k) times, the threshold value of the motion state amount for determining the operation start of the brake control actuator so that the effect of the motion control at the normal time is compensated, for example, In the case of TRC, the threshold of the wheel slip speed is also corrected to D (k) times that of the normal time, that is, is reduced from the normal threshold value. As described above, when the allowable maximum value of power supplied to the actuator for braking control and the threshold value for starting execution of operation are reduced, the threshold value for motion control is reduced in step 40. The start of execution of the brake control actuator is determined at an early stage, and in step 50, the brake control actuator is operated with a supply power reduced from the normal time. In this operation, it should be understood that the gradient of change in the braking force in the braking control is limited by limiting the power supplied to the braking control actuator, but the braking force of each wheel is limited. Is independently controllable. Accordingly, even if the supplied power is limited, the function of generating a yaw moment in a desired direction by generating a braking force difference between the front, rear, left and right wheels is maintained. This is the same when the brake control actuator is actuated in the following embodiments.

  According to the above embodiment, when the power is reduced, the power supplied to the braking control actuator is saved, so that the change in the braking force for motion control is delayed, but the control itself is executed early. Therefore, the delay in the change in the braking force is compensated (if the control is performed at an early stage, the change in the motion state of the vehicle to be corrected by the control is small, and therefore the control amount of the actuator may be small). It is expected that the suppression of the power consumption of the actuator for braking control and the securing of the effect of motion control are compatible.

  In the second embodiment, when both the throttle control and the braking force control by the wheel braking device are executed in the vehicle motion control, when the power of the vehicle is reduced, the throttle control actuator is mainly used. The schedule of operation is modified. Specifically, if it is determined in step 20 that the current vehicle power is decreasing, a predetermined threshold value of the motion state amount for determining the start of execution of throttle control for motion control, that is, for throttle control. The threshold value for starting the operation of the actuator is reduced below the threshold value determined in step 10. The threshold value may be set to be lower as the duty ratio is longer, that is, as the power reduction is larger, as a function of the alternator duty ratio, for example. Thus, when the electric power of the vehicle is reduced, in step 40, the throttle control is started earlier than the normal time. Note that the threshold value for starting operation of the brake control actuator does not have to be corrected, but conversely, the threshold value may be set higher than normal, and the control start may be later than normal time.

  In operation, when the power of the vehicle is not lowered, execution of throttle control and braking control is determined according to a threshold value for starting execution of normal motion control (steps 10 and 40). Since the threshold value of the throttle control is reduced (step 30), when the vehicle motion state deteriorates, only the throttle control is executed first (steps 40, 50). At this time, in order to increase the effect of the throttle control, the control amount of the throttle control actuator may be increased. The control amount may be increased as the alternator duty ratio is longer (the throttle opening is smaller). In addition, even if the throttle control is executed, the deterioration of the vehicle motion state progresses, and when the threshold value in the normal motion control or a threshold value higher than that is reached, the brake control actuator starts operating only at this stage. Will be.

  According to the above-described embodiment, since the control is only performed by the throttle control, as in the case of the first embodiment, the control is started at an early stage with low power consumption, thereby suppressing the power consumption of the actuator. It is expected not only to ensure the effect of motion control, but also to reduce the operating frequency of the actuator for braking control. As described above, the throttle control actuator and the brake control actuator consume less power in the former, so that further power consumption can be further saved.

  In the third embodiment, when both the throttle control and the braking force control by the wheel braking device are executed in the vehicle motion control, the control amount of the throttle control actuator when the vehicle power is reduced. That is, the actuator operation schedule is modified so that the closing amount of the throttle opening is increased and the control amount of the brake control actuator is reduced. As in the case of the first embodiment, the control amount of the braking control actuator may be reduced by limiting the change gradient of the hydraulic pressure. The closing amount of the throttle opening is a torque value obtained by multiplying the ratio of the braking force when the hydraulic gradient is limited as described above to the braking force when the hydraulic pressure is not limited by the target torque of the engine in normal control, It may be set to be achieved in the engine. Further, the target torque of the engine by the throttle control and the target value of the braking force by the braking control may be multiplied by the reference value K of the duty ratio of the alternator when determining a decrease in the power of the vehicle. (When the target torque of the engine decreases, the control amount of throttle control increases.)

  In operation, in this embodiment, the actuator operation start threshold value is not corrected. Therefore, in step 40, the actuator starts operation at the same time as the normal motion control. At this time, the operation amount of the brake control actuator with high power consumption is reduced, while the operation amount of the throttle control actuator with low power consumption is increased to compensate for the reduction in the operation amount. Thus, according to the present embodiment, it is expected that the suppression of the electric power consumption of the actuator and the securing of the effect of the motion control are compatible without increasing the operation frequency of the actuator.

  In the fourth embodiment, when both the throttle control and the braking force control by the wheel braking device are executed in the vehicle motion control, when the vehicle power decreases, the motion control starts. Actuate the actuator to perform the throttle control and the braking force control in the same manner as in the normal mode, that is, without reducing the power supply, and to prohibit the braking force control after a certain period of time. The schedule of is corrected. In the “Disclosure of the Invention” section, as already mentioned, some of the vehicle motion control is initiated when the wheel slip amount or slip rate reaches a predetermined threshold value. This is performed by feedback control that adjusts the slip ratio to match the target value. As illustrated in FIG. 5, for example, when executing TRC control, a target value of wheel speed is determined in the process of increasing the speed of the entire vehicle, and the actual wheel speed (actual wheel speed) is determined. ) Exceeds a control threshold value determined in accordance with the target wheel speed, control is started. Then, the actual wheel speed converges to the target value while repeatedly increasing and decreasing after the start of control. In the “behavior” of the actual wheel speed, the most important period for control is the “initial slip period until the wheel slip amount or slip rate first reaches a predetermined threshold after the start of vehicle motion control. After this period has elapsed, the value of the wheel speed will change stably substantially along the target value. Therefore, in the present embodiment, as described above, the throttle control and the braking force control are performed only during the initial slip period from the start of the motion control, and after the initial slip period, the braking force control, that is, the braking control actuator is controlled. The operation is prohibited to save the power consumed by the brake control actuator.

  In operation, in this embodiment, the actuator operation start threshold value is not corrected. Therefore, in step 40, the actuator starts operation at the same time as the normal motion control. However, when the initial slip period elapses after the start of the control, in step 40, only the throttle control operation is commanded, and the actuator operation is executed with the braking force control operation prohibited (step 50). Whether or not the initial slip period has elapsed may be determined by an arbitrary method, for example, by tracking a change in wheel speed in the correction of the schedule in step 30. After the initial slip period has elapsed, as in the third embodiment, the control amount of the actuator for throttle control is increased, and the operation schedule of the actuator is modified so that the control amount of the actuator for brake control is reduced. Also good.

  In any of the above Examples 2-4, throttle control is executed at the start of execution of motion control. In this regard, when it is necessary to execute throttle control, such as control for correcting VSC understeer or TRC control, the throttle opening is usually reduced to reduce the vehicle speed or the wheel speed. Therefore, referring to the structure of the throttle valve for adjusting the throttle opening in detail, as schematically illustrated in FIG. 6, in the throttle valve 24, the valve body 70 is disposed in the intake pipe. When the air passage area of the intake pipe is adjusted by rotating around the rotation axis, the angular position of the valve body in the rotational direction is set to a predetermined neutral position by receiving the restoring force of the return spring 72. It is comprised so that it may be positioned. When the throttle opening is changed, a throttle control actuator (usually a motor) 74 rotates the valve body against the restoring force of the return spring 72.

  In such a configuration, if the neutral position of the valve body coincides with the direction of the target position to be changed by the throttle control from the current position of the valve body, it is not necessary to operate the throttle control actuator. The valve body will naturally rotate toward the neutral position. Therefore, in the fifth embodiment, when any one of the second to fourth embodiments is carried out, the throttle opening is achieved in step 30 by referring to the throttle opening from the current position of the valve body. It is determined whether or not the direction to the target position to be matched matches the direction from the current position of the valve body to the neutral position of the valve body, and if so, power is supplied to the throttle control actuator. It is set to stop and allow the valve body to move in the direction toward the neutral position of the valve body. On the other hand, if the valve body is in the neutral position and the throttle opening is too narrow compared to the target value of the throttle opening of the throttle control, an appropriate throttle opening can be achieved by the throttle control actuator. Be controlled.

  When performing the above motion control, the power supply to the throttle control actuator is stopped, and the valve body is allowed to return to the neutral position. However, if the operation threshold of the brake control actuator is increased to delay the start of the operation of the brake control actuator, step 30 can be performed. In this case, it is not necessary to modify the throttle control start threshold.

  Thus, according to the fifth embodiment, it is not necessary to supply power to the actuator for throttle control until the valve body returns to the neutral position by the restoring force of the return spring, so that power consumption can be further saved. .

  Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

  For example, the braking system device 40 of the embodiment is a hydraulic braking device, but even in a type in which a braking force is electromagnetically applied to each wheel, when the power of the vehicle is reduced, as in the above example, By correcting the operation schedule of the actuator used in the braking device, it is possible to suppress a reduction in the effect of the motion control to some extent while saving power consumption. Such a case also belongs to the scope of the present invention. Should be understood.

FIG. 1 is a schematic diagram of a vehicle on which a motion control apparatus according to a preferred embodiment of the present invention is mounted. FIG. 2 is a schematic diagram of a piping configuration of a hydraulic braking device controlled by the motion control device of the present invention. In the figure, the master cylinder cut valves 50F and 50R and the hydraulic pressure holding valve 54i are normally open solenoid valves and consume power when they are closed. The pressure reducing valve 58i is a normally closed solenoid valve, and consumes power when the valve is opened. In FIG. 2, the setting of each valve is in a normal state (a state in which motion control is not performed). FIG. 3 shows, in the form of a flowchart, a control process that incorporates control for correcting the schedule of operation of the actuator when the voltage of the vehicle decreases in the motion control apparatus of the present invention. FIG. 4 is a map for determining the ratio of the allowable maximum value of the power supplied to the brake control actuator when the vehicle power is reduced with respect to the maximum power supplied to the brake control actuator when the vehicle power is not reduced. It is. FIG. 5 is a diagram for explaining changes in wheel speed, control threshold value, and target wheel speed in TRC control. FIG. 6 is a schematic diagram of the structure of an electronically controlled throttle valve. (A) is the figure which looked at the valve body from the front (in the same direction as the air flow of an intake pipe), (B) is sectional drawing which looked at (A) from the side. When the motor 74 is de-energized, the valve body 70 is positioned in the state indicated by the solid line in FIG. When the motor 74 is energized, the motor 74 is rotated as shown by the alternate long and short dash line in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vehicle 12FR-12RL ... Wheel 14 ... Accelerator pedal 20 ... Engine 22 ... Intake pipe 24 ... Throttle valve 26 ... Alternator 28 ... Battery 40 ... Braking device 42FL-42RR ... Wheel cylinder 44 ... Brake pedal 45 ... Master cylinder 46 ... Hydraulic pressure Circuit 50 ... Master cylinder cut valve 52F, R ... Pump 54FL-54RR ... Holding valve 56F, R ... Reservoir 58FL-58RR ... Pressure reducing valve 100 ... Electronic control unit

Claims (5)

A motion control device for controlling a motion of a vehicle by controlling a braking / driving force of each wheel of the vehicle by an actuator that is operated by electric power in the vehicle as a motion control device of the vehicle, wherein the actuator is operated Control means, and means for monitoring the power available in the vehicle , wherein the vehicle motion control is initiated when a predetermined vehicle motion state quantity deviates from a predetermined range. There, when the low power available at the vehicle, means for controlling the operation of the actuator is lower than when the power available for operation of the actuator for the motion control of the vehicle is high vehicle motion control apparatus, characterized in that begins at early by narrowing the且the predetermined range in the supply power.   2. The vehicle motion control apparatus according to claim 1, wherein the actuator includes a braking control actuator for adjusting a braking force of the wheel of the vehicle, and means for controlling the operation of the actuator is used in the vehicle. When the available power is low, the actuator is configured to limit the change gradient of the braking force due to the operation of the brake control actuator when the vehicle motion control is performed to a smaller value than when the usable power is high. A device characterized by lowering the power supplied to the device.   2. The vehicle motion control apparatus according to claim 1, wherein the actuator adjusts the hydraulic pressure of each wheel and the hydraulic pump for increasing the hydraulic pressure in the hydraulic brake apparatus for adjusting the braking force of the wheel of the vehicle. And a means for controlling the operation of the actuator when the electric power available in the vehicle is low, the maximum change gradient of the hydraulic pressure due to the operation of the actuator during the movement control of the vehicle The power supplied to the actuator is reduced by limiting the power to a smaller value than when the usable power is high. A motion control device for controlling a motion of a vehicle by controlling a braking / driving force of each wheel of the vehicle by an actuator that is operated by electric power in the vehicle as a motion control device of the vehicle, wherein the actuator is operated Means for controlling the power available in the vehicle, and means for controlling the operation of the actuator when the power available in the vehicle is low. An apparatus for starting the operation of the actuator for a low-power supply and at an early stage as compared to when the available power is high,
The actuator includes a braking control actuator that adjusts a braking force of the wheel of the vehicle, and a throttle control actuator that controls a throttle opening degree of the engine of the vehicle, and the means for controlling the operation of the actuator includes: When the available power in the vehicle is low, only the start of operation of the throttle control actuator for motion control of the vehicle is executed earlier than when the usable power is high. apparatus. The vehicle motion control apparatus according to claim 4 , wherein the throttle valve of the engine includes a valve body and a return spring that exerts a restoring force on the valve body in a direction to return the valve body to a predetermined neutral position. The throttle control actuator is a throttle valve that moves the position of the valve body against the restoring force of the return spring and thereby adjusts the throttle opening, and means for controlling the operation of the actuator includes: An apparatus for preferentially executing the operation of returning the valve body to the neutral position when the throttle control actuator is operated for motion control of the vehicle.

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