JP3370983B2 - Drive control device for electric vehicle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a wheel system in which two wheels are supported by a tandem wheel type suspension.
The present invention relates to a drive control device for an electric vehicle that has more than one drive wheel, is mounted on an electric vehicle that uses an in-wheel drive for each drive wheel, and controls each motor so as to improve running stability during slip. .

As shown in FIG. 7, an electric vehicle is a vehicle that can travel using only the driving force of the electric motor 101.
As a power source to be supplied to the electric motor 101, one using a secondary battery (battery) is called an electric vehicle A in a narrow sense, one using an engine generator is called a series hybrid vehicle B, and one using a fuel cell is called a fuel cell vehicle C. I will decide. In FIG. 7, 102 is a wheel, 103 is a controller, 104 is a secondary battery, 201 is an engine, 2
Reference numeral 02 is a generator, 301 is a hydrogen supply unit, and 302 is a fuel cell.

As described above, an electric vehicle is a vehicle that can travel using only the driving force of a rotary electric motor, and a secondary battery, a fuel cell, an internal combustion engine is used as a power source to supply the electric motor. It is defined as a car that uses a generator that uses a solar cell, a solar cell, etc., and a combination of these. However, in the following description, an electric vehicle using only a secondary battery is taken into consideration, but a vehicle using a fuel cell, an internal combustion engine generator, or a solar cell as a power source is naturally included.

[0004]

2. Description of the Related Art The development of electric vehicles has become an urgent task as a deciding factor for preventing air pollution due to motorization. Recognizing that conservation of the natural environment is a major goal of the 21st century, the inventor of the present application has started its research from the 1980s and is making good results.

For example, in an electric vehicle in which electric energy stored in a battery is supplied to a rotary electric motor for traveling, and wheels are driven by the rotary electric motor, the floor structure of the automobile is The floor structure is made up of a plurality of axially hollow frames to enhance the rigidity of the floor structure, and the battery is housed in the floor structure. At least a part of the rotary electric motor is a wheel of a wheel. The rotary electric motor and the floor structure are housed in a portion, and are connected via a suspension device (see Japanese Patent Laid-Open No. 10-278596).

Further, in each drive wheel independent drive type electric vehicle equipped with an in-wheel drive in which motors are incorporated in all four wheels, a situation of occurrence of slip or tendency of each drive wheel, particularly slip or tendency thereof, is exhibited. Driving wheels (slip wheels) and other driving wheels (non-slip wheels)
By determining the command value of the output torque according to the position and the number of the wheels, 4WD by the motor torque control is realized, and according to the positions and the number of the slip wheels and the non-slip wheels, the TRC ( Tru
action control) or ABS (Antil)
Japanese Patent Laid-Open Publication No. 10-295004 discloses a technique in which a motor torque control realizes a control corresponding to an "Ok Break System".

[0007]

However, the above-mentioned technique is intended for four-wheeled vehicles, and the supporting load for each wheel is relatively large. The supporting load of each vehicle wheel can be reduced, if TRC or ABS control commensurate therewith, can reduce the slippage and improve the running stability.

In view of the above situation, the present invention provides an in-wheel drive having a wheel system supported by a tandem wheel suspension and adopting a control capable of improving running stability, and incorporating motors in all the wheels. It is an object of the present invention to provide a drive control device for an electric vehicle that can independently drive the provided drive wheels.

[0009]

In order to achieve the above object, the present invention provides [1] a wheel system in which drive wheels each of which is rotationally driven by output torque of a corresponding motor are supported by a tandem wheel suspension. It is installed in an electric vehicle that has eight, including the tandem wheel type suspension system, and the wheel load is reduced by the wheel system supported by the tandem wheel suspension.
Drive controller that commands output torque value for each motor
Is supported by the tandem wheel suspension.
Regarding the wheel system you have, whether or not slip has occurred
Whether the two wheels of this wheel system are locked
Kaniyori, a slip ring detection means for discriminating the slip ring and a non-slip wheels, the non-slip-wheel or non-slip car
When there are at least one wheel system on the left side and one on the right side of the vehicle body, adjustment is made so that no new yaw moment acts on the vehicle body, and the motors of the motors and wheel systems are adjusted.
Characterized in that it comprises a 8-wheel drive control means for commanding the output torque value to data.

[2] It is mounted on an electric vehicle having eight drive wheels, each of which is driven to rotate by the output torque of a corresponding motor, including a wheel system supported by a tandem wheel suspension, and supported by the tandem wheel suspension. while reducing the support load of the wheel by a wheel system that is, a drive control device for commanding an output torque value for each motor, the tandem wheel suspend
Slippage occurs for wheel systems supported by
Both wheels of this wheel system lock both wheels
A slip wheel detecting means for discriminating between a slip wheel and a non-slip wheel depending on whether or not
When the slip wheel system no one in and right when no one on the left side of the vehicle body, after applying an adjustment in accordance with the slip state of the slip ring, the output torque to said motor of each motor and wheel system TRC / ABS equivalent control means for instructing a value.

In the present invention, if at least one non-slip wheel is provided on each of the left side and the right side of the vehicle body, output torque control of each motor (for example, the output torque of the motor corresponding to the slip wheel is cut, and only the non-slip wheel is provided). Control the output torque of each motor so that the required acceleration / deceleration can be realized.
8W by preventing the generation of yaw moment
Achieving D.

As a result, highly reliable running stability control capable of quickly recovering running stability at the time of slip is realized.

Further, since the TRC / ABS equivalent control is realized by adjusting the command relating to the output torque value, there is no need to operate the pressure of the braking fluid, for example, the hydraulic pressure, and therefore, there is no need to provide a valve, a pump or the like for that purpose. The running stability can be quickly restored when slipping. Also, depending on the position and number of slip wheels and non-slip wheels, TRC / ABS
Since appropriate control is activated, TRC / A can be used under appropriate circumstances.
The BS-equivalent control operates, so that highly reliable running stability control is realized.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(1) System Configuration FIG. 1 shows a schematic configuration of an eight-wheel drive vehicle showing an embodiment of the present invention, and FIG. 2 shows a system configuration of an electric vehicle showing an embodiment of the present invention.

In the present invention, the front and rear wheel systems need not be wheel systems supported by the tandem wheel suspension, but only the front or rear wheel system are wheel systems supported by the tandem wheel suspension. Good.

The electric vehicle shown in these figures is an in-wheel motor type eight-wheel drive electric vehicle. That is, the center frame 71 and the side frame 72 are provided in the lower part of the vehicle body 70, and the wheel system supported by the tandem wheel suspension is provided.
It is an electric vehicle with each drive wheel independent drive equipped with an in-wheel drive that incorporates a motor into each), and it is possible to reduce the supporting load of each wheel, and TRC or ABS suitable for it.
Control is performed to reduce slippage and improve running stability.

The wheel system supported by the tandem wheel suspension includes a right front front wheel RFF40 and a right front rear wheel R.
FR41, left front front wheel LFF42, left front rear wheel LFR4
3, the right rear front wheel RRF44, the right rear rear wheel RRR45, the left rear front wheel LRF46 and the left rear rear wheel LRR47, the motors 30, 31, 32, 33, 34, 35, 3 respectively.
6 and 37 are incorporated.

The battery 6 is a drive power supply source to each motor, and its output is to the motors 30 and 31 via the inverters 10 and 10 ', to the motors 32 and 33 via the inverters 11 and 11', and to the inverters 12 and 12. Power is supplied to the motors 34 and 35 via 12 'and to the motors 36 and 37 via inverters 13 and 13', respectively. In addition,
Each inverter 10 to 13 'is provided for each wheel.

The inverters 10 and 10 'are connected to the vehicle controller 1
Under the control of the motor control unit 2 which is controlled in accordance with the above, the output of the battery 6 is converted into electric power (converted into three-phase alternating current in this figure) and supplied to the motors 30 and 31 for torque control or speed control. . Inverters 11, 11 ', 12, 1
2'and 13, 13 'operate similarly.

The motor controller 2 responds to the torque command TRF, the motor controller 3 responds to the torque command TLF, the motor controller 4 responds to the torque command TRR, and the motor controller 5 responds to the torque command TLR. , And the corresponding inverters are controlled to control the torque of the motor. All torque commands given to the motor control units 2, 3, 4 and 5 are output from the vehicle control unit 1. The control of the inverter for each motor is performed based on the detected value of each phase current of the motor obtained from a current sensor (not shown) or the estimated value of each phase current of the motor obtained from the rotor angular position and the like.

The vehicle control unit 1 is composed of an electronic control unit (ECU) that controls the output torque of each motor, monitors and controls the state of each on-vehicle component, notifies the vehicle occupant of the vehicle state, and other functions. Have some software. The vehicle control unit 1 includes wheel speed sensors 50, 51, 5
2, 53, 54, 55, 56 and 57, brake sensor 14, steering angle sensor 15, shift position switch 1
6 and the detection output of the accelerator sensor 17 are input.

A wheel speed sensor (for example, a resolver) provided for each wheel is a wheel speed VRF of each wheel.
F, VRFR, VLFF, VLFR, VRRF, VRR
A signal indicating R, VLRF, and VLRR (for example, a pulse signal for each minute angular position displacement) is generated and supplied to the vehicle control unit 1.

The accelerator sensor 17 gives a signal indicating the amount of depression of an accelerator pedal (not shown), the brake sensor 14 gives a signal showing the amount of depression of the brake pedal 20, and the shift position switch 16 has a shift lever (not shown). Of the input range (and the shift lever position within the range in the engine braking range, etc.), that is, a signal indicating the shift position.
The steering angle sensor 15 generates a signal indicating the result of steering angle detection of the steering wheel, for example, a signal indicating the steering angle δt.

Outputs of these sensors are converted into data in a format processable by the vehicle control unit 1 when input to the vehicle control unit 1. The vehicle control unit 1
The converted data is used to determine the torque command, switch the control method, and the like.

In the present invention, a tandem type braking system for braking each of the front, rear, left and right wheels by both hydraulic pressure and regeneration is used in accordance with a design policy for ensuring safety. That is, when the brake pedal 20 is depressed, the hydraulic pressure generated in the master cylinder 21 in response to the depression is applied to the brake wheel BW via the wheel cylinders provided in the respective wheels.
60, BW61, BW62, BW63, BW64, BW
65, BW66 and BW67, and braking torque is applied to the wheels. On the other hand, the braking force detected using the brake sensor 14 (the hydraulic pressure of the master cylinder 21)
Torque command TR that the vehicle control unit 1 takes to regenerate according to FB
Generate F, TLF, TRR and TLR.

Therefore, the braking force distribution in the vehicle shown in FIG. 2 is a distribution in which both the hydraulic pressure regeneration increases as the braking force FB increases.

As described above, since the hydraulic system and the regenerative system are separated after the brake sensor 14, even if one of the hydraulic system and the regenerative system malfunctions, the other can evacuate the vehicle. Furthermore, since the hydraulic system is not provided with a pump and the valve is only provided with a proportioning valve for distributing hydraulic braking force to the front and rear, the system configuration is simplified.

One of the reasons why it is not necessary to provide a pump in the hydraulic system and the number of valves on the hydraulic system can be minimized is as described later.
This is a characteristic configuration of the present embodiment in which the traveling stability control is performed by utilizing the control of the output torque of the R, FL, the motor RR, and the motor RL.

(2) The control function of the vehicle control unit in this embodiment will be described with reference to the flowchart of FIG.

The vehicle controller 1 first detects the vehicle speed VS (step S1).

Although various procedures can be adopted as the procedure for detecting the vehicle body speed VS, it is preferable to adopt the procedure shown in FIG. 4, for example. In FIG. 4, the vehicle control unit 1 first reads the detected value V from the vehicle body speed sensor SM as one set for each two wheels having a tandem structure (step S30) and calculates the wheel angular acceleration dω / dt thereof. (Step S31). As a calculation formula of the wheel angular acceleration, the following formula dω / dt ← (1 / R) · dV / dt can be used. Where R is the wheel radius,
V and ω are the wheel speed and the wheel angular speed applied to the wheel whose wheel angular acceleration is currently being calculated. Vehicle control unit 1
Is whether the absolute value of the wheel angular acceleration dω / dt thus obtained exceeds a predetermined threshold value, and the above-mentioned one set is compared, and the wheel angular acceleration dω / dt of both two wheels (all wheels) of one set is compared. If the absolute value of exceeds the threshold value, it is judged as slip NS. If one wheel in one set exceeds the threshold value and the other wheel does not exceed the threshold value, it is judged as non-slip and the threshold value is exceeded. The non-slip wheel speed V is held as the wheel speed of the set, and when the absolute value of the wheel angular acceleration dω / dt does not exceed the threshold value for both of the two wheels in one set (all wheels), it is determined as non-slip. The large wheel speed is held as the wheel speed of the set (step S32).

When it is determined that the one set of wheels is not slipping, the wheel speed V of that wheel is added to the variable VS (step S33). Conversely, when it is determined that the one set of wheels is slipping, the angular acceleration dω / dt
If the absolute value of is greater than a predetermined threshold value, it can be considered that a slip or a tendency thereof has occurred for that wheel, and therefore a wheel that can be considered as a slip or a tendency thereof (slip wheel) NS, which is a variable for counting the number of (1), is incremented by 1 (step S34).

Then, the vehicle control section 1 proceeds to step S33.
Alternatively, after step S34 is executed, the positions of the wheels and the wheel speed V of the set are stored in a built-in memory or the like (step S35). The vehicle control unit 1 executes the procedure of steps S31 to S35 for all drive wheels including all tandem-structured wheels (step S).
36).

The vehicle control unit 1 determines whether all the drive wheels are slip wheels or non-slip wheels in this way, and then determines whether the number NS of slip wheels is equal to 4, that is, all drive wheels. It is determined whether or not slips (step S37). Normally, all the drive wheels do not slip or show the tendency at the same time, so the vehicle control unit 1 divides the value accumulated in VS by the repeated execution of step S33 by 4-NS, that is, the number of non-slip wheels. By doing so, the vehicle speed VS is calculated (step S38).

On the contrary, when NS = 4 holds,
By using the information stored when step S35 was executed in the past, it is searched which wheel is the drive wheel that finally started to slip (step S39). The vehicle control unit 1 uses, as the vehicle body speed VS, the value of the wheel speed V that the drive wheels found as a result of this search, that is, the wheel that started to slip lastly, had just before starting to slip ( Step S40).

As described above, in the present embodiment, as a general rule, the vehicle body speed VS can be determined relatively accurately by obtaining the vehicle body speed VS only from the wheel speeds of the non-slip wheels. The torque command value tentatively determined by the procedure described above is made appropriate.

Further, because of the tandem suspension structure, it is extremely rare that all eight wheels slip or exhibit the tendency, but even at that time, the last wheel that started to slip Since the vehicle body speed VS is the average of the wheel speeds that have been within a predetermined time from immediately before the start of slipping, relatively reliable vehicle body speed information can be used for provisionally determining the torque command value. After the execution of step S38 or step S40, the operation of the vehicle control unit 1 returns to step S2 in FIG.

In FIG. 3, after detecting the vehicle speed VS, first, in order to determine the steering state, it is determined whether the absolute value of the steering angle δt is equal to or greater than a predetermined threshold value ( Step S2). When the steering angle is larger than the threshold value and there is no slip (step S12), the vehicle control unit 1 executes the target yaw rate adaptation control and the target slip angle adaptation control (for example, slip angle 0 control) (step S).
3).

For example, when the absolute value of the steering angle δt detected by the steering angle sensor 15 is equal to or greater than a predetermined threshold value, that is, when it is determined that the vehicle operator is steering, the vehicle body accompanying the steering In order to prevent or suppress the occurrence of running instability, the target yaw rate adaptive control or the target slip angle adaptive control is executed.

FIG. 5 shows an example of the procedure of the target yaw rate adaptation control or the target slip angle adaptation control.

In the flow shown in FIG. 5, the vehicle control unit 1 first determines the accelerator on / off state based on the output of the accelerator sensor 17, the shift position given by the shift position switch 16, and the steering angle sensor 15.
From the steering angle δt and d that can be calculated based on this
Coupling coefficient group based on δt / dt etc. (formula based on experience)
Is selected (step S50). The vehicle control unit 1
Further, the wheel acceleration dV / dt is calculated for each wheel of the tandem suspension structure, and based on this, the road surface friction coefficient μ
(Equation based on experience) is calculated (step S51).

The vehicle control unit 1 determines the correction coefficient k for each wheel based on the road surface friction coefficient μ and the steering angle δt and using the combination coefficient group selected in step S50 (step S52). When the accelerator is on (step S53), the vehicle control unit 1 determines the wheel speed V and the accelerator opening VA.
And a torque command for each wheel from the power running torque map based on the shift position (step S54) and when the accelerator is off (step S53) from the regenerative torque map based on the wheel speed V, the braking force FB and the shift position. Is provisionally confirmed (step S55). The power running torque map is a map showing the rotation speed torque characteristics of the motor in both positive rotation speed and torque regions, and the regenerative torque map is the map showing the rotation speed torque characteristics of the motor in positive rotation speed and negative torque regions. It is, and it asks by experience.

The vehicle control unit 1 adds the torque command temporarily determined in step S54 or step S55 to step S5.
The torque command is determined by multiplying the correction coefficient k determined in 2 (step S56), and the determined torque command is output to the corresponding motor control unit (step S57).

Therefore, depending on the value of the coupling coefficient group to be selected in step S50 and the method of setting the correction coefficient k in step S52, the torque when executing the target yaw rate adaptive control or the target slip angle adaptive control is executed. The range that the command can take may be a value that belongs to the regenerative region even when the accelerator is on, or a value that belongs to the power running region even when the accelerator is off. By performing such control, the running stability of the vehicle body during steering is improved in the present embodiment.

Regarding the target yaw rate adaptation control and the target slip angle adaptation control, Japanese Patent Application Laid-Open No. 10-210604.
See the disclosure of the publication. Further, instead of the target yaw rate adaptive control and the target slip angle adaptive control, a method of executing the traveling stability control using a plurality of state quantities indicating the motion state of the vehicle including the yaw rate acting on the vehicle body may be adopted. Good.

Regarding this technique, Japanese Patent Laid-Open No. 10-271
See Japanese Patent No. 613. After the target yaw rate adaptation control and the target slip angle adaptation control are completed, the operation of the vehicle control unit 1 returns to FIG.

The vehicle controller 1 returns to step S1 and repeats the operation. Further, in step S2 executed after detecting the vehicle body speed VS, when it is recognized that it is not necessary to execute the target yaw rate adaptation control or the target slip angle adaptation control, that is, when the absolute value of the steering angle is smaller than the threshold value, In principle, the control unit 1 executes the procedure related to the 8WD control (step S6). When starting the 8WD control (step S6), the vehicle control unit 1 first determines the vehicle speed V
The number of slip wheels corresponding to one set of wheels in the tandem suspension structure detected by the S detection procedure (see
Number of packets ) The judgment / classification process regarding NS is executed.

That is, the number of detected slip wheels N
When S is equal to 4, that is, when all driving wheels are slipping (step S7), the number NS of slip wheels is
Is equal to 3, that is, when there is only one drive wheel (one set) of the tandem suspension structure that does not show the slip or the tendency (step S8), the operation of the vehicle control unit 1 is not the 8WD control (step S6). T
The control shifts to the RC / ABS equivalent control (step S9).

Further, even when the number NS of slip wheels is equal to 2, that is, even when there are two drive wheels of the tandem suspension structure which do not show slip or the tendency (step S10), it is detected. When the slip wheels are both left wheels or both right wheels (step S11), the control shifts to TRC / ABS equivalent control (step S9).

Further, even when it is determined in step S2 that the target yaw rate adaptive control or the target slip angle adaptive control is required, the number NS of slip wheels is non-zero, that is, When it is recognized that the drive wheels of the tandem suspension structure have slipped or tend to slip (step S1
2) Also, the control shifts to the TRC / ABS equivalent control (step S9).

Here, an example of the procedure of TRC / ABS equivalent control is shown in FIG.

In executing the TRC / ABS equivalent control, the vehicle control unit 1 first sets the wheel speed V of each wheel to a high / high level.
A coupling coefficient group, a control constant group, or the like is selected according to low, accelerator on / off, or the like (step S60). The coupling coefficient group mentioned here is a set of coefficients used for determining a threshold value group used for angular acceleration determination described later, and the control constant group is a set of constants used when determining the feedback torque. .

When the accelerator is on (step S61), the vehicle controller 1 determines the wheel speed V and the accelerator opening V.
From the power running torque map according to A and the shift position (step S62), when the accelerator is off (step S62), from the regenerative torque map according to the wheel speed V, the braking force FB and the shift position (step S62).
63), the torque command is provisionally determined.

Further, when the accelerator is on (step S62), the vehicle control unit 1 is based on the accelerator opening degree VA and the coupling coefficient group selected in step S60 (step S64), and the accelerator is off. If so (step S62), based on the braking force FB and the coupling coefficient group selected in step S60 (step S65),
Determine a threshold group.

The vehicle control unit 1 classifies the angular acceleration dω / dt of each wheel with reference to the threshold value group determined in step S64 or step S65 (step S66). The vehicle control unit 1 determines the feedback torque using different arithmetic expressions and the like according to the classification result.

For example, when the wheel angular acceleration dω / dt belongs to the first range, the feedback torque determination process by the first calculation formula is performed (step S67-1), and when it belongs to the second range, the second calculation formula is used. Based on the feedback torque determination processing (step S67-2), if it belongs to the third range, the feedback torque determination processing by the third calculation formula (step S67-3), ... If it belongs to the nth range, the nth calculation The feedback torque determination process based on the equation is performed (step S67-n), and the feedback torque is determined for each wheel by an arithmetic expression according to the range to which the rotational angular acceleration dω / dt belongs.

Further, steps S67-1, S67-2,
S67-3. ... The constants in the arithmetic expression related to S67-n are
The value is applied to the control constant group selected in step S60.

The vehicle control unit 1 determines the torque command value by subtracting the feedback torque thus determined from the torque command value provisionally determined in step S62 or step S63 (step S68), and the determined torque is determined. The command value is output to the corresponding motor control unit (step S69).

By adopting such a procedure,
The torque acting on each drive wheel can be appropriately changed, and a function equivalent to TRC / ABS control in a conventional engine vehicle can be realized. In addition, TRC / A
For the BS-equivalent control, refer to the disclosures of JP-A-8-182119 and JP-A-10-210604. After completing the procedure shown in FIG. 6, the operation of the vehicle control unit 1 proceeds to step S4 shown in FIG.

The vehicle control unit 1 determines the transition conditions to the target yaw rate adaptation control or the target slip angle adaptation control and TRC / A.
When none of the conditions for shifting to BS equivalent control are met,
That is, the absolute value of the steering angle δt does not exceed the threshold value,
Number of slip wheels with tandem suspension structure NS
When (the number of sets) is 2 or less and neither the left two wheels nor the right two wheels are slip wheels, the procedure according to the 8WD control step S6 is executed.

At this time, the vehicle control unit 1 first determines whether or not the number NS of slip wheels is 1 (step S13). Since NS = 0 on a normal road, the operation of the vehicle control unit 1 proceeds to step S14 and step S15. In step S14, the vehicle control unit 1
Determines all drive wheels of the tandem suspension structure as distribution wheels. The distribution wheel here is a drive wheel that actually distributes the torque output. In step S15,
The vehicle control unit 1 sets the specific gravity of torque output distribution to each distribution wheel to a normal value.

For example, the distribution specific gravity = 1 is set for all the drive wheels. However, the specific gravity of this distribution may be changed according to the vehicle weight, or may be a predetermined specific gravity that differs between the front and rear wheels depending on the structure of the vehicle body.

On the contrary, when it is judged that NS = 1 in step S13, or when TRC /
When it is determined that the condition for shifting to the ABS equivalent control is not satisfied, the wheels other than the slip wheels of the vehicle control unit 1 are determined as the distribution wheels (step S16).

Further, when the torque is actually output, the distribution specific gravity for each vehicle is adjusted so that the moment in the yaw direction centered on the center of gravity of the vehicle does not newly act on the vehicle body, that is, the left and right are balanced. Yes (step S17).

For example, the driving wheels not selected as the distribution wheels in step S16, that is, the slip wheels, have a distribution specific gravity of 0 so that no torque command is given, and the left or right non-slip wheels to which the slip wheels belong. To the distribution specific gravity, the distribution specific gravity corresponding to the torque output that should have been distributed to the slip wheels if the vehicle is not slipping is added.

After executing step S15 or step S17, the vehicle control unit 1 determines from the power running torque map according to the vehicle speed VS, the accelerator opening VA and the shift position if the accelerator is on (step S18) (step S19). ), If the accelerator is off (step S1)
8) The torque command is provisionally determined from the regenerative torque map according to the vehicle speed VS, the braking force FB, and the shift position (step S20). After executing step S19 or step S20, the vehicle control unit 1 adjusts the torque command value temporarily determined in step S19 or step S20 according to the distribution specific gravity set or adjusted in advance in step S15 or step S17. (For example, the distribution specific gravity is multiplied), and thereby the torque command value for each wheel is determined (step S21).

The vehicle control unit 1 outputs each torque command value determined in step S21 to the corresponding motor control unit (step S22), and then shifts to step S4.

Therefore, in this embodiment, the control state is switched according to the slip state of each wheel of the tandem suspension structure. First, assuming that the two wheels of the tandem suspension structure are one unit, when only one of the four wheels is slipping, that is, when NS = 1,
If the slip wheel is not slipping, the torque command that should have been given to the slip wheel is output to the other drive wheel on the same side as the slip wheel.

Similarly, when NS = 2 and one slip wheel exists on each of the left and right sides, a torque command is realized by the non-slip wheels that remain on the left and right sides, respectively. Further, when NS = 2 and both slip wheels are on the left side (or right side), the TRC / ABS equivalent control is executed. Furthermore, when NS = 3, NS =
When it is 4, the TRC / ABS equivalent control is executed again.

As described above, according to the present invention, the vehicle control unit 1 controls each motor output mode and each wheel according to the occurrence state of slip or the tendency of each wheel, particularly the number and position of slip wheels. Since the torque distribution specific gravity is switched or changed, it is possible to realize suitable 8WD control and TRC / ABS equivalent control in an in-wheel motor type eight-wheel drive electric vehicle, and maintain and improve running stability.

The present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

[0073]

As described above in detail, according to the present invention, the following effects can be obtained.

(A) Each drive wheel having a wheel system supported by a tandem wheel suspension, which employs a control capable of improving running stability, and equipped with an in-wheel drive in which motors are incorporated in all eight wheels It is possible to provide an electric vehicle that can be driven independently.

(B) Improving running stability in each drive wheel independent drive type electric vehicle having a wheel system supported by a tandem wheel suspension and equipped with an in-wheel drive in which motors are incorporated in all eight wheels since the control that can be employed, possible to reduce the bearing load of each vehicle wheel, at least one so can TRC or ABS control commensurate therewith, can reduce the slippage, or, non-slip wheels on the left and right of the vehicle body Each time, the output torque value is commanded to each motor after adjusting so that a new yaw moment does not act on the vehicle body.
It is possible to realize 8WD while preventing the occurrence of moment in the yaw direction, and realize highly reliable running stability control during slip.

(C) In each driving wheel independent drive type electric vehicle having a wheel system supported by a tandem wheel type suspension and equipped with an in-wheel type drive in which motors are incorporated into all eight wheels, running stability is improved. Since the control that can be improved is adopted, slip etc. can be reduced and running stability can be improved. Also, when there are no non-slip wheels on the left side of the vehicle and there are no non-slip wheels on the right side, the slip wheels slip. Since the output torque value is commanded to each motor after adjusting according to the state, TRC / ABS
Equivalent control without a member for pressure operation of the braking fluid 8
Since WD can be realized and TRC / ABS equivalent control operates under appropriate conditions, highly reliable running stability control at the time of slip can be realized.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an eight-wheel drive vehicle showing an embodiment of the present invention.

FIG. 2 is a system configuration diagram of an electric vehicle showing an embodiment of the present invention.

FIG. 3 is a flowchart showing an operation procedure of a vehicle control unit.

FIG. 4 is a flowchart showing vehicle body speed detection steps.

FIG. 5 is a flowchart showing target yaw rate (slip angle) matching control steps.

FIG. 6 is a flowchart showing TRC / ABS control steps.

FIG. 7 is a diagram showing a basic configuration of an electric power vehicle.

[Explanation of symbols]

1 Vehicle Control Unit (CPU) 2, 3, 4, 5 Motor Control Unit (CPU) 6 Battery 10, 10 ', 11, 11', 12, 12 ', 13, 1
3 'inverter 14 brake sensor 15 steering angle sensor 16 shift position switch 17 accelerator sensor 20 brake pedal 21 Master cylinder 30,31,32,33,34,35,36,37
Motor 40 Right front front wheel (RFF) 41 Right front rear wheel (RFR) 42 Left front front wheel (LFF) 43 Left front rear wheel (LFR) 44 Right rear front wheel (RRF) 45 Right rear rear wheel (RRR) 46 Left rear front wheel (LRF) 47 Left rear rear wheel (LRR) 50, 51, 52, 53, 54, 55, 56, 57
Wheel speed sensor (SM) 60, 61, 62, 63, 64, 65, 66, 67
Brake wheel (BW) VRFR, VRFF, VLFF, VLFR, VRRF,
VRRR, VLRR, VLRF Wheel speed TRF, TLF, TRR, TLR Torque command 70 Vehicle body 71 Center frame 72 Side frame

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60L 9/18 B60K 1/02 B60K 7/00

Claims (2)

(57) [Claims] 1. An electric vehicle having eight drive wheels including a wheel system supported by a tandem wheel suspension, each of which is driven to rotate by an output torque of a corresponding motor, and is supported by the tandem wheel suspension. A drive control device for instructing an output torque value to each motor in a state in which a wheel support load is reduced by a wheel system that: (a) is supported by the tandem wheel suspension.
For wheel systems that have
The disconnection depends on whether or not both wheels of the wheel system are locked.
Ri, a slip ring detection means for discriminating the slip ring and a non-slip wheels, (b) when said non-slip-wheel or non-slip wheel system is by at least one on the left and right of the vehicle body, a new yaw to the vehicle body in terms of the direction moment is subjected to adjusted so as not to act, electrical, characterized in that it comprises a 8-wheel drive control means for commanding <br/> force torque value output by to said motor of each motor and wheel system Vehicle drive control device. 2. An electric vehicle having eight drive wheels including a wheel system supported by a tandem wheel suspension, each of which is driven to rotate by the output torque of a corresponding motor, and is supported by the tandem wheel suspension. that in a state of reduced support load of the wheel by a wheel system, a drive control device for commanding an output torque value for each motor, supported by (a) the tandem wheel suspension
For wheel systems that have
The disconnection depends on whether or not both wheels of the wheel system are locked.
Ri and slip ring detection means for discriminating the slip ring and a non-slip wheels, if (b) the non-slip-wheel or non-slip wheel system no one in and right when no one on the left side of the vehicle body, the slip after applying the adjusted depending on the slipping condition of wheels, the drive control apparatus for an electric vehicle, characterized in that it comprises a TRC / ABS equivalent control means for commanding the output torque value to the motor of each motor and wheel system .