JPH09130921A - Speed controller for motor vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate changing of direction by reducing the reaction when an assistant tries to change the direction manually while allowing correct drive and reverse speed control. SOLUTION: The speed controller for a motor vehicle having left and right wheels being driven independently through individual motors 2A, 2B comprises encoders 6A, 6B for detecting the rotational speed, means for designating a reference rotational speed, and sections 15A, 15B for controlling the rotational speed of wheel by controlling power supply to the motors 2A, 2B based on the reference rotational speed and an actual rotational speed being fed back. Speed control sections 15A, 15B controls power supply based on the reference speed and the means speed of left and right wheels determined at a mean speed detecting section 17 and fed back.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control device for an electric vehicle in which left and right wheels are driven by separate motors.

[0002]

2. Description of the Related Art An electric vehicle in which one motor drives two or more wheels has a differential between the wheels, and the differential absorbs the rotational speed difference between the left and right wheels during turning. In this case, in order to control the speed of the vehicle, it is sufficient to control the output of one motor.

On the other hand, due to structural requirements of the vehicle and the like, there is a vehicle that does not have a differential and is equipped with a motor for each of the left and right wheels, and each motor drives the left and right wheels independently. In such a case, the output of each motor is controlled according to the operation for speed command or the like. For example, in an electric wheelchair, a joystick is provided in a self-propelled operation section operated by an occupant. The joystick is adjusted in accordance with the tilting operation of the joystick, and forward / backward and left / right turn are performed. The drive of the motor is controlled independently.

In the speed control of such an electric vehicle such as an electric wheelchair, the actual rotation speed of each wheel is detected so as to follow a driving command given by an occupant and not to become an excessive speed even when going downhill. This is fed back and the output of the motor is controlled based on the comparison between the feedback value and the command value.

That is, an example of a conventional speed control device of this type will be described with reference to FIG. 4. In this device, the left and right wheels are individually provided with motors 2A and 2B and a motor driver for supplying current to them. A drive system having 3A and 3B and pulse encoders 6A and 6B for detecting the motor rotation speed is provided, while an operation unit 107 having a joystick or the like is provided, and the operation unit 107 is also provided.
Between the drive system of each wheel and the command value processing unit 11
1, left and right wheel speed distribution unit 114, left and right speed control unit 115
A control system including A and 115B, left and right speed detection units 116A and 116B, and the like is provided.

Then, a forward / backward movement command, a left / right movement command, a main switch signal, a speed switch signal, etc. are output from the operation section 107, and the command value processing section 111 takes into account dead zones, maximum speeds, acceleration / deceleration, etc. The values are processed and sent to the left and right wheel speed distribution unit 114, and the left and right wheel speed distribution unit 114 gives the command speeds ω1 ₀ and ω2 ₀ to the left and right speed control units 115A and 115B, respectively, and the encoders 6A. , 6B are sent to the speed detectors 116A, 116B, and correction speeds obtained by multiplying the detected speeds ω1, ω2 by constant coefficients G1, G2 are given to the speed controllers 115A, 115B. . The speed control units 115A and 115B output voltage command values e1 ₀ and e2 ₀ corresponding to the difference between the command speed and the correction detection speed to the motor drivers 3A and 3B.

[0007]

By the way, for example, in the above-mentioned electric wheelchair, in addition to the self-propelled operation section, an assistance operation section operated by an assistant may be provided.
In this case, since the caregiver operates while standing behind the wheelchair while walking, it is difficult to operate accurately with an operation means such as a joystick for adjusting the traveling speed and direction. Also, a large amount of force is required to move the wheelchair forward and backward, but not so much if only changing the direction.

Therefore, the assisting operation section is provided with a simple switch for instructing forward / backward movement, the forward / backward movement is performed by driving a motor according to the switch operation, and the direction change is manually performed by an assistant. It is more convenient to do. In this case, to control the motors for the left and right wheels, a signal corresponding to the switch operation from the assistance operation unit is used to set the speed command when the joystick of the self-propelled operation unit is set to a specific operation position within the forward / backward operation range. By treating as equal to the signal, it is possible to control the motor based on the reference rotation speed and the actual rotation speed corresponding thereto.

However, according to such control, the switch operation gives the same instructed speed to the left and right wheels, and the control system for each wheel performs feedback control so as to maintain the instructed speed. Even if the caregiver tries to change the traveling direction of the wheelchair manually to change the direction, the speed difference does not easily occur between the left and right wheels.

Explaining it concretely by using mathematical expressions, the current i1 flowing in one motor 2A in FIG. 4 is the voltage e1 applied to the motor 2A and the induced voltage (Kv.ω1) of the motor.
And the resistance R of the entire closed circuit between the battery and the motor, the following equation is obtained. Note that Kv is a constant coefficient.

[0011]

[Expression 1] i1 = (e1−Kv · ω1) / R Further, the voltage applied to the motor 2A is the speed control unit 11
By the control at 5 A, the following equation is obtained. In addition, G1,
K1 is a constant coefficient.

[0012]

[Equation 2] e1 = e1 ₀ = (ω1 ₀ −G1 · ω1) · K1 Substituting this into the equation of Equation 1,

[0013]

## EQU3 ## i1 = {(ω1 ₀ −G1 · ω1) · K1−Kv · ω1} / R. The average speed of the left and right motors when the electric vehicle is turning is ωa, and the motor speeds ω1 and ω2 are
Where ω1 = ωa + Δω and ω2 = ωa−Δω, the arithmetic expression of the current command value is transformed as follows.

[0014]

[Equation 4] i1 = {ω1 ₀ · K1− (G1 · K1 + Kv) ωa− (G1
・ K1 + Kv) ・ Δω} / R As can be seen from this equation, the deviation Δω in the rotation speed of the motor
If, then (G1 · K1 + Kv) · Δ in this equation
The term ω works so as to change the current i1 in the direction of eliminating the deviation Δω of the rotation speed. That is, when ω1> ω2, it works to reduce the current i1, and when ω1 <ω2, it works to increase the current i1. Since the current i1 and the torque are in a proportional relationship, if the caregiver tries to change the traveling direction by human power while traveling straight ahead, the control is performed in a direction to eliminate the deviation Δω caused thereby and the motor sees from the caregiver. There is a problem that the reaction force of is increased and the direction change by human power becomes very heavy.

To solve this problem, the speed gain K1
It is conceivable that the output change is slowed down with respect to the speed fluctuation Δω. However, if this is done, the average speed ωa
The compensating effect of is decreased, that is, the responsiveness of the speed control is reduced when the load fluctuates, so there is the inconvenience that the speed drops sharply on the uphill and you can not climb up, or the speed increases on the downhill. Occurs.

In view of the above-mentioned circumstances, the present invention reduces the reaction force when an assistant or the like attempts to change the direction manually while enabling speed control appropriately for forward and reverse travel. The present invention provides a speed control device for an electric vehicle that can easily change the direction by a helper or the like.

[0017]

The invention according to claim 1 is
In an electric vehicle in which left and right wheels are independently driven by separate motors, speed detection means for detecting the actual rotation speed of each wheel, means for designating a reference rotation speed of the wheels, and this reference rotation A control means for controlling the rotation speed of the wheels by controlling the electric power supplied to the motor based on the value obtained by feeding back the speed and the actual rotation speed, and the control means controls the motor for one of the wheels. The left and right wheel-related control is performed by reflecting the rotation speed of the other wheel to feed back the value calculated to reduce the influence of the difference in the rotation speed of the left and right wheels on the control amount. It is a thing.

According to this device, even when a difference in rotational speed occurs between the left and right wheels, the electric power supplied to the motor is controlled based on the value calculated so as to reduce the influence of the difference in rotational speed on the control amount. Therefore, the speed control is performed while allowing the rotation speed difference. Therefore, when an assistant or the like tries to manually change the traveling direction from a straight traveling state, the difference in rotational speed between the left and right wheels due to the change in the traveling direction is allowed, and the reaction force from the motor is reduced.

According to a second aspect of the invention, in the device of the first aspect of the invention, the control means feeds back the average value of the actual rotational speeds of the left and right wheels as a reference for the left and right wheels and the reference rotational speed. The power supply to the motor is controlled based on the above.

According to this device, the average value of the left and right wheels is controlled so as to be the reference rotation speed, so that the traveling speed is appropriately controlled and the rotation speed difference between the left and right wheels is allowed. The reaction force from the motor when the vehicle tries to change the traveling direction is reduced.

According to a third aspect of the present invention, in the device of the first aspect of the invention, the control means controls left and right wheel control of electric power supplied to a motor for one wheel, and controls the other wheel. The rotation speed is fed back and is based on the reference rotation speed.

According to this apparatus, for example, the control for the right wheel is performed by using the value obtained by feeding back the actual rotation speed of the left wheel, whereby the deviation of the rotation speed of the left and right wheels affects the current supplied to the motor. The influence can be reduced as compared with the conventional device. Therefore, it becomes possible to reduce the reaction force from the motor when the caregiver or the like tries to change the traveling direction.

According to a fourth aspect of the present invention, in the device according to any one of the first to third aspects, the control means controls the left and right wheels, and the command rotation speed and the actual rotation speed for each wheel. It is possible to selectively execute left and right wheel independent control for independently controlling the power supply to the motor based on and, and for this control means, the left and right wheel related control and the left and right wheel independent control are performed. Is provided with switching means for switching the control system.

According to this device, when the joystick is operated, for example, the left and right wheels are independently controlled so that the forward and backward movements and the traveling direction can be changed by driving the motor. When traveling is performed by operating the switch of the operation unit, the left and right wheel-related control is performed to reduce the reaction force from the motor when the traveling direction is changed by an assistant or the like. Further, the left and right wheel-related control and the left and right wheel independent control are basically selected and changed only by changing the way of feeding back the actual rotation speed detected by the speed detection means while using a common control circuit. be able to.

[0025]

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

FIG. 1 shows a first embodiment of the device of the present invention applied to an electric wheelchair. In this figure, 1A
Is a drive system for the right wheel, 1B is a drive system for the left wheel, and the drive systems 1A and 1B are DC motors 2A and 2B, respectively.
To supply electric power to the motors 2A and 2B,
It is provided with motor drivers 3A and 3B for driving 2B, and each wheel is driven by separate motors 2A and 2B.

The circuits between the motor drivers 3A, 3B and the motors 2A, 2B are provided with current sensors 4A, 4B for detecting the current supplied to the motors. The current detection signals by the current sensors 4A, 4B are provided. Is fed back to the input units 5A and 5B for the motor drivers 3A and 3B, the deviation between the current command value and the current detection signal described later is obtained by the input units 5A and 5B, and the signal is given to the motor drivers 3A and 3B. Therefore, the motor 2A,
The current supplied to 2B is controlled so as to match the current command value. Further, pulse encoders 6A and 6B as speed detecting means for detecting the rotation speed are provided for the respective motors 2A and 2B.

On the other hand, as an operation unit for speed command,
A self-propelled operating unit 7 and an assisting operating unit 8 are provided.

The self-propelled operating section 7 is for an occupant of a wheelchair to operate, and includes a joystick 7a that can be tilted in various directions from the neutral position, a main switch, a speed switch, etc. (not shown). I have it. Self-propelled operating unit 7
Inside the, the first variable resistor whose resistance value changes according to the front-back direction component of the tilt when the joystick 7a is tilted and the second variable resistor whose resistance value changes according to the left-right direction component (Not shown) is provided, and the output parts of these variable resistors output signals of forward / backward movement commands and left / right movement commands which vary according to the manipulated variable. Further, a main switch signal, a speed switch signal and the like are also output from the operation section 7.

The assistance operation section 8 is for an assistant to perform an operation, and is a switch 8a for forward / backward command.
And a main switch, speed switch, etc., not shown. The forward / backward command switch 8a is a switch that only commands forward and backward movements, and a forward command of a constant speed or a backward command of a constant speed that is set in advance is output according to the switching operation of this switch. In this case, a fixed resistor that provides a constant resistance value for each of forward and backward movement is provided inside the assistance operation portion 8 so that the joystick 7a in the self-propelled operation portion is moved forward or backward by a predetermined amount. A signal equivalent to the forward / backward command signal when tilted may be output according to the operation of the switch 8a. Alternatively, the switch 8a may be a simple changeover switch, and a constant command speed may be stored in the main controller 10 described later. In addition to the signals for the forward command and the reverse command, a main switch signal, a speed switch signal, etc. are also output from the assistance operation section.

The operation sections 7 and 8 are connected to the input side of a main controller 10 as control means, and the output side of the main controller 10 is connected to the input section 5A of the motor drivers 3A and 3B of the drive systems. , 5B are connected, and the encoders 6A, 6B are also connected to the main controller 10.

The main controller 10 controls the rotational speed of the wheels by controlling the electric power supplied to the motors 2A and 2B based on the rotational speed designated by the operating section and the value obtained by feeding back the actual rotational speed. To do.
Particularly, when a constant reference rotation speed is designated by a forward movement command or a backward movement command from the assistance operation unit 8 and the electric power supplied to the motors 2A and 2B is controlled based on this and the actual rotation speed, Left and right wheel related control is performed. This left and right wheel related control reflects the rotation speed of the other wheel in the control of the motor for one wheel,
The value that is calculated so as to absorb the rotation speed difference between the left and right wheels is fed back for control, and in the present embodiment, the average value of the actual rotation speeds of the left and right wheels is fed back to the reference rotation speed. Based on the motor 2A, 2B
It is designed to control the power supplied to the device.

Further, the controller 10 can selectively execute the left and right wheel-related control and the left and right wheel independent control, and when the command from the self-propelled operating section 7 is issued, the left and right wheel independent control is performed. Has become. This left and right wheel independent control independently controls the power supplied to the motors 2A and 2B based on the command rotation speed and the actual rotation speed for each wheel.

The internal structure of the main controller 10 will be described in detail.
Command value processing units 11 and 12 respectively corresponding to the self-propelled operation unit 7 and the assistance operation unit 8, a control switching flag 13,
The left and right wheel speed distribution unit 14, the speed control units 15A and 15B for the left and right wheels, and the speed detection units 16A and 16B for the left and right wheels.
It has 16B and the average speed detection part 17.

The command value processing unit 11 is a self-propelled operating unit 7
The command value is processed in response to a signal from the controller to set the dead zone, maximum speed, acceleration / deceleration, etc. in the speed operation range, and the command value is corrected based on these. Further, the command value processing unit 12 receives a signal from the assistance operation unit 8 and processes the command value, for example, the maximum speed,
Acceleration / deceleration etc. are set.

The signals passed through the command value processing units 11 and 12 are input to the left and right wheel speed distribution unit 14 via a control switching flag 13 as a switching unit between the left and right wheel independent control and the left and right wheel related control. When the control switching flag 13 is on the self-propelled side (“1” side) as indicated by the broken line, the signal output from the self-propelled operation unit 7 and passed through the command value processing unit 11 is sent to the left and right wheel speed distribution unit 14. In addition, as shown by the solid line, when switching to the assistance side (“0” side), a signal output from the assistance operation unit 8 and passed through the command value processing unit 12 is given to the left and right wheel speed distribution unit 14. Is.

[0037] The left and right wheel speed distribution unit 14, if the signal from the free-running operation section 7 is given on the basis of the forward-reverse command and lateral advance command, the command speed .omega.1 ₀ and the left wheel side of the right wheel side And the command speeds ω2 ₀ of the left and right speed control units 15A and 15B.
Give to B. Further, when a signal is given from the assistance operation section 7, the left and right constant reference rotational speeds ω1 ₀ (= ω
2 ₀₎ left and right speed control unit 15A, 15B of the input unit 18
It is designed to be given to A and 18B.

The speed control units 15A and 15B, the speed detection units 16A and 16B, and the average speed detection unit 17 are operated depending on whether the self-propelled operation unit 7 is operated or the assistance operation unit 8 is operated. Then, the following processing is performed.

That is, as the left and right wheel independent control performed when the self-propelled operating unit 7 is operated, the detected speeds from the left and right pulse encoders 6A and 6B are input to the speed detecting units 16A and 16B, respectively. Each of these speed detectors 1
From 6A and 16B, the correction detection speed obtained by multiplying the detection speeds ω1 and ω2 by constant coefficients G1 and G2 is the speed control unit 15A,
It is given to the input parts 18A and 18B of 15B. And
According to the difference between the commanded speed and the correction detection speed, the speed control units 15A and 15B make this difference and a constant coefficient K1,
The command value of the current supplied to the motors 2A, 2B is obtained from K2, and this current command value is used for the motor driver 3A,
It is given to the input sections 5A and 5B of 3B.

As the left and right wheel-related control performed when the assistance operation section 8 is operated, the detection speeds ω1 and ω2 of the left and right wheels from the pulse encoders 6A and 6B are added by the addition section 19 and averaged. It is input to the speed detection unit 17,
From the average speed detection unit 17, the detected speed ω1
, Ω2 multiplied by a constant coefficient Gm, the corrected average speed is input to the speed control units 15A and 15B.
Given to. Then, the speed control units 15A and 15B
Thus, according to the difference between the command speed and the calibrated average speed, command values i1 ₀ and i2 _{0 of the} current supplied to the motors 2A and 2B are obtained from this difference and constant coefficients K1 and K2, and the current command value i1 ₀ and i2 ₀ are given to the input sections 5A and 5B of the motor drivers 3A and 3B.

Table 1 shows the settings of various parameters used for the above control during self-propelled operation and during assisted operation.

[0042]

[Table 1]

As shown in this table, either the main switch for self-propelling or assisting is turned on, the switching flag is switched between self-propelling and assisting, and the coefficients K1 and K2 are
It is set to a constant value a even when assisting. Further, as the coefficients G1 and G2, a constant conversion value c is set for uniting the detection value by the pulse encoder and the command speed, and the coefficient G
As m, c / 2 is set so that the average value of the speed can be obtained together with the conversion for unit adjustment. The commanded speed is arbitrary when self-propelled and the same constant value on the left and right when assisting (ω1 ₀ =
ω2 ₀ ). If both the main switch for self-propelled and the main switch for assistance are ON, it will be turned ON later, for example.
Only the side said to be valid.

The operation of the apparatus of this embodiment (mainly the operation at the time of assistance) will be described below.

When the switch 8a of the assistance operation section 8 is operated to give a forward or backward command at a constant speed,
Based on the constant reference speed ω1 ₀ and the detected speed, the current command value i1 ₀ is calculated by the speed control unit as in the following equation.

[0046]

[Expression 5] i1 ₀ = {ω1 ₀ − (ω1 + ω2) · Gm} · K1 Let the average speed of the left and right motors be ωa when the electric vehicle is traveling (including turning), and ω1 = ωa + Δω, ω2 =
When ωa−Δω, the arithmetic expression of the current command value i1 ₀ is modified as follows.

[0047]

[Equation 6] i1 ₀ = (ω1 ₀ -2 · ωa · Gm) · K1 = (ω1 ₀ −c · ωa) · K1 This expression includes the term of the deviation Δω between the left and right rotational speeds with respect to the average speed ωa. I can't. Therefore, as long as the average speed ωa is kept constant, the current command value i1 ₀ does not change even if the left and right rotational speeds differ and the deviation Δω occurs.

Therefore, even if the assistant changes the traveling direction manually from the straight traveling state of the electric wheelchair by the operation of the assistance operation unit 8, even if the rotation speeds of the left and right wheels become different, the motor current command value i1 ₀ related to the torque does not change, the reaction force from the motor is not increased.

That is, when the left and right wheels are assisted with the same reference rotation speed, the left and right motors are controlled independently of each other as in the conventional case. When the rotation speed of each wheel deviates from the reference rotation speed by the control, the control for individually returning to the reference rotation speed is performed on the left and right sides, so that the reaction force with respect to the change in the traveling direction becomes large, but according to the present embodiment, As long as the average speed is maintained, the difference between the rotational speeds of the left and right wheels is allowed to occur, so that the reaction force when the traveling direction is changed is reduced. Further, since the coefficient K1, which is a speed gain, effectively acts on the fluctuation of the average speed ωa, it is possible to maintain a stable average speed during climbing and descending slopes.

In the above description of the operation of the apparatus of this embodiment, the control of the motor 2A for the right wheel has been described, but the calculation of the current command value for the motor 2B for the left wheel may be performed in the same manner.

When the joystick 7a of the self-propelled operating portion 7 is operated, the command speeds of the left and right wheels are individually given in response to the operation, and based on this, the left and right motors 2 are driven.
By independently controlling A and 2B, the change of the traveling direction and the like are also performed by driving the motors 2A and 2B. In this case, when a disturbance is applied to the left and right wheels, the motors 2A and 2B generate a reaction force against the disturbance, and stable traveling can be maintained so as to match the command speed.

FIG. 2 shows a second embodiment of the speed control device of the invention, and this second embodiment will be described. The same parts as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the left and right speed control units 15A and 15B in the main controller 10 command voltage values e1 ₀ and e2 ₀ to the motor drivers 3A and 3B.
Is output. When such a voltage control is performed, the induced voltage generated with the rotation of the motor affects the reaction force when the traveling direction is changed, and therefore the induced voltage compensator 20A is provided on each of the left and right voltage command value output sides. , 20
B is provided, and the induced voltage compensation values obtained by multiplying the motor rotation speeds ω1 and ω2 by constant coefficients H1 and H2 by the induced voltage compensation units 20A and 20B are added to the voltage command values e1 ₀ and e2 ₀ and the addition unit 21A, Motor driver 3 after adding in 21B
It is given to A and 3B.

Also in this embodiment, the speed controller 15
A and 15B are command speeds that are individually given to the left and right and encoders 6A and
Depending on the difference from the correction detection speed given from 6B through the speed detection units 16A, 16B, constant coefficients K1, K2
The voltage command values e1 ₀ and e2 ₀ are obtained by multiplying by and output. On the other hand, at the time of assistance in operating the assistance operation unit 8,
Depending on the difference between the same reference rotational speed ω1 ₀ (= ω2 ₀ ) on the left and right and the average speed given from the left and right encoders 6A and 6B via the average speed detection unit 17, constant coefficients K1 and K
The voltage command values e1 ₀ and e2 ₀ are obtained by multiplying by 2 and output.

Table 2 shows the settings of various parameters used for control by the apparatus of the second embodiment during self-propelling and during assistance.

[0056]

[Table 2]

That is, the coefficients H1 and H2 for obtaining the induced voltage compensation value are set to the predetermined value d when assisting. The other parameter settings are the same as in Table 1.

The operation of the apparatus of the second embodiment (mainly when assisting) will be described below.

[0059] when assistance switch 8a of the assistant operation unit 8 is operated, a current i1 flowing through the motor 2A is provided with a voltage command value e1 _0, the induced voltage compensation value (ω1 · H1), the induced voltage (K
From v · ω1) and the resistance R, the following equation is obtained. In addition,
Kv is a constant coefficient.

[0060]

## EQU7 ## i1 = (e1 ₀ + ω1H1−Kvω1) / R Further, the voltage command value e1 ₀ output from the speed controller 15A based on the constant reference speed ω1 ₀ and the detected speeds ω1 and ω2.
Is as follows:

[0061]

[Equation 8] e1 ₀ = {ω1 ₀ − (ω1 + ω2) · c / 2} · K1 Substituting this into the equation of Equation 7,

[0062]

[Equation 9] i1 = [{ω1 ₀ − (ω1 + ω2) · c / 2} · K1 +
ω1 · H1−Kv · ω1] / R, and ω1 = ωa + Δω and ω2 = ωa−Δω, the current value i1 is

[0063]

[Equation 10] i1 = {ω1 ₀ · K1− (c · K1−H1 + Kv)
ωa + (H1−Kv) · Δω} / R.

As can be seen from this equation, if the coefficient H1 is set so that H1 = Kv or H1≈Kv, in this equation, the influence of the deviation Δω between the left and right rotational speeds on the current i1 disappears, or It can be made small enough.

Therefore, also in this embodiment, when the assisting person manually changes the traveling direction from the straight traveling state of the electric wheelchair by the operation of the assisting operation section 8, the rotation speeds of the left and right wheels are different due to the change. However, the motor current i1 related to the motor torque hardly changes, and the reaction force from the motor 2A does not increase.

The calculation of the voltage command value, motor current, etc. for the motor 2B for the left wheel may be performed in the same manner.

The coefficient H1 is preferably the same as or close to Kv, but H1 = 0 may be set. In this way, -Kv
-Although the term of Δω remains, it is -G1 · K1 · Δ compared to-(G1 · K1 + Kv) Δω in the formula of Equation 4 in the case of the conventional device.
Since the influence of the rotation speed deviation Δω on the current is reduced by the amount of ω, the reaction force from the motor when the traveling direction is changed is reduced as compared with the conventional case. Further, since the coefficient K1 effectively acts on the fluctuation of the average speed ωa,
A stable average speed can be maintained when descending a slope.

FIG. 3 shows a third embodiment of the speed control device of the invention, and this third embodiment will be described. The same parts as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the apparatus of this embodiment, as the left and right wheel-related control performed at the time of assistance, the control of the electric power supplied to the motor for one wheel is based on the value obtained by feeding back the actual rotation speed of the other wheel and the reference rotation speed. It is supposed to be done.

More specifically, the left and right speed control units in the main controller 10 are the motor drivers 3
The voltage command values e1 ₀ and e2 ₀ are output to A and 3B, and the average speed detecting unit 17 provided in the first and second embodiments is not provided. To 2
The two speed detection units 16A and 16B are connected to the control switching flag 22.
It is adapted to be selectively connected to the left and right encoders 6A and 6B via A and 22B. That is, when the control switching flags 16A and 16B are on the self-propelled side ("1" side) as indicated by the broken line, the signal of the right encoder 6A is sent to the speed control unit 16A for right control, and the signal of the left encoder 6B is sent. The signals are sent to the speed control unit 16B for the left side control, but when the control switching flags 16A and 16B are switched to the assistance side (“0” side) as indicated by the solid line, the signal from the right side encoder 6A is controlled by the left side control. Speed detector 16
B, and the signal from the left encoder 6B is sent to the speed detecting section 16A for controlling the right side.

Table 3 shows the settings of various parameters used for control by the apparatus of the third embodiment during self-running and during assistance.

[0072]

[Table 3]

The operation of the apparatus of the third embodiment (mainly the operation at the time of assistance) will be described below. When assisting the operation of the switch 8a of the assistance operation unit 8, the control switching flags 13, 22A, 22B are on the assistance side indicated by solid lines. In this state, each speed control unit 15A, 15B
With standard rotational speed .omega.1 _0, is .omega.2 ₀ given to, the speed control unit 15A which controls the right motor 2A, by the detection value from the left encoder 6B is given through the speed detection section 16A, the speed control unit At 15A, the voltage command value e1 ₀ is obtained according to the difference between the reference rotation speed ω1 ₀ and the left speed detection value ω2, and this is output to the motor driver 3A of the right motor 2A. On the other hand, the speed control unit 15B for controlling the left motor 2B, the detection value from the right encoder 6A is by given via the speed detector 16B, in the speed control unit 15B, the reference rotational speed .omega.2 ₀ and right The voltage command value e2 ₀ is obtained according to the difference from the speed detection value ω1 and is output to the motor driver 3B of the left motor 2B.

The current i1 flowing in the right motor 2A is given by the following equation from the motor voltage e1, the induced voltage (Kvω1) and the resistance R.

[0075]

[Expression 11] i1 = (e1−Kv · ω1) / R The voltage of the right motor is given by the following equation.

[0076]

[Equation 12] e1 = e1 ₀ = (ω1 ₀ −G1 · ω2) · K1 Substituting this into the equation of Equation 11,

[0077]

[Equation 13] i1 = {(ω1 ₀ −G1 · ω2) · K1−Kv · ω1} / R, and if ω1 = ωa + Δω and ω2 = ωa−Δω, the current value i1 is

[0078]

[Expression 14] i1 = {ω1 ₀ · K1− (G1 · K1 + Kv) ωa +
(G1 · K1−Kv) · Δω} / R In this equation, as a term including the rotational speed deviation Δω, (G1 · K1
-Kv) · Δω remains, but G1> 0, K1> 0, Kv> 0
Then, if the conventional device is used,-(G1
・ K1 + Kv) ・ When comparing with Δω

[0079]

[Equation 15] | G1 · K1−Kv | <| G1 · K1 + Kv | Therefore, according to the present embodiment (G1 · K1−Kv)
.DELTA..omega. Has a smaller effect on the current i1. Therefore, the reaction force from the motor when the traveling direction is changed is reduced as compared with the conventional case.

Furthermore, G1 · K1 = Kv or G1 · K1
When the coefficients G1 and K1 are set so that ≈Kv, the Δω term disappears or is further reduced in the equation (14). Therefore, even if the above-mentioned deviation Δω occurs due to the assisting person manually changing the traveling direction from the straight traveling state of the electric wheelchair by operating the assistance operation section 8, the current i1 does not change and the reaction force from the motor increases. There is nothing to do. Further, since the coefficient K1 etc. effectively acts on the fluctuation of the average speed ωa, it is possible to maintain a stable average speed during climbing and descending slopes.

The voltage command value for the motor 2B for the left wheel, the motor current, etc. may be calculated in the same manner.

In each of the above embodiments, the case where the device of the present invention is applied to an electric wheelchair has been shown. However, if the left and right wheels are driven by separate motors without using a differential, an electric vehicle, an electric vehicle It can also be applied to golf carts, electric carts, and the like.

[0083]

The speed control device for an electric vehicle of the present invention controls the rotation speed of the vehicle by controlling the electric power supplied to the motor based on the reference rotation speed and a value obtained by feeding back the actual rotation speed. A value that is calculated so that the control means reflects the rotation speed of the other wheel on the control of the motor for one wheel and reduces the influence of the difference in the rotation speed of the left and right wheels on the control amount. Since the left and right wheel-related control is performed with feedback, it is possible for the helper etc. to travel while traveling at a stable speed that is not easily affected by load fluctuations when moving forward or backward. The reaction force of the motor when the direction is changed manually is reduced, and the direction can be easily changed with a small force.

Specifically, for example, the control means is configured to control the electric power supplied to the motor based on a value obtained by feeding back the average value of the actual rotation speeds of the left and right wheels and the reference rotation speed. As a result, the rotational speed difference between the left and right wheels can be allowed while controlling the average speed of the left and right wheels to the reference rotational speed, and the reaction force of the motor when the caretaker or the like changes the direction can be reduced.

Alternatively, the control means controls the electric power supplied to the motor for one of the wheels based on the value obtained by feeding back the actual rotation speed of the other wheel and the reference rotation speed as the control relating to the left and right wheels. Even if configured, it is possible to reduce the resistance of the motor when the caretaker or the like changes the direction.

Further, the left / right wheel-related control and the left / right wheel independent control for independently controlling the electric power supplied to the motor based on the command rotational speed and the actual rotational speed can be selectively executed. By doing so, it is possible to selectively use these controls depending on whether the vehicle is traveling by operating the joystick or traveling by operating the switch of the assistant operation unit, and the functionality of the electric vehicle can be enhanced. Moreover, these controls can be selected and changed only by changing the way of feeding back the actual rotation speed detected by the speed detection means, and the contents of the traveling control can be changed with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a structure of a speed control device for an electric vehicle according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a structure of a speed control device for an electric vehicle according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a structure of a speed control device for an electric vehicle according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing the structure of a conventional device.

[Explanation of symbols]

 2A, 2B motor 3A, 3B motor driver 6A, 6B pulse encoder 7 self-propelled operating unit 8 assisting operating unit 10 main controller 15A, 15B speed control unit 16A, 16B speed detection unit 17 average speed detection unit

Claims (4)

[Claims] 1. An electric vehicle in which left and right wheels are independently driven by separate motors, and speed detection means for detecting an actual rotation speed of each wheel and means for designating a reference rotation speed of each wheel. And a control means for controlling the rotation speed of the wheels by controlling the electric power supplied to the motor based on the value obtained by feeding back the reference rotation speed and the actual rotation speed, wherein the control means is one of The left and right wheel-related control is performed by reflecting the rotational speed of the other wheel in the control of the motor for the wheel and feeding back the value that has been arithmetically processed to reduce the influence of the rotational speed difference between the left and right wheels on the control amount. What is claimed is: 1. A speed control device for an electric vehicle. 2. The control means is configured to control the electric power supplied to the motor based on a value obtained by feeding back the average value of the actual rotation speeds of the left and right wheels and the reference rotation speed as the left and right wheel related control. The speed control device for an electric vehicle according to claim 1, wherein: 3. The control means controls the electric power supplied to the motor to one of the wheels as left and right wheel related control.
The speed control device for an electric vehicle according to claim 1, wherein the speed control device is configured to perform the operation based on a value obtained by feeding back the actual rotation speed of the other wheel and a reference rotation speed. 4. The left and right wheel independent control, wherein the control means independently controls the left and right wheel related control and the electric power supplied to the motor based on the command rotation speed and the actual rotation speed for each wheel. And a switching means for switching the control system between the left and right wheel-related control and the left and right wheel independent control is provided for the control means. 4. A speed control device for an electric vehicle according to any one of 3 above.