JP3320961B2 - Vehicle speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed control device for driving left and right driving wheels individually.

[0002]

2. Description of the Related Art Conventionally, a joystick is often used as a traveling instruction device for an electric wheelchair. This travel instructing device can tilt the joystick forward, backward, left and right, and causes the wheelchair to travel in the tilting direction, and controls the traveling speed according to the tilt angle. That is, when the joystick is tilted shallowly, the vehicle runs at a moderate speed, and when the joystick is tilted deeply, the vehicle runs at a high speed. Further, by operating the joystick, it is possible to move forward, backward, turn around, or rotate on the spot.

[0003] Since an electric wheelchair is used by a physically handicapped person, the maximum speed of the wheelchair is suppressed at most to such an extent that a healthy person can walk. Therefore, when the user becomes accustomed to driving an electric wheelchair, the joystick is often tilted to its limit and run at the maximum speed.

[0004]

However, if the joystick is suddenly operated to make a turn while traveling at the maximum speed, the turning radius can be increased even if the maximum speed is about the walking speed of a healthy person. Is small, a large centrifugal force is generated, and there is a possibility that the riding comfort may deteriorate.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a vehicle speed control device that prevents a deterioration in ride quality even when the vehicle suddenly turns while traveling at high speed.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a vehicle having left driving means for rotating a left driving wheel and right driving means for rotating a right driving wheel. A first operation of rotating and driving the left and right driving wheels in a direction opposite to each other at a predetermined wheel speed can be performed independently or simultaneously, and Operating means for instructing the command wheel speed of each drive wheel in accordance with the operation amount of each operation; and each of the command wheel speeds in accordance with the magnitude of the absolute value of the difference between the command wheel speeds of the designated drive wheels of a correction means for correcting to reduce the absolute value, and a drive control means for controlling the left drive unit and right drive unit to drive the rotation of each driving wheel in the corrected respective commanded wheel speed was above Correction means
The larger the absolute value of the difference between the command wheel speeds of each drive wheel,
Increase the degree to which the absolute value of each command wheel speed is reduced
It is obtained by way (claim 1).

[0007] According to this configuration, the command wheel speeds of the left and right drive wheels are instructed by the operation means in accordance with the operation amount of the first operation and the operation amount of the second operation, and the instructed drive wheels are used. According to the magnitude of the absolute value of the difference between the command wheel speeds of
Correction for reducing the absolute value of each command wheel speed is performed by the correction means. Then, the left driving unit and the right driving unit are controlled to rotationally drive the left and right driving wheels at the corrected command wheel speeds. Thereby, when the absolute value of the difference between the command wheel speeds of the respective drive wheels is large due to the operation performed by the operating means, that is, when the traveling turning radius of the vehicle is small, the command wheel speeds are corrected to be small, and the centrifugal force generated in the vehicle is reduced. Power drops.

In a vehicle provided with left driving means for rotating the left driving wheel and right driving means for rotating the right driving wheel, the left and right driving wheels are rotated in the same direction at the same wheel speed. The first operation to be performed and the second operation to rotate the left and right drive wheels at predetermined wheel speeds in opposite directions to each other can be performed either alone or simultaneously, and according to the operation amount of each of the above operations. Operating means for instructing the command wheel speeds of the respective drive wheels; acceleration calculating means for calculating the centrifugal acceleration of the vehicle using the designated command wheel speeds of the respective drive wheels; and Comparing means for comparing the set value with the set value, and when the centrifugal acceleration is larger than the set value, a correcting means for correcting the command wheel speed of each drive wheel so that the centrifugal acceleration matches the set value. This corrected the commanded wheel speed is obtained by a drive control means for controlling the left drive unit and right drive unit to drive the rotation of each drive wheel (claim 2).

According to this configuration, the command wheel speeds of the left and right driving wheels are instructed by the operating means in accordance with the operation amount of the first operation and the operation amount of the second operation. Is used to calculate the centrifugal acceleration of the vehicle. When the calculated centrifugal acceleration is larger than a preset value, the command wheel speed of each drive wheel is corrected so that the centrifugal acceleration matches the set value. And
The left driving unit and the right driving unit are controlled to rotate the left and right driving wheels at the corrected command wheel speeds. As a result, even when the traveling turning radius of the vehicle is small due to the operation performed by the operation means, the centrifugal acceleration generated in the vehicle is maintained at or below the set value, so that the reduction in the riding comfort of the vehicle is reliably prevented.

[0010] The operating means may instruct each of the command wheel speeds by reducing the weight of the operation amount of the second operation as compared with the operation amount of the first operation. ).

According to this configuration, the command wheel speed of each drive wheel is instructed by reducing the weight of the operation amount of the second operation as compared with the operation amount of the first operation, so that the operation is performed by the operation means. The absolute value of the difference between the command wheel speeds of the respective drive wheels is reduced as compared with the operation amount. Therefore, since the traveling turning radius of the vehicle does not become small, a large centrifugal force is not generated in the vehicle, and the decrease in the riding comfort of the vehicle is more reliably prevented.

In the vehicle speed control device according to any one of claims 1 to 3, a radius calculation for calculating a traveling turning radius of the vehicle using a command wheel speed of each of the drive wheels instructed by the operation means. Means, wherein the correcting means corrects the command wheel speed of each of the driving wheels so that the traveling turning radius does not change (claim 4).

According to this structure, the command wheel speed of each drive wheel is corrected so that the traveling turning radius of the vehicle does not change due to the operation performed by the operation means, so that the operability of the vehicle is not reduced. The ride comfort does not decrease.

[0014]

[0015]

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of the present invention will be described with reference to FIG. FIG. 12 is a schematic diagram illustrating the speeds and turning radii of the drive wheels when the vehicle turns.

[0017] In the figure, V _L is the wheel speed of the left driving wheel (hereinafter, referred to as the left wheel speed), V _R is the right wheel speeds of the drive wheels (hereinafter, referred to as the right wheel speed), the speed of V _C is the vehicle , _RL is the turning radius of the left driving wheel, _RR is the turning radius of the right driving wheel, _RC
Is the turning radius of the vehicle, and TREAD is the tread of the vehicle. Since the vehicle in FIG. 12 shows a state in which turning to the right, V _L> V _R, an _{R L>} R R.

Generally, the centrifugal force generated in a vehicle is:

[0019]

## EQU1 ## Centrifugal force = weight × (traveling speed) ² / traveling radius. Therefore, even if the vehicle travels at the same speed, a smaller centrifugal force is generated as the traveling turning radius is smaller.

Also, from FIG.

[0021]

[Equation 2] TREAD = R _L -R _R

[0022]

## EQU3 ## V _L / V _R = R _L / R _R

[0023]

## EQU4 ## R _C = R _R + TREAD / 2

[0024]

## EQU5 ## Each equation of V _C = (V _L + V _R ) / 2 is obtained.

From the above equations (2) and (3),

[0026]

[6] _{TREAD = R R × V L /} V R -R R = R R × (V L -V R) / V R is obtained by modifying this equation,

[0027]

Equation 7] _{R R = V R × TREAD /} (V L -V R) is obtained. Substituting this equation 7 into the above equation 4 gives

[0028]

Equation 8] _{R C = R R + TREAD /} 2 = V R × TREAD / (V L -V R) + TREAD / 2 = TREAD × {1/2 + V R / (V L -V R)} is obtained.

Here, consider the case where the vehicle travels forward at a constant speed, that is, the case where V _C is constant and V _L , V _R ≧ 0.

According to the above equation (8), the traveling turning radius R _C is
Determined by the _{V R / (V L -V R} ). On the other hand, since the speed V _{C of} the vehicle is constant, (V _L + V _R ) is constant from the above equation (5). Therefore, an increase in the vehicle speed difference (V _L -V _R ) between the left and right drive wheels (hereinafter, referred to as left and right wheels) means that the right wheel vehicle speed V
_R means that V _R / (V _L −
V _R ) is reduced.

Accordingly, as the vehicle speed difference (V _L -V _R ) between the left and right wheels increases, the running turning radius _RC decreases, so that the centrifugal force generated in the vehicle increases from the above equation ( ₁ ). Note that, contrary to the case of FIG. 12, the same applies to the case where V _R > V _L turning to the left.

Therefore, according to the present invention, even if a command for increasing the absolute value of the vehicle speed difference between the left and right wheels is given by the operating means using the above characteristics of the vehicle, each drive wheel is driven in accordance with the command. Instead, the speed of each drive wheel is automatically reduced, so that even if the vehicle is turned while the command from the operating means remains at the maximum speed, deterioration of the riding comfort is prevented.

An embodiment of an electric wheelchair to which the present invention is applied will be described below. FIG. 1 is a block diagram showing a control configuration of the first embodiment.

This electric wheelchair includes an operation panel 1, a power supply unit 2, motors 3L and 3R, relays 4L and 4R, motor control units 5L and 5R, a control board 6,
PU7.

The operation panel 1 has a joystick 11 and a main switch 12 for the occupant to operate. The joystick 11 constitutes operating means for operating the traveling of the electric wheelchair, and can be tilted in a 360 ° direction around its base as a fulcrum. The vehicle speed is instructed according to the tilt angle, which is the tilt depth, and an operation signal corresponding to the operation amount, that is, an operation signal corresponding to the front-rear direction component and a left-right component of the tilt angle is output. Is configured.

The main switch 12 is interposed between the power supply unit 2 and the control board 6, and operates to turn on / off the power supply to the control board 6. The power supply unit 2 includes a storage battery or the like, and supplies power to each unit.

The motor 3L, the relay 4L, and the motor control unit 5L constitute left driving means for driving the left driving wheel of the electric wheelchair. The motor 3R, the relay 4R, and the motor control unit 5R perform right driving. The right driving means for driving the wheels is configured.

The motors 3L and 3R rotate left and right wheels of the electric wheelchair, respectively, and are connected to motor controllers 5L and 5R via relays 4L and 4R, respectively. Vehicle speed sensors 31L, 31R are provided on the motors 3L, 3R, respectively. Vehicle speed sensor 31L,
31R is composed of a pulse encoder, an optical sensor, and the like, detects the rotational speed of the motor, and outputs a pulse signal corresponding to the detected speed.

The relays 4L and 4R have common contacts 41L and 41R, ON contacts 42L and 42R, and OFF contacts 43L and 43R, respectively.
Is controlled by the In FIG. 1, each of the relays 4L and 4R shows an ON state.

The motor control units 5L and 5R supply drive currents to the motors 3L and 3R, respectively, and the supply current level is controlled by the CPU 7.

The control board 6 includes input / output interfaces (hereinafter, referred to as IFs) 61 to 64, a CPU,
The CPU 7 includes a joystick input unit 71, a command vehicle speed calculation unit 72, and a vehicle speed calculation unit 7.
3. A command vehicle speed correction calculator 74 and a PWM wave calculator 75 are provided. The memory 8 stores various data such as a control program and a maximum speed Vmax and a set value Gmax, which will be described later.

The IF 61 is interposed between the joystick 11 and the joystick input unit 71, and
Are the motor control units 5L and 5R and the PWM wave calculation unit 75
The IF 63 is provided between the relays 4L and 4R and the command vehicle speed correction calculator 74, and the IF 64 is provided between the vehicle speed sensors 31L and 31R and the vehicle speed calculator 73. It performs input / output processing of various signals.

The joystick input section 71 has an IF6
Signals relating to the tilt direction and the tilt angle of the joystick 11 are A / D-converted and input via 1. The joystick input unit 71 calculates the forward and backward components and the left and right components of the tilt angle from this input signal,
2 is output. These values are positive when the joystick 11 is tilted forward (to the right),
It is negative when tilted backward (to the left).

[0044] The command speed calculator 72, the front-rear direction component and the left-right direction component of the tilt angle of the joystick 11, tentatively calculates a command vehicle speed V _R of the command vehicle speed V _L and a right wheel of the left wheel, the command vehicle speed correction calculation unit 74.

Here, referring to FIG.
Calculation of the left wheel speed V _L and a right wheel speed V _R in 2 will be described. FIG. 2 is an explanatory diagram showing the tilt direction and the tilt angle of the joystick 11, and Rmax indicates a stroke when the tilt angle is the maximum.

[0046]

Equation 9] V _L = F ₁ (front-rear direction component of the inclination angle, the horizontal direction component of the tilt angle) V _R = F ₂ (front-rear direction component of the inclination angle, the horizontal direction component of the tilt angle) command vehicle speed calculating unit 72 , Left wheel speed V _L and right wheel speed V
_R is calculated by the functions F ₁ and F ₂ using the forward and backward components and the left and right components of the tilt angle of the joystick 11 as parameters as shown in Expression 9 above.

In the case where the joystick 11 is tilted in the + direction in the front-rear direction and the left-right component = 0, that is, in the case of FIG. 2, the functions F ₁ and F ₂ are set so that V _L = V _R. As a result, the electric wheelchair travels forward.

When the joystick 11 is tilted in the + direction including the front-rear direction component and the left-right direction component, that is, in the case of FIG. 2, the functions F ₁ and F ₂ satisfy V _L >
Is set so that V _R, whereby electric wheelchair is turning to the right.

In the case where the joystick 11 is tilted in the + direction in the left-right direction and the front-rear component = 0, that is, in the case of FIG. 2, the functions F ₁ and F ₂ indicate that the rotation directions of the left and right wheels are reversed. The absolute value of the speed is set to be equal, that is, V _L = −V _R > 0, whereby the electric wheelchair rotates in place.

FIG. 3 shows that when the joystick 11 is rotated from the front (+) of the front-rear direction component to the right (+) of the left-right direction component at the maximum tilt angle as shown in FIG. component values X left wheel speed V _L for (maximum 100), the right wheel speed V _R, the vehicle speed difference between the left and right wheels (V _L -V _R)
FIG. 4 is a diagram showing a vehicle speed V _C = (V _L + V _R ) / 2.

In FIG. 3, the functions F ₁ and F ₂ of the above equation (9) are

[0052]

V _L = F ₁ (Y, X) = Y + pX V _R = F ₂ (Y, X) = Y−pX, and the maximum speed of V _L and V _R is 100. In addition,
p is a coefficient representing the weighting of the left-right component with respect to the front-rear component. Assuming that p = １ ／ in the above equation 10, X ² + Y ² = Rmax ²

[0053]

V _L = Y + ／ X = √ (Rmax ² −X ² ) + ／ X V _R = Y− ／ X = √ (Rmax ² −X ² ) − ／ X The V _L, of the representation of the V _R is FIG.

In FIG. 3, the point A is V _R = 0 and the right 90
° indicates the turning point B is V _L = -V _R = 50, shows the spot turn. In the range of X = 0 to X _1, left wheel speed V _L is the maximum speed 10 the calculated value shown by a broken line shown by a solid line
Limited to zero.

[0055] As shown in FIG. 3, with the calculated result of the command vehicle speed calculating unit 72, a vehicle speed difference between the left-right direction component X increases right and left wheels (V _L -V _R) is monotonically increasing.

Returning to FIG. 1, the vehicle speed calculation unit 73 outputs
4, the actual speeds of the left and right driving wheels, that is, the actual vehicle speeds v _L and v _R are calculated using the pulse signals input from the vehicle speed sensors 31L and 31R, and these are calculated by the command vehicle speed correction calculation unit 74 and the PWM. The signal is output to the wave calculator 75.

[0057] command vehicle speed correction calculation unit 74 according to the procedure described below, correction command vehicle speed V _L of the left wheel to correct the left wheel speed V _L and a right wheel speed V _R, which is calculated by the command vehicle speed calculating unit 72 ' And the correction command vehicle speed V _R ′ for the right and left wheels, and outputs the calculated correction command vehicle speeds V _L ′, V _R ′ for the left and right wheels to the PWM wave calculation unit 75.

[0058] First, a left wheel speed V _L and a right wheel speed V _R, which is calculated by the command vehicle speed calculation unit 72, the absolute value of the vehicle speed difference |
V _L -V _R | look, function G ₁ indicating this value to the following equation 12
To calculate the deceleration coefficient _RG .

[0059]

Equation 12] _{R G = G 1 (| V} L -V R |) Fig. 4 is a diagram showing an example of the function G _1. As shown in FIG. 4, the function G ₁ is the vehicle speed difference | V _L -V _R | When larger, the deceleration coefficient R _G is set to be smaller.

Next, the command vehicle speed V _L of right and left wheels, by substituting V _R and the deceleration coefficient R _G to a function H _1, H ₂ shown in the following Expression 13, the correction command vehicle speed V _L of the left wheel 'and the right wheel Correction command vehicle speed V
Calculate _R '.

[0061]

V _L ′ = H ₁ (V _L , R _G ) V _R ′ = H ₂ (V _R , R _G ) The functions H ₁ , H ₂ are represented by V _L ′ <V _L , V _R ′ < is set in such a way that V _R. An example of the functions H ₁ and H ₂ is shown in Expression 14 below.

[0062]

V _L ′ = V _L × (k × R _G ) V _R ′ = V _R × (k × R _G ) In Equation 14, k is a constant, and k = 1 may be set.

[0063] command vehicle speed V _L of right and left wheels with the number 14, V _R the correction command vehicle speed V _L ', V _R' be corrected to, the relationship of the number 8, the travel turning radius R _C change do not do. Therefore, the speed is reduced without changing the traveling course.

It should be noted that the function G ₁ corresponds to 0 shown in FIG.
≦ | V _L -V _R | in the range of _{≦ d1, V L '= V} L, V R' =
It is set such that V _R. This means that a handicapped occupant can use the delicate joystick 11 as he wishes.
Can not be operated, for example, because he wants to go straight, he tries to operate the joystick 11 forward, but if he operates a little in the left and right direction contrary to his will, the command vehicle speed difference between the left and right wheels occurs, This is to prevent the commanded vehicle speed from being decelerated and corrected to deteriorate the ride quality.

Returning to FIG. 1, the commanded vehicle speed correction calculator 7
4 is the calculated left and right wheel correction command vehicle speed V _L ′, V
_When the absolute value of _R ′ exceeds a preset maximum speed Vmax, the maximum speed Vmax is limited. That is, if the calculated left-wheel correction command vehicle speed V _L ′ is | V _L '|> Vmax, | V _L ' | = Vmax, and the calculated right-wheel correction command vehicle speed V _R 'is | V _R '. |> Vmax if, | V _R '| = Vmax
And

The command vehicle speed correction calculator 74 monitors the actual vehicle speeds v _L and v _R input from the vehicle speed calculator 73 in order to limit the vehicle speed of the left and right wheels to the maximum speed Vmax.

The command vehicle speed correction calculation unit 74 outputs the IF6 when the calculation result of the correction command vehicle speeds V _L ′, V _R ′ for the left and right wheels is 0, that is, when both or any of the driving wheels are stopped.
3, an off signal is output to the relays 4L and 4R to be stopped to turn off the relays, and the corresponding motors 3L and 3R are turned off.
The current supply to R is cut off and stopped. On the other hand, the correction command vehicle speed V _L of left and right wheels ', V _R' when the calculation result of the non-zero, the corresponding relay 4L through IF63, and outputs an ON signal is turned on 4R.

The PWM wave calculator 75 calculates the actual vehicle speeds v _L and v _R input from the vehicle speed calculator 73 and the command vehicle speed correction calculator 7.
Correction command vehicle speed V _L of right and left wheels inputted from 4 ', V _R' from the corrected command speed and the actual vehicle speed deviation (V _L '-v _L),
(V _R '-v _R) is calculated and the function D _L shown in the following Expression 15, D
_The duty ratios K _L and K _R are calculated using _R.

[0069]

K _L = D _L (V _L ′, Δ (V _L ′ −v _L )) K _R = D _R (V _R ′, Δ (V _R ′ −v _R )) The above functions D _L , D _R is set so that a duty ratio corresponding to the correction command vehicle speed and a deviation between the correction command vehicle speed and the actual vehicle speed is obtained.

Then, the PWM wave calculator 75 outputs the
And outputs a PWM wave control signal corresponding to the duty ratios K _L and K _R to the motor control units 5L and 5R via the
The drive current level supplied to L and 3R is controlled. Thus, the rotation speeds of the motors 3L and 3R, that is, the vehicle speeds of the left and right drive wheels are controlled.

Next, the operation of the first embodiment will be described with reference to FIG. FIG. 5 is a flowchart illustrating the operation procedure of the first embodiment.

First, the forward and backward components and the left and right components of the tilt angle are calculated from the tilt angle signal of the joystick 11 and input to the command vehicle speed calculator 72 (step S1), and then the command vehicle speeds V _L and V of the left and right wheels. _R is calculated (step S2), and the absolute value of the vehicle speed difference from the calculated value | V _L -V _R | is calculated (step S3), and the absolute value using a deceleration coefficient R _G is calculated (step S4) , the command vehicle speed V _L, V _R
And correction command vehicle speed V _L of right and left wheels with the reduction factor R _G ',
V _R 'is calculated (step S5).

Next, the actual vehicle speeds v _L and v _{R of} the left and right wheels are calculated (step S6), and then the deviation (V _L '-v _L ), (V _R ' -v _R ) between the correction command vehicle speed and the actual vehicle speed. ) Is calculated (step S7), and using these, the duty ratios K _L ,
K _R is calculated (step S8), and the duty ratio K _L, PWM wave control signal corresponding to K _R is output (step S9).

Then, if the system ends, that is, if the main switch 12 is turned off (YE in step S10)
S), the process ends, and if the main switch 12 is not turned off (NO in step S10), the process returns to step S1 and the above operation is repeated.

[0075] Thus, according to the first embodiment, the command vehicle speed V _L of right and left wheels, the V _R, the absolute value of the vehicle speed difference | V _L -
Since the correction command vehicle speeds V _L ′ and V _R ′ are reduced in accordance with V _R |, the ride comfort is prevented from deteriorating even when the joystick 11 is turned at the maximum speed by operating the tilt angle of the joystick 11. can do. Also, each command vehicle speed V _L, V _R
Is corrected so that the traveling turning radius does not change, so that the operation of the joystick 11 and the actual traveling of the electric wheelchair can be matched, thereby preventing a decrease in operability.

[0076] Incidentally, the speed reduction factor R _G is, instead of obtaining by calculation using the function G ₁ as described above, stores the table data created in advance in the memory 8, the absolute value of the vehicle speed difference May be determined by referring to this table data.

FIG. 6 is a block diagram showing a control configuration of a second embodiment of the electric wheelchair to which the present invention is applied. The same components as those in the first embodiment are denoted by the same reference numerals,
Only the differences will be described.

In the second embodiment, the joystick input unit 71 also outputs the left-right component of the tilt angle of the joystick 11 to the command vehicle speed correction calculation unit 74.

[0079] Then, the command vehicle speed correction calculation unit 74, the absolute value of the vehicle speed difference between the left and right wheels | V _L -V _R | in place, the following number of absolute values of the horizontal direction component of the tilt angle of the joystick 11 1
Substituted into the function G ₂ shown in 6 calculates a deceleration coefficient R _G are.

[0080]

Equation 16] R _G = _{G 2} (| lateral direction component of the tilt angle |) FIG. 7 is a diagram showing an example of the function G _2. As shown in FIG. 7, the function G ₂ is the absolute value of the horizontal direction component of the tilt angle of the joystick 11 is large, the deceleration coefficient R _G is set to be smaller. Similar to the function G ₁ shown in FIG. _{4, 0 ≦ | V L -V} R | in the range of _{≦ D1, V L '= V} L, V R' is set to be = V _R I have.

Even in this case, the absolute value of the vehicle speed difference between the left and right wheels |
Since V _L -V _R | is determined only by the absolute value of the left-right component of the tilt angle of the joystick 11, the deceleration coefficient _RG can be similarly obtained. Accordingly, as in the first embodiment, the traveling turning radius R _C does not change, and the vehicle is decelerated without changing the traveling course.

Next, the operation of the second embodiment will be described with reference to FIG. FIG. 8 is a flowchart illustrating the operation procedure of the second embodiment.

Steps S21 and S22 are the same as steps S1 and S2 in FIG. Following step S22, the joystick 11 calculated in step S21
The deceleration coefficient R is calculated using the absolute value of the horizontal component of the tilt angle of
_G is calculated (step S23). Subsequent step S2
Steps S4 to S29 are the same as steps S5 to S10 in FIG.

[0084] Thus, according to the second embodiment, the command vehicle speed V _L of right and left wheels, the V _R, corrected command vehicle speed V _L which is decelerated in accordance with the absolute value of the horizontal direction component of the tilt angle of the joystick 11 ' , V _R ′, it is possible to prevent the ride quality from deteriorating even when the vehicle is turning while operating the joystick 11 at the maximum inclination angle. Also, each command vehicle speed V _L, the V _R, since the travel turning radius is corrected so as not to be changed, it is possible to align the running of the actual electric wheelchair and operation of the joystick 11, whereby, the operability The drop can be prevented.

[0085] Incidentally, the speed reduction factor R _G is, instead of obtaining by calculation using the function G ₂ as described above, stores the table data created in advance in the memory 8, the absolute value of the vehicle speed difference May be determined by referring to this table data.

FIG. 9 is a block diagram showing a control configuration of a third embodiment of the electric wheelchair to which the present invention is applied. The same components as those in the first embodiment are denoted by the same reference numerals,
Only the differences will be described.

The third embodiment is different from the first embodiment in that
A left / right component weighting calculation unit 76 is newly provided between the joystick input unit 11 and the command vehicle speed calculation unit 72, while the command vehicle speed correction calculation unit 74 is removed.

The left / right component weight calculation unit 76 substitutes the left / right component of the tilt angle calculated by the joystick input unit 71 into the function f shown in the following equation 17 for correction. At the same time, it outputs the correction value and the longitudinal component to the command vehicle speed calculation unit 72.

The command vehicle speed calculation unit 72 calculates the functions F ₁ and F from the correction value of the left-right component of the tilt angle obtained by the left-right component weight calculation unit 76 and the front-back direction component as shown in the following equation (17). _The command vehicle speeds V _L and V _R are calculated by 2 and the calculated values are output to the PWM wave calculator 75.

[0090]

Equation 17] V _L = F ₁ (front-rear direction component of the tilt angle, f (horizontal direction component) of the tilt angle) (the left-right direction component of the front-rear direction component, f (tilt angle tilt angle)) V _R = F ₂ The function f is set so that the weight of the tilt angle of the joystick 11 in the left-right direction component is made lower than that in the front-back direction component. Lateral direction component of the tilt angle, the command vehicle speed V _L of right and left wheels, the vehicle speed difference V _R | V _L -V _R | is intended to cause, by the function f, the vehicle speed difference |
V _L −V _R | will be reduced.

The command vehicle speed calculation unit 72 has a command vehicle speed maximum speed Vmax limiting function that the command vehicle speed correction calculation unit 74 of the first embodiment has, and the actual vehicle speed v _L input from the vehicle speed calculation unit 73. It has a function of monitoring v _{R and} a function of outputting ON / OFF signals to the relays 4L and 4R.

Next, the operation of the third embodiment will be described with reference to FIG. FIG. 10 is a flowchart illustrating the operation procedure of the third embodiment.

Step S41 is the same as step S41 in FIG.
Same as 1. Following step S41, step S41
The weighting of the horizontal component is performed by substituting the horizontal component of the tilt angle of the joystick 11 calculated in 41 into the function f (step S42).

[0094] Then, results of the weighting calculation, and a front-rear direction component of the tilt angle of the joystick 11, command vehicle speed V _L of right and left wheels, V _R is calculated (step S43),
The actual vehicle speeds v _L and v _{R of the} left and right wheels are calculated (step S4).
4) Then, the deviation (V _L −v _L ) between the commanded vehicle speed and the actual vehicle speed,
(V _R -v _R) is calculated (step S45).

The following steps S46 to S48 correspond to the steps shown in FIG.
Are the same as steps S8 to S10.

As described above, according to the third embodiment, the weight of the tilt angle of the joystick 11 with respect to the left-right component is set lower than the front-rear component, and is substituted into the functions F ₁ and F _2. speed difference command vehicle speed V _L, V _R of wheels | V _L -V _R | is reduced, thereby, even when turning by operating the tilting angle of the joystick 11 to the maximum speed, prevent the ride comfort deterioration can do. Further, since only the weighting of the tilt angle in the left-right direction component is reduced, the calculation time of the CPU 7 can be reduced, and the control can be realized by a control program having a simple configuration.

Next, a fourth embodiment of the electric wheelchair to which the present invention is applied will be described. Although the control configuration of the fourth embodiment is the same as that of the first embodiment shown in FIG. 1, the correction procedure of the command vehicle speed correction calculation unit 74 is different, and this difference will be described.

The command vehicle speed correction calculation section 74 calculates the centrifugal acceleration G of the vehicle according to the procedure described below, and if the value exceeds the preset set value Gmax, the centrifugal acceleration G is set to the above set value. value command vehicle speed V _L of right and left wheels so as to Gmax, V _R correction command vehicle speed correcting the V _L ', V _R' and calculates a.

[0099] That is, first, the command vehicle speed V _L of right and left wheels which is calculated by the command vehicle speed calculation unit 72, by using the V _R, the number 5
By calculates the velocity V _C of the vehicle, calculates a travel turning radius R _C of the vehicle by the number 8.

[0100]

G = (V _C ) ² / R _C Next, the centrifugal acceleration G of the vehicle is calculated by the above Expression 18 using the vehicle speed V _C and the vehicle turning radius R _C. It can be seen from Equation 1 that the centrifugal acceleration G is calculated from Equation 18 above.

Then, the calculated centrifugal acceleration G is G>
In the case of Gmax, the corrected command vehicle speed V _L ′,
'It is calculated, and when the _{G ≦ Gmax, V L' V} R = V L, V R '=
V _R.

[0102]

Equation 19] _{V L '= √ (Gmax /} G) × V L V R' = √ (Gmax / G) × V R The above setting value Gmax is the maximum value that does not impair the riding comfort when the turning Is set to

[0103] In the fourth embodiment, the command vehicle speed of the left and right wheels by using the number 19 V _L, V _R the correction command vehicle speed V _L ', V _R'
, The traveling turning radius R _{C is obtained} from the relationship of the above equation (8).
Does not change. Therefore, similarly to the first embodiment, the vehicle is decelerated without changing the traveling course.

Next, the operation of the fourth embodiment will be described with reference to FIG. FIG. 11 is a flowchart illustrating an operation procedure according to the fourth embodiment.

Steps S61 and S62 are the same as steps S1 and S2 in FIG. Following step S62, by using the command vehicle speed V _L, V _R of the left and right wheels calculated at step S62, the travel turning radius R _C and the velocity V _C of the vehicle of the vehicle is calculated (step S63, S64).

Next, the centrifugal acceleration G is calculated using the turning radius R _C and the speed V _C of the vehicle (step S).
65), the magnitude of the centrifugal acceleration G and the set value Gmax is determined (step S66). And G ≦ Gmax
If (NO in step S66), the process proceeds to step S68, while if G> Gmax (Y in step S66)
ES), correction command vehicle speed V _L ', V _R' is calculated (step S67), the process proceeds to step S68.

The following steps S68 to S72 correspond to the steps shown in FIG.
Are the same as steps S6 to S10.

[0108] Thus, according to the fourth embodiment, as in centrifugal acceleration G of the vehicle is less than or equal to the specified value Gmax, command vehicle speed V _L of right and left wheels, V _R the correction command vehicle speed V _L ', V _R Therefore, even when the joystick 11 is turned at the maximum speed by operating the tilt angle of the joystick 11, it is possible to prevent the ride quality from deteriorating. Also, each command vehicle speed V _L, V _R
Is corrected so that the traveling turning radius does not change, so that the operation of the joystick 11 and the actual traveling of the electric wheelchair can be matched, thereby preventing a decrease in operability.

Note that the third embodiment may be added to the first embodiment or the second embodiment.
That is, the command vehicle speed V _L of right and left wheels obtained in the third embodiment, the V _R, command vehicle speed V _L of right and left wheels in the first embodiment or the second embodiment may be used as V _R. In this case, the command vehicle speed calculation unit 72 in FIG. 1 or FIG. 6 may calculate the weight of the left-right component of the tilt angle of the joystick 11.

[0110]

As described above, according to the first aspect of the present invention, the command wheel of each drive wheel instructed according to the operation amount of the first operation and the operation amount of the second operation of the operation means. Since the correction to reduce the absolute value of each command wheel speed is performed according to the magnitude of the absolute value of the speed difference, the difference between the command wheel speeds of the respective drive wheels indicated by the operation performed by the operating means is calculated. When the absolute value is large, that is, when the traveling turning radius of the vehicle is small, each command wheel speed is corrected to be small, whereby the centrifugal force generated in the vehicle can be reduced. Comfort can be prevented from deteriorating.

Further, according to the invention of claim 2, the vehicle speed is controlled by using the command wheel speeds of the respective drive wheels specified according to the operation amount of the first operation and the operation amount of the second operation of the operation means. Since the centrifugal acceleration is calculated and the command wheel speed of each drive wheel is corrected so that this centrifugal acceleration matches a preset value, when the traveling turning radius of the vehicle is small due to the operation performed by the operation means. However, the centrifugal acceleration generated in the vehicle can be maintained at or below the set value, and the reduction in ride comfort of the vehicle can be reliably prevented.

According to the third aspect of the present invention, the command wheel speed of each drive wheel is designated by reducing the weight of the operation amount of the second operation as compared with the operation amount of the first operation. Therefore, the absolute value of the difference between the commanded wheel speeds of the respective drive wheels is reduced as compared with the amount of operation performed by the operating means, and the traveling turning radius of the vehicle is not reduced, so that a large centrifugal force is generated in the vehicle. , And a reduction in ride comfort can be more reliably prevented.

According to the fourth aspect of the present invention, the command wheel speed of each drive wheel is corrected so that the traveling turning radius of the vehicle does not change due to the operation performed by the operation means. Can be prevented, and the ride comfort of the vehicle can be prevented from being lowered.

[0114]

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control configuration of a first embodiment of an electric wheelchair to which the present invention is applied.

FIG. 2 is an explanatory diagram showing a tilt direction and a tilt angle of a joystick 11;

FIG. 3 shows a joystick 11 as shown in FIG.
Is rotated from the front (+) of the front-rear direction component to the right (+) of the left-right direction component at the maximum tilt angle, the left wheel speed V _L , the right wheel speed V _R , and the left and right with respect to the value X of the left and right direction component Wheel speed difference (V _L -V _R ) and vehicle speed V _C = (V _L + V _R )
FIG.

4 is a diagram showing an example of the function G _1.

FIG. 5 is a flowchart showing an operation procedure of the first embodiment.

FIG. 6 is a block diagram showing a control configuration of a second embodiment of the electric wheelchair to which the present invention is applied.

7 is a diagram showing an example of the function G _2.

FIG. 8 is a flowchart illustrating an operation procedure according to the second embodiment.

FIG. 9 is a block diagram showing a control configuration of a third embodiment of the electric wheelchair to which the present invention is applied.

FIG. 10 is a flowchart illustrating an operation procedure according to the third embodiment.

FIG. 11 is a flowchart showing an operation procedure of the fourth embodiment.

FIG. 12 is a schematic diagram illustrating speeds and turning radii of drive wheels when the vehicle turns.

[Explanation of symbols]

Reference Signs List 1 operation panel 11 joystick (operation means) 12 main switch 2 power supply unit 3L, 3R motor (left driving means, right driving means) 31L, 31R vehicle speed sensor 4L, 4R relay (left driving means, right driving means) 5L, 5R motor Control unit (left drive unit, right drive unit) 6 control board 7 CPU 71 joystick input unit 72 command vehicle speed calculation unit 73 vehicle speed calculation unit 74 command vehicle speed correction calculation unit (correction unit, acceleration calculation unit, comparison unit, radius calculation unit) 75 PWM wave calculation unit (drive control means) 76 Left and right component weight calculation unit (operation means) 8 memory

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60L 15/00-15/20 A61G 5/00-5/04

Claims (4)

(57) [Claims] In a vehicle provided with left driving means for rotating a left driving wheel and right driving means for rotating a right driving wheel, the left and right driving wheels are rotated in the same direction at the same wheel speed. A first operation to rotate the left and right driving wheels in a direction opposite to each other at a predetermined wheel speed.
Operation is possible either alone or simultaneously, and operating means for instructing the command wheel speed of each drive wheel according to the operation amount of each of the operations, Correction means for performing a correction to reduce the absolute value of each of the command wheel speeds in accordance with the magnitude of the absolute value of the difference; and the left driving means for rotating the drive wheels at the corrected command wheel speeds And a drive control means for controlling the right drive means , wherein the correction means comprises a command wheel speed of each drive wheel.
The absolute value of each command wheel speed decreases as the absolute value of the difference between
A vehicle speed control device wherein the degree of reduction is increased . 2. A vehicle provided with a left driving means for rotating a left driving wheel and a right driving means for rotating a right driving wheel, wherein the left and right driving wheels are rotationally driven in the same direction at the same wheel speed. A first operation to rotate the left and right driving wheels in a direction opposite to each other at a predetermined wheel speed.
Operation alone or simultaneously is possible, the operating means for instructing the command wheel speed of each drive wheel according to the operation amount of each operation, the command wheel speed of each instructed drive wheel Acceleration calculating means for calculating the centrifugal acceleration of the vehicle using the comparing means for comparing the calculated centrifugal acceleration with a preset value; and when the centrifugal acceleration is greater than the set value, the centrifugal acceleration Correction means for correcting the command wheel speeds of the respective drive wheels so as to match the set values, and the left drive means and the right drive means for rotating the respective drive wheels at the corrected command wheel speeds. And a drive control means for controlling the vehicle speed. 3. The operation means for instructing each of the command wheel speeds by reducing the weight of the operation amount of the second operation compared to the operation amount of the first operation. The vehicle speed control device according to claim 1 or 2, wherein 4. The vehicle speed control device according to claim 1, wherein a traveling turning radius of the vehicle is calculated using a command wheel speed of each of the drive wheels instructed by the operation means. Means, wherein the correction means corrects the command wheel speed of each of the drive wheels so that the traveling turning radius does not change.