JPH0928737A - Motor-driven wheelchair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheelchair capable of being quickly stopped in the case that one of the wheels, right or left, is locked. SOLUTION: Right and left wheels of a wheelchair are separately driven by electric motors 3, 4. The motor-driven wheelchair is provided with a joy stick 1b steered by the driver, a CPU 12 for a drive control, and vehicle speed sensors 3a, 4a detecting actual rotational speeds of the wheels. The CPU 12 calculates the command rotational speeds for the individual wheels to control the motors 3, 4 based on the tilt angle signal issued from the joy stick 1b. Also, the CPU 12 calculates the actual wheel speeds from the results the detection by the wheel speed sensors 3a, 4a, and judges it based on the command rotational speeds and actual rotational speeds whether or not one of the wheels, right or left, is locked. And when the CPU judges that one of the wheels is locked, it switches off the wheel relays 7, 8, supplying the motors 3, 4 with electric current for both right and left wheels to stop running.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an electric wheelchair capable of automatically traveling in which left and right wheels are separately driven by electric driving means.

[0002]

2. Description of the Related Art Generally, in an electric wheelchair, a joystick is used as a steering means and the rotation speed of the left and right wheels is controlled by tilting the joystick back and forth and left and right.
For example, when the occupant tilts the joystick back and forth, the electric wheelchair is moved forward and backward, and the speed at that time is controlled.When the joystick is tilted left and right, the wheels on the left and right rotate at different speeds, and The direction can be changed.

[0003]

By the way, in the above-mentioned electric wheelchair, some malfunction or
Disturbances can lock the wheels and prevent them from rotating at the commanded speed. In such a case, to continue running,
It wastes electric power, is not efficient, and puts a heavy load on the motor, which shortens its life. Furthermore, especially when only one wheel is locked, the electric wheelchair moves in a direction that the occupant does not expect, and it is difficult to move the electric wheelchair in a desired direction. When one of the wheels is locked in this way, the electric wheelchair should be stopped, but the occupant of the electric wheelchair cannot always stop immediately. In addition, when the electric wheelchair is parked or parked, the wheels are normally stopped by mechanical brakes, but even if the occupant forgets to release one brake, the wheels lock. The same problem occurs as described above.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electric wheelchair capable of promptly stopping when either one of the left and right wheels is locked.

[0005]

In order to solve the above-mentioned problems, in an electric wheelchair according to the present invention, in an electric wheelchair in which left and right wheels are rotated by separate electric drive means, a steering operation operated by a user. Means, and a command vehicle speed calculation means for calculating a command rotation speed of each wheel based on a signal emitted from the steering means, and a speed control means for controlling each electric drive means based on the command rotation speed,
Real vehicle speed calculating means for calculating the actual rotation speed of each wheel, and one-wheel lock detection for determining whether one of the left and right wheels is locked based on the command rotation speed and the actual rotation speed of each wheel Means and stop means for stopping rotation of both the left and right wheels when the one-wheel lock detection means determines that one of the wheels is locked.

The one-wheel lock detecting means detects the speed deviation Δω _L of the left wheel, which is the absolute value of the difference between the command rotation speed ω _Li of the left wheel and the actual rotation speed ω _La of the left wheel, and Calculate the right wheel speed deviation Δω _R , which is the absolute value of the difference between the wheel command rotation speed ω _Ri and the right wheel actual rotation speed ω _Ra , and the difference ΔΩ between both speed deviations Δω _L and Δω _R. , The difference Δ
It is more preferable that one of the left and right wheels is determined to be locked when Ω is out of the predetermined range for a predetermined time.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. A. First Embodiment (1) Configuration of Embodiment First, FIG. 1 is a block diagram showing a control circuit of an electric wheelchair according to an embodiment of the present invention. In the figure, reference numeral 1 is an occupant operation panel, 2 is a power source such as a storage battery, 3 and 4 are motors (electrical driving means) for rotating the left and right wheels, and 5 and 6 are the rotations of the motors 3 and 4. It is a motor control unit.
Each of the motors 3 and 4 is provided with a vehicle speed sensor 3a or 4a for detecting their rotation speed. further,
Relays (stopping means) 7, 8 are provided in the respective motor control units 5, 6.
The electric current is supplied via the motors. When the relays 7 and 8 are turned off, the motors 3 and 4 are stopped. In the illustrated state, the relays 7 and 8 are off.

Reference numeral 9 is a warning light made of an LED, 10 is a warning buzzer, and these warning lights 9 and 10 are shown.
Is provided to inform the occupant that either the left or right wheel is locked. Reference numeral 11 denotes a controller, which is configured by a CPU (central processing unit: commanded vehicle speed calculation means, speed control means, actual vehicle speed calculation means, one-wheel lock detection means) 12, hardware such as memory. There is.

The operation panel 1 is provided with a main switch 1a for opening and closing a circuit for supplying a current to the controller 11. Further, the operation panel 1 is provided with a joystick (speed control operator: steering means) 1b for forward / backward operation of each wheel and speed control. When the occupant tilts the joystick 1b, the joystick 1b outputs a voltage according to the tilt angle.

The CPU 12 has an input interface 27.
Various signal outputs and switch outputs are fetched from a to 27d, and the CPU 12 controls the output interface 27
Control signals such as various command values are output from e and 27f to the outside. The CPU 12 operates based on a predetermined program and performs various functions. In the figure, the blocks are displayed on the assumption that the joystick input unit 13, the command vehicle speed calculation unit 14, etc. are provided for each of these functions, and the function of each block will be described below. The functions of the CPU 12 may be performed by hardware.

The voltage output from the joystick 1b is analog / digital converted by the input interface 27a and input to the joystick input unit 13. The joystick input unit 13 outputs a tilt angle signal based on the digitally converted voltage value. In this way, the tilt angle signal has a value corresponding to the tilt angle of the joystick 1b. Further, the tilt angle signal has a positive value when the joystick 1b is tilted forward and a negative value when the joystick 1b is tilted backward.

The command vehicle speed calculator 14 calculates the speed at which each wheel should be rotated based on the tilt angle signal from the joystick input unit 13, and outputs command vehicle speed signals for the left and right wheels. The PWM wave calculation unit 15 outputs a PWM wave serving as a control signal based on the command vehicle speed signal, and controls the current value given to the left and right motor control units 5 and 6. As a result, the drive currents given to the motors 3 and 4 from the motor control units 5 and 6 are controlled, and the rotation speed of the motors 3 and 4, that is, the speed of each wheel is controlled. The vehicle speed calculation unit 16 receives the vehicle speed detection signals input from the vehicle speed sensors 3a and 4a,
The actual speeds of the left and right wheels are calculated, and the actual vehicle speed signal is output. The PWM wave calculator 15 takes in the actual vehicle speed signal and feedback-controls the current value.

The one-wheel lock detection / calculation unit 20 locks one of the wheels based on the command vehicle speed signals of the left and right wheels from the command vehicle speed calculation unit 14 and the actual vehicle speed signals of the left and right wheels from the vehicle speed calculation unit 16. Judge whether or not. When it is determined that one of the wheels is locked, the one-wheel lock detection / calculation unit 20 sets P to stop both wheels.
The command vehicle speed = “0” signal is output to the WM wave calculation unit 15, and an OFF signal is output to both the relays 7 and 8. Further, the one-wheel lock detection calculation unit 20 outputs an ON signal to the LED lighting control unit 21 and the buzzer control unit 22.

LED lighting control unit 21 and buzzer control unit 2
2 turns on the warning light 9 according to the ON signal from the one-wheel lock detection calculation unit 20, and outputs the warning buzzer 10 respectively.
Generate a warning sound. Further, the timer 23 outputs a signal corresponding to time, and the time counting section 24 outputs an elapsed time signal based on this signal. The elapsed time signal is input to the one-wheel lock detection / calculation section 20 and is used for determining whether or not one of the wheels is locked.

(2) Operation of Embodiment Next, FIG. 2 is a flowchart showing the operation of this embodiment. The operation of this embodiment will be described with reference to FIG. First, the occupant operates the operation panel 1 for the occupant to turn on the main switch 1a. As a result, a current is supplied to the controller 11 to enable the controller 11 to operate, and the motor control units 5 and 6 enter the standby state to enter the system activation state.

When the occupant tilts the joystick 1b, a tilt angle signal is output from the joystick input unit 13 in accordance with the tilt angle, and the tilt angle signal is
It is input to the command vehicle speed calculator 14 (step S1). Based on this tilt angle signal, the command vehicle speed calculation unit 14 calculates the command vehicle speed ω _Li for the left wheel and the command vehicle speed ω _Ri for the right wheel, and outputs a command vehicle speed signal corresponding thereto (step S2). ). Based on this command vehicle speed signal, the PWM wave calculation unit 15 controls the current value given to the left and right motor control units 5 and 6. As a result, the drive currents given to the motors 3 and 4 from the motor control units 5 and 6 are controlled, and the rotation speed of the motors 3 and 4, that is, the speed of each wheel is controlled. With this control, if the wheels rotate at equal speeds, the electric wheelchair goes straight (including forward and reverse), and if the left and right wheels rotate at different speeds, the direction of travel of the electric wheelchair changes. It

When the wheels are actually driven, the vehicle speed calculation unit 16 calculates the actual vehicle speed ω _La of the left wheel and the actual vehicle speed ω _Ra of the right wheel, and outputs the actual vehicle speed signal corresponding thereto. Output (step S3). These vehicle speed ω _Li ,
The command vehicle speed signal and the actual vehicle speed signal corresponding to ω _Ri , ω _La, and ω _Ra are input to the PWM wave calculator 15 and the one-wheel lock detection calculator 20. One wheel lock detection calculation unit 20
Calculates the speed deviation Δω _L of the left wheel and the speed deviation Δω _R of the right wheel from Expression (1) and Expression (2) from the command vehicle speed signal and the actual vehicle speed signal (step S4). Δω _L = | ω _Li −ω _La | (1) Δω _R = | ω _Ri −ω _Ra | (2) These Δω _L and Δω _R are also shown in FIG.

Next, the one-wheel lock detection / calculation section 20 obtains the left-right difference ΔΩ of the speed deviation by the equation (3) (step S5). ΔΩ = | Δω _L −Δω _R | (3) Then, the process proceeds to step S6, where the one-wheel lock detection calculation unit 20 determines whether ΔΩ is equal to or more than the set value, and ΔΩ is equal to or more than the set value. If not, the process proceeds to step S7 to control the normal running described later. On the other hand, if ΔΩ is equal to or larger than the set value in step S6, the process proceeds to step S8, and it is determined whether or not the state where ΔΩ is equal to or larger than the set value continues for a predetermined time (t) or longer. Then, in step S8, if the state in which ΔΩ is equal to or more than the set value does not continue for the predetermined time (t) or more, the process also proceeds to step S7 to control the normal traveling.

In the normal traveling control of step S7, the PW
The M-wave calculation unit 15 matches the actual vehicle speed ω _La of the left wheel with the command vehicle speed ω _Li to the left wheel, and the actual vehicle speed ω _Ra of the right wheel and the command to the right wheel. The current values given to the motor control units 5 and 6 are adjusted so as to match the vehicle speed ω _Ri . As a result, the electric wheelchair advances in a desired direction at a speed desired by the occupant.

After that, the process proceeds to step S9, and it is determined whether or not the main switch 1a is turned off. If the main switch 1a is turned off, the current supplied to the controller 11 is shut off and the system does not operate. It becomes a state.
That is, when the passenger wants to stop traveling of the electric wheelchair, the main switch 1a is turned off. On the other hand, step S
In 9, if the main switch 1a is not turned off,
Returning to step S1 described above, the traveling control of the electric wheelchair is continued.

In step S8 described above, ΔΩ
When the state where the value is equal to or more than the set value continues for a predetermined time (t) or more, it is determined that one wheel is locked, and step S1 is performed.
Go to 0. This will be described with reference to FIG.
For example, when the left wheel locks for some reason, the actual vehicle speed ω _La of the left wheel decreases to "0" or significantly. As a result, the speed deviation Δω _L of the left wheel becomes extremely large, and the difference ΔΩ between the speed deviations Δω _L and Δω _R of both wheels becomes extremely large, exceeding the predetermined range. Then, if this state continues for a predetermined time (t),
Judge that one wheel is locked.

In step S10, the one-wheel lock detection / calculation section 20 outputs a signal of the command vehicle speed = "0".
When this command vehicle speed = “0” signal is input, the PWM wave calculation unit 15 controls the current value given to each of the left and right motor control units 5 and 6 to “0”. As a result, the drive currents given to the motors 3 and 4 from the motor control units 5 and 6 are reduced, and the rotation of the motors 3 and 4, that is, the rotation of each wheel is decelerated. At the same time, the one-wheel lock detection calculation unit 20 outputs an off signal to both the relays 7 and 8. As a result, the currents supplied from the relays 7 and 8 to the motor control units 5 and 6 are cut off, the motors 3 and 4 are stopped, and the rotation speed of each wheel is completely set to "0". In this way, the electric wheelchair is forcibly stopped.

Next, the one-wheel lock detection / calculation unit 20 uses L
An ON signal is output to the ED lighting control unit 21 and the buzzer control unit 22 (step S11). As a result, the warning light 9 is turned on and the warning buzzer 10 emits a warning sound. In this way, the occupant is notified that either the left or right wheel is locked.

Thereafter, the process proceeds to step S12, it is determined whether or not the main switch 1a is turned off. If the main switch 1a is not turned off, the process returns to step S10,
Forced stop of the electric wheelchair and lighting of the warning light 9,
The warning sound generation state of the warning buzzer 10 is continued. on the other hand,
In step S12, if the main switch 1a is turned off, the current supplied to the controller 11 is cut off and the system becomes inoperative. As a result, the forced stop state of the electric wheelchair, the lighting of the warning light 9, and the warning sound generation state of the warning buzzer 10 are released. In this state, the occupant or caregiver of the electric wheelchair can check whether or not the wheels are locked due to some malfunction / disturbance or mechanical brake. Then, after removing the cause of such a lock, the main switch 1a is turned on again to restart the traveling of the electric wheelchair.

(4) Summary As described above, according to the present embodiment, when one of the left and right wheels is locked, the one-wheel lock detection / calculation unit 20.
However, by outputting an OFF signal to both the relays 7 and 8, it is possible to forcibly and quickly stop the electric wheelchair. Therefore, while one wheel is locked,
It is possible to prevent the electric wheelchair from advancing in an unexpected direction of the occupant operating the vehicle. Further, by stopping the electric wheelchair when one of the wheels is locked, and turning on the warning light 9 and generating an alarm sound by the warning buzzer 10, the user can be informed that the wheel is locked. As a result, it is possible to suppress the waste of electric power and to remove the excessive load on the motors 3 and 4.

Further, at this time, the electric wheelchair is stopped by turning off the relays 7 and 8 and stopping the current supply to the motors 3 and 4.
Immediately after locking one of the wheels, it is possible to suppress the waste of electric power and remove an excessive load applied to the motors 3 and 4. Moreover, the detection of the lock of one wheel as described above is performed by operating the CPU 12 based on a predetermined program, and the CPU 12 judging from the actual vehicle speed and the command vehicle speed. Therefore, a special detection circuit or the like for determining whether or not the wheels are locked is unnecessary, and the electric wheelchair can be manufactured at low cost.

Further, according to the present embodiment, as shown and described in step S8 of FIG. 2 and FIG. 3, the state in which the actual rotation speed of each wheel deviates from the predetermined range continues for the predetermined time (t). Only then is it determined that one of the wheels is locked. Therefore, it is possible to avoid the inconvenience that the occupant feels annoyed because the electric wheelchair is frequently stopped only by temporarily reducing the speed of one wheel. Further, in the present embodiment, when the state where the difference ΔΩ between the speed deviations Δω _L and Δω _R of both wheels deviates from the predetermined range continues for a predetermined time (t), it is determined that one of the wheels has locked. Therefore,
For example, when overcoming a step on the road, the actual rotational speeds of both wheels drop momentarily, and the command rotational speeds ω _Li and ω _Ri deviate from the actual rotational speeds ω _La and ω _Ra for a moment. Does not determine that one wheel is locked. As a result, it is possible to avoid an inconvenience in which the electric wheelchair is frequently stopped and the occupant feels troublesome.

C. Modifications In the above embodiment, the occupant of the electric wheelchair operates the electric wheelchair, but the present invention is not limited to this, and an assistant may operate the electric wheelchair.

[0029]

As described above, according to the first aspect of the present invention, when one of the left and right wheels is locked, the electric wheelchair can be stopped immediately and the wheelchair can be operated. It is possible to prevent the electric wheelchair from advancing in an unexpected direction of the user. Further, by stopping the electric wheelchair when one of the wheels is locked and letting the user notice that the wheelchair is locked, it is possible to suppress the waste of electric power and quickly remove the excessive load on the motor.

According to the second aspect of the invention, one of the wheels is locked only when the difference ΔΩ between the speed deviations Δω _L and Δω _R of both wheels deviates from the predetermined range for a predetermined time. I judge that I did. Therefore, if the actual rotational speeds of both wheels drop significantly and the command rotational speeds ω _Li and ω _Ri deviate greatly from the actual rotational speeds ω _La and ω _Ra for a moment, one of the wheels is locked. Does not judge. As a result, it is possible to avoid the inconvenience that the electric wheelchair frequently stops.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control circuit of an electric wheelchair according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the embodiment.

FIG. 3 is a graph for explaining one-wheel lock detection in the same embodiment.

[Explanation of symbols]

1 operation panel, 1a main switch, 1b joystick (control means), 2 power supply, 3,4 motor (electric drive means), 3a, 4a vehicle speed sensor, 5,6 motor control section, 7,8 relay (stop means) , 9 warning light, 10 warning buzzer, 11 controller, 12 CPU (command vehicle speed calculation means, speed control means, actual vehicle speed calculation means, one wheel lock detection means), 13 joystick input section, 14 command vehicle speed calculation section, 15 PWM wave Calculation unit, 16 vehicle speed calculation unit, 20 one wheel lock detection calculation unit, 21 LED lighting control unit, 22 buzzer control unit, 23 timer, 24 time counting unit, 27a to 27d input interface, 27e, 17f output interface

Claims (2)

[Claims] 1. An electric wheelchair in which left and right wheels are rotated by separate electric drive means, and a command rotation speed of each wheel is calculated based on a steering means operated by a user and a signal emitted from the steering means. A command vehicle speed calculating means, a speed control means for controlling each electric driving means based on the command rotation speed, an actual vehicle speed calculating means for calculating an actual rotation speed of each wheel, and a command for each wheel Based on the rotation speed and the actual rotation speed, one wheel lock detection means for determining whether one of the left and right wheels is locked, and when it is determined that one of the wheels is locked by the one wheel lock detection means An electric wheelchair comprising: stop means for stopping rotation of both the left and right wheels. 2. The one wheel lock detecting means is a speed deviation Δω of the left wheel which is an absolute value of a difference between a command rotation speed ω _Li of the left wheel and an actual rotation speed ω _La of the left wheel.
_L and the speed deviation Δω of the right wheel, which is the absolute value of the difference between the command rotation speed ω _Ri of the right wheel and the actual rotation speed ω _Ra of the right wheel.
_R and the difference ΔΩ between both speed deviations Δω _L and Δω _R are calculated, and when the state where the difference ΔΩ is out of the predetermined range continues for a predetermined time, it is determined that one of the left and right wheels is locked. The electric wheelchair according to claim 1, wherein the electric wheelchair is configured as described above.