JP2002017789A - Control device of motor-assisted wheelchair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a motor-assisted wheelchair capable of securely detecting the abnormal operation of various sensors, especially a sensor for discriminating the direction of progress and a speed sensor, and improving the reliability of the operation of a driving force auxiliary device. SOLUTION: The control device logically judges, based on the signals from the sensor for discriminating the direction of progress and the speed sensor before or during the generation of auxiliary driving force, that the operation of the sensors is abnormal if the combination of the signals from the sensors is impossible when the operation is normal. Therefore, the abnormality of the sensors themselves can be securely monitored, and at the same time, the abnormality of the output signals can be also monitored. As a result, such measures as the stoppage of the auxiliary driving force can be taken early when any abnormality is detected, so that the reliability of the driving force auxiliary device of the motor-assisted wheelchair can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric assist wheelchair which assists a user in driving a wheel by generating an auxiliary driving force from an electric motor according to a wheel operating direction, a wheel operating torque and a vehicle speed. It is.

[0002]

2. Description of the Related Art Conventionally, in addition to a manual wheelchair and an electric wheelchair, the basic structure is the same as that of a manual wheelchair, and a driving force auxiliary device including various sensors, an electric motor, and a control device for controlling them is additionally provided. There is an electric assist wheelchair that generates an auxiliary driving force from an electric motor according to a wheel operation direction, a wheel operation torque, a vehicle speed, and the like of a user to assist a user in driving a wheel.

In the above-mentioned electric assist wheelchair, for example, the output shaft of the electric motor is connected to the wheels, the direction of wheel operation of the user is detected by a traveling direction discriminating sensor, and the electric motor is operated in accordance with the operation torque, speed and the like. To assist the wheel drive operation of the driver.

Here, the direction of the wheel operation, the wheel operating torque, the vehicle speed, and the like are detected by sensors. It is desirable to constantly monitor whether these sensors are functioning normally. Detection was performed only.

[0005]

However, it is not always possible to detect an abnormal output or the like due to noise or the like only by an electrical check of each of the above-mentioned sensors, and if the motor is operated based on this abnormal output, the wheel operation by the user will be difficult. There was a problem of causing discomfort. As an example, when a signal indicating that the traveling direction is suddenly changed from the traveling direction discrimination sensor is output during forward traveling, the electric motor generates a reverse driving force, which is similar to the resistance of the forward operation, that is, the same as applying the brake. And the like.

The present invention has been devised to solve the problems of the prior art as described above, and includes various sensors,
In particular, an object of the present invention is to provide a control device for an electric assist wheelchair capable of reliably detecting an abnormality of a traveling direction discrimination sensor and a speed sensor and improving the operation reliability of a driving force assist device.

[0007]

In order to achieve the above object, according to the present invention, an auxiliary driving force is generated from an electric motor in accordance with a wheel operating direction, a wheel operating torque, a vehicle speed, and the like, so that a user can drive a wheel. An electric assist wheelchair control device having an assisting driving force assisting device includes a traveling direction discriminating sensor and a speed sensor, and based on signals from the two sensors before or during generating an assisting driving force. It is determined that the sensor is abnormal. If the combination of signals from the sensors cannot be a normal operation, it is logically determined that the sensor is abnormal, so that not only the sensor itself but also the output signal can be reliably monitored.
Specifically, for example, when the speed detected by the speed sensor when the direction change is detected by the travel direction determination sensor is equal to or higher than a predetermined speed, the travel direction determination sensor is determined to be abnormal, and the speed sensor determines When the change amount of the detected speed is equal to or more than a predetermined amount, it is determined that the speed sensor is abnormal.

[0008]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a configuration of a driving force assisting device 1 of an electric assist wheelchair to which the present invention is applied. Attached to a wheelchair frame not shown,
An electric motor 2 having an output shaft connected to wheels, a driving device 3 for driving and controlling the electric motor 2, a rotational speed of the wheels,
That is, a traveling direction sensor 4 for detecting the traveling direction of the wheelchair,
Detects a pulse synchronized with the wheel, and calculates the wheel speed,
That is, a wheel speed sensor 5 as a vehicle speed sensor for detecting a vehicle speed
A torque sensor 6 for detecting torque applied to wheels,
And a power supply 7.

The traveling direction sensor 4 is composed of, for example, a rotary encoder, and the control unit 1 determines forward / backward based on a change in a pulse signal output from the traveling direction sensor 4. The wheel speed sensor 5 is composed of a normal pulser or the like, and the control device 1 calculates the vehicle speed from the cycle of the output pulse.

Using the driving force assisting device 1 described above, an appropriate assisting driving force is obtained based on output signals from the traveling direction sensor 4, the wheel speed sensor 5, and the torque sensor 6, and the motor 2 is operated to drive the user. It will help the power.

Next, the wheel speed sensor 5 and the traveling direction sensor 4
Will be described with reference to the flowchart of FIG. This is when the electric assist wheelchair is in operation.
This is always performed when determining the vehicle speed and the traveling direction.

First, at step 1, it is determined whether or not the wheel speed pulse from the wheel speed sensor 5 is normal. This is to determine the vehicle speed based on the signal from the wheel speed sensor 5 and determine that the vehicle speed is abnormal when the amount of change from the previous vehicle speed is larger than a predetermined amount, that is, when the speed changes unusually. . This is based on the fact that a pulse is fixed to Lo or Hi in most cases when the wheel speed sensor is abnormal. However, the amount of change also becomes large when the vehicle actually collides with an obstacle or the like or suddenly stops. If it is determined in step 1 that the wheel speed pulse is abnormal, the process proceeds to step 2 to further increase the wheel speed pulse. Analyze, identify the scene,
Wheel speed pulse fail-safe processing such as appropriately controlling the motor 2 or stopping the motor 2 is performed.

On the other hand, if it is determined in step 1 that the wheel speed pulse from the wheel speed sensor 5 is normal, the process proceeds to step 3, where the wheel speed pulse from the wheel speed sensor 5 is equal to or longer than a predetermined cycle (predetermined vehicle speed). Is determined, and if the wheel speed pulse is shorter than the predetermined period, this routine is ended to perform normal control. If the wheel speed pulse is equal to or longer than the predetermined cycle, it is further determined in step 4 whether or not the traveling direction has been switched from forward to backward, for example, from the output signal from the traveling direction sensor 4. In the same manner as described above, this routine ends to perform the normal control. If the traveling direction has been switched from the output signal from the traveling direction sensor 4, that is, the vehicle does not suddenly change direction at a speed higher than the predetermined vehicle speed, and therefore, Step 3,
If it is determined from step 4 that the vehicle has suddenly changed direction at a predetermined vehicle speed or higher, it is determined that the traveling direction sensor 4 is abnormal (step 5), and a fail-safe process (not shown) such as stopping the motor 2 is performed.

That is, the abnormality of the wheel speed sensor 5 is judged from the variation of the output from the wheel speed sensor 5, and the abnormality of the traveling direction sensor 4 is determined by the output signal from the wheel speed sensor 5 and the output from the traveling direction sensor 4. If the combination with the signal cannot be a normal operation, it is logically determined that the sensor is abnormal.

[0016]

As is apparent from the above description, according to the control apparatus for the electric assist wheelchair according to the present invention, the control unit determines whether or not the auxiliary driving force is generated based on the signals from the traveling direction determination sensor and the speed sensor. If the combination of signals from each sensor cannot be used in normal operation, it is possible to logically judge that the sensor is abnormal, and to monitor the abnormality of the sensor itself, and also monitor the abnormality of the output signal. As a result, when an abnormality is detected, measures such as stopping the driving force assist can be performed at an early stage, and the operation reliability of the driving force assist device of the electric assist wheelchair is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a driving force assisting device of an electric assist wheelchair to which the present invention is applied.

FIG. 2 is a flowchart illustrating a sensor abnormality detection processing procedure performed by the electric assist wheelchair control device to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Driving force auxiliary device 2 Electric motor 3 Control device 4 Traveling direction sensor 5 Wheel speed sensor 6 Torque sensor 7 Power supply

Claims (3)

[Claims] An electric assist wheelchair control device including a driving force assisting device for assisting a user in driving a wheel by generating an auxiliary driving force from an electric motor according to a wheel operating direction, a wheel operating torque, a vehicle speed, and the like. An electric assist wheelchair, comprising: a traveling direction determination sensor; and a speed sensor, wherein the abnormality determination of each of the sensors is performed based on signals from the two sensors before or during generation of an auxiliary driving force. Control device. 2. The traveling direction determination sensor determines that the traveling direction determination sensor is abnormal when a speed detected by the speed sensor when a direction change is detected by the traveling direction determination sensor is equal to or higher than a predetermined speed. Item 2. An electric assist wheelchair control device according to item 1. 3. The speed sensor according to claim 1, wherein the speed sensor determines that the speed sensor is abnormal when an amount of change in the speed detected by the speed sensor is equal to or more than a predetermined amount.
3. The control device for an electric assist wheelchair according to claim 1.