JPH06304206A - Motor-driven vehicle - Google Patents

Abstract

PURPOSE:To save a battery power supply by simply detecting and utilizing the operating force of a helper or the like pushing a motor-driven wheel chair. CONSTITUTION:In a motor-driven vehicle propelled by rotating wheels by a driving force of a motor and moved forward and backward by human power, the wheel 30 is supported rotatably, through a fixed shaft 31, by a vehicle body 2, and an operating force detecting unit 21 for detecting man's operating force so as to generate an electric signal corresponding to the operating force is attached on the fixed shaft 31. A converting unit for generating a drive signal of the motor on the basis of the electric signal of the operating force detecting unit is equipped, and a control unit for controlling the output of the motor by means of the drive signal of the converting unit is equipped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle such as an electric wheelchair, which is driven by a driving force of a motor and can be moved forward or backward by an operation force of a person such as a caregiver. Regarding the vehicle.

[0002]

2. Description of the Related Art An electric vehicle of this type will be described with reference to the electric wheelchair shown in FIG. The electric wheelchair 1 includes a vehicle body 2 and wheels 3,
4, a motor 5, a control device 6, a battery 7 and the like. The vehicle body 2 is generally composed of a pipe frame, and is provided with a push handle 11 having a grip 10, a backrest 12, a seat 13, an elbow pad 14, a foot plate 15, two drive wheels 3 and two free wheels 4 and the like. Has been.

As the motor 5, a DC motor with a gear is generally used, and one motor is connected to one drive wheel 3 via a gear transmission mechanism. A clutch is attached to the motor 5 or the gear transmission mechanism, and when the clutch is disengaged, the drive wheels 3 become free. Then, the caregiver standing behind the electric wheelchair 1 grips the grip 10 of the push handle 11,
The electric wheelchair 1 can be moved forward or backward.

A joystick lever 16 for control, a power switch, a battery meter and the like are attached to the control device 6. The joystick lever 16
Direction control is performed according to the tilted direction of the lever 16, and the lever 1
The speed is controlled at the tilted angle of 6. Therefore, the tilted angle of the lever 16 is electronically detected, and the rotation speed of the motor 5 is changed accordingly. Further, as the battery 7, a lead acid battery for an automobile is generally used.

[0005]

The electric wheelchair described in the prior art is either electrically propelled or manually disengaged from the clutch of the drive wheel 3. Since a person in a wheelchair can weigh hundreds of tens of kilograms, it can be pushed only on a flat horizontal road, and even if a caregiver is present, it will rely on electric propulsion. Therefore, there is a problem that the battery is heavily consumed and needs to be charged frequently.

The present invention has been made in view of the above problems of the prior art, and its object is to easily detect the operation force of a person such as a caregiver pushing an electric wheelchair. It aims to provide an electric vehicle that can be utilized as a battery to save battery power.

[0007]

An electric vehicle that achieves the above object is an electric vehicle that is driven by a driving force of a motor by rotating wheels so that the vehicle can be moved forward or backward by a person. An operation force detection unit that is rotatably supported by a fixed shaft and that detects an operation force of a person and generates an electric signal according to the operation force is provided on the fixed shaft. A converter for generating a drive signal for the motor based on the above is provided, and a controller for controlling the output of the motor by the drive signal from the converter is provided.

[0008]

When a caregiver or the like applies an operating force to move the vehicle forward or backward to the vehicle, the fixed shaft that supports the wheels on the vehicle body is bent, and the detection unit provided on the fixed shaft sends an electric signal according to the operating force. Based on this electric signal, the converter generates a large driving signal for a large electric signal, and the motor is driven by the driving signal corresponding to the magnitude of the man's operating force. It

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a main part of a drive wheel to which an operation force detection unit is attached, and FIG. 2 is a drive block diagram of an electric vehicle.

In FIG. 1, a fixed shaft 31 of a drive wheel 30
A strain gauge 21 is attached to the. Drive wheel 30
A battery, a signal conversion unit, and a motor control unit are built in the central portion 34, and a tire 36 is provided via a ring-shaped motor 35.
Is driven. Therefore, the central portion 34
Does not rotate and is fixed to the vehicle body 2 by a fixed shaft 31. Since the operating force of a person is transmitted to the wheels 30 via the vehicle body 2 and the fixed shaft 31, the fixed shaft 31 receives a bending load in the thickness direction of the paper surface, and the strain gauge 21 moves forward or backward to operate. A compressive force or a tensile force depending on the direction acts. When the driving force detection unit, the battery, the signal conversion unit, the motor control unit, and the like are built in the drive wheels in this manner, the troublesome parts to be joined with the vehicle body are reduced, which is suitable for mass production and the number of assembly steps is reduced.

In FIG. 2, the electric signal f1 corresponding to the operating force from the operating force detection sensor 21 is input to the signal converting unit 23, the motor converting signal f2 is output from the signal converting unit 23 to the motor control unit 24, and the motor The controller 24 controls the output of the motor 5. The signal conversion unit 23 is an A / D converter 23 that converts the analog electric signal f1 into a digital signal.
a, a CPU (23b) that calculates a signal based on a program stored in advance, and a D / A converter 23c that converts a digital signal into an analog torque drive signal f2.
It consists of

Next, the arithmetic processing of the CPU (23b) will be described with reference to FIG. FIG. 3A is a graph showing the output relationship between the electric signal f1 and the torque drive signal f2 corresponding to the operating force, and FIG. 3B is a graph showing the relationship between the electric signal f1 and the vehicle acceleration. At point C, the operating force is zero,
The drive signal f2 is also zero output, and the acceleration is also zero.
Point B is a dead zone where the operating force is small, and the drive signal f2 remains at zero output, but the acceleration increases by the amount of acceleration due to the operating force of the person. The dead zone is provided to prevent the motor from following a small operating force and destabilizing the vehicle propulsion. Next, at point A, the operating force is large, the drive signal f2 increases proportionally from point a, and the acceleration is the sum of the acceleration due to the human operating force and the acceleration due to the motor. A, B
The points are the case where the person accelerates the vehicle, but the points D and E are the case where the person decelerates the vehicle, and the drive signal f2 and the acceleration are point-symmetrical and are negative. That is, at point A or point E, the acceleration of the vehicle = the acceleration due to the human operating force +
It becomes the acceleration of the motor, and the torque of the motor changes depending on the magnitude of the operating force of the person. Note that FIG. 3 is a graph assuming a horizontal flat road, but when the vehicle goes up and down a slope, the acceleration of the motor also increases according to the magnitude of the operating force of the person against the acceleration of gravity. Only. Further, the joystick lever in FIG. 8 is still in the neutral position, and the occupant is in the state of leaving the operation to the caregiver.

As described above, the motor is not driven independently and complements the human operation, so that the vehicle is propelled in the same sense as human-powered operation. This state will be described with reference to FIG.
FIG. 4A is a graph showing a change in vehicle speed over time, and FIG. 4B is a graph showing a change over time in human operating force. If the operating force is large on the plus side as at point A, the vehicle speed increases rapidly. When the operating force is small on the plus side, as at point B, the vehicle speed gradually increases. When the operating force is zero as at point C, the vehicle speed does not change and only inertial propulsion is performed. When the operating force is small on the minus side as at the point D, the vehicle speed gradually decreases. When the operating force is large on the minus side as at point E, the vehicle speed drops sharply. Note that FIG. 4 shows an ideal case where there is no friction.

In the above-mentioned embodiment, the vehicle is accelerated or decelerated by the manipulating force of the person. However, the direction change operation of the vehicle can be controlled by the signal conversion unit 23 shown in FIG. This direction control will be described with reference to the comparison table of FIG. Reference numerals 1 to 5 are cases where the operating forces applied to the left and right steering wheels are equal, reference numeral 1 corresponds to point C, reference numeral 2 corresponds to point B, reference numeral 3 corresponds to point A, and reference numeral 4 corresponds to point D. The reference numeral 5 corresponds to point E. Reference numerals 6 to 11
Is a case where the left and right operating forces are different, and the motor complements that the vehicle changes direction due to human power. Reference numeral 6 indicates a case where the left operation force is small in the plus direction and the right operation force is large in the plus direction, and each of the left and right motors is interlocked with the left and right operation forces so that the vehicle operates in the left curve. Reference numeral 7 indicates a case where the left operation force is small in the minus direction and the right operation force is large in the plus direction, and the vehicle operates in a sharp left turn. Reference numeral 8 indicates a case where the left operation force is large in the minus direction and the right operation force is large in the plus direction, and the vehicle operates by left rotation. Reference numeral 9 is a case where the reference numeral 6 is opposite to the left and right,
Reference numeral 10 is a case where the reference numeral 7 is opposite to the left and right, and reference numeral 11 is a case where the reference numeral 8 is opposite to the left and right. In this way, when the left and right operating forces and the motors connected to the left and right wheels are interlocked, the operation of the vehicle is complemented by the motors as well as the sense of the human operating force.

[0015]

According to the electric vehicle of the present invention, the operating force of a person is accurately and easily measured by the detecting portion provided on the fixed shaft of the wheel, and the motor is driven according to the operating force to drive the person and the electric vehicle. Since the vehicles are jointly promoted, compared with the case of electric propulsion, human operation power is effectively used and battery power can be saved. Further, since the motor is driven according to the operating force of the person, the operation can be performed with the same feeling as in the case where the clutch is disengaged and the operation is performed only by the human power, and the operation can be performed without discomfort.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of a drive wheel to which an operation force detection unit is attached.

FIG. 2 is a drive block diagram of an electric vehicle.

FIG. 3 is a graph diagram of signal conversion in a signal conversion unit.

FIG. 4 is a graph showing the relationship between operating force and motor speed.

FIG. 5 is a comparison diagram showing a relationship between left and right operating forces and vehicle operation.

FIG. 6 is a perspective view of a conventional electric wheelchair.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric wheelchair 2 Vehicle body 21 Strain gauge (operating force detection part) 23 Signal conversion part 24 Motor control part 30 Drive wheel 31 Fixed shaft f1 Electric signal f2 Torque drive signal

Claims (1)

[Claims] 1. An electric vehicle in which a wheel is rotated by a driving force of a motor and propelled so that a vehicle can be moved forward or backward by a person, the wheel being rotatably supported by a vehicle body via a fixed shaft, The fixed shaft is provided with an operation force detection unit that detects an operation force of a person and generates an electric signal corresponding to the operation force, and a conversion unit that generates a drive signal of the motor based on the electric signal of the operation force detection unit is provided. An electric vehicle, comprising: a control unit that controls the output of the motor according to the drive signal of the conversion unit.