JPH01174203A - Accelerator controller for electric motor car - Google Patents

Abstract

PURPOSE:To level of control in the whole operation range of an accelerator, by setting a characteristic changing means for changing the changing degree of input signal. CONSTITUTION:The accelerator voltage VACC1 of output generated from a variable resistor 30 jointed to an accelerator is fed to an absolute value amplifier 36 via an integrator circuit composed of a resistor 32 and a capacitor 34. By a comparator 46, the output voltage VACC2 of the absolute value amplifier 36 and a chopping wave from a chopping wave generator 48 are compared with each other, and the output of PWM controlling signal is directed to a driver 50. In the meantime, by a characteristic changing means composed of a resistor 38 and a Zener diode 40, the output voltage VACC2 of the absolute value amplifier 36 is limited to a specified value. As a result, operating property is improved, and control can be levelled off.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an accelerator control device for an electric vehicle, such as an accelerator control device suitable for controlling or operating an electric wheelchair. It is related to.

(Prior Art) In an electric vehicle, for example, an electric wheelchair, the control or operation is usually performed by tilting the accelerator or the lever of the control terminal.In other words, the resistance value of the variable resistor is adjusted in conjunction with the operation of the accelerator. By changing
The accelerator operation amount is converted into an electrical signal to obtain an accelerator voltage, and drive control is performed based on this.

The relationship between the accelerator voltage V Ace and the lever operation angle (hereinafter referred to as "lever angle") θ is shown in FIG. 2 (A).
There is often a proportional relationship as shown in .

In addition, when the lever angle θ is small, the accelerator voltage v, C
does not come out, but this is due to the play in the lever.

The relationship between the accelerator voltage v ace and the motor rotation speed when traveling on a flat road in the above case is shown in the same figure (
The relationship is non-linear as shown in B). That is, when the accelerator operation amount (accelerator voltage Vacc) is small,
The change in motor rotation speed is also small, but as the amount of accelerator operation increases, the change in motor rotation speed also increases.

Therefore, fluctuations in the motor rotation in the fully open range become large, which causes fluctuations when traveling straight ahead.

In order to prevent such inconveniences, it is necessary to make the slope ■Acc/θ nonlinear, which is opposite to that shown in FIG. 13(B), as shown in FIG.

There are ways to improve these points by making the characteristics of the variable resistor itself special, or by mechanically changing the relationship between the movement of the lever and the change in the resistance value of the variable resistor. .

[Problem that the invention seeks to solve]

However, the former method is disadvantageous in that it is difficult to manufacture the variable resistor and the variation between elements becomes large.

In addition, in the latter mechanically applicable method, if you try to cut and try to obtain the desired characteristics, you will have to make various structural changes to change the characteristics, and it is not always easy to obtain the desired characteristics. The disadvantage is that it is not possible.

[Purpose of the invention]

The object of the present invention has been made in view of the above points, and is to provide an electric vehicle in which the amount of operation of the accelerator corresponds well to changes in vehicle speed over the entire operation range of the accelerator, and the control can be flattened. An object of the present invention is to provide an accelerator control device.

[Means for solving problems]

The present invention provides an accelerator control device for an electric vehicle that converts an accelerator operation amount into an accelerator signal of a corresponding electrical amount using a variable resistor, and controls the drive of a motor based on the accelerator signal. A characteristic changing means for changing the amount of change and outputting the output; and applying an accelerator signal obtained by a variable resistor at a positive potential to the anode of the Zener diode, and having a current margin that is approximately the Zener voltage of the Zener diode. The configuration includes an input impedance amplifying means of approximately This is intended to achieve the objectives mentioned above.

[For production]

According to this invention, the amplification means applies an accelerator signal having a positive potential Zener voltage or so and having a current margin to the anode of the Zener diode of the characteristic changing means.

The input accelerator signal is outputted from the characteristic changing means with the amount of change or slope changed.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

First, the basic configuration of this embodiment will be explained based on FIG. Note that the device shown in the figure is provided for each of the left and right drive motors.

In FIG. 1, an accelerator 10, which is a lever for driving the electric vehicle, is connected to a converting means 12 constituted by a variable resistor.
, so that the mechanical operation amount of the accelerator 10 is converted into an electrical amount, the accelerator voltage (1, 1), and output.

The accelerator voltage VACCI is amplified by the amplifying means 14 and then input to the characteristic changing means 16.

As will be described later, this characteristic changing means 16 is composed of a resistor and a Zener diode, and has a function of outputting a voltage having a predetermined relationship with the input voltage. That is, when the accelerator voltage v accz as shown by the broken line LA in FIG. 3 is input from the amplification means 14, it has a function of changing the voltage and outputting it as shown by the actual LB in the same figure.

Next, the voltage-changed signal is input to the PWM means 18. A triangular wave generating means 20 is connected to this PWM means 18, and PWM (pulse width modulation) is performed using the inputted triangular wave, and a modulated signal is inputted to the driving means 22. .

The drive means 22 is configured to supply driving power to the motor 24 based on input.

Next, the operation of the embodiment configured as above will be explained.

When the user of the electric vehicle operates the accelerator 10, the accelerator voltage VA is output from the conversion means 12 depending on the degree of lever movement.
The CCI is output and is amplified by the amplifying means 14.

The relationship between this amplified accelerator voltage VACCI and the lever angle θ is as shown by the broken line LA in FIG.

Next, the characteristic changing means 16 changes the characteristics of the accelerator voltage v hcct, and the changed voltage V ACCI shown by the solid line LB in the figure is input to the PWM means 18.

The PWM means 18 performs PWM using the changed voltage V Al:C2 and a triangular wave, and a modulation signal is input to the drive means 22, which then drives the motor 24.

Next, an example will be described with reference to FIG. In the figure, the variable resistor connected to the above-mentioned accelerator 10 has an operating voltage ■. , and ground, and the output side of the accelerator voltage VACCI is connected to a resistor 32. It is connected to the input side of an absolute value amplifier 36 via an integrating circuit constituted by a capacitor 34.

The neutral point of the variable resistor 30 mentioned above is Vcc/2, and this voltage corresponds to the stopped state of the electric vehicle. That is, when a voltage higher than this is output, it indicates forward movement, and when a voltage lower than this is output, it indicates backward movement.

Further, VCC/2 is also input to the absolute value amplifier 36, and the input signal is amplified using this as a reference.

Next, a series circuit of a resistor 38 and a Zener diode 40 is connected to the output side of the absolute value amplifier 36 and connected to the ground.
2, and this series circuit includes a resistor 44.
are connected in parallel.

Further, the output side of the absolute value amplifier 36 is connected to the positive input side of a PWM comparator 46 via a resistor 42. A triangular wave from a triangular wave generator 48 is input to the negative input side of the comparator 46 . Further, the output side of the comparator 46 is connected to the drive device 50.

Among the above parts, the absolute value amplifier 36 is shown in FIG. 5(A).
For the accelerator voltage VACCI which changes around VCC/2 as shown in FIG.

Next, the above-mentioned resistor 38 and Zener diode 40 constitute the characteristic changing means 16 shown in FIG.

The Zener diode 40 has characteristics as shown in FIG. 6, and the reverse current (Zener current) increases rapidly at a predetermined reverse voltage (2). Therefore, even if a voltage higher than the Zener voltage 12 is applied, the voltage between the terminals close to the Zener voltage 2 is maintained as long as the Zener current 2 is allowed. It is one of the so-called nonlinear elements.

The relationship between the input accelerator voltage V accz of the series circuit of the resistor 3 and the Zener diode 40 and the output side change voltage V ACC3 is as shown by the broken line in FIG. At this time, by appropriately selecting the value of the resistor 38, the characteristics can be freely changed as shown in LC and LD in the figure.

Note that LE in the figure shows the case where the series circuit of the resistor 38 and the Zener diode 40 is not connected.

Such gentle characteristics are obtained by effectively using the area where the Zener current (2) is small, which corresponds to the shaded area in FIG.

Next, the operation of the above embodiment will be explained. variable resistance 3
The accelerator voltage VACC+ output from 0 is amplified in the absolute value amplification 36 as shown in FIG. 5, and the accelerator voltage VACC2 is output. The relationship between the accelerator voltage VACCI and the lever angle θ is a proportional relationship as shown in FIG. 2(A).

Next, when this accelerator voltage V ACC2 is input to a parallel circuit of a 38° Zener diode 40, an output change voltage V ACC3 is outputted with the relationship shown in FIG.

For this reason, the change voltage ■. , 3 and the lever angle θ is as shown in FIG. 2(C). This change voltage V
PWM is performed by the comparator 46 based on ACC:1, and the motor is driven by the drive device 50 based on the modulation signal.

Therefore, the accelerator voltage VACCI (or Vcc
z) and the motor rotation speed as shown in Fig. 2 (B), the characteristics will be changed favorably, especially the motor rotation fluctuations in the fully open range will be suppressed, and the motor rotation speed will be reduced when driving straight ahead. This will effectively prevent unevenness and the like.

As described above, according to this embodiment, the accelerator signal is
A positive potential is applied to the anode of the Zener diode through an absolute value amplifier, and the input impedance to the absolute value amplifier is made low enough to obtain the Zener voltage, so as to have a current margin. Therefore, the characteristics of the variable resistor 30 can be corrected isometrically and satisfactorily.

Therefore, it is possible to use a variable resistor with a B-curve characteristic that is the cheapest and has the least variation, and it is also possible to use a high-grade potentiometer made of conductive plastic or the like, which has a B-curve characteristic in most cases.

Note that the present invention is not limited to the above-mentioned embodiments (it is possible to change the design of various devices so as to perform similar functions).

For example, in the above embodiment, various characteristics were obtained by appropriately setting the value of the resistor 38, but the Zener diode 40
Characteristics can be changed in the same way by changing the Zener voltage (2). However, in order to improve the Zener effect, that is, to increase the flatness of the curve near ±Omax (see Figure 3), it is necessary to decrease the value of the resistor 42 and increase the Zener current I2. However, this is not preferable because the rise in the intermediate range becomes abrupt.

〔Effect of the invention〕

As explained above, according to the present invention, the vehicle speed follows the lever angle better not only in the fully open range but also in the intermediate range, improving operability and flattening the control. It is possible to provide an excellent electric vehicle drive control device that is not available anywhere else.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between accelerator voltage, lever angle, and motor rotation speed, and FIG. 3 is a diagram showing the action of the characteristic changing means. Figure 4 is a circuit diagram showing the circuit configuration of the embodiment, Figure 5 is a diagram showing the action of the absolute value amplifier, Figure 6 is a diagram showing an example of the characteristics of a Zener diode, and Figure 7 is a diagram showing the characteristic change. FIG. 3 is a diagram showing the relationship between input and output of means. 10... accelerator, 12... changing means, 14...
Amplifying means, 16... Characteristic changing means, 18... PWM
Means, 22... Drive means, 24... Motor, 3
0...Variable resistor, 38...Resistor, 40...Zena diode. Patent applicant Suzuki Motor Co., Ltd. Figure 2 □ C (1).

Claims (1)

[Claims] (1) An accelerator control device for an electric vehicle that changes the amount of accelerator operation by a variable resistor into an accelerator signal of an opposing electrical amount, and controls the drive of a motor based on this, which includes a Zener diode and converts the input signal into an accelerator signal. a characteristic changing means for changing the amount of change and outputting the output; and applying the accelerator signal at a positive potential to the anode of the Zener diode, and having an input impedance that is about the Zener voltage of the Zener diode and has a current margin. An accelerator control device for an electric vehicle, characterized by comprising an amplifying means.