JPH0284002A - Travel controller for electric rolling stock - Google Patents

Abstract

PURPOSE:To prevent slip of driving wheel at start by providing a plugging detecting means in a chopper control circuit and separating a time function circuit from the chopper control circuit upon detection of plugging. CONSTITUTION:Plugging operation carried out under a condition where a switch 4 is turned ON and a chopper control circuit 5 is connected with a time function circuit 2 and a multiplier 12 is detected through a plugging detector 7 which produces a plugging detection signal for switching an analog switch 3. Consequently, control current corresponding to the operating amount of an accelerator lever 1 does not pass through the time function circuit 2 but through the multiplier 12, during plugging operation, and the control current is multiplied by 0.7 in this case then it is fed to the chopper control circuit 5. Consequently, proper plugging brake can be achieved with about 70% control current when compared with conventional plugging operation. By such arrangement, slip of driving wheel can be prevented at start.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a running control device for an electric vehicle used in a road environment with a so-called low coefficient of friction, such as in a refrigerated or frozen warehouse.

(Prior art) In the conventional technology, when an electric vehicle (for example, a battery forklift truck) travels in a place where the friction coefficient of the road surface is low, such as a refrigerated or frozen warehouse, the travel operation device is operated as shown in Fig. 6. When operated to the maximum, the rolling resistance τ, · is very small compared to the rolling resistance τ of the normal road surface, so the electric motor generated torque τ, and the rolling resistance τ, ·
As the difference between the two becomes extremely large, a phenomenon occurs in which the drive wheels slip at the time of startup.To deal with this phenomenon, the following methods (1) and (2) have been used.

(11) The travel control device (e.g. accelerator lever) was operated slowly to keep the drive torque low when starting the drive wheels.

(2) The limit value of the current that controls the drive wheels was set low, and the maximum drive torque was kept low.

(Intelligence to be Solved by the Invention) The above-mentioned conventional techniques (11 and (21) each had the following problems.

In (1), it is extremely troublesome to operate the drive control device slowly every time the electric vehicle is started, and it is common to accidentally operate the drive control device forcefully, causing the drive wheels to slip. This has caused a problem in that working time is wasted when the electric vehicle is a cargo handling vehicle, since this prevents the electric vehicle from starting up.

In (2), it is effective on road surfaces with a low coefficient of friction and can prevent the drive wheels from slipping during startup, but - when driving on a ship road surface, a road surface with a normal coefficient of friction. Since the maximum drive torque is kept low, there is a problem that there is a clear lack of torque for acceleration at startup and the acceleration characteristics deteriorate.

(Means for Solving the Problems) Electric vehicle running control device of the present invention (hereinafter referred to as the present invention)
In the above! ! ! ! In order to solve this problem, a means is provided between the travel operation device and the chopper control circuit to count the time since the start of the travel operation device, and a control current value is set based on the operation amount of the travel operation device as time passes. A time function circuit including a time function F (means for multiplying by 0) that changes accordingly is provided, and the chopper control circuit and the time function circuit are connected to each other by a manual switch, and
The configuration includes a multiplication circuit that multiplies an arbitrary multiplication value by operating the manual switch, and further includes means for detecting plugging in the chopper control circuit, and means for separating the time function circuit from the chopper control circuit when plugging is detected. The configuration was as follows.

(Function) To explain the present invention in detail, first, when the changeover switch is turned ON, the analog switch 32 is turned ON and Sl is turned OFF.
It is configured to be an FF, that is, the time function circuit is connected to the chopper control circuit via the multiplication circuit.

When the travel control device is operated to move forward or backward in order to start the electric vehicle in this state, the control current value is determined based on the amount of operation, and the control current value is a time function that changes with the passage of time. After being multiplied by F (t), it is multiplied by a multiplication value by a multiplication circuit. This multiplier circuit operates in conjunction with the operation of the changeover switch, and
The setting is such that a multiplication value of 0.7 is selected with N, and a multiplication value of 1.0 is selected with the changeover switch OFF to be multiplied by the control current value. The control flow value multiplied by an arbitrary multiplier passes through a chopper control circuit to control the electric motor that drives the drive wheels. Furthermore, when driving on a road surface where the coefficient of friction is a normal value, i.e., a normal road surface, the time function circuit and the chopper control circuit are separated by turning off the changeover switch. The activated multiplier circuit selects a multiplier value of 1.0 and multiplies the control current value. The control current value multiplied by the multiplication value of 1.0 flows to the tip/tsuba control circuit and enables normal start-up acceleration running.

Furthermore, when the chopper control circuit and the time function circuit are connected with the changeover switch in the ON state, the braking effect can be increased by plugging operation (instantly operating the travel control device from forward to reverse or from reverse to forward). ), the means for detecting plugging provided in the chopper control circuit detects the plugging operation, and a signal is output to the means for separating the time function circuit and the chopper control circuit. The function circuit and the chopper control circuit are separated, and the control current value based on the operation amount of the traveling operation device is sent to the chopper control circuit through the multiplication circuit without passing through the time function circuit.

(Example) Next, an example of the present invention will be described below with reference to the drawings. 1st
The figure shows a chopper control circuit 5 that controls the rotation of an electric motor 11 mounted on an electric vehicle based on the operation amount of an accelerator lever 1 as a traveling operation device, a time function circuit 2 according to the present invention, an analog switch 3, a changeover switch 4, 1 shows an electrical block circuit diagram of a control circuit with a plugging detector 7 and a multiplication circuit 12; FIG.

A control current value based on the operation amount of the accelerator lever 1 controls the rotation of the electric vait via a time function circuit 2, an analog switch 3, a multiplication circuit 12, and a chopper control circuit 5.

Here, the chopper control circuit 5 is composed of a comparison amplifier 9, a duty command circuit 8, a chopper circuit 6, a plugging detector 7, and a current detector 10.
The control current value based on the operating amount of the accelerator lever 1 is compared with the current value of the motor 11 detected by the current detector 10, and the result is output to the duty command circuit 8, and the chopper duty is determined by the output of the comparator amplifier 9. is determined.

The time function circuit 2 is connected between the accelerator lever 1 and the chopper control circuit 5 via an analog switch 3 and a multiplier circuit 12, and the analog switch 3 switches St to ON1 when the changeover switch 4 is turned on. Switch 4 OF
It is configured such that St is turned ON by F operation. In other words, when the changeover switch 4 is turned OFF, the time function circuit 2 and the multiplier circuit 12 are separated, and the control current value based on the operation amount of the accelerator lever is passed through the multiplier circuit 12 without passing through the time function circuit 2, and then sent to the chopper. The signal flows to the control circuit 5. Here, the multiplier circuit 12 turns on the changeover switch 4,
Operates in conjunction with the OFF operation, and selector switch 4 is OFF
If it is ON, select the multiplication value 1.0, and if it is ON, select the multiplication value 0.
7 is selected and multiplied by the control current value.

Further, the time function circuit 2 includes a timer (not shown) that counts the time from the start operation of the accelerator lever I, and a time function F (t) to the control current value based on the operation amount of the accelerator lever I. It consists of a multiplication circuit as shown in Figure 2.
3 and 4 show that when the changeover switch 4 is in the ON state, that is, the multiplication value of the multiplier circuit 12 is 0.7, the control current value when the accelerator lever 1 is operated to the maximum is determined by the time function F(1). It is a graph showing the relationship between the current value and time controlled by multiplying by . The broken line represents the conventional control current value, that is, in FIGS. 2 and 4, when starting the accelerator lever 1, the current value starts from about 40% of the conventional control current value, and the control current increases for t seconds. The value is multiplied by a time function F (t) so as to show a smooth rise, and the current value after 2 seconds is kept constant at about 70% of the conventional control current value by the multiplication value 0.7 of the multiplier circuit 12. ing. Further, FIG. 3 shows an example in which a time function F (t) that changes stepwise is multiplied by seconds after the accelerator lever 1 is activated.

The time function F (t) here is determined for each elapsed time, and is a function that determines the current value to be passed to the chopper control circuit 5 (for example, there are negative functions, square functions, etc., and it can be freely set depending on the object to be controlled. ), and the range of the time function F (t) used in the present invention is O<F (t)<1.

If a plugging operation is performed when the chopper control circuit 5 is connected to the time function circuit 2 and the multiplier circuit 12 with the changeover switch 4 in the ON state (when the multiplication value of the multiplier circuit 12 is 0.7), plugging is detected. The device 7 detects this and outputs a plugging detection signal, and upon receiving this signal, the analog switch 3 turns off S2 and connects S1. Due to this series of operations, during the plugging operation, the control current value based on the operation amount of the accelerator lever 1 passes through the multiplication circuit 12 without passing through the time function circuit 2, and the multiplication value in this case is 0°7.
The signal is multiplied only by the signal and sent to the chopper control circuit 5.

Therefore, appropriate plugging braking can be obtained with a control current value that is about 70% of that of normal plugging braking.

(Effects) As detailed above, according to the present invention, the electric motor is controlled based on the amount of operation of the travel control device at the time of starting the electric vehicle. I
Since the I current value can be started from a low value of about 40% of the conventional value (at the maximum operation amount of the travel control device) and then smoothly increased to a constant value of about 70% of the conventional value, as shown in Figure 5. As shown in Figure 2, it is possible to smoothly increase the drive torque when starting the electric motor, and the starting torque when starting the electric car can be suppressed, so even when starting the electric car on a road surface with a low coefficient of friction. It is possible to reliably prevent slips, and when driving on a normal road surface, the time function circuit can be separated from the chopper control circuit by a manual switch, so it can go back and forth between a road surface with a low coefficient of friction and a normal road surface. Even in the event of a road failure, it is possible to instantaneously perform driving control of the electric motor that corresponds to both road surfaces.

Furthermore, during plugging operation, the time function circuit is separated from the chopper control circuit using an analog switch, and the multiplication value of the multiplier circuit is used to control the control current value required for plugging braking. Provides braking force that prevents slippage. Therefore, even during plugging braking, a reliable braking effect without slipping is achieved. Figure 5 is a graph showing the relationship between the torque and time at the time of starting the electric motor according to the present invention, and Figure 6 is a graph showing the relationship between the torque and time at the time of starting the electric motor according to the present invention. It is a graph showing the relationship with time.

■・・・・・・Accelerator lever 2・−・−・・Time function circuit 3---Analog switch 4-・・・Selector switch 5--Chopper control circuit 6...--Chopper circuit 7...--Plugging detection circuit 8-...-...Duty command circuit 9...Comparison amplifier 10---- Current detector 11・---・Electric motor

Claims (1)

[Scope of Claims] 1. An electric vehicle in which a drive wheel is driven by an electric motor via a chopper control circuit, and the chopper control circuit is configured to output current or voltage based on the operating amount of a travel operating device. , a means for counting time from activation of the traveling operation device is provided between the traveling operation device and the chopper control circuit, and a means for counting the time from the activation of the traveling operation device, and a means for changing the control current value based on the operation amount of the traveling operation device as time passes. The changing time function F(
1. A running control device for an electric vehicle, characterized in that a time function circuit is provided with means for multiplying by t). 2. The electric power supply according to claim 1, wherein the chopper control circuit and the time function circuit are connected in a separable manner by a manual switch, and further includes a multiplication circuit that multiplies an arbitrary multiplication value by operating the manual switch. Car travel control device. 3. The running control device for an electric vehicle according to claim 2, wherein the chopper control circuit is provided with means for detecting plugging, and means for separating the time function circuit from the chopper control circuit when plugging is detected.