JPH01170301A - Travel controller for motor driven vehicle - Google Patents

Abstract

PURPOSE:To obtain a suitable braking force at the time of controlling plugging by outputting a command having a predetermined conduction rate when the command of a conduction instruction unit decreases lower than the predetermined conduction ratio, and reducing an acceleration command when the conduction ratio command decreases lower than a predetermined value. CONSTITUTION:A conduction ratio instruction unit 5 compares an acceleration command signal from an acceleration instruction unit 3 with a motor current from a motor current detector 7, and it outputs a conduction ratio command. A command selector 17 selects a larger one of a conduction ratio command and a predetermined conduction ratio from a predetermined conduction ratio instruction unit 13, and outputs it to a chopper 9. On the other hand, a conduction ratio comparator 21 reduces the signal from the unit 3 when the output of the selector 17 decreases lower than a predetermined value. Thus, the vibration of an automotive body can be suppressed at the time of controlling plugging.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) This invention relates to an electric vehicle travel control device for a battery-powered forklift or the like.

(Prior Art) As a conventional electric vehicle travel control device, there is, for example, the one shown in the block diagram of FIG. 3.

A command corresponding to the depression of the accelerator 101 is issued from the accelerator command section 103 to the conduction rate command section 105. Then, the conduction rate is determined by the accelerator command from the accelerator command unit 103 and the feedback current from the motor current detection unit 107, and the conduction rate command is issued to the chopper 109. If this current flow rate is small, the motor 1 for driving an electric vehicle
The average voltage applied to 11 is also small, and the electric vehicle runs at low speed. Furthermore, when the flow rate increases, the vehicle will run at high speed.

On the other hand, braking force can be applied to the vehicle body by plugging control while such an electric vehicle is running.

That is, when the driver depresses the accelerator 101 while driving and switches from forward (or reverse) to reverse (or forward), the motor 111 acts as a generator and applies braking force to the vehicle body.

(Problem to be Solved by the Invention) By the way, during such arranging control, a large current temporarily flows through the motor 111 as shown in FIG. , ``Due to the conduction rate control of the feedback system shown in Figure 3, the conduction rate becomes low (about 1 to 3%) as shown in Figure 4(a), and the control system becomes unstable.Moreover, the plugging control Sometimes, a large torque is generated on the axle shaft at the start of the process, and the backlash of the gears causes vibrations in the drive system, causing uneven rotation of the motor.

As a result, the motor current fluctuates and the control system becomes unstable, and the feedback control system also vibrates, which may increase vehicle body vibration (shudder), especially when driving at low speeds.

On the other hand, when the conduction rate fluctuates due to the shooting of the feedback control system as described above during plugging control, instead of this, it is possible to output a constant conductivity rate that is slightly higher regardless of the accelerator command. The flow rate is stabilized, and the above-mentioned vehicle body vibrations can be suppressed. However, if a constant conductivity rate that is slightly higher than the fluctuating conductivity rate is simply produced as described above, the braking force will become slightly higher, and there is a risk that the braking shock will become larger.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electric vehicle control device that can obtain an appropriate braking force during plugging control and can suppress vehicle body vibration.

[Structure of the invention] (Means for solving the problem) In order to solve the above problem, the present invention uses feedback of the accelerator command and the motor current to issue a conduction rate command in a conduction rate command section and apply it to the motor. In an electric vehicle running control device that controls voltage conduction rate, when a command from the conduction rate command section is lower than a predetermined conduction rate, a constant conduction rate is provided that issues a command at a constant conduction rate that is greater than the predetermined conduction rate. a command unit; and a command lowering unit that lowers the accelerator command when the conduction rate from the conduction rate command unit is below a certain value, and causes the command of the conduction rate command unit to go below a predetermined flow rate. The configuration is such that

(Function) Even if the command from the conduction rate command section fluctuates below a predetermined conduction rate during plugging control, the conduction rate command section outputs a constant conduction rate, so stable control can be achieved. Moreover, when the conduction rate from the conduction rate command section is below a certain value, the command reduction section lowers the accelerator command to make the command from the conduction rate command section lower than the predetermined conduction rate. can be made appropriate without becoming too high, and an increase in braking force is suppressed.

(Example) This invention will be explained in detail below.

FIG. 1 shows an electric vehicle traveling control Il according to an embodiment of the present invention.
FIG. 2 is a block diagram of the device.

This electric vehicle control device also includes an accelerator command section 3 that issues an accelerator command using the accelerator 1, a conduction rate command section 5, a motor current detection section 7, a chopper 9, and a vehicle running motor 11.

On the other hand, one embodiment of the present invention further includes a -current rate command section 13 and a command lowering section 15.

The conduction rate command section 13 outputs the conduction rate when the command from the conduction rate command section 5 is lower than a predetermined conduction rate, and the command selection section 17 and the conduction rate command section 19 It consists of This current flow rate corresponds to an appropriate average voltage applied to the motor 11 in order to obtain an appropriate braking force during plugging control, for example.

The command reduction section 15 reduces the accelerator command from the accelerator command section 3 when the conduction rate from the conduction rate command section 5 falls below a certain value. Therefore, a signal from the conduction rate comparison section 21 is input to the command reduction section 15, and the conduction rate comparison section 21 detects the conduction rate input to the chopper 9. A signal from the conductivity detection section 23 is input. The conductivity comparison section 21 determines whether the detected conductivity is below a certain value. This constant value is slightly larger than the fluctuation range of the conduction rate during the plugging control shown in FIG. There is.

Next, the operation of the above embodiment will be described. First, during normal running control, the accelerator command unit 3 issues an accelerator command to the conduction rate command unit 5 in response to the depression of the accelerator 1.

The conduction rate command unit 5 outputs an accelerator command and a motor I! Detection section 7
The conduction rate is determined based on the feedback from the current conduction rate command section 13, and is input to the command selection section 17 of the conduction rate command section 13. When the conduction rate commanded from the conduction rate command section 5 exceeds a predetermined conduction rate, for example, when it exceeds the conduction rate from the conduction rate command section 19, the conduction rate of the conduction rate command section 5 is selected. be done. During normal running control, the conduction rate command from the conduction rate command unit 5 sets a predetermined conductivity rate on the road, so the conductivity rate of the conduction rate command unit 5 is inputted to the chopper 9 as is. When the conduction rate is low, the average voltage applied to the motor 11 is low and the vehicle runs at low speed. Furthermore, when the conduction rate increases, high-speed running is performed.

When plugging control is performed in such normal running control, a large current flows through the motor 11, so the conduction rate command unit 5
The conductivity determined by is low and variable. Here, if an attempt is made to stabilize the control with a constant conduction rate (constant value) that slightly exceeds this variation, the braking force will increase.

Therefore, the output from the conduction rate command section 5 is the output from the conduction rate detection section 23.
and is input to the conductivity comparison section 21. The conductivity comparison unit 21 determines whether the input conductivity is less than the certain value. During plugging control, it is determined that there is a conflict in which the conduction rate is below a certain value, and the command reduction unit 15 reduces the accelerator command from the accelerator command unit 3. Therefore, the output from the conduction rate command section 5 is lower than the predetermined conduction rate, the output from the command selection section 17 is selected as the constant conduction rate from the conduction rate command section 19, and the constant value is sent to the chopper 9. A constant conduction rate lower than 100% will be input.

Therefore, even during plugging control, the conduction rate can be stabilized at, for example, 4 to 5%, and even if vibration occurs in the drive system due to large torque generation and gear backlash during plugging control, the control system can be stabilized. It is possible to stabilize the vehicle and prevent the vehicle from being photographed.

Furthermore, as mentioned above, during plugging control, a constant conduction rate is output from the conduction rate command section 19, but since the accelerator command is decreased in the command reduction section 15, the conduction rate of the feedback system varies. By reducing the width, an appropriate constant flow rate that slightly exceeds this swing width can be input to the chopper 9, and an appropriate braking force can be obtained.

FIG. 2 shows another embodiment of the present invention, which includes a start detection section 25 for detecting that the accelerator 1 is turned on and an interface for canceling the operation of the command lowering section 15 compared to the embodiment shown in FIG. A lock portion 27 is added.

That is, in the above-mentioned traveling control 11 device, the flow rate is low even when starting as shown in FIG. This will cause a decline in the quality of the product. Therefore, when the vehicle is accelerated to a certain extent and the flow rate increases, the command lowering section 15 no longer lowers the accelerator command, and the accelerator command from the accelerator command section 3 suddenly increases, causing gradual acceleration when the vehicle starts. This results in a poor starting feeling.

However, according to the embodiment shown in FIG. 2, when the accelerator is turned from off to on at the time of starting, the start detection section 25 detects this, and the interlock section 27 stops the operation of the command lowering section 15 for a predetermined period of time.

Therefore, the stepwise acceleration when starting the vehicle as described above is prevented, and deterioration of the starting feeling can be prevented. In addition, since the accelerator 1 remains on during plugging, there is no detection by the oscillation detector 25, and the command lowering unit 15
will work normally. [Effects of the Invention] As is clear from the above, according to the configuration of the present invention, when the commanded conduction rate of the conduction rate command section is lower than the predetermined conduction rate, - the constant conduction rate is set from the current conduction rate command section. Since the command is issued, the control system is stabilized, and vehicle body photography during plugging control can be suppressed. Also, during plugging control,
Since the command reduction section lowers the accelerator command and reduces the amplitude of fluctuation in the conduction rate of the feedback system, the braking force during plugging control can be maintained at an appropriate strength without increasing the constant conduction rate.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an electric vehicle control device according to an embodiment of the present invention, Fig. 2 is a block diagram of an embodiment of the same, Fig. 3 is a block diagram of a conventional example, and Fig. 4 is a waveform diagram. It is. 1...Accelerator 3...Accelerator command section 5...Action rate command section 11...Motor 13.
...-running flow rate command section 15...command lowering section agent
Patent Attorney Yasuo Miyoshi’s Figure 4 (a) Figure 4 (b)

Claims (1)

[Claims] In an electric vehicle running control device in which a conduction rate is commanded by a conduction rate command section based on an accelerator command and motor current feedback, and a conduction rate is controlled by a voltage applied to a motor, the command from the conduction rate command section is set to a predetermined rate. a constant conductivity command section that issues a command at a constant conductivity rate greater than the predetermined flow rate when the flow rate is below the predetermined flow rate; and a constant conductivity command section that issues the accelerator command when the conductivity rate from the conductivity rate command section is below a certain value. An electric vehicle running control device comprising: a command lowering section for lowering a value.