JPH089508A - Travel controller for battery-driven vehicle - Google Patents

Abstract

PURPOSE:To keep a vehicle smoothly traveling at the time of switching between different operation modes of a drive motor. CONSTITUTION:Output signals from a rotation sensor 4, an acceleration sensor 5a and a forward/reverse switch 6a are sent to a control circuit 7, which decides any of a plurality of drive modes previously set based on the signals, and controls a power converter 2 in response to the decided mode, thereby driving a traveling motor 3. Further, when the circuit 7 decides the switching of the mode, it so controls the converter 2 that the output torque of the motor 3 is not abruptly changed in response to the combination of the mode before and after the switching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a travel control device for a battery type vehicle such as a battery type forklift.

[0002]

2. Description of the Related Art In a battery-powered vehicle such as a battery-powered forklift, the vehicle is powered by rotating a traveling motor in accordance with the amount of depression of an accelerator pedal. It That is, by setting the forward / reverse lever to forward or reverse and depressing the accelerator pedal, the traveling motor rotates in the normal or reverse direction, and the vehicle moves in the forward or reverse direction.
As the braking during traveling, regenerative braking by accelerator-off regenerative operation for turning off the accelerator or switchback regenerative operation for switching the forward / reverse lever in the opposite direction is generally adopted.

As described above, the operating mode of the traveling motor can be switched among the power running mode, the accelerator-off regenerative mode and the switchback regenerative mode in response to changes in the operating condition of the vehicle. Since the direction or magnitude of the torque generated in the motor drastically changes, the movement of the vehicle is awkward and not smooth.

[0004]

As described above, the conventional battery-powered vehicle has a problem that the movement of the vehicle is not smooth when the driving motor is switched to the operation mode. The present invention has been made in order to solve such a conventional problem, and provides a travel control device for a battery-powered vehicle capable of switching the operation mode of a travel motor while smoothly traveling the vehicle. With the goal.

[0005]

In order to achieve the above-mentioned object, a traveling control device for a battery type vehicle according to the present invention uses a traveling motor for rotating a drive wheel of the vehicle in a normal direction or a reverse direction and electric energy from a battery. A drive circuit that drives the travel motor, a rotation sensor that detects the rotation speed and rotation direction of the travel motor, an accelerator sensor that detects the amount of depression of the accelerator pedal, and a front and rear for setting the forward or reverse traveling direction of the vehicle. A forward lever, a forward / backward switch that detects the traveling direction set by the forward / backward lever, and a plurality of operating modes preset based on the output signals from the rotation sensor, the accelerator sensor, and the forward / backward switch. It is provided with a control circuit that determines which operation mode is in operation and controls the drive circuit according to the operation mode. When the control circuit determines the switching of the operation mode, the control circuit controls the drive circuit such that the change in the output torque of the traveling motor is moderated according to the combination of the operation modes before and after the switching.

[0006]

In the traveling control device having the above structure, the rotation sensor detects the rotation speed and the rotation direction of the traveling motor, the accelerator sensor detects the depression amount of the accelerator pedal, and the forward / reverse switch is set by the forward / reverse lever. Detects the traveling direction of the vehicle. The control circuit determines, based on the output signals from the rotation sensor, the accelerator sensor, and the forward / reverse switch, which one of a plurality of preset operating modes is the operating mode, and the determined operating mode. The drive circuit is controlled according to the above to drive and control the traveling motor. Further, when the control circuit determines that the operation mode has been switched, the control circuit controls the drive circuit so that the output torque of the traveling motor does not suddenly change according to the combination of the operation modes before and after the switching.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows the configuration of a travel control device for a battery-powered vehicle according to an embodiment of the present invention. An electric power converter 2 serving as a drive circuit of the present invention is provided to a traveling motor 3 including an induction motor for rotating drive wheels of a vehicle (not shown).
Is connected, and the battery 1 mounted on the vehicle is connected to the power converter 2. A rotation sensor 4 for detecting the number of rotations and the rotation direction of the traveling motor 3 is connected to the traveling motor 3. Further, the vehicle is provided with an accelerator pedal 5 and a forward / backward movement lever 6, an accelerator sensor 5a for detecting the amount of depression thereof is connected to the accelerator pedal 5, and the forward / backward movement lever 6 is set by the forward / backward movement lever 6. A forward / reverse switch 6a for detecting the traveled direction is connected. Further, a control circuit 7 is connected to the rotation sensor 4, the accelerator sensor 5a, and the forward / reverse switch 6a, and the output of the control circuit 7 is connected to the power converter 2. The control circuit 7 can be composed of an appropriate microcomputer.

Next, the operation of this embodiment will be described. The control circuit 7 calculates the speed of the vehicle based on the number of revolutions of the traveling motor 3 detected by the rotation sensor 4, while the rotation direction (forward / reverse direction) of the traveling motor 3 detected by the rotation sensor 4, The operation mode is determined based on the depression state (ON / OFF) of the accelerator pedal 5 detected by the accelerator sensor 5a and the set traveling direction (forward / reverse) detected by the forward / reverse switch 6a.

That is, as shown in FIG. 2, when the accelerator pedal 5 is in the ON state (stepped on), the forward / backward lever 6 is set in the forward direction and the traveling motor 3 is rotating in the forward direction. When the power running mode A in the forward direction and the forward / backward lever 6 are set in the reverse direction and the traveling motor 3 is rotating in the reverse direction, the power running mode B in the reverse direction is determined. Similarly, when the accelerator pedal 5 is on,
The forward / reverse lever 6 is set in the backward direction and the traveling motor 3
Is in the forward direction, the forward-back switchback regeneration mode E is set. When the forward / reverse lever 6 is set in the forward direction and the traveling motor 3 is rotating in the reverse direction, the backward-direction switchback regeneration mode F is set. Each is determined. Also,
When the accelerator pedal 5 is in the off state (not depressed), if the traveling motor 3 is rotating in the forward direction, the accelerator-off regeneration mode C is in the forward direction, and if the traveling motor 3 is rotating in the reverse direction. It is determined to be the accelerator-off regenerative mode D in the reverse direction.

In accordance with the operation mode thus determined, the control circuit 7 determines, based on the rotational speed of the traveling motor 3 detected by the rotation sensor 4 and the depression amount of the accelerator pedal 5 detected by the accelerator sensor 5a, The traveling motor 3 is drive-controlled by switching the some power element which comprises the electric power converter 2. The method for controlling the drive of the traveling motor 3 in each operation mode is not particularly limited, but, for example, Japanese Patent Application No.
-230414 is described in the specification, and this is shown in the rotation speed / torque characteristic diagram of FIG. In FIG. 3, the horizontal axis represents the rotational speed of the traveling motor 3, and the vertical axis represents the traveling motor 3.
The respective output torques are shown, and characteristic curves representing the respective operation modes A to F are shown.

For example, the control process by the control circuit 7 when it is determined that the operation mode is the forward power running mode A is shown in the flowchart of FIG. First, step S
At 1, the output signals from the rotation sensor 4, the accelerator sensor 5a, and the forward / reverse switch 6a are input, respectively, and it is confirmed from these signals that the current mode is the powering mode A. Next, in step S2, the immediately preceding operation mode is A
It is determined whether or not Here, when the accelerator pedal 5 is depressed and the set traveling direction by the forward / reverse lever 6 is changed, or the rotation direction of the traveling motor 3 is changed, any mode other than the mode A up to that time is changed to the mode A. If it is immediately after the switching, since the immediately preceding mode is not A, the process proceeds to step S3, and it is determined whether the immediately preceding mode is the forward accelerator release mode C or the forward switchback regeneration mode E. Is determined.

If the immediately preceding mode is C or E, the current torque amount is once adjusted to 0 in step S4, and then the process returns to step S1 to input the signal again. Next, in step S2, the immediately preceding mode is determined, but this time the mode at the time of the previous signal input (step S1) was the powering mode A, so the process proceeds to step S5, and from each signal input in step S1. The determined target torque amount of the traveling motor 3 and the current torque amount are compared. If the target torque amount is larger than the current torque amount,
After the torque amount of the traveling motor 3 is increased by the preset soft start amount in step S6, the process returns to step S1. In this way, steps S1, S2, S5 and S6 are repeated until the current torque amount reaches the target torque amount, and the torque amount is increased by the soft start amount each time. On the other hand, if it is determined in step S5 that the target torque amount is less than or equal to the current torque amount, the process proceeds to step S7, where the current torque amount is reduced to the target torque amount.

That is, when the operation mode is switched from C or E to the power running mode A, the direction (sign) of the output torque of the traveling motor 3 changes as shown in FIG. In order to avoid it, the torque amount is temporarily set to 0 without shifting to the target torque amount in the mode A, and then the torque amount is gradually increased by the soft start amount to reach the target torque amount.

If it is determined in step S3 that the immediately previous mode is not C or E, the process proceeds to step S8, and it is determined whether or not the immediately previous mode was the reverse switchback regeneration mode F. The last mode was F
If so, the process returns to step S1 while maintaining the current torque amount in step S9. After that, the torque amount of the traveling motor 3 is shifted to the target torque amount in the mode A according to steps S2, S5, S6 and S7 described above.

That is, when the operation mode is switched from F to the power running mode A, as can be seen from FIG. 3, the direction (sign) of the output torque of the traveling motor 3 does not change, so the current torque amount is held as it is. Based on the torque amount, the torque amount is gradually increased by the soft start amount to reach the target torque amount, or the torque amount is reduced to the target torque amount. In this way, the operation mode is from the switchback regeneration mode F in the backward direction to the power running mode A in the forward direction.
For example, when the vehicle starts to slide down a slope, the accelerator pedal 5 is depressed, but the mode is smoothly changed at this time so that the driver can climb the slope.

If it is determined in step S8 that the immediately previous mode is not F, only the reverse powering mode B or the reverse accelerator off regeneration mode D remains as the last operating mode. Since it is not possible to directly shift to the forward powering mode A from D and D, it is judged to be abnormal at this time and step S1
After setting the current torque amount to 0 at 0, the process returns to step S1.

Similarly, the control process by the control circuit 7 when it is determined that the operation mode is the forward switchback regeneration mode E is shown in the flowchart of FIG.
This flowchart is similar to the flowchart shown in FIG. 4, except that steps S2, S3 and S8 of FIG. 4 are replaced by steps S12, S13 and S18, respectively.

First, in step S1, the output signals from the rotation sensor 4, the accelerator sensor 5a, and the forward / reverse switch 6a are input, and it is confirmed from these signals that the current mode is the mode E. Next, step S
At 12, it is determined whether the last operation mode was E. Here, if it is immediately after switching from any mode other than the mode E up to that time to the mode E, the mode immediately before is not E, so the process proceeds to step S13, and the immediately preceding mode is the power running mode A in the forward direction. It is determined whether or not

If the immediately preceding mode is A, the current torque amount is once adjusted to 0 in step S4, and then the torque amount of the traveling motor 3 is changed to mode E in steps S1, S12, S5 to S7. To the target torque amount in. That is, when the operation mode is switched from A to E, the direction (sign) of the output torque of the traveling motor 3 changes, as can be seen from FIG. 3, so the torque amount is changed to avoid a rapid change in torque. Is once set to 0 and then the torque amount is gradually increased by the soft start amount to reach the target torque amount, or the torque amount is reduced to the target torque amount.

If it is determined in step S13 that the immediately preceding mode is not A, then the procedure proceeds to step S18, in which it is determined whether the immediately preceding mode was the backward powering mode B or the forward accelerator release mode C. To be done. If the previous mode was B or C,
While maintaining the current torque amount in step S9, step S1
Return to Then, steps S12, S5, S6 and S7.
Accordingly, the torque amount of the traveling motor 3 is shifted to the target torque amount in the mode E.

That is, when the operation mode is switched from B or C to E, the direction (sign) of the output torque of the traveling motor 3 does not change, as shown in FIG. Based on the torque amount, the torque amount is gradually increased by the soft start amount to reach the target torque amount, or the torque amount is reduced to the target torque amount.

In step S18, the immediately preceding mode is set to B.
Otherwise, if it is determined that it is not C, only the accelerator-off regeneration mode D in the reverse direction or the switchback regeneration mode F in the reverse direction remains as the immediately previous operation mode, and the switchback regeneration in the forward direction from these modes D and F remains. Since it is unlikely that the mode E is directly transferred to the mode E, it is judged to be abnormal at this time, the current torque amount is set to 0 in step S10, and then the process returns to step S1.

Although not shown, when it is determined that the current driving mode of the vehicle is the power running mode B in the reverse direction, the drive control of the traveling motor 3 is performed in the same way as the flowchart of FIG. . However, in the flowchart of FIG. 4, it is determined in step S2 whether the immediately previous mode was B, in step S3 it is determined whether the immediately previous mode was D or F, and in step S8 the immediately previous mode is E. It may be determined whether or not

Further, when it is determined that the current operation mode is the accelerator-off regenerative mode C in the forward direction, the drive control of the traveling motor 3 is performed in the same way as the flowchart of FIG. However, in the flowchart of FIG. 5, it may be determined in step S12 whether or not the previous mode was C, and in step S18 whether or not the immediately previous mode was B or E.

Further, when it is determined that the current operation mode is the accelerator-off regenerative mode D in the forward direction or the accelerator-off regenerative mode F in the reverse direction, the traveling motor 3 is operated in the same manner as the flowchart of FIG. 5, respectively. Drive control is performed. However, when it is determined that the mode is the mode D, in the flowchart of FIG.
In step 12, it is determined whether or not the immediately previous mode was D, in step S13 it is determined whether or not the immediately previous mode was B, and in step S18 it is determined whether or not the immediately previous mode was A or F. do it. Further, when it is determined that the mode is the mode F, in the flowchart of FIG. 5, it is determined in step S12 whether the immediately previous mode was F, and in step S13 it is determined whether the immediately previous mode was B, In step S18, the last mode is A
Alternatively, it may be determined whether or not it was D.

In the embodiment shown in FIG. 1, the traveling motor 3 composed of an induction motor is used, but the invention is not limited to this.
A DC motor can also be used as a traction motor.

[0027]

As described above, according to the present invention, when the operation mode of the battery-powered vehicle is switched, the current torque amount of the traveling motor is first adjusted according to the operation mode switching pattern, and then the torque amount is changed. Since the traveling motor is controlled via the drive circuit so that the target torque amount is achieved, the vehicle can smoothly travel even when the operation mode is switched.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a travel control device for a battery-powered vehicle according to an embodiment of the present invention.

FIG. 2 is a diagram showing a determination condition for each operation mode in the embodiment of FIG.

FIG. 3 is a rotational speed / torque characteristic diagram of the traveling motor in each operation mode in the embodiment of FIG.

4 is a flowchart showing a control state in the embodiment of FIG.

5 is a flowchart showing a control state in the embodiment of FIG.

[Explanation of symbols]

1 ... Battery, 2 ... Power converter, 3 ... Traveling motor, 4 ...
Rotation sensor, 5 ... Accelerator pedal, 5a ... Accelerator sensor, 6 ... Forward / backward lever, 6a ... Forward / backward switch, 7 ... Control circuit.

Claims (1)

[Claims] 1. A travel motor for rotating a drive wheel of a vehicle in a normal direction or a reverse direction, a drive circuit for driving the travel motor with electric energy from a battery, and a rotation sensor for detecting a rotation speed and a rotation direction of the travel motor. An accelerator sensor for detecting a depression amount of an accelerator pedal, a forward / backward lever for setting a forward or backward traveling direction of the vehicle, a forward / backward switch for detecting a forward direction set by the forward / backward lever, Based on each output signal from the rotation sensor, the accelerator sensor and the forward / reverse switch, it is determined which one of a plurality of operation modes is preset, and the drive circuit is operated according to the operation mode. When the control mode is determined and the switching of the operation mode is determined, the output level of the traveling motor is changed according to the combination of the operation modes before and after the switching. A travel control device for a battery-powered vehicle, comprising: a control circuit that controls the drive circuit so as to mitigate a change in the torque.