JP2000115919A - Control equipment of forward and reverse drive of industrial vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide control equipment of going forward and going backward of an industrial vehicle which especially eliminates time lag and can quickly control forward and reverse drive of a vehicle, regarding an industrial vehicle like a battery fork lift. SOLUTION: Regarding control equipment of an industrial vehicle in the neutral state, an exciting current is made to flow in an excitating coil 15 in the full line arrow direction or in the dotted line arrow direction, a transistor Q8 for regeneration is turned on, a DC motor 12 is rotated, and a voltage between armature windings of the DC motor 12 is detected with a voltage detecting part V and outputted to a CPU 14. The CPU uses the direction of the current flowing in the excitating coil 15 and the output voltage of the voltage detecting part V, judges whether the rotating direction of the DC motor 12 coincides with the direction of the exciting current, and performs quick processing for forward and reverse motion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an industrial vehicle, and more particularly, to a control device for a forward / reverse drive when the vehicle is switched between forward and reverse.

[0002]

2. Description of the Related Art Today, industrial vehicles such as battery forklifts replace mechanical mechanisms with electrical circuits and mechanically complicated controls with electrical controls. For example,
The forward traveling or the backward traveling of the vehicle is performed by chopper control of a transistor circuit, and the switching control between forward and backward is performed by switching the direction of the current flowing through the exciting coil.

FIG. 3 is a circuit diagram of a motor drive circuit for explaining control of a conventional example in an industrial vehicle. In FIG. 1, reference numeral 1 denotes a battery power supply, which supplies a predetermined voltage to a motor drive circuit 4 via a fuse 2 and a switch 3. The motor drive circuit 4 includes a DC motor 5, a driving transistor Q1, a regenerating transistor Q2, and a current sensor 6.

The above-described DC motor 5 is a shunt DC motor, and the excitation coil 7 is driven and controlled by transistors Q1 to Q4. The current flowing through the exciting coil 7 is detected by the current sensor 8. Normally, the rotational force of the DC motor 5 is used for traveling of the industrial vehicle, and the traveling direction is switched by switching the direction of the current flowing through the exciting coil 7.

For example, let us consider a case where the transistors Q4 and Q5 are driven, a current in the direction indicated by a solid line arrow is applied to the exciting coil 7, and the DC motor 5 is driven to run the vehicle.
It is assumed that a rotation sensor is not used for the DC motor 5 in the conventional example.

First, when the vehicle starts moving, the current determined by the accelerator operation is supplied to the exciting coil 7, and at the same time, a sufficiently low current is supplied to the driving transistor Q1. By this processing, an armature current flows through the DC motor 5, and a voltage generated at both ends of the DC motor 5 is detected. For example, when there is no potential difference between both ends of the DC motor 5, the excitation direction and the DC motor 5
Are determined to be the same. in this case,
If there is a forward command, the vehicle will travel in the same direction thereafter. on the other hand,
When the potential difference between both ends of the DC motor 5 is large, the direction of excitation does not match the rotation direction of the DC motor 5. Therefore,
In this case, regeneration control is performed thereafter.

[0007] Even when the potential difference between both ends of the DC motor 5 is large, regeneration control is not performed and PLG (plunging) is performed.
In some cases, the control is shifted to the control to stop the rotation of the DC motor 5 in the same direction.

[0008]

In the above-described conventional battery forklift control device, it is determined whether the DC motor 5 is rotating in the direction corresponding to the direction of supply of the exciting current.
The drive control (powering control), the regenerative control, and the PLG control of the DC motor 5 are determined according to the determination result, and the control is shifted to the corresponding control.

Therefore, in the conventional battery forklift control device, it takes time to determine whether the vehicle is moving forward or backward,
In particular, a time lag was required to determine the relationship between the direction of supply of the exciting current and the direction of rotation of the DC motor.

[0010] The present invention provides a method for controlling forward and backward movement of an industrial vehicle.
It is an object of the present invention to provide a forward / backward control device for a battery forklift that eliminates a time lag and quickly controls forward / backward travel of a vehicle, and a control method thereof.

[0011]

According to the first aspect of the present invention, there is provided an exciting current supply means for supplying a small current to an exciting coil when a forward / reverse instruction of an industrial vehicle is in a neutral state. A circuit forming means for forming a circuit for flowing an armature current to a DC motor excited by an exciting coil; detecting a voltage of an armature winding of the DC motor; detecting a magnitude of the voltage and a current flowing through the exciting coil; Determining means for determining the direction of rotation of the DC motor from the direction, and control means for performing regenerative control or powering control in accordance with the direction of rotation of the DC motor determined by the determining means and the direction of current flowing through the exciting coil. This can be achieved by providing a forward / backward control device for an industrial vehicle.

Here, the exciting coil driving means uses, for example, a bridge-shaped transistor circuit, and controls the driving of the transistor to flow a small current through the exciting coil. The direction of the current may be any direction. . Further, the circuit forming means is configured to cause a current to flow through the armature winding of the DC motor, and is formed by, for example, turning on a regenerating transistor connected in parallel to the armature winding.

In the above configuration, when the DC motor rotates in any direction, an electromotive force is generated in the DC motor, and a potential difference is generated between both ends of the armature winding. The potential difference is detected by a voltage detecting unit. The rotation direction of the DC motor is determined by the determination means composed of

[0014] With this configuration, the control means obtains information on the rotation direction of the DC motor obtained by the above determination,
It is possible to immediately determine the corresponding regenerative processing or powering processing from the direction of the current flowing through the exciting coil, and to quickly perform forward and backward control of the industrial vehicle.

According to a second aspect of the present invention, in the first aspect of the present invention, the judging means performs a powering process when the rotation direction of the DC motor and the current direction of the exciting coil are the same, for example. The regenerative processing is performed when the rotation direction of the motor is different from the current direction of the exciting coil.

In this case, the rotation direction of the DC motor is the same as the current direction of the exciting coil. For example, if there is a forward command, power running processing is performed, and the rotation direction of the DC motor and the current direction of the exciting coil are different. For example, if there is a forward instruction, a regeneration process is performed. In the above example, if there is a reverse command, the powering process and the regenerative process are reversed.

According to the third aspect of the present invention, the above object is provided.
An exciting current supply process for supplying a small current to an exciting coil when a forward / reverse instruction of an industrial vehicle is in a neutral state, and a circuit formation for forming a circuit for passing an armature current to a DC motor excited by the exciting coil. Processing, detecting a voltage of an armature of the DC motor, determining a rotation direction of the DC motor from a magnitude of the voltage and a direction of a current flowing through the exciting coil, and a DC motor determined by the determination processing. This can be achieved by providing a method for controlling the forward / backward movement of an industrial vehicle that performs a regenerative process or a powering process in accordance with the rotation direction of the motor and the direction of the current flowing through the exciting coil.

The present invention is an application of the invention for controlling the forward / backward movement of an industrial vehicle according to the first aspect of the present invention to a forward / backward control method. Information on the direction of rotation of the DC motor
From the direction of the current flowing through the exciting coil, the corresponding regenerative processing or powering processing can be immediately performed to quickly control the forward / backward movement of the industrial vehicle.

According to a fourth aspect of the present invention, in the invention according to the third aspect, the determination processing is performed, for example, when the rotation direction of the DC motor and the current direction of the exciting coil are the same, the power running processing is performed. The regenerative processing is performed when the rotation direction of the motor is different from the current direction of the exciting coil.

The present embodiment is a process corresponding to claim 2 described above, and is applied to a method for controlling the forward and backward movement of an industrial vehicle.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a circuit diagram illustrating an example of a control device for an industrial vehicle according to this embodiment, for example, a battery forklift. In FIG. 1, a battery 10 is a battery mounted on a battery forklift (not shown), and outputs a predetermined voltage (for example, 24 V) from the battery 10 to a motor drive circuit 11. The motor drive circuit 11 includes a DC motor 12, a running transistor Q7, a regenerating transistor Q8, and a current sensor (CSDA) 13.

The driving transistor Q7 is a transistor for supplying an armature current to the DC motor 12 when the DC motor 12 is driven, and is turned on / off according to a control signal output from the CPU 14. The regenerating transistor Q8 is a switch for regenerating the driving force of the DC motor 12 to the power source when reversing the rotation direction of the DC motor 12, and is turned on / off in accordance with a control signal output from the CPU 14 as described above. Drive.

A current sensor (CSDA) 13 is a sensor for detecting the value of the armature current supplied to the DC motor 12. Note that a voltage detection unit V is provided in parallel with the DC motor 12, and detects a voltage value at both ends of the DC motor 12. The data of the current value detected by the current sensor (CSDA) 13 and the voltage data detected by the voltage detection unit V are supplied to the CPU 14.

The CPU 14 performs the control of this embodiment according to a program stored in a ROM (not shown), and at a predetermined timing, the running transistor Q7 and the regenerating transistor Q7.
8 and a control signal to transistors Q9 to Q12 to be described later.

On the other hand, the excitation current is supplied to the DC motor 12 by the excitation coil 15. A current is supplied to the exciting coil 15 by controlling the driving of the four transistors Q9 to Q12 formed in a bridge shape, and the transistors Q9 to Q12 are controlled by the aforementioned CP.
This is performed by a control signal output from U14. For example, when flowing a current in the direction of the solid line arrow of the exciting coil 15,
The CPU 14 outputs a control signal to the gates of the transistors Q10 and Q11, turns on the transistors Q10 and Q11, and passes the current to the exciting coil 15. When a current is supplied to the exciting coil 15 in the direction of the dotted line arrow, the CPU
Reference numeral 14 outputs a control signal to the gates of the transistors Q9 and Q12, drives the transistors Q9 and Q12, and allows the current to flow to the exciting coil 15.

The current sensor (CSDF) 16 is a sensor for detecting an exciting current flowing through the exciting coil 15, and data of a current value detected by the current sensor (CSDF) 16 is also supplied to the CPU 14.

The running transistor Q7, the regenerating transistor Q8, and the transistors Q9 to Q12 are provided with diodes D7 to D12, respectively, in parallel with each other, so that a bypass when a reverse current flows through the corresponding transistor. Used as

The battery 10 and the motor drive circuit 1
A fuse 17 and a switch 18 are provided between the two, and the power supply from the battery 10 is stopped when, for example, a circuit abnormality occurs.

The processing operation of the above configuration will be described below.

FIG. 2 is a flowchart for explaining the processing operation of this embodiment. It is assumed that the switch 18 is in an on state at the initial stage, and power is supplied to the motor drive circuit 11 from the battery 10. Normally, the driving transistor Q7 is turned on by a control signal output from the CPU 14, an armature current is supplied to the DC motor 12, and the direction of the current flowing through the exciting coil 15 is determined by the CPU 14.
, The rotation direction of the DC motor 12 is determined, and the battery forklift travels forward or backward.

Here, it is assumed that the vehicle (battery forklift) is traveling in a certain direction (forward direction or reverse direction), and in this state, when the direction indication is set to neutral by lever operation or accelerator operation. The CPU 14 knows the neutral setting from a signal supplied from a sensor (not shown) (step (hereinafter, referred to as S) 1 is YES).

Next, the CPU 14 applies a weak current (small current) to the exciting coil 15 (S2). The current flowing at this time is extremely small, and the direction of the flowing current may be either a solid line direction or a dotted line direction. That is, the CPU 14 controls the transistors Q10 and Q11 or the transistors Q9 and Q11.
12 to supply a control signal to a current sensor (CSD
F) While detecting the current value at 16, for example, a constant weak current is passed.

Next, a control signal is output from the CPU 14 to the regenerating transistor Q8 to turn on the regenerating transistor Q8 (S3). Through the above processing, a circuit is formed in which the exciting current is supplied to the DC motor 12 and the armature current flows. Therefore, if the DC motor 12 is rotating at this time, an electromotive force is generated.

Therefore, the CPU 14 confirms the voltage value supplied from the voltage detector V (S4). here,
When the detected voltage of the voltage detector V is equal to or higher than the predetermined value (S4: YES), the CPU 14 performs the regenerative control (S5). On the other hand, when the detection voltage of the voltage detection unit V is equal to or lower than the predetermined value (S
4 is NO), and the CPU 14 thereafter performs normal traveling processing (S6).

Here, when the detection voltage of the voltage detection unit V is equal to or higher than a predetermined value, the DC motor 12 is rotating in the opposite direction to the exciting current, and the DC motor 12 acts as, for example, a generator, and It is determined that the voltage between both ends of the motor 12 has become equal to or more than the predetermined value, and the above-described regenerative control is performed (S5).
On the other hand, when the detection voltage of the voltage detection unit V is equal to or less than the predetermined value, for example, when there is almost no potential difference, it is determined that the DC motor 12 is rotating in the same direction with respect to the exciting current, and the normal traveling process ( Powering process) (S6).

For example, the CPU 14 drives the above-described transistors Q10 and Q11 (at this time, the transistors Q9 and Q12 are turned off), and supplies an exciting current in the solid line direction to the exciting coil 15. In this state, if data of a voltage value equal to or less than a predetermined value (for example, a voltage value close to 0 V) is received from the voltage detection unit V, it is determined that the supply direction of the excitation current and the rotation direction of the DC motor 12 are the same. However, when a forward command is issued by a later lever operation or the like, the exciting current is increased as it is, and the process immediately shifts to the normal drive. In addition, when a backward instruction is given by a later lever operation or the like, a regeneration instruction is issued, and regeneration processing can be performed immediately.

On the other hand, the transistors Q9 and Q12 are driven (at this time, the transistors Q10 and Q11 are set to the off state), and an exciting current in the direction of the dotted line flows through the exciting coil 15. Then, in this state, if data of a voltage value equal to or more than a predetermined value is received from the voltage detection unit V, it is understood that the supply direction of the exciting current and the rotation direction of the DC motor 12 are opposite, and if there is a forward instruction thereafter, immediately By changing the excitation direction,
Forward traveling can be performed. In the case of a reverse command, it is possible to respond by immediately changing the excitation direction and issuing a regenerative command.

By controlling as described above, the rotational direction of the DC motor 12 can be known in a state where the vehicle direction is neutralized by lever operation or the like. Judgment of the rotation direction can be made immediately, and quick forward and backward control can be performed without causing a time lag.

That is, the processing from the judgment (S1) to the judgment (S4) in the flowchart shown in FIG. 2 can be performed in a neutral state, and the rotation direction of the DC motor 12 is known during the neutral period. Regenerative control or powering control can be immediately executed.

When performing the above-described regenerative control, the above-described PLG (plunging) control may be performed instead of the regenerative control.

Although the description of this embodiment has been made with reference to the forward / backward processing of the battery forklift, the present invention is not limited to the battery forklift and may be applied to the forward / backward control of other industrial vehicles.

[0043]

As described above, according to the industrial vehicle forward / reverse control device of the present invention, the rotation direction of the motor can be known in the neutral state.

Also, since the above-mentioned time lag is eliminated,
Faster forward / backward control of the industrial vehicle can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a circuit configuration of a forward / reverse control device for an industrial vehicle according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a processing operation of the embodiment.

FIG. 3 is a diagram illustrating a circuit configuration of a conventional industrial vehicle control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Battery 11 Motor drive circuit 12 DC motor 13 Current sensor (CSDA) 14 CPU 15 Exciting coil 16 Current sensor (CSDF) 17 Fuse 18 Switch Q7-Q12 Transistor V Voltage detector

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F333 AA02 AB13 DB07 FA18 FA20 FA32 FE04 FE09 5H115 PA01 PC06 PG05 PI16 PI29 PO02 PU04 PV03 PV23 QE10 QE13 QH08 QI04 QI05 QN03 RB19 RB20 SE03 TO01 TO12 TO13 TO22 TO30 TR05 TZ

Claims (4)

[Claims] 1. An exciting current supply means for supplying a small current to an exciting coil when a forward / reverse instruction of an industrial vehicle is in a neutral state, and a circuit for supplying an armature current to a DC motor excited by the exciting coil. A circuit forming means for forming; a detecting means for detecting a voltage of an armature winding of the DC motor, and determining a rotation direction of the DC motor based on a magnitude of the voltage and a direction of a current flowing through the exciting coil; The rotation direction of the DC motor determined by the means,
Control means for performing regenerative control or power running control in accordance with the direction of the current flowing through the exciting coil. 2. The method according to claim 1, wherein the determining unit performs a powering process when a rotation direction of the DC motor and a current direction of the exciting coil are the same, and regenerates when a rotation direction of the DC motor and a current direction of the exciting coil are different. The forward / backward control apparatus for an industrial vehicle according to claim 1, wherein the processing is performed. 3. An exciting current supply process for supplying a small current to an exciting coil when a forward / reverse instruction of an industrial vehicle is in a neutral state, and a circuit for passing an armature current to a DC motor excited by the exciting coil. Forming a circuit; forming a circuit; detecting a voltage of an armature of the DC motor; and determining a rotation direction of the DC motor based on a magnitude of the voltage and a direction of a current flowing through the exciting coil. Rotation direction of the DC motor determined by
Performing a regenerative process or a powering process in accordance with a direction of a current flowing through the exciting coil. 4. A power running process when the rotation direction of the DC motor and the current direction of the exciting coil are the same, and the regenerating process is performed when the rotation direction of the DC motor and the current direction of the exciting coil are different. The method for controlling the forward / backward movement of an industrial vehicle according to claim 3, wherein the processing is performed.