JP2002225743A - Control device of electric power steering unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an electric power steering unit capable of preventing a driver's non-intentional operation of a steering mechanism which is caused by the operational deviation of a steering wheel by a driver, and improving the operability of a vehicle. SOLUTION: The rotational speed of the steering wheel 1 is detected by an operational speed sensor 3, and taken in an integration unit 15 of a detection unit 13, the rotational speed of the steering wheel 1 is integrated by the integration unit 15 to derive a rotational angle. If the rotational angle is below a predetermined reference value, the operational deviation of the steering wheel 1 is determined by a determination unit 19, and an operational deviation detection signal is outputted to a derivation unit 5. When the derivation unit 5 receives the operational deviation detection signal, the target steering speed of a steering motor 7 is set to be zero, the rotation of the steering motor 7 is stopped, and the operation of the steering mechanism is prevented when any operational deviation occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric power steering system for electrically steering a steering wheel of a vehicle by electrically connecting a steering wheel to a steering mechanism of the vehicle and controlling a driving motor of the steering mechanism in accordance with the operating speed of the steering wheel. The present invention relates to a steering control device.

[0002]

2. Description of the Related Art A picking forklift 51, which is one of the conventional cargo handling vehicles, is configured as shown in FIG. 3, for example.

[0003] That is, an operator stands on a rear portion of a vehicle body 53 (here, a driver's cab 57 described later) which drives by driving a motor (not shown) by a driving battery, and operates a handle 61 toward the mast 55. A pair of left and right masts 55 are erected, and a driver's cab 57 on which the operator rides is provided so as to be vertically movable along the mast 55, and a pair of left and right forks 59 is attached to the driver's cab 57, The fork 5 is operated by the operator.
9 moves up and down integrally with the cab 57.

By the way, in such a picking forklift 51, a handle 61 for steering a vehicle body 53 is provided.
Since it is arranged on the driver's cab 57 that moves up and down, it is difficult to mechanically connect the steering wheel 61 and a steering mechanism (not shown) of the vehicle body 53 by a connecting shaft, and as a result, the steering wheel 61 is attached to the connecting shaft Since it is difficult to use a power steering configured to assist a steering torque by a steering motor, the following electric power steering is used.

In this type of electric power steering,
The handle shaft and the steering mechanism of the vehicle body 53 are electrically connected, so that the steering operation can be transmitted to the steering mechanism to change the direction of the steered wheels regardless of the arrangement position of the handle. More specifically, for example, as shown in FIG. 4, the rotation speed at the time of the rotation operation of the handle 61 is detected by an operation speed sensor 63 composed of, for example, an encoder, and a detection signal is output to the derivation unit 65. A target steering speed corresponding to the rotation speed of the steering wheel 61, that is, the rotation speed of the steering motor 67 that drives the steering mechanism is derived. Then, the rotation speed of the steering motor 67 is detected by a motor rotation speed sensor 69 and is taken into a motor drive unit 71 composed of a chopper circuit and the like, and the rotation speed of the steering motor 67 matches the target steering speed. The steering motor 67 is controlled so that the steering mechanism is driven, and the direction of the steered wheels is changed.

[0006]

However, in such an electric power steering, the steering wheel 61 is always used.
Since the steering motor 67 is controlled in accordance with the rotation speed of the steering wheel, the steering motor 67 is rotated in accordance with the rotation of the steering wheel 61 even when the steering wheel 61 slightly moves during traveling, and the steering mechanism is driven. Is done. Therefore, even when a slight movement of the steering wheel that the driver does not intend, that is, when the steering wheel is shaken, the steering motor 67 rotates, and the steering mechanism is driven against the intention of the driver, and the direction of the steered wheels changes. There was a problem that would.

[0007] To prevent this, for example, the handle 6
It is conceivable to stop the rotation of the steering motor 67 when the first rotation speed is lower than the predetermined speed so that the steering mechanism is not driven.
For example, when it is necessary to slowly operate the handle 61 in order to finely adjust the position of the fork to a predetermined loading position, the steering motor 67 does not rotate, so that the vehicle body 53 can be steered as intended by the driver. The disadvantage of disappearing occurs.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a control device for an electric power steering which prevents unintentional steering by a driver due to a steering shake and improves operability of a vehicle. The purpose is to provide.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention detects an operation speed at the time of turning operation of a steering wheel, derives a target steering speed from the detected operation speed, and performs a steering operation on a vehicle. An electric power steering control device that controls the drive motor such that the rotation speed of the drive motor of the mechanism matches the target steering speed detects an operation shake of a predetermined amount or less when the handle is rotated. And a detector for setting the target steering speed to zero during the period.

According to such a configuration, when it is detected that the operation amount is equal to or less than the predetermined amount during the turning operation of the steering wheel, that is, when the operation of the steering wheel is shaken, the target steering speed is set to zero by the detecting unit. Therefore, the rotation of the driving motor is stopped, and the driving of the steering mechanism is stopped. Therefore, even when the steering wheel is operated differently from the steering wheel operation originally intended by the driver, the steering mechanism can be prevented from being driven, and the operability of the vehicle can be improved. . Further, unnecessary power supply to the drive motor during operation fluctuation can be avoided, so that power consumption of the battery can be reduced.

Further, the present invention provides an operation speed detection unit for detecting the operation speed, a derivation unit for deriving the target steering speed, a rotation speed detection unit for detecting the rotation speed, and wherein the rotation speed is the target speed. A control unit that controls the drive motor so as to match a steering speed, wherein the detection unit detects an output of the operation speed detection unit when the operation speed detected by the operation speed detection unit is not zero. An integrator that starts integration, and a deriving unit that compares and determines the integrated value obtained by the integrator with a predetermined reference value and sets the target steering speed to zero until the integrated value exceeds the reference value. And a determination unit that outputs a detection signal.

According to such a configuration, the operation amount of the steering wheel is derived by integrating the operation speed of the steering wheel. If the operation amount is equal to or less than a predetermined reference value, the target steering speed is set to zero and the steering mechanism is driven. Since it is not performed, it is possible to reliably detect the operation blur of the steering wheel regardless of the operating speed of the steering wheel, and it is possible to improve the operability of the vehicle. Further, since it is not necessary to separately provide a sensor or the like for detecting an operation blur, the cost of the apparatus can be reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electric power steering of a picking forklift will be described with reference to FIGS. 1 is a block diagram of a control device for an electric power steering, and FIG. 2 is a timing chart for explaining the operation.

The basic structure of the picking forklift 51 in this embodiment is almost the same as the conventional one shown in FIG. 3, so that in the following description, FIG. A control device for an electric power steering will be mainly described.

[0015] As shown in FIG. 1, the operation speed during rotational operation of the steering wheel 1, i.e. the rotational speed V _h is, for example, is detected by the operation speed sensor 3 consisting of an encoder, derivation unit 5
At the target steering speed V _m corresponding to the rotation speed V _h ,
That is, the rotation speed of the steering motor 7 that drives the steering mechanism (not shown) of the vehicle body 53 (FIG. 3) is derived. Note that in order to derive the target steering speed V _m is the handle 1
Rotation speed V may be calculated based on a predetermined calculation formula such as _h in multiplying the coefficient, or the rotational speed V _h of the steering wheel 1, the target steering speed V corresponding to each of the rotational speed V _h of
Create a target steering speed table tabulating the _m may be stored in a memory (not shown), so as to read out from the target steering speed table by reading unit to the target steering speed V _m corresponding to the rotational speed V _h of the steering wheel Is also good. Here, the operation speed sensor 3 corresponds to the operation speed detection unit of the present invention, and the steering motor 7 corresponds to the drive motor of the present invention.

[0016] Then, the motor drive unit 9 to the target steering speed V _m derived by the deriving unit 5 is composed of a chopper circuit
The motor drive unit 9 outputs a motor rotation speed sensor 1 that is a rotation speed detection unit including, for example, an encoder.
1 so that the rotation speed of the steering motor 7 detected by the control unit 1 matches the target steering speed.
Is controlled. Here, the chopper circuit of the motor drive unit 9 is configured by, for example, an inverter including a plurality of switching elements, and the chopper circuit according to the present invention is controlled by the chopper circuit and a control signal output circuit that outputs a switching control signal to each switching element. Unit is configured.

The control device includes a handle 1
Of the steering wheel 1
A detection unit 13 for detecting a crush is provided.
You. That is, in the detection unit 13, the operation speed sensor 3
Speed V of the steering wheel 1 detected by_hIs the integral part
15 and the clear signal output unit 17, and the integration unit 1
5, the rotation speed V of the handle 1_hThe integral of
Rotation angle φ of handle 1 _hIs derived and output to the determination unit 19.
Is forced.

The judging section 19 compares the rotation angle φ _h with a predetermined reference value φ _s and sets the rotation angle φ _h
There when: the reference value phi _s is steering in this case determines that the operation blur, and outputs an operation blur detection signal to the deriving unit 5. Then, when the operation shake detection signal is input, the deriving unit 5 sets the target steering speed _Vm to zero, stops the rotation of the steering motor 7, and prevents the steering mechanism from being driven.

The operating speed sensor 3 controls the steering wheel 1.
If it is detected rotational speed V _h of is zero, it is output clear signal from the clear signal output section 17 to the integrator 15, derived integrated value by the integration unit 15, i.e. the rotational angle φ
_h is cleared. That is, when the rotation speed V _h of the steering wheel 1 becomes zero, the integration unit 15 clears the rotation angle φ _h once derived, and then inputs the rotation speed V _h
It is adapted to start the derivation of the rotation angle φ _h from _h. In this way, only the rotation angle phi _h time wheel 1 is continuously rotated operation is derived, the rotation angle phi _h is prevented from being accumulated unnecessary.

The above-mentioned reference value φ _s is desirably set based on the rotational angle of the steering wheel 1 which causes the operation blurring obtained by an experiment or the like. In addition, this reference value φ
_s may be stored in a memory such as a ROM of the determination unit 19, or may be variably set according to the road on which the forklift travels, work conditions, and the like.

Next, the control operation of the power steering by the control device will be described with reference to FIG. As shown in FIG. 2, the rotational speed V _h of the steering wheel 1 until the time T1 to become less than zero, for continuously clear signal to the integrator 15 from the clear signal output section 17 is output, it is derived by the integrator 15 Rotation angle φ _h remains zero. At this time, since the derived rotation angle phi _h is less than the reference value phi _s, are output operations shake detection signal by the judging portion 19, the target steering speed V _m is set to zero in the derivation unit 5. As a result, the steering motor 7 is kept stopped, and the steering mechanism remains stopped.

[0022] Then, the handle 1 at time T1 in one direction (e.g., clockwise) when the rotational speed V _h is started rotating to go increased to the positive side, the clear signal from the clear signal output section 17 the output is stopped, the integration of the rotational speed V _h of the steering wheel 1 is started by the integrator 15, the rotation angle phi _h in one direction of the handle 1 is derived. here,
From time T1 to T2, since the integral rotation angle phi _h is less than the reference value phi _s, but the lead-out portion 5 from the determination unit 19 operation shake detection signal continues to be outputted, past the time T2 since the rotation angle phi _h is greater than the reference value phi _s, the output of the operation shake detection signal is stopped. As a result, the derivation unit 5
Target steering velocity V _m corresponding to the rotational speed V _h of the steering wheel 1 is derived by the rotational speed of the steering motor 7 by the motor rotational speed sensor 11, the target steering speed V _m
The steering motor 7 is rotated to match
The steering mechanism is driven.

Subsequently, at time T3, when the rotation of the steering wheel 1 stops and the rotation speed _Vh becomes zero, the clear signal output unit 1
7 outputs a clear signal to the integrator 15.
Rotation angle phi _h of the steering wheel 1, which is accumulated is cleared in. Further, since the rotational speed V _h of the steering wheel 1 is zero, the integrated value becomes zero, the output operation shake detection signal from the determination unit 19 in association with this, the target steering speed V _m is zero at the outlet portion 5 Is set.

Thereafter, between time T4 and T5, handle 1
Is rotated in one direction and then reversed in the other direction
It is operated to rotate, but it was derived at this time
Rotation angle φ_hIs the reference value φ_sThe determination unit 19
The steering operation at this time is determined to be
Then, the operation shake detection signal is output to the derivation unit 5.
Thereby, when the steering wheel 1 is being rotated.
Even the rotation angle φ _hIs the reference value φ_sIf
Has the target steering speed V_mStearin is set to zero
The motor 7 is stopped and the steering mechanism is not driven.
No.

[0025] Then, the handle 1 is the other direction from the time T6 to T8 (e.g., counterclockwise direction) when rotated, the rotation angle phi _h in the other direction derived from the rotational speed V _h at that time
Is input to the determination unit 19. In this case, the period from time T7 to T8 from the rotation angle phi _h exceeds the reference value phi _s, is output stop operation shake detection signal from the determination unit 19 during this period, whereby the derivation unit 5 target steering velocity V _m corresponding to the rotational speed V _h of the steering wheel 1 is derived, the rotational speed of the steering motor 7 by the motor rotational speed sensor 11, the steering motor 7 is rotated to match the target steering speed V _m The steering mechanism is driven. Since the steering wheel 1 has not been rotated since time T8, the steering mechanism is not driven.

[0026] Therefore, according to the above embodiment, when the rotation angle phi _h during rotational operation of the steering wheel 1 that has been detected is less than a predetermined reference value phi _s, handle 1
Is determined to have occurred, and the target steering speed V
_{Since m} is set to zero, the rotation of the steering motor 7 is stopped, and the driving of the steering mechanism is stopped. Therefore, when the steering of the steering wheel 1 is shaken, it is possible to prevent the vehicle from being steered against the driver's intention, and to improve the operability of the vehicle. Further, unnecessary power supply to the steering motor 7 at the time of occurrence of operation blur can be avoided, so that power consumption of the battery can be reduced.

[0027] At this time, since the derived rotation angle phi _h of the steering wheel 1 by integrating the rotational speed V _h of the steering wheel 1, the rotation speed V _h of the steering wheel 1 is a case slow, the handle 1 Operation blur can be reliably detected. Further, since it is not necessary to separately provide a sensor or the like for detecting an operation blur, the cost of the apparatus can be reduced.

Further, as the steering motor 7 used in the above-described embodiment, any of an AC motor and a DC motor can be used, and the motor drive unit 9 is not limited to the one comprising the above-mentioned chopper circuit. Further, a microcomputer may be used as the detection unit 13 or an analog control circuit including a discrete element may be used.

Further, in the embodiment described above, the running of the forklift is fixed reference value phi _s, it may be varied by the running speed of the forklift.

In the above-described embodiment, the case where the present invention is applied to a picking forklift is described. However, the present invention is not limited to this. For example, other types of forklifts such as a counterbalance type forklift, or a passenger car In other words, the present invention can be applied to a vehicle equipped with an electric power steering in which the steering wheel and the steering mechanism are electrically connected as described above.

Further, when the rotation speed of the drive motor can be calculated (estimated) by, for example, the applied voltage and current of the motor, the motor rotation speed sensor 11 is replaced by the applied voltage and current of the motor. Means for calculating (estimating) the rotation speed may be provided.

The present invention is not limited to the above-described embodiment, and various changes other than those described above can be made without departing from the gist of the present invention.

[0033]

As described above, according to the first aspect of the present invention, when it is detected that the operation amount is less than a predetermined amount during the turning operation of the steering wheel, that is, the steering operation blur occurs. At times, since the target steering speed is set to zero, the rotation of the drive motor is stopped, and the drive of the steering mechanism is stopped. Therefore, even in the case where the steering operation is different from the steering operation originally intended by the driver, the steering mechanism can be prevented from being driven,
The operability of the vehicle can be improved. Furthermore, unnecessary power supply to the drive motor can be avoided when the operation blur occurs, so that the power consumption of the battery can be reduced.

According to the second aspect of the present invention, the operation amount of the steering wheel is derived by integrating the operation speed of the steering wheel. When the operation amount is equal to or less than a predetermined reference value, the target steering speed is set to zero. Since the steering mechanism is not driven, the steering shake of the steering wheel can be reliably detected regardless of the steering wheel operating speed, and the operability of the vehicle can be improved. Further, since there is no need to separately provide a sensor or the like for detecting an operation blur, the cost of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control device for an electric power steering according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining an operation according to the embodiment of the present invention;

FIG. 3 is a perspective view of a picking forklift serving as a background of the present invention.

FIG. 4 is a block diagram of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 handle 3 operation speed sensor (operation speed detection unit) 5 derivation unit 7 steering motor (drive motor) 9 motor drive unit (control unit) 11 motor rotation speed sensor (rotation speed detection unit) 13 detection unit 15 integration unit 19 judgment Department

Claims (2)

[Claims] An operation speed during a rotation operation of a steering wheel is detected, a target steering speed is derived from the detected operation speed, and a rotation speed of a drive motor of a steering mechanism in the vehicle matches the target steering speed. An electric power steering control device for controlling the drive motor, further comprising a detection unit for setting the target steering speed to zero while detecting an operation shake of a predetermined amount or less when the steering wheel is rotated. A control device for an electric power steering, comprising: 2. An operation speed detection unit for detecting the operation speed, a derivation unit for deriving the target steering speed, a rotation speed detection unit for detecting the rotation speed, and the rotation speed coincides with the target steering speed. A control unit that controls the drive motor so that the operation speed detection unit starts integrating the output of the operation speed detection unit when the operation speed detected by the operation speed detection unit is not zero. An integration unit, and a comparison signal between the integration value obtained by the integration unit and a predetermined reference value, and until the integration value exceeds the reference value, sends a detection signal to the derivation unit to set the target steering speed to zero. The control device for an electric power steering according to claim 1, further comprising: a determination unit that outputs the signal.