JPH10119803A - Handle angle correcting device and vehicle in power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the position slippage of a handle owing to a minute regulation of the handle in the straight running condition, in a device furnishing a function to stop the handle position correction when the handle operating speed is slower than a set value. SOLUTION: The dicision whether a handle operating speed is slower than a set value or not is carried out by using the deflection ΔR(=|R-R1|) between the handle angle R1 before a specific time n.t0 and the present handle angle R, that is, the steering angle speed of a steering wheel. When the handle operating speed is decided to be slower than the set value (S50, S60), but the tire turning angle is within the straight advancing scope (S70), a knob position correction is carried out as far as the car speed is not less than 5km/h (S80). When the car speed is less than 5km/h when the tire reaction is large, the knob position correction is prohibited in order to prevent the deterioration of the handle feeling. In order to carry out the decision of the handle operation speed correctly from the steering speed, deciding values r1 and r2 which are different from the opening and the closing of a valve are prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering angle correction device and a vehicle for a power steering device for correcting a positional difference between a steering wheel angle and a steering wheel turning angle in a vehicle such as a forklift equipped with a power steering device. It is about.

[0002]

2. Description of the Related Art Conventionally, as a power steering device,
2. Description of the Related Art An all-hydraulic power steering device that supplies an oil amount corresponding to an operation amount of a steering wheel to a steering cylinder to steer a steered wheel is known.

For example, in an industrial vehicle such as a forklift,
A knob is provided on the handle so that the handle can be operated with one hand while performing a cargo handling operation or the like. For this reason, the position of the knob may be used as a guide for determining whether or not the turning angle of the steered wheels is in the straight traveling posture. However, the amount of oil discharged in accordance with the operation amount of the steering wheel is not always used for driving the steering cylinder. When the orbit roll efficiency (actual discharge amount / theoretical discharge amount) decreases, the position of the knob and the A deviation occurs in the positional relationship with the steering angle of the steered wheels. The decrease in the orbit roll efficiency is caused when the steering wheel is operated at a low speed or due to an oil leak in a hydraulic system such as a steering cylinder.

[0004] For example, Japanese Patent Publication No. 3-30544, Japanese Patent Publication No. 4-24270, and Japanese Utility Model Publication No. 7-5364 disclose a steering wheel angle correction device for correcting a deviation of a steering wheel angle from a steering angle of a steered wheel. Have been. FIG.
1 shows a steering wheel angle correction device disclosed in Japanese Utility Model Publication No. 7-5364.

[0005] As shown in FIG. 1, a fully hydraulic power steering device 51 is operated by a steering wheel 52.
A steering unit 54 having an S control valve 53 and a steering cylinder 5 for steering a steered wheel (not shown)
5 and hydraulic lines 56 and 57 connecting the steering unit 54 and the steering cylinder 55.
One of the hydraulic lines 56 and 57 serves as a supply line for supplying pressurized hydraulic oil from the hydraulic pump 58 during steering according to the steering direction of the handle 52, and the other line returns oil to the tank 59. Return line. An electromagnetic control valve 60 is provided in the middle of both hydraulic lines 56 and 57.

The controller 61 receives a handlebar rotation angle signal θabs from a handlebar position sensor 62 and a cylinder stroke signal s from a cylinder position sensor 63. The controller 61 outputs the steering wheel rotation angle signal θabs
From the signal s, the target cylinder stroke xg and the target cylinder stroke x
When the deviation from g exceeds an allowable value, the electromagnetic control valve 60 is opened.

When the electromagnetic control valve 60 is opened,
A part of the hydraulic oil flows from one supply line of the hydraulic lines 56, 57 to the other return line to the tank 59, the handle 52 is idled, and the handle position is a normal position corresponding to the steering angle of the steered wheels. The position of the steering wheel is corrected until the correction is made.

In this conventional device, the handle position sensor 6
2 is differentiated by a differentiating circuit and converted into a speed signal proportional to the handle rotation speed. When the steering wheel rotation speed is lower than the set value, the position of the steering wheel is not corrected even if the deviation exceeds the allowable value. For this reason, it is possible to eliminate a feeling of strangeness of the steering feeling in which the change rate of the steering angle of the steered wheels becomes too large with respect to the steering operation at the time of the steering operation at a low speed.

[0009]

During straight running, the steering wheel 52 is operated while finely adjusting the steering wheel 52. At this time, however, the steering wheel operating speed is slow, so that the steering wheel position is not corrected. As a result, there is a problem that the position of the knob 52a gradually shifts. A shift in the position of the knob 52a during driving causes an uncomfortable feeling in operating the steering wheel.

When the vehicle is stopped without turning the steering wheel while the vehicle is traveling straight, the knob 5
Since there is no opportunity to correct the position of 2a, the position of the knob 52a is deviated from the neutral position even though the steered wheels are in the straight traveling posture. Therefore, the knob 52a may not be able to be used as a guide for determining the turning angle of the steered wheels.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a steering angle correcting device having a function of stopping a steering wheel position correction when a steering wheel operating speed is lower than a set value. An object of the present invention is to provide a steering wheel angle correction device and a vehicle in a power steering device that can prevent the steering wheel position from being shifted due to fine adjustment of the steering wheel during traveling.

[0012]

According to the first aspect of the present invention, there is provided a steering angle detecting means for detecting an actual position of a steering wheel, and a steering angle detecting means for detecting a steering angle of a steering wheel. Switching means for changing the ratio of the change in the steering angle of the steered wheels to the operation amount of the steering wheel smaller than usual, and a shift between the actual position of the steering wheel and a target position corresponding to the steering angle of the steered wheels. Control means for driving and controlling the switching means so that the amount is at least equal to or less than an allowable value; handle operation speed detection means for directly or indirectly detecting the operation speed of the handle; and wherein the handle operation speed is equal to or less than a set value. A correction prohibition unit for prohibiting the control unit from correcting the position of the steering wheel; a steering angle determination unit for determining whether or not the steering angle of the steered wheels is within a straight traveling range; When the steering angle of is in the straight range, the steering speed is even lower than the set value, and a straight region correction executing means for executing positional correction of the steering wheel by the control unit.

According to a second aspect of the present invention, in the steering angle correction device for the power steering device according to the first aspect, a vehicle speed detecting means for detecting a vehicle speed, and whether or not the vehicle speed is lower than a predetermined speed. The correction prohibition means, when the vehicle speed is lower than a predetermined speed, irrespective of whether the turning angle of the steered wheels is within a straight traveling range or not. A low-vehicle-speed-correction prohibiting unit for prohibiting the control unit from correcting the position of the steering wheel when the steering wheel operating speed falls below a set value is provided.

According to a third aspect of the present invention, in the steering wheel angle correcting apparatus according to any one of the first to second aspects, the steering wheel operating speed detecting means includes a steering wheel operating unit for steering the steering wheel per unit time. It is a steering angular velocity detecting means for detecting a steering angular velocity which is an angle change amount.

According to a fourth aspect of the present invention, in the steering wheel angle correction apparatus according to the third aspect, the correction prohibiting means determines a driving state of the switching means, and a driving of the switching means. An operation speed determination unit configured to determine whether a steering wheel operation speed is equal to or less than the set value in consideration of a difference in a steering angle change ratio of the steered wheels with respect to an operation amount of the steering wheel depending on a state. I have.

According to a fifth aspect of the present invention, in the steering wheel angle correcting apparatus according to any one of the first to fourth aspects, the control means includes: the steering angle detected by the steering angle detecting means. A target position calculating means for calculating the target position from the relative angle of the handle from the actual position and the target position detected by the handle angle detecting means at the relative angle of the handle are less than an allowable value of the relative angle. Correct the position of the handle so that it fits.

According to a sixth aspect of the present invention, in the steering wheel angle correcting apparatus according to the fifth aspect, the control means determines a target direction in which the handle needs a shortest path from the actual position to the target position. Target direction detecting means for detecting,
Operation direction detection means for detecting the operation direction of the handle, and correction execution selection means for executing position correction of the handle only when the operation direction of the handle matches the target direction.

According to a seventh aspect of the present invention, a vehicle is provided with the steering wheel angle correcting device according to any one of the first to sixth aspects. (Operation) According to the first aspect of the present invention, the actual position of the steering wheel is detected by the steering wheel angle detecting means, and the steering angle of the steered wheels is detected by the steering angle detecting means. When the allowable value exceeds the deviation between the actual position of the steering wheel and the target position corresponding to the steering angle of the steered wheels, the switching means is driven by the control means. As a result, the ratio of the change in the steering angle of the steered wheels to the operation amount of the steering wheel becomes smaller than usual, and the steering wheel idles, and the position correction of the steering wheel is executed until the deviation amount at least falls below the allowable value. At this time, the operating speed of the steering wheel is detected by the steering wheel operating speed detecting means, and the steering angle determining means determines whether or not the turning angle of the steered wheels is within the straight traveling range. When the handle operation speed falls below the set value, the correction of the handle position by the control means is prohibited by the correction prohibition means. However, when the turning angle of the steered wheels is in the straight traveling range, the straight traveling area correction executing means causes the control means to execute the steering wheel position correction even if the steering wheel operating speed is lower than the set value. Therefore, when the steering wheel is operated to finely adjust the steering angle of the steered wheels during straight traveling, the steering wheel position is corrected even if the steering wheel operating speed is low.

According to the second aspect of the present invention, when the vehicle speed is detected by the vehicle speed detecting means and the vehicle speed determining means determines that the vehicle speed is lower than the predetermined speed,
Regardless of whether the steered angle of the steered wheels is within the straight ahead range,
The correction of the steering wheel position by the control means is prohibited by the low vehicle speed correction prohibition means. Therefore, when the reaction force of the steered wheels is large, at least the switching means is not driven to the state at the time of executing the steering wheel position correction, so that the change in the steering angle of the steered wheels is not excessively small in proportion to the operation amount of the steering wheel. Is done.

According to the third aspect of the present invention, the steering wheel operating speed detecting means is a steering angular speed detecting means for detecting a steering angular speed which is an amount of change in the steering angle of the steered wheels per unit time,
The determination as to whether the steering wheel operating speed is equal to or lower than the set value is performed using the steering angular speed.

According to the present invention, the driving state of the switching means is determined by the first determining means. Considering that the ratio of the change in the steering angle of the steered wheel to the operation amount of the steering wheel is different due to the difference in the driving state of the switching means as a result of the judgment by the first judging means, the operating speed judging means makes the steering wheel operating speed equal to or less than the set value Is determined.
Therefore, it is possible to accurately determine whether the steering wheel operating speed is equal to or less than the set value even from the steering angular speed.

According to the fifth aspect of the present invention, the actual position of the handle is detected by the handle angle detecting means based on the relative angle of the handle, and the target position used for correcting the handle position is determined by the target position calculating means. The angle is obtained from the steering wheel turning angle. The steering wheel position correction is performed such that the deviation amount falls within an allowable value in a relative angle. Since the position correction of the steering wheel is performed based on the deviation amount in the relative angle, even when the steering wheel is deviated by 360 degrees or more with respect to the steered wheels, the correction amount is smaller by one rotation or two rotations and less than 360 degrees.

According to the sixth aspect of the present invention, the target direction in which the shortest path is required for the handle to reach the target position from the actual position is detected by the target direction detecting means. Only when the operation direction of the steering wheel detected by the operation direction detection unit matches the target direction, the position correction of the steering wheel is executed by the correction execution selection unit. Therefore, for example, even if the steering wheel is actually shifted by 280 °, the correction of 80 ° is sufficient, and the idling amount of the steering wheel accompanying the correction of the steering wheel position can be further reduced.

According to the seventh aspect of the present invention, the vehicle is provided with the steering wheel angle correction device according to any one of the first to sixth aspects. The same operation as the invention according to any one of claims to 6 is obtained.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 3 shows a power steering device 1 mounted on a forklift F as a vehicle. A steering wheel (steering wheel) 2 that is rotated by an operator is provided with a knob 2a for improving the operability. The steering shaft 3 supporting the handle 2 is an orbit roll 4
It is connected to.

A valve unit 5 constituting the orbit roll 4 has a supply pipe 7 through which hydraulic oil from a hydraulic pump (loading pump) 6 driven by an engine (not shown) is supplied, and a drain tank 8. A discharge pipe 9 for discharging oil is connected. A relief valve 11 is interposed in a conduit 10 connecting the supply pipe 7 and the discharge pipe 9, and the relief valve 11 keeps a hydraulic pressure fed from the hydraulic pump 6 to the valve unit 5 at a constant pressure (set pressure). It has become so.

The valve unit 5 is driven directly by the steering shaft 3, and supplies an oil amount proportional to the rotation amount of the handle 2 to a steering cylinder 12 described later.
It has the function of supplying to Valve unit 5
And the steering cylinder 12 have two hydraulic lines 13,
14 are connected. When the handle 2 is turned to the right, the hydraulic line 13 functions as a supply line for supplying hydraulic oil from the hydraulic pump 6, and the hydraulic line 14 functions as a return line for returning hydraulic oil to the hydraulic pump 6. When the handlebar 2 is turned to the left, the hydraulic line 14 functions as a feed line, and the hydraulic line 13 functions as a return line.

The steering cylinder 12 has a hollow cylindrical cylinder tube 15 fixed to a vehicle body, a piston 16 reciprocally disposed inside the cylinder tube 15, and a pair of left and right pistons extending from both ends of the cylinder tube 15. Rods 17a and 17b are provided. Each hydraulic line 1
Each of the cylinders 3 and 14 is communicated with each chamber of a cylinder tube 15 divided into two chambers by a piston 16.

Left and right steered wheels (rear wheels) 19, 19 are connected to the distal ends of the piston rods 17a, 17b via link mechanisms 18a, 18b. The wheels 19 are steered left and right about the kingpin 20.

The hydraulic lines 13 and 14 are connected by a bypass line 21, and an electromagnetic switching valve 22 and a throttle valve 23 as switching means are provided in the bypass line 21. The electromagnetic switching valve 22 is for returning a part of the oil amount discharged from the valve unit 5 to the drain tank 8 via the bypass line 21. By opening the electromagnetic switching valve 22 to recirculate a part of the oil amount,
Steering cylinder 12 with respect to operation amount of handle 2
In this case, the idling state of the steering wheel 2 is created by reducing the ratio of the displacement amount of the piston 16 in FIG. The position of the steering wheel 2 is corrected by causing the steering wheel angle to catch up with the steering angle (steering angle) of the steered wheels 19 by idling of the steering wheel 2.

The electromagnetic switching valve 22 is a two-position switching valve,
Shut-off position where the bypass line 21 is cut off (state in FIG. 3)
And a communication position at which the bypass line 21 is communicated. A spool (not shown) constituting the electromagnetic switching valve 22 is urged toward a shut-off position by a spring 24. The electromagnetic switching valve 22 is disposed at a communication position when the solenoid 25 is excited, and the solenoid 25 is demagnetized. When it is done, it will be placed in the blocking position. The solenoid 25 is electrically connected to the controller 26, and is controlled to excite and demagnetize based on a control signal from the controller 26. The throttle valve 23 is provided so that the steering line 19 can be steered by the steering wheel operation even if the electromagnetic switching valve 22 remains open due to a failure or the like.
1 is for reducing the flow rate.

The controller 26 includes a potentiometer 27 as a steering angle detecting means and a steering operation speed detecting means and a potentiometer 28 as a steering angle detecting means and a steering angle detecting means. Connected. The potentiometer 27 is provided such that rotation of the steering shaft 3 is input to an input shaft of the steering shaft 3 via a gear train 29 disposed on the steering shaft 3. The gear ratio of the gear train 29 is set to “1.0”, and a handle angle signal θ corresponding to the relative angle of the handle 2 is input from the potentiometer 27 to the controller 26.

The potentiometer 28 is disposed on a kingpin 20 that supports the right steering wheel 19, and detects the amount of rotation of the kingpin 20 to detect the steering wheel 19.
Is detected, and a titer angle signal R corresponding to the angle is input to the controller 26.

The potentiometer 27 has a handle angle θ for setting the position of the knob 2a to “0 °” when the handle 2 is in the neutral position (a normal handle position when the steering angle is 0 °).
Is set to detect the current position of the knob 2a. Generally, a potentiometer has one of its input shafts.
A non-detection area where position detection is impossible is always formed in the rotation area (in this embodiment, a detection area of 300 ° is used, for example), but the steering wheel angle “0 °” is detected at the center of the detection area. The interruption of the knob position correction near the neutral position of the handle 2 is prevented as much as possible.

The controller 26 includes a vehicle speed sensor 3
0 is electrically connected. The vehicle speed sensor 30 is provided on a front differential ring gear (not shown) for transmitting a rotational force to driving wheels (not shown), and outputs a vehicle speed signal v proportional to the vehicle speed.

The controller 26 comprises a steering wheel operating speed detecting means, a steering angular speed detecting means, a control means, a target position calculating means and an operating direction detecting means, as well as a steering angle determining means, a straight running area correction executing means, a correction inhibiting means, a vehicle speed. A central processing unit (CPU) 31 as a determining means, a low vehicle speed correction inhibiting means, an operation speed determining means, a first determining means, a target direction detecting means and a correction execution selecting means, and a read-only memory (ROM) constituting a target position calculating means ) 32, a read / write rewritable memory (RAM) 33, a clock circuit 34, a counter 3 constituting operation direction detecting means and steering angular velocity detecting means
5, an AD conversion circuit 36, 37, 38 and an excitation / demagnetization drive circuit 39 constituting a control means. The signals θ and R from the potentiometers 27 and 28 are converted to AD conversion circuits 36 and
37 as an 8-bit AD value (0 to 255)
Input to the PU 31 and the CPU 31
The values are taken as the steering wheel angle θ and the tire turning angle R.

Various kinds of program data to be executed by the CPU 31 are stored in the ROM 32. One of them is program data for the knob position correction control processing shown in the flowcharts of FIGS. In this flowchart, step S30 is a steering wheel speed detecting unit and a steering angular speed detecting unit, S40 is a first determining unit, and S40 to S
Reference numerals 90 and S220 denote correction inhibiting means, S50 and S60 denote operation speed determining means, S70, S80 and 200 denote straight ahead area correction executing means, S80 denotes vehicle speed determining means, S80 and S90 denote low vehicle speed correction inhibiting means, and S110 denotes target position calculation. Means, S70
Is steering angle determination means, S130 is operation direction detection means, S15
0 constitutes the target direction detecting means, and S190 to S210 constitute the correction execution selecting means.

The ROM 32 stores a map M shown in FIG.
1 is stored. The map M1 is for obtaining a target steering wheel angle θg, which is a target position for correcting the position of the knob 2a, from the tire turning angle R. The tire turning angle “0 °” is associated with the AD value “128”. When the value of the tire turning angle R is “negative”, the left turning angle (left steering) is set, and when the value is “positive”, the right turning angle is set. (Right steering). Further, the relative angle “0 °” of the target handle angle θg is associated with the AD value = 128, and the left and right sides of the neutral position (= 0 °), which is the detection area of the handle angle θ, are each “−1”.
The target handle angle θg is set in the range of “50 ° to 150 °”. The map M1 includes, in the entire steering angle range between the left and right stroke ends RE and LE of the tire turning angle R,
A control target line L that associates the tire turning angle R with the target steering wheel angle θg is set.

This control target line L is an ideal control line on the assumption that the orbit roll efficiency (actual discharge amount / theoretical discharge amount) is 100%. In a portion corresponding to the non-detection region of the tire turning angle R, the target steering wheel angle θg is set as AD value = 0, that is, −150 °. When one of the steering wheel angle θ and the tire turning angle R is in the non-detection region, the knob position correction is not executed. Since the potentiometer 28 uses only the detectable region for detecting the tire turning angle, the tire turning angle is detected in the entire steering angle range.

The calculation result of the CPU 31 and the like are temporarily stored in the RAM 33. Further, the CPU 31 includes a clock circuit 34.
The predetermined time to (for example, 10
The knob position correction control processing shown in FIGS. 1 and 2 is executed at intervals of (milliseconds), and the steering wheel angle θ and the tire turning angle R are set in the counter 35 each time the processing is executed. The counter 35 stores data of the steering wheel angle θ and the tire turning angle R for a plurality of past times. Further, a control signal for exciting / demagnetizing the solenoid 25 is supplied to the CPU 31 via an exciting / demagnetizing drive circuit 39.
Is output from

In the knob position correction control processing, the CPU 31 calculates a deviation Δθ between the steering wheel angle θ and the target steering wheel angle θg obtained from the tire turning angle R, and this deviation Δθ is set to an allowable value θo (for example, about 5 °). ) Perform the knob position correction so that it falls within the following. Here, the deviation amount Δθ means a deviation amount that passes through the shortest path between the current knob position and the target knob position as shown in FIG. 5, and the actual deviation amount Δθs of the knob 2a is 1
When it exceeds 80 °, the deviation amount Δθ becomes “360 ° −Δ
θs ”.

As shown in FIG. 5, the condition for executing the knob position correction differs depending on whether or not the shift amount Δθ is equal to or smaller than a predetermined angle A °. That is, when the deviation amount Δθ is equal to or smaller than A ° (that is, when the actual deviation amount Δθs satisfies Δθs ≦ A ° or Δθs ≧ (360−A) °), the shortest path from the current knob position to the target knob position is obtained. The knob position correction is executed only when the operation direction of the handle 2 coincides with the direction (hereinafter, referred to as the target direction). When the shift amount Δθ exceeds the predetermined angle A ° (that is, when the actual shift amount Δθs satisfies A ° <Δθs <(360−A) °), the knob position correction is performed regardless of the handle operation direction. It is always executed.

Here, when the deviation is larger than the predetermined value, the predetermined value A is larger than the expansion of the deviation even if the correction is executed when the steering wheel 2 is operated in the direction opposite to the target direction. Rather, it is a boundary value at which the probability of contraction increases. The range in which the primary effect of the predetermined value A ° is expected is 40 °
~ 180 °, the preferred range is 60 ° ~ 160
°, the optimal range is 80 ° to 120 °. If the predetermined value A is less than 60 °, there is a concern that the probability of increasing the amount of deviation increases, and if it exceeds 160 °, it is difficult to expect that the frequency of execution of the correction will increase too much. In the range of 80 ° to 120 °, it is possible to effectively increase the frequency of executing the correction while avoiding an increase in the shift amount.

FIG. 6A is a graph showing the relationship between the handle rotation speed and the orbit roll efficiency. When the handle rotation speed (rps) is low, even if the handle 2 is rotated once, only a flow rate smaller than the rated Q (cc / rev) is discharged. It decreases as the speed decreases. FIG. 6B is a graph showing the ratio (correction ratio) of the amount of oil that is bypassed by opening the electromagnetic switching valve 22 out of the amount of oil discharged from the valve unit 5. The tire reaction force (steering resistance) is regarded as constant. The correction ratio (%) increases as the steering wheel rotation speed decreases, and when the steering wheel rotation speed is lower than Vo, the correction ratio becomes 100% and all of the discharge oil amount is bypassed. This means that the steering angle change stops completely.

In the present embodiment, the steering wheel operating speed is set to a predetermined speed Vmin (this embodiment) in order to prevent a deterioration in the steering wheel operation feeling that the steering angle of the steered wheels 19 does not change despite the steering wheel operation. Then, "0.3
rps "), the knob position correction is prohibited. In the present embodiment, the steering angular velocity of the steered wheels 19 is used to determine whether the steering wheel operating speed is lower than the predetermined speed Vmin. Tire turning angle R before the specified time n · to
(Hereinafter referred to as “R1”) and the deviation ΔR (= | R−R1 |) from the current tire turning angle R is regarded as the steering angular velocity.

Here, the relationship between the steering angular speed and the steering wheel operating speed is different between when the electromagnetic switching valve 22 is opened and when it is closed, so that the steering wheel operating speed becomes the predetermined speed Vmin (0.3 rpm).
s) Two kinds of judgment values r for judging that it is less than
1, r2 are prepared. That is, when the condition of ΔR <r1 is satisfied when the electromagnetic switching valve 22 is closed, and when the condition of ΔR <r2 is satisfied when the electromagnetic switching valve 22 is opened, it is determined that the steering wheel operating speed is lower than the predetermined speed Vmin. Judgment value r
1, r2 indicates that the steering wheel 2 has a predetermined speed Vmin (= 0.3r
This is a value in consideration of the orbit roll efficiency and the correction ratio when operated at (ps).

In the present embodiment, in the straight traveling range in which the steering wheel 2 is operated during straight traveling (in this embodiment, a range of ± 110 ° from the neutral position of the steering wheel 2), the steering wheel operating speed is equal to the predetermined speed Vmin (0). .3 rps), the knob position correction is executed. Whether or not the vehicle is in the straight traveling range is determined from the tire turning angle R.

When traveling is stopped (or when traveling at low speed)
In order to prevent the correction ratio from becoming too large by opening the electromagnetic switching valve 22 in such a case, the tire turning angle R is limited to a linear range when the vehicle speed is 5 km / h or less. If the handle operation speed is lower than the predetermined speed Vmin (0.3 rps), the knob position correction is prohibited. Note that the predetermined speed V
min (0.3 rps) is a value slightly larger than the predetermined value Vo in the graph of FIG. 6B.

Next, the operation of the power steering device 1 will be described. When operating the forklift F,
The operator operates the handle 2 while holding the knob 2a.
When the handle 2 is operated and the steering shaft 3 is driven to rotate, the hydraulic oil discharged from the valve unit 5 according to the amount of operation of the handle 2 causes the steering cylinder 1
The steering wheel 19 is steered to a steering angle corresponding to the operating position of the steering wheel 2. The knob 2a may deviate from the normal position due to a decrease in the orbit roll efficiency when the handle operation speed is low, an oil leak in the hydraulic system such as the steering cylinder 12, or the like. for that reason,
Knob position correction control for correcting the position of the knob 2a to a proper position corresponding to the tire turning angle is performed.

The knob position correction control executed by the CPU 31 will be described below with reference to the flowcharts shown in FIGS. In this knob position correction control, it is determined whether the control of the electromagnetic switching valve 22 is to be opened or closed in the processing of S10 to S210, and in the last step 220, the control of the electromagnetic switching valve 22 based on the determination result is performed. Open / close control is performed. Whether the electromagnetic switching valve 22 is in the open state or the closed state is recognized by the CPU 31 by looking at the valve flag set to “0” in the closed state and “1” in the open state. It has become. Various flags other than the valve flag are reset prior to the execution of the process.

While the engine of the forklift F is being driven, CP
U31 includes a handle angle signal θ corresponding to the relative angle of the knob 2a from the potentiometer 27, and a potentiometer 28.
, A tire turning angle signal R corresponding to the turning angle of the steered wheels 19 and a vehicle speed signal v from the vehicle speed sensor 30 are inputted through the respective AD conversion circuits 36 to 38.

First, in step 10, the CPU 31 reads the steering wheel angle θ and the tire turning angle R. In the next step 20, the tire turning angle R1 before the predetermined time n · to
Is read from the counter 35. In step 30, the deviation ΔR = | R−R1 | is calculated. This deviation ΔR is a value proportional to the steering angular velocity.

In step 40, it is determined whether or not the electromagnetic switching valve 22 is in a valve open (open) state. That is, if the valve flag is "0", it is determined that the valve is closed (valve closed), and if it is "1", it is determined that the valve is open. If the valve is in the closed state, proceed to step 50,
If the valve is in the open state, the process proceeds to step S60.

In steps 50 and 60, it is determined whether or not the handle operation speed is lower than a predetermined speed Vmin (0.3 rps). That is, in step 50, it is determined whether or not ΔR <r1 holds, and ΔR <r1
Is established, the steering wheel operating speed becomes the predetermined speed Vmin (0.
It is determined that it is less than 3 rps), and the routine proceeds to step 70. If ΔR <r1 is not satisfied, the routine proceeds to step 100 on the assumption that the handle operation speed is equal to or higher than the predetermined speed Vmin. On the other hand, in step 60, it is determined whether or not ΔR <r2 is satisfied. When ΔR <r2 is satisfied, it is determined that the steering wheel operating speed is lower than the predetermined speed Vmin, and step 7 is performed.
0, and when ΔR <r2 is not established, step 100
Move to

Here, the judgment value r1 is that the steering wheel operating speed Vmin (0.3 rps) is converted into a steering angular speed corresponding to the orbit roll efficiency (for example, 70%) at this speed Vmin when the valve is closed. Is set in consideration of Further, the determination value r2 is set in consideration of the fact that the steering wheel operating speed Vmin (0.3 rps) is converted into a steering angular speed corresponding to the correction ratio (for example, 80%) at this speed Vmin when the valve is open. Value. Therefore, it is determined that ΔR <r1 holds when the valve is closed, and ΔR <r1 when the valve is open.
By determining the establishment of r2, it is possible to accurately determine whether the steering wheel operating speed is lower than the predetermined speed Vmin (0.3 rps) even from the steering angular speed ΔR.

In step 70, it is determined whether or not the tire turning angle R is within the straight traveling range. If the tire turning angle R is within the straight traveling range, the routine proceeds to step 80. On the other hand, if the tire turning angle R is not within the straight traveling range, the routine proceeds to step 90, where a valve close determination is made, and the determination flag is set to "1". For this reason, the steering operation speed is reduced to a predetermined speed Vmin.
Even if the steering angle is less than (0.3 rps), when the steering angle of the steered wheels 19 is out of the straight traveling range (that is, when the steering wheel 2 is largely turned out of the straight traveling range), the knob position correction is not performed. Will be executed.

In step 80, the vehicle speed is "5 km / h".
It is determined whether or not: If the vehicle speed is 5 km / h or less, the routine proceeds to step 90, where a valve close determination is made, and the determination flag is set to "1". Therefore, even if the steering wheel operating speed is lower than the predetermined speed Vmin (0.3 rps) and the turning angle of the steered wheels 19 is within the straight traveling range, the knob position correction is not executed when the vehicle speed is 5 km / h or less. Become. On the other hand, if the vehicle speed exceeds 5 km / h,
Proceed to step 100.

In step 100, it is determined whether or not the valve closing has been determined. When the valve close determination has been made (the determination flag is “1”), the process proceeds to step 220, and a valve drive command is executed based on the determination result.
That is, a demagnetization signal is output to the solenoid 25 to drive the electromagnetic switching valve 22 to close. On the other hand, if the valve close determination has not been made (the determination flag is “0”), step 1
Go to 10.

In the next step 110, the target steering wheel angle θg corresponding to the current tire turning angle R is calculated using the map M1 shown in FIG. In step 120, it is determined whether or not one of the steering wheel angle θ and the target steering wheel angle θg corresponds to an undetected value. If the θg value is “−150 °” or the AD value of the steering wheel angle θ is “0”, it is determined that detection is not performed. If not, step 2
The process proceeds to 10, where a valve close determination is made, and the determination flag is set to "1". Therefore, if either the θ value or the θg value is out of the detection, the electromagnetic switching valve 22 is closed and the knob position correction is not performed. When both the θ value and the θg value are in the detection area, the process proceeds to the next step 130.

In step 130, the steering direction of the steering wheel 2 is calculated. That is, the steering wheel angle θ1 before the predetermined time n · to is read out from the counter 35, and the steering wheel angle θ1
And the current steering angle θ, and | θ−θ1 | ≧
It is determined whether or not θB is established, and the steering direction of the steering wheel 2 is determined based on the two determination results. Here, the θB value is a predetermined value (for example, 50 ° or more) which is equal to or greater than a limit value at which the steering wheel 2 cannot be physically operated within a predetermined time n · to.
When the operation amount of the steering wheel 2 (= | θ−θ1 |) is equal to or larger than the physically impossible θB value, the steering operation is performed so as to pass through the non-detection region of the steering wheel angle θ. (That is, when the AD value switches between “0” and “255”), the operation direction of the steering wheel 2 is determined.

That is, when the value of the steering wheel angle θ increases during the predetermined time n · to (θ> θ1), the steering direction is “rightward” unless | θ−θ1 | ≧ θB is satisfied.
If | θ−θ1 | ≧ θB holds, it is determined to be “leftward”. When the value of the steering wheel angle θ decreases during the predetermined time n · to (θ <θ1), the steering direction is | θ−
Unless θ1 | ≧ θB holds, “leftward”, | θ−θ1
If | ≧ θB holds, it is determined to be “rightward”. As a result of this determination, the steering flag is set to "0" for "left direction" and "1" for "right direction". When θ = θ1, a determination is made as to whether the steering wheel operation has stopped, and the stop determination flag is set to “1”.

At step 140, it is determined whether or not the steering operation is stopped. If "1" is set in the stop determination flag, the process proceeds to step 210, where a valve close determination is made, and the determination flag is set to "1". Therefore, the knob position correction is not performed while the steering operation is stopped.

In the next step 150, a target direction in which the knob deviation correction is executed is calculated. That is, a comparison is made between the current handle angle θ and the target handle angle θg, and it is determined which of the left and right directions is the shortest path from the current knob position to the target knob position. The deviation | θ−θg | is 1
When the angle is equal to or less than 80 °, the target direction is determined to be “rightward” when θ <θg is satisfied, and the target direction is determined to be “leftward” when θ> θg is satisfied. If the deviation | θ−θg | exceeds 180 °, it is determined that the target direction is “leftward” when θ <θg holds, and that the target direction is “rightward” when θ> θg holds.

In step 160, the amount of deviation Δθ between the current knob position and the target knob position is calculated. Deviation | θ−θg |
Is equal to or less than 180 °, Δθ = | θ−θg |, and if the deviation | θ−θg |
θ = 360 ° − | θ−θg |. Thus, the shift amount Δθ between the current knob position and the target knob position in the shortest path is obtained.

In the next step 170, it is determined whether or not the deviation amount Δθ is equal to or smaller than the allowable value θo. If the deviation amount Δθ is equal to or smaller than the allowable value θo, the process proceeds to step 210 to determine whether the valve is closed. Therefore, the deviation amount Δθ becomes the allowable value θ
o If below, knob position correction is not executed. On the other hand, when the deviation amount Δθ exceeds the allowable value θo, step 180
Move to In step 180, it is determined whether the deviation amount Δθ is equal to or smaller than a predetermined value A °. If Δθ> A °, the routine proceeds to step 200, in which a valve open determination is made and the determination flag is set to “0”. Therefore, when the knob 2a is located at the dashed line position in FIG. 5 (the deviation amount Δθ exceeds the predetermined value A °), even if the operation direction of the handle 2 is the left direction (c direction), the operation direction is the right direction (d direction). Even so,
Unless the valve is closed, the knob position is corrected whenever the steering wheel is operated. Handle operation is d
Direction, the correction is performed on the longest path, but the deviation amount Δ
In the region where θ exceeds the predetermined value A °, there is a high probability that the position of the knob 2a is reduced rather than enlarged, so the chances of performing the knob position correction increase, and the position of the knob 2a is left with the deviation exceeding A °. Is avoided as much as possible.

On the other hand, when Δθ ≦ A ° is satisfied, step 1
The process proceeds to 90, and it is determined whether the steering direction matches the target direction. When the steering direction matches the target direction, the process proceeds to step 200 to perform a valve open determination,
If the steering direction does not match the target direction, step 2
The process proceeds to 10, where a valve close determination is made.

Therefore, when the knob 2a is located at the solid line position in FIG. 5, the knob position correction is executed only when the knob 2a is operated in the direction a approaching the target knob position by the shortest path. When the steering wheel is operated in the direction b away from the target knob position (that is, approaching on the longest route), the knob position correction is not executed. Even if the knob 2a deviates from the normal position by (360-A) ° or more, the knob position correction is executed only when the handle 2 is operated in a direction to approach the target knob position via the shortest path. . Note that no matter how much the actual knob position deviates from the normal position corresponding to the tire turning angle by 360 ° or more, the correction based on the relative angle involves only the apparent deviation amount up to the target knob position. Is always 360
Less than °.

In step 220, a valve drive command is issued based on the valve determination result (determination flag) made in the processing from S10 to S220. When the determination flag is “1”, a demagnetizing signal is output to the solenoid 25 to drive the electromagnetic switching valve 22 to close, and when the determination flag is “0”, the solenoid 2
5 to drive the electromagnetic switching valve 22 to open. In this way, the electromagnetic switching valve 22 is controlled to open and close every predetermined time to. When the values of θ and θg are out of the detection range, the knob position correction is interrupted. However, since this correction is interrupted temporarily while passing through the non-detection region, there is not much problem.

As described in detail above, according to the present embodiment,
The following effects can be obtained. (A) When the tire turning angle R is in the straight running range, the knob position correction is executed even when the steering wheel operating speed is lower than the predetermined speed Vmin (0.3 rps). The problem that the knob position is gradually shifted by operating the handle for fine adjustment of the angle can be solved.

(B) Even when the tire turning angle is within the straight running range when the steering wheel operation is slow, the knob position correction is prohibited if the vehicle speed is as low as 5 km / h or less. It is possible to prevent the feeling of steering operation from deteriorating due to the valve opening when the tire reaction force is large, such as when stopping.

(C) Since the position of the knob 2a is prevented from being gradually shifted by operating the steering wheel while traveling straight ahead,
Since the deviation amount Δθ has exceeded the predetermined value A ° during the straight running, when the steering wheel 2 is turned in the direction of the deviation thereafter, the knob position correction is executed, and the steering wheel 2 is moved to (360−
A) The idling situation can be almost eliminated.

(D) The steering operation speed is determined from the steering angular speed (deviation ΔR), and two types of determination values r1 and r2 are selectively used depending on whether the valve is open. It is possible to accurately determine whether the steering wheel operating speed is low even from ΔR).

(E) The judgment values r1 and r2 are the predetermined speed Vmin
Is set in consideration of the orbit roll efficiency in the above, it is possible to more accurately determine whether or not the handle operation speed is low.

(F) Since the target steering wheel angle θg is determined based on the tire turning angle, the target steering wheel angle θg can be set by the relative angle of the steering wheel.
Knob position correction for adjusting the relative angle of the handle can be realized. Therefore, even if the actual shift amount is equal to or more than 360 °, the correction amount can be reduced by, for example, one rotation or two rotations.

(G) When the deviation Δθ is equal to or smaller than A °, the correction is executed only when the steering wheel 2 is operated in the target direction passing through the shortest path. Even if there is, a correction amount of about 80 ° can be completed. In addition, it is possible to avoid increasing the correction amount as much as possible.

The present invention is not limited to the above embodiment, but can be embodied as follows without departing from the spirit of the invention. (1) The determination as to whether or not the handle operation speed is equal to or less than the set value may be made based on the handle rotation speed obtained by using the handle angle θ data from the potentiometer 27. FIG. 7 shows S20 to S20 in FIG. 1 so that the steering wheel operating speed can be determined from the steering wheel angle θ.
The processing up to S60 is replaced with the processing of S310 to S330. The steering angle θ is stored a plurality of times in the past, and in S310, the steering angle θ1 before the predetermined time n · to is read. In S320, the predetermined time n
Calculate a deviation Δθ (= | θ−θ1 |) between the previous steering wheel angle θ1 and the current steering wheel angle θ. In S330,
It is determined whether the deviation Δθ is less than the determination value d (that is, the handle operation speed is less than “0.3 rps”). According to this configuration, the detection accuracy of the handle operation speed can be increased.

(2) The steering operation speed may be detected by using a differentiating circuit. In this case, the steering angle signal may be obtained by inputting the tire turning angle signal R to the differentiating circuit, or the steering wheel rotational speed may be obtained by inputting the steering angle signal θ to the differentiating circuit.

(3) The steering wheel operating speed may be obtained by detecting the discharge flow rate from the valve unit 5.
According to this configuration, the discharge flow rate from the valve unit is substantially proportional to the steering wheel rotation speed, so that it is not necessary to consider the switching state of the electromagnetic switching valve 22 as in the determination using the steering angular speed.

(4) Instead of using the two determination values r1 and r2 to determine whether the steering operation speed using the steering angular velocity ΔR is equal to or less than the set value, a correction coefficient is applied to the deviation ΔR when the valve is open. A method may be used in which correction such as multiplication is performed, and a determination is made using one common determination value when the valve is closed and when the valve is open. With this configuration,
It is possible to accurately determine whether the steering wheel operating speed is equal to or less than the set value from the steering angular speed.

(5) A reduction gear having a worm gear or the like is provided between the steering shaft 3 and the potentiometer 27, and the detected value of the absolute angle detected by the potentiometer 27 is converted into a relative angle by calculation or the like, and the tire turning angle is calculated. The actual steering wheel angle θ may be corrected to the target steering wheel angle θg of the relative angle obtained from R. In this case, a calculating means for converting the absolute angle into a relative angle (for example, means for performing a calculation process or a map calculation) constitutes a steering wheel angle detecting means. According to this configuration, although a calculation means for obtaining the relative angle θ from the absolute angle is required, a non-detection region of the steering wheel angle θ can be eliminated.

(6) In the present invention, the low speed equal to or lower than the predetermined speed refers to a speed range in which the tire reaction force acting on the steering cylinder 12 is large (for example, a walking speed (several km / km).
h)) or a speed equal to or lower than a predetermined speed with a certain allowance so that the steering wheel position correction is executed reliably in that speed range. For example, given a margin, set the predetermined speed to 10 km.
/ H.

(7) In the above embodiment, the limitation on the vehicle speed, which is one of the conditions for prohibiting correction, may be removed. That is, even when the vehicle speed is lower than the predetermined speed, the steering wheel position correction may be performed when the steering angle is in the straight traveling range.
According to this configuration, the steering angle change is smaller than the steering wheel operation due to the tire reaction force during low-speed running, but the knob 2a can be prevented from being displaced during the fine adjustment of the steering wheel 2 during straight running.

(8) The ratio of the tire turning angle R to the target steering wheel angle θg of the control target line L may be set to be smaller than the ideal line having an orbit roll efficiency of 100%. According to this configuration, since the execution frequency of the knob position correction in the straight traveling range increases, the convergence of the knob 2a to the neutral position can be improved.

(9) The present invention may be implemented for the purpose of correcting the position of a handle without a knob. By applying the present invention to a handle without a knob, it is possible to avoid the displacement of the handle during straight running as much as possible.

(10) The present invention may be applied to a conventional device for detecting a steering wheel angle as an absolute angle as described in the prior art. (11) In a configuration in which the steering wheel angle is detected as an absolute angle as in the conventional device, it may be determined from the steering wheel angle whether or not the steering angle of the steered wheels is within the straight traveling range. In this case, an accurate determination result can be obtained by taking into account the amount of displacement of the steering wheel.

(12) In the above embodiment, the present invention is applied to a forklift, but the present invention can be widely applied to industrial vehicles other than a forklift having a power steering device, and also to vehicles such as automobiles (passenger cars).

The invention which has been grasped from the above embodiment and which is not described in the claims will be described below together with its effects. (A) In the invention according to any one of claims 1 to 7, the steered wheels are steered by a hydraulic actuator that is operated based on hydraulic oil discharged in accordance with an operation amount of the steering wheel. The switching means is a switching valve provided on a recirculation passage for recirculating a part of the hydraulic oil discharged to the actuator to a drain tank. Also with this configuration, it is possible to prevent the handle position from being shifted due to fine adjustment of the handle during straight running.

(B) Claims 1 to 7 and (A)
In the invention according to any one of the above, a knob is provided on the handle, and the control means drives and controls the switching means so that the knob is arranged at a regular position. According to this configuration, the position of the knob can be corrected to a regular position corresponding to the turning angle of the steered wheel, and the position of the knob can be used as a guide for determining the turning angle of the steered wheel.

(C) In the invention according to claim 6, a second judging means (corresponding to S180) for judging whether or not the deviation amount of the shortest path between the actual position and the target position is larger than a predetermined value. Correction execution means for driving the switching means irrespective of the direction of operation of the steering wheel when the deviation exceeds a predetermined value, wherein the correction execution selecting means is provided only when the deviation is equal to or less than a predetermined value. The driving of the switching means is performed when the operation direction matches the target direction. According to this configuration,
When the deviation amount in the shortest path exceeds a predetermined value, the steering wheel position correction is executed regardless of whether the operation direction of the steering wheel is left or right, and it is possible to increase the opportunity of the steering wheel position correction while avoiding the deviation amount as much as possible. it can.

(D) In the invention described in claim 7, the vehicle is an industrial vehicle. According to this configuration, the same effect as that of the invention described in claim 7 can be obtained in an industrial vehicle.

[0091]

As described in detail above, claims 1 and 3 have been described.
According to the present invention, even when the steering wheel operating speed is equal to or lower than the set value, the steering wheel position correction is not prohibited when the steering angle of the steered wheels is within the straight traveling range. It is possible to prevent the position of the handle from gradually shifting when the handle is being finely adjusted.

According to the second and seventh aspects of the present invention, when the vehicle speed is lower than the predetermined speed, regardless of whether the turning angle of the steered wheels is within the straight traveling range, the steering wheel position correction is performed. Since at least the switching means is not driven to the state at the time of executing the steering wheel position correction at the time of stop when the reaction force of the steering wheel is large, the steering angle of the steering wheel is excessively changed by the steering amount of the steering wheel. It is possible to avoid being reduced.

According to the fourth and seventh aspects of the present invention, it is considered that the ratio of the change in the steering angle of the steered wheels to the operation amount of the steering wheel is different due to the difference in the driving state of the switching means. Is determined to be less than or equal to the set value, it is possible to accurately determine whether the steering wheel operating speed is less than or equal to the set value even from the steering angular velocity.

According to the fifth and seventh aspects of the present invention, the actual position of the steering wheel is corrected to the target position obtained from the steering angle of the steering wheel based on the relative angle of the steering wheel. On the other hand, when the steering wheel is displaced by 360 degrees or more, a correction amount of less than 360 degrees, which is smaller by one rotation or two rotations, is sufficient, and idling of the steering wheel required for steering wheel position correction can be relatively reduced.

According to the sixth and seventh aspects of the present invention, the steering wheel position is corrected only when the steering wheel is operated in the target direction, which requires the shortest path from the actual position to the target position. With this configuration, even when the deviation of the steering wheel is less than 360 °, the correction amount is smaller than the actual deviation amount, and the idling of the steering wheel accompanying the position correction of the steering wheel can be further reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart of a knob position correction control process according to an embodiment.

FIG. 2 is a flowchart similarly.

FIG. 3 is a schematic diagram of a power steering device.

FIG. 4 is a graph showing a map.

FIG. 5 is an explanatory diagram of knob position correction control.

6A is a graph showing a relationship between a steering wheel rotation speed and an orbit roll efficiency, and FIG. 6B is a graph showing a bypass characteristic at the time of executing correction.

FIG. 7 is a flowchart of another example.

FIG. 8 is a schematic view of a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Power steering device, 2 ... Steering wheel, 19 ... Steering wheel, 22 ... Electromagnetic switching valve as switching means, 27 ... Potentiometer as operating direction detecting means and steering wheel angle detecting means, 28 ... Steering wheel operating speed detecting means And a potentiometer as steering angle detecting means, 31... Steering wheel operating speed detecting means, steering angular speed detecting means, control means, target position calculating means, operating direction detecting means, and steering angle determining means. CPU as a straight traveling area correction executing means, correction prohibiting means, vehicle speed determining means, low vehicle speed correction prohibiting means, operation speed determining means, first determining means, target direction detecting means and correction execution selecting means, 32 target position calculating means ROM that constitutes
35: a counter constituting the operation direction detecting means and the steering angular velocity detecting means; 39, an excitation / demagnetizing drive circuit constituting the control means; F: a forklift as a vehicle.

Claims (7)

[Claims] 1. A steering angle detecting means for detecting an actual position of a steering wheel, a steering angle detecting means for detecting a steering angle of a steering wheel, and a ratio of a change in the steering angle of the steering wheel to an operation amount of the steering wheel in a normal state. Switching means for changing the position of the steering wheel to a smaller value, and control means for controlling the driving of the switching means so that a deviation amount between an actual position of the steering wheel and a target position corresponding to the steering angle of the steered wheel is at least equal to or less than an allowable value. A steering wheel operating speed detecting unit that directly or indirectly detects the operating speed of the steering wheel, a correction inhibiting unit that inhibits the steering unit from correcting the steering wheel position when the steering wheel operating speed is equal to or less than a set value, Steering angle determining means for determining whether or not the steering angle of the steered wheels is in a straight ahead range; and Even value or less, the steering wheel angle correction device according to which the power steering device and a straight region correction executing means for executing positional correction of the steering wheel by the control unit. 2. A vehicle speed detecting means for detecting a vehicle speed, and a vehicle speed judging means for judging whether or not the vehicle speed is lower than a predetermined speed. When the steering speed is lower than the set value, the correction of the steering wheel position by the control means is prohibited when the steering wheel operating speed is equal to or less than a set value, regardless of whether the steering angle of the steered wheels is within the straight traveling range. The steering angle correction device for a power steering device according to claim 1, further comprising a low vehicle speed correction prohibition unit. 3. The steering wheel operating speed detecting unit is a steering angular speed detecting unit that detects a steering angular speed which is a steering angle change amount per unit time of the steered wheels.
A steering angle correction device in the power steering device according to any one of the above. 4. The method according to claim 1, wherein the correction prohibiting unit is configured to determine a driving state of the switching unit and to determine a change in the driving state of the switching unit. The steering angle correction device for a power steering device according to claim 3, further comprising an operation speed determination unit that determines whether the steering wheel operation speed is equal to or less than the set value in consideration of the difference in the ratio. 5. The control means includes target position calculating means for obtaining the target position from the steering angle detected by the steering angle detecting means as a relative angle of a steering wheel, wherein the steering wheel angle detecting means determines a relative angle of the steering wheel. The power steering apparatus according to any one of claims 1 to 4, wherein the position of the steering wheel is corrected so that a deviation amount between the actual position and the target position detected in step (b) falls within an allowable value in a relative angle. Handle angle correction device. 6. The control means includes: a target direction detection means for detecting a target direction in which the handle needs a shortest path from the actual position to the target position; and an operation direction detection for detecting an operation direction of the handle. 6. A steering wheel angle correcting apparatus in a power steering apparatus according to claim 5, further comprising: means for correcting the position of the steering wheel only when the operation direction of the steering wheel matches the target direction. . 7. A vehicle comprising the steering wheel angle correction device according to claim 1. Description: