JP4102234B2 - Steering control device and program thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steering control device and a program thereof, and more particularly to a steering control device that steers a steered wheel and a program thereof.
[0002]
[Prior art]
Steering of the front legs of the aircraft is performed by a hydraulic actuator via a ladder pedal in the cockpit. At the time of steering, a target angle, which is an angle at which the front leg should be steered, is calculated based on the amount of pilot pedal depression. On the other hand, the stroke amount of the hydraulic actuator is detected as an SPS (Steering Position Sensor) signal, and the actual angle of the front leg (hereinafter referred to as the actual steering angle) is calculated based on the detected SPS signal. When there is a difference between the actual steering angle and the target angle, the activated valve signal is received and the valve is opened. As a result, the hydraulic actuator operates to rotate the front leg. The valve is kept open until the actual steering angle becomes substantially the same as the target angle, and the hydraulic actuator operates.
[0003]
FIG. 4 shows the relationship between the target angle and the actual steering angle when the aircraft is steered. When the pilot depresses the ladder pedal by a certain amount per unit time, the target angle TA also increases by a certain amount per unit time (time t0 to t12). Here, the target angle TA has a margin ± NX. If the actual steering angle RA is larger than the target angle lower limit value TA−NX and smaller than the target angle upper limit value TA + NX, it is regarded as the same as the target angle TA.
[0004]
At time t10, the actual steering angle RA becomes smaller than the target angle lower limit TA-NX, and steering control is started. As a result, the hydraulic actuator operates at time t11, and the actual steering angle RA begins to increase. Note that the period between times t10 and t11 is a time generated due to a delay in response of the hydraulic pressure. Here, when the pilot stops stepping on the ladder pedal at time t12, the subsequent target angle TA becomes constant. At this time, the actual steering angle RA becomes larger than the target angle lower limit TA-NX at time t13. Therefore, the valve signal becomes inactive and the operation of the actuator stops. As a result, the movement of the front leg stops at time t14.
[0005]
However, the front leg tires are twisted during the steering operation at times t11 to t14. As a result, at time t14 when the force of the actuator is no longer received, a force is exerted to restore the twist of the front leg tire, and the front leg is returned to the original direction (hereinafter, this phenomenon is referred to as tire return). By this tire return, the actual steering angle decreases by an angle D. As a result, the actual steering angle RA becomes smaller than the target lower limit value TA-NX at time t15, and the steering control is started again. Therefore, the front leg receives a force from the actuator and rotates again.
[0006]
Since the above operation is repeated, even when the pilot makes the amount of depression of the ladder pedal constant and the target angle TA becomes constant, the front leg rotates intermittently and hunting occurs.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-133189
[Problems to be solved by the invention]
The objective of this invention is providing the steering control apparatus which can prevent hunting, and its program.
[0009]
[Means for Solving the Problems]
A steering control device according to the present invention is a steering control device that controls steering of a steered wheel so that an actual steering angle that is an actual angle of the steered wheel approaches a target angle that is an angle that the steered wheel should steer. Control means, target angle change determination means, and margin setting means. The control means determines whether the actual steering angle is within the margin of the target angle, and drives the steering wheel when it is outside the margin, and steers the steering wheel so as to stop driving the steering wheel when it is within the margin. To control. The target angle change determining means determines whether or not the target angle has changed. The margin setting means determines whether or not the actual steering angle is within a predetermined range of the target angle when the target angle is not changed, and widens the margin by a predetermined amount when within the predetermined range.
[0010]
The steering control device according to the present invention determines whether or not the actual steering angle is within a predetermined range of the target angle. As a result of the determination, if the actual steering angle is within a predetermined range, the margin is increased by a predetermined amount. If the actual steering angle is within the margin of the target angle, it is determined that it is no longer necessary to steer the steered wheel, and the steering operation ends. However, since the steering wheel tire is twisted by the steering operation, the tire returns after the steering operation ends, and the actual steering angle returns. Again, steering control is started so that the actual steering angle falls within the margin, and as a result, the steered wheels are hunted. In the present invention, since the margin is increased by a predetermined amount, the actual steering angle causing the tire return does not go out of the margin. As a result, the steering wheel does not cause hunting.
If the margin is widened when the target angle is changing, the margin is widened while the steered wheels are being steered, and the actual steering angle is prevented from approaching the target angle. Therefore, when the target angle has not changed and the actual steering angle is within the predetermined range, it is possible to prevent the actual steering angle from moving away from the target angle during the change of the target angle.
[0011]
Preferably, the predetermined range is smaller than the margin.
[0012]
The predetermined range may be the same as the margin, but in this case, as a result of the steering operation, the margin is increased as soon as the actual steering angle falls within the margin of the target angle. The azimuth may be far from the target angle. Therefore, if the predetermined range is made smaller than the margin and the actual steering angle falls within the target angle margin, the tire return will not occur until the actual steering angle approaches the target angle to some extent. This prevents the actual steering angle and the target angle from being left greatly different.
[0015]
Preferably, the steering control device further includes detection means. The detecting means detects a plurality of target angles within a predetermined period. The target angle change determining means includes an average value calculating means and a comparing means. The average value calculating means calculates the average value of the target angles within a predetermined period based on the plurality of target angles detected by the detecting means. The comparison means compares the average value in one predetermined period calculated by the average value calculation means with the average value in the other predetermined period, and if the difference between them is smaller than the predetermined value, the target angle has not changed. to decide.
[0016]
In this case, the steering control device calculates an average value of the target angles within one predetermined period. For example, the target angle is detected a plurality of times within the period from the operation start (0 ms) to 50 ms, and the average value of the target angles is calculated. On the other hand, the steering control device calculates the average value of the target angles in the same manner during other predetermined periods. For example, the average value of the target angles in a period from 10 ms after the start of operation to 60 ms is calculated. Thereafter, the steering control device compares the average value of the target angles within one predetermined period with the average value of the target angles within another predetermined period. As a result of the comparison, when the difference between the average values of one predetermined period and another predetermined period is smaller than the predetermined value, the steering control device determines that the target angle has not changed. The detection result of the target angle may include noise. Therefore, if the target angle determination means uses the detection result of the target angle as a direct determination material, even when the target angle has not changed, it may be mistaken for the target angle to change. In the present invention, since the determination is made using the average value of the detected plurality of target angles, it is possible to prevent the target angle determination means from making an erroneous determination.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof is incorporated.
[0018]
[Overall configuration of steering control system]
Referring to FIG. 1, a steering control system 10 includes a ladder pedal 1, a ladder detection device 2, a steering control device 3, a valve 4, a hydraulic source 6, an actuator 8, and a stroke amount detection device 9. Prepare.
[0019]
The ladder detection device 2 detects the depression amount of the ladder pedal 1 and transmits the detection result to the steering control device 3. A region 82 and a region 83 to which oil is supplied through the rod 81 are formed in the actuator 8. The actuator 8 drives the rod 81 to rotate a front leg (not shown).
[0020]
Oil is supplied to the actuator 8 by a hydraulic pressure source 6 and two valves (the right valve 41 and the left valve 42). A hydraulic pipe 71 is disposed from the hydraulic source 6 to the right valve 41 and the left valve 42. A hydraulic pipe 72 is disposed from the right valve 41 to the region 82 in the actuator 8. A hydraulic pipe 73 is arranged from the left valve 42 to the region 83 in the actuator 8.
[0021]
When the right valve 41 is opened by the valve signal φRV (Right Valve) output from the steering control device 3, oil flows from the hydraulic source 6 into the region 82. At this time, the rod 81 moves in the −X direction on the drawing, and as a result, the actuator 8 rotates the front leg in the right direction. On the other hand, when the left valve 42 is opened by the valve signal φLV (Left Valve), oil flows from the hydraulic pressure source 6 into the region 83. At this time, the rod 81 moves in the X direction on the drawing, and as a result, the actuator 8 rotates the front leg in the left direction. The stroke amount detection device 9 detects the movement amount of the rod 81 as a stroke amount, and transmits the detection result to the steering control device 3.
[0022]
The steering control device 3 includes a computer and includes a CPU (Central Processing Unit) 31 and a storage device 32. The steering control device 3 outputs valve signals φRV and φLV to the right valve 41 and the left valve 42 based on the detection results of the ladder detection device 2 and the stroke amount detection device 9, respectively, and controls each valve. The steering control system 10 can execute a steering control process by installing a steering control program in the storage device 32 in the steering control device 3.
[0023]
[Steering control operation]
Referring to FIG. 2, first, the steering control device 3 calculates a target angle TA (S1). Specifically, when the ladder pedal 1 is depressed, the ladder detection device 2 detects the depression amount of the ladder pedal 1, and the steering control device 3 receives the detection result. The steering control device 3 calculates the target angle TA based on the received detection result. Information on the relationship between the depression amount of the ladder pedal 1 and the target angle TA is stored in the storage device 32 in advance.
[0024]
Next, the steering control device 3 calculates the actual steering angle RA (S2). Specifically, the stroke amount detection device 9 detects the stroke amount of the rod 81 in the actuator 8 and transmits the detection result to the steering control device 3. The steering control device 3 calculates the actual steering angle RA based on the detection result. Information on the relationship between the stroke amount and the actual steering angle RA is stored in the storage device 32 in advance.
[0025]
Here, the steering control device 3 calculates a target error EA (Error Angle) by the following equation (1) (S3).
Target error EA = target angle TA−actual steering angle RA (1)
The target error EA is used in step S6 described later.
[0026]
Subsequently, the steering control device 3 determines whether or not the target angle TA has changed (S4, S5). Specifically, the steering control device 3 calculates an average value of a plurality of target angles detected within one predetermined period, and compares the calculated average value with an average value of target angles within another predetermined period. For example, when the steering control device 3 acquires the target angle TA every 10 ms and the acquisition of the target angle TA in step S1 is the 11th time, the steering control device 3 sets the predetermined period as 100 ms, An average value (first average value) of the target angles TA from the 10th time to the 10th time and an average value (second average value) of the target angles from the 2nd time to the 11th time are calculated (S4). Next, the steering control device 3 compares the first average value with the second average value, and determines whether or not the target angle TA has changed (S5). Specifically, the steering control device 3 determines whether or not the absolute value of the difference between the first average value and the second average value is smaller than a predetermined value. When it is smaller than the predetermined value, the steering control system 10 determines that the target angle TA has not changed, and when it is larger than the predetermined value, it determines that the target angle TA has changed. In step S1, the detection result of the depression amount of the ladder pedal 1 may include noise. If the methods of steps S4 and S5 are used, it is possible to prevent the steering control device 3 from erroneously determining that the target angle TA has changed based on the detection result including noise.
[0027]
At time t1 in FIG. 3, the steering control device 3 determines that the target angle TA has changed (S5). At this time, the steering control device 3 controls the front leg steering (S9, S10) after setting the margin as usual (margin = ± NX) (S7). Specifically, the steering control device 3 determines whether or not the actual steering angle RA is within the margin of the target angle TA at time t1 (S9). That is, the steering control device 3 determines whether the actual steering angle RA is smaller than the target upper limit value TA + NX of the target angle TA and larger than the target lower limit value TA-NX. At time t1, since the actual steering angle RA is smaller than the target lower limit value TA-NX, the steering control device 3 determines that the actual steering angle RA is outside the margin of the target angle TA. At this time, the steering control device 3 activates the valve signal φVL (S10). The left valve 42 opens upon receiving the activated valve signal φVL, and oil flows into the actuator 83. The rod 81 of the actuator 8 moves due to the inflow of oil. As a result, the front leg rotates to the left based on the drive of the actuator 8. With the above operation, the steering control system 10 drives the front legs until the actual steering angle RA becomes larger than the lower limit value TA-NX of the target angle TA.
[0028]
Next, after time t2 in FIG. 3, the steering control device 3 determines that the target angle TA has not changed (S5). At this time, the steering control device 3 determines whether or not the actual steering angle RA is within a predetermined range B of the target angle TA. Specifically, it is determined whether or not the target error EA is smaller than the predetermined range B (S6). Since the target error EA is larger than the predetermined range B at time t2, the steering control device 3 sets the margin as usual (margin = ± NX) (S7). Thereafter, the steering control device 3 drives the front legs until the actual steering angle RA becomes larger than the target lower limit value TA-NX (S9, S10).
[0029]
Since the actual steering angle RA is within the target lower limit TA-NX at time t3, the steering control device 3 determines that the actual steering angle RA is within the margin of the target angle TA (S9). At this time, the steering control device 3 stops driving the front legs. Specifically, the steering control device 3 deactivates the valve signal φVL (S11). As a result, the supply of hydraulic pressure to the actuator 8 is stopped. However, since the hydraulic pressure remains in the actuator 8, the front legs continue to be driven until time t5 when the remaining hydraulic pressure decreases after time t3.
[0030]
At time t4 when the front leg is driven by the remaining hydraulic pressure, the steering control device 3 determines that the target error EA is smaller than the predetermined range B (S6). At this time, the steering control device 3 increases the margin from NX to LX (S8).
[0031]
After time t3, the actual steering angle RA is within the target lower limit TA-NX, and therefore the steering control device 3 stops driving the front legs. Therefore, the front leg receives no force from the actuator 8 after time t5 when the hydraulic pressure remaining in the actuator 8 decreases. However, since the front legs have been steered from time t1, the front leg tires are twisted. As a result, tire return may occur after time t5, and the actual steering angle RA may become smaller than the target lower limit TA-NX. In the present embodiment, since the steering control device 3 increases the margin from NX to LX, the actual steering angle RA does not fall outside the margin. Therefore, the front leg is not driven after time t5. As a result, hunting based on tire return can be prevented.
[0032]
When the predetermined range B = NX, the actual steering angle RA returns to the position of the target lower limit value TA-NX-D due to the tire return amount D, and the actual steering angle RA is far from the target angle TA. there is a possibility. Therefore, by setting the predetermined range B within the range from the target lower limit value TA-NX to the target value TA, the actual steering angle RA after the tire return has occurred can be prevented from being far from the target angle TA. The predetermined range B is preferably smaller than a value obtained by subtracting the tire return amount D from the margin LX.
[0033]
The average value of the target angle TA in S4 may be calculated every predetermined period such as 50 ms, for example. Further, in the present embodiment, the operation of the steering control system in the case where the actual steering angle RA is smaller than the target lower limit value TA-NX is described, but the actual steering angle RA is smaller than the target upper limit value TA + NX. The operation method of the steering control system when it is large (that is, the control method of the right valve 41) is the same. In the present embodiment, the steering control device for the front legs of the aircraft has been described. However, the same effect can be obtained by applying the steering control device of the present invention to other steered wheels where tire return occurs.
[0034]
While the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment, and can be implemented by appropriately modifying the above-described embodiment without departing from the spirit thereof.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a steering control system according to an embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the control device in FIG. 1;
FIG. 3 is a timing chart showing changes in target angle and actual steering angle during the operation shown in FIG. 2;
FIG. 4 is a timing chart showing changes in a target angle and an actual steering angle by conventional steering control.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ladder pedal 2 Ladder detection apparatus 3 Control apparatus 4 Valve 8 Actuator 9 Stroke amount detection apparatus 10 Steering control system 81 Rod

Claims (4)

A steering control device that controls steering of the steered wheel so that an actual steered angle that is an actual angle of the steered wheel approaches a target angle that is an angle that the steered wheel should steer;
It is determined whether or not the actual steering angle is within the margin of the target angle, and the steering wheel is driven when it is outside the margin, and the steering wheel is stopped when it is within the margin. Control means for controlling the steering of the wheel;
Target angle change judging means for judging whether or not the target angle has changed;
When the target angle has not changed, it is determined whether or not the actual steering angle is within a predetermined range of the target angle, and when the target angle is within the predetermined range, a margin setting means for expanding the margin by a predetermined amount is provided. A steering control device. The steering control device according to claim 1,
The steering control device according to claim 1, wherein the predetermined range is smaller than the margin. The steering control device according to claim 1 or 2 , further comprising:
Provided with detecting means for detecting a plurality of target angles within a predetermined period,
The target angle change determining means includes
An average value calculating means for calculating an average value of the target angles within the predetermined period based on a plurality of target angles detected by the detecting means;
The average value in one predetermined period calculated by the average value calculating means is compared with the average value in the other predetermined period, and when the difference is smaller than the predetermined value, it is determined that the target angle has not changed. A steering control device. The steering control program for functioning a computer as each means of any one of Claims 1-3 .

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