JP2004255910A - Steering control device and its program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering control device capable of smoothening the motions of a nose-gear leg at the time of steering. <P>SOLUTION: The steering control device is to control the opening and closing operation of a valve of a hydraulic actuator for steering the nose-gear leg of an airplane and is arranged so that a valve signal ϕLV consisting of a plurality of pulses is emitted to the valve from the control device in case the actual steering angle RA as the actual angle of the nose-gear leg is smaller than the target lower limit value TA2-x for the target angle TA2 as the angle to which the nose-gear leg are to be steered. At this time, the oil pressure supplied to the actuator rises intermittently in conformity to the pulses, an excessive rise of the oil pressure can be suppressed. As a result, the actual steering angle RA can be prevented from becoming greater than the target lower limit value TA2-x. Accordingly when the target angle TA increases at a constant rate, the actual steering angle RA can also increase continuously in follow-up after the target angle TA, and it is possible to smoothen the steering operation. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steering control device and a program therefor, and more particularly, to a steering control device and a program for controlling opening and closing of a valve of a hydraulic actuator that steers a steered wheel.
[0002]
[Prior art]
Steering of the nose gear of the aircraft is performed by a hydraulic actuator via a rudder pedal in the cockpit. At the time of steering, the target angle which is the angle to be steered by the front leg is calculated based on the depression amount of the rudder pedal of the pilot. On the other hand, the stroke amount of the hydraulic actuator is detected as an SPS (Steering Position Sensor) signal, and an actual angle of the front leg (hereinafter, referred to as an actual steering angle) is calculated based on the detected SPS signal. If there is a difference between the actual steering angle and the target angle, the valve is opened upon receiving the activated valve signal. 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. 8 shows changes in the valve signal, the hydraulic pressure, and the stroke amount of the hydraulic actuator when the aircraft is steered. Referring to FIG. 8, at time t0, target angle TA (Target Angle) is calculated. On the other hand, the actual steering angle RA (Real Angle) is also calculated based on the SPS signal. C in FIG. 8 indicates the stroke amount of the hydraulic actuator when the actual steering angle is RA. B indicates a stroke amount corresponding to the calculated target angle TA. In order to set the actual steering angle RA to the same value as the target angle TA, the cylinder of the hydraulic actuator needs to increase the stroke amount ΔC1. At this time, the valve signal φV is activated to the H (logic high) level at time t0. As a result, the valve is opened and the hydraulic actuator operates. At time t2 when the stroke amount increases by ΔC1, the valve signal φV is deactivated to the L level (logic low) level, and the valve is closed. By the above operation, the stroke amount increases by ΔC1.
[0004]
However, the hydraulic pressure of the hydraulic actuator cannot quickly respond to changes in the valve signal φV. In other words, the oil pressure starts increasing at time t1 when a predetermined time has elapsed since activation of valve signal φV. Furthermore, since the oil pressure reacts with a delay with respect to the valve signal φV, the oil pressure remains after time t2 when the valve signal φV is deactivated, and returns to the oil pressure before time t1 at time t3. As a result, the stroke of the hydraulic actuator is increased by ΔC2.
[0005]
The steering control described above has a problem that the front legs do not operate smoothly during steering.
[0006]
FIG. 9 shows the relationship between the target angle and the actual steering angle when the depression amount of the rudder pedal per unit time is constant. When the pilot depresses the rudder pedal by a fixed amount per unit time, the target angle TA also increases by a fixed amount per unit time. Here, the target angle TA has a margin ± x. This is to prevent hunting. If the actual steering angle RA is larger than the target angle lower limit TA-x and smaller than the target angle upper limit TA + x, it is regarded as the same as the target angle TA.
[0007]
At time t0, the actual steering angle RA becomes smaller than the target angle lower limit TA-x, so that the valve signal φV is activated. As a result, the hydraulic actuator operates at time t1, and the actual steering angle RA starts to increase. At time t2, the actual steering angle RA increases beyond the target lower limit value TA-x by increasing the angle △ RA1 (（C1 in the stroke amount). Therefore, the actual steering angle RA is considered to be the same as the target angle TA.
[0008]
However, as described with reference to FIG. 8, the oil pressure continues to increase even after time t2. Accordingly, the actual steering angle RA further increases by an additional angle △ RA2 (△ C2 in the stroke amount) and stops at time t3.
[0009]
As a result, the hydraulic actuator stops operating as much as the actual steering angle RA has increased by the angle △ RA2, and again at time t4 when the target angle lower limit TA-x has increased beyond △ RA2. Start operation. As a result, the actuator operates intermittently. Therefore, the front leg also operates intermittently, does not move smoothly, and the actual steering angle becomes step-like as shown in FIG.
[0010]
[Patent Document 1]
JP-A-8-133189 [Patent Document 2]
JP-A-10-89303
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a steering control device capable of smoothing the operation of a front leg during steering and a program therefor.
[0012]
[Means for Solving the Problems]
A steering control device according to the present invention is a steering control device for controlling the opening and closing of a valve of a hydraulic actuator that steers a steered wheel. Comparing means for comparing the actual steering angle with the actual steering angle, which is an actual angle, and, as a result of the comparison, when it is determined that the actual steering angle is within the target angle margin, the actual steering angle is within the target angle margin. Opening and closing means for opening and closing the valve intermittently.
[0013]
The operation of the hydraulic actuator becomes slow due to a response delay of the hydraulic pressure to the opening and closing of the valve. Therefore, when the actual steering angle is not the same as the target angle, the valve is opened and closed intermittently. As a result, a state in which the valve is closed intermittently occurs until the actual steering angle falls within the margin of the target angle. Therefore, an increase in fluid pressure due to a response delay can be suppressed. As a result, excessive movement of the actuator can be prevented, and a large increase in the actual steering angle can be suppressed.
[0014]
Preferably, the steering control device calculates a target error obtained by subtracting the actual steering angle from the target angle, and calculates a ratio of a time of opening the valve to a time of opening and closing the valve once based on the target error. Determining means for determining the duty ratio.
[0015]
More preferably, the determining means determines a larger duty ratio as the target error is larger.
[0016]
In this case, as the target error is larger, the ratio of the time during which the valve is opened during the valve opening / closing time is increased. As a result, the operating speed of the hydraulic actuator increases, and the steering rate increases. When the target error is large, it is necessary to quickly change the direction of the steered wheels. However, according to the present invention, when the target error is small, the steering can be controlled smoothly, and the steering rate increases as the target error increases. This allows for quick steering. In particular, when the present invention is applied to a steering wheel of an aircraft, safety during traveling of the aircraft can be ensured.
[0017]
Preferably, when the target error is larger than a predetermined value, the determining means determines the duty ratio such that the steering rate of the steered wheels becomes the predetermined steering rate.
[0018]
In this case, even if the target error is large, a steering rate necessary for safety during traveling can be secured, and particularly when the present invention is applied to the steered wheels of the aircraft, the safety during traveling of the aircraft can be secured.
[0019]
BEST MODE FOR CARRYING OUT 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 have the same reference characters allotted, and description thereof will be referred to.
[0020]
1. First Embodiment [Overall Configuration of Steering Control System]
Referring to FIG. 1, a steering control system 10 includes a rudder pedal 1, a rudder detection circuit 2, a control device 3, a valve 4, a hydraulic power source 6, an actuator 8, and a stroke amount detection circuit 9.
[0021]
The rudder detection circuit 2 detects the depression amount of the rudder pedal 1 and transmits the detection result to the control device 3. A region 82 to which oil is supplied and a region 83 are formed in the actuator 8 via a rod 81. The actuator 8 drives the rod 81 to rotate a front leg (not shown).
[0022]
The oil is supplied to the actuator 8 by a hydraulic pressure source 6 and two valves (a right valve 41 and a left valve 42). A hydraulic pipe 71 is arranged from the hydraulic pressure source 6 to the right valve 41 and the left valve 42. A hydraulic pipe 72 is arranged from the right valve 41 to a region 82 in the actuator 8. A hydraulic pipe 73 is arranged from the left valve 42 to a region 83 in the actuator 8.
[0023]
When the right valve 41 is opened by a valve signal φRV (Right Valve) output from the control device 3, oil flows from the hydraulic pressure 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 to the right. 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 to the left. The stroke amount detection circuit 9 detects the movement amount of the rod 81 as a stroke amount, and transmits the detection result to the control device 3.
[0024]
The control device 3 includes a CPU (Central Processing Unit) 31 and a storage device 32. The 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 circuit 2 and the stroke amount detection circuit 9 to control each valve. By installing a steering control program in the storage device 32 in the control device 3, the steering control system 10 can execute the steering control process.
[0025]
[Steering control processing operation]
Referring to FIG. 2, when the ladder pedal 1 is depressed, the ladder detection circuit 2 detects the depression amount of the ladder pedal 1, and the control device 3 receives the detection result (S1). After receiving the detection result, the control device 3 calculates the target angle TA based on the detection result (S2). Information on the relationship between the depression amount of the rudder pedal 1 and the target angle TA is stored in the storage device 32 in advance.
[0026]
Next, the control device 3 calculates the actual steering angle RA (S3, S4). Specifically, the stroke amount detection circuit 9 detects the stroke amount C of the rod 81 in the actuator 8, and transmits the detection result to the control device 3 (S3). The control device 3 calculates the actual steering angle RA based on the detection result (S4). Note that information on the relationship between the stroke amount C and the actual steering angle RA is stored in the storage device 32 in advance.
[0027]
Here, the control device 3 calculates a target error EA (Error Angle) according to the following equation (1) (S5).
Target error EA = target angle TA−actual steering angle RA (1)
[0028]
How to use the target error EA will be described later.
[0029]
After calculating the target angle TA, the actual steering angle RA, and the target error EA, the control device 3 determines whether or not the actual steering angle RA can be regarded as being equal to the target angle TA (S6). In the steering control method according to the present embodiment, a margin ± x is provided for the target angle TA.
[0030]
When the actual steering angle RA is within the margin ± x of the target angle TA, that is, when the actual steering angle RA is larger than the target angle lower limit TA-x and smaller than the target angle upper limit TA + x. , The control device 3 considers that the actual steering angle RA is the same as the target angle TA. Therefore, in this case, the control device 3 outputs L-level valve signals φRV and φLV to turn off both the right valve 41 and the left valve 42. As a result, the actuator 8 does not operate.
[0031]
In FIG. 3, when the target angle at time t1 is TA1 and the actual steering angle is RA, the actual steering angle RA is smaller than the target angle TA1, but larger than the target angle lower limit TA1-x. Therefore, the control device 3 considers that the actual steering angle RA is the same as the target angle TA1. As a result, the control device 3 closes the right valve 41 and the left valve 42 and does not operate the actuator 8.
[0032]
On the other hand, if the actual steering angle RA is out of the range of the margin ± x at the target angle TA, the control device 3 determines that the actual steering angle RA does not satisfy the target angle TA (S6).
[0033]
In FIG. 3, it is assumed that the target angle becomes TA2 at time t20 as a result of depression of the rudder pedal 1 after time t10. In this case, the actual steering angle RA1 is smaller than the target angle lower limit value TA2-x of the target angle TA2. Therefore, the control device 3 determines that the actual steering angle C1 is different from the target angle TA2 (S6).
[0034]
At this time, the control device 3 also selects a valve to be controlled. That is, when the actual steering angle RA is larger than the target angle upper limit value TA + x, it is determined that the front leg needs to be rotated rightward, and the valve to be controlled is selected as the right valve 41. Therefore, the valve signal φLV is not output to the left valve 42. On the other hand, in the case of FIG. 3, the control device 3 determines that it is necessary to rotate the front leg in the left direction, and selects the valve to be controlled as the left valve 42. Therefore, the valve signal φRV is not output to the right valve 41.
[0035]
After selecting the valve, the control device 3 controls the left valve 42 so that the actual steering angle RA satisfies the target angle TA2 (S7). During the control in step S7, the control device 3 outputs the valve signal φLV so that the steering operation becomes smooth.
[0036]
Specifically, referring to FIG. 4, at time t20, control device 3 outputs valve signal φLV. Here, the valve signal φLV includes a plurality of pulses P as shown in FIG. Here, the pulse width indicates a time during which the left valve 42 is open (hereinafter, referred to as an ON time). On the other hand, the time during which the pulse P is not output is a time when the left valve 42 is closed (hereinafter, referred to as an off time).
[0037]
The actuator 8 has poor followability to the valve signal φV. This is because the response of the hydraulic pressure to the valve signal φV is slow, but it is difficult to improve the followability as long as a hydraulic actuator is used.
[0038]
Therefore, the left valve 42 is turned on / off a plurality of times by outputting the valve signal φLV as a pulse train until the actual steering angle RA reaches the target angle lower limit value TA2-x. As a result, although the hydraulic pressure OP is delayed after the pulse P and rises after the on-time elapses, the supply of oil is stopped during the off-time, so that the rise of the hydraulic pressure OP after the on-time can be suppressed. Accordingly, excessive movement of the rod 81 can be prevented, and as a result, the actual steering angle RA can be suppressed from significantly increasing beyond the target angle lower limit TA2-x.
[0039]
FIG. 5 shows a simulation result of steering control according to the embodiment of the present invention. The vertical axis of the graph in FIG. 5 indicates the stroke amount of the actuator 8 (corresponding to the actual steering angle RA), and the horizontal axis indicates the depression amount of the rudder pedal 1 (corresponding to the target angle TA). Here, the depression amount of the rudder pedal 1 is constant per unit time. As shown in FIG. 5, the stroke amount continuously increases as the depression amount of the rudder pedal increases. That is, the actual steering angle RA continuously increases with respect to the target angle TA. By the above operation, the steering operation becomes smooth, and the intermittent operation seen in the conventional steering control can be suppressed.
[0040]
Here, the duty ratio (duty ratio) = on time / (on time + off time) is determined by the relationship between the friction of the wheels of the front legs on the ground and the performance of the actuator 8.
[0041]
2. Second Embodiment In the first embodiment described above, the steering operation can be made smooth, but depending on the duty ratio, a predetermined steering rate may not be satisfied. This is because if the off-time is longer than the on-time, the operation of the front legs is delayed. If the target error is large, the steering rate cannot be lower than a predetermined value for the safety of the steering of the aircraft. Therefore, it is desirable that the steering operation be maintained smoothly and that the steering rate be satisfied.
[0042]
The overall configuration of the steering control system according to the second embodiment is the same as that of FIG. The operation flow is the same except for step S7 in FIG.
[0043]
FIG. 6 shows the operation of step S7 in FIG. 2 in the second embodiment. Referring to FIG. 6, control device 3 determines a duty ratio based on the magnitude of target error EA calculated in step S5 (S71 to S77). Specifically, in order to satisfy a predetermined steering rate, if the target error EA is large, the duty ratio is large (ie, the on-time with respect to the off-time is large), and if the target error EA is small, the duty ratio is small (ie, the off-time). To reduce the on-time for
[0044]
In the present embodiment, a case will be described in which the control device 3 controls the left valve 42 as a result of the actual steering angle RA being smaller than the target angle lower limit TA-x.
[0045]
As shown in FIG. 7, the angles NA (Narrow Angle), MA (Middle Angle), and WA (Wide Angle) from the target angle TA are set as threshold angles for changing the duty ratio. The duty ratios for the threshold angles NA, MA, and HA are predetermined as DNA, DMA, and DWA, respectively. Here, it is assumed that DNA <DMA <DWA. Information on the relationship between each threshold angle and the duty ratio is stored in the storage device 32.
[0046]
Referring to FIGS. 6 and 7, first, control device 3 determines whether or not target error EA is smaller than threshold angle NA (S71). As a result of the determination, when the target error EA is smaller than the threshold angle NA (S71), the control device 3 determines the duty ratio to be DNA (S72). For example, the DNA at this time is set to 10 (msec) / 50 (msec). As a result, the control device 3 outputs a valve signal φLV of a pulse train having an ON time of 10 msec and an OFF time of 40 msec.
[0047]
On the other hand, as a result of the determination, if the target error EA is equal to or larger than the threshold angle NA (S71), the control device 3 determines whether the target error EA is smaller than the threshold angle MA (S73). As a result of the determination, when the target error EA is smaller than the angle MA (S73), the control device 3 determines the duty ratio to be DMA (S74). For example, DMA = 10 (msec) / 40 (msec). The reason why the off-time is shorter than that of the DNA is to increase the driving speed of the actuator 8 by shortening the off-time and, consequently, to increase the steering rate.
[0048]
As a result of the determination, when the target error EA is equal to or larger than the angle MA (S73), the control device 3 determines whether the target error EA is smaller than the threshold angle WA (S75). As a result of the determination, when the target error EA is smaller than the threshold angle WA (S75), the control device 3 determines the duty ratio to be DWA (S76). For example, DWA = 10 (msec) / 30 (msec). On the other hand, when the target error EA is larger than the threshold angle WA (S75), the control device 3 performs the conventional control operation. That is, in this case, the control device 3 does not output the valve signal φLV as a pulse train, but continuously outputs the H-level valve signal φLV until the actual steering angle RA becomes larger than the target angle lower limit value TA-x. I do. This is because, since the target error EA is large, priority is given to securing the steering rate over smoothness of the operation.
[0049]
In the steering control system according to the second embodiment, the duty ratio is determined according to the angle difference between target angle TA and actual steering angle RA. As a result, while ensuring the smoothness of operation as much as possible, and when the target error becomes larger than a predetermined value, the steering rate is gradually increased to a predetermined steering rate that can ensure the safety of improving the operation of the aircraft. be able to.
[0050]
In the present embodiment, the operation of the steering control system when the actual steering angle RA is smaller than the target lower limit value TA-x is described, but the actual steering angle RA is larger than the target upper limit value TA + x. The same applies to the operation method of the steering control system when it is large (that is, the control method of the right valve 41). Further, in the present embodiment, the duty ratio with respect to the threshold angle is fixed, but the control device 3 continuously changes the duty ratio in accordance with the angle difference between the target angle TA and the actual steering angle RA. You may.
[0051]
The embodiment of the present invention has been described above, but the above-described embodiment is merely an example for implementing 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 system of FIG. 1;
FIG. 3 is a diagram for explaining a relationship between a target angle and an actual steering angle in the operation flow of FIG. 2;
FIG. 4 is a waveform chart for explaining the operation in step S7 of FIG.
FIG. 5 is a diagram of a simulation result when the operation flow of FIG. 2 is performed.
FIG. 6 is a flowchart showing an operation of a steering control system according to another embodiment.
FIG. 7 is a diagram for explaining a relationship between a target angle and an actual steering angle in the operation flow of FIG. 6;
FIG. 8 is a diagram showing changes in a valve signal, hydraulic pressure, and a stroke amount of a hydraulic actuator by conventional steering control of an aircraft.
FIG. 9 is a diagram showing a relationship between a target angle and an actual steering angle by conventional steering control.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 rudder pedal 2 rudder detection circuit 3 control device 8 actuator 9 stroke amount detection circuit 10 steering control system 41 right valve 42 left valve 81 cylinder φLV, φRV valve signal

Claims (5)

A steering control device for controlling opening and closing of a valve of a hydraulic actuator that steers a steered wheel,
A comparison unit that compares a target angle, which is an angle to be steered by the steered wheels, with an actual steering angle, which is an actual angle of the steered wheels,
As a result of the comparison, when it is determined that the actual steering angle is outside the margin of the target angle, an opening and closing unit that opens and closes the valve intermittently until the actual steering angle is within the margin of the target angle. A steering control device comprising: The steering control device according to claim 1, further comprising:
Calculating means for calculating a target error obtained by subtracting the actual steering angle from the target angle;
Determining means for determining a duty ratio, which is a ratio of a time when the valve is once opened to a time when the valve is once opened, based on the target error. The steering control device according to claim 2,
The steering control device according to claim 1, wherein the determining unit determines the duty ratio to be larger as the target error is larger. The steering control device according to claim 3, wherein
The steering control device according to claim 1, wherein said determining means determines said duty ratio such that a steering rate of said steered wheels becomes a predetermined steering rate when said target error is larger than a predetermined value. A steering control program for causing a computer to function as the means according to claim 1.

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