JP3720189B2 - Actuator control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a failure detection apparatus provided in a system for controlling a control surface actuator of an aircraft.
[0002]
[Prior art]
A system that controls a control surface actuator of an aircraft by a mechanism including a motor driver, a motor, a speed reducer, and the like is required to have high safety and reliability. When a failure occurs in an actuator, it is an important issue to detect this at an early stage and to perform a quick and accurate process.
[0003]
In the prior art, an actuator model having a transfer function substantially equivalent to that of an actual actuator with clear control characteristics is assumed. This actuator model calculates the command value input signal based on the control characteristics of the actual actuator (actual machine) to obtain an approximate value of the actuator position as a model. From the transfer function, the first order approximation, the second order approximation, or the third order approximation may be indicated. In any approximation calculation, the estimated position signal (S ₁ ) output from the actuator model corresponding to the command value and the actual When the deviation (e) from the actual operation signal (S ₂ ) of the control surface actuator indicates an absolute value equal to or greater than a predetermined detection threshold (threshold value), a failure signal is output via the time delay circuit.
[0004]
Therefore, since it takes a certain amount of time for the failure signal to reach a predetermined signal level (that is, the failure signal level) that can be determined as a failure, the failure determination may be delayed. Moreover, if the time during which the deviation (e) exceeds the detection threshold is extremely short, it may occur that the failure is not determined.
A typical example of the prior art is shown in FIG. FIG. 4 shows a model circuit having a transfer function similar to that of an actuator and a motor (for example, a stepping motor) in order to detect the failure early and reliably when an actuator failure occurs. This signal is input and the output is compared with the operating position of the actual actuator to detect an abnormal operating state due to a failure.
[0005]
In the control system of FIG. 4, the command value C is given to the motor 43 via the adder 41 and the motor driver 42, and the adder 41 adds the feedback signal and the command value C indicating the target position, and the deviation between the two signals. When a signal is input to the motor driver, the motor 43 drives the speed reducer 44 to control the position of the actuator. The position of the actuator is detected by a feedback sensor 45, and the detected information is fed back to the adder 41 via the demodulator 46. The adder 41, the motor driver 42, the motor 43, and the like constitute a forward circuit 47 that operates the actuator based on the command value C, and the feedback sensor 45 and the demodulator 46 move the actuator operating position to the command input side. A feedback circuit 48 for feedback is configured.
[0006]
In the prior art, the command value C is input in parallel with the adder 41 to an actuator model 49 having a transfer function of the second order or the third order substantially equal to the forward circuit, and the output (S ₁ ) and demodulation of the actuator model The deviation signal (e) from the feedback signal (S ₂ ) from the calculator 46 is input from the adder 50 to the absolute value calculation circuit 51, and the absolute value output is input to the comparison circuit 52. The comparison circuit 52 has an immortal range up to a predetermined detection threshold level. When the deviation signal from the adder 50 is equal to or higher than the detection threshold, that is, the actual operating position of the actuator is within a predetermined error range with respect to the reference position indicated by the model 49. When the deviation is out of the range, a fault signal is output from the deviation signal comparison circuit 52 via the time delay circuit 53 having a predetermined delay characteristic.
[0007]
In the prior art, the current limiter 54 acts to limit the output torque so that the output of the actuator does not exceed the rated value even if an overload is applied to the actuator. As a result, the actuator cannot follow the command, and the actuator position changes forcibly. Therefore, it is necessary to suppress malfunctions such as generation of a failure signal by suppressing the detection sensitivity of the actuator position.
[0008]
It is difficult for this control system to determine whether or not a failure actually occurs in a short time, and cannot be applied to the control of the primary control surface that requires high reliability.
By the way, in the prior art, the actuator model circuit mounted on the machine is required to be small, and it is difficult to realize an advanced model circuit. Therefore, there is a slight difference between the calculation result by the model circuit and the actual operation position. Even if an error occurs, it has been treated as unavoidable. Furthermore, even during normal flight, if a large load (for example, due to airflow turbulence or gusts) acts on the control surface, the actuator may not be able to follow the command input for a short time, and the actuator calculated based on the command input Since a relatively large difference occurs between the output position signal (S ₁ ) of the model circuit and the feedback signal (S ₂ ) indicating the actual operating position, it is necessary to prevent this from being determined as a failure. In addition, the actuator cannot be made very rigid in order to suppress the impact on the airframe side, and it is unavoidable that the errors of the signals S ₁ and S ₂ increase for a short time. ing.
[0009]
[Problems to be solved by the invention]
As described above, conventionally, since the rise of the failure detection signal is delayed by the time delay circuit and the failure determination time is lengthened to determine the presence / absence of the failure, there are the following problems.
When the control surface actuator is driven by a motor, it is conceivable that a current limiter is provided in the motor driver to prevent an excessive current exceeding a limit value from flowing in the motor so as not to deteriorate the performance of the motor. In such a case, the actuator may not be able to follow the command input due to the operation of the current limiter, which may take a little longer time. That is, when the deviation (e) has an absolute value equal to or greater than a predetermined detection threshold and the operating time of the current limiter is increased, a failure signal may reach a predetermined level and a situation may be erroneously determined as a failure. . Therefore, in order to avoid this, it is necessary to set the detection threshold to a high value, the sensitivity of failure detection becomes dull, and the time required for detection becomes long. Therefore, highly sensitive failure detection cannot be performed.
[0010]
Under these circumstances, it is assumed that the command value of the actuator does not continue to have a large difference from the actual position for a certain period of time, or an excessive external load (occurrence of the above-mentioned air turbulence or gust) occurs. A model is set on the assumption that a certain time or more will not be applied, and the detection time for failure determination threshold (e) is set to a large value. In short, the current situation is that the control system must be operated with a reduced detection sensitivity. Therefore, although it is convenient for a system that is not relatively important, it must be said that it is difficult to apply it to an advanced control system that requires certainty and requires extremely quick failure detection. Absent.
[0011]
[Means for Solving the Problems]
The present invention is an improvement of a fault detection apparatus that has higher fault detection sensitivity than the prior art and does not generate false signals.
That is, according to the present invention, in an electric control surface actuator, an actuator position is calculated from an actuator model having a second-order or third-order approximate transfer function, for example, based on a conventional calculation method of control characteristics. This is a control device that detects a failure by comparing the operating position of an actuator (actual machine). The improvement of the present invention resides in that a failure signal is generated only when the current limiter value of the motor driver is in the non-operating region when the failure is detected.
[0012]
Specifically, the position calculated by the actuator model is compared with the actual actuator operating position measured by the feedback sensor, the absolute value of the deviation exceeds a predetermined threshold, and the motor driver is built in the motor driver. If the current value of the current limiter exceeds a non-operating region of the current limiter, that is, a normal current value range, the control device is capable of detecting a failure and outputs a failure signal after a certain time delay.
[0013]
According to the present invention, a failure signal is not erroneously issued, and whether it is normal or failure is quick, so that it can be used for controlling the primary and control surfaces.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
The present invention is a control device for an electric control surface actuator, and an outline of this system is shown in FIGS.
The actuator (actual machine) has its operating position changed by a circuit comprising a forward circuit 27 comprising a motor driver 22, a motor 23 and a speed reducer 24, and a feedback circuit 28 comprising a feedback sensor 25 and a demodulator 26. It is basically controlled by the deviation signal of the adder 21 so that
[0015]
However, if the load from the outside is large, the actuator cannot immediately follow the command, and it may be mistaken that a failure has occurred. In the present invention, a control device that simply determines whether a failure is normal (a state in which the actuator position can be restored to a command value within a predetermined time), and outputs a failure signal if necessary. A control system having a function of avoiding generation of a signal.
[0016]
In the present invention, an actuator model 11 having a transfer function having the same control characteristics as the actual actuator is assumed, and the actuator position signal 12 of this model is compared with the signal 13 transmitted by the feedback sensor 25 of the actual actuator. Is used to determine a failure and, if necessary, to issue a failure signal.
[0017]
The model actuator signal 12 and the actual actuator position signal 13 are compared by an adder 30. The absolute value 16 of the difference exceeds a predetermined threshold 17, and the absolute value 19 of the current signal 15 of the current limiter 34 is the current. In the non-operating area 18 of the limiter, the fault signal 10 is output after a certain time delay 33 is applied.
[0018]
A feature of the present invention is that a failure is not detected within a current value range in which the current limiter operates normally. In the present invention, the AND circuit 35 determines the signals of the circuit for comparing the actuator position signals of the model and the actual machine and the current limiter circuit 29 to avoid malfunction.
FIG. 3 schematically shows the relationship of the threshold value of the current value of the current limiter.
[0019]
A range in which the current limiter operates (upper limit value and lower limit value) is set, and failure detection is performed based on the actuator model when outside this range. Here, the upper limit value at which the current limiter operates is selected as a value at which the transistors constituting the circuit are not thermally damaged due to an overcurrent to the motor driver, and the lower limit value is a current value corresponding to the maximum torque of the motor ( (Corresponding to the maximum torque required for ACT) can be selected.
[0020]
FIG. 2 is another embodiment of the present invention. Although the control system shown in FIG. 1 functions sufficiently, if the input or feedback signal system in the front stage of the motor driver is hard-over (output saturation), the control system of the present invention is within the current limiter operating range. The failure is not determined. Therefore, it is possible to detect a failure by providing an adder in front of the motor driver and providing a determination circuit for detecting hard over. In addition, an adder can be provided in the feedback system to determine a failure.
[0021]
The control system shown in FIG. 2 has a function that can detect an abnormality (failure) of the actual actuator by the feedback sensor 25 and can check a risk (failure) that occurs during the operation of the current limiter. It is much better than the control system.
[0022]
【The invention's effect】
The control device of the present invention performs detection of failure by comparing the actual machine with the model in consideration of the state even if the control surface command is input in steps or the actuator is overloaded, so the detection threshold and detection required There is an advantage that the time can be set in a narrower range (higher sensitivity) than the conventional model. Furthermore, since the control device of the present invention has no false detection and the time for notifying a failure (failure detection time) is detected, the reliability and safety are improved over the conventional system.
[0023]
Since the control device is improved in this way, basically, it can be applied as an electric control surface actuator for aircraft if the number of actuators requires one actuator per control surface.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a failure detection system of the present invention.
FIG. 2 is a block diagram showing another embodiment of the failure detection system according to the present invention.
FIG. 3 is an explanatory diagram of a current value threshold of a current limiter which is a component of the control device of the present invention.
FIG. 4 is a configuration diagram showing an example of a conventional failure detection system.
[Explanation of symbols]
10 Fault signal 11 Actuator model 12 Model actuator position signal 13 Actual machine actuator position signal 15 Current limiter current signal 16 Deviation signal 17 Detection threshold 18 Current limiter non-operation area 21 Adder 22 Motor driver 23 Motor 25 Feedback sensor 33 Time Delay 34 Current limiter

Claims (2)

An actuator whose operating position is changed by a motor and a reducer;
A feedback circuit for detecting an actual operating position of the actuator and outputting a feedback signal indicating the actual operating position;
An adder that adds the feedback signal and a command value signal indicating a target position to output a deviation signal corresponding to the difference between the two signals, and adjusts the operating position of the actuator according to the deviation signal from the adder. A forward-facing circuit including the motor to obtain;
A motor driver for driving the motor and a current limiter for controlling the current of the motor;
A control system for a control surface actuator of an aircraft or the like equipped with
An arithmetic circuit that calculates an approximate actuator position in an actuator model by performing an approximate calculation from the command value based on control characteristics of the actuator, the forward circuit, and the feedback circuit;
When the actuator actual operation position of the actuator and the approximate actuator calculation position are compared, and the difference in position exceeds a predetermined threshold,
A determination means for determining whether or not the current value of the current limiter of the motor driver is in a non-operational area; and a failure signal output means for indicating that a failure has occurred in the non-operational area; If the current value of the limiter of the motor driver is in the operating range, an actuator control device comprising the determination means and the failure detection means that can operate the determination means so as not to output a failure signal. The control device according to claim 1,
An actuator control device comprising a failure detection circuit including a new adder and / or a feedback detection failure detection circuit in front of a motor driver.

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