JPH07104769A - Active controller - Google Patents

Abstract

PURPOSE:To prevent the active control abnormality caused by a bad environ ment by constituting the abnormality detection while executing the active control and the processing of the countermeasure with hardware but not software in an active controller. CONSTITUTION:This device is provided so as to constitute an abnormality detection means detecting the fact that the active control becomes an abnormal state and outputting an abnormality signal and an output interruption means receiving the abnormality signal from the abnormality detection means and interrupting an output of an active control signal with the hardware. To put it concretely, the abnormality is detected by a mean voltage take-out device 14 obtaining the mean voltage value of the active control signal converted into an analog amount by rectification and smoothing, a comparator 16 comparing the mean voltage value with a prescribed DC voltage from a prescribed voltage generator 15 and a prescribed time controller 17 outputting the abnormality signal by judging it to it be in an abnormal state when the state is continued for a prescribed time after it is judged that the mean voltage value is the prescribed voltage value or above, is compared and decided by the comparator 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active control device for suppressing phenomena such as noise and vibration by active control, and is applied to, for example, noise reduction in the interior of a car or an aircraft.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. H5-1993 has been proposed as a countermeasure against an abnormality in an active control device.
There is a technology of Japanese Patent No. 27780. In this conventional example, an abnormality is detected by comparing the evaluation function corresponding to the interference error signal and the number of changes in the sign of the gradient of the filter coefficient of the adaptive filter with a preset value, and at the time of abnormality, the sound emission of the control sound is calculated. It is characterized by having means for stopping at the instruction of the control device (in this case, a microprocessor). And the detection of abnormality is by software inside the arithmetic and control unit,
Furthermore, software for dealing with abnormalities is also performed by software inside the arithmetic and control unit, and the hardware configuration is as shown in FIG.
It is as 1.

In FIG. 11, reference numeral 1 is a sensor microphone for catching noise from a noise source, and 2 is for detecting an error (residual noise) that occurs after the canceling action due to the interference of control sound with respect to the noise. It is an error microphone. The output of the sensor microphone 1 and the output of the error microphone 2 are applied to A / D converters 5 and 6 through analog amplifiers 3 and 4, respectively. The analog amplifiers 3 and 4 include filters. A
The outputs of the D / D converters 5 and 6 are microcomputers or D
The arithmetic processing is performed by the arithmetic control device 7 composed of SP. The arithmetic and control unit 7 includes an adaptive digital filter and means for adaptively updating the filter coefficient. The active control signal output from the arithmetic and control unit 7 is D /
After being converted into an analog quantity by the A converter 8, the signal is supplied to the signal breaker 9.

The output of the signal breaker 9 is amplified by an analog amplifier 10 including a filter and then excites the speaker 11. The output (control sound) of the speaker 11 at the control sound output unit 12 acts on the noise so as to cancel the noise from the noise source. 13 is an A / D converter 5, 6 or D /
A sampling clock is given to the A converter 8 and
This is a sampling clock generator that gives an operation clock to the arithmetic and control unit 7 and controls the processing timing of the entire system.

[0005]

However, the above-mentioned conventional technique is premised on that the arithmetic and control unit 7 is executing the predetermined processing of the normal active control program. That is, even if the filter coefficient is continuously updated by the normal adaptive digital filter adaptive algorithm by the normal predetermined process, if the adaptive coefficient diverges due to some factor including disturbance, the abnormality is detected. As a predetermined abnormality countermeasure process, a command is issued to the means for controlling the cutoff of the emission of the control sound to cut off the control sound.

Therefore, if the program does not perform normal processing, an abnormal state cannot be detected and the control sound cannot be emitted. Therefore, there is a possibility that the abnormal control sound is emitted. There is enough. In such an abnormal situation,
Active noise reduction control of noise is sufficient to increase noise, but active vibration control of vibration may cause human life or increase disasters in some cases. For example, during active control, the active control device receives a sudden big shock, sudden power supply abnormality is observed, lightning surge, static electricity, strong electric field / strong magnetic field environment, high temperature / high humidity environment, temporary Various bad environments such as freezing and water leakage are assumed. After that, when the normal environmental condition is restored and active control is continuously performed, the processing performance of software is weaker than that of hardware. Even if the hardware returns to normal, the software cannot return from the abnormal state. It is difficult (see FIG. 12).

Further, when the adaptive digital filter and the adaptive coefficient updating algorithm are used in the method of generating the active control signal in the arithmetic and control unit, even if the software is not directly affected by the abnormal environment, When voice or vibration outside the control range due to such environmental changes enters from each signal input means such as sensor microphone or error microphone for a moment, the internal adaptation coefficient obediently learns the signal of abnormal environment and the adaptation coefficient itself It can diverge and eventually continue to produce runaway output. Therefore, software countermeasures against abnormalities in active control are incomplete. An object of the present invention is not to perform anomaly detection during active control execution and processing of countermeasures thereof by a command from an arithmetic and control unit, but to perform an active control unit configured by hardware that is resistant to a bad environment. To provide.

[0008]

According to the present invention, a phenomenon such as noise or vibration which is an object of active control is detected, and an active control signal corresponding to the detection is generated by software by the arithmetic control means and output. In an active control device that suppresses a phenomenon, an abnormality detection unit that detects an abnormal state of active control and outputs an abnormality signal, and an active control signal output in response to an abnormality signal from the abnormality detection unit The output cutoff means for cutting off the power supply is constituted by hardware.

In this case, the abnormality detecting means includes an averaging means for obtaining an average voltage value of the output active control signal, a comparing means for comparing the average voltage value from the averaging means with a predetermined value, and the comparing means. If the average voltage value is compared and determined to be greater than or equal to a predetermined value, then that state continues for a predetermined time or until the sampling clock that controls the processing timing of the entire apparatus is counted by a predetermined number of pulses. It also includes time management means for outputting an abnormal signal as an abnormal state.

Further, in the present invention, the abnormality detecting means is
Comparing means for comparing a clock having a stable cycle in a normal state output from the arithmetic control means with a predetermined cycle; and after comparing and judging by the comparing means that the clock cycle does not match the predetermined cycle, And a time management means for outputting an abnormal signal as an abnormal state if the state continues for a predetermined time or until the sampling clock that controls the processing timing of the entire apparatus is counted for a predetermined number of pulses. .

Further, the abnormality detecting means is a temperature detecting means for detecting the surface temperature of the arithmetic control means or its associated peripheral devices, and the temperature detected by the temperature detecting means is within a predetermined temperature range. Sampling that controls whether the temperature detected by this comparison means is out of a predetermined temperature range for a predetermined time or the processing timing of the entire device. When the clock is continued until a predetermined number of pulses are counted, it is determined that the clock is in an abnormal state, and a time management means for outputting an abnormal signal is included.

Further, the abnormality detecting means includes an averaging means for obtaining an average voltage value of the output active control signal, a differentiating means for obtaining a differential value of the average voltage value from the averaging means in a unit time, and the differentiating means. Comparing means for comparing the differential value from the predetermined value with a predetermined value, the state is a predetermined time after the comparison value is compared and determined by the comparing means to be a predetermined value or more,
Alternatively, it includes a time management means for outputting an abnormal signal indicating that the sampling clock, which controls the processing timing of the entire apparatus, is in an abnormal state when it is continued until a predetermined number of pulses are counted.

The abnormality detecting means compares and determines whether or not the absolute value of the active control signal output as a digital value from the arithmetic control means is the maximum value that can be handled by the D / A converter in the subsequent stage. And the comparison means and the comparison means determines that the absolute value of the active control signal is the maximum value for a predetermined time, or the sampling clock for controlling the processing timing of the entire device has a predetermined number of pulses. It includes a time management means for outputting an abnormal signal as an abnormal state if continued until the counting.

Further, the arithmetic control means comprises an adaptive digital filter and coefficient updating means for adaptively updating the filter coefficient thereof. The coefficient updating means receives the abnormality signal from the abnormality detecting means and receives the filter coefficient. The update process is stopped, and the filter coefficient immediately before the stop is held as the initial value when the update process is restarted.

[0015]

For example, the active control signal for suppressing the phenomenon such as noise is generated by the arithmetic control means by software. However, the abnormality detection of the active control is performed by the abnormality detection means constituted by hardware, and the cutoff means cuts off the active control signal based on the signal output by the abnormality detection means. Therefore, even if an abnormal operation of software occurs due to various internal and external factors during active control by the active control device, the abnormal state is detected by the hardware circuit, and the hardware that does not depend on software is also taken for the countermeasure. Since it is performed by the circuit of, it is less likely to be affected by external noise, shock, bad environment, and other factors, and factors that prevent self-control.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The same parts as those of the conventional one are designated by the same reference numerals and the description thereof will be omitted. In the present embodiment, all of the detection of abnormality during active control execution and its countermeasure are carried out by a circuit of hardware having a higher processing performance than software.

First, FIG. 1 shows the first embodiment of the present invention. The average voltage of the active control signal from the arithmetic and control unit 7 converted into an analog quantity by the D / A converter 8 is used to detect abnormality during active control execution. An average voltage extractor 14 which obtains a DC value by rectifying and smoothing, and an average voltage value of the average voltage extractor 1
5 is compared with a predetermined DC voltage value, and the state is kept for a predetermined time (for example, CR
A predetermined time management unit 1 which outputs an abnormal signal as an abnormal state when continued for a time determined by a time constant or the like) 1
It is designed to be performed with 7. When an abnormal signal is output from the controller 17 for a predetermined time, the signal breaker 9 cuts off the output of the active control signal to the speaker 11 by means of an NPN transistor, a CMOS analog switch, a relay or the like. .

In this case, for example, when the arithmetic and control unit 7 causes a software abnormality in an adverse environment, which causes an abnormally large active control signal from the arithmetic and control unit 7, for example. Is the comparator 1 that the average voltage value of the active control signal becomes equal to or higher than a predetermined voltage value
The abnormality is detected by comparing and judging in 6 and confirming that the state has continued for a predetermined time by the manager 17 for a predetermined time. As a result, the output of the active control signal is cut off by the signal breaker 9, and the abnormal control sound emission due to the abnormal operation of the software is stopped.

In FIG. 1, the CR time constant is used to manage the continuation for a predetermined time. However, as shown in FIG. 2, the number of pulses of the sampling clock from the sampling clock generator 13 is logically counted and predetermined. It may be possible to manage whether or not it is continued until a few are counted. Further, in the case where the arithmetic and control unit 7 uses the adaptive digital filter 18 and the coefficient updating means 19 for adaptively updating the filter coefficient by the adaptive coefficient updating algorithm in the method of generating the active control signal, The filter coefficient update process may be stopped by an abnormal signal (dotted line arrow in FIG. 1) from the manager 17 for a predetermined time, and the filter coefficient immediately before the stop may be held as an initial value when the update process is restarted. (The same applies to each example described later). In this way, even if the abnormal state is detected and the output of the active control signal is cut off, the arithmetic and control unit 7 is temporarily operated.
If the software is normal, an abnormal state occurs temporarily, but if the abnormal state is no longer detected, normal active control before the abnormality can be resumed immediately.

FIG. 3 shows a second embodiment of the present invention, in which the arithmetic and control unit 7 is processed in parallel with a job originally processed by the arithmetic and control unit 7.
A clock having a stable cycle is output from the arithmetic and control unit 7 itself only when the normal operation is performed, and abnormality detection during active control is detected by the predetermined cycle from the predetermined cycle generator 20. And a predetermined time management unit 17 that manages the output of the comparator 21.
It was designed to be performed with and. By doing so, for example, when the software inside the arithmetic and control unit 7 runs away and an abnormality occurs, the output of the clock from the arithmetic and control unit 7 is interrupted or its cycle becomes random, so that the comparator The abnormality is detected by comparing and determining in 21 that it does not match the predetermined cycle and confirming that the state has continued for the predetermined time by the predetermined time management unit 17.

Although the clock cycle from the arithmetic and control unit 7 is compared with the output cycle from the predetermined cycle generator 20 by the comparator 21, the cycle is monitored by using a PLL circuit or the like. Is also good. Note that FIG. 4 shows a case where the predetermined time management unit 17 manages whether or not the sampling clock from the sampling clock generator 13 continues until a predetermined number of pulses are counted.

Next, FIG. 5 shows a third embodiment of the present invention, in which a temperature sensor 22 such as a thermistor is mounted on the surface of a device such as the arithmetic and control unit 7 or a controller associated therewith to monitor the surface temperature due to heat generation as needed. In this way, the abnormality detection during active control is handled by the output voltage from the temperature sensor 22 via the voltage amplifier 23 being higher than the voltage value corresponding to the upper limit temperature from the predetermined voltage generator 24 or corresponding to the lower limit temperature. This is performed by a comparator 25 such as a window comparator that determines whether or not the voltage value is lower than the predetermined voltage value, and the predetermined time management device 17 that manages the output of the comparator 25.

In this way, the comparator detects that the surface temperature of the arithmetic and control unit 7 detected by the temperature sensor 22 is outside the temperature range determined by the output voltage value from the predetermined voltage generator 24, for example, higher than the upper limit temperature. When it is compared and determined in 25 and is confirmed by the manager 17 for a predetermined time that the state has continued for a predetermined time, it is detected that the arithmetic and control unit 7 is in an abnormal control state due to abnormal heat generation.
Note that FIG. 6 shows a case where the predetermined time management unit 17 manages whether or not the sampling clock from the sampling clock generator 13 continues until a predetermined number of pulses are counted.

FIG. 7 shows a fourth embodiment of the present invention, in which abnormality detection during execution of active control is performed by obtaining the differential value per unit time of the average voltage value from the average voltage extractor 14 in the first embodiment. The differentiator 26 and a comparator 28 such as a window comparator which determines whether the differential value is higher than the upper limit value or lower than the lower limit value from the predetermined value generator 27.
And the output of the comparator 28 is controlled by the predetermined time management unit 17 described above. In this case, the abnormality is detected from the change in the output of the active control signal. Incidentally, FIG. 8 shows a predetermined time management unit 17
2 shows a case where it is controlled whether or not the sampling clock from the sampling clock generator 13 is continued until a predetermined number of pulses are counted.

Further, FIG. 9 shows a fifth embodiment, in which the absolute value of the active control signal output from the arithmetic and control unit 7 in a digital amount is used to detect the abnormality during the active control.
The comparison is performed by the comparison unit that determines whether or not the maximum value that can be handled by the converter 8 (that is, the signal that is in the saturated state) and the predetermined time management unit 17 that manages the output of the comparison unit 29. It was done like this. Here, the comparison unit 29
Are exclusive OR circuits 30a to 30h, an abnormality determination data generator 31 for giving reference data (a positive or negative maximum value that can be handled by the D / A converter 8) for abnormality determination, and an OR circuit 32. It consists of

In this way, when the exclusive OR circuits 30a to 30h determine that the digital control signal and all the bits of the reference data are logically identical, the output of the OR circuit 32 becomes L. It becomes a level state. When the controller 17 confirms that the state has continued for a predetermined time, the output abnormality of the arithmetic and control unit 7 is detected. Note that FIG. 10 shows a case where the predetermined time management unit 17 manages whether or not the sampling clock from the sampling clock generator 13 continues until a predetermined number of pulses are counted.

As described above, in the present embodiment, the dependence on software is supplied by supplying the abnormal signal detected by the hardware configuration to the arithmetic and control unit irrespective of whether or not the arithmetic and control unit causes the software to runaway due to the bad environment. Sex can be completely eliminated. Further, in each embodiment, in detecting the abnormality of the active control, whether to judge from the state or change of the output of the active control signal, to see the state of output of the signal for grasping the internal state of the arithmetic and control unit, or to objectively measure the heat generation However, by performing a plurality of combinations of the respective embodiments depending on the application, it is possible to more safely and accurately respond to an abnormal condition. In other words, it is possible to use a method in which various kinds of abnormality detecting means are provided and a logical sum or a logical product of the respective abnormality detection signals is selectively used to generate a final abnormality detection signal. In each of the embodiments, a microphone is used to detect noise (including residual noise), but if the noise source is, for example, the engine part of a car, a vibration pickup or encoder for acquiring its vibration or rotation speed. May be used, and any active action means that actively interferes with a phenomenon is not limited to the speaker.

[0028]

As described above, according to the active control device of the present invention, the active control signal is generated by the arithmetic and control unit by software, but the abnormality detection of the active control and the corresponding processing are completely dependent on the software. It will be achieved with hardware that does not include external noise, shock,
It is possible to realize a control system that is not easily affected by obstacles such as a bad environment or factors that prevent self-control. Furthermore, since there is no dependence on software, it does not matter what kind of digital filter is used in the internal processing of the arithmetic and control unit, that is, all elements such as configuration, method, number of taps, convergence algorithm, convergence coefficient, adaptation, etc. It is possible to perform the abnormality detection and the corresponding processing regardless of the above.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing another configuration example.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing another configuration example.

FIG. 5 is a block diagram showing a third embodiment of the present invention.

FIG. 6 is a block diagram showing another configuration example.

FIG. 7 is a block diagram showing a fourth embodiment of the present invention.

FIG. 8 is a block diagram showing another configuration example.

FIG. 9 is a block diagram showing a fifth embodiment of the present invention.

FIG. 10 is a block diagram showing another configuration example.

FIG. 11 is a block diagram showing a conventional example.

FIG. 12 is a diagram showing the influence of adverse environment on software and hardware and its recovery.

[Explanation of symbols]

 1 Sensor Microphone 2 Error Microphone 7 Arithmetic Control Device 8 D / A Converter 9 Signal Breaker 13 Sampling Clock Generator 14 Average Voltage Extractor 15, 24 Predetermined Voltage Generator 16, 21, 25, 28 Comparator 17 Predetermined Time Management Generator 20 Predetermined cycle generator 22 Temperature sensor 26 Time differentiator 27 Predetermined value generator 31 Abnormality judgment data generator

Claims (7)

[Claims] 1. An active control device for detecting a phenomenon, such as noise or vibration, which is an object of active control, and for generating an active control signal corresponding to the detection by software in an arithmetic control means and outputting it to suppress the phenomenon. In the above, an abnormality detection means for detecting that the active control is in an abnormal state and outputting an abnormality signal, and an output cutoff means for cutting off the output of the active control signal in response to the abnormality signal from the abnormality detection means are provided. An active control device characterized by being configured by hardware. 2. The abnormality detecting means includes an averaging means for obtaining an average voltage value of an active control signal to be output, a comparing means for comparing the average voltage value from the averaging means with a predetermined value, and the comparing means. It is abnormal if the average voltage value is compared and judged to be more than a predetermined value and that state continues for a predetermined time or until the sampling clock that controls the processing timing of the entire device is counted for a predetermined number of pulses. 2. The active control device according to claim 1, further comprising: a time management unit that outputs an abnormal signal in the abnormal state. 3. The abnormality detecting means compares a clock having a stable cycle in a normal state output from the arithmetic control means with a predetermined cycle, and the comparing means determines a predetermined clock cycle. An abnormal signal indicating that the state is abnormal if the state is continued for a predetermined time or until the sampling clock that controls the processing timing of the entire device is counted for a predetermined number of pulses after being compared and determined not to match the cycle. The active control device according to claim 1, further comprising: a time management unit that outputs 4. The temperature detection means for detecting the surface temperature of the arithmetic control means or its associated peripheral devices, and the temperature detected by the temperature detection means is within a predetermined temperature range. Sampling that controls whether the temperature detected by this comparison means is out of a predetermined temperature range for a predetermined time or the processing timing of the entire device. The time management means for outputting an abnormal signal indicating that the clock is in an abnormal state when the clock is continued until a predetermined number of pulses are counted.
The active control device according to. 5. The abnormality detecting means includes an averaging means for obtaining an average voltage value of an active control signal to be output, a differentiating means for obtaining a differential value of the average voltage value from the averaging means in a unit time, and the differentiating means. Comparing means for comparing the differential value from a predetermined value with a predetermined value, and after this comparison means determines that the differential value is greater than or equal to a predetermined value, that state governs a predetermined time or the processing timing of the entire apparatus. The active control device according to claim 1, further comprising: a time management unit that outputs an abnormal signal indicating that the sampling clock is in an abnormal state when the sampling clock is continued until a predetermined number of pulses are counted. . 6. The abnormality detection means compares and determines whether or not the absolute value of the active control signal output as a digital value from the arithmetic control means is the maximum value that can be handled by the D / A converter in the subsequent stage. And the comparison means and the comparison means determines that the absolute value of the active control signal is the maximum value for a predetermined time, or the sampling clock for controlling the processing timing of the entire device has a predetermined number of pulses. The active control device according to claim 1, further comprising: a time management unit that outputs an abnormal signal as an abnormal state when continued until it is counted. 7. The calculation control means includes an adaptive digital filter and coefficient updating means for adaptively updating the filter coefficient thereof, and the coefficient updating means receives the abnormal signal from the abnormality detecting means and receives the filter coefficient. 2. The active control device according to claim 1, wherein the update process of step 1 is stopped, and the filter coefficient immediately before the stop is held as an initial value when restarting the update process.