JPH03119401A - Controller - Google Patents

Abstract

PURPOSE:To suppress the influence of quantization error by providing a sensor which outputs the analog information in response to the action of a control subject, a phase compensation circuit which receives input of the analog information, and a digital signal process circuit which digitizes the output of a phase compensation circuit and controls the control subject. CONSTITUTION:A signal is inputted to a phase compensation circuit 2 from a sensor 1 which outputs the analog information in response to the action of a control subject. The signal received by the circuit 2 is digitized by an A/D converter 3 and this digitization output is processed by a digital signal process circuit 14 which contains no phase compensation means. Then a necessary control signal is outputted for control of a drive circuit 5. In such a constitution, quantization error produced at A/D conversion is not amplified by the phase compensation of a control loop. Thus it is possible to ensure the stable control with no influence of the quantization error.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device, and particularly to a control device having a function of performing phase compensation of a control loop including a digital signal processing circuit.

[Conventional technology]

Conventionally, a control circuit including a digital signal processing circuit such as a software servo or a digital servo is equipped with a sensor input for obtaining a control error, and converts the analog input value into a digital value using an analog-to-digital (A/D) converter. Generally, a desired control signal is formed by converting the signal into a signal and then performing digital signal processing. The configuration of such a control device is shown in FIG. In addition, Fig. 4 (A) - (
E) shows the frequency characteristics of the signals of each processing section.

The explanation will be given below in order. In FIG. 3, l is a sensor for obtaining a control error, 3 is an A/D converter that converts analog information from the sensor l into digital information, and 4 is an A/D converter that converts analog information from the sensor l into digital information.
is a digital signal processing circuit for calculating the obtained digital information and forming a control signal according to desired characteristics.

This control signal is supplied to the drive circuit 5, and the controlled object 6 is controlled to a desired control target.

-The transmission characteristics of Zarbolube for boat fishing can be expressed as shown in Figure 4 (A). Further, the disturbance in the control system has a frequency characteristic shown in FIG. 4(B).

The signal from the sensor l in FIG. 3 has the characteristics shown in FIG. 4(B). By passing this signal through the A/D converter 3 shown in FIG. 3, quantization errors are weighted out, and the characteristic after quantization becomes the characteristic shown in FIG. 4(C).

In the digital signal processing circuit 4, it is common to perform phase compensation with the characteristics shown in FIG. 4(D), which allows the control loop to operate stably and obtain desired control characteristics.

However, the output characteristics of the digital signal processing circuit described above are
As shown in Figure (E), the quantization error is amplified together with the control information due to phase compensation.

Therefore, in the conventional example described above, the quantization error is amplified together with the signal due to phase compensation, and the amplified quantization error has a problem that an adverse effect occurs. Furthermore, increasing the number of quantization bits to reduce quantization errors requires an expensive A/D converter, and also increases the number of processing bits of the digital signal processing circuit 4, requiring an increase in the scale of hardware or software. Ta.

Against this background, an object of the present invention is to provide a control device that can suppress the influence of quantization errors without increasing hardware or software.

[Means to solve the problem]

For this purpose, the control device of the present invention has the following features:
A sensor that outputs analog information according to the operation of a controlled object, a phase compensation circuit into which the analog information from the sensor is input, and a circuit for controlling the controlled object according to information obtained by digitizing the output of the phase compensation circuit. The configuration includes a digital signal processing circuit.

[Effect]

By configuring as described above, the quantization error that occurs when digitizing an analog quantity can be configured without going through the phase compensation circuit, and the quantization error can be amplified by the phase compensation circuit. Since there is no quantization error, it is possible to construct a control loop that is not affected by quantization errors.

〔Example〕

FIG. 1 is a diagram showing an example of a control device as an embodiment of the present invention, and FIG. 2 is a diagram showing the frequency characteristics of the signal in the numbered part of FIG. 1 is a sensor for obtaining a control error, 2 is a phase compensation circuit, 3 is an A/D converter, and 14 is a digital signal processing circuit.

Similar to the device shown in FIG. 3, the disturbance in the control system has the characteristics shown in FIG. 4(B), and the signal from the sensor l shown in FIG. 1 has the characteristics shown in FIG. 4(B). Next, assuming that the phase compensation circuit 2 has the characteristics shown in FIG. 4(D), the characteristics outputted through the phase compensator 2 will be the characteristics shown in FIG. 2(A). Furthermore, when the quantization error that occurs during digitization by the A/D converter 3 is added, a characteristic as shown in FIG. 2(B) is obtained.

As is clear from FIG. 2(B), the quantization error is not amplified even in the digital information after phase compensation. The output of the A/D converter 3 is processed by a digital signal processing circuit 4 having no phase compensation means, and a necessary control signal for controlling the drive circuit 5 is output. For example, controlled object 6
If it is a motor, it receives digital information of a level corresponding to a speed error and a phase error, and outputs a PWM drive signal, a digital value corresponding to a motor drive voltage, etc.

By configuring as described above, the quantization error generated during A/D conversion is not amplified by performing phase compensation of the control loop, and stable control that is not affected by the quantization error can be performed. can.

〔Effect of the invention〕

As explained above, according to the control device of the present invention, a control device that is not affected by quantization errors can be obtained without increasing the scale of hardware or software.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a control device as an embodiment of the present invention, FIGS. 2(A) and (B) are diagrams showing the signal characteristics of the numbered part in FIG. 1, and FIG. A diagram showing an example of the configuration of the control device, FIG. 4 (A
) to (E) are diagrams showing the signal characteristics of the numbered part in the third figure. 1 is a sensor, 2 is a phase compensation circuit, 3 is an A/D converter, 4
, 14 is a digital signal processing circuit, 5 is a drive circuit, and 6 is a controlled object. n Aki - In the rough part -

Claims (2)

[Claims] (1) A control system that performs phase compensation of a control loop,
A sensor that outputs analog information according to the operation of a controlled object, a phase compensation circuit into which the analog information from the sensor is input, and a circuit for controlling the controlled object according to information obtained by digitizing the output of the phase compensation circuit. A control device that includes a digital signal processing circuit. (2) The control device according to claim (1), wherein a part of the processing in the digital signal processing circuit is performed by software.