RU2263943C2 - Cybernetic microprocessor digital system - Google Patents

Abstract

FIELD: automatic control.

SUBSTANCE: system has digital control device with processor, digital control panel, control subject with direct current electric engines, digital angle indicators, digital control panel and digital power amplifier. Digital control device with quantizing period T gathers information from digital control panels, calculates de-synchronization and generates controlling digital signals, received via digital interface at digital power amplifier.

EFFECT: higher precision.

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Description

The invention relates to the field of technical cybernetics, in particular to microprocessor-based digital systems for automatic control of objects with direct current electric drives, and can be used mainly in control systems for optoelectronic surveillance systems.

Microprocessor-based digital systems for automatic control of objects with direct current electric drives are widely known in the technical and patent literature.

The monograph “Microprocessor-based automatic control systems” is known under the general editorship of V. A. Besekersky, Leningrad, “Mechanical Engineering”, 1988, where the basic principles of creation and the typical structures of digital automatic control systems (ACS) based on microprocessor technology are presented. The structural diagrams of such microprocessor control systems include a digital control device (DAC), a control object (DU), actuators (DUT), analog-to-digital converters (ADCs), digital-to-analog converters (DACs) and sources of input analog signals, which are also converted using ADC of a digital control device.

Such schemes have potentially high accuracy characteristics due to the use of microprocessor technology.

Their disadvantages are, firstly, the presence of analog-to-digital (ADC) and digital-to-analog (DAC) converters operating at low currents up to 1 mA and low DC voltages. While DC motors with anchor control require relatively high voltages with currents of up to 10A or more, therefore, the input or output voltages of the ADC and DAC must be amplified using multistage DC amplifiers with a large gain.

In addition, as a rule, DAC and ADC converters are structurally placed in a digital control device (DAC) and the converted signals are fed to them via long wires, being influenced by interference from power circuits, while the input and output analog signals usually contain random noises, which, as a result of amplification, are sources of digital system error. Quantization noise and “zero drift” of DC amplifiers of the DAC and ADC are added to them.

Secondly, the DC power amplifier has a low efficiency, which leads to increased heat generation and violation of the thermal regime of information devices (TV, thermal imager), which are usually located in closed structural volumes.

Thirdly, these microprocessor systems are monofunctional, while the management of optoelectronic survey systems requires the expansion of functionality by cybernation of digital self-propelled guns with multi-mode control with a single hardware implementation.

From the practice of developing and operating optical-electronic survey systems, it is known that observation is carried out in various modes: in a general panorama view, the optical line of sight moves at an average speed; when transferring the line of sight, maximum speed is required; when detecting and recognizing an object of observation, a very slow and smooth speed of movement is usually required.

Moreover, various discrete automatic control systems are known: pulse systems with amplitude modulation, systems with pulse-width modulation, relay systems and digital.

Analog self-propelled guns do not provide smooth movement of an object with very slow movement. Overcoming dry friction in the gearbox and other mechanical mates occurs unevenly, with some jerks, which complicates the process of observation and recognition.

Impulse systems provide at low speed a smooth movement of the line of sight with uniform overcoming of dry friction. However, pulsed systems have reduced overall performance, which is their drawback.

Systems with pulse-width modulation are more economical in energy consumption, cause minimal heat generation, however, when working in the zero region, the control signals become very short, and the control process is ineffective.

Relay systems provide maximum impact on the control object if necessary, rapid movements. Structurally, relay systems are the simplest, but the dynamics of the control mode are very difficult.

The listed discrete systems have various hardware implementation diagrammatically and structurally. Therefore, the possibility of their aggregation to ensure functioning in various modes of automatic control of the control object is excluded.

All this leads to the aggregate significant limitation of the potentially high accuracy of the digital system, complicates the structure and hardware implementation, reduces the operational reliability of the survey systems as a whole.

The closest in technical essence is the "Servo block" on the application of PCT (WO) No. 84/03572, MKI G 05 D 3/12, H 02 P 5/34, publ. 09/13/84, prior. 03/04/83 (IP), which allows the use of common hardware for various control modes by changing the program that controls the process in accordance with the specified control mode.

This ACS contains a central control unit with a processor, an op amp with a direct current electric drive, a digital angle sensor, a control panel, a relay power amplifier, an ADC, a counter, a timer, and control software.

The processor in the central control unit reads various control programs from the storage device according to commands from the interface circuit and prepares control commands for the relay power amplifier using the input signal of the armature current from the analog-to-digital converter and the input signal of the angle of rotation from the counter.

The command to control the power amplifier through the input-output port is sent to the timer and controls the power amplifier. In this way, the current of the electric drive is changed and thereby the operating mode of the electric drive with the op-amp is determined.

This technical solution is chosen as a prototype and uses the principle of multi-mode control provided by software using common hardware.

The disadvantages of the prototype include the content of an analog-to-digital converter (ADC) and the imperfection of the control mode of the electric drive due to the use of a relay power amplifier by changing the current of the armature circuit, which gives low control accuracy.

The claimed invention is directed to solving a technical problem in the theory and practice of automatic control for creating a cybernetic microprocessor digital system with a multifunctional control mode.

The claimed technical solution is a cybernetic microprocessor digital system containing a digital control device, a control object with a DC electric drive, digital angle sensors, a digital control panel and a digital power amplifier, while the digital power amplifier contains an input register, the outputs of which are connected in parallel code to two buffer registers, each of which is connected to amplifiers-converters of voltage level with load resistors with binary weight ohms connected to a summing large-scale resistor connected to a high potential of the power source, forming two voltage dividers, the output voltages of which are connected to a transistor bridge containing an even number of pairs of transistors, one group of which is included in the emitter follower mode, and the other group of transistors in the key mode.

Such a cybernetic digital system has direct microprocessor control of DC electric drives and provides all of the listed types of operating modes: quasi-continuous, pulse with amplitude modulation, pulse with pulse-width modulation and relay with a single circuit and structural hardware implementation, while the use of DAC and ADC is excluded.

The exception of the DAC and ADC in conjunction with DC amplifiers is possible thanks to the applied digital power amplifier, which implements their functions and directly controls the digital signals of the microprocessor, ensuring the formation of all types of control signals for DC drives: digital, pulse and relay. In this case, the amplification and formation of all types of control signals occurs directly in the digital power amplifier, but already in the field of high voltages and strong currents, there are many large levels of noise and interference.

Pre-amplification occurs in the key mode using high-current multi-bit switches, the outputs of which are connected to discharge resistors with binary weight, which together with a large-scale resistor form a discretely controlled voltage divider.

The proposed cybernetic digital system is illustrated by the structural diagrams presented in figure 1-2.

Figure 1 presents the structural diagram of a cybernetic microprocessor digital system.

Figure 2 presents the functional structural diagram of a digital power amplifier.

Cybernetic microprocessor digital system operates as follows.

A digital control device (CCU) (Fig. 1) with a quantization period of time T collects digital information from a digital control panel (PCC) and digital angle sensors (CDU), calculates the mismatches and, in accordance with the received data, generates control digital signals Ni, Nj, Nn.

The generated control digital signals arrive with time division into the corresponding digital power amplifiers (UMTSi, UMTSj, UMTSn) via a digital interface in serial or parallel code, where they are briefly fixed on the input register RG1 (Fig.2) and then for the period T period - in one from the buffer registers RG2 or RG3, depending on the sign of the signal arriving, according to Input 2 or Input 3.

Next, the digital signals from the buffer registers are sent in parallel code to the corresponding two groups of 169AA1 type microcircuit keys, the outputs of which are connected with binary weight resistors, which together with the large-scale resistors R0 and R10 form two voltage dividers.

The output voltage of the dividers is supplied to the base of the transistors VT1 and VT2 of the bridge, in the diagonal of which a DC drive is connected. The originality of the transistor bridge, in contrast to the known ones, lies in the fact that two transistors VT1 and VT2 are included in the emitter follower mode, and the other two transistors VT3 and VT4 operate in key mode. The shoulders of the bridge work so that one pair of transistors, for example VT1 and VT4, is in active mode, i.e. in the open state, and conduct current through the electric drive, and the second pair of transistors VT2 and VT3 are in a passive state, i.e. closed.

When the polarity of the control digital signal is changed, the transistors change their state to the opposite, and at the same time the electric drive is reversed. Thanks to this scheme of a digital power amplifier, the transistor bridge is fed with unipolar voltage instead of bipolar. Moreover, the nature of the control of the electric drive refers to a quasilinear form.

With pulse control of the electric drive, the process occurs similarly to the above, while amplitude modulation is carried out by changing the value of the control digital signal with a constant duration of its exposure τ <Т.

The duration of exposure to a digital signal is elementarily implemented by a microprocessor by replacing at the end of τ with a zero digital signal.

Pulse control with pulse-width modulation is implemented at a constant digital signal, and the duration of its exposure is controlled by varying the value of τ by software.

The relay mode can be modified by stepwise selection of digital signals during acceleration and shutdown of the motor.

Thus, it follows from the foregoing that the control modes are implemented by very simple microprocessor software.

Claims (1)

A cyber microprocessor digital automatic control system containing a digital control device with a processor that collects digital information from a digital control panel and digital angle sensors, generating digital control signals that are transmitted via a digital interface to the corresponding digital power amplifiers, while the digital power amplifier contains input register, where control digital signals are momentarily fixed, the outputs of which are connected to two buffer p to the registers, in one of which the control digital signals are briefly fixed depending on the sign of the signal, each of the buffer registers is connected to the key groups of the corresponding voltage level amplifiers-converters with load discharge resistors with binary weight, which together with summing scale resistors connected to a high potential unipolar power supply of the transistor bridge, two voltage dividers, the outputs of which are connected to the transistor bridge, in the diagonal of which The DC motor of the control object is turned on, while two bridge transistors are included in the emitter follower mode, and the other two bridge transistors operate in key mode, and the DC motor reverses when the polarity of the control digital signal is reversed.

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