RU2798049C1 - Redudant digital automatic regulation system - Google Patents

Abstract

FIELD: redundant automatic control systems.

SUBSTANCE: technical result is achieved by introducing four identical channels in the centralized control device (CCD), connected according to the scheme providing “2 out of 3 plus 1” redundancy, and introducing a system for selecting a reliable control action in the computing devices of the control object, with each CCD channel containing a computing device, a scaling amplifier, an analog-to-digital converter and a serial interface transmitter via the LVDS bus, the transmitters of the CCD serial interface are connected to the receivers of each of the N channels of the control object of the automatic control system.

EFFECT: increase of reliability of calculation of the control signal with the possibility of scaling the number of channels of the control object.

1 cl, 3 dwg

Description

The invention relates to automatic control systems for computing devices and can be used in the development of digital redundant automatic control systems, for example, in the construction of a digital redundant automatic control system for energy-converting spacecraft (SC) equipment.

A four-channel control system is known (patent No. 2665252, IPC G06F 15/16, published on August 28, 2018), containing four control channels, each of which has information signal inputs, three main inputs and three main outputs for information exchange between adjacent channels, three backup inputs and three backup outputs for reserving failures in the operation of the main inputs-outputs of information exchange between control channels, inputs for receiving error signals of adjacent channels, outputs for transmitting error signals detected as a result of control signal majorization, the main and backup input-output for transmission telemetry of external equipment, each channel includes a computing device, the first output of which is connected to the main and backup transmitters of the serial interface, the second output to the first input of the majority element, which is a reserve for generating a control signal in its own channel, the third input-output to the first input - the output of the telemetry control unit, the fourth input to the fourth output of the error control unit, the fifth - n inputs of information signals connected to external outputs, a serial interface, which includes three main transmitters connected to external outputs, three backup transmitters connected to external outputs, three main receivers connected to the external outputs and inputs of the majority element, and three backup receivers connected to the external outputs and inputs of the majority element, a telemetry control unit that has an input-output connected to a computing device, the main and backup information channels connected to external outputs, the majority element, the first input of which is connected to the computing device, the second, third and fourth inputs are connected to serial interface receivers, the fifth output is connected to the eighth input of the error control unit, the sixth output is connected to the external output of the control signal, the error control unit, the first, second, third outputs of which are connected to external outputs, the fourth output is connected to the fourth input of the computing device, the fifth, sixth and seventh inputs to external outputs. Fault tolerance is achieved due to the ability of the system to function in case of failure of two channels while maintaining system operability, as well as the presence of redundant control signal exchange lines. The testability and autonomy of the system, in the event of a failure of one of the channels, is achieved due to the ability of the majority restoration of information according to the “2 out of 3” voting scheme between the computing units and the input-output units of the system channels without the involvement of external equipment.

The specified device is the closest in technical essence and taken as a prototype.

The disadvantages of this technical solution are a complex algorithm for controlling errors in the calculation of the control signal, which implies a large number of connections between channels and, as a result, a low speed of calculating the control signal and a significant complication of the control system with an increase in the number of channels of the control object, as well as the testability and autonomy of the system, in case of failure only one of the channels in the system.

For the claimed invention, the following essential features in common with the prototype have been identified: a digital redundant automatic control system contains: a digital control device, which includes four channels, each of which contains a computing device, a serial interface transmitter and a control object (OK), consisting of N independent channels.

The technical problem of the invention is to simplify the algorithm for controlling errors in the calculation of the control signal, to reduce the number of connections between channels, to simplify the control system with an increase in the number of channels of the control object, and to increase the testability and autonomy of the system.

The technical result consists in increasing the reliability and scalability of the automatic control system by introducing four identical channels in the centralized control device operating according to the "2 out of 3 plus 1" redundancy scheme and introducing a system for selecting a reliable value of the control action in the computing devices of the OK channels.

The technical problem is solved, and the technical result is achieved by the fact that in a digital redundant automatic control system, the output of the analog part of the OK, consisting of N channels, in each of the four channels of the digital control device (CCD) is connected to the input of the scaling amplifier, the output of the scaling amplifier is connected to the input an analog-to-digital converter (ADC), and the ADC output is connected to four inputs of the CCU computing device, the controller of the CCU computing device, based on the digitized feedback signal and a given reference value, calculates the control action for the OK channels, two outputs of the CCU computing device are connected to two transmitter inputs serial interface LVDS, the outputs of the serial interface transmitter of each of the four channels of the CCU are connected to the inputs of the serial interface receiver of each of the N OK channels, the outputs of the serial interface receiver are connected to the inputs of the computing device OK, the computing device OK calculates the CRC code for the values received from the serial interface receiver on the basis of which it selects 3 values used to select one reliable value using the median element. Based on the selected reliable value of the control action and the feedback signal coming from the ADC output of the analog part of the OK channel, the digital controllers of the OK computing devices calculate the control signals for the analog part of each of the N OK channels.

Fault tolerance is achieved due to the ability of the system to function in case of failure or failure of data transmission of two channels of the control center, while maintaining the system's operability.

Improving the controllability and autonomy of the system, in case of failure or failure of data transmission of two channels of the CCU, is achieved by the algorithm for rejecting one incorrect value and the median filtering of three values of the control action in the computing device of each OK channel.

The object of control refers to the elements of the system that are controlled by the CCM.

The invention is illustrated by diagrams:

- fig. 1 is a block diagram of a digital redundant automatic control system;

- fig. 2 - structural diagram of the channel TSUU;

- fig. 3 - block diagram of the OK channel.

Digital redundant automatic control system (Fig. 1) contains:

– four channels of the DCU (1), each of which contains the input of the feedback signal fed to the scaling amplifier (3), the output of the scaling amplifier (3.1) goes to the ADC (4), after which the digitized feedback value (2.1, 2.2, 2.3 , 2.4) is fed to a computing device based on a programmable logic integrated circuit (FPGA) (2), in which the digital code of the control action (2.5, 2.6) is calculated, entering the input of the LVDS transmitter (5), which ensures the transfer of the control action (5.1) to all channels are ok.

– N OK channels (6), each of which contains an LVDS serial interface receiver that receives control signals (8.1, 8.2, 8.3, 8.4) from four channels of the CCU. The LVDS serial interface receiver (8) transmits control signals to the inputs (7.1, 7.2) of the OK computing device based on the FPGA (7). The outputs of the computing devices of the OK channels issue control signals (7.3) to the analog parts of the OK channels (9).

The channel of the TCU system (Fig. 2) is a computing device based on the FPGA (2), the input feedback signal is connected to the scaling amplifier (3), the output of the scaling amplifier is connected to the ADC input (4), the digitized value of the feedback signal is fed to the FPGA (2), on the basis of which the control action is calculated for the OK channels coming from the FPGA output (2) to the output of the LVDS serial interface transmitter (5).

The OK channel (6) (Fig. 3) includes an FPGA-based computing device (7), four control inputs are connected to the LVDS serial interface receiver (8). In the FPGA, for the values received from the LVDS receiver, the CRC code (7.1) is calculated, after which 3 values (7.2) are selected, used in the median element (7.3). Based on the reliable value of the control action selected in the median element and the feedback signal coming from the ADC output of the analog part of the OK channel (9), the controller (7.4) calculates the signal that controls the analog part of the OK channel (9).

The blocks included in the redundant automatic control system perform the following main functions, described below.

The computing device (2) on the input signal from the ADC, generates a control action, providing the logic of the OK functioning. LVDS serial interface transmitters (5) and LVDS serial interface receivers (8) are designed to organize the exchange of control signals between the channels of the redundant digital control device and the OK channels (Fig. 1). The scaling amplifier (3) serves to match the input voltage with the ADC input (4). ADC (4) converts the analog signal coming from the scaling amplifier into a digital code.

The computing device (7) selects a reliable value of the control action from four values (8.1, 8.2, 8.3, 8.4) coming from four channels of the CCU, and calculates the control signal (7.3) by the analog part of the corresponding OK channel (9).

The claimed redundant automatic control system operates as follows:

To ensure the redundancy of the automatic control system, the digital control device is built from four parallel channels, which, together with the control action selection system in each OK channel, makes it possible to provide redundancy according to the “2 out of 3 plus 1” scheme. This means that the OC will work with a reliable control signal, even if at some stage of operation, from direct processing of the feedback signal to its transmission to the OC channels, a failure or failure occurs in two channels of the CCU or two data transmission channels. All TCUU and OK channels are powered from independent power sources, which eliminates the mutual influence of the TCUU and OK channels on each other.

The analog feedback signal (9.1), which is scaled and digitized, is fed to the input of all channels of the CCU. The digitized value of the feedback signal is used to form the control action for the OK channels.

Transfer of the control action from the channels of the CCU, which form the external loop of the automatic control system, is carried out using a serial interface with the physical level LVDS simultaneously to all channels of the OK. The control action is transmitted as a 16-bit data word and a CRC8 correction code. In each OK channel, the CRC code is first calculated to detect errors in data transmission and check the operability of the CCU channels. If the CRC code does not match in one of the received values, the received value is not taken into account for further operation. After calculating the CRC code, three values are sampled from the four received values of the control action, the obtained values are transferred to the median element, which builds these three values in ascending order and finds among them the control action that is the average of the three. The selected value is used to calculate the control signal for the analog part of the OK channel (9). In the event that one of the values received at the median element turns out to be faulty, it will not affect the output value of the median element.

Thus, this digital redundant automatic control system provides fault tolerance, testability and autonomy in the event of two failures or failures in the operation of the CCU channels or during the transfer of control action.

The claimed redundant control system can be implemented on the following elements: The computing device of the control channels can be implemented on microcontrollers of the STM32 type from STMicroelectronics, 1986BE1(8) or FPGAs of the Cyclone III - V type from Altera, 5578TC084 (5578TC094) from VZPP -WITH". The serial interface transmitter can be implemented on SN65LVDS050PW chips from Texas Instruments, ADN4665 from Analog Devices, 5560IN1T from Integral. The serial interface receiver can be implemented on SN65LVDS048APW chips from Texas Instruments, ADN4666 from Analog Devices, 5560IN2T from Integral. The ADC can be implemented on AD7490 microcircuits from Analog Devices, LTC1598 from Linear Technology.

The computing device of the receiver can be implemented on the FPGA of the Cyclone III - V type from the Altera company or 5578TC084 (5578TC094) from the VZPP-S company.

Claims (1)

A digital redundant automatic control system containing a digital control device (CCD), which includes four channels, each of which contains a scaling amplifier, a CCU computing device and a serial interface transmitter, characterized in that the scaling amplifier of each of the four channels of the digital control device is connected to feedback signal of the control object (OC), consisting of N channels, the output of the scaling amplifier is connected to the input of an analog-to-digital converter (ADC), and the output of the ADC is connected to the inputs of the computing device CCU, the controller of the computing device CCU based on the digitized feedback signal and the specified of the reference value calculates the control action for the OK channels, the outputs of the CCU computing device are connected to the inputs of the transmitter of the LVDS serial interface, the outputs of the serial interface transmitter of each of the four channels of the CCU are connected to the inputs of the serial interface receiver of each of the N channels of the OK, the outputs of the serial interface receiver are connected to the inputs of the computing device OK, the computing device OK for the values received from the receiver of the serial interface, calculates the CRC code, on the basis of which it selects 3 values used to select one valid value using the median element, based on the selected valid value of the control action and the feedback signal connection coming from the ADC output of the analog part of the OK channel, the digital controllers of the OK computing devices calculate the control signals for the analog part of each of the N OK channels.

Images