CN103838257A - Telescope rack control system - Google Patents

Abstract

The invention discloses a telescope frame control system. The signal input end of the motion controller is connected with the azimuth axis encoder and the pitch axis encoder, and the signal output end of the motion controller is connected with the azimuth axis driver, the pitch axis driver, and the azimuth axis driver. The pitch axis driver is connected to the torque motor of the azimuth axis and the torque motor of the pitch axis respectively; Position switch, position sensor, the signal output terminal of the microcontroller is connected to the power supply of the azimuth axis driver, the power supply of the pitch axis driver, the azimuth axis power-off brake, the pitch axis power-off brake, the stepper motor driver, the stepper motor driver is connected to the stepper motor, computer control Connect the motion controller and microcontroller. The invention effectively prevents failures caused by the azimuth axis and the pitch axis exceeding the motion range, and ensures safe operation of the telescope.

Description

A Telescope Rack Control System

technical field

The invention relates to the fields of control and electronics, in particular to a telescope frame control system.

Background technique

It is difficult for existing telescope systems to quickly track random moving targets, and a telescope system with faster speed, higher acceleration, and higher precision is required, and at the same time, it has perfect protection measures and a high degree of automation.

Contents of the invention

The invention provides a telescope frame control system, which solves the requirements for the speed, acceleration and precision of the telescope system. At the same time, multiple protections are designed to prevent system failure, and functions such as closed-loop focusing are designed. Specifically, it has the following functions: azimuth axis servo Control, pitch axis servo control, limit protection, stall protection, closed-loop focus control, etc.

The technical scheme adopted in the present invention is:

A telescope frame control system is characterized in that: it includes a computer, a servo control system and a single-chip control system, the servo control system includes a motion controller, and the signal input end of the motion controller is connected to an azimuth axis encoder and a pitch axis encoder , the signal output terminal of the motion controller is connected to the azimuth axis driver and the pitch axis driver, and the azimuth axis driver and the pitch axis driver are respectively controlled to connect to the azimuth axis torque motor and the pitch axis torque motor; The pitch axis speed measuring motor, the azimuth axis speed measuring motor, the pitch axis limit switch, the azimuth axis limit switch, and the position sensor are connected. A shaft power-off brake, a stepper motor driver, the stepper motor driver is connected to the stepper motor, the computer control is connected to a motion controller and a single-chip microcomputer, and the computer is also connected to an upper computer.

The above-mentioned telescope frame control system is characterized in that: the upper computer is an industrial control computer.

The control system of the telescope rack includes two parts: the servo control system and the single-chip microcomputer control system. The function is as follows:

1. Servo control system: the computer controls the motion controller, the motion controller is divided into two circuits, one path controls the azimuth axis driver, the azimuth axis driver controls the azimuth axis motor, and the motion controller obtains the position and speed of the azimuth axis through the azimuth axis encoder Information; the other way controls the pitch axis driver, the pitch axis driver controls the pitch axis motor, and the motion controller obtains the position and speed information of the pitch axis through the pitch axis encoder.

2. Single-chip microcomputer control system: The computer communicates with the single-chip microcomputer through the serial communication port, and the single-chip microcomputer control system completes the following functions.

(1) Control the drive power of the azimuth axis and the pitch axis.

(2) Control the power-off brakes of the azimuth and pitch axes.

(3) To adjust the focal length of the telescope, by controlling the stepping motor driver, and then controlling the stepping motor to adjust the focus, at the same time obtain the current focal length position through the position sensor, forming a closed-loop focusing device.

(4) Read the voltage value of the tachometer motor of the azimuth axis and the pitch axis to obtain the running speed of the azimuth axis and the pitch axis.

(5) Read the limit switch status of the azimuth axis and pitch axis.

The advantages of the present invention are:

The present invention adopts an industrial control computer as the upper computer, which has better expansibility and strong anti-interference ability; uses a single-chip microcomputer as the power control, system protection and focus control of the system, and has the characteristics of flexible control, small size and strong anti-interference ability ;The azimuth and pitch axes of the system are directly driven by a DC torque motor, which has good rigidity, high precision and low noise; the reflective encoder is used as the speed and position detection element, which is stable and reliable, with sufficient precision and resolution; rack control system The azimuth axis and the pitch axis are equipped with two speed limit protection functions and two position limit protection functions to prevent the azimuth axis and the pitch axis from exceeding the range of motion and cause failure, ensuring the safe operation of the telescope.

Description of drawings

Figure 1 is a block diagram of the rack control system.

Figure 2 is a block diagram of the servo control system.

Detailed ways

The principle block diagram of the frame control system is shown in Figure 1. A telescope frame control system includes a computer 2, a servo control system and a single-chip control system. The servo control system includes a motion controller 3, and the signal input of the motion controller 3 The terminal is connected to the azimuth axis encoder 4 and the pitch axis encoder 5. The signal output terminal of the motion controller 3 is connected to the azimuth axis driver 6 and the pitch axis driver 7. The azimuth axis driver 6 and the pitch axis driver 7 are respectively controlled to connect to the azimuth axis torque motor. 8. Pitch axis torque motor 9; the single-chip microcomputer control system includes a single-chip microcomputer 10, and the signal input end of the single-chip microcomputer 10 is connected with a pitch axis speed measuring motor 11, an azimuth axis speed measuring motor 12, a pitch axis limit switch 13, an azimuth axis limit switch 14, The position sensor 15, the signal output end of the single-chip microcomputer 10 are connected to the azimuth axis driver power supply 16, the pitch axis driver power supply 17, the azimuth axis power-off brake 18, the pitch axis power-off brake 19, the stepper motor driver 20, and the stepper motor driver 20 is connected to the stepper motor driver. Into the motor 21, the computer 2 is connected to a motion controller and a single-chip microcomputer, and the computer 2 is also connected to the upper computer 1.

The upper computer 1 adopts an industrial control computer.

Principle of the present invention and embodiment implementation process:

1. Azimuth axis, pitch axis servo control system

1. Fundamental

The structure of the servo control system of the azimuth axis and the pitch axis is the same. The servo control system is composed of a computer, a motion controller, a driver, a torque motor, and an encoder, forming a complete closed-loop system including a current loop, a speed loop, and a position loop, such as Figure 2 shows.

According to the control commands and motion requirements (position commands) of the host computer, the computer issues speed control commands to the motion trajectories of the azimuth axis and the pitch axis through appropriate algorithms (position PID adjustment). The update frequency of the speed control command is in the range of tens of Hertz to hundreds of Hertz.

According to the speed control command of the computer and the speed feedback of the encoder, the motion controller outputs the control voltage to the driver through PID adjustment.

The driver converts the control voltage into a PWM signal, which is amplified to drive the motor. Current feedback inside the drive is used to adjust the effect of load torque changes on speed.

the

2. Selection of main components

(1) The computer adopts industrial computer, Windows XP operating system, with multiple PCI expansion slots, USB interface, RS232/RS422/RS485 interface, LAN network interface, etc., which can fully meet the requirements of control and communication.

(2) The motion controller adopts the 7342 two-axis motion control card of NI Company in the United States, with 16-bit DAC (±10V) or 10-bit PWM (23.2KHz) output, differential or single-ended encoder input (20MHz bandwidth), each The axis minimum sampling time is 62.5μs.

(3) The encoder is a steel ring reflective grating encoder from British RENISHAW company, equipped with a 200 subdivision reading head. The outer diameter of the azimuth shaft encoder is 115 mm, the resolution is 0.36 arc seconds, and the accuracy is 1.94 arc seconds. The outer diameter of the pitch axis encoder is 103 mm, the resolution is 0.4 arc seconds, and the accuracy is 2.16 arc seconds. It can meet the resolution and precision required by the servo system.

(4) The motor is a DC torque motor from Chengdu Microfine Motor Co., Ltd. (Chengdu 906 Factory). The azimuth axis motor is J340LYX05G, the peak voltage is 60V, the torque is 180N.m, and the no-load speed is 60rpm. The pitch axis motor is J160LYX125G, the peak voltage is 60V, the torque is 50N.m, and the no-load speed is 80rpm.

the

2. SCM control system

1. The single-chip microcomputer control system completes the following functions.

(1) Control the drive power supply of the azimuth axis and the pitch axis. When the system is running normally, it supplies power to the servo system of the azimuth axis and the pitch axis. It is powered off when the system is shut down or in an emergency.

(2) Control the power-off brakes of the azimuth axis and the pitch axis. When the system is running normally, the power-off brakes of the azimuth axis and the pitch axis do not brake, and brake when the system is shut down or in an emergency.

(3) Realize the closed-loop adjustment of the focal length of the telescope, and adjust the focus by controlling the forward and reverse rotation of the stepping motor. The rotation of the motor will change the position of the position sensor, and the position of the focal length is obtained by reading the position of the sensor, forming a Closed-loop focusing device.

(4) Rotational speed measurement of the azimuth axis and the pitch axis. By reading the voltage value of the speed measuring motor of the azimuth axis and the pitch axis, the running speed of the azimuth axis and the pitch axis is obtained. This speed is mainly used for the speed limit function of the system to prevent the system from getting out of control .

(5) Read the state of the limit switch of the azimuth axis and the pitch axis. The limit switch is mainly used to prevent the rotation angle of the azimuth axis and the pitch axis from exceeding the limit.

2. Selection of main components

Microchip's dsPIC33FJ32MC304 is selected as the microcontroller, which is a high-performance microcontroller with DSP function, with a maximum working speed of 40MIPS, a 12-bit high-precision A/D converter, and rich peripheral interface circuits. the

3. Speed limit protection function

The azimuth and pitch axes have two independent speed limiting functions.

1. The running speed of the azimuth axis and the pitch axis is given by the motion controller, and the motion controller can obtain the running speed of the azimuth axis and the pitch axis in real time through the encoder on the azimuth axis and the pitch axis, so the motion controller is limited by software The speed output range of the system can ensure that the maximum operating speed of the system is within the set range when the system is running normally. When the speed limit of the motion controller is out of control, the single-chip microcomputer control system will provide stall protection.

2. The single-chip microcomputer can obtain the running speed of the azimuth axis and the pitch axis in real time through the speed measuring motor on the azimuth axis and the pitch axis. When the single-chip microcomputer detects that the speed exceeds the set maximum allowable operating range, the motor driver and the power-off brake will be disconnected at the same time. Supply power to brake the azimuth and pitch axes.

4. Limit protection function

The azimuth axis and the pitch axis are respectively provided with two independent limit functions.

1. The limit function of the azimuth axis: the motion controller obtains the running position of the azimuth axis in real time through the encoder on the azimuth axis. When the azimuth axis runs close to -360° or +360°, the motion controller will automatically reduce the running speed , when it reaches -361° or +361°, the motion controller will automatically limit the limit; if the limit of the motion controller fails, when it reaches -365° or +365°, the hardware limit switch will be turned on, and the microcontroller will detect After the hardware limit switch is turned on, cut off the power supply of the azimuth axis motor driver and the azimuth axis power-off brake at the same time to brake the azimuth axis.

2. The limit function of the pitch axis: the motion controller obtains the running position of the pitch axis in real time through the encoder on the pitch axis. When the pitch axis runs close to 0° or +90°, the motion controller will automatically reduce the running speed. When it reaches -1° or +91°, the motion controller will automatically limit the limit; if the limit of the motion controller fails, when it reaches -5° or +95°, the hardware limit switch will be connected, and the microcontroller will detect the hardware After the limit switch is turned on, cut off the power supply of the pitch axis motor driver and the pitch axis power failure brake at the same time, so as to brake the pitch axis.

5. Closed-loop focusing function

The execution of focusing is completed by the single-chip microcomputer controlling the stepping motor, and the computer sends the focusing information to the single-chip microcomputer through the serial port. The single-chip microcomputer generates control signals to the stepper motor according to these information, and at the same time feeds back the sampled position information of the position sensor to the computer through the serial port, and displays the current focal length position on the computer. There are two modes for focusing:

1. In speed and direction mode, the MCU receives the speed and direction commands from the computer through the serial port, and the stepping motor runs in accordance with the speed and direction given by the computer.

2. In positioning mode, the single-chip microcomputer accepts the positioning position given by the computer through the serial port, and the single-chip microcomputer controls the stepper motor to stop focusing after reaching the positioning position.

Claims (2)

1. a telescope mill stand control system, it is characterized in that: include computing machine, servo-control system and single-chip computer control system, servo-control system includes motion controller, the signal input part connection orientation shaft encoder of motion controller, pitch axis scrambler, the signal output part control linkage azimuth axis driver of motion controller, pitch axis driver, azimuth axis driver, pitch axis driver control linkage azimuth axis torque motor, pitch axis torque motor respectively; Single-chip computer control system includes single-chip microcomputer, the signal input part of single-chip microcomputer is connected with pitch axis speed measuring motor, azimuth axis speed measuring motor, pitch axis limit switch, azimuth axis limit switch, position transducer, the signal output part connection orientation axle drive power supply of single-chip microcomputer, pitch axis drive power supply, azimuth axis electricity loss brake, pitch axis electricity loss brake, stepper motor driver, stepper motor driver connects stepper motor, computer control connects motion controller, single-chip microcomputer, and computing machine also connects host computer.

2. a kind of telescope mill stand control system according to claim 1, is characterized in that: described host computer adopts industrial control computer.

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