CN202433721U - Servo controller for tri-axial antenna test robot - Google Patents

Abstract

The utility model designs a three-axis antenna testing robot servo controller, which belongs to the field of electromechanical control. It is characterized in that it includes a three-axis motion control board, and the periphery of the control board has a touch screen man-machine interface, a host computer interface, a three-axis feedback channel, a three-axis limit module and a three-axis drive module. The touch screen human-machine interface realizes the human-computer interaction function of the controller; the host computer interface connects the controller and the user's host computer to realize the remote control of the antenna test robot; the three-axis feedback channel collects the real-time angle data of each axis of the antenna test robot; three The axis limit module is used for the electrical limit of each axis of the antenna test robot; the three-axis drive module drives the movement of each motor of the antenna test robot. The utility model provides an effective and low-cost solution for a three-axis control system based on a permanent magnet DC torque motor, which can control the time-sharing independent movement of the three axes, and can also control the simultaneous associated movement of the three axes.

Description

Three-axis antenna test robot servo controller

technical field

The utility model designs a three-axis antenna testing robot servo controller, which belongs to the field of electromechanical control. the

Background technique

The three-axis antenna test robot is a kind of equipment used to test the performance of the antenna. The three-axis antenna test robot has three motion axes: azimuth motion axis, pitch motion axis and compensation motion axis, in which the azimuth motion axis adjusts the azimuth angle of the antenna under test, and the motion range is 0° to 360°. Independent. The pitch motion axis adjusts the pitch angle of the antenna under test, and the compensation motion axis compensates for the motion deviation of the pitch axis to ensure that the phase center of the antenna under test remains unchanged. Therefore, the pitch motion axis and the compensation motion axis must coordinate synchronous movements, and the pitch angle and compensation angle The range of motion is 0°～90°. the

In the field of electromechanical control, there are many components to build a servo control system. As far as the selection of actuators is concerned, some use AC servo motors, some use stepper motors, some use brushless DC motors, and some use brushed DC motors. Motors, etc. Different motors need to be matched with different drivers; as far as the selection of feedback measurement components is concerned, some use photoelectric encoders, some use grating rulers, some use resolvers, and some use Hall sensors, etc., according to different According to the control needs, choose different sensors. the

The three-axis antenna test robot is a typical three-axis servo system. This type of robot uses a permanent magnet DC torque motor as the actuator of each motion axis. It requires the position control accuracy of each motion axis to be greater than 0.1°. It adopts 14-bit absolute photoelectric coding. The sensor is used as the position measuring element of each movement axis, the infrared photoelectric switch is used as the limit detection element of each movement axis, and the touch screen is used as the human-computer interaction interface. the

Contents of the invention

The purpose of the utility model is to provide an effective and low-cost control scheme for a three-axis antenna testing robot, which can also be applied to other three-axis servo control systems based on permanent magnet DC torque motors. the

The utility model discloses a three-axis antenna testing robot controller, which is characterized in that it comprises a three-axis motion control board, a touch screen human-machine interface, a host computer interface, a three-axis feedback channel, a three-axis limit module and Three-axis drive module. the

The three-axis motion control board uses PIC24HJ128GP506 single-chip microcomputer as the control core, expands a piece of EEPROM for storing working parameters, expands three RS485 interfaces for connecting feedback channels, and expands one CAN field bus interface for remote networking control. the

The man-machine interface of the touch screen is RS232 interface, connected to a 7-inch 64K true color serial touch screen. the

The upper computer interface is RS232 interface, which can be directly connected to a computer with RS232 interface to implement remote automatic control of the antenna test robot. the

All three-axis feedback channels are RS485 interfaces, which can be connected to various angular position sensors with RS485 interfaces. The accuracy of the sensor can be determined according to actual needs. When a 14-bit absolute photoelectric encoder is used, it can ensure that the angular position measurement accuracy of each axis is greater than 0.03°, and the angular velocity measurement accuracy is greater than 0.1°/S. the

The three-axis limit modules all adopt photoelectric isolation input, the maximum input current is 100mA, and can be connected to various switch detection sensors that support open collector output, such as: photoelectric switch, proximity switch After the braking signal is activated, the motor can be braked urgently. the

The three-axis drive module adopts PWM wave H-bridge power amplifier, which can drive permanent magnet DC torque motor. The drive module has an emergency brake signal interface and a high-speed PWM wave drive signal photoelectric isolation interface. The maximum operating frequency of the drive module is 20KHz, and the maximum drive voltage It is 28V and the maximum operating current is 48A. the

The advantages of the device disclosed in the utility model are described as follows:

(1) Economy. Because the utility model adopts the self-made PWM wave H-bridge power amplifier module, not only can well complete the various performance indicators of the three-axis antenna test robot, but also save the overall cost of the controller by 20% compared with the traditional linear power amplifier module about. the

(2) Accuracy. The actual control accuracy of the utility model depends on the effective accuracy of the sensor. Since the controller uses the RS485 bus to directly communicate with the absolute photoelectric encoder, there is almost no accuracy loss in the collection of the feedback signal, which makes the position control accuracy of the controller possible. On the same order of magnitude as the effective accuracy of the sensor. the

(3) Simplicity. Since the utility model adopts a 7-inch 6K true-color touch display screen as the human-computer interaction interface, it is more humanized than the traditional method of LED display and button input, and makes the user's manual operation more simple and convenient. In addition, the controller also has a host computer interface for connecting to a computer for remote automatic control. Users can choose any method to control the three-axis antenna test robot according to their needs. the

(4) Reliability. The utility model adopts a variety of measures to improve the reliability of the control system, such as adopting RS485 bus to transmit feedback signals to enhance the anti-interference ability of the system; the control board can supply power with wide voltage, and has the ability to prevent overvoltage, undervoltage, reverse connection of power supply and short circuit and other functions; the controller adopts multiple protection functions, software protection can prevent users from illegal data input and abnormal feedback data; both the control board and the motor drive module have electrical limit protection, and the double electrical limit further enhances the reliability of the control system. the

Description of drawings

Figure 1 is the overall structure diagram of the three-axis antenna test robot servo control system

The part inside the dotted box is the servo controller of the three-axis antenna test robot. the

Figure 2 is the structural diagram of the three-axis antenna test robot servo controller control board

The control board takes PIC24HJ128GP506 microcontroller as the control core, has a dedicated reset circuit and power supply module, expands a piece of EEPROM for storing working parameters, expands three RS485 interfaces for connecting feedback channels, and expands one CAN field bus interface for remote networking control , providing one touch screen interface, one host computer interface, three-axis limit module and three-way drive module, etc. the

Figure 3 is the circuit schematic diagram of the three-axis antenna test robot servo controller drive module

The three-axis antenna test robot servo controller drive module is used to drive the DC torque motor (B1), which consists of two half-bridge drive chips BTN7970 (U2 and U3) to form an H-shaped full-bridge drive circuit. The external input signals mainly include two complementary PWM wave signals (PWMH and PWML) and one emergency braking signal (Break). The two-way PWM signal is input after being isolated by the high-speed optocoupler (U4), and the brake signal is input after being isolated by the low-speed optocoupler (U1). the

Figure 4 is the rendering of the main interface of the human-computer interaction of the three-axis antenna test robot servo controller

The main human-computer interaction interface is divided into three parts. The part in the dotted box 1 is the display area of the three-axis angle given value and feedback value. The part in the dotted box 2 is the display area of the system status and operation status. Part of it is the touch button area. the

Detailed ways

The utility model aims to provide an effective and low-cost control scheme for a three-axis antenna testing robot. It should be understood that the utility model can also be applied to other similar three-axis servo control systems. the

Figure 1 shows the overall structure of the three-axis antenna test robot servo control system. The part inside the dotted line box is the three-axis antenna test robot servo controller, including a three-axis motion control board, with touch screen man-machine interface and host computer interface on the periphery , three-axis feedback channel, three-axis limit module and three-axis drive module, etc., as detailed below: 

The three-axis motion control board uses PIC24HJ128GP506 single-chip microcomputer as the control core. This type of single-chip microcomputer is produced by Microchip. It is a 16-bit high-end single-chip microcomputer with a main frequency of up to 40M and an 8K RAM space on the chip. It can run a small embedded operating system. The utility model develops all control software based on μC/OS-II embedded operating system. the

Since there are many types of power supplies on the control board, including 5V, 3.3V, 28V and other multiple power sources, the power supply system is specially designed on the control board, using a 28V switching power supply as the main power supply of the controller, which is stabilized by the LM2576-5V chip as a 5V power supply. The power supply is used as a 3.3V power supply after being regulated by the ASM1117-3.3V chip. In addition, the MAX811-2.4V chip is also used to build a dedicated reset circuit module for the control board. the

Since the PIC24HJ128GP506 MCU itself does not have an EEPROM, the I2C bus of the MCU is used to expand a piece of EEPROM to store working parameters. The chip model is 24LC64, which can store up to 8K bytes of data. the

In order to realize the scalability of the control function of the three-axis antenna test robot, for example, some new functional modules may be added to the control system in the future, or the three-axis antenna test robot may be incorporated into a larger network system for control, so for the control The device expands one CAN field bus interface, and the CAN transceiver model is PCA82C250. the

The human-machine interface of the touch screen adopts a 7-inch 64K true-color serial touch screen, the model is DMT80480C070_01W. The communication mode of this type of touch screen is RS232 bus interface, which has the characteristics of convenient development and flexible use. It can be easily designed by using the auxiliary development software provided by the touch screen manufacturer. Create a beautiful man-machine interface. Figure 4 is the effect diagram of the main interface of the human-computer interaction of the servo controller of the three-axis antenna test robot. the

In order to reduce the operating burden of the staff, the servo controller of the three-axis antenna test robot is extended with a host computer serial communication interface, which can be directly connected to a computer with an RS232 interface to implement remote automatic control of the antenna test robot. The communication protocol has been written inside the controller, and the user can develop the upper computer control software by himself according to the needs. the

In order to simplify the system design and enhance the anti-interference ability of the system, the utility model uses the RS485 bus to construct the feedback data transmission channel. The PIC24HJ128GP506 single-chip microcomputer only has two serial ports, and the control system needs three feedback channels in total, so the parallel-serial conversion chip SC16C554 is used Extend the three-way RS485 bus interface, the control board can be directly connected to all position sensors or transmitters with RS485 interface. The three-axis antenna test robot uses a 14-bit absolute photoelectric encoder E1042Ad6-14. The angular position measurement error of this type of encoder is less than 0.03°, and the angular velocity measurement error is less than 0.1°/S. the

The three-axis limit modules of the controller all adopt photoelectric isolation input, the maximum input current is 100mA, and can be connected to various switching value detection sensors that support open collector output, such as: photoelectric switch, proximity switch or travel switch, etc., when the control board After the limit brake signal is detected, the motor can be braked urgently. the

The utility model has independently developed a motor drive module to save development costs, and Fig. 3 is a circuit schematic diagram of the drive module. The module uses two half-bridge driver chips BTN7970 to form an H-type full-bridge driver circuit. Two PWM wave signals with complementary waveforms are input after being isolated by high-speed optocouplers, and one emergency brake signal is input after being isolated by low-speed optocouplers. This module can drive a permanent magnet DC torque motor with a maximum operating frequency of 20KHz, a maximum driving voltage of 28V, and a maximum operating current of 48A. the

Specific working principle

The three-axis antenna test robot servo controller is a typical position closed-loop feedback control system. The given value of the three-axis position is input by the touch screen human-machine interface, and the feedback loop is formed by an absolute photoelectric encoder with RS485 interface. The single-chip microcomputer collects the given position value. and the feedback value, call the programmed PID control algorithm to implement closed-loop control on the three-axis position, in which the pitching axis and the compensation axis are synchronously controlled. The three-axis position control error is less than 0.1°. the

Claims (5)

1. A three-axis antenna testing robot servo controller is characterized in that: it comprises a three-axis motion control board, and the periphery of the control board has a touch screen man-machine interface, a host computer interface, a three-axis feedback channel, a three-axis limit module and three Shaft drive module. 2. The three-axis antenna test robot servo controller according to claim 1 is characterized in that: the three-axis motion control board takes PIC24HJ128GP506 single-chip microcomputer as the control core, expands a slice of EEPROM for storing operating parameters, and expands three-way RS485 interface It is used to connect the feedback channel and expand a CAN field bus interface for remote networking control. 3. The three-axis antenna testing robot servo controller according to claim 1, characterized in that: the man-machine interface of the touch screen is an RS232 interface, which is connected with a 7-inch 64K true-color serial touch screen. 4. The three-axis antenna testing robot servo controller according to claim 1, characterized in that: all of the three-axis feedback channels are RS485 interfaces, which can be connected to various angular position sensors with RS485 interfaces. 5. The three-axis antenna testing robot servo controller according to claim 1, characterized in that: the three-axis driving module adopts a PWM wave H-bridge power amplifier, which can drive a permanent magnet DC torque motor, and the driving module comes with an emergency Brake signal interface and high-speed PWM wave drive signal photoelectric isolation interface, the maximum operating frequency of the drive module is 20KHz, the maximum driving voltage is 28V, and the maximum operating current is 48A. the

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