CN106502162A - A kind of automatic Control Theory Experiment teaching system based on portable mechanical arm - Google Patents

Abstract

The invention discloses an automatic control theory experiment teaching system based on a portable mechanical arm, relates to an automatic control theory experiment teaching device, and belongs to the teaching field. Including the controlled object, controller, actuator and feedback device, it constitutes a complete closed-loop control system loop. The controlled object is a nested combination of a mechanical arm and a DC motor, which is used to generate an angular position signal. The controller is used to make the output of the controlled object converge to a predetermined value quickly and stably. The controller adjusts the static and dynamic characteristics of the system according to the control algorithm of the control system, which is the research content of the automatic control theory experiment teaching system. The actuator is a DC motor, which controls the rotation of the mechanical arm and realizes the position control of the mechanical arm. The feedback device adopts unit negative feedback, which is used to detect the actual angular position signal of the mechanical arm and return the signal to the controller. The invention has the following advantages: portability; low cost and energy consumption; relatively complete functions; strong anti-interference ability. The invention is suitable for the experimental teaching of the automatic control theory course.

Description

A teaching system for automatic control theory experiment based on portable manipulator

technical field

The invention relates to an automatic control theory experiment teaching device, in particular to an automatic control theory experiment teaching device based on a portable mechanical arm, which is suitable for undergraduate students' automatic control theory experiment teaching and belongs to the teaching field.

Background technique

In the setting of professional courses for undergraduate training in colleges and universities, in addition to theoretical teaching, there is also experimental teaching. Experimental teaching can stimulate researchers' interest in continuing to explore scientific mysteries. There is a big disadvantage in today's college education, that is, a large number of students are engaged in theoretical research, only through software simulation, and seldom carry out physical experiments to verify their theoretical methods.

At this stage, most of the automatic control theory experiments in universities use MATLAB simulation to verify the effect of classical algorithms, which makes students learn more abstractly. A small number of undergraduate colleges use the inverted pendulum system or the compound network method to conduct experiments.

The inverted pendulum system is a commonly used device for the teaching device of the automatic control theory experiment. The control problem of the inverted pendulum is to make the pendulum reach a balance position as soon as possible without large oscillation and excessive angle and speed. When the pendulum reaches the desired position, the system can use the corresponding algorithm to overcome random disturbances to maintain a stable position.

The input of the inverted pendulum system comes from the actual position signal of the trolley and the pendulum rod of the sensor. After comparing with the expected value, the control value is obtained through the control algorithm, and then the DC motor is driven by digital-to-analog conversion to realize the real-time control of the inverted pendulum. The specific process is as follows: one end of the pendulum rod is installed on the trolley, and the force acts on the trolley parallel to the running direction of the trolley, so that the rod rotates around the axis on the trolley in the vertical plane, and the trolley moves along the horizontal rail. When there is no force , the swing rod is in a vertical stable equilibrium position (vertically downward), in order to make the rod swing or reach vertically upward stability, it is necessary to give the dolly a control force so that it is pulled forward or backward on the track.

By analyzing the force of the trolley, the transfer function between the angle of the pendulum and the acceleration of the trolley can be obtained as:

It can be seen from the transfer function that the system is a second-order system, and the function and accuracy of the classical algorithm can be verified through the analysis and control of the second-order system.

Disadvantages of the inverted pendulum system: ①The system model is established under various ideal conditions, such as ignoring air resistance and various frictions. The pendulum must be a homogeneous rod. It is predictable, and there is no homogeneous rod in reality, so the accuracy of the experiment is reduced, and the realization of the subsequent control algorithm is more difficult; ②The system includes the guide rail for the trolley, the motor for driving the trolley, and the swing rod and other devices , so it is bulky and difficult to move and carry around. Among them, in order to keep the pendulum stable, the trolley needs to run continuously, and the length of the guide rail needs to be at least 1 meter. This system is just an ideal model. The mathematical model of the inverted pendulum system is established by the Newton-Euler method, and the model is analyzed through the open-loop response analysis. The controller of the system is designed by using classical control theory and Matlab/Simulink simulation software.

Composite network method to simulate various typical links: use different input networks and feedback networks of operational amplifiers to simulate various typical links, and then connect these simulated links according to the structure diagram of a given system to obtain the corresponding analog system. Then add the input signal to the input end of the analog system, and use a computer and other measuring instruments to measure the output of the system, and then the dynamic response curve and performance index of the system can be obtained. If the parameters of the system are changed, the influence of the parameters on the performance of the system can be further analyzed and studied.

For example: Figure 1 is the lead correction circuit diagram of the second-order system, the system adds a step signal, measures the system step response, and records the overshoot σ% and the adjustment time t _s ; the switch s is turned on, repeat the above steps, and the two By comparing the measured waveform with the numerical value, the effect of advanced correction can be obtained.

Disadvantages of composite network simulation: ①Composite network simulation of various typical links needs to temporarily build different working platforms according to different algorithms. For example, if you need to verify the lead correction, you need to build the module as shown above. Need to rebuild. ②It is an open-loop system without a feedback link. When the system is unstable, the system can only be approached to be stable by adjusting the size of each electronic component.

Contents of the invention

The technical problem to be solved by the automatic control theory experiment teaching system based on a portable mechanical arm disclosed by the present invention is to provide a small and portable robot automatic control theory experiment teaching system, which can complete the main experiments in the automatic control theory teaching. .

The invention also discloses a typical teaching method realized by a portable mechanical arm-based automatic control theory experiment teaching system.

The purpose of the present invention is achieved through the following technical solutions:

The invention discloses an automatic control theory experiment teaching system based on a portable mechanical arm, which includes a controlled object, a controller, an actuator and a feedback device, forming a complete closed-loop control system loop.

The controlled object is a nested combination of a mechanical arm and a DC motor, which is used to generate an angular position signal. As shown in Figure 2, the angular position of the manipulator is the controlled object S, where S(r) is the reference position, ie the target position, and S(t) is the current position of the manipulator, ie the actual position.

The controller is used to make the output of the controlled object converge to a predetermined value quickly and stably. The controller adjusts the static and dynamic characteristics of the system according to the control algorithm of the control system, which is the research content of the automatic control theory experiment teaching system. The control algorithm of the control system adjusts the static and dynamic characteristics of the system by software programming.

The actuator is a DC motor, and the DC motor controls the rotation of the mechanical arm to realize the position control of the mechanical arm. The characteristics of a DC motor are considered fixed after leaving the factory, and the mathematical model of a DC motor is determined by its own electrical characteristics.

The feedback device adopts unit negative feedback, which is used to detect the actual angular position signal of the mechanical arm and return the signal to the controller. The feedback device is preferably realized by a photoelectric encoder.

The position of the DC motor is taken as the research object of the automatic control theory experiment teaching system. In order to observe the experimental results more intuitively, a mechanical arm is connected to the output shaft of the DC motor as an indicator of the position of the motor. Use the controller for position control of the robotic arm.

The controller includes a PC upper computer and an ARM lower computer; first, the voltage signal of the PC upper computer is transmitted to the MCU main control module through the USB serial port transmission module, and the internal timing/timer of the ARM control chip generates a square wave with a controllable duty ratio Drive the DC motor and drive the mechanical arm to rotate; the angular position signal of the DC motor is transmitted to the MCU main control module through the two feedback signals of the feedback device, and the rotation direction and angular position of the mechanical arm are judged through the internal counter and phase logic analysis of the ARM control chip. Finally, the angular position signal is transmitted to the PC host computer for the calculation of the voltage signal value in the next step and displayed on the front-end display module. At the end of the experiment, the rotation of the DC motor drives the rotation of the mechanical arm to achieve the final stability of the mechanical arm.

The MCU main control module adopts a low-cost ARM control chip, which is responsible for the initialization and control of all other peripheral circuits, driving the DC motor to rotate and receiving the signal of the position feedback device of the photoelectric encoder, and sending the obtained results to the PC through the USB serial port module. The computer platform; the USB serial port transmission module can provide power for the ARM lower computer, and it is the data transmission interface between the ARM lower computer and the PC upper computer; the motor drive module, the driving circuit of the linear amplification of the mechanical arm adopts a dual-channel PWM driving voltage , the driving signal is obtained by the timer/counter that comes with the ARM control chip to drive the motor to rotate forward, reverse and stop. At the same time, a logic protection circuit is designed to protect the driving circuit; the feedback device is used to detect the actual angle of the mechanical arm The position signal is fed back to the MCU main control module, and the feedback device is the feedback part of the whole automatic control theory experiment teaching system.

The mathematical model of the DC motor is as follows: according to the electrical characteristics of the DC motor, the position model of the DC motor is divided into two parts: the speed model and the position integration link, and the speed model is first obtained through the identification algorithm, and then combined with the position integration link to obtain a complete location model. As shown in FIG. 3 , the open-loop mathematical model of the position system of the DC motor can be obtained through the modeling method described above. In order to calculate the two parameters of T _m and K _e , the speed control of DC motor is taken as the research object, because the model corresponding to the speed control of DC motor is a standard first-order model Where T _m is the standard time constant of the position system, assuming that the speed of the system when the speed is stable in a step response is t, the corresponding time when the system speed reaches 0.632t is T _m . Where U _f represents the voltage equivalent to the input terminal of the unknown time-varying nonlinear frictional disturbance torque that produces a dead zone in the position system, y represents the position of the motor, v represents the speed, let T _m be the time constant of the DC motor, and K _e be the motor The speed feedback proportional coefficient of , where T _m and K _e are the electrical characteristic constants of the position system, and U _f is the equivalent voltage of the nonlinear dead zone of the system. When the hardware system is established, the software compensation of the DC drive is performed on the dead zone , so that the position model of the DC motor is obtained as It can be seen that the position system is a standard second-order system, and the parameter K _e is calculated according to the step response curve of the motor position control. After many experiments and calculations, the two parameters of system T _m and K _e are finally obtained to be 0.15 and 0.56 respectively. Therefore, the DC motor position model is

The appearance of the automatic control theory experiment teaching system based on a portable mechanical arm disclosed by the present invention is preferably box-packed, and the controller, actuator and feedback device are all packaged, and the design idea of modularization is adopted, only the interface and the external Interaction, design a dial on the top of the box, the DC motor is fixed inside the box, the output shaft of the DC motor protrudes from the top of the box, and is connected with a pointer, which is helpful to observe the experimental phenomenon of automatic control theory, better analysis of experimental results.

The connection relationship of the hardware space position: the boxed experiment box is used to package the equipment, the connecting wires needed for the experiment can be stored in the storage room, the dial is used to display the rotation angle of the mechanical arm, the pointer is used to display the mechanical rotation, and the DC power plug The hole is an optional DC 12V power supply socket for the DC motor. The USB data interface/DC power supply connection port is the interface for connecting the experimental equipment to the PC host computer, and supplies power to the ARM lower computer. The motor power supply switch is the motor power supply voltage level (5V /12V) switching button, the power switch is the main switch of the test box.

Because the automatic control theory experiment teaching system based on the portable manipulator disclosed in the present invention is designed for the teaching of the automatic control theory course, the analysis method of the automatic control theory course mostly adopts the graphical method, such as system response, root locus, frequency characteristics The lamp needs to draw a large number of curves, so in addition to the experimental device, a host computer platform is also designed to assist teaching.

The experiment selection unit of the host computer platform assisted teaching is used to select the required experiment before the experiment; the parameter modification unit: before the experiment starts, the students must fill in the corresponding experimental parameters in the parameter modification box, if not filled, it will be used Default parameters; data calculation unit: analyze and calculate the real-time data returned by the ARM lower computer, calculate and analyze the received real-time information, and convert ordinary data into symbol information applied by automatic control theory, which is convenient for students to watch and Understanding; data display unit: students can not only observe the experimental phenomenon on site, but also quantitatively observe various real-time data of the experimental system through the host computer platform. In addition, this unit will also display the real-time curve of the controlled object in the host computer software ;Experimental control unit: control the progress of the experiment, the experiment can be started, stopped, and ended at any time, or after the experiment is over, the previous experimental data can be called to observe and compare; communication unit: responsible for real-time communication with the experimental device, sending control The command also receives the data information returned by the experimental device.

Auxiliary teaching function of host computer platform:

(1) Control the experimental device to conduct experiments: use the host computer to send control commands to the experimental device. The start, pause, and end of the experiment, the selection of the control algorithm, and the readback of the parameters are all controlled through the host computer platform, and the experimental device completes the experiment by receiving the control commands from the host computer.

(2) Display the experimental curve and analyze the experimental data: due to the characteristics of the course of automatic control theory, drawing is a must-achieve function of the host computer platform, and the host computer platform receives the experimental data returned by the experimental device, such as the angle and position of the mechanical arm, etc. , through calculation and sorting, and display it to students in the form of curves, data tables, etc., in order to achieve a good teaching effect.

The control strategy of the upper computer includes:

From the mathematical model of the DC motor of the portable manipulator, the closed-loop pole without adding a controller can be obtained. In order to optimize the static and dynamic characteristics of the system and improve the control effect, it is necessary to add a control algorithm to the system. The control algorithm includes:

PID controller design: the mathematical model of the control system, the control law is:

Therefore, in the PID control experiment, a total of 3 parameters were designed, namely Kp, Ti, Td. When conducting experiments, by modifying these three parameters and making comparisons, it can be obtained that the proportional-integral-differential link plays a role in the controller.

Lead-lag controller design: Similar to the PID control experiment, in the lead-lag control experiment, a total of 3 parameters were designed, namely K, Ti, and Td. During the experiment, students can modify the parameters of the controller through the host computer control platform, and obtain the function of the lead-lag controller by using different control parameters.

Custom algorithm design: In this module, students can verify whether the algorithm they write can achieve a good control effect. They can convert the program they write into a dynamic link library (.dll) format and upload it to the PC host computer, and run the program. By analyzing the relevant dynamic and static performance indicators in the obtained curves, the parameters to measure the control performance of the algorithm can be obtained, and the control algorithm can be verified by modification.

Root locus correction experiment: By designing the transfer function of the correction network, the performance index of the system can meet the given requirements, including series lead correction and series lag correction.

The frequency method correction experiment is similar to the root locus. By designing the transfer function of the correction network, the performance index of the system can meet the given requirements, including series lead correction and series lag correction.

In the pole allocation experiment, through the analysis of the original system, the stable poles and zero points of the system are obtained, and the pole allocation method is used to configure the system to make the system meet the given goal.

Linear quadratic final control algorithm control experiment, including LQR control algorithm, simulation of LQR controller, elimination of steady-state error and actual control of LQR controller.

The DC motor modeling experiment, through the acquisition and data analysis of the angle position of the DC motor when it starts, obtains the model parameters of the DC motor from specific experiments.

Beneficial effect:

1. The invention discloses an automatic control theory experiment teaching system based on a portable manipulator, using a DC motor as an experimental device, and using a low-power ARM single-chip microcomputer for actual control, which greatly reduces cost and energy consumption.

2. The teaching system for automatic control theory experiment teaching system based on portable mechanical arm disclosed by the present invention adopts a closed-loop control system with relatively complete functions and can complete all experiments in theoretical teaching, making students learn more concretely and understand theoretical knowledge more clearly. thorough.

3. The invention discloses an automatic control theoretical experiment teaching system based on a portable manipulator. The closed-loop operation of the manipulator is completely consistent with the theoretical knowledge and does not involve various simulations. It solves the problem that current mainstream experimental equipment needs to be simulated. .

4. A teaching system for automatic control theory experiment teaching system based on a portable mechanical arm disclosed in the present invention has strong anti-interference ability, and can directly experiment without readjusting parameters when the external environment changes;

5. A portable mechanical arm-based automatic control theory experiment teaching system disclosed in the present invention, by encapsulating the control platform and the actuator, it can be more conveniently carried to the classroom for teaching demonstration while ensuring the aesthetics , with strong portability.

6. In the teaching system for automatic control theory experiment teaching system based on a portable mechanical arm disclosed in the present invention, students can customize the control algorithm, upload it to the PC host computer by generating a dynamic link library, run the program, and obtain the curve Analyze relevant dynamic and static performance indicators in the experiment, and verify whether the algorithm written by oneself can achieve good control effect through this experimental device.

Description of drawings

Fig. 1 is the lead correction circuit diagram in the background technology;

Fig. 2 is a model diagram of the portable manipulator control system;

Fig. 3 is the mathematical model of DC motor;

Fig. 4 is a working block diagram of the portable manipulator control system;

Fig. 5 is the schematic diagram of portable experimental device;

Fig. 6 is the composition of mechanical arm equipment system;

Among them ① experiment box ② storage room ③ dial ④ pointer ⑤ 12V DC power jack ⑥ USB data interface/DC 5V power connection port ⑦ network port ⑧ motor power switch ⑨ power switch

Figure 7 is a structural diagram of the upper computer platform;

Figure 8 is the mathematical model of the PID control system.

detailed description:

The present invention will be described in detail below in conjunction with accompanying drawing and embodiment, also described the technical problem and beneficial effect that the technical solution of the present invention solves simultaneously, it should be pointed out that described embodiment is only intended to facilitate the understanding of the present invention, and It has no limiting effect on it.

Example 1:

As shown in Figures 2 and 4, this embodiment discloses an automatic control theory experiment teaching system based on a portable manipulator, including a controlled object, a controller, an actuator and a feedback device, forming a complete closed-loop control system loop.

The controlled object is a nested combination of a mechanical arm and a DC motor, which is used to generate an angular position signal. The angular position of the manipulator is the controlled object S, where S(r) is the reference position, ie the target position, and S(t) is the current position of the manipulator, ie the actual position.

The controller is used to calibrate the mathematical model of the system so that it can converge to a predetermined value. The controller adjusts the static and dynamic characteristics of the system according to the control algorithm of the control system, which is the research content of the automatic control theory experiment teaching system. The control algorithm of the control system adjusts the static and dynamic characteristics of the system by software programming.

The actuator is a DC motor, and the DC motor controls the rotation of the mechanical arm to realize the position control of the mechanical arm. The characteristics of a DC motor are considered fixed after leaving the factory, and the mathematical model of a DC motor is determined by its own electrical characteristics.

The feedback device adopts unit negative feedback, which is used to detect the actual angular position signal of the mechanical arm and return the signal to the controller. The feedback device is realized by a photoelectric encoder.

The position of the DC motor is taken as the research object of the automatic control theory experiment teaching system. In order to observe the experimental results more intuitively, a mechanical arm is connected to the output shaft of the DC motor as an indicator of the position of the motor. Use the controller for position control of the robotic arm.

As shown in Figure 4, the controller includes a PC upper computer and an ARM lower computer; first, the voltage signal of the PC upper computer is transmitted to the MCU main control module through the USB serial port transmission module, and is generated by the internal timer/timer of the ARM control chip The controllable duty ratio square wave drives the DC motor and drives the mechanical arm to rotate; the angular position signal of the DC motor is transmitted to the MCU main control module through the two-way feedback signal of the feedback device, and the internal counter and phase logic analysis of the ARM control chip are used to determine the position of the mechanical arm. The rotation direction and angular position, and finally the angular position signal is sent to the PC host computer for the calculation of the voltage signal value in the next step and displayed on the front-end display module. At the end of the experiment, the rotation of the DC motor drives the rotation of the mechanical arm to achieve the final stability of the mechanical arm.

As shown in Figure 2, the ARM lower computer includes an MCU main control module, a USB serial port transmission module, a motor drive module and a feedback device. The MCU main control module adopts a low-cost ARM control chip, which is responsible for the initialization and control of all other peripheral circuits, driving the DC motor to rotate and receiving the signal of the position feedback device of the photoelectric encoder, and sending the obtained results to the PC through the USB serial port module. The computer platform; the USB serial port transmission module can provide power for the ARM lower computer, and it is the data transmission interface between the ARM lower computer and the PC upper computer; the motor drive module, the driving circuit of the linear amplification of the mechanical arm adopts a dual-channel PWM driving voltage , the driving signal is obtained by the timer/counter that comes with the ARM control chip to drive the motor to rotate forward, reverse and stop. At the same time, a logic protection circuit is designed to protect the driving circuit; the feedback device is used to detect the actual angle of the mechanical arm The position signal is fed back to the MCU main control module, and the feedback device is the feedback part of the whole automatic control theory experiment teaching system.

As shown in Figure 3, the mathematical model of the DC motor is as follows: according to the electrical characteristics of the DC motor, the position model of the DC motor is divided into two parts: the speed model and the position integration link, and the speed model is first obtained through the identification algorithm, and then combined with A complete position model is obtained by combining the position integration links, and the open-loop mathematical model of the position system of the DC motor can be obtained through the modeling method. In order to calculate the two parameters of T _m and K _e , the speed control of DC motor is taken as the research object, because the model corresponding to the speed control of DC motor is a standard first-order model Where T _m is the standard time constant of the position system, assuming that the speed of the system when the speed is stable in a step response is t, the corresponding time when the system speed reaches 0.632t is T _m . Where U _f represents the voltage equivalent to the input terminal of the unknown time-varying nonlinear frictional disturbance torque that produces a dead zone in the position system, y represents the position of the motor, v represents the speed, let T _m be the time constant of the DC motor, and K _e be the motor The speed feedback proportional coefficient of , where T _m and K _e are the electrical characteristic constants of the position system, and U _f is the equivalent voltage of the nonlinear dead zone of the system. When the hardware system is established, the software compensation of the DC drive is performed on the dead zone , so that the position model of the DC motor is obtained as It can be seen that the position system is a standard second-order system. According to the step response curve of the motor position control, the parameter K _e is calculated. After many experiments and calculations, the two parameters of system T _m and K _e are finally obtained to be 0.15 and 0.56 respectively. Therefore, the DC motor position model is

As shown in Figures 5 and 6, a portable manipulator-based automatic control theory experimental teaching system disclosed in this embodiment is box-packed, and the controller, actuator and feedback device are all packaged, and a modularized Design idea, only leave the interface to interact with the outside, design a dial on the top of the box, the DC motor is fixed inside the box, the output shaft of the DC motor protrudes from the top of the box, and is connected to a pointer, which helps Observe the experimental phenomena of automatic control theory, and better analyze the experimental results.

The connection relationship of the hardware space position: the boxed experiment box is used to package the equipment, the connecting wires needed for the experiment can be stored in the storage room, the dial is used to display the rotation angle of the mechanical arm, the pointer is used to display the mechanical rotation, and the DC power plug The hole is an optional DC 12V power supply socket for the DC motor. The USB data interface/DC power supply connection port is the interface for connecting the experimental equipment to the PC host computer, and supplies power to the ARM lower computer. The motor power supply switch is the motor power supply voltage level (5V /12V) switching button, the power switch is the main switch of the test box.

Since the experimental teaching system of automatic control theory based on a portable manipulator disclosed in this embodiment is designed for the teaching of automatic control theory courses, the analysis methods of automatic control theory courses mostly use graphic methods, such as system response, root locus, frequency characteristics, a large number of curves need to be drawn, so in addition to the experimental device, the host computer platform is also released to assist teaching.

As shown in Figure 7, the experiment selection unit of the host computer platform assisted teaching is used to select the required experiment before the experiment; the parameter modification unit: before the experiment starts, the students must fill in the corresponding experimental parameters in the parameter modification box, If not filled, the default parameters will be used; data calculation unit: analyze and calculate the real-time data returned by the lower computer, calculate and analyze the received real-time information, and convert ordinary data into symbol information applied by automatic control theory. It is convenient for students to watch and understand; data display unit: students can not only observe the experimental phenomenon on the spot, but also quantitatively observe various real-time data of the experimental system through the host computer platform. In addition, this unit will also display the real-time curve of the controlled object on the upper displayed in the computer software; experimental control unit: control the progress of the experiment, the experiment can be started, stopped, and ended at any time, and after the experiment is over, the previous experimental data can be called for observation and comparison; communication unit: responsible for communicating with the experimental device Real-time communication, while sending control commands, it also receives data information returned by the experimental device.

Auxiliary teaching function of host computer platform:

(1) Control the experimental device to conduct experiments: use the host computer to send control commands to the experimental device. The start, pause, and end of the experiment, the selection of the control algorithm, and the readback of the parameters are all controlled through the host computer platform, and the experimental device completes the experiment by receiving the control commands from the host computer.

(2) Displaying experimental curves and analyzing experimental data: Due to the characteristics of the course of automatic control theory, drawing is a must-achieve function of the host computer platform. The upper computer platform receives the experimental data returned by the experimental device, such as the angle and position of the mechanical arm, sorts it out through calculation, and displays it to students in the form of curves and data tables to achieve good teaching results.

The control strategy of the upper computer includes:

From the mathematical model of the DC motor of the portable manipulator, the closed-loop pole without adding a controller can be obtained. In order to optimize the static and dynamic characteristics of the system and improve the control effect, it is necessary to add a control algorithm to the system. The control algorithm includes:

As shown in Figure 8, PID controller design: the mathematical model of the control system, the control law is:

Therefore, in the PID control experiment, a total of three parameters were designed, namely K _p , T _I , T _d . When conducting experiments, by modifying these three parameters and making comparisons, it can be obtained that the proportional-integral-differential link plays a role in the controller.

Lead-lag controller design: Similar to the PID control experiment, in the lead-lag control experiment, a total of 3 parameters were designed, namely K, T _i , T _d . During the experiment, students can modify the parameters of the controller through the host computer control platform, and obtain the function of the lead-lag controller by using different control parameters.

Custom algorithm design: In this module, students can verify whether the algorithm they write can achieve a good control effect. By writing their own algorithm into the host computer, running the program, and analyzing the relevant dynamic and static performance indicators from the obtained curve, the You can get the parameters to measure the control performance of the algorithm, and verify your own control algorithm by modifying it.

Root locus correction experiment: By designing the transfer function of the correction network, the performance index of the system can meet the given requirements, including series lead correction and series lag correction.

The frequency method correction experiment is similar to the root locus. By designing the transfer function of the correction network, the performance index of the system can meet the given requirements, including series lead correction and series lag correction.

In the pole allocation experiment, through the analysis of the original system, the stable poles and zero points of the system are obtained, and the pole allocation method is used to configure the system to make the system meet the given goal.

Linear quadratic final control algorithm control experiment, including LQR control algorithm, simulation of LQR controller, elimination of steady-state error and actual control of LQR controller.

Experiment example 1: PID experiment

Based on the automatic control theory PID experiment teaching method realized by the automatic control theory experiment teaching system based on a portable mechanical arm, the method comprises the following steps:

Step 1: Connect the experimental equipment to power, and connect the host computer and the host computer operating system through the USB interface.

Step 2: Open the upper computer operating system.

Step 3: The system is initialized, including the selection of the serial port, communication rate, data bits, etc.

Step 4: Select the PID experiment, configure K _p , T _I , T _d three parameters, click to start the experiment, and the system starts to run. At this time, an experimental curve representing the angle of the mechanical arm will pop up. Observe the trend of the curve to see if the system tends to Stable, if it is unstable, return to the previous layer, reconfigure the parameters and conduct experiments until the system is stable.

Experimental Example 2: Lead Lag Experiment

Based on the automatic control theory lead-lag teaching method realized by the automatic control theory experimental teaching system based on a portable mechanical arm, the method comprises the following steps:

Step 1: Same as above

Step 2: Same as above.

Step 3: Same as above.

Step 4: Select the lead-lag experiment, configure the three parameters K, T _i , T _d , click to start the experiment, and the system starts to run. At this time, an experimental curve representing the angle of the mechanical arm will pop up. Observe the trend of the curve to see if the system tends to Stable, if it is unstable, return to the previous layer, reconfigure the parameters and conduct experiments until the system is stable.

The specific description above controls the purpose, technical solutions and beneficial effects of the invention in further detail. It should be understood that the above description is only a specific embodiment of the present invention and is not used to limit the protection of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. An automatic control theory experiment teaching system based on a portable mechanical arm is characterized in that: it comprises a controlled object, a controller, an actuator and a feedback device, forming a complete closed-loop control system loop; The controlled object is a nested combination of a mechanical arm and a DC motor, which is used to generate an angular position signal; the angular position of the mechanical arm is the controlled object S, where S(r) is the reference position, that is, the target position, and S(t) is the current position of the robotic arm, that is, the actual position; The controller is used to correct the mathematical model of the system; the controller adjusts the static and dynamic characteristics of the system according to the control algorithm of the control system, which is the research content of the automatic control theory experiment teaching system; the control algorithm of the control system adjusts the static and dynamic characteristics of the system by the PC upper computer Software programming implementation; The actuator is a DC motor, which controls the rotation of the mechanical arm and realizes the position control of the mechanical arm; the characteristics of the DC motor are regarded as fixed after leaving the factory, and the mathematical model of the DC motor is determined by its own electrical characteristics; The feedback device adopts unit negative feedback, which is used to detect the actual angular position signal of the mechanical arm, and returns the signal to the controller; the feedback device is preferably realized by a photoelectric encoder; The angular position of the DC motor is taken as the research object of the automatic control theory experiment teaching system; in order to observe the experimental results more intuitively, a mechanical arm is connected to the output shaft of the DC motor as an indicator of the position of the motor; use the controller to adjust the angle of the mechanical arm position control. 2. A kind of automatic control theory experiment teaching system based on portable manipulator as claimed in claim 1, it is characterized in that: described controller comprises PC upper computer and ARM lower computer; Wherein, ARM lower computer comprises MCU master Control module, USB serial port transmission module, motor drive module and feedback device; MCU main control module adopts low-cost ARM control chip, responsible for initialization and control of all other peripheral circuits, responsible for driving DC motor rotation, and receiving position feedback from photoelectric encoders device signal, and send the obtained results to the PC host computer platform through the USB serial port module; the USB serial port transmission module can be used as the ARM lower computer to provide power, and is the data transmission interface between the ARM lower computer and the PC upper computer; the motor drive module , the linearly amplified drive circuit of the manipulator adopts a dual-channel PWM drive voltage, and the drive signal is obtained through the timer/counter that comes with the ARM control chip to drive the forward and reverse rotation and stop of the motor. At the same time, a protection drive is also designed. The circuit logic protects the circuit; the feedback device is used to detect the actual angular position signal of the manipulator and feed it back to the MCU main control module. The feedback device is the feedback part of the entire automatic control theory experiment teaching system. 3. A kind of automatic control theory experiment teaching system based on portable manipulator as claimed in claim 2, it is characterized in that: described DC motor mathematical model is: according to the electric characteristic of DC motor, the position model of DC motor It is divided into two parts: the speed model and the position integration link. First, the speed model is obtained through the identification algorithm, and then combined with the position integration link to obtain a complete position model; through the above modeling method, the open-loop mathematics of the position system of the DC motor can be obtained Model, in order to calculate the two parameters of T _m and K _e , the speed control of the DC motor is taken as the research object, because the model corresponding to the speed control of the DC motor is a standard first-order model Among them, T _m is the standard time constant of the position system, assuming that the speed of the system when the speed is stable in a step response is t, when the system speed reaches 0.632t, the corresponding time is T _m ; where U _f represents the dead time in the position system The unknown time-varying nonlinear friction disturbance torque in the area is equivalent to the voltage at the input terminal, y represents the position of the motor, v represents the speed, let T _m be the time constant of the DC motor, K _e is the speed feedback proportional coefficient of the motor, where T _m , K _e are the electrical characteristic constants of the position system, and U _f is the equivalent voltage of the nonlinear dead zone of the system. When the hardware system is established, the software compensation of the DC drive is performed on the dead zone, so that the position model of the DC motor is obtained as It can be seen that the position system is a standard second-order system. According to the step response curve of the motor position control, the parameter K _e is calculated; after many experiments and calculations, the two parameters of the system T _m and K _e are finally obtained as 0.15, 0.56, therefore, the DC motor position model is 4. A kind of automatic control theory experiment teaching system based on portable manipulator as claimed in claim 1 or 3, it is characterized in that: described controller comprises PC upper computer and ARM lower computer; First the voltage of PC upper computer The signal is transmitted to the MCU main control module through the USB serial port transmission module, and the internal timing/timer of the ARM control chip generates a square wave with a controllable duty ratio to drive the DC motor and drive the mechanical arm to rotate; the angular position signal of the DC motor passes through the two feedback devices. The feedback signal is transmitted to the MCU main control module, and the rotation direction and angular position of the mechanical arm are judged through the internal counter and phase logic analysis of the ARM control chip, and finally the angular position signal is transmitted to the PC host computer for the calculation of the voltage signal value in the next step. The front-end display module shows that at the end of the experiment, the rotation of the DC motor drives the rotation of the robotic arm to achieve the final stability of the robotic arm. 5. A portable mechanical arm-based automatic control theory experiment teaching system as claimed in claim 1, 2 or 3, characterized in that: the shape is preferably boxed, and the controller, actuator and feedback device are all packaged , using a modular design idea, leaving only the interface to interact with the outside, designing a dial on the top of the box, the DC motor is fixed inside the box, and the output shaft of the DC motor protrudes from the top of the box and is connected to a pointer ; The connection relationship of the hardware space position: the boxed experiment box is used to package the equipment, the connecting wires needed for the experiment can be stored in the storage room, the dial is used to display the rotation angle of the mechanical arm, the pointer is used to display the mechanical rotation, and the DC power plug The hole is an optional DC 12V power supply socket for the DC motor. The USB data interface/DC power supply connection port is the interface for connecting the experimental equipment to the PC host computer, and supplies power to the ARM lower computer. 12V) switch button, the power switch is the main switch of the test box. 6. A kind of automatic control theory experiment teaching system based on portable manipulator as claimed in claim 5, it is characterized in that: PC upper computer platform assisted teaching: the experiment selection unit of upper computer platform assisted teaching is used for must before experiment Select the desired experiment; parameter modification unit: before the experiment starts, students must fill in the corresponding experimental parameters in the parameter modification box, if not filled in, the default parameters will be used; data calculation unit: the real-time data returned by the ARM lower computer Carry out analysis and calculation, calculate and analyze the received real-time information, and convert ordinary data into symbol information applied by automatic control theory, which is convenient for students to watch and understand; data display unit: students can not only observe experimental phenomena on site, but also The real-time data of the experimental system can be quantitatively observed through the host computer platform. In addition, the unit will also display the real-time curve of the controlled object in the host computer software; the experimental control unit: controls the progress of the experiment, and the experiment can be performed at any time Start, stop, end, or after the experiment is over, call the previous experimental data for observation and comparison; communication unit: responsible for real-time communication with the experimental device, sending control commands and receiving data information returned by the experimental device. 7. A kind of automatic control theory experiment teaching system based on portable mechanical arm as claimed in claim 6, is characterized in that: the control strategy of described PC upper computer comprises: PID controller design: the mathematical model of the control system, the control law is: $\mathrm{<span\; class="notranslate">\; u</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; \&lsqb;</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\mathrm{<span\; class="notranslate">\; T</span>}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&rsqb;</span>\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span><span\; class="notranslate">\; \&lsqb;</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\mathrm{<span\; class="notranslate">\; T</span>}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&rsqb;</span>\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\mathrm{<span\; class="notranslate">\; T</span>}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; I</span>}}}\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; e</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>$ Therefore, in the PID control experiment, a total of 3 parameters were designed, namely Kp, Ti, Td; during the experiment, by modifying these three parameters and comparing them, we can get the role of the proportional integral differential link in the controller; Design of lead-lag controller: Similar to the PID control experiment, in the lead-lag control experiment, a total of 3 parameters are designed, namely K _p , T _I , T _d ; during the experiment, students can control the platform through the PC upper computer. Modify the parameters of the controller, and obtain the function of the lead-lag controller by using different control parameters; Custom algorithm design: In this module, students can verify whether the algorithm they write can achieve a good control effect. They can convert the program they write into a dynamic link library (.dll) format and upload it to the PC host computer, and run the program. By analyzing the relevant dynamic and static performance indicators in the obtained curve, you can get the parameters to measure the control performance of the algorithm, and verify your own control algorithm by modifying it; Root locus correction experiment: By designing the transfer function of the correction network, the performance index of the system can meet the given requirements, including series lead correction and series lag correction; The frequency method correction experiment is similar to the root locus. By designing the transfer function of the correction network, the performance index of the system can meet the given requirements, including series lead correction and series lag correction; In the pole configuration experiment, through the analysis of the original system, the stable poles and zero points of the system are obtained, and the pole configuration method is used to configure the system to make the system meet the given goal; Linear quadratic final control algorithm control experiment, including LQR control algorithm, simulation of LQR controller, elimination of steady-state error and actual control of LQR controller The DC motor modeling experiment, through the acquisition and data analysis of the angle position of the DC motor when it starts, obtains the model parameters of the DC motor from specific experiments. 8. A kind of automatic control theory experiment teaching system based on portable mechanical arm as claimed in claim 7, is characterized in that: the automatic control theory PID experiment teaching method, comprises the steps, Step 1: Connect the experimental equipment to power, and connect the lower computer and the upper computer operating system through the USB interface; Step 2: Open the host computer operating system; Step 3: The system is initialized, including the selection of serial port, communication rate, data bits, etc.; Step 4: Select the PID experiment, configure K _p , T _I , T _d three parameters, click to start the experiment, and the system starts to run. At this time, an experimental curve representing the angle of the mechanical arm will pop up. Observe the trend of the curve to see if the system tends to Stable, if it is unstable, return to the previous layer, reconfigure the parameters and conduct experiments until the system is stable. 9. A kind of automatic control theory experiment teaching system based on portable mechanical arm as claimed in claim 7, is characterized in that: the automatic control theory lead-lag experiment teaching method comprises the following steps, Step 1: Connect the experimental equipment to power, and connect the lower computer and the upper computer operating system through the USB interface; Step 2: Open the host computer operating system; Step 3: The system is initialized, including the selection of serial port, communication rate, data bits, etc.; Step 4: Select the lead-lag experiment, configure the three parameters K, T ₁ , and T ₂ , click to start the experiment, and the system starts to run. At this time, an experimental curve representing the angle of the mechanical arm will pop up. Observe the trend of the curve to see if the system tends to Stable, if it is unstable, return to the previous layer, reconfigure the parameters and conduct experiments until the system is stable. 10. A portable mechanical arm-based automatic control theory experiment teaching system according to claim 1, 2 or 3, characterized in that the feedback device is preferably realized by a photoelectric encoder.