Traditional control systems suffer from significant speed and position errors. In this paper, we build a single-axis motion control system using the LM629 and LMD18200 as core components. Results show that this system significantly reduces speed and position errors, and the algorithm is simple and easy to implement. 1 Introduction Motion control refers to the transformation of computer-generated decisions based on predetermined schemes and complex environmental conditions into desired mechanical motion. Motion control mainly includes electrical motion control using motors as power sources; gas-liquid control using gases and fluids as power sources; and thermal engine motion control using fuels (coal, gasoline, etc.) as power sources. Today, with the development of microelectronics, power electronics, and microcomputer control technology, electrical motion control technology has shown unparalleled advantages. This has led to electrical motion control becoming the mainstream of motion control, giving rise to electro-hydraulic, electrical, electrothermal, and mechanical motion control technologies. Therefore, in terms of motion control, the current era is the era of electrical motion control in factories, homes, and offices. Motion control is a technology that has emerged with the development of science and technology. It can be said to have evolved from servo control technology, which is the branch of automation that is most closely linked to industry and has the widest range of services. Servo systems are key actuators in all automated control machinery that requires precise speed and positioning control, such as CNC equipment, robots, and radar tracking systems. 2 System Structure and Control Principle [IMG=Figure 1-1 Traditional Motion Control System Structure]/uploadpic/THESIS/2007/11/20071113133239225801L.jpg[/IMG] Figure 1-1 Traditional Motion Control System Structure [IMG=Figure 2-1 Experimental System Structure Diagram]/uploadpic/THESIS/2007/11/2007111313324921821O.jpg[/IMG] Figure 2-1 Experimental System Structure Diagram Motion control processes the motion of one or more control axes of a mechanical system and the coordination between these motions. It involves adjusting the speed of motion on each axis, performing motion in a certain acceleration and deceleration curve pattern, and forming accurate positioning or tracking of specific trajectories. These precise position, speed, force, and torque controls are mainly realized through motors, drivers, feedback devices, motion controllers, and main controllers. The composition of an electromechanical motion control system is shown in Figure 1-1. 3 System Implementation 3.1 Hardware Implementation The system block diagram of this design is shown in Figure 2-1. (1) The host is a PC with an ISA expansion slot. (2) The core controller structure is LM629. (3) The core driver is LM18200. (4) Position and speed closed loop is achieved through a 500-line photoelectric encoder. (5) The SAWAMURA KOGYO MM40A8 motor is selected for execution. In the experiment, a PC with an ISA expansion slot was selected as the core part of the single-axis motion control system. The control program and various control algorithms are implemented on the computer through software. This system uses an AL-01-512 photoelectric encoder as the position detection device, which directly outputs binary position code. The photoelectric encoder is the second sensor element in the system. It is connected to the DC motor rotating shaft through a gear set with a reduction ratio of 4:1. A scale is installed on the photoelectric encoder shaft, which can roughly display the angle of the photoelectric encoder. AL-01-512 is a 9-bit absolute photoelectric encoder with an output binary position code range of 0x000-0xlf, which corresponds to the output angle. 0°～360°, resolution 1LSB is 3600/512≈0.70310e. In motion control systems, photoelectric encoders are generally used as the motor shaft position acceleration control mode selection and acceleration loading flowchart [IMG=Figure 3-1 Module Flowchart]/uploadpic/THESIS/2007/11/20071113134505332622P.jpg[/IMG] Figure 3-1 Module Flowchart PID Parameter Loading Flowchart Figure 3-2 PID Parameter Loading Flowchart The detection component forms a position closed loop. The controlled object of this experimental system is the MM40A8-type motor from SAWAMURA DENKI KOGYO CO. Its characteristic is that it can often operate in stall and low-speed states, therefore it is suitable as an actuator in position or low-speed motion control systems. Its no-load speed is approximately 1000 r/min. The motor input is a voltage signal amplified by the drive circuit, and the motor's position, speed, acceleration, and torque can all be studied as controlled variables. 3.2 Core Component Introduction: The LM629 is a dedicated motion controller that integrates all the functions of a digital motion controller onto a single chip, making the design of a fast and accurate motion control system easy and straightforward. It is suitable for various DC motors, brushless DC servo motors, and other servo mechanisms that provide incremental position feedback signals. It can perform the centralized, real-time calculations required for high-performance digital motion control systems, providing 8-bit PWM modulation signals and direction signals to directly drive the bridge circuit. The component uses NMOS technology, and the maximum input clock is available in 6MHz and 8MHz versions. Its main features are as follows: (1) 32-bit position, velocity, and acceleration registers; (2) Programmable digital PID controller with 16-bit parameters; (3) Programmable differential sampling time; (4) 8-bit pulse width modulation (PWM) signal output; (5) The parameters of the speed, target position, and PID controller can all be changed during motion; (6) Two control modes: position and speed; (7) Real-time interrupt capability. The LMD18200 is an H-bridge component for DC motor drives launched by National Semiconductor (NS). It integrates CMOS control circuitry and DMOS power devices on the same chip, and can be used to form a complete motion control system with a main processor, motor, and incremental encoder. The LMD18200 is widely used in printers, robots, and various automation control fields. The main performance is as follows: (1) Peak output current up to 6A, continuous output current up to 3A; (2) Working voltage up to 55V; (3) Low RDS (ON) typically 0.3W per switch; (4) TTL/CMOS compatible level input; (5) No “shoot-through” current; 3.3 Software Implementation The driver task is to initialize the LM629 register parameters, set the acceleration, set the motion trajectory parameters and set the PID filter parameters. Then, the LM629 automatically completes the PID control of the motor according to the predetermined parameters. In the system program design, corresponding program modules are written for speed control mode selection, PID parameter loading and motion parameter loading. The flowcharts of each module are shown in Figure 3-1 and Figure 3-2. 4 Experimental Results The tuning of the control system parameters is first done by the main control computer sending the PID numbers of each channel to the control board to see if the given parameters meet the requirements of the control system. Generally speaking, the proportional coefficient increases, the dynamic response speed of the servo drive system increases, but too large a coefficient will cause system oscillation. Increasing the integral coefficient reduces steady-state error, but slows down the dynamic process and is detrimental to stability. Figure 4-1 shows the measured curves when Kp=10, Ki=5, and Kd=100 in position mode. The derivative action reflects the changing trend of the deviation signal, introducing an effective early correction signal into the system, thereby accelerating the system's action speed and reducing the settling time. Typically, only the proportional action is retained initially, and the auxiliary parameter is continuously increased until the system begins to oscillate. Then, it is slightly decreased to ensure a certain stability margin. Finally, based on the form of the position signal (step, velocity, or acceleration), it is decided whether to add integral or derivative action. Since the tuning of control system parameters is relatively complex, better PID parameters can be obtained through multiple trials. Figure 4-1 shows the effect of using all Kp, Kd, ​​and Ki. From the figure, we can see that the position and rotational speed errors have reached our expected requirements. 5 Conclusion Currently, the research methods for robot dynamics control encompass almost all control methods in control science. Due to the lack of effective hardware implementation support, most algorithms either fail to achieve the desired control effect or are simply impossible to implement. This paper presents preliminary work to address the aforementioned problems, aiming to provide an effective hardware platform for subsequent research on control methods. By programming the LM629, the PID values ​​are modified to regulate motor operation. Experimental data is obtained by selecting different values ​​under different operating modes, and these data are compared and analyzed with ideal curves to draw general conclusions. (Proceedings of the 2nd and 3rd Servo and Motion Control Forums)