Motion control is a comprehensive, multidisciplinary technology that has emerged from research in electric drive technology and with the development of science and technology. In today's automation technology, motion control represents the most widely used and complex tasks. The development of motion control systems can diversify and increase the complexity of drive control functions, thereby meeting new production requirements. Simultaneously, the development of motion control systems will bring production flexibility, improved product quality, and reduced equipment costs. To achieve diversified and complex drive control functions, enabling motion control systems to possess high-performance control integrating high speed, high precision, high efficiency, and high reliability, servo control is one of the fundamental and key technologies. This article demonstrates how a multi-servo control mode enables a motion control system to achieve high-performance motion control and diversified motion functions. It achieves precise reciprocating motion control of a coordinate platform and continuous uniform rotational motion control of a roller. Position/Velocity Servo Control Mode In some transmission fields, it is necessary to achieve high-precision position control for certain controlled objects while simultaneously implementing various different motion control functions for other controlled objects. A single servo control mode, whether for position servo control, speed servo control, or torque servo control, is often difficult to implement. A fundamental requirement for achieving high-precision position control of a controlled object is the availability of a high-precision actuator. AC servo systems using permanent magnet synchronous motors (PMSMs) and their servo drives as actuators can achieve extremely high position control at a relatively low cost. Furthermore, PMSMs and their drives offer multiple servo control modes, including position servo control, speed servo control, and torque servo control, effectively meeting the diverse motion control requirements of various controlled objects. In position servo control mode, the motor's positioning is determined by the number of input pulses. The motor speed is related to the pulse frequency, and the angle of rotation is related to the number of pulses. The servo drive receives position command signals (pulses/direction) from the upper-level digital control device, inputs them as pulse trains, and after electronic gear frequency division and multiplication, compares them with the feedback pulse signal in a reversible deviation counter to form a position deviation signal. The position deviation signal is then adjusted by the composite feedforward controller in the position loop to form a speed command signal. The deviation signal, after comparison with the speed feedback signal (same as in the position detection device), is adjusted by the proportional-integral controller in the speed loop to generate a current command signal. After vector transformation in the current loop, the torque current is output by SPWM to control the operation of the AC servo motor. To improve the accuracy of real-time automatic gain adjustment in position servo control mode, an adaptive gain function is added to the driver. This function essentially adds an automatic gain to minimize the stabilization (stopping) time. In speed servo control mode, the motor speed is adjusted directly by controlling the DC voltage (analog speed command) input to the servo motor driver via a potentiometer. This allows for speed adjustment between 0 and 3000 r/min, and the motor can operate continuously at a constant speed within this range. The servo driver uses a load model to estimate motor speed, thereby improving response performance and reducing vibration after stopping. A real-time speed observer is used to improve speed detection accuracy. This motion control system, combining position and speed servo control modes with servo motors and their drivers as actuators, achieves high-precision, high-speed, fast-response, wide-range speed adjustment, and high-torque low-speed control. It also enables distributed control of multiple controlled objects and multiple control functions within the same system. Application of Position/Velocity Servo Control Mode In a certain process experiment, precise reciprocating motion of four single-axis platforms and continuous uniform rotation of four other rollers were required. A single servo control mode would be difficult to achieve, and even if implemented, would require additional hardware, increasing costs. Therefore, a multi-servo control mode scheme was considered, employing both position and velocity servo control modes. Position servo control was used for the motors controlling the reciprocating motion of the single-axis platforms, while velocity servo control was used for the motors controlling the continuous uniform rotation of the rollers. System Composition This system, based on position/velocity multi-servo control, primarily consists of a PC, a motion control card (a DEC4T motion control card from MOVTEC, Germany), and permanent magnet synchronous servo motors with servo drivers. The motors using position servo control mode, after signal processing and calculation within the motion control card, send pulses and direction commands of a specific frequency to the servo drivers. The servo drivers, after PID and other control calculations, output voltage signals, generating torque to make the motors operate according to the commands. The DEC4T servo motion control card is a dedicated analog motion control card based on a PC. It connects to the PC's ASI expansion slot and controls 1 to 4 axes, with a maximum of 4 axes in 4-axis linkage. Therefore, the system can control the reciprocating motion of four single-axis platforms simultaneously by controlling the motor's operation. Figure 1 shows the servo drive principle diagram for position servo control mode. For motors using speed servo control mode, the motor speed is adjusted by regulating the given input DC voltage (analog speed command) via a potentiometer. Drift of the external analog speed command system, including the controller, is eliminated by adjusting the driver parameters. System Parameter Analysis The servo motors and drivers used for both position and speed servo control modes are from the Panasonic MINSAA series. Their main parameters are: rated output 400W, rated speed 3000 r/min, incremental encoder resolution 10000 (unit: pulse), and ball screw pitch 5mm for the single-axis platform. To determine the pulse equivalent δp of the motor in position servo control mode, i.e., the linear displacement generated by each electrical pulse load, the parameters of the driver must first be set: Pr46 (numerator of the first command pulse frequency multiplier), Pr4A (numerator multiplier of the command pulse frequency multiplier), and Pr4B (denominator of the command pulse frequency multiplier). In this system, Pr46=10000, Pr4A=3, and Pr4B=10000. The incremental encoder resolution of 10000 is denoted as F (unit: pulse), and the number of pulses required for one revolution of the motor is f (unit: pulse). Therefore, the numerator Pr46, numerator multiplier Pr4A, and denominator Pr4B of the command pulse frequency multiplier must satisfy the following: Therefore, the number of pulses f required for one revolution of the motor is f=1250 pulses, and the pulse equivalent δp=0.004mm/p can be obtained. In speed servo control mode, the motor's parameter Pr02 (control mode selection) is set to 1 (speed control mode) in the driver. Pr07 (speed monitor selection) is obtained based on 6V/rated speed. The direction and ratio of the speed command are adjustable according to the parameter settings. In this system, the servo motor parameters controlling the roller rotation are set to factory default values. By gradually increasing the Pr11 (first speed loop gain) value, abnormal noise and vibration from the motor are prevented; by gradually decreasing the Pr12 (first speed loop integral time constant), overshoot/offset is reduced to an acceptable level. Speed ​​command drift is addressed by adjusting parameter Pr52 so that the motor does not rotate when the speed command input is 0V. This system requires setting the motor running time in position servo control mode. The single-axis platform in the system has a lead screw travel of 200mm, a running speed set to 50mm/s, and an acceleration set to 200mm/s². Therefore, the acceleration/deceleration time is 0.25s each, and the distance traveled during acceleration/deceleration is 25mm; the distance traveled at a constant speed of 50mm/s is 150mm, taking 3s. Thus, one round trip by the motor takes 7s. The motor's running time can be controlled by setting the number of executions in the control program. Conclusion Permanent magnet synchronous servo motors have high efficiency and power factor, and are smaller in size than asynchronous motors of the same capacity, exhibiting excellent control performance. This system utilizes the position/speed servo control mode of a permanent magnet synchronous motor, proposing a novel control concept that integrates speed control and position control. This realizes the diversification and complexity of the motion control system's functions, while simultaneously meeting the high-performance control requirements of high speed, high precision, high efficiency, and high reliability. This system boasts a simple, compact design and reliable performance; it offers significant advantages in control precision, functionality, and anti-interference capabilities. The rationally designed system software structure also ensures its real-time performance and stability. This system provides optimal solutions for various mechatronic devices, showing promising application prospects not only in motion control but also in process control fields such as chemical engineering, materials science, and bioengineering.