Abstract: Based on the requirements of open motion control, an open servo motor motion controller capable of high-speed and high-precision interpolation was designed with DSP and CPLD as the core. The hardware structure and working principle of the controller are introduced. The controller communicates with the host computer through PCI or USB bus, and the position loop adopts a speed and acceleration feedforward PID control algorithm. Experimental and simulation results show that the controller has good real-time control performance, small following error, and high machining accuracy. Keywords: Open motion controller, DSP, CPLD 1 Introduction Motion controllers are core motion control components commonly used in mechatronic equipment such as CNC machine tools and robots. Modern CNC technology has placed increasingly higher demands on the performance indicators of motion control systems, such as openness, real-time performance, machining speed, and accuracy. With the continuous development of integrated circuit technology, microelectronics technology, and computer technology, motion controllers have evolved from motion controllers with single-chip microcomputers, microprocessors, and dedicated chips as the core to open motion controllers based on PC platforms with a coprocessing architecture using digital signal processors (DSP) and complex programmable logic devices (CPLD) as the core processors. This approach organically combines the information processing capabilities and open nature of a PC with the powerful motion trajectory control capabilities of a motion controller, resulting in strong information processing power, high openness, accurate motion trajectory control, and good versatility. On a unified human-machine interface platform, different hardware functional modules are implemented through appropriate adjustments to DSP algorithms and CPLD configurations, facilitating easy connection with various types of drivers. Therefore, PC-based next-generation motion controllers have become the mainstream and development direction of control systems. The open motion controller developed in this paper uses a PC as its platform to complete the setting and sending of control commands such as coordinate transformation, trajectory planning, and coarse interpolation calculations. It can also display real-time parameters such as the current servo system's position, speed, and motor status. The motion controller uses a DSP chip as its core processor to complete data processing and control algorithms, handle protection interrupts, and communicate with the PC in real-time via PCI or USB bus. The CPLD chip acts as a coprocessor to acquire encoded signals, perform phase detection processing, configure and output pulse and analog quantities, internally convert the DSP-processed control data and send it to external devices, and manage the interfaces between the DSP and various external devices. This motion controller can perform non-uniform speed ratio synchronous motion control, supports NURBS interpolation, and provides a rich set of dynamic link library functions. For details, please click: Research and Development of DSP-Based Servo Motion Controller