Design and Control of 5 Axis CNC Machine Based on Stewart Platform Parallel Robot Motion Mechanism

Industrial automation technology in the last few decades has been developed, it is supported by the robotics technology. Robot’s high accuracy, fast, and safe work ability, make industrial processes more productive. There are two types of robotic structure, serial and parallel structures. Parallel robots structures are less studied, developed, and used in industry compared to serial structures even though there are several advantages of parallel robots structures. Parallel robots structures have kinematic configurations with closed chain types, it means that each arm is connected to the origin. This parallel structures give better performance compared to serial structures in accuracy, acceleration at high speeds, and high stiffness. In this study, a Stewart platforms parallel robot was developed as a motion mechanism for 5 axis CNC (Computer Numerical Control) machines. This robot is expected to be able to track the trajectory which is expressed in the G-Code program. The G-Code program as a standard programming structure used on CNC machines is used as references for robot motion patterns. By doing this research, it is expected that Stewart platform parallel robot can be optimized as motion mechanism of CNC machines. The study is well done and produce a mechanical construction of 5 axis CNC machine based on Stewart platform parallel robot motion mechanism, electrical control system with linear variable resistor sensor and prismatic actuator, and also produce Python language based G-Code interpolation algorithm and PID (Proportional Integral Derivative) Cascade control system algorithm. Testing of 5 Axis CNC Machine following a square trajectory shows the good result with 0.7 mm at x axis, 1,3 mm at y axis position error in average on coordinate space and 1.09 mm actuator length error in average, and also 1,8 mm/s actuator length velocity error in average. Key Words: Stewart platform, parallel robot, 5 axis CNC