Research On The Interpolation Control System Of Six-DOF Robot Manipulator Based On FPGA

The initiative of "Made in China 2025", which was proposed in March, 2015, emphasizes that "Made in China" will be no longer a low-cost production or processing. Its new guiding principles are to have manufacturing be innovation-driven, emphasize quantity, achieve green development, optimize the structure of Chinese industry, and nurture human talent. And the goal is to comprehensively upgrade Chinese industry, making it more competitive in the global industry. In the environment of World Industry 4.0(the fourth industrial revolution, a high-tech strategic plan proposed by the German government), robots are playing an increasingly important role in industrial production. Industrial robots requested more meticulous in terms of functionality and performance, which makes researches and developments of the interpolation and control system of robot manipulators more critical. Some interpolation controllers like single-chip microcomputer and ARM are limited on the calculation speed and real-time interpolation speed of interpolation algorithm, and their parallel processing ability is week. Therefore, the scheme of using FPGA(Field Programmable Gate Array) as the main chip is more suitable for motor control application fields.Based on the development and research status of domestic and foreign industrial robots, the present thesis is working on six degrees of freedom(DOF) industrial robots manipulators’ interpolation trajectory control method. The study and design of manipulator interpolation control system have been validated. The structure and control characteristics of the six-DOF manipulator have been analyzed, based on the six-DOF industrial robot IRB4400 of ABB Company. According to a D-H model is established to achieve the manipulator kinematics analysis. On the basis of thorough comparison of lines, arcs, Bezier curves, B-spline curves and NURBS(Non-Uniform Rational B-Spline), the NURBS interpolation algorithm is chosen and further studied. Considering the real-time processing of interpolation algorithm implementation, error constraints and speed planning etc., The NURBS interpolation controller is designed employing the Quartus Ⅱ 13.0 of Altera’s FPGA EP4CE22E22C8. Verilog HDL description language is used in the design. The NURBS curve interpolation controller, based on the velocity planning of S-curve adaptive control, is completed according to EDA top-down design method. C++ language is used to design the interface which using in computer. The hardware is designed with Altium Designer software, on the basis of the hardware circuit, the welding and debugging of the hardware circuit are completed.The functionality and performance of the interpolation controller are tested by the Modelsim simulator. The interpolation control system is completed via the PC interface, hardware interpolation and manipulator debugging. According to the process of time sampling interpolation, rough interpolation is calculated on the PC, the fine interpolation is finished in FPGA, Real-time data is transferred between the upper and lower machine via USB2.0. Testing results show that the control system has excellent reliability, versatility and portability.