Three-loop Controlled Robotic Integrated Joints And 2-DOF Light-weight Robot

Although traditional industrial robot is still widely used in industrial manufacturing, it can not answer people’s higher request in manufacturing, living, entertainment, health care, serving and so on. The robot is request to be lighter, more integrated and more intelligent, and furtherly can be collaborate with human. The integrated joint light-weight robot is integrated with driver-control board and multi-sensors inside and more compact in mechanical design as well as less weight. It is more intelligent and safer, and can complete complicated tasks and collaborate with human using the torque control, neural network control, machine learning etc. control method based on sensor fusion. But the exsiting robot products can olny reallize a limitted intelligent control since they are normally integrated with torque sensor and position sensor only. On the other hand, both the absolute encoder and torque sensor are so expensive that it highly increase the cost of the robot. The main work of this article is to build a prototype of a integrated joint and using the incremental ecoder as well as flash write method to abtain the absolute position of the robot joint, witch can reduce the cost of the robot in some degree. Additionally, 2-DOF integrated light-weight robot is built and simple control of the robot using host on PC is reallized. Based on the work of this paper, it is expected that the robot joint is integraed with more sensors and can be reallized intellegent control.Based on the analysis of mechanical, performance and elecrical parameters of the existing robot, the mechanical, performance and electrical parameters of the integrated joint in this article can be determined. The mechanical structual of the 2-DOF robot, mechanical structual of the integraed joint, permanent magnet synchronous motor(PMSM), driver board and cotrol board is designed based on the above parameters. Researches on PMSM vector control is done on the integrated joint prototype. The three loop control method witch cantain current loop, speed loop and position loop is used, and experiments and analysis is done in each loop. Feedforward controller is used in the position loop, experiments with and without feedforward controller is done and the comparision resualt is given. In order to solve the problem that the absolute position can not be obtained by incremental encoder on the power up stage, a method that using the six phase incremental encoder as well as flash wirte in DSP is proposed. The proposed method can realize minimal 15 degree small sector initialization of the integrated joint. Experiments is done to verify the effectiveness and accuracy of the proposed method. A visual host program based on MFC is written on PC is used to control the assembled 2-DOF intregrated joint light-weight robot prototype by RS232 bus communication.The 2-DOF integrated joint robot prototype in this article is designed with the modular design idea. The PMSM is designed based on the joint structure and is embeded into the joint. The driver board and control board is integrated into the joint as well, and the joint is designed as hollow structure for wiring. Using the incremental encoder to reallized the small sector initialization and abtain the absolute position of the joint. The 2-DOF integrated joint light-weight robot is compact and easilly assembled.