The Research Of Fuzzy Control Method For Under-Actuated Robot And An Application Development

The under-actuated robot is a kind of robot that the independent control inputs are less than its degrees of freedom. By reducing the driven units, without affecting the main features of the case, the under-actuated robot can simplify the structure and reduce costs effectively. Beside this, it can also meet the weight, volume and reliability requirements in aerospace, deep-sea exploration, disaster relief and other special areas. As the under-actuated robot research began relatively late, the basic theoretical system has not been completed. The existing researches mostly focus on the special designs. according to different demands. A unified reference or description method is needed. In the field of control systems, due to the non-linear characteristic of the under-actuated system, the analysis and solution become more complicated. The study of this paper is divided into two main parts, the theoretical analysis and the practical design. The theoretical analysis consists of machinery analysis and control method analysis. In the design section an under-actuated manipulator which is driven by parallel pneumatic circuit are presented. Major works are as follows. First of all, the existing of some common principles of under-actuated robot has been analyzed, and the motion rules and characteristics have been discussed. A new viewpoint that the under-actuated process bases on the re-allocation of the driving forces and the motion pairs has been proposed. And the concept of the under-actuated robot has been amended based on these studies.Secondly, because of the completely free passive joints, the under-actuated robot modeling is complex. So the fuzzy control method is introduced to solve this problem. A speed fuzzy controller of a 2R robot has been given as an example. The Matlab simulation result shows that the fuzzy controller is practicable, but because of the lack of empirical data, the controller parameters also need to be optimized.Finally, the design of an under-actuated manipulator which is driven by pneumatic circuit has been finished. The parallel circuit acts as a single-input and multiple-output differential mechanism. The mechanical design and the circuit design are introduced, and the manipulator has been modeled by Onespace. The movement pattern was discussed and simulated in Matlab. In addition, the forces act on a finger were calculated and carried out by the Maple graphical representation. The behavioral data of this manipulator can be draw from these works.