Study On The Cooperative Control System Of Flexible Manipulators Based On Assumed Mode Method

The work of this dissertation is combined with "Studies on the distributed parameter model and control method for multi-link constrained flexible manipulators cooperative motion system", which is supported by China National Natural Science. This dissertation mainly research on the cooperative control system of two flexible manipulators holding a common rigid object in a horizontal workspace.With the development of the robotics, the application in each field of the robotics is more extensive, especially the application of flexible manipulator. Compare with the rigid manipulator, flexible manipulator have the trait of higher speed, lower energy consumption, lighter and nimbler. So it has more bigger operation space, high efficiency, fast response and accuracy. There are many potential advantages of flexible manipulator. The flexible manipulator occupies very important position in the field of industry, national defense, etc. With the high development of the space aeronautics and robotics, the multi-body systems, which composed of flexible components, have obtained more and more application.Recently years, modeling and control of the flexible manipulator have obtained remarkable achievement. With the development of space technology,the problem of cooperative control has arisen. In order to get more precise and skillful manipulation, the use of two or more manipulators is necessary in such various applications as material handling, assembling and large space structures constructing, etc. On the other hand, many satellites have been launched so far. Some of them have become uncontrollable and don't work in the orbits. So. replacing ihe failed parts, charging the exhausted batteries and recovering the attitude of the satellites are the desired services to rescue them. As this task in space is dangerous for the astronauts, the space robots are expected to do it. It is hard for a single manipulator to accomplish the task, so the cooperative manipulators system is required.Now the study of cooperative control has received great attention. A lot of researchers have launched extensive study and made many achievements in this field. In cooperative control of flexible manipulators, not only the position and force of the end-point but also the cooperative motion between the end-point and the object are concerned. So it is a synthesis problem of position, force, vibration and cooperative control.In this dissertation, we discussed the dynamic model and controller design of the cooperative control of the multi-link flexible manipulators, which holding a rigid object in a horizontal workspace. The flexible manipulators are considered as the Euler-Bernoulli model, for which rotary inertia and shear deformation are ignored. From the position of the manipulators and the object, we can obtain the constraint condition. Then, by using Lagrange multiplier method and the assumed mode method, the dynamic model of the cooperative control system was derived. In order to simplify the controller design, we use singular perturbation approach to divide the dynamic model into slow subsystem, which represent large range movement and the fast subsystem, which describe small range vibration. For the slow-system, a robust controller was proposed to our system which can achieves the desired configuration of the two manipulators and the desired holding force of the object. For the fast-system, a fuzzy controller is devised, which can restrain elastic vibration...