Study On Decentralized Control For Reconfigurable And Modular Robots

Robot abilities increase greatly as the development of robot technology, and robot applications spread into more and more fields, so people hope they can complete more complex tasks. As we know, robot can do various different tasks through programming, however, how many tasks it can realize after all is constrained to its mechanical structure. Sometimes, maybe robot can choose optimal configuration or structure with different parameters to adapt to different jobs when tasks are designated in advance. This is very possible. But robot cannot form optimal structure to finish some unpredictable, nonstructural environment or variant tasks, such as nucleus scrap heap recycle bin, cosmic space station and lunar base etc. Thus, it is very difficult or impossible to design a robot which can achieve wider task demand. Reconfigurable and modular robot emerges, it can change its kinematical and dynamical parameters due to the different environment to accommodate diverse environment and complete some more complex work. Scholars in the world have deeply studied the reconfigurable and modular robot, but focus on its automatic generation in kinematics and dynamics, kinematics calibration and distributed control. There are many challenging, just underway and marginal aspects, for example, inverse kinematics solution, uncertainty control, fault detection & diagnosis and tolerant control. These problems still need scholars pay much attention and effort. Hence, it is very necessary and significant to study further on reconfigurable and modular robot.In this paper, the kinematics and dynamics function of reconfigurable and modular robot were researched, and as the key points the control schemes based on high gain observer and fuzzy wavelet network were studied. The important content of this paper are as follows: First, the kinematics function of reconfigurable and modular robot was set up by exponential product method. Then the dynamics function was deduced by rigid body function geometry function, base on rigid body Newton-Euler function and inverted iterative of generalized force, a iterative Newton-Euler function of the sub-system was got. And the kinematics description of the reconfigurable and modular robot was laid out under the effect of force and torque.In the next place, based on the sub-system dynamic function of configurable and modular robot we have set up, the high gain observer based decentralized controller was designed, in case the states were observable, and introduce the uncertainties belong to or not belong to the model, compensate to the closed-loop system by the controller designing . Through Lyapunov stabilization theory, analysis was laid out according to the observation error and tracking error. The result of simulation also shows the feasibility of this controller designing. It is easy to design and deduce for this method, but because of the introduction of high gain observer, there will be a impact appear in the closed-loop system, so it is difficult for the application. According to this fault, the method of fuzzy wavelet network decentralized control was brought. Using this method, the system completed locus tracking and function approaching at the same time. This control method also contains updating law of parameters in the condition that system perturbation and network estimation error were bounded, and the robust term. Through Lyapunov stabilization theory, analysis was laid out according to the estimation error and tracking error. It is more complex than high gain observer decentralized control, but the adaptive ability of system was improved by the updating law, also improved the control ability of system. The result of simulation shows this method makes system not only achieve fine dynamic performance, but also complete tracking control.At last, all the work was concluded in the summary, and combining what I have learned, prospect for some questions was laid out.