Research On Schema Theory And Its Application In Control Of A Class Of Underactuated Mechanical Systems

The schema theory is regarded as the analyzing methodology for such complex dynamic systems of living beings as the mankind, etc. Originated from philosophy and developed in combination with psychology, it was applied into the artificial intelligence field in the late 1970's. Arousing great concerns, it has already become a new research direction of intellectual control. The schema theory establishes a frame of the organized knowledge structure in the human brain, abstracting typical characteristics and relations of things in a certain category. Both objective environment and general information of the incident are included. Characterized as changeable, structural and initiative, the schema theory, on the macroscopic, bridges the cognitive science with the brain theory, on the microcosm unifies the function and structure simulations of artificial intelligence. Consequently it has made significant achievements in robot controlling, neural network system and genetic algorithm, etc.The schema theory is applied here controlling a class of underactuated mechanical systems, which is a kind of non-linear systems with fewer inputs than degrees of freedom. Typical examples include the inverted pendulum system, the shoulder controlled two-link robot arm system (Pendubot), the elbow controlled two-link robot arm system (Acrobot) and three-link gymnastic robot. The controlling goal is to swing up the single or multi-level pendulum from its natural hanging position to the inverted position and keep it stable there.The main research contents of the dissertation are summarized as follows:(1) Dynamic characteristic analysis. The underactuated mechanical systems are naturally unstable and multivariable systems with strong coupling. They are characterized by dynamic unstable zero, nonholonomic and incomplete feedback linearization. Through Lagrangian dynamic analysis, system classification is carried out and the normal form set up. The structure is decomposed by breaking up the high order system into a fully actuated subsystem and an unactuated subsystem.(2) Survey of the schema concept and the schema theory, as well as their applications in robot control fields, with emphasis on Professor Zushu Li's perception-motor schema theory & Mr. Jose M C's dynamic schema hierarchy. Perception-motor schema theory can establish...