Study On The CMAC Based Coordinated Control Of Multidrive Systems

Coordination in complex motion control systems, such as long-distance belt conveyor driven by multiple geographically distributed electric drives or a lift and assembly task performed by multiple cooperative robots,is mandatory to the problems such as the static and dynamic balance of load, power, speed and tension among the subsystems, the smooth startup and shutdown of the whole system, the quick catch-up of robot tracking etc. Those systems characterized of nonlinear and time-varying properties are quite hard to be identified, modeled and controlled by commonly used analytical methods but it happens that those problems might fortunately be solved by the methods deduced from artificial intelligence. In the sense of control, AI algorithm is a synonymous of controller.With the preliminary study on the engineering background and some AI methods used for coordination, the author found CMAC to be a useful measure for system coordination and developed algorithms for typical complex motion control systems in his engineering project, as well as for the preparation of his dissertation.The author proposed a DCMAC+P controller that uses a main CMAC to roughly approximate the inverse of the object and an auxiliary CMAC is used to fetch up the residue error caused by the roughness of acquired inverse. This strategy is verified superior to CMAC+P controller by simulating a difficult task of a complex system composed of two servo subsystems that are required to reach speed synchronization with same periodical speed set-value but different periodically varying loads.The ASE/ACE algorithm is a different mechanism from CMAC+P and may also be used for coordinated control of complex motion control systems. It is characterized of reinforced learning that is implemented by two mutually assisted elements that the first delivers control action and the second yields a judgment used to refine the parameters of the former. To improve real-time ability of such a mechanism, CMAC is introduced into the ASE and ACE respectively to form CMAC-ASE/CMAC-ACE controllers. The simulation is performed by applying such an algorithm to the two servo subsystems of the complex system mentioned above with the results that the two independently controlled subsystems can reach synchronization quickly and automatically.With the acquired knowledge of the CMAC improved and enhanced controllers the author tried to apply them to some typical complex motion control systems as well as the systems met in the engineering project. In a robot tracking system, two CMAC based ASE/ACE controllers are applied to the tracking robot to respectively control the distance and angle relative to the escaping robot. This algorithm is verified superior in response and accuracy to common CMAC algorithm running on a reference tracking robot performing the same tracking task. In solving the power unbalance among the three AC motors cooperatively driving a long belt conveyer, DCMAC+P algorithm is used to perform APR (Automatic Power Regulation) to achieve balanced load currents of the motors with unequal operating conditions such as circuit resistances and supply voltages. Simulation validates the effectiveness of the controller, as well as the better performance than that of a fuzzy controller.An important chapter of the dissertation is concerned with the application to long distance belt conveyers driven by multiple distributed electric drive systems. To secure the success of the projects, more thorough and detailed analysis has been done in the preliminary research. Main system components such as conveyer belt, gearbox, as well as the drives with speed and current loops are modeled with special attention paid to the treatment of the viscoelasticity of the conveyer belt. Because the drive subsystems are coupled via the conveyer belt, a CMAC based ASE/ACE is used for the power balance. Simulations proved that the algorithm can obtain good system performance and solve the problem of power balance.The dissertation is ended with a summary and some problems to be solved in the future.