Dynamic Modeling And Control Of Flexible Robotic Systems

Aspects related to the dynamics and control of lightweight high speed roboticmanipulators are discussed in this dissertation. A dynamic model for an n-link spatialmanipulator carrying a payload at its end is derived. The proposed model is applicablefor robot arms that have multiple rigid links, flexible links or a combination of bothtwo types of links.The Lagrangian approach in conjunction with the finite element technique isemployed in deriving the equations of motion where the flexible links are treated asEuler-Bemoulli beams. The effects of lateral and transverse vibration on the dynamicbehavior of the manipulator are presented. In addition, the model accounts for thedynamics of the payload as well as the associated coupling effects. Furthermore, theeffects of gravity due to link rigid body motion and superimposed deflection motionare accounted for.Our model is presented in such a way that renders the application of availablecontrol techniques an easy task. The control objective in this work is to derive themanipulator to a desired set values of the joint angles starting from arbitrary initialcondition. Two controllers have been suggested to achieve this control objective. Thefirst controller applies classical control techniques of the proportional-derivative (PD)type. The second one, on the other hand, applies the more recent approach of fuzzylogic control (FLC).A comparison study between the performance of the two suggested controllershas been implemented. The study has shown that the PD-controller as compared to FL-controllers can not accurately handle the problem of control of such complex models.Soft computing tools of the fuzzy logic is shown to be a powerful tool for addingautonomy to our model. In an effort for reducing the size of the fuzzy rule base, thefuzzy control action is distributed between two fuzzy controllers, one for joint anglecontrol and the other for endeffector control.To illustrate the effectiveness of the proposed techniques an illustrativenumerical example has been simulated for a three-link manipulator with the last linkbeing flexible. Results have been generated and analyzed. Conclusions andrecommendations for future works are addressed.