Improving Transparency of Teleportation Systems in the presence of flexibility in Slave Robot
In teleoperation systems two robots (named as master and slave) is used to the indirect manipulation of an object. In certain application such as Minimal Invasive Surguery (MIS) or space, the desire is to use thin and lightweight manipulators. Surgical robots use thin links that reduce the size of the surgical incision. As a result of this technique, the size of trauma to tissues decreases and the patient will suffer less pain and will recover fast. However the space robots are designed to be lightweight and compact for minimum liftoff cost and energy consumption during robot control. One of the major problems while using a lightweight manipulator as slave robot is flexibility. A teleoperation system with reliable transparency can extend the application range of MIS or space robots to more complicated procedure. The Transparecy of teleoperation system will be affected by flexibility, while using lightweight manipulator as slave robot because of the bending and vibration of the flexible links during a maneuaverIn this thesis, the control and improving of transparency of the teleoperation system in the presence of the flexible link slave robot, is discussed. The flexible manipulator dynamic is derived on the basis of a Lagrangian-assumed mode method. A set of simulation results are provided to validate the theoretical model. The full order flexible dynamic model does not allow the determination of a nonlinear feedback control for flexible manipulators as for rigid ones, because there are not as many control inputs as output variables. This drawback is overcome by a model order reduction, based on a singular perturbation strategy, where the fast state variables are the elastic forces and their time derivatives. A composite control is adopted as follows: at First, a slow control is designed for the slow subsystem, which is shown to be the model of the equivalent rigid-link manipulator. Then a fast control is designed to stabilize the fast subsystem around the equilibrium trajectory set up by the slow subsystem under the effect of the slow control.