Conceptual Design and Robust Control of a Parallel Robot for High Speed Pick and Place Applications
Parallelogram structure, high strength within limited structural volume and good dynamic behavior as well as high speed and high acceleration has made parallel Delta robot as one of the best choices in applications which involve handling small objects. In this thesis, the robot is used in its simplest structure, namely three degrees of freedom. After introducing the mathematical model and the Jacobian analysis, robot dynamics are derived based on Lagrange method. Modeling reliability is verified via a simulation of the robot in ADAMS software. Kinematic parameters of the robot are optimized according to three kinematic indices representing robot’s speed and skill, via a multi-objective optimization by NSGAII and a Pareto front of optimal parameters are provided. Moreover, trajectory of the robot’s end effecter is planned with the aim of reaching its maximum speed. By solving the inverse kinematics and dynamics and obtaining joint space restrictions on speed, acceleration and torque of actuated joints, specifications of appropriate motors are determined. Finally, a robust control algorithm is introduced to suppress parametric uncertainties in both kinematics and dynamics of the robot and the global stability of closed loop system is verified using Lyapunov second method. Simulation results demonstrate that the optimization method while used along with appropriate path and trajectory planning and proposed control algorithm leads to the largest number of robot displacements within a specified time interval, complying with the expected minimum cost and practical implementation perspectives.
|2014||M.Sc.||Parallel and Cable Robotics|