Constraints satisfying trajectory tracking algorithm for the 3 dof manipulator

Abstract

The aim of this work is to solve the problem of generating signals (joint torques) forcing the anthropomorphic 3 dof manipulator to follow a path, specified in its workspace in such a way that two contradictory conditions are satisfied. Namely, the robot drives constraints are accounted for (bounded maximal torques and rotation speed limits in joint-gears) and the velocity along the path is constant. However the goal of robot control is to minimise the trajectory cycle-time. Solution to the problem results in a two-stage path design procedure. The trajectory generation algorithm is based on the known manipulator models (kinematical and dynamical). The modelling errors while trajectory tracking are controlled with the decoupled linear PD controllers of the robot-axes. The overall system including the path and trajectory planner has been simulated in order to study the role of particular constraints and to evaluate the performance of the system.