Trigonometric S-curve based trajectory planning algorithms for precise handling applications of robotic manipulator

Abstract

Robotic Manipulator is an essential motion subsystem component for positioning and orientating object for the specified task and is now more than a machine. Automated trajectory planning of robotic manipulator is a significant feature towards building the applications for the factories of the future. Trajectory planning of industrial robots is influenced by variables such as motion descriptions, nature of application, robot anatomy, joint capabilities, presence of obstacle, optimality criteria and trajectory interpolation scheme. When the jerk limits are not considered by the trajectories, inaccurate positioning, unwanted residual vibrations and premature wear of actuator and robot structure occur, which ultimately result in reduced life span of manipulator. Minimum jerk trajectories are desirable for precise handling applications due to their similarity to human joint movements and for amenability to path tracking with minimum vibrations.Limiting the jerk yields reduction of stresses to the actuators and robot structure which ensure better tracking accuracy in trajectory. In view of the above, the often required operational environments for precise pick and place moves in industrial practice are considered in this research. In this focus, the objectives of this thesis are set as: To establish trajectory interpolation scheme for six Degrees Of Freedom (DOF) articulated robot using jerk bounded Synchronised Trigonometric S-curve Trajectory (STST). To develop the trajectory planning of algorithms suitable for precise handling applications those need to operate under three different scenarios of environments for precise pick and place moves.Most widely used interpolation scheme, the cubic spline has rectangular jerk profile.