Abstract
It is important to save the dissipated energy of manipulators for improving the environment of the earth which is being warmed up by CO2 gas emitted from thermal power plants.
This paper describes an optimal trajectory which minimizes the dissipated energy in PTP motion of a 3-link manipulator. The two-point boundary-value problem is derived to get the optimal trajectory from Euler canonical equation. A generalized Newton-Raphson method is time-consuming to converge the optimal solution because the manipulator has many links and strong non-linearity. After using the method one time for short operating time which is liable to converge, a shooting method is applied to solve the optimal trajectory with various operating times. It is important for these iteration methods to select the starting velocity functions so as not to fall into a local optimal solution. In order to attain to a globally optimal path, this paper proposes a starting velocity function which the heavier link is accelerated toward gravitational direction and decelerated toward anti-gravitation.
It is shown from simulation that the proposed optimal path can lessen the dissipated energy in comparison to conventional path.
