Optimal design for energy conservation of a vertically articulated manipulator

In order to help reduce global warming, it is important to design even for a vertically articulated manipulator with 3 joints so that the dissipated energy of running gears with motor can be minimized. This paper proposes an optimal design method for simultaneously determining 8 design variables, which are the 3 motor masses, the 3 reduction gear ratios, the counterbalancer mass for the third link and the offset between the first and the second link. By using these design variables, the equation of motion and the dissipated energy can be expressed as functions of the moment of inertia and Coulomb friction torque of the joints and the inertia matrix of the manipulator. The optimal design variables can be determined by minimizing the dissipated energy under the constraint conditions for the motors and offset. An integer number of stages for the reduction gear trains are determined from the optimal gear ratios. The proposed design method can reduce the dissipated energy more effectively than an inertia matching method.