Static Power Properties of Robot Manipulators: General Formulation and Application Examples

A method for analyzing the static power properties of robot manipulators is formulated. First, a formulation for nonredundant manipulators is discussed. A power transformation matrix (PTM) constructed from a Jacobian matrix plays important roles in the formulation. The special properties of the PTM are introduced. Next, the formulation is extended for manipulators with motion and actuation redundancy. In spite of the redundancy, the relationship between the power at the hand and joints is expressed in a similar form. Then, two types of criteria for evaluating the performances of robot manipulators are defined. The first is defined based on a consideration of the sign of the power at the joints (a mix of positive and negative joint power), the second is defined based on a consideration of the possible output power at the hand under a limited joint power constraint. Finally, application examples of the criteria for 2DOF non-redundant serial manipulator and 3DOF redundant manipulator (both motion and actuation redundancies are included) are demonstrated.