Geared robot manipulators with a jointed unit: Kinematic analysis and its application

An efficient and systematic methodology for the kinematic analysis of geared robot Ž . manipulators GRMs with a jointed unit is presented. It is shown that, by decomposing mechanical transmission lines of a GRM into serially connected jointed and disjointed units, kinematic relation between local inputs and local outputs of admissible jointed units can be systematically formulated. Accordingly, angular displacements of input links with respect to their associated primary links can be symbolically expressed in terms of joint angles by a unit-by-unit evaluation procedure. This unit-by-unit evaluation procedure provides better kinematic insights into how input torques are transmitted to various joints. It is also shown that an actuator in a GRM with a jointed unit can drive nonconsecutive joints by proper design of its gear train. A 3 degrees of freedom GRM with a jointed unit is used as an illustrative example.