KINEMATICS OF A PARALLEL SERIAL (HYBRID) MANIPULATOR

Hybrid manipulators are parallel-serial connection robots that give rise to a multitude of highly articulate robotic manipulators. These manipulators are modular and can be extended by additional modules over large distances. Every module has a hemispherical work space and collective modules give rise to highly dexterous symmetrical work space. In this article, some basic designs and kinematical structures of these robot manipulators are discussed, the associated direct and the inverse kinematics formulations are presented, and solutions to the inverse kinematic problem are obtained explicitly and elaborated upon. These robot manipulators are shown to have a strength-to-weight ratio many times larger than the value currently available with industrial or research manipulators. This is due to the fact that these hybrid manipulators are stress compensated and have an ultralight weight, yet are extremely stiff due to the fact that the force distribution in their structure is mostly axial. The means of actuation in these manipulators are entirely prismatic and can be provided by ball-screws with antibacklash nuts or linear induction motors for maximum precision.