Parallel robots that use closed kinematic chains have interesting mechanical properties, such as stiffness, high precision, and good load capacity, at the cost of an increasing complexity in designing and solving their kinematics. This paper proposes a design procedure and develops a prototype parallel mechanism for a teleoperator.

After introducing general approaches to the design of parallel mechanisms, section 2 analyzes such mechanisms, with three prismatic and four spherical joints, using screw theory. The authors organize such parallel mechanisms into four groups, considering that a change in axes directions or angle values gives rise to many variants.

Section 3 discusses how to choose the right design according to the application. Since teleoperation is the application, one or two combined manipulators with a large workspace is the proposed solution.

After developing the inverse and forward kinematics, the manipulator is implemented. Section 4 presents a prototype and simulation results. Considering that the teleoperator is manually moved, there is no way to check whether the robot is really following a wanted trajectory; only qualitative results are reported.

As stated in the conclusion, the paper shows how to feasibly design parallel mechanisms to obtain a new teleoperator that has the advantages of parallel mechanisms. The real utility of this teleoperator has to be demonstrated in real medical and surgical applications.

It is worth noting that some parallel and serial mechanisms are already available and used in surgery. Why not compare some of them with the proposed solution? In conclusion, the paper will interest designers of parallel robots more than researchers interested in their applications.