Parallel kinematic mechanisms with decoupled rotational motions

A method of controlling a parallel kinematic (PK) mechanism having at least pitch and yaw rotational degrees of freedom between a handle and a frame, method comprising:

• grasping and manipulating a handle wherein the handle is connected to an input joint by two or more independent paths for transmission of motion from the handle to a frame, wherein the independent paths include a first path and a second path;
• pivoting a first intermediate body in the first path that is connected to the frame by a first connector comprising a first pivot joint, wherein the first intermediate body is coupled to the handle by a third connector comprising a third pivot joint;
• pivoting a second intermediate body in the second path that is connected to the frame by a second connector comprising a second pivot joint, wherein the second connector is coupled to the handle by a fourth connector, wherein the fourth connector comprises a flexible torsion shaft, wherein the first connector and the fourth connector both allow rotation in a pitch rotational direction about a pitch axis and restrict rotation in a yaw rotational direction about a yaw axis;
• further wherein the second and third connectors allow rotation in the yaw rotational direction about the yaw axis and restrict rotation in the pitch rotational direction about the pitch axis;
• and
• wherein the handle moves relative to the frame about a virtual center of rotation at an intersection of the pitch axis and the yaw axis that is within the handle.