A Scissor Linkage Design and Singularity Avoidance Methods

Scissor linkage designs and methods of operation are disclosed. In one embodiment, a robotic limb includes a scissor linkage. In one embodiment, the scissor linkage includes a rotatable connection, two proximal links, and two motors configured to selectively rotate the two proximal links. Relative rotation between the two proximal links selectively controls extension, retraction, and rotation of the scissor linkage. Additional embodiments are related to scissor linkages including links designed to be have specific length relationships to avoid a singularity occurring during operation. In some embodiments, links may include torque transmissions to avoid singularities and/or to transmit torques to a distal portion of a scissor linkage for use in actuating other components including another scissor linkage arranged in series with first.