General Description 

PTER is overactuated, as there are four actuators and two degrees of freedom. This allows greater control flexibility. Presently PTER utilizes electromechanical dry friction brakes / clutches to couple link A to the base (brake 1), link B to the base (2), linksA and B directly (brake 3), and links A and B inversely (as link A moves clockwise link B is forced counter clockwise and visa versa) (brake 4). (See figure 1, 2 & 3). As can be seen in the present configuration, the brakes are directly connected to the links and never make a full revolution. The brakes / clutches turn at erratic slow speeds, often switching directions.