| 3 | 5 | The standard four-degree-of-freedom WAM Arm, shown in Figure 1, has four cable-driven joints labeled J1 through J4, and four brushless DC motors labeled M1 through M4. M1 controls the yaw (J1) of the WAM and is located in the base of the WAM. Using Barrett’s patented cable differential, M2 and M3 together control the pitch (J2) and roll (J3) of the WAM, and are contained in the shoulder of the WAM. M4 controls the bend of the “elbow” (J4), and is located just above M2 in the shoulder. Using Barrett’s Puck technology, all motor encoders, power amplifiers, and controllers are located in a single compact package adjacent to each motor, eliminating the need for a controller cabinet and heavy electrical cables. |
