THREE-AXIS ROBOTIC JOINT USING FOUR-BAR LINKAGES TO DRIVE DIFFERENTIAL SIDE GEARS

A robotic joint configured as a 3-axis joint. The joint includes an input roll assembly and a pitch-output roll assembly. The pitch-output roll assembly includes: a housing; a differential mechanism including left and right input gears, an output gear, a cross element interconnecting the gears, and a clevis supporting the gears and the cross element; a left four-bar linkage coupled to the left input gear; a right four-bar linkage coupled to the right input gear; and first and second linear actuators connected to the left and right four-bar linkages. The first and second linear actuators selectively drive the left and right input gears to rotate the output gear about an output roll axis and to rotate the cross element about a pitch axis passing through the cross element and input gears. A linear actuator in the input roll assembly rotates the pitch-output roll housing about an input roll axis.