In one embodiment of the invention, a robotic arm is provided including a linkage assembly and a strap drive train. The linkage assembly includes first, second, third, and fourth links pivotally coupled in series together at first, second, and third joints to define a parallelogram with an insertion axis. The strap drive train includes first and second sets of straps coupled to the linkage assembly. As the linkage assembly is moved about a pitch axis, the first set of straps ensures the third link maintains the same angle relative to the first link, and the first and second set of straps ensures the fourth link maintains the same angle relative to the second link.

A damper pulley manufacturing method includes an arranging process in which a circular hub having a cylindrical outer peripheral surface and a circular pulley having a cylindrical inner peripheral surface are arranged such that the cylindrical outer peripheral surface opposes the cylindrical inner peripheral surface, a centering process in which a tapered portion of a first centering jig is made to abut on an axial end portion of the hub and a tapered portion of a second centering jig is made to abut on an axial end portion of the pulley to perform centering of the hub and the pulley, and a press-fitting process in which after the centering process, a damper rubber is press-fitted between the cylindrical outer peripheral surface and the cylindrical inner peripheral surface.

In one embodiment of the invention, a robotic arm is provided including a linkage assembly and a strap drive train. The linkage assembly includes first, second, third, and fourth links pivotally coupled in series together at first, second, and third joints to define a parallelogram with an insertion axis. The strap drive train includes first and second sets of straps coupled to the linkage assembly. As the linkage assembly is moved about a pitch axis, the first set of straps ensures the third link maintains the same angle relative to the first link, and the first and second set of straps ensures the fourth link maintains the same angle relative to the second link.