A robotic tool changer for machining center includes a drive mechanism, a first motor, and a rotary seat which are mounted on a body. The drive mechanism includes a first rotating shaft, a second rotating shaft, a first swing arm, a second swing arm, and a linkage member. The first rotating shaft and the second rotating shaft are arranged in parallel. The first swing arm is connected to the first rotating shaft while the second swing arm is connected to the second rotating shaft. Two ends of the linkage member are pivotally connected to the first swing arm and the second swing arm respectively. An end of the second rotating shaft is fixed to the rotary seat. Thereby, when the first motor drives the first rotating shaft to rotate, the rotary seat is driven to turn over. Thereby, with the configuration of the first motor and the drive mechanism, the hydraulic oil leakage and the environmentally unfriendly subsequent treatment of the hydraulic oil when the hydraulic cylinder is used as a power source can be improved.

An actuator system having a controlled element configured for rotary movement about a first axis relative to a reference structure; a linkage system between the element and reference structure; a first actuator and a second actuator configured to power a first degree of freedom and an independent second degree of freedom of the linkage system, respectively; the linkage system having a first link configured for rotary movement about a second axis not coincident to the first axis and second link configured for rotary movement about a third axis; the linkage system configured such that a first angle of rotation may be driven independently of a second angle of rotation between said first link and said reference structure; wherein one of the first or second actuators is configured and arranged to drive rotation of the element about the first axis when the other is operatively locked.