A slave servo loop including an electrical amplifier, a flow control servo valve and a slave actuator connected between the control valve and a slave member is responsive when energized to a difference in the orientations of the slave member with respect to a master member for maintaining the slave member in alignment with the master member. A master servo loop is also provided including the aforementioned electrical amplifier, the aforementioned flow control servo valve, and a master actuator connected between the output of the control valve and the master member in a polarity to oppose, when energized, movement of the master member which produces movement of the slave member. On start-up of the manipulator, a lock valve connected in the lines between the control valve and the slave actuator hydraulically locks the slave actuator and hence the slave member. Any desynchronization of the slave member with the master member is eliminated by energization of the master servo loop which brings the master member into correspondence with the slave member. When the master member is substantially in alignment with the slave member, the slave lock valve is energized and allows the slave member to follow the movements of the master member.
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