An industrial robot and a control system therefor are described. The robot generally consists of a base member, a post member rotatably mounted on the base member, fluid actuated means for rotating the post member relative to the base member, an arm assembly mounted on the post member, means for performing a work function mounted on the arm assembly, fluid actuated means for operating the arm assembly and the work performing means and a system for controlling the operation of the fluid actuated means. A fluid reservoir is provided having a compartment in the post member, and fluid lines intercommunicate the reservoir and the aforementioned fluid actuated means. A motor driven pump mounted on the post member supplies fluid from the reservoir under pressure to the fluid actuated means under the control of electrically operable valves mounted on the post member for that purpose. A control system operates to control the aforementioned hydraulic system by sensing positions of the robot mechanism and comparing those sensed positions with desired positions, information concerning which is in a storage element. The desired and actual positions are compared in a first comparator for producing an error signal which forms a reference signal. The reference signal along with signals corresponding with the actual and desired positions are compared in a second comparator to produce a second error signal which ultimately causes the robot mechanism to move by the desired amount.