Hydraulic drive system has high powerweight ratio and durability, but it cannot be used in interactive control system because of its nonlinearity and high output stiffness, especially in the field of robots. A force/moment control strategy was proposed, and a robust internalloop compensator (RIC) for hydraulic actuators was designed. By decoupling the internalloop compensator and the outerloop controller, the force/moment control problem was simplified to a motion control problem. A motion feedback strategy for the connecting rod end was proposed. The output torque feedback controller of the actuator was established by means of the crossparallel connection of torsion springs. The experimental results show that the designed HEA based on the nonlinear robust inner loop compensator has the characteristics of torque controllability, reversible drive and strong robustness.