Abstract: In position-disturbance type electro-hydraulic servo force application systems, the motion of the object under force introduces significant position disturbances, and the nonlinear characteristics and time-varying parameters of the system pose challenges to system correction and optimization. To address the issues of redundant torque and parameter variations, model reference adaptive control is employed based on the principle of structural invariance for compensation, and PID control is used to ensure satisfactory tracking performance. This control method effectively eliminates the influence of position disturbances while overcoming the effects of nonlinearity and time-varying parameters, thus improving the robustness and tracking performance of the system. Simulation results verify the above conclusions. Keywords: Position disturbance; Electro-hydraulic servo system; Adaptive control. Electro-hydraulic servo systems are widely used in various technical fields, and position-disturbance type electro-hydraulic servo force application systems are a complex branch within this field. A position-disturbance type electro-hydraulic servo force application system refers to a system where the object under force is a positional system, its motion determined by itself, and the force application system only plays a loading role. The load simulator used in the aerospace field is a typical example of a position-disturbance type force application system. The characteristic of this type of system is that the force-applying system applies a force function to the position system, while the position system moves according to its own laws. Therefore, the force-applying system is passively affected by disturbances in the position system. This position disturbance generates a large force interference in the force-applying system, i.e., redundant force. If not handled properly, this redundant force can be much larger than the force the system needs to apply. The existence of redundant force seriously affects the tracking accuracy of the servo system. Therefore, the main task in designing a position disturbance-type force-applying system is to eliminate its redundant force. In previous studies, a typical method for eliminating redundant force was to use the principle of structural invariance. However, this method does not consider factors such as the nonlinearity and uncertainty of the force servo system. When system parameters change, the effect of eliminating redundant force deteriorates. Alternatively, synchronous compensation can be used, but this requires additional hydraulic components. This paper adopts a model reference adaptive control method, which can effectively eliminate redundant torque while overcoming the influence of nonlinearity and uncertainty of the force servo system on the system, and it only addresses the issue from a software perspective, without the need for additional hardware. [Click for details]