<p>This paper addresses the issues of unknown wind disturbances and grinding force control accuracy faced by offshore wind turbine blade repair robots during high-altitude operations. To deal with these challenges, a pneumatic system constant force control device is designed, and a controller based on the improved active disturbance rejection impedance control (ADRIC) algorithm is put forward to govern this device. This algorithm combines dead-zone compensation and gravity compensation technologies to effectively solve the problems caused by the dead-zone characteristics of the electrical proportional valve and the changes in tilt angles during the grinding process. As a result, it significantly improves the system's anti-disturbance ability and force control accuracy. By establishing the mathematical model of the passive compliance device and designing four force control simulation scenarios, namely constant value, sine wave, triangular wave, and trapezoidal wave, the dynamic response performance and stability of the algorithm were verified. The experimental results show that compared with the traditional active disturbance rejection control (ADRC) algorithm, the improved algorithm demonstrates substantial superiority in force tracking accuracy, adjustment time, and anti-disturbance capabilities. Specifically, the adjustment time is shortened by approximately 50–66.7%, and the maximum error is reduced by about 26.27–67.1%. This provides a reliable approach for achieving high-precision force control of offshore wind turbine blade repair robots in complex environments, ensuring more efficient and accurate blade repair operations.</p>