Hybrid Pneumatic-Motor Control with Frequency-Fuzzy Command Allocation for Microgravity Simulation

This paper investigates a microgravity environment simulation system based on pneumatic and motor joint control. First, the mathematical models of the pneumatic and linear motor drive systems are established and analyzed to explore their dynamic characteristics. In response to the nonlinear characteristics of the pneumatic system, an appropriate controller is designed to effectively eliminate the impact of nonlinearity. Furthermore, a joint control strategy based on low-pass filtering is proposed, where the low-frequency components of the command are allocated to the pneumatic system and the high-frequency components are assigned to the linear motor system, thus enhancing the system's ability to respond to complex signals. Additionally, to address the issue of slow output convergence under step signals, fuzzy logic rules are introduced for intelligent pre-allocation, which significantly improves the control performance. Finally, the proposed control strategy is validated through both simulations and physical experiments. The results demonstrate that this control strategy not only enables microgravity simulation for large-scale spacecraft but also meets the requirements for complex motion simulations.