Magnetic field optimization and output characteristic analysis of macro–micro precision actuator based on grey wolf optimizer

To enhance the output thrust of a macro–micro precision actuator while maintaining its precision positioning capability, an optimization design method for the macro-motion structure based on Halbach permanent magnet arrays is proposed. By establishing an equivalent magnetic network model of the macro-motion magnetic circuit, the analytical efficiency for the magnetic field distribution is improved. A single-factor analysis method is employed to reveal the influence of key parameters, including axial permanent magnet length, air-gap thickness, and winding thickness, on the maximum output thrust. The Grey Wolf Optimizer is applied to perform comprehensive optimization of the main parameters, yielding a structural dimension combination that maximizes thrust. On the basis of the optimization results, a prototype is fabricated and experimentally tested, and the results show that under a 6A drive current, the macro-motion stage achieves an output thrust of 190.2N, with a relative error of 2.4% compared with the optimized model prediction. Meanwhile, a stroke positioning of 35.32mm is achieved within 25ms, with a maximum nonlinear error of 0.469mm, demonstrating good linearity of displacement output. This method ensures high-thrust output while maintaining rapid precision positioning, providing an effective technical solution for high-load precision drive applications.