Design optimization of an arc-edged trapezoidal Halbach array in the linear permanent magnet actuator for precision engineering

In this paper, an arc-edged trapezoidal Halbach PM linear actuator for precision engineering is proposed. In this linear actuator, the Halbach PM array is utilized as a mover. To take into account the magnetic field distortion caused by the finite-length of the PM array near the boundaries, a long-period Fourier series expansion is applied to calculate the field distribution of the PM array and the associated thrust. They are then validated by the finite element method and physical experiments. Finally, by a fitting-based local searching method, design optimization is implemented to achieve a small thrust ripple as well as a large mean thrust.