A compact direct-drive linear synchronous motor with muscle-like performance

We present the design of a novel direct-drive linear permanent magnet synchronous motor with a high continuous-duty force-to-mass ratio. We use an analytical electromagnetic model to find optimal dimensions for a new magnet configuration, comprising nested tubular Halbach arrays. We further use the analytical model to map out the design space for these motors, and investigate possible designs for motors with muscle-like force production. We then describe the design of a 100 g-scale motor based on the optimization, with water cooling and a lightweight structure. Experimental results suggest that this motor is capable of over 140 N/kg continuous force production, and demonstrate that it can be used for positioning at over 1 m/s and with 40 g acceleration unloaded.