Abstract
In the machine tool industry, direct drive linear motor technology is of increasing interest as a means to achieve high acceleration and to increase reliability. This paper analyzes and compares the characteristics of the tubular linear actuator with the cylindrical Halbach and radial array, respectively. A tubular linear actuator with cylindrical Halbach array, consisting of parallel magnetized arc segments instead of ideal radial and axial magnetized rings, is manufactured. The magnetic field solutions due to the PMs and to the currents are established analytically in terms of vector potential, using the 2-D cylindrical coordinate system. Motor thrust, flux linkage and back emf are then derived. Thrust characteristics according to such design parameters as magnet height and air gap length are also given. The results are validated extensively by comparison with finite element analysis (FEA). Test results such as thrust measurements are also given to confirm the analysis.
