US Patent 7135827 Sawyer motor forcer with integrated drive electronics

A digitally controlled, integrated Sawyer motor forcer consists of a rigid mechanical housing containing one or more linear motor segments, integrated control electronics, cooling means, and optional feedback sensors. The integrated control electronics include digital processing circuits, an external host communication interface, power conditioning and supply circuits, forcer phase amplifiers, input/output circuits and optional feedback sensor circuits. The integrated controller also provides control, amplifier, input/output, and sensor circuits for additional external motor axes that may be attached to the forcer as needed for specialized machines. The forcer may be operated in an open-loop mode without feedback sensors, or in a closed-loop servo mode using integrated feedback sensors of various types. Cooling means are included in the forcer to reduce the temperature rise caused by power dissipation in the forcer coils and the integrated electronic elements. The invention greatly improves the safety of both linear and planar Sawyer motor systems by enabling the use of low voltage forcer coils, and by reducing electromagnetic interference. Forcer control performance is increased while system cost and complexity is reduced. The forcer is designed to work with standard Sawyer motor platens.