Control circuitry for producing signals to control motors which propel a ile platform for a standing paraplegic. Logic circuits connect a 3-axis joy stick controller to four permanent magnet DC motors mounted on the platform such that the platform follows in the direction of the displacement of the...http://www.google.fr/patents/US4284929?utm_source=gb-gplus-shareBrevet US4284929 - Ambulator control circuitry
