Patent ID: 6803737
Filing Date: 2004-10-12
Classification: G05B,Y02P

Abstract:
Control system for a d.c. motor (10) of the type comprising a rotor and a stator, a coil assembly having a plurality of coils and a magnetic circuit, one integral with the rotor and the other with the stator, the rotor being driven in rotation by an electric current passing through the coils, and powered by a control system (14) comprising:a position detector (30, 32) co-operating with the rotor; a power supply circuit (34) to apply to the terminals of the coils a supply voltage to generate the electric current, and a control circuit (36), with a view to enabling a moving part (24), actuated by said motor (10) and the movement of which is measured by said detector (30, 32), to reach a target position Pc defined by a number of steps dc to be executed; characterized in that, during a positioning phase, the control circuit (36), performs the following operations determining the number of steps (d) to be executed to reach the target position Pc; determining the number of steps executed (c) by applying a pulse (la) delivering a known enemy (Eao); determining the drive energy (Ep) and braking energy (Ef) to be supplied by a positioning pulse (Ip) and a braking pulse (If) respectively to reach said target position Pc; and controlling the power supply circuit (34) for applying the determined positioning pulses (Ip) and braking pulses (If) to said motor (10) short-circuits said coils until stoppage is observed by said detector (30, 32), comparing the stoppage position with the target position Pc and, if the target position Pc has not been reached, starting a new cycle by applying a voltage across the terminals of said coils via the power supply circuit (34).