초록 ▼

An improved method and servo control apparatus (C) is provided for controlling the motion of a linear electric motor (A) which in turn generates motion command signals to various apparatus such as a hydraulic steering system (B). Preferably, the servo control apparatus (C) includes a power supply ci

An improved method and servo control apparatus (C) is provided for controlling the motion of a linear electric motor (A) which in turn generates motion command signals to various apparatus such as a hydraulic steering system (B). Preferably, the servo control apparatus (C) includes a power supply circuit (60), a servo amplifier circuit (62), a pulse width modulation circuit (64), an H-bridge drive circuit (66) and an inductive position sense circuit (68). The voltage at a node (42) between coil pairs (38, 40) in the motor (A) is sensed and synchronously demodulated using transmission gates (222, 224) to develop a DC signal representative of armature (30) position from a center location. The signal on a current shunt resistor (200) is synchronously demodulated by transmission gates (208, 209)to generate a signal, the phase of which is determined with respect to the motor drive signal. The phase signal directly indicates whether the armature is off center towards drive coil 38 or drive coil 40.

대표청구항 ▼

[ Having thus described the invention, I now claim:] [1.] A method of developing a position feedback signal in a linear actuator including a pair of coils series connected at a node and disposed on an armature or stator of the linear actuator, each of the pair of coils being magnetically influenced

[ Having thus described the invention, I now claim:] [1.] A method of developing a position feedback signal in a linear actuator including a pair of coils series connected at a node and disposed on an armature or stator of the linear actuator, each of the pair of coils being magnetically influenced by a magnetic field generating member disposed on the other of the armature or stator for causing relative movement between the armature and the stator, the magnetic field generating member being powered by a modulated signal, the method comprising the steps of:generating a first current flow through said pair of coils during a first portion of the modulated signal;generating a second current flow through said pair of coils during a second portion of the modulated signal;sensing a first voltage signal at said node during said first portion of the modulated signal;sensing a second voltage signal at said node during said second portion of the modulated signal; and,combining said first voltage signal with said second voltage signal as said position feedback signal.