Frederick R Stewart

US Patent:

7421308, Sep 2, 2008

Filed:

Jan 26, 2007

Appl. No.:

11/627631

Inventors:

Michael B. Nussbaum - Newton MA, US
Michael R. Shannon - Medford MA, US
Frederick A. Stewart - Watertown MA, US

Assignee:

GSI Group Corporation - Billerica MA

International Classification:

G05B 19/29

US Classification:

700186, 700 56, 250236, 318600, 3461074

Abstract:

A limited rotation motor optical scanning system is disclosed that includes a limited rotation motor scanner, a digital controller servo system, a position feedback unit, a wide angle compensation unit, a digital processor, and an adjustment unit. The limited rotation motor scanner element is adapted for directing an energy beam to at least one location within a field of view. The digital controlled servo system is adapted for controlling motion of the limited rotation motor scanner element in accordance with a servo command waveform. The position feedback unit is for providing a position feedback signal indicative of a rotational position of the limited rotation motor scanner element. The wide angle compensation unit is for receiving the position feedback signal and for providing a boost signal that is representative of a boost factor that compensates for torque constant variation with the rotational position of said limited rotation motor scanner element. The digital processor is for providing a set of control parameters for use during the command waveform in conformance with which the command waveform will be employed to control motion of the limited rotation motor scanner element. The adjustment unit is for providing an adjusted output signal responsive to the control parameters and responsive to the boost signal to control the motion of the limited rotation motor scanner element while compensating for torque constant variation with the rotational position of the limited rotation motor scanner element during the command waveform.