Abstract: An optical encoder assembly and a method for measuring a rotation angle in which optical beams are spread over the circumference of a rotating optical disk by means of optical guides (OG). In the preferred embodiment the rotating optical disk has a pair of concentrically arranged circular patterns with alternating transparent and opaque sections. Each beam is input via optical fibers to one of a pair of concentrically disposed OGs with a cylindrical shape (COGs) respectively and propagated through the optical disk to be reflected by a mirror with two concentrically disposed circular patterns of reflective and non reflective sections, reentering the COG through the optical disk in a reverse direction. The COGs then guide the light beams back to an electronic interface that converts the optical signals into electronic signals producing position information.

Abstract: A system and method to eliminate the influence of Dead Time delay in a PWM driven system. The system is implemented using a switching control circuit to operate a pair of upper and lower switching devices in a standard half-bridge arrangement, wherein both a PWM pulse train input and the direction of current flow (current command direction) are both utilized to operate the switching devices. Depending on the direction of the current command, the PWN pulse train input is directly applied to control one of the switching devices (the first switching device), while the second switching device is kept open at least during the closing time of the first switching device. Thus, a precise average PWM output volgate can be obtained, independent of the Dead Time delay, so that a large Dead Time can be used, to provide a precise voltage output over the full range of the DC power supply, while maintaining high reliability.

Abstract: A high-resolution position sensor device for use in precise positioning of servomechanisms, by providing increased resolution using of an encoder mounted on the shaft of a motor, which produces transition pulses through a light-sensitive arrangement using a photodetector. Each time the pulse makes a transition because the groove of the encoder wheel has passed, a reset signal is produced which resets to zero the number of clock pulses which have been measured for that interval between the transition pulses. The transition pulses and the time between them changes with changes in motor speed, while the system clock pulse rate remains fixed. The invention provides a more accurate position sensor, which operates by generating more transition pulses than the encoder itself actually generates. If the encoder produces transition pulses at a given resolution, the sensor device produces output pulses having a higher resolution.

Abstract: An improved method for controlling a servomechanism, applicable to nearly all types of servomechanism control systems. The inventive method improves the performance of servomechanism control systems which utilize a digital feedback sensor by enabling the gain to be varied. The variable gain allowed by the inventive method enables tighter control, and better performance.