Abstract: The present invention relates to an apparatus and method for generating digital electrical signals which are representative of the angular position and rotational velocity of a rotatable shaft or similar movable mechanical component in a servomechanism. In particular, the present invention utilizes oversampling techniques to create an accurate, flexible and responsive method for determining shaft position on a high speed motor. The present invention also includes methods for overcoming deadtime losses and velocity lag.

Abstract: A modular current sensing system for a servo control system that includes a magnetic core with an open center portion and a connection plate that includes at least three wire connectors, wherein the wire connectors are capable of connecting at least two wires electrically in series. The system also includes a plurality of wires, including a first wire with a first end and a second end, wherein the first end of the first wire is electrically connected to a first power source, and the second end of the first wire is connected to the connection plate at the first wire connector and wherein the first wire passes through the open portion defined by the magnetic core at least once. A first motor current flowing through the first wire induces a core current to flow in the magnetic core, causing the magnetic core to emit a magnetic field. A Hall effect sensor detects the magnetic field, produces an output current, and delivers the output current to a control device within a servo control system.

Abstract: An apparatus and method for generating digital electrical signals which are representative of the angular position and rotational velocity of a rotatable shaft component in a servomechanism includes a resolver which is connected to the rotatable component. The resolver generates analog electrical output signals which are representative of an excitation signal modulated by both the sine and cosine of the electrical angular or position of the motor. The output signals from the resolver are fed to a digital signal processing circuit which employs software algorithm techniques to define a plurality of tasks which are implemented sequentially to obtain the desired angular position and velocity signals. First, the sine and cosine signals are read from the resolver through respective analog-to-digital converters. The sine and cosine signals are demodulated by multiplication with the excitation signal, and the undesired higher frequency components are deleted by filtering.

Abstract: An apparatus and method for generating digital electrical signals which are representative of the angular position and rotational velocity of a rotatable shaft in a servomechanism includes a resolver which is connected to the rotatable component. The resolver generates analog electrical output signals which are representative of an excitation signal modulated by both the sine and cosine of the electrical angular position of the motor. The output signals from the resolver are fed to a digital signal processing circuit which employs software algorithm techniques to define a plurality of tasks which are implemented sequentially to obtain the desired angular position and velocity signals. First, the sine and cosine signals are read from the resolver through respective analog-to-digital converters. The sine and cosine signals are demodulated by multiplication with the excitation signal, and the undesired higher frequency components are deleted by filtering.

Abstract: A pulse width modulation (PWM) control circuit provides for improved implementation of position, velocity and current feedback loops for digital servo control of a multi axis robot. The PWM circuit utilizes a single resistor for sensing joint motor drive current. Circuitry is also disclosed for reducing audible noise and motor heating in large servo motors used for joint arms operated at relatively low PWM frequencies by reducing the motor ripple current.