Abstract: AC servo motor drives which allow several AC drives to be connected in parallel and allow for the connection and reconnection of AC servo motors to be accomplished primarily through a central processing unit (CPU). Thus, multiple AC servo motor drives may be ganged under the supervision of the CPU to provide a servo motor with multiple times the current available from a single drive and optionally redundancy in the drives. To provide necessary coordination, the required motor current magnitude and phase (current vector) are broadcast by an axis controller to the drives. This command current vector is broadcast over a high speed serial data bus which allows many simultaneous listeners (the AC servo motor drives). To protect against damage to each drive, each of the three current output terminals is preceded by an output filter. The output filters preceding the terminals permit phase by phase parallel connection of several drives in the service of one servo motor.

Abstract: A labeling machine servo motor to drive the label feed is combined with a control system which tracks the surface of the item to be labeled wherein all of the parameters affecting the placement of the label are instantly programmable. Label motion starting position, label acceleration and deceleration rates, label speed, and label stop position are all under program control and may be adjusted within the control system or by an external device utilizing a network, a serial interface, or a discrete input/output interface to the control system. In the preferred embodiment, the control system comprises a servo controller easily programmable and reprogrammable in the necessary parameters to effect more accurate and faster label application.

Abstract: A brushless AC servo motor control and modified motor to minimize the rotational acceleration and deceleration of a semiconductor wafer during processing steps where fluid is applied in a thin coating on the wafer. The control utilizes sine and cosine encoder outputs of single cycle and multiple cycle per revolution to calculate motor shaft position by an inverse tangent calculation of sine and cosine ratios. Resolution of motor shaft position is greatly improved as is rotational velocity control. In response to a prediction of desired shaft position in comparison with actual position the three field currents are adjusted to change the torque applied to the rotor and shaft. In the semiconductor wafer manufacturing application the motor shaft is modified to permit vacuum attachment of the wafer to the disc that rotates with the shaft.