Electronic cam control system
AssigneeGE Fanuc Automation North America, Inc.
InventorsAndrzej Aderek, Michael Joseph Tuso, Anirban De
Life of this patent
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Abstract
An electronic cam servo apparatus uses a digital servo controller to perform motion equivalent to a mechanical cam. The control apparatus has one data table representing a characteristic of a mechanical cam and utilizes a data interpolation and the first derivative of a cam position profile to determine position and velocity commands to drive a servo motor which performs motion equivalent to a mechanical cam. Alternatively, the control apparatus uses the first cam specific data table to determine the position, velocity and torque/current command to drive a servo motor. The apparatus may additionally use a second data table representing varying cam load to obtain a more accurate torque/current command correction.
Claims28
A method for controlling cam servo motion in an electronic cam servo control system, the electronic cam servo control system including a processor, a memory loaded with a cam position profile table, a digital servo controller to perform motion equivalent to a mechanical cam, an encoder, and a control program, said method comprising the steps of:
- importing cam shaft position and cam shaft velocity from an encoder interface;
- calculating a cam position command;
- calculating a first derivative of the cam position profile;
- calculating a cam servo velocity compensation command by multiplying the first derivative of the cam position profile by the cam shaft velocity;
- and
- sending a cam position command and a cam shaft velocity compensation command to the digital servo controller.
An electronic cam servo control system comprising:
- an encoder;
- a processor configured to:
- import a cam shaft position and cam shaft velocity acquired from said encoder;
- calculate a cam position command;
- calculate a first derivative of the cam position profile;
- calculate a cam servo velocity compensation command by multiplying the first derivative of the cam position profile by the cam shaft velocity;
- and
- send a cam position command and a cam velocity compensation command to a digital servo controller;
- a memory to store cam position profile, cam shaft position and cam shaft velocity acquired by said processor and calculation results of said processor;
- and
- a digital servo control module to receive and perform cam position and velocity commands generated by said processor.
Dependencies are inferred from the claim text.