An active axis control system for a conventional CNC machine

A non-invasive approach to implement an active axis controller for a conventional CNC machine is presented. To develop the system a two-stage approach has been taken. In stage one, a generic external axis controller is designed to bring the machine under the real-time control of an external computer. The external controller is interfaced to the CNC machine via the Manual Pulse Generator (MPC) inputs. The external controller uses a special interface to read the machine position. Stage two is the design of the active axis controller. To achieve this, a sensor feedback loop is added to the external controller to enable visual servoing. The developed active axis controller is used to actively track a profile using Visual feedback. The results presented compares the speed of response of the external axis controller with that of the speed of response of the original CNC controller in linear interpolation motion. The accuracy in the performance of the active axis controller is demonstrated by presenting the results of active visual tracking.