Adaptive Control with Process Estimation

Summary A frequent problem encountered during machining with Adaptive Control Constraint (ACC) systems is deterioration of system stability, which is caused by changes in the process parameters such as depth-of-cut or spindle speed. In order to solve the stability problem, the process parameters have to be estimated on-line and immediately used by the ACC control program. In the present paper, a simple computer algorithm is presented for on-line estimation of the process parameters in turning. By applying the proposed method, variations in the process are compensated by subsequent changes in the AC loop gain in order to maintain the stability of the whole system. The method has been demonstrated on a high-power CMC lathe using a small microcomputer as the AC controller in which both the ACC program and the software estimator were stored.