كنترل ارتعاشات لرزه ابزار داخل تراش با بهره گيري از يك الگوريتم كنترل تطبيقي جديد با پس خور مستقيم سرعت

Boring bar chatter control using a novel adaptive direct velocity feedback controller

در اين مقاله، براي حذف لرزه ابزار در فرآيند تراشكاري داخلي از يك سيستم كنترل تطبيقي جديد با پس خور مستقيم سرعت استفاده شده است. در الگوريتم كنترل پيشنهادي، ضريب بهره براساس شرايط كاري عملگر و وضعيت ارتعاشي ابزار تنظيم مي شود. تا توان مصرفي عملگر همواره متناسب با شدت ارتعاشات فرآيند براده برداري باشد. با اجراي آزمون هاي كنترل ضربه، مقادير بهينه براي پارامترهاي كنترل كننده تعيين شده اند. همچنين، كارايي سيستم كنترل تطبيقي در فرآيند تراشكاري داخلي آلومينيوم آلياژي 6063-T6 تاييد شده است. سيستم كنترل ارايه شده مي تواند سفتي ديناميكي ابزار و عمق برش متناظر با آستانه پايداري را بيش از 10 برابر افزايش دهد.

In this paper, a new adaptive control system is presented for suppression of boring bar chatter in internal turning process. The vibration control system is consisted of electromagnetic actuator, boring bar, accelerometer and a novel adaptive control algorithm. The controller gain is adaptively adjusted according to the operating condition of actuator and the level of boring bar vibrations. Such that the consumed actuator power always remain proportional to the intensity of chatter vibrations due to cutting process. As a result, the gain adaptation algorithm is indirectly developed by using the dynamic characteristics of actuator-boring bar assembly. Firstly, the tunable parameters of adaptive controller are optimally identified by conducting impact tests. Secondly, the performance of adaptive controller is investigated during the internal turning of Aluminum alloy 6063-T6. The presented adaptive control system can improve the dynamic stiffness of boring bar as well as the critical limiting depth of cut on stability chart by at least 10 folds. Due to optimal performance of the adaptive controller, the dominant magnitude of boring bar’s power spectral density is successfully attenuated up to 78 dBs. Also, the roughness of cut surface is reduced from above 40 micrometers in control-off cutting test to below 5 micrometers in control-on test. Moreover, the actuator cost is considerably reduced for adaptive controller, in comparison to the optimal constant-gain integral controller. As a result, by using the proposed adaptive control algorithm, a smaller electromagnetic actuator with lower power capacity can be used for chatter suppression at the same cutting conditions.