Aerospace Technic and Technology

The production of complicated profile parts for aerospace technology is carried out by processing along spatial paths. The nature of the movement of each axis of the equipment is dynamic and unsteady-state. Accuracy must be ensured not only in a steady-state but also in dynamic mode. The determination of dynamic characteristics of the executive bodies is an important and urgent task to optimize the control process. An experimental research method using capabilities of the CNC system, which was equipped with additional hardware and software, is proposed. This allows to register a large number of parameters that describe the state of the equipment, the solving of the task of trajectory interpolating, the formation of control actions, the actual movement of the executive bodies. The methods of conducting experimental studies with the setting of a stepwise change in speed and with a change in speed according to the harmonic law for an open-loop and closed-loop system using various components of the feedforward in the regulator are considered. The use of circular interpolation for the formation of a harmonic law of speed change is proposed. The results of the study of the dynamic of the transition process of an open system are shown. The frequency characteristics of the drive under study are obtained. Its bandwidth is determined. The study of the moving process when the axis velocity changes in harmonic law was performed within the passband. The possibility of determining the maximum permissible values of inertial loads by the nature of the change in actual acceleration is shown. The influence of the regulator feedforward composition on the accuracy of positioning of the servo drive and the accuracy of the contour processing at various frequencies of the control action is studied. For each feedforward method, the frequency ranges of the control action are determined, on which the specified processing accuracy is ensured. It was found that the technological frequency limitation by the accuracy of the reproduction of the path turned out to be significantly more stringent compared to the classical approach for determining the bandwidth.

complicated profile parts; CNC; dynamic response; speed; acceleration; jerk; position controller; accuracy; positioning error

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