Design Of The Solid Rocket Engine Tightening Control System Based On Expert Estimation

Screw connection is the main mode of connection of mechanical products, whose reliability determines the overall performance of the products. As to the soft connection screw parts with a rubber sealing ring, the key to ensure its reliability is to reasonably control the sealing indicator, namely the control of the sealing ring compression rate.However, the research on the control of compression rate are very few in the current field of screw assembly and basically follow the traditional idea of preload control. Due to the nonlinear characteristics of rubber materials, the scatter difference of the compression ratio of the screw sealing ring under the traditional control mode, which seriously affect the quality of products. Based on the screw structure of a thin-walled shell and its control system in an enterprise, we studied the optimization problems in the tightening process and designed a control system of the solid rocket engine tightening machine based on expert estimation.Started with the tightening process of the solid rocket engine, we analyzed the functional requirements of the control system of the screw tightening machine and confirmed the representation parameters of the tightening state of the solid rocket engine and its influence factors. Based on the above analysis, an optimization framework of the control system based on expert predictor control of solid rocket engine screw tightening machine was established. According to the particularity of solid rocket engine tightening mechanism, mechanical characteristics of the screw tightening process was analyzed and based on the relation model between the compression ratio and the key parameters of the screw, a torque angle control model was established for practical engineering application. And then according to the precise control requirements of the amount of compression of rubber sealing ring, we put forward an improved torque-angle control scheme based on the zero-point prediction of the sealing ring, using torque-angle control theory. Since the initial deformation point(zero-point)is difficult to observe and detect directly, we built a dynamic prediction model using the model prediction and expert control technology. Combined with expert reasoning, we forecasted the torque value of the sealing sing on zero-point online and established the control algorithm to predict the zero-point of the sealing ring based on the expert predictor control. Finally, we tested the optimized control system in the hard platform.Compared to the tightening effect of the original control system, the optimized controlsystem has improved the qualified rate of the products, reduced the labor intensity of the operators and improved the production efficiency.