Stability and stick-slip vibration analysis and control of coke pushing system based on linear and nonlinear state feedback

Purpose For the purpose of studying the stability and stick-slip vibration characteristics of the coke pushing system, a dynamic model used to describe the friction self-excited vibration system is established in the article. Design/methodology/approach The Stribeck friction model is introduced into the established dynamic model and the theoretical calculation and numerical simulation are carried out. The critical instability speed of the coke pushing system is 0.45 by theoretical calculation, and the numerical simulation results verify the correctness of the theoretical calculation. In order to control the stability and stick-slip vibration of the coke pushing system, a linear and nonlinear state feedback controller is designed in this paper. Findings Stick-slip vibration emerges in the coke pushing system when its operating speed is below the critical instability speed of 0.45, while the system stabilizes at speeds above this threshold. The linear gain of the state feedback controller can reduce the critical instability speed of the coke pushing device to achieve stable operation at lower operating speeds. Meanwhile, its nonlinear gain can reduce the limit cycle size, suppress stick-slip vibration amplitude and significantly improve the vibration state of the whole system. Originality/value (1) A dynamic model used to describe the friction self-excited vibration of the coke pushing system is established. (2) Design a linear and nonlinear state controller to control the stability and stick-slip vibration of the coke pushing system. (3) Investigate the effect of linear and nonlinear state controllers’ linear gain on the critical instability speed and nonlinear gain on the vibration limit cycle size of the coke pushing system.