Dynamic Characteristics Analysis And Vibration Suppression Of Ground Mounted Friction Mine Hoist

Ground mounted friction mine hoists are widely used in mining enterprises.With the increase of mining depth of mineral resources,the hoists wire-rope are also becoming longer.With the increase of wire-rope length,the flexibility of wire-rope is prominent,and the vibration is more obvious during the operation,especially in the process of brake parking and emergency braking.Frequent vibration of wire-rope will aggravate wear and tear,resulting in the occurrence of breakage and serious accidents.Therefore,in order to reduce the vibration of the hoisting system,improve the life of the wire-rope and the efficiency of the equipment,it is necessary to study the vibration characteristics of the ground mounted friction mine hoists,and propose a kind of vibration suppression program of wire-rope.Based on certain assumptions,the longitudinal distributed parameter model of the ground mounted friction mine hoist without excitation was established according to Hamilton’s principle.And the distributed parameter model was discretized by the Galerkin weighted method,and the simulation result of the model was obtained by MATLAB.The validity of the model was verified by experiments data.The time domain,frequency domain and time-frequency domain of the test vibration signals under normal operation and constant deceleration conditions of the hoisting system are analyzed by signal processing and analysis methods such as wavelet threshold denoising and wavelet transform.And the causes of vibration are analyzed from the perspective of theory and experiment.According to the vibration characteristics of the hoisting system,wire-rope vibration suppression program is proposed.The vibration energy of the system is quickly dissipated and stabilized by the external controller.According to the Lyapunov second stability principle,the Lyapunov state controller for suppressing the longitudinal vibration of wire-rope is designed on the basis of the distributed parameter model.The hydraulic cylinder drives the tension wheel as the actuator to reduce the vibration generated by the hoisting system during operation.Research indicates that:(1)The established longitudinal distributed parameter model of the ground mounted friction mine hoist without excitation can effectively reflect the key characteristics of the hoisting system dynamics,and can be used as the model basis for controller design.(2)During the operation,the ground mounted friction mine hoist will generate vibrations in three directions:longitudinal,transverse and lateral,among which the longitudinal vibration is the main characteristic,especially in the braking stage,there is a vibration acceleration of exceeding 2m/s~2 in the longitudinal vibration.The vibration frequency generated by the operation of the hoisting system is mainly low frequency,concentrated in 1～10Hz,and the frequency generated by the bottom of well brake is lower than that generated by the wellhead brake.The power frequency and frequency multiplication generated by the rotation of the pulley make the mine hoist generates corresponding frequency vibration during normal operation.Constant deceleration braking will generate stronger vibration acceleration than normal braking.(3)The new state controller greatly reduces the longitudinal vibration of the wire-rope at the hoisting container,the vibration acceleration peak is only 0.2 m/s~2.The vibration frequency is reduced,the convergence speed is accelerated,and the control effect is good.The vibration shock of 2.3 m/s~2 still appears in the parking phase of PD controller,which is basically the same as that of the hoisting system without controller.The convergence time reaches 2.5 s,and the control effect is poor.