| The 13 th Five-Year Plan for Economic and Social Development of the People’s Republic of China points out that the ability of risk prevention and control must be strengthened by establishing mechanisms of risk identification and early warning in order to actively release risk in a controllable way. With the floor type multi-rope friction mine hoists being popularly applied to coal mines, the collision between adjacent hoisting catenaries induced by large amplitude transverse vibrations, which can damage the rope surface, accelerate the rupture of the rope and accelerate the wear of the head sheave, sometimes occurs. It has become one of the risk factors that seriously threaten the safety of mine hoisting. To solve this engineering failure, the present paper has conducted deep researchs from the following four aspects:(1) A multi-source coupled vibration model of hoisting catenaries has been established. Firstly, the transverse-longitudinal coupled vibration equation for a vertical translating hoisting main rope subjected to external excitation induced by axial fluctuations of the head sheave has been derived. The dynamic tension at the sheave end of the main rope has been analyzed by numerical simulation in order to provide a theoretical baisis of dynamic tension for the modelling of transverse vibrations of catenaries. Subsequently, a multi-source coupled vibration model of hoisting catenaries has been established by considering axial fluctuations of head sheaves and friction pulley, hoisting velocity, diameter of rope groove, length of catenary, rope tension and other coupled factors. A mathematical expression for the transverse vibration displacement was then derived. Lastly, the validity of the established model was confirmed based on the truly measured data.(2) The multi-source coupled vibration characteristics of hoisting catenaries have been investigated and reduction of large amplitude transverse vibration has also been conducted. Firstly, adopting the axial fluctuating displacements of the head sheave and the friction pulley as the external excitations and considering the higher order of the axial fluctuations of the head sheave and friction pulley, the multi-source coupled vibration characteristics of hoisting catenaries were discussed based on the ordinary differential equations of the transverse vibrations for hoisting catenaries. The research results show that the hoisting acceleration and the diameter of rope groove are the weak coupled parameters for the large amplitude transverse vibrations of hoisting catenaries, the axial fluctuating order of head sheaves, the hoisting velocity, the hoisting load and the length of catenary are the strong coupled parameters for the large amplitude transverse vibrations of hoisting catenaries. Subsequently, the safety range and reduction criterion for the transverse amplitude of hoisting catenaries have been investigated. From the perspective of reducting the large amplitude transverse vibrations of hoisting catenaries, the reasonable values of the strong coupled hoisting parameters such as the constant hoisting velocity, the hoisting load and the length of catenary have been determined.(3) A method to measure transverse displacements of moving catenaries using vison tracking has been developed. Firstly, to solve the difficulty in selecting a feature reference point in measuring transverse vibrations of moving catenaries, applying machine vision techniques, a solution transforming the measurement of transverse vibrations of line-shape targets into that of moving points was proposed. Subsequently, a method using Kalman prediction and Mean Shift tracking was developed to measure the transverse displacements of the measured point. Lastly, the applicability and accuracy of the proposed method were validated based on the theoretical model and a simulation experiment rig.(4) The fault diagnosis and prevention of collision behavior of hoisting catenaries have been carried out. Firstly, the software and hardware systems measuring the source information were constructed. Subsequently, the fault diagnosis of catenary collision was conducted using the truly measured data and the theoretical model. The research results show that the failure of tension equilibrator and the axial fluctuations of head sheaves are the dangerous sources that excite catenary collision. Lastly, the applicability of the safety assessment criteria for the axial fluctuating displacements of head sheaves have been dicussed. The online inspection and pre-warning system for the axial fluctuations of head sheaves and the postures of tension equilibrator were developed to prevent the catenary collision.The research achievements of the present paper will provide technical supports for the safety design, operation monitoring and engineering maintenance of floor type multi-rope friction mine hoists. They can also provide a good reference for the fault maintenance and prevention of Blair type multi-rope winding mine hoists. |
