The existing research on coal gangue identification based on vibration usually assumes that coal gangue particles are ideal shapes. To understand the vibration response difference in hydraulic support caused by coal and gangue with real shapes, this paper uses a three-dimensional (3D) scanning technology to determine the real shape of coal particles. The process of coal and gangue impacting the tail beam at different angles was simulated in the LS-DYNA software package, and the effects of shape parameters, velocity, and coal strength on the difference in vibration signals caused by the two were analyzed statistically. The conclusions are as follows: the vibrational response of the tail beam is concentrated mainly in the area between the ribs. The regularity of the velocity signal caused by gangue is better than the regularity of the velocity signal caused by coal, and the attenuation speed of the acceleration signal of gangue is slower than the attenuation speed of the acceleration signal of coal. The probability distributions of the velocity and acceleration responses were analyzed statistically, and the results show that the results from coal can be well fitted by a logarithmic normal function, and the standard deviations of velocity and acceleration are 0.05591 and 489.8, respectively. The gangue results are fitted by the gamma function and the Weibull function, and the standard deviations are 0.13531 and 737.9, respectively, showing that the fitting function has the potential to be used as the basis for coal gangue identification. The change in coal strength has little effect on the vibration response of the tail beam. With increasingly falling velocity, the vibration signal intensity of the tail beam increases, but the discrimination between coal and gangue weakens; therefore, measures should be taken to reduce the falling velocity of the rock mass. The research results of this paper can provide a reference for further study of coal gangue identification methods based on vibration.

Chock-shield support is usually used in undergroud coal mining to protect the roof. However, as the mining depth gets deeper, impact load that came from the roof becomes stronger and more frequent. This causes the support to bear a large number of dynamic loads, and reducing its reliability. To improve the support performance of the chock-shield support, the mixed-kinetic model was established using the mechanical-hydraulic co-simulation method. The load distribution law of the support joint under impact load form different stability forces, impact load amplitude, and impact frequency is discussed. The mechanical-hydraulic cooperative response of the chock-shield support are obtained. The results show that different joints show typical non-uniformity characteristic during the loading process. The proposed mechanical-hydraulic co-simulation method can more accurately obtain the dangerous points of hydraulic support reliability. The results of this study will help to improve the reliability of the chock-shield support.

To study the load transfer characteristics of a two‐legged shield powered support, a numerical simulation model of the support was established using the multibody dynamics software ADAMS. The model took full account of the hydraulic‐elastic deformation characteristics of the support, as a series spring‐damper system was used to replace the leg and the equilibrium jack. The canopy, goaf shield, lemniscate bars, and equilibrium jack are equivalent to flexible bodies. The setting force of the leg was provided by the preload of the equivalent spring, the static roof load was simulated using a slope signal, and the impact load was simulated using a step signal. Using the model, the impact and excitation effects of each hinge joint of the support were analyzed under different impact load conditions across the canopy. The results show that the location of the impact load affects the force transmissions of all hinge points of the support. Both the impact effect and the excitation effect are at a minimum when the impact force is located near the leg action line. These results are useful for the adaptive control and structural design optimization of the support.

This paper addresses the challenge of measuring and controlling the initial support force of hydraulic supports, which can be complicated by pressure fluctuations and losses in the hydraulic supply system. To this end, an online tracking error measurement method is presented based on optimal control, which involves developing a fluid supply system model and integrating the tracking error with the reference trajectory to streamline controller design. Our approach uniquely combines adaptive dynamic programming (ADP) based optimal control with a prescribed performance function (PPF), effectively constraining tracking error and adapting to system uncertainties in real-time. A novel online adaptive learning law is proposed to estimate the unknown critic neural network (NN) weights, thereby eliminating the need for an actor NN and enhancing control performance. Simulation results demonstrate the developed approach achieves superior accuracy and faster response times compared to existing methods.

The automatic height adjustment of a shearer cutting drum is a key technology for shearer automation. However, a fundamental and important requirement for underground electronic products is explosion-proof rating, which creates great challenges to the research on the control method of the shearer height adjustment system. To address this problem, a novel shearer height adjustment control method was proposed based on basic fuzzy control, and the feasibility of the height adjustment method was studied with the help of multisoftware cosimulation technology. First, the drum cutting coal model was established using Finite Element Method (FEM) software LS-DYNA, the mechanical model of the gear transmission system model and the height adjustment system were constructed with the multibody dynamics software ADAMS, the hydraulic height adjusting system model was constructed with AMESim, and a fuzzy controller for shearer height adjustment was developed in Simulink. Then, the data conversion interface between the mentioned models was constructed using MATLAB, to obtain the cosimulation model for the shearer automatic height adjustment. Finally, with the help of fuzzy control method, the feasibility of the cosimulation model used in the adaptive control method of the shearer drum height adjustment was verified. The results show that the cosimulation model can adequately describe the height adjustment process of a shearer, which lays a foundation for the optimization of adaptive height adjustment method. At the same time, the proposed model is also applicable for studying the dynamic characteristics of the mechanical-electrical-hydraulic coordination in the process of shearer adaptive height adjustment.

Conical pick is a diffusely applied cutting tool in rock excavation in the coal-mining industry. In order to enhance the capability of conical pick, a new rock cutting method based on increased free surface is proposed. To research the peak cutting force and fracture morphology, ANSYS/LS-DYNA is used to establish the conical pick and rock interaction model. To obtain the fracture morphology of rock plate, eroding contact, erosion element failure, and damage constitutive are considered in the numerical model. Mechanical properties test and rock plate cutting experiment are carried out to guarantee and verify the correctness of the numerical model. The width and height of rock plate influencing peak cutting force and fracture morphology are studied, and the stable peak cutting force is defined. Lower width and height contribute to more fragments in smaller dimension produced during the rock plate cutting process. Besides, higher skew angle leads to more fragments. The peak cutting force decreases with the increasing width and height of rock plate while reaching stable peak cutting force, and it reduces and then remains stable with the increasing cutting position and symmetrical with skew angle of zero degree.