| As the key equipment for mechanized mining in fully mechanized mining face,hydraulic support is mainly responsible for roof support and autonomous follow-up.Among them,the position control of pulling and pushing during the autonomous follow-up process is directly related to the smooth running of the coal mining face.It is very difficult to control the hydraulic support because the load of the hydraulic support is very complicated and there is a coupling relationship between the adjacent cylinders.the current working face position straightness cannot meet the requirements of unmanned or less humanized mining in the underground.At present,the straightness of the working face position can not meet the requirements of unmanned or less manned underground mining in China.However,the research on the multi-cylinder collaborative system of hydraulic support group is not mature at home and abroad.Therefore,funded by the National Natural Science Foundation of China Joint Fund Project "Study on high pressure,large flow and high water-based digital valve and its control method in mining",this article is to take the hydraulic support group multi-cylinder cooperative control system as the research object,comprehensively using the system's nonlinear dynamic theory,hydraulic transmission theory and nonlinear control theory,etc.,take in-depth research on the position control strategy of the multi-cylinder cooperative system.These researches provide important theoretical support and technical means for the straightness control of the hydraulic support group multi-travel cylinder cooperative control system.The main work research contents and results of the thesis are as follows:(1)The working principle of the multi-cylinder cooperative system of hydraulic support group is introduced in this paper,which includes the different working conditions of the multi-cylinder cooperative system in the process of pulling and pushing and the state-space model of the multi-cylinder cooperative system is established;A physical model is built in AMESim software based on the electro-hydraulic control system of the ZY3200/08/18 D type shielded hydraulic support;The source program of the designed multi-cylinder cooperative system position control method is compiled in MATLAB/Simulink software;Co-simulation has laid the foundation for the preliminary theoretical verification of the position control method of the subsequent multi-cylinder cooperative system.(2)According to the pulling frame process of the multi-cylinder cooperative system,the specific working conditions of sequential pulling frame,staggered pulling frame and group pulling frame are analyzed;A nonlinear disturbance observer is designed to estimate the integrated force disturbance;for the sequential pulling method,a position error constrained robust backstepping control method is proposed;Aiming at the staggered frame and group frame methods,based on the equivalent control strategy,a position/velocity constraints robust backstepping control method is proposed.Combining the dynamic surface theory to simplify the design process of the controller,and using the Barrier Lyapunov theory to prove the stability of the controller;The simulation results show that the nonlinear disturbance observer can accurately estimate and compensate the integrated force disturbance,and the output state constrained method effectively improves the position accuracy and synchronization accuracy of the multi-cylinder synchronous frame.(3)Aiming at the pushing process of the multi-cylinder cooperative system,the coupling relationship between adjacent shifting cylinders is analyzed,a threshold function is defined,and the time-sharing pushing model of the multi-cylinder cooperative system is established;A coupled disturbance observer is designed to estimate the integrated disturbance force of the coupled multi-cylinder system,the various coupling gains of the Hurwitz matrix are designed,and the stability of the observer is proved;A sequential robust backstepping controller for the multi-cylinder cooperative pushing system is proposed;A weight allocation method is designed to track the desired trajectory and the trajectory of the previous cylinder,and the control performance of the multi-cylinder cooperative system is comprehensively evaluated by combining the displacement difference and speed difference between adjacent cylinders;The simulation results show that the coupled disturbance observer can accurately estimate the integrated disturbance force of the multi-cylinder coupled sequential motion system.The designed sequential robust backstepping controller not only improves the accuracy of multi-cylinder position control,but also reduces the generation of coupling forces.(4)Aiming at the situation that only the position output signal of the multi-cylinder cooperative system can be measured,the Brunovsky model of the multi-cylinder cooperative system is established;A high-order sliding mode state observer is designed to estimate the state of other systems using position signals;A radial basis neural network disturbance observer is designed to estimate the integrated disturbance force of the multi-cylinder synchronous pulling system;A radial basis function neural network approximator is designed to estimate the nonlinear function of the multi-cylinder sequential pushing system;Combining the state observer and the disturbance observer,the output position control strategy of the multi-cylinder cooperative system is proposed and its stability is verified;The simulation results show that the high-order sliding mode state observer can accurately estimate the state of the system,and the neural network approximator can accurately estimate the nonlinear function of the system.And the coupling relationship between the two observer is solved,and the control precision of the output control is improved.(5)In order to further verify the effectiveness of the designed multi-cylinder collaborative system control strategy,a three-cylinder collaborative control test bed based on xPC/Target rapid prototyping technology is built.And a three-cylinder loading system is designed to simulate the different loading forces received by adjacent pushing cylinders.The experimental results show: the tracking error of the designed position/velocity constraints synchronous control strategy is only 1 mm,and the synchronization error is 0.8 mm;the maximum tracking error of the designed time-sharing pushing control strategy based on weight distribution is about 2 mm,and the termination errors are 1 mm,1.8 mm,and 2 mm,respectively;the designed synchronization accuracy of the pulling frame of the output controller is basically stable at about 1 mm,and the end error of pushing frame of the output controller is about 0.5 mm.Compared with common comparison controllers,multi-cylinder cooperative control strategies are proposed in this paper,which has higher position accuracy in the pulling process,pushing process and output control.It is beneficial to improve the straightness of the working face,and provides theoretical and technical support for realizing unmanned or less humanized intelligent mining in underground mines.The dissertation has 92 figures,4 tables and 166 references. |
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