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基于煤岩界面识别的采煤机智能调高控制方法研究

Study on intelligent height adjustment control method of shearer based on coal-rock interface recognition

  • 摘要: 煤岩界面识别及采煤机自动调高作为采煤机智能化的关键技术,是实现采煤工作面的智能化、无人化的重点和难点。实际工作中,多采用人工观测或多种方法结合进行煤岩界面的识别,采煤机通过记忆截割方式和比例-积分-微分(PID)控制等方法进行调高控制,无法适应煤层的复杂变化,且控制算法精度有限。针对采煤机的智能化调高作业问题,设计采煤机自动调高控制系统方案,利用低频脉冲-超宽带(IR-UWB)雷达,采用基于斜投影算子的类最大似然(OPMLL)信号定位方法进行煤岩界面识别,将信号协方差矩阵依次投影到各信号子空间中,得到包含若干单个信号信息的协方差矩阵,进而使用最大似然估计法(ML)进行往返时间延迟估计,并采用迭代方法提高估计精度,获得煤岩界面轨迹;考虑采煤工艺要求、设备限制等具体工况要求,以最大回采率为优化目标,基于有约束优化算法,进行截割轨迹优化;基于采煤机运动学和状态空间模型,采用基于神经网络观测器的间接自适应规定性能控制(NOIAPPC)方法,使用径向基神经网络(RBF NNs)估计系统未知非线性函数,通过二阶滤波器估计反步控制设计中每步的虚拟控制律导数,并使用一种新的神经滑模观测器用于在线估计系统状态变量,只需要已知系统输出,通过调节控制器参数,可使系统瞬态和稳态误差被限制在给定范围内,从而实现采煤机自动调高控制。最后,通过试验验证所提方法的有效性和优越性,为采煤机智能化提供技术支撑。试验结果表明,摇臂转角轨迹跟踪误差百分比约不超过8.2%,截割轨迹最大高度误差约不超过0.01 m。

     

    Abstract: Coal-rock interface identification and automatic height adjustment are critical technologies for achieving intelligent and unmanned mining operations in longwall shearer systems. Traditional methods, such as manual observation or conventional techniques, are often employed for coal-rock interface identification. However, the shearers can't adapt to the complex changes of coal seam by adjusting the height through memory cutting and proportion-integration-differentiation (PID) control, and the accuracy of the control algorithm is limited. To address the challenges of intelligent height adjustment in shearers, this paper proposes an advanced shearer automatic height control scheme. A low-frequency impulse ultra-wideband (IR-UWB) electromagnetic wave radar is utilized, and the oblique projection operator based maximum likelihood like (OPMLL) method is employed for coal-rock interface identification. In this approach, the signal covariance matrix is respectively projected onto individual signal subspaces to generate several covariance matrices containing single-signal information. The maximum likelihood (ML) method is then applied to estimate the round-trip time delay. Moreover, the OPMLL method performs the iteration operation to further enhance estimation accuracy, ultimately yielding a precise trajectory of the coal-rock interface. Considering the specific requirements of coal mining process and equipment constraints, the cutting trajectory is optimized using a constrained optimization algorithm with the maximum recovery rate as the objective. Furthermore, based on the kinematics and state space model of shearer, a neural network observer based indirect adaptive performance control (NOIAPPC) method is developed for automatic height adjustment. Radial Basis Function Neural Networks (RBF NNs) are applied to estimate unknown nonlinear system functions, while the derivatives of the virtual control law at each step of backstepping control are estimated using a second-order filter. Additionally, system state variables are estimated online through a novel neural network sliding mode observer. As a result, by tuning the controller parameters, the proposed method ensures that both transient and steady-state errors remain within predefined bounds. Finally, the effectiveness and superiority of the proposed method are verified through experimental results, providing robust technical support for advancing the intelligence level of shearers. Experimental findings indicate that the angle tracking error of the shearer arm is maintained below 8.2%, the maximum error of the cutting trajectory does not exceed 0.01 m.

     

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