Automatic profiling control using a boom-type roadheader requires an understanding of horizontal and vertical swing angles of the cutting boom. In this study the vertical angle of the cutting boom is discussed. First,...Automatic profiling control using a boom-type roadheader requires an understanding of horizontal and vertical swing angles of the cutting boom. In this study the vertical angle of the cutting boom is discussed. First, a vertical swing detection model for the cutting boom is established. Then, a kinematic analysis of the vertical swing mechanism is made and formulae describing the geometrical relationship between the vertical swing of the cutting boom and the telescopic length of vertical hydraulic lift cylinders and vertical swing angle of the boom are presented. Various factors such as complexity of the calculation model, the difficulty of installing the sensor and the cost are compared for two methods. Finally, directly measuring the vertical swing angle of the cutting boom with a tilt sensor is decided to be the more simple and effective method. The detection sensitivity and the vertical cutting error of a tilt sensor are studied. Vibration tests on an EBZ160 roadheader were performed in a coal mine. The characteristic vibration frequencies are analyzed. A design of a vibration isolation mount for the tilt sensor is presented. It makes the detection device work more reliably under conditions where vibration is present and lays a foundation for the implementation of an automatic roadhead cutter. A tilt sensor is installed on an EBZ160 and an EBZ200, and experiments have been done in a coal mine. The re- suits show that the experimental result is favorable and achieves the goal of automatic control of the vertical swing of the cutting boom.展开更多
We investigated the behaviors of an active control system of two-stage vibration isolation with the actuator installed in parallel with either the upper passive mount or the lower passive isolation mount. We revealed ...We investigated the behaviors of an active control system of two-stage vibration isolation with the actuator installed in parallel with either the upper passive mount or the lower passive isolation mount. We revealed the relationships between the active control force of the actuator and the parameters of the passive isolators by studying the dynamics of two-stage active vibration isolation for the actuator at the foregoing two positions in turn. With the actuator installed beside the upper mount, a small active force can achieve a very good isolating effect when the frequency of the stimulating force is much larger than the natural frequency of the upper mount; a larger active force is required in the low-frequency domain; and the active force equals the stimulating force when the upper mount works within the resonance region, suggesting an approach to reducing wobble and ensuring desirable installation accuracy by increasing the upper-mount stiffness. In either the low or the high frequency region far away from the resonance region, the active force is smaller when the actuator is beside the lower mount than beside the upper mount.展开更多
基金support from China University of Mining and Technology (Beijing)Financial supports for this work provided by the National Hi-tech Research and Development Program of China (No.2008AA062201)
文摘Automatic profiling control using a boom-type roadheader requires an understanding of horizontal and vertical swing angles of the cutting boom. In this study the vertical angle of the cutting boom is discussed. First, a vertical swing detection model for the cutting boom is established. Then, a kinematic analysis of the vertical swing mechanism is made and formulae describing the geometrical relationship between the vertical swing of the cutting boom and the telescopic length of vertical hydraulic lift cylinders and vertical swing angle of the boom are presented. Various factors such as complexity of the calculation model, the difficulty of installing the sensor and the cost are compared for two methods. Finally, directly measuring the vertical swing angle of the cutting boom with a tilt sensor is decided to be the more simple and effective method. The detection sensitivity and the vertical cutting error of a tilt sensor are studied. Vibration tests on an EBZ160 roadheader were performed in a coal mine. The characteristic vibration frequencies are analyzed. A design of a vibration isolation mount for the tilt sensor is presented. It makes the detection device work more reliably under conditions where vibration is present and lays a foundation for the implementation of an automatic roadhead cutter. A tilt sensor is installed on an EBZ160 and an EBZ200, and experiments have been done in a coal mine. The re- suits show that the experimental result is favorable and achieves the goal of automatic control of the vertical swing of the cutting boom.
基金the Natural Science Foundation of China under Grant No. 50075029
文摘We investigated the behaviors of an active control system of two-stage vibration isolation with the actuator installed in parallel with either the upper passive mount or the lower passive isolation mount. We revealed the relationships between the active control force of the actuator and the parameters of the passive isolators by studying the dynamics of two-stage active vibration isolation for the actuator at the foregoing two positions in turn. With the actuator installed beside the upper mount, a small active force can achieve a very good isolating effect when the frequency of the stimulating force is much larger than the natural frequency of the upper mount; a larger active force is required in the low-frequency domain; and the active force equals the stimulating force when the upper mount works within the resonance region, suggesting an approach to reducing wobble and ensuring desirable installation accuracy by increasing the upper-mount stiffness. In either the low or the high frequency region far away from the resonance region, the active force is smaller when the actuator is beside the lower mount than beside the upper mount.
