Vibration effects on pickforce sensing

Pickforce sensing is a method demonstrating a promising future in automating coal mining machines. The method is based on the ability to determine the vertical location of a rotary cutting machine from the force measured at the point of contact between the machine and the coal seam. A major problem that may degrade the reliability of the pickforce data is vibration and is the major concern of this study. To analyze the effects of vibration on pickforce sensing, a vibration model of the cutting process is first developed. Then, a stochastic model of the coal seam is constructed. Subsequently, the vibration model is simulated in three stages. In these stages, the machine is assumed to be cutting through three types of coal seam: homogeneous, predetermined heterogeneous, and heterogeneous stochastic model. The first stage is conducted to prove that pickforce data always contains a degree of phase shift between successive half revolutions. This eliminates the effect of repetitive or orderly vibration that may mask the pickforce data. In addition, both the first and second stages are conducted to find ways to improve the reliability of pickforce data by adjusting a few parameters within the machine. The third stage is conducted to prove that the chaotic appearance of the pickforce data does not eliminate the features that are used to determine the vertical location. The present study concludes that vibration has a minor effect, and that pickforce sensing can be improved by adjusting some parameters of the cutting machine