Drill sampling has been widely employed as an effective way to acquire deep samples in extraterrestrial exploration. A novel sampling method, namely, flexible-tube coring, was adopted for the Chang'e mission to acqui...Drill sampling has been widely employed as an effective way to acquire deep samples in extraterrestrial exploration. A novel sampling method, namely, flexible-tube coring, was adopted for the Chang'e mission to acquire drilling cores without damaging stratification information. Since the extraterrestrial environment is uncertain and different from the terrestrial environment, automated drill sampling missions are at risk of failure. The principles of drilling and coring for the lunar subsurface should be fully tested and verified on earth before launch. This paper proposes a test-bed for conducting the aforementioned experiments on earth. The test-bed comprises a rotary-percussive drilling mechanism, penetrating mechanism, drilling medium container, and signal acquisition and control system. For granular soil, coring experiments indicate that the sampling method has a high coring rate greater than 80%. For hard rock, drilling experiments indicate that the percussive frequency greatly affects the drilling efficiency. A multi-layered simulant composed of granular soil and hard rock is built to test the adaptability of drilling and coring. To tackle complex drilling media, an intelligent drilling strategy based on online recognition is proposed to improve the adaptability of the sampling drill. The primary features of this research are the proposal of a scheme for drilling and coring a test-bed for validation on earth and the execution of drilling experiments in complex media.展开更多
Experiments were conducted in an indoor soil bin filled with sandy clay loam soil. Tests were carried out with tillage tines to study the effect tool width on soil disturbance and draught. Depth of operation was held ...Experiments were conducted in an indoor soil bin filled with sandy clay loam soil. Tests were carried out with tillage tines to study the effect tool width on soil disturbance and draught. Depth of operation was held constant at 35 mm and then at 70 mm while speed was varied at three levels of 1.0, 3.6 and 9.0 km/h. The widths of the tines tested were 10, 20, 31, 40, 51, 88, 126, 163 and 200 mm. The cone penetration resistance of the soil varied from 400 to 600 kPa. Draught was measured with a load cell while soil disturbance was measured with a profile meter and meter rule. Draught increased at a decreasing rate with tine width. Quadratic models best fitted the data points with high R2 values. The increase in draught was affected by the forward speed since higher draught values were obtained at higher speed. Results show that the parameters of soil disturbance increased with increase in tine width, except height of ridge (hr), which did not show any specific trend. The specific draught was highest (10.63 N/cm) with tine T20 while Tine T1 had the least specific draught of 5.2 N/cm.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51105092)Introducing Talents of Discipline to Universities(111 Program,Grant No.B07018)+1 种基金Heilongjiang Postdoctoral Grant(Grant No.LBHZ11168)China Postdoctoral Science Foundation(Grant No.2012M520722)
文摘Drill sampling has been widely employed as an effective way to acquire deep samples in extraterrestrial exploration. A novel sampling method, namely, flexible-tube coring, was adopted for the Chang'e mission to acquire drilling cores without damaging stratification information. Since the extraterrestrial environment is uncertain and different from the terrestrial environment, automated drill sampling missions are at risk of failure. The principles of drilling and coring for the lunar subsurface should be fully tested and verified on earth before launch. This paper proposes a test-bed for conducting the aforementioned experiments on earth. The test-bed comprises a rotary-percussive drilling mechanism, penetrating mechanism, drilling medium container, and signal acquisition and control system. For granular soil, coring experiments indicate that the sampling method has a high coring rate greater than 80%. For hard rock, drilling experiments indicate that the percussive frequency greatly affects the drilling efficiency. A multi-layered simulant composed of granular soil and hard rock is built to test the adaptability of drilling and coring. To tackle complex drilling media, an intelligent drilling strategy based on online recognition is proposed to improve the adaptability of the sampling drill. The primary features of this research are the proposal of a scheme for drilling and coring a test-bed for validation on earth and the execution of drilling experiments in complex media.
文摘Experiments were conducted in an indoor soil bin filled with sandy clay loam soil. Tests were carried out with tillage tines to study the effect tool width on soil disturbance and draught. Depth of operation was held constant at 35 mm and then at 70 mm while speed was varied at three levels of 1.0, 3.6 and 9.0 km/h. The widths of the tines tested were 10, 20, 31, 40, 51, 88, 126, 163 and 200 mm. The cone penetration resistance of the soil varied from 400 to 600 kPa. Draught was measured with a load cell while soil disturbance was measured with a profile meter and meter rule. Draught increased at a decreasing rate with tine width. Quadratic models best fitted the data points with high R2 values. The increase in draught was affected by the forward speed since higher draught values were obtained at higher speed. Results show that the parameters of soil disturbance increased with increase in tine width, except height of ridge (hr), which did not show any specific trend. The specific draught was highest (10.63 N/cm) with tine T20 while Tine T1 had the least specific draught of 5.2 N/cm.