| After coal mine disaster, rescue robots instead of the rescuers completely or partly enter into the mine disaster area to carry out environment exploring, searching and rescuing tasks, which are helpful to improve rescue efficiency and decrease casualties, and it's grateful for realistic significance and social significance. After disaster, especially the gas and coal dust explosion accidence, the space-restricted, unstructured underground terrain environment and explosive gas atmosphere require coal mine rescue robots with good surmounting obstacle performance and explosion-proof property. The most important task of the rescue robot is access to the mine disaster area smoothly. Besides research on the mobile mechanisms of the coal mine rescue robot are principal, crucial and difficult, so the mobile mechanisms for the coal mine rescue robots was studied in this dissertation.In this dissertation, the application and necessary function of coal mine rescue robots were discussed primarily. Underground roadway and regions where the robots would reach were determined. Unstructured terrain environments which the robots would overcome were studied, and the terrain features were extracted and simplified. According to above reasons, performance requirements and indexes of coal mine rescue robots were presented. The 3D real terrain was simulated by using operational methods of fractal interpolation and cubic spline interpolation, which could supply the experiment field for the robot virtual prototype, and beneficial for dynamic simulation and optimization of mechanisms. In the lab, some adjusted mechanism test platforms, including ditch simulation test platform, rugged terrain simulation test platform and step-slope combination simulation test platform were developed. These platforms combined with the motion capture system could be used to test and evaluate mechanism performance of the robot prototypes comprehensively.For studying on the robot mobile mechanisms which were suitable for the underground mine terrain environments, graphical representation and naming rules of the wheel type and track type mobile mechanism were suggested. The mechanism deductions and graph topology of the wheel and track type mechanisms were carried out, and the basic configurations were deducted. The tracks were introduced into the rocker-type robot mobile system, and then various configurations of the rocker-type track suspensions were obtained. This would prepare for studying on robot mobile mechanisms which were suitable for the underground mine terrain environments.For discussing the application of the track type mobile mechanism, according to the basis track type configurations, dynamics and kinetics of two tracks type (T type), four tracks with two arms type (TA type) and six tracks with four arms type (T2A type) were studied, and their performance and best capabilities of surmounting obstacles, including step and slope-climbing, channel-crossing were analyzed. Five prototypes were developed by using three mechanisms configurations. Adopting the TA type mechanism, CUMT-IIA and CUMT-IIB coal mine rescue robots were designed, which employed the relay communication and fiber communication respectively. The mechanical performance tests were carried out on the test platform and rough terrain. In JIAHE coal mine of XUZHOU coal mining bureau tested the CUMT-IIA and CUMT-IIB robots.Research and tests results were obtained. First, Track type mobile mechanism had good overcoming structured terrain such as steps and ditches. Second, it needed enough large external dimensions to meet the obstacle-surmounting index. Third, small-sized track type mechanism would be jammed on the rough terrain, because of its low chassis, and the robot would not run if the sand and little stone entered into the tracks.In order to explore the mobile mechanisms those satisfy the complex mine rugged terrain, and compensate for the mobile mechanism of small size track, the rocker wheel type robot was studied. Based on the evolution of robot mobile mechanism, the components of rocker type four-wheel robot mobile mechanism were developed, and differential mechanism styles including six gear-type differential mechanisms were implemented. The experiment on terrain adaptability and surmounting obstacle performance of the robot prototype were carried out. Experiments results indicated that the prototype had good terrain adaptability and strong obstacle surmounting performance. However, the shortcomings of the rocker type wheel robots were as follows. First, the ditches width that the robot could cross was restricted by the wheels diameter. Second, the performance of stair-climbing was not well.Combining the advantages of track type and rocker type four wheels mobile mechanisms, surmounting their deficiencies, the tracks instead of wheels were introduced into rocker-type robot mobile system, and then various configurations of rocker-type track suspensions were obtained. According to the performance and structure requirements to the terrain environment and area environment after disaster, two W-shaped track suspensions were selected as study objects. The first one(d5 mechanism) adopted a whole track limited into W shape by using bend wheels. The second one(d7 mechanism) composed of two tracks, which formed W shape and rotated together, and the rear main tracks of the W-shaped tracks were longer than the front ones. The mobile mechanism-terrain mechanics, kinematics and dynamics of differential drive were analyzed.The rocker type track robot prototype was designed and developed by using d5 mobile mechanism and NGWW type planetary gear differential mechanism. The motion characteristics were analyzed, and the mechanical performance tests were carried out on the test platform and rough terrain in field. Experiment results indicated that the rocker-type track mobile platform had good passive adaptability to unstructured terrain environment and strong obstacles-surmounting capabilities; but the bend wheel structure influenced the obstacles-surmounting performance.On the basis of above research, the robot prototype was made by using d7 mechanism and link type differential mechanism. And the strength check of flameproof enclosure and track suspension were carried out. The prototype's obstacles-surmounting capabilities including ditch-crossing, step and stairs-climbing were analyzed. Mechanical performance tests were carried out on the test platform and on the rough terrain in field. The capability analysis and prototype test results indicated that d7 mechanism overcame the shortcoming of d5 mechanism. The rocker-type W-shaped track mobile platform had excellent passive adaptability to unstructured terrain environment and strong obstacles-surmounting capability. The prototype could climb up a 320mm-high step, climb down a 520mm-high step, climb up a flight of 150mm×280mm stairs, cross a 490mm-wide ditch. The rocker-type W-shaped track mobile platform met obstacles-surmounting performance requirements to the unstructured terrain environment.At last, when the robot moving and surmounting obstacles, the 3D coordinate of the feature points on the robot platform were measured by using motion capture system. And the displacement, velocity and acceleration and their curves of the feature points and parts could be obtained. Tests results proved that the main body had lower motion amplitude and smaller vibration than the track suspensions on both side, and the robot could be operated smoothly and steadily.
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