| The kinematic and dynamic simulation technology for the mechanical system is the emerging technology. In the tracked mobile robots'reseach field, the technology is widely used because of the great advantage in realizing the universal property, adaptability of terrain, portability and microminiaturization of tracked mobile robots. Based on the running theory of tracked mobile robots, the dynamic simulation research of the tracked mobile robot is carried in this paper by the analytical software of multibody dynamics Recurdyn.The difficulty of the paper is establishing the dynamic model of the tracked mobile robot. Firstly, the geometry model of the high/low-speed tracked mobile robot's body is constituted by using the CAD module in the RecurDyn software and selecting the rational material parameter. Secondly, the geometry model of the high-speed tracked mobile robot's mobile mechanism which is composed of the driving wheels, guide wheels, weight-carrying wheels and balance-elbows and the geometry model of the low-speed tracked mobile robot's mobile mechanism which is composed of the driving wheels, guided wheels, weight-carrying wheels, track supporting wheels and tracks are constructed step by step through compiling the geometry bodies several times. Thirdly, the whole vehicle body's geometry model of high/low-speed tracked mobile robot is constructed according to geometry relationship assemble of each two parts. Both structure constraint and force constraint which are much more suited for reality are added among every components and the dynamic model of high/low-speed tracked robot is established on the base above.Taking the dynamic model of low-speed tracked mobile robot for example, the motion of climbing slope and steering will be simulated and analyzed. First of all, on one hand, based on the Beck's theory, selecting the Heavy Clay pavement with the 7.5°and 15°-slope angle, the changing discipline of displacement, velocity, acceleration and driving torque of the tracked mobile robot's model are obtained under the IF function movement constraint applied on the driving wheels during the simulation process of the climbing slope movement. On the other hand, analyzing the driving torque of the model by choosing the slope(7.5°or 15°) and two different kinds of pavement which are the Heavy Clay and the Clayey Soil, analyzing the driving torque of the model by choosing the pavement(Heavy Clay or Clayey Soil ) and two different kinds of slope (7.5°and 15°), verifying the rationality of the theoretical analysis that simplifying the driving wheels-tracks as pulleys-belts , the rationality of the IF function movement constraint that is added to the driving wheels , the feasibility of dynamic model.Secondly, the double sides-back wheels are adopted for the absolute driving. The STEP function movement constraint is added to the driving wheels separately during the simulation process of steering movement .On one hand, setting up the unyielding pavement, the 90°steering in place is realized. The changing discipline of the angular displacement, angular velocity, angular acceleration to the tracked mobile robot and angular velocity, driving torque of the double sides- driving wheels are obtained. On the other hand, setting up the Heavy Clay pavement, the 90°bend steering and the 90°-steering on the slope are realized. The changing discipline of the linear displacement (the 90°-steering on the slope), angular displacement, angular velocity, angular acceleration to the tracked mobile robot and angular velocity, driving torque of the double sides- driving wheels are obtained, verifying the rationality of the STEP function movement constraint that is added to the driving wheels, illustrating further the feasibility of the established dynamic model of low-speed tracked mobile robot.The simulation method is reliable to some extent, and it offers theoretical foundation for the simulated modeling and modularized design of tracked mobile robots in the future. |
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