Stairs-climbing Capacity of a W-Shaped Track Robot

Stairs-climbing capacity is an important index for obstacle-overcoming performance for coal mine rescue robot. For studying on stairs-climbing capacity of the coal mine rescue robot with W-shaped track suspensions, theoretical analysis, kinematics simulations and tests on real stairs have been carried out. According to sizes of normal stairs in reality, there are two climbing situations: (1) the first track section and the third track section climb the nosings of the two adjacent steps or two septal steps successively, (2) the front and rear tracks climb two nosings simultaneously. There are two critical states: (1) the first and third track section just touch the nosing of two interval steps, (2) the first and third track section barely touches the nosings of the adjacent steps. According to the two states, equation sets which describe the relationship between tread depth and riser height are deduced. According to the physical dimensions of the robot, the relation curves are drawn corresponding to the equation sets. Conditions of the two climbing situations are obtained. The stairs-climbing are simulated on RecurDyn, and tests on a simulated staircase test platform in laboratory and on real stairs in and outside the building are carried out. The simulation and tests results are in accordance with the theoretical analysis. Research in this paper is conducive to optimizing the shape and size of the W-shaped track suspension according to the parameters of the stairs, and also contributes to guiding the application of the robot with a W-shaped track moving mechanisms