Structure Design And Motion Study Of Tracked Mobile Robot Used In Emergency Relief

While frequent disasters in recent years, such as terrorist attacks and natural catastrophes,cause huge life and property losses, fast, effective and safe rescue of the injured is treated as thefirst mission after the disaster. At the present time, searching and rescuing equipment areusually units and devices that can be used to conduct airborne survey and/or perform searchingand rescuing at the sites. The first task can be carried out using manned or unmannedhelicopters; however, the second task appears to be more difficult due to the complicatedsituation/environment after the disaster: the on-site searching and rescuing devices need abreakthrough in environmental adaptability and mobility, etc. A portable and transformablemulti-tracked mobile robotic system may be suitable for such purpose, which has beencomprehensively investigated in terms of structures and motion characters.A transformable double-tracked mobile robot (TDMR) controlled by adaptive mechanismis designed, which can operate adaptively according to the shape of the ground, crossingobstacles and climbing stairs. The adaptive mechanism consists of a set of planetary gears and aquadrilateral mechanism. The transformation of quadrilateral mechanism and the action oftracks are achieved by planetary gears according to the forces applied to the tracks, making thequadrilateral mechanism adjust itself to the terrain. However, the mobility of the robot is ratherlimited as a result of the large dimension.A super tracked mobile robot (STMR) with parallelogram mechanism is designed, with themain structure consisting of two symmetrically distributed parallelogram mechanisms. One sideof the parallelogram is the chassis and the other three are track mechanisms that aresynchronously driven by coupling shafts. The robot can move in three different modes: track,leg and wheel, making it easier to operate in a complex environment.Moving characteristics of the STMR, particularly in the obstacle-navigation process, werestudied via calculating its centroid position and swing angle. The movement of the STMR wasalso optimized by controlling the posture and swing angle concurrently, in order to achieve asmooth action during the operation. The dynamics model for the STMR was built usingNewton-Euler method, by which the driving torque and dynamic stability for the STMR tomove across the steps were analyzed. Simulation analysis revealed the characteristics of thedriving torque as a function of time. Based on the requirements of system stability and real-time performance, a dual-layercontrol system, composed of a mainboard and a control driver board, was designed for STMR.The verification test showed that the movement optimization was quite successful such thatSTMR can perform given tasks as expected.STMR robot has very good obstacle-crossing ability and movement stability, with multiplemoving styles and flexible transformation capability, making it easier to adapt to the complexenvironment.