| The mechanical system of wheeled mobile robot(WMR) involving kinematics and kinetics is the foundation to control robot accurately. The purposes of designed mobile robot mostly depend on specific mechanical construction, whose mobility affects the performance and functions of the robot directly. The mobility of mobile robot is investigated thoroughly in this dissertation, and the prototypes of WMR with differential driving and front wheel steered driving configrations are designed and developed. The main contents are carried out as follows.(1)Using velocity constraining equations along radial and axial directions, the velocity stacking equations of mobile robot with several wheels for driving and supporting are established. The affecting conditions are summarized according to the analysis of velocity stacking equations. Then the derived velocity equations of offset steering wheel come to a conclusion that the addition of offset steering wheel served as free wheel doesn't impact on the mobility of WMR. The inverse and forward solutions drawn from the velocity stacking equations present the relation between motion status value of WMR and that of wheels.(2) Two types of physical prototypes, namely the XAUT.AGV100 of differential driving configuration and XAUT.AGV5000 of front wheel steered driving configration, are developed based on the kinematics analysis of two typical constructions of WMRs. The steering principle, design scheme, design method for the driving system, and the composition of the control and navigation system are mainly discussed. The improvement for conventional buffering system of free wheel is introduced for the differential driving configuration with four wheels. The driving system for the WMR is designed based on kinetics model. The dead reckoning equation and motion control algorithm are derived for the prototype.(3) The incontinuity of geometric parameters of conjunction point between linear path and curved path needs a sudden change in velocity of driving motors and angular position of steering motors, this make it impossible for robot to follows the path accurately owing to the limitation of dynamic characteristics of motors. Consequently, the performances of WMR are affected. So a path with continuous curvature is deduced in section 5 in order to guarantee successive variation in velocity of driving and steering motors at the conjunction of different type paths, and the feasibility to control motors is promising.(4) The contact factors between wheel and road surface have great influences over motion performances of WMR, when WMR moves on actual road. The sliding characteristics of front wheel steered driving configuration with three wheels WMR is studied in section 6. Resting on kinetics model with steady state circle motion, and the parameters of motion measured from experimental platform, the sliding stiffness parameters are obtained by iterative solution of the kinetics equations based on the Newton-Raphson numeric algorithm, which provides a reference to experimentally study on transverse sliding characteristics.(5) The WMR is vulnerable to be affected by lateral impact as side impact force, wind force and stochastic hump on the road. Based on the study on lateral sliding characteristics of WMR, the orientation stability in linear motions is studied aiming at front wheel steered driving configuration with three wheels WMR. The conditions for orientation stability in linear motions are achieved from analysis of planar motion differential equations, which are testified and experimentally evaluated successfully on the XAUT.AGV5000.The kinematics and kinetics discussed in the paper have been applied to the design and development of prototypes. The study on mobility and path tracing performances has been successfully demonstrated on the developed prototypes. At present, two prototypes have been successfully put into use in engineering applications and scientific teaching, which provides the solid basis for the application and associated technical study for WMRs.
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