Estimation of Wheel-Contact State of a Robotic Vehicle

A method of estimating the state of contact between (1) the wheels of a robotic vehicle equipped with a rocker-bogey suspension and (2) the ground has been devised. The contact-state information is used to estimate the position of the vehicle with an accuracy greater than that achievable by simple odometry and inertial sensing when the vehicle moves over undulating or bumpy terrain under conditions in which processing of visual odometry information is infeasible or undesirable. The contact-state information can also be used to increase understanding of those aspects of design and operation of the vehicle that affect stability and traction, as affected by the configuration of the rocker-bogey and steering mechanisms. The method in its original form is meant to be applied to Rocky-7 (see figure) - a "rover"-type vehicle used in research on robotic-vehicle concepts for the exploration of Mars. The method is also potentially applicable to terrestrial robotic vehicles that could be used in field operations in agriculture, mining, and other industries.