Advance Modeling of a Skid-Steering Mobile Robot for Remote ...

5.1 Identification of the Geometric and Inertial Parameters 65respect to our purposes.Moreover, to obtain the height of the CoM, i.e. the z coordinate of the vectors p i , the robotis tilted both on the left and right side until it reaches almost an equilibrium point, i.e. itdoes not fall on any side. Then, two straight lines perpendicular to the ground surface canbe drawn starting from the wheel/ground contact point and the height of CoM with respectto the floor can be found purely by the geometric intersection of the two lines, as depicted inFigure 5.1(b). It is worth noticing that such estimation of p iz , which is constant for the fourwheels, is reliable since we are considering the z axis of the robot frame perpendicular to theplane given by the four contact points.(a)(b)Figure 5.1: (a) Measuring the CoM position on x-y plane; (b) Measuring the CoM height.Tab.5.1 list all the geometric parameters defined above, where the contact points are numberedclockwise starting from the right-rear wheel to the left-rear wheel.i p xi p yi p zi1 -0.15 0.18 -0.232 0.13 0.18 -0.233 0.13 -0.18 -0.234 -0.15 -0.18 -0.23Table 5.1: Table of the geometric parameters.To have a first estimation of the robot tensor of inertia with respect to its principal axes, themain components are measured and weighted, and their tensors of inertia are then calculated