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

6.2 Simulation Results 93odometry point of view, i.e. moving along a straight line and swiveling in place. The twotypes of motion are performed by providing different control velocities v x , ω z and setting λ maxto different orders of magnitude, i.e. λ max = 1, 10 −1 , 10 −2 , 10 −3 , 10 −4 . However, the value ofλ max does not affect the overall behavior when moving along a straight line, i.e. providing thecontrol v x 0, ω z = 0, but it slightly affects only the wheel slipping when accelerating/decelerating,as depicted in Figure 6.8. Conversely, the value of λ max significantly affects thesystem behavior when the robot is turning, especially during sharp turns, as it was expected.Figure 6.9 depicts two examples of the results obtained when swiveling in place, respectivelyfor the two extreme cases λ max = 1, 10 −4 .Figure 6.8: Simulation result for moving along a straight line at v x = 1 m s with λ max = 10 −4 .Because of the absence of information about the real robot motion, i.e. its position andvelocity, the results obtained during the simulation can not be evaluate from a quantitativepoint of view. However, by looking at the results depicted in Figure 6.8, 6.9 from a qualitativepoint of view, the following considerations con be done:• The model qualitatively reproduces the real robot motion as it is coherent with the controlcommands provided to the model, both regarding the position and velocity errors.• The model qualitatively reproduces the expected skid-steering motion as it provides arelatively small lateral velocity v y when turning, due to the robot skidding properties.• The model qualitatively reproduces the real robot jerky motion, providing both the