Stabilization of the wheeled inverted pendulum on a soft surface
This work addresses stabilization challenges for robotics on uneven terrain, but it appears incremental as it builds on existing control methods without major breakthroughs.
The researchers tackled the problem of stabilizing a wheeled inverted pendulum on soft surfaces using a PID controller, finding semi-stable stationary solutions in their mathematical model that appear as limit cycles in simulations due to numerical errors or external perturbations.
We study dynamics of an wheeled inverted pendulum under a proportional-integral-derivative controller on horizontal, inclined and soft surfaces. An oscillatory area and conditions of the stability for the control are shown on the phase portraits of the dynamical systems. Particularly, we study a differential inclusion for moving on the soft surface, and we find semi-stable stationary solutions in our mathematical model. Due to rounding errors of the numerical modelling or external perturbations of robotics equipment the semistability looks as a limit cycle in simulations.