Hierarchical fast terminal sliding mode control for a self-balancing two-wheeled robot on uneven terrains

Abstract

Self-balancing two-wheeled robots (TWRs) have attracted significant attentions over the last decade around the world. However, the traditional controller performs worse when TWR is driven under severe traveling conditions like steep slopes, speed bumps and other uneven terrains on practical pavement, which leads to potential security issues. This paper takes uneven terrains into consideration in system modeling and presents a hierarchical fast terminal sliding mode approach in controller design. The sliding mode controller system is proven asymptotically stable in terms of Lyapunov stability theorem. According to intensive simulation results, the proposed control approach is effective to hold TWR balanced and track desired velocity by numerous analyses. Simultaneously, the control system can also reject disturbances from external environment and reduce shuddering through uneven terrains.