Robust adaptive terminal sliding mode-based synchronised position control for multiple motion axes systems

A novel robust adaptive terminal sliding mode position synchronised control (RATSMPSC) approach is developed for the operation of multiple motion axes systems. The RATSMPSC structure is designed in cross-coupling error space to stabilise position tracking of each axis while coordinating its motion with other axes in finite time. The criterion for the design is that any position error and synchronisation error should be converged to zero in finite time simultaneously. An adaptive mechanism is employed to estimate controller parameters so that the request of prior knowledge of the bounds of system uncertainty can be alternatively resolved. The corresponding stability analysis is presented to lay a foundation for a theoretical understanding to the underlying issues as well as safely operating real systems. The proposed approach has strong rejection capacity against external disturbances and robustness to deal with model uncertainties. An illustrative example is initially simulated to demonstrate the performance of the approach.