Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Globally Robust Sliding Mode Command Tracking Under Input Bounds Using a Time-Optimal Sigmoid
Submission Author:
Davi Antônio dos Santos , SP , Brazil
Co-Authors:
Davi Antônio dos Santos
Presenter: Davi Antônio dos Santos
doi://10.26678/ABCM.COBEM2021.COB2021-0280
Abstract
Mechatronics systems usually operate under two crucial antagonistic conditions: disturbances and actuator constraints. On the one hand, the disturbances typically require a high-magnitude control action to overcome their effects, while, on the contrary, the control action must be sufficiently small to avoid saturating the actuators. Moreover, the system operation is often required to be smooth to avoid vibration and consequent wearing. In this context, the present paper investigates the smooth-command-tracking control of a continuous-time second-order system subject to disturbance and actuator constraints. To cope with the disturbance, we adopt the global first-order sliding-mode control, by which disturbance invariance can be ensured from the initial time on. Concerning the input constraint as well as the smooth command tracking, we generate a second-order polynomial S-curve output trajectory connecting the initial point to the target with an acceleration-cruise-deceleration profile. The final time of the S-curve trajectory is designed as a minimum value constrained on the control bounds and on a terminal tolerance about the specified target point. This optimization problem is convex as well as unidimensional design space and, for this reason, can be efficiently solved using a simple bisection algorithm. The method is illustrated by numerical simulations which show its effectiveness to provide global robustness, smooth operation, and saturation avoidance.
Keywords
global sliding mode control, Trajectory generation, Mechatronics Systems
