Switched Safe Tracking Control of Chain Tensioning System With Multiple Disturbances and Kinematic Constraints

In armored face conveyors, one of the significant challenges of moving from manual to automated chain tensioning is the safety of the interaction between the controlled system and complex environment. Multiple disturbances might put an automated chain tensioning system (CTS) at a high risk of collision and chain jumping due to excessive position/velocity in tension control. Therefore, a switched safe tracking control is proposed for the CTS with multiple disturbances and kinematic constraints. A hybrid switched tension/position control with hysteresis autonomous switching strategy is integrated into the safe tracking scheme. The switching control method enables the CTS to perform autonomous motions to follow a predefined safe trajectory when the position exceeds the safe bound. The barrier Lyapunov function is utilized in the controller design to prevent the violation of velocity constraints. Friction compensation, parameter adaption, and improved integrator are employed to deal with the multiple disturbances. To avoid the transient overshoot/oscillation around switching points, the negative influence of multiple disturbances is considered while designing the integrator term and autonomous switching strategy. Finally, comparative experiments are conducted to verify that the proposed control scheme can achieve excellent tension tracking performance while preventing the violation of kinematic constraints in multiple situations, such as startup phase, operation phase, and strong disturbance.