Constraint control of a flexible-link manipulator

This paper presents a constrained control strategy for a 2-DoF flexible manipulator, modeled using the Euler-Bernoulli beam theory and the assumed mode method. The manipulator's dynamics are represented through a closed-form equation that accounts for flexural effects, actuator saturation, joint limits, and velocity bounds. The proposed control strategy separates stabilization from constraint satisfaction by employing a vibration control method for stabilization and a Trajectory-based Explicit Reference Governor (ERG) to ensure constraint compliance. The ERG adjusts the applied reference to direct the manipulator toward a desired state while maintaining the constraints, using a dynamic safety margin (DSM) and a navigation field (NF). The effectiveness of the approach is demonstrated through numerical simulations, which show successful manipulation while respecting the constraints.