Funnel Control Under Hard and Soft Output Constraints (extended version)
This work addresses safety-critical control for robotics and autonomous systems, offering an incremental improvement by integrating hard and soft constraints in funnel control.
The paper tackles the problem of controlling uncertain nonlinear systems under both hard safety and soft performance constraints by proposing a funnel control method that plans constraint-consistent funnels and designs a robust controller, verified with a simulation of a mobile robot tracking an object within a safe space.
This paper proposes a funnel control method under time-varying hard and soft output constraints. First, an online funnel planning scheme is designed that generates a constraint consistent funnel, which always respects hard (safety) constraints, and soft (performance) constraints are met only when they are not conflicting with the hard constraints. Next, the prescribed performance control method is employed for designing a robust low-complexity funnel-based controller for uncertain nonlinear Euler-Lagrangian systems such that the outputs always remain within the planned constraint consistent funnels. Finally, the results are verified with a simulation example of a mobile robot tracking a moving object while staying in a box-constrained safe space.