Robust output maneuvering for a class of nonlinear systems

Abstract

The output maneuvering problem involves two tasks. The first, which is the geometric task, is to force the output to converge to a desired path parametrized by a continuous scalar variable θ. The second task is to satisfy a desired speed assignment along the path. The main concern is to satisfy the geometric task. However, the speed assignment will ensure that the output follows the path with sufficient speed. A recursive control design technique is developed for nonlinear plants in vectorial strict feedback form of any relative degree. First the geometric part of the problem is solved. Then an update law is constructed that bridges the geometric design with the speed assignment. An extra degree of freedom is provided for an operator to specify the speedθ. A computer simulation with a marine vessel is performed to illustrate the design. Copyright c°2002 IFAC

Model predictive path-following for constrained nonlinear systems

“…And additionally, it should guarantee that the system moves as close as possible to and along the path through the state space. In fact, path-following provides a suitable framework for different problem formulations: Ship or flight course control, the car-parking problem or the control of robots and CNC-machines [4], [13]. It is also appropriate for control problems arising in batch crystallization [11].…”

“…Existing path-following approaches are limited, since input constraints are not explicitly considered [1], [2], [13]. In this contribution we propose a solution to the path-following problem for nonlinear systems subject to constraints on inputs and states.…”

“…We also give sufficient stability conditions. While other works on path-following consider output-feedback [1], [2], [13], we rely on state feedback. In Section IV we illustrate our scheme by simulations of an autonomous vehicle.…”

Coordinated Path Following for Mobile Robots Using a Virtual Structure Strategy with Model Predictive Control

“…The derivations can be found in [23]. It has to be noted that (3) and (6) are not valid if cusp or singularity at the robot's path is present. Furthermore, to deal with path following problems, we introduce an additional variable state η e where η e =ṡ c − u c and u c is the desired forward velocity of the whole formation moving along the reference path.…”

“…to reach and to follow a geometric path, i.e., a manifold parameterized by a continuous path variable s (called a geometric task), while a secondary goal is to force the object moving along the path to satisfy some additional dynamic specifications (called a dynamic assignment task) [5]. This dynamic behavior can be determined by time, speed, or acceleration assignments [6]. This setting is apparently more general than the trajectory tracking problem in such a way that the path variable s is left as an extra degree of freedom for the secondary goal.…”