In this paper, we introduce a method that provides a nonlinear noncollocated output for trajectory tracking of a flexible one-link robot. The link is modeled as a finite-order Lagrangian system obtained from truncated modal analysis. This noncollocated output is derived based on viewing a flexible link robot arm as an underactuated mechanical system and then applying an appropriate change of co...

In this paper we develop an intelligent controller on the basis of Genetic Algorithms for the stabilization of a class of Underactuated Mechanical Systems. First we develop a static State Feedback Controller with inner noncollocated partial feedback linearization loop to stabilize the nominal system. Second, we develop a Genetic algorithm controller to maintain system stabilization and to adapt...

The increasing interest in autonomous marine systems and related applications has motivated, among others, the development of systems and algorithms for the dynamic positioning of underactuated marine vehicles (ships, surface vessels, underwater vehicles) under the influence of unknown environmental disturbances. In this paper we present a state feedback control solution for the navigation and ...

A three dimensional reorientation problem for an underactuated multi-body spacecraft is studied. Formulae for approximating the change in orientation of the base body of the spacecraft, induced by appropriately constructed small amplitude periodic joint motions, are derived. These formulae are used to construct joint motions that cause a desired reorientation maneuver to be performed within a p...

A new crane design, labeled ”SpiderCrane”, is proposed to handle fast load displacements. Its main particularity is the absence of heavy mobile components. The system beeing underactuated, its control is challenging. Hence, as a step towards easier and more efficient control, this paper proposes a dynamic model and investigates the two control-relevant properties of flatness and observability. ...

We investigate the boundary stabilization of a particular subset of 3×3 linear hyperbolic systems with varying coefficients on a bounded domain. The system is underactuated since only one of the three hyperbolic PDEs is actuated at the boundary. The setup considered in the paper occurs in control of multiphase flows on oil production systems. We use a backstepping approach to design a full-stat...

Based on a recently developed ”generalized averaging theory,” we present a generic approach for the design of stabilizing feedback controllers for biomimetic locomotive systems. The control laws exponentialy stabilize in the average, and they apply to a very wide class of systems. Two examples are given: a ”kinematic biped” that demonstrates how our theory handles discontinuities, and the snake...

In this note, we introduce cascade normal forms for underactuated mechanical systems that are convenient for control design. These normal forms include three classes of cascade systems, namely, nonlinear systems in strict feedback form, feedforward form, and nontriangular quadratic form (to be defined). In each case, the transformation to cascade systems is provided in closed-form. We apply our...

Two control problems related to a particular underactuated mechanical system, the reduced size US Navy crane, are addressed. The open-loop motion planning problem is solved by showing that the model of the crane is differentially flat with a flat output comprising the coordinates of the load as its first components. The closed-loop global asymptotic stabilization of equilibria is achieved using...

This paper addresses point stabilization for the extended chained form (ECF), a control system that may be used to model a number of mechanical underactuated systems. A control law is proposed, based on well-known hybrid open-loop/feedback techniques, which exponentially stabilizes the origin of a dynamic extension of the ECF and ensures a degree of robustness to additive disturbance terms that...