This paper presents new techniques for controlling the motion of an underactuated vehicle when disturbances are present and only imperfect state measurements are available for feedback. A state feedback controller is developed and then it is converted to an imperfect state measurement feedback controller. The state feedback tracking control law uses an H∞-optimal design and produces a locally e...

Differential flatness is a property which substantially reduces the difficulty involved in generating dynamically feasible trajectories for underactuated robotic systems. However, there is a large class of robotic systems that are not differentially flat, and an efficient method for computing dynamically feasible trajectories does not exist. In this paper we introduce a weaker but more general ...

Recently, passivity based control theory (energy approaches) has undergone a breakthrough in dealing with underactated mechanical systems with two successful and similar tools, controlled Lagrangians and controlled Hamiltanians (IDAPBC). Because of the complexity, successful case studies are lacking, for example, MIMO, underactuated and unstable systems. The seminal paper of controlled Lagrangi...

In this work it is presented the adopted solution in the electronic control lab of a university department to cover the existing gap, both in teaching and research, related to integrated tools for identification, design, simulation and execution of control solutions for underactuated nonlinear prototype systems. The proposed development system includes both hardware and software components whic...

An appropriate control scheme must be used to alleviate nonlinearities and uncertainties for the plant system. However, this is not a trivial task due to the fact that modeling the nonlinearities such as friction and stiction are always inaccurate. For this, adaptive and robust control approaches are preferable. Thus, this paper investigates a new suggested controller scheme namely Nominal Char...

This paper presents a coupled and directly self-adaptive underactuated (CDSA) grasp mode, which has hybrid functions: coupled grasp and directly self-adaptive grasp. A novel multipulley-belt ̄nger mechanism with springs is designed based on CDSA grasp mode. Compared with traditional coupled underactuated ̄ngers or directly self-adaptive underactuated ̄ngers, the grasp process of the new ̄nger is mo...

This paper presents the control of an underactuated two-link robot called the Pendubot. We propose a controller for swinging the linkage and rise it to its uppermost unstable equilibrium position. The balancing control is based on an energy approach and the passivity properties of the system.

Underactuation is ubiquitous in human locomotion and should be ubiquitous in bipedal robotic locomotion as well. This chapter presents a coherent theory for the design of feedback controllers that achieve stable walking gaits in underactuated bipedal robots. Two fundamental tools are introduced, virtual constraints and hybrid zero dynamics. Virtual constraints are relations on the state variabl...

Abstract: This paper presents a nonlinear H∞ control law for underactuated mechanical systems with input coupling. Apart from the controlled degrees of freedom (DOF), the proposed controller considers the dynamics of the remaining DOF in the cost variable, which allows to stabilize them. The underactuated mechanical system is normalized to obtain a diagonal inertia matrix allowing to weigh with...

Path following of underactuated surface vessels is important practice in ship motion control field. Some of current studies have restrictions on forms of desired trajectory of which straight line or sinusoid curve was excluded. In this paper, adaptive robust controllers for path following of underactuated surface vessels are proposed based on hierarchical sliding mode method which suits various...