In this paper, the model-based robotic control problem with disturbance attenuation (or robotic H∞ control problem), presented in Chen et all (1994), is extended to underactuated manipulators. The dynamic coupling between the links is used to control all manipulator’s free joints. A global explicit solution is found solving a minimax Bellman-Isaacs equation, generated via differential game theo...

In this paper, combined attitude control of an underactuated helicopter experimental system is considered. The controlled helicopter experimental system has two inputs and three outputs, namely, this system is underactuated. The combined attitude controller includes a nonlinear MIMO controller based on adaptive sliding mode control and non-adaptive nonlinear controllers. Control system stabilit...

We obtain an intrinsic vector-valued symmetric bilinear form that can be associated with an underactuated constrained mechanical control system. We determine properties of the form that serve as sufficient conditions for driving a constrained mechanical system underactuated by one control to an ǫ-neighborhood of rest from an arbitrary initial configuration and velocity. We also determine proper...

This is the second in a series of papers that exploit the physical coupling of tethered spacecraft to derive a propellant-free spin-up and attitude control strategy. We take a nonlinear control approach to underactuated tethered formation flying spacecraft, whose lack of full state feedback linearizability, along with their complex nonholonomic behavior, characterizes the difficult nonlinear co...

We introduce a decentralized attitude control strategy that can dramatically reduce the usage of propellant, by taking full advantage of the physical coupling of the tether. Motivated by a controllability analysis, indicating that both spin-up and relative attitudes are fully controllable by the reaction wheels, we report the first propellant-free underactuated linear and nonlinear control resu...

This paper introduces the iRobot-Harvard-Yale (iHY) Hand, an underactuated hand driven by 5 actuators that is capable of performing a wide range of grasping and in-hand repositioning tasks. This hand was designed to address the need for a durable, inexpensive, moderately dexterous hand suitable for use on mobile robots. The primary focus of this paper will be on the novel simplified design of t...

With the goal of improving the performance of underactuated robotic hands in grasping, we investigate the influence of the underlying coupling mechanism on the robustness of underactuated hands to external disturbance. This paper identifies unique behaviors in the hand’s response as a function of the coupling mechanism and the actuation mode the hand is operated in. Specifically, we show that i...

In this paper we explore state-of-the-art underactuated, compliant robot gripper designs through looking at their performance on a generic grasping task. Starting from a state of the art open gripper design, we propose design modifications, and importantly, evaluate all designs on a grasping experiment involving a selection of objects resulting in 3600 object-gripper interactions. Interested in...

The objective of this paper is to present systematic methods for throwing motion control of underactuated robots. The Pendubot, an underactuated two-link planar robot, is investigated as a dynamic model of the superior limbs for imitation of human throwing motion whose models are fundamentally underactuated in nature. The controller is designed based on input-output linearization and output zer...

This paper describes how to use backstepping to develop control laws to perform trajectory tracking for a nonlinear, underactuated surface vessel. The research extends earlier backstepping designs for underactuated vessels by explaining how to select outputs when generalized forces act on the vessel. The resulting control law can correct orientation errors to track linear trajectories and can t...