Brachiation on a Ladder with Irregular Intervals

We have previously developed a brachiation controller that allows a two degree of freedom robot to swing from handhold to handhold on a horizontal ladder with evenly space rungs as well as swing up from a suspended posture using a target dynamics controller. In this paper, we extend this class of algorithms to handle the much more natural problem of locomotion over irregularly spaced handholds. Numerical simulations and laboratory experiments illustrate the effectiveness of this generalization

A Hybrid Swing up Controller for a Two-link Brachiating Robot

In this paper, we report on a hybrid scheme for regulating the swing up behavior of a two degree of freedom brachiating robot. In this controller, a previous target dynamics controller and a mechanical energy regulator are combined. The proposed controller guarantees the boundedness of the total energy of the system. Simulations suggest that this hybrid controller achieves much better regulation of the desired swing motion than the target dynamics method by itself

Passive dynamic swing locomotion for a 6dof coplanar articulated chain

Ingeniero (a) ElectrónicoPregrad

Stabilization Control for the Giant Swing Motion of the Horizontal Bar Gymnastic Robot Using Delayed Feedback Control

Open-loop dynamic characteristics of an underactuated system with nonholonomic constraints, such as a horizontal bar gymnastic robot, show the chaotic nature due to its nonlinearity. This chapter deals with the stabilization problems of periodic motions for the giant swing motion of gymnastic robot using chaos control methods. In order to make an extension of the chaos control method and apply it to a new practical use, some stabilization control strategies were proposed, which were, based on the idea of delayed feedback control (DFC), devised to stabilize the periodic motions embedded in the movements of the gymnastic robot. Moreover, its validity has been investigated by numerical simulations. First, a method named as prediction-based DFC was proposed for a two-link gymnastic robot using a Poincar section. Meanwhile, a way to calculate analytically the error transfer matrix and the input matrix that are necessary for discretization was investigated. Second, an improved DFC method, multiprediction delayed feedback control, using a periodic gain, was extended to a four-link gymnastic robot. A set of plural Poincare maps were defined with regard to the original continuous-time system as a T-periodic discrete-time system. Finally, some simulation results showed the effectiveness of the proposed methods

Robotic device for the inspection of steel bridge structures

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (p. 83-84).The aging of America's steel bridges presents many challenges. Undetected cracks and corrosion can eventually lead to catastrophic failure. Due to the difficulties with inspecting existing bridges the use of mobile robots for steel bridge inspection has become an important area of research. This thesis describes the analysis, design, and implementation of a new approach to steel bridge inspection robots using tilting feet equipped with permanent magnets. This robot, titled "Mag-Feet", is capable of adhering to steel surfaces and can move along steel surfaces using a combination of three distinct gait modes. These three gait modes allow the robot to "Moonwalk" along horizontal surfaces, "Shuffle" up inclined surfaces, and "Swing" over small obstacles. The "Swing" motions present their own set of interesting challenges. Since the robot can only adhere to the surface using finite (and relatively small) magnetic forces, it may fall due to the reaction forces caused by the swing- up motion. To prevent failure modes, an optimal swing-up trajectory was designed so that the maximum reaction force during the trajectory was minimized. The trajectories were parameterized using sigmoids and were determined by solving the dynamic equations as a 2 point boundary value problem. Finally, a proof of concept prototype was constructed and was used to experimentally evaluate the design. These experiments illustrate the promise of the design and control approaches that were formulated.by Anirban Mazumdar.S.M