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In the present work, the modeling of a rigid-flexible two link robot via the Euler-Lagrange formalism, is outlined. The flexible-link is considered to be an Euler-Bernoulli beam with a mass attached at its free end simulating a payload. Two control schemes which are known to yield acceptable results for single flexible-link robots are extended and applied to achieve regulation for the joints of the...
Hitting and batting tasks, such as tennis forehands, ping-pong strokes, or baseball batting, depend on predictions where the ball can be intercepted and how it can properly be returned to the opponent. These predictions get more accurate over time, hence the behaviors need to be continuously modified. As a result, movement templates with a learned global shape need to be adapted during the execution...
In this paper, we develop an asymmetric s-curve profile method with jerk bounded to obtain high-precision motion and reduce the residual vibration. All possible instances for asymmetric s-curve profile planning are analyzed. The algorithm and its implementation are proposed with a direct and complete method. Simulation results are presented to verify the effectiveness and reliability of the proposed...
Dynamic movement primitives (DMPs) have been proposed as a powerful, robust and adaptive tool for planning robot trajectories based on demonstrated example movements. Adaptation of DMPs to new task requirements becomes difficult when demonstrated trajectories are only available in joint space, because their parameters do not in general correspond to variables meaningful for the task. This problem...
This work describes the controlling of a physical platform and the mathematical model for a single link flexible robot manipulator, whose motion is restricted to an horizontal plane, so that the gravity effects are neglected. The modeling problem is addressed from so-called Euler-Bernoulli beam equation. The design, construction and integration of an experimental set-up developed for this work is...
In this paper, a novel 3-D motion trajectory signature is introduced to serve as an effective description to the raw trajectory. More importantly, based on the trajectory signature, a probabilistic model-based cluster signature is further developed for modeling a motion class. The cluster signature is a mixture model-based motion description that is useful for motion class perception, recognition...
Much like a falling cat can reorient itself to land on its feet, a climbing robot should also reorient itself to minimize damage during a fall. This paper presents and analyzes the dynamic motion of a modular robot, called CKbot righting itself during a fall. It presents a mathematical model of the falling system that correlates well with experimental reorientation results about one axis. The model...
A soft, mobile, morphing robot is a desirable platform for traversing rough terrain and navigating into small holes. In this work, a new paradigm in soft robots is presented that utilizes jamming of a granular medium. The concept of activators (as opposed to actuators) is presented to jam and unjam cells that then modulate the direction and amount of work done by a single central actuator. A prototype...
In this study, grasp positions of human hands are measured for planar objects for development of a reasonable grasp criterion for a two-soft-fingered robotic hand. We first propose a grasp criterion that yields the best grasping position for a robot hand with two soft fingers. To examine the properties of this criterion with respect to some weighting coefficients included in the criterion, a grasping...
Shape memory alloy (SMA) composites offer a great potential as actuators because of its excellent power to weight ratio, smooth motion and silent actuation. However, SMA actuated robotic manipulator systems have severe hysteresis, system nonlinearities, model and parametric uncertainties those are often responsible for position inaccuracy in a regulation or tracking system. A simple and upstanding...
The inherent uncertainty associated with unstructured grasping tasks makes establishing a successful grasp difficult. Traditional approaches to this problem involve hands that are complex, fragile, require elaborate sensor suites, and are difficult to control. Alternatively, by carefully designing the mechanical structure of the hand to appropriately incorporate features such as compliance and adaptability,...
In this paper, three-dimensional caging by a multifingered hand (3D multifingered caging) is studied. Caging is a method of object constraining in which robot bodies surround an object and make it inescapable from the ldquocagerdquo composed of the robot bodies. In 3D multifingered caging, position-controlled robot hands can constrain objects and transport them, and force control is not necessary...
This paper presents a method to predict a fish motion by neural network (N.N.) with on-line learning when a robot is pursuing fish-catching by a net at hand through hand-eye robot visual servoing. We have learned by previous experiments that fish is much smarter than a robot controlled by visual servoing whose escaping strategy is to make a steady state distance error between the net at robotpsilas...
In this paper, the purpose is to realize self-propelling ability of a snake like robot which travels in pipes. The robot consists of thirteen intelligent actuators and each actuator has a DC motor and a micro processor including a motor driver and communication function. Three control algorithms, force control, adjusting controls to changing pipe diameter and to curved pipe are proposed and programmed...
This paper presents a trajectory planning strategy of a wheeled mobile robot in an obstructed environment. In order to sense its surrounding environment, the mobile robot is assumed to be equipped with a laser range finder. The potential field method is utilized to create force fields around obstacles and a goal. Look-ahead control is adopted to steer the mobile robot in which a reference point located...
This article presents a synchronization control strategy, which can be applied to formation control of swarm of robots. A decentralized trajectory tracking controller is developed with feedback of both position and synchronization errors, formed with a combination of feedforward and feedback controls. It is proven that this tracking controller can asymptotically converge both position and synchronization...
The atomic force microscope (AFM) has been widely used as a nano-effector with a function of force sensing to detect interaction forces between an AFM tip and a sample, thereby controlling the process of the nanomanipulation. However, both the extent and accuracy of force application are significantly limited by the nonlinearity of the commonly used optical lever with a nonlinear position-sensitive...
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