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We provide a method for planning under uncertainty for robotic manipulation by partitioning the configuration space into a set of regions that are closed under compliant motions. These regions can be treated as states in a partially observable Markov decision process (POMDP), which can be solved to yield optimal control policies under uncertainty. We demonstrate the approach on simple grasping problems,...
In this paper, the dynamic model of a robot with antagonistic actuated joints is presented, and the problem of full linearization via static state feedback is analyzed. The use of transmission elements with nonlinear relation between the displacement and the actuated force allows to control both the position and the stiffness of each joint. The main advantage of this actuation modality is that the...
A first step towards truly versatile robot assistants consists of building up experience with simple tasks such as the cooperative manipulation of objects. This paper extends the state-of-the-art by developing an assistant which actively cooperates during the point-to-point transportation of an object. Besides using admittance control to react to interaction forces generated by its operator, the robot...
A wheelchair-mounted robotic arm (WMRA) system was designed and built to meet the needs of mobility-impaired persons with limitations of upper extremities, and to exceed the capabilities of current devices of this type. The control of this 9-DoF system combines the 7-DoF robotic arm control with the 2-DoF power wheelchair control. The 3-degrees of redundancy can be optimized to effectively perform...
In this paper, based on a passivity framework, admittance-type and hybrid-type delay-compensated communication channel models are introduced, which warrant different bilateral control architectures for wave-based teleoperation under time delay. We utilize wave transforms and signal filtering for passivating the delayed-communication channel and passivity/stability conditions are derived using scattering...
NASA's future lunar and martian missions will require a suite of advanced robotic systems to complete tasks during precursor visits and to assist humans while present on the surface. The Centaur is a new mobile, dexterous manipulation system designed with this future role in mind. Centaur combines the sophisticated upper body dexterity of NASA's humanoid, Robonaut, with a rugged and versatile four-wheeled...
This paper reports work on the automation of a hot metal carrier, which is a 20 tonne forklift-type vehicle used to move molten metal in aluminium smelters. To achieve efficient vehicle operation, issues of autonomous navigation and materials handling must be addressed. We present our complete system and experiments demonstrating reliable operation. One of the most significant experiments was five-hours...
The least squares approach works efficiently in value function approximation, given appropriate basis functions. Because of its smoothness, the Gaussian kernel is a popular and useful choice as a basis function. However, it does not allow for discontinuity which typically arises in real-world reinforcement learning tasks. In this paper, we propose a new basis function based on geodesic Gaussian kernels,...
Prediction of dynamic features is an important task for determining the manipulation strategies of an object. This paper presents a technique for predicting dynamics of objects relative to the robot's motion from visual images. During the learning phase, the authors use recurrent neural network with parametric bias (RNNPB) to self-organize the dynamics of objects manipulated by the robot into the...
Fast detection of objects in a home or office environment is relevant for robotic service and assistance applications. In this work we present the automatic localization of a wide variety of differently shaped objects scanned with a laser range sensor from one view in a cluttered setting. The daily-life objects are modeled using approximated superquadrics, which can be obtained from showing the object...
This paper describes a new realtime collision avoidance algorithm for a robot manipulator based on a new visual servo control. In the proposed algorithm, it is not necessary to compute the 3D position of the obstacle. Further, the manipulator can avoid the fast moving obstacle. The developed system uses several small light-weight high-speed vision chips placed on the surface of the robot manipulator...
In this paper, an approach to interaction control of a robot manipulator with a partially known environment is proposed. The environment is a rigid object of known geometry but of unknown and possibly time-varying position and orientation. An algorithm for online estimation of the object pose is adopted, based on visual data provided by a camera as well as on forces and moments measured during the...
In the robotic-assisted off-pump coronary artery bypass graft (CABG) surgery, surgeon performs the operation with intelligent robotic instruments controlled through teleoperation that replace conventional surgical tools. The robotic tools actively cancel the relative motion between the surgical instruments and the point of interest on the beating heart. Measuring the motion of the heart during this...
Parallel manipulators might be severely damaged while crossing parallel singularities, because the actuator forces required to keep the platform on a given trajectory might approach infinity. It is thus important to know whether a desired pose of the platform in the workspace can be reached through a singularity-free path or not, and, in the first case, which path should be followed. This paper presents...
Growing new robotic applications in agriculture, food-processing, assisted surgery and haptics, which requires handling of highly deformable objects, present a number of design challenges; among these are methods to analyze deformable contacts. Recently, meshless methods (MLM), which inherit many advantages of finite element method (FEM) and yet need no explicit mesh structure to discretize geometry,...
This paper describes the design, construction and testing of an automated system for the assembly and packaging of triangular sandwiches. This process is currently highly labour intensive with little automated machinery available. This paper analyses the current manual production techniques and develops a number of modular workstations which can be incorporated into an existing line in place of human...
This paper describes a truss climbing robot we designed and prototyped. The robot has a minimalist design with three motive degrees of freedom that enable movement along three-dimensional truss structures. This robot can form a six-degree-of-freedom structure by connecting to another identical module using a passive bar as a medium. We present the design and implementation of this robot, control algorithms...
In this article, we propose a fast on-line closed loop identification method of continuous-time combined with an output feedback controller of the generalized proportional integral type (GPI), for the control of an uncertain flexible robotic arm with unknown mass at the tip, including a Coulomb friction term in the motor dynamics. A fast, non-asymptotic, algebraic identification method is used to...
New technologies and processes enhance the need for direct human-robot-interaction, to fully exploit the potential of robots' accuracy and humans' adaptability. Therefore, the hazardous potential of the involved robot manipulator needs to be minimised. Limits must be set, so that only an acceptable severity of injury for the human will remain in case of an unintended contact between the robot and...
In this paper, a new dynamic model for continuum robot manipulators is derived. The dynamic model is developed based on the geometric model of extensible continuum robot manipulators with no torsional effects. The development presented in this paper is an extension of the dynamic model proposed by Mochiyama and Suzuki (2002) to include a class of extensible continuum robot manipulators. Numerical...
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