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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...
Automated target acquisition and docking is key to enabling various applications of autonomous mobile robots in indoor environments. For the purpose, many researches have been devoted to the development of location sensing techniques employing the latest in RFID or GPS. However, it has not yet become possible to attain high accuracy in those techniques, particularly in cluttered or dynamically changing...
This work deals with the problem of force/position trajectory tracking under uncertainties arising from surface position and orientation. A robotic finger with a soft hemispherical tip of uncertain compliance parameter is considered in contact with a rigid flat surface. A novel adaptive controller is designed using online estimates of the unknown parameters and is proved to achieve force and position...
In this paper, a control scheme that combines trajectory planning and gaze direction control for robotic exploration is presented. The objective is to calculate the gaze direction and simultaneously plan the trajectory of the robot over a given time horizon, so that localization and map estimation errors are minimized while the unknown environment is explored. Most existing approaches perform a greedy...
For implementing dynamic target tracking, two distributed CCD (charge-coupled device) cameras are set up to capture the poses of the tracking and target cars, which have the front-wheel for the steering orientation and the rear-wheel for the forward-backward motion. Based on the control authority of these two CCD cameras, a suitable reference command for the proposed controller of the tracking car...
Autonomous navigation for wheeled mobile robots generally requires to plan a trajectory and to follow it while performing localization in the environment. In order to execute long-range motion, dead-reckoning localization is not precise enough and the robot must use landmark-based localization. Landmark-based localization can produce discontinuities in the robot position estimation, as it is well...
We discuss a ZMP-based running pattern generation for a biped robot equipped with toe springs. Our biped robot HRP-2LT has twelve active DoFs for its legs and two passive DoFs for its toes. The trajectory of the center of mass is designed to realize the specified running motion and the foot trajectories are determined to get proper spring action at lift off phases. They are interpreted into joint...
Skid-steered mobile robots have been widely used for terrain exploration and navigation. In this paper, we present an adaptive trajectory control design for a skid-steered wheeled mobile robot. Kinematic and dynamic modeling of the robot is first presented. A pseudo-static friction model is used to capture the interaction between the wheels and the ground. An adaptive control algorithm is designed...
This paper presents a technique to improve the data association in the iterative closest point based scan matching. The method is based on a distance-filter constructed on the basis of an analysis of the set of solutions produced by the associations in the sensor configuration space. This leads to a robust strategy to filter all the associations that do not explain the principal motion of the scan...
Human machine collaborative systems (HMCS) have been developed to enhance sensation and suppress extraneous motions or forces during surgical tasks requiring precise motion. However, to date such systems have enforced constraints on the position or path of a tool, but have not considered the dynamics of motion. Also, the focus has been on the effect of guidance of motion during a task, rather than...
Crawler mechanisms have the advantage of stable navigation on uneven terrain; as a result, such mechanisms have been adopted for many types of locomotion of outdoor robots, including "search and rescue robots". However, crawler mechanisms always slip when tracking curved paths, and it generates a large accumulating positioning error in vehicles as opposed to conventional wheeled mobile robots...
In this paper, we present a vision-based terrain mapping and analysis system, and a model predictive control (MPC)-based flight control system, for autonomous landing of a helicopter-based unmanned aerial vehicle (UAV) in unknown terrain. The vision system is centered around Geyer et al.'s recursive multi-frame planar parallax algorithm (2006), which accurately estimates 3D structure using geo-referenced...
An indirect iterative learning algorithm has shown to be able to update the parameters of an acceleration feedback controller for flexible manipulators. The fine estimation of the masses of a chain of mass-spring-dampers units allows the simultaneous tuning of both the feedback controller and the trajectory generation. This algorithm has been validated on an industrial robot arm.
We describe the design, fabrication, and testing of an ultra-low cost orthotweezers system for microassembly. By utilizing rapid prototyping technology, compliant mechanisms, and commodity-grade actuators and sensors, we significantly reduce the complexity and cost of the previous Orthotweezers system without sacrificing functionality. With a force resolution of 0.7mN and a worst case mean positioning...
This paper presents a task instruction scheme for a service robot operating in a daily life environment. It is difficult for the robot to execute tasks automatically in the daily life environment, because it should handle various objects and the working environment is complex. In such an environment, the concept of shared autonomy by which the robot can share a task with a human is important. 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...
This paper relates recent advances in the design of feedback laws for the 3D movement of an Eel-like robot. Such a robot is under construction in the context of a national French robotic project. The proposed feedback enables the tracking of a desired 3D position of the Eel head as well as the stabilization of the rolling angle. A velocity controller is also proposed. The controller is tested on a...
In this paper, two experimental case studies performed with a multi-robot system made of 6 Khepera II mobile robots are presented. The experiments, performed at the laboratory LAI (Laboratorio di Automazione Industriale) of the Universita degli Studi di Cassino, are aimed at testing the performances and the robustness of a behavior-based technique, namely the null-space-based behavioral control (NSB),...
Path planning for formations of wheeled mobile robots (WMRs) has been an active research topic of robotics in the recent years. The methods of route generation for WMRs usually utilize complex algorithms, which require global information of the workspace or mapping of the nearby environment. Hence they are not very efficient for formation based motion of large collections of small entry-level agents...
This paper presents a simple stabilizing control scheme for the rolling sphere. A tracking control problem with respect to a "virtual moving trajectory" is first solved. Then, it is used to achieve practical stability for the regulation problem. The derived controllers have a simple form and can guarantee fast convergence. To verify the effectiveness of the proposed results, an interesting...
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