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A position-based impedance controller has been implemented on a mini-excavator. Its performance and an approach to evaluate its stability robustness for given environment impedances are discussed. A dual hybrid teleoperation controller is proposed for machine control. Issues of transparency are discussed.
This paper describes the design, implementation and control of an enhanced container quay-crane. The new crane is based on a novel reeving arrangement which allows both fast and accurate gross motion as well as fine micropositioning. The paper describes the essential theory behind the mechanical design and the design of a controller that minimises load sway. The controller uses measurements of the...
This paper describes the design of a high integrity navigation system for use in large autonomous mobile vehicles. A frequency domain model of sensor contributions to navigation system performance is used to study the performance of a conventional navigation loop. On the basis of this, a new navigation system structure is introduced which is capable of detecting faults in any combination of navigation...
Draglines are extremely large machines that are widely used in open-cut coal mines for overburden stripping. Since 1994 we have been working toward the development of a computer control system capable of automatically driving a dragline for a large portion of its operating cycle. This has necessitated the development and experimental evaluation of sensor systems, machines models, closed-loop control...
Maneuvers of a nonholonomic vehicle in a structured dynamic environment are considered. The paper focuses on motion generation and control methods to autonomously perform lane following/changing and parallel parking maneuvers. Lane following/changing involves the tracking of a nominal trajectory in the traffic lane, and the generation and tracking of local lane-changing trajectories, for instance,...
Sensor-based dynamic path modification is one of powerful issues to combine planning and reactive control. This paper treats problems related to flexible trajectories implementation and presents solutions to connect functional levels from the planning to the execution. A general dynamic path structure is proposed and discussed including execution needs and constraints. Implementation algorithms are...
This paper adresses the problem of parametrizing with respect to time a feasible path for a mobile robot towing a trailer. We propose a robust approach, deriving from previous works on minimum time parametrization of a path for a manipulator. Numerical integrations of differential equations are replaced by piece-wise defined continuous functions. Our approach has been validated by experiments.
This paper describes experiments with an electrically actuated one legged hopping robot, the ARL Monopod. While a spring-mass system, comprised of the leg spring and the body mass has previously provided the basic “passive dynamic” vertical motion, we have now added a spring in series with the hip actuator to use the same passive dynamic principle for the leg swing motion. This paper validates our...
ROBICEN is a family of three pneumatic wall-climbing robots designed for inspection of nuclear power plants. In particular, ROBICEN III is a very lightweight robot of only 2.5 Kg, capable of travelling at speeds of 0.3 m/s on flat walls and along large diameter cylindrical pipes. Its locomotive system is based on four compact suction cups, two fixed and two mobile, that allow the robot to move forward,...
The project of an eight legged robot for pipe inspections is presented. The mechanical design, the functional principle and the control concept are described. The latter includes the task distribution to the hierarchically organized controller levels and the methods used for the control of the leg forces and robot motion.
The paper describes the possibilities of enhancing the performance of autonomous vehicles by interacting with the surrounding environment. Benefits and drawbacks of the use of different sensors and strategies for integrating the acquired knowledge are examined in an example case of a ‘through partly closed door’ navigation task for an AGV. This illustrates the increased ability of sensors to acquire...
This paper presents the experimental aspects of a robotic system used for detection, sorting and grading of paper objects from visual features. The experimental system is used as an automated paper recycling system. The system uses simplified stereo vision to compute position estimate of unknown objects. A vector of geometrical and textural features is used for sorting the paper, according to its...
In this paper, a new algorithm is described for dynamic map building with geometrical primitives for a mobile robot. The dynamic map is built up using a 2D range finder mounted on the mobile robot LiAS1 which is navigating in the environment. The dynamic map is used for both planning and localisation purposes. The map is composed of line segments and circles. For the extraction of line segments, a...
This paper summarizes a new approach for mobile robot localization based upon data from an onboard multi sensor system. Initialization of the robot posture as well as recursive in-motion posture estimation is considered. Accuracy, robustness, and long term stability of the proposed approach is demonstrated by means of long range experiments with path lengths of more than one kilometer and robot velocities...
This paper deals with the Manipulation Subsystem of the i.ARES Project demonstration vehicle (rover) designed for moon exploration purposes. The subsystem is a very light robotics structure with six degrees of freedom and a sensorized gripper (vision & force sensors). It includes the control electronics hardware and the software required for autonomous functions and for on-ground teleguiding.
In this paper a new method of modeling nonlinear friction as a function of both position and velocity is introduced. The proposed empirical model uses spectral analysis to identify the main sources of position dependent friction in complex mechanisms. In addition, the model describes the contribution to the overall friction of every moving part of the mechanism. In the paper, the proposed spectral-based...
The manipulator described in this paper is a novel three degree-of-freedom device that is ideally suited as a robotic wrist or platform manipulator. Because of its similarity to the human wrist, the invention has been named the “Carpal Wrist.’ Much like its natural counterpart, the Carpal Wrist has eight primary links, corresponding to the eight carpal bones of the human wrist, a parallel actuation...
We present preliminary results of the design of a mini inparallel 3-d.o.f. positioning system called MIPS. MIPS degrees of freedom are one translation and two orientations, which are obtained by the motions of linear magnetic actuators acting within a special in-parallel mechanical architecture. Its overall width will be about 1cm for a length of about 3cm. MIPS should be useful in medical applications...
A seven axis haptic device, called the Freedom-7, is described in relation to its application to surgical training. The generality of its concept makes it also relevant to most other haptic applications. The design rationale is driven by a long list of requirements since such a device is meant to interact with the human hand: uniform response, balanced inertial properties, static balancing, low inertia,...
This paper describes the analysis of actual micro-surgery operation to determine the specifications of a tele-micro-surgery system. The implemented system for the connection of micro blood vessels consists of multiple micro co-located operation point slave manipulators, macro rotational-force-feedback-free master manipulators and a vision system which is comprised of a fixed viewpoint microscope and...
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