This paper deals with a continuous design task of a planar cable robot used in a gait training machine called the cable-driven legs trainer. The design of cable robots requires satisfying two constraints, that is, tensions in the cables must remain non-negative, and cable interferences should be avoided. The carried design approach is based on interval analysis, which is one of the most efficient methods to obtain certified results. The constraints of non-negative tensions and cable to end-effector interference are solved using interval analysis tools. By means of a dynamic simulation, the reached workspace and the produced wrenches of the cable robot are evaluated as a set of interval vectors. An optimization algorithm is then designed to optimize the cable robot structure for the gait training machine. The robot is designed to produce non-negative tensions in the cables and to avoid collision at all times within the desired workspace and under the required external loads.

In this paper, a multi-objective design optimization of the 3-UPU translational parallel manipulator is presented. Based on a new algorithm, which combines the genetic algorithms and the Krawczyk operator, the robot position error is minimized and the robot design parameters tolerances are maximized, simultaneously. The results show that the designer can maintain the manipulator accuracy by using a specific size of the base, and can restrict its tolerance even by enlarging the actuators’ tolerance intervals. This algorithm is also used to determine the maximum design parameters tolerances for an allowable robot position error. The proposed algorithm can be extended to optimize other types of robots.

This paper proposes an interval-based approach in order to obtain the obstacle-free workspace of parallel mechanisms containing one prismatic actuated joint per limb, which connects the base to the end-effector. This approach is represented through two cases studies, namely a 3-RPR planar parallel mechanism and the so-called 6-DOF Gough–Stewart platform. Three main features of the obstacle-free workspace are taken into account: mechanical stroke of actuators, collision between limbs and obstacles and limb interference. In this paper, a circle(planar case)/spherical(spatial case) shaped obstacle is considered and its mechanical interference with limbs and edges of the end-effector is analyzed. It should be noted that considering a circle/spherical shape would not degrade the generality of the problem, since any kind of obstacle could be replaced by its circumscribed circle/sphere. Two illustrative examples are given to highlight the contributions of the paper.

This paper proposes a systematic algorithm based on the concept of interval analysis to obtain the maximal singularity-free circle or sphere within the workspace of parallel mechanisms. As case studies the 3-RPR planar and 6-UPS parallel mechanisms are considered to illustrate the relevance of the algorithm for 2D and 3D workspaces. To this end, the main algorithm is divided into four sub-algorithms, which eases the understanding of the main approach and leads to a more effective and robust algorithm to solve the problem. The first step is introduced to obtain the constant-orientation workspace and then the singularity locus. The main purpose is to obtain the maximal singularity-free workspace for an initial guess. Eventually, the general maximal singularity-free workspace is obtained. The main contribution of the paper is the proposition of a systematic algorithm to obtain the maximal singularity-free circle/sphere in the workspace of parallel mechanisms. The combination of a maximal singularity-free circle or sphere with the workspace analysis by taking into account the stroke of actuators, as additional constraint to the latter problem, is considered. Moreover, the center point of the circle/sphere is not restrained to a prescribed point.

AIS was primarily developed to exchange vessel-related data among vessels or AIS stations by using very-high frequency (VHF) technology to increase safety at sea. This study evaluates the formal integrity, availability, and the reporting intervals of AIS data with a focus on vessel movement prediction. In contrast to former studies, this study is based on a large data collection of over 85 million AIS messages, which were continuously received within a time period of two months. Thus, the evaluated data represent a comprehensive and up-to-date view of the current usage of AIS systems installed on vessels. Results of previous studies concerning the availability of AIS data are confirmed and extended. New aspects such as reporting intervals are additionally evaluated. Received messages are stored in a database, which allows for performing database queries to evaluate the obtained data in an automatic way. This study shows that almost ten years after becoming mandatory for professional operating vessels, AIS still lacks availability for both static and dynamic data and that the reporting intervals are not as reliable as specified within the technical AIS standard.

This paper reports on the potential application of interval Kalman filtering techniques in the design of a navigation system for an uninhabited surface vehicle named Springer. The interval Kalman filter (IKF) is investigated for this task since it has had limited exposure for such usage. A state-space model of the Springer steering dynamics is used to provide a framework for the application of the Kalman filter (KF) and IKF algorithms for estimating the heading angle of the vessel under erroneous modelling assumptions. Simulations reveal several characteristics of the IKF, which are then discussed, and a review of the work undertaken to date presented and explained in the light of these characteristics, with suggestions on potential future improvements.

Miniaturized surgical devices are promising for the future development of minimally invasive and endoluminal surgery. However, the dexterity and therapeutic functions of these devices are limited. In this paper, a reconfigurable modular robotic system is proposed to perform screening and interventions in the gastrointestinal tract. In the proposed system, millimeter-sized robotic modules are ingested and tasked to assemble into an articulated mechanism in the stomach cavity. The modules are assembled according to the target location to perform precise intervention. Based on this concept, a preliminary report is presented covering the robotic schemes for the endoluminal reconfigurable platform, the design with structural functions, the control strategy, and the interval-based constraint satisfaction algorithm to determine the suitable topologies of the reconfigurable robot for the given task.

This study focuses on the analysis of temporal patterns in the spike train of cells in the lateral geniculate nucleus (LGN) of cat. Two-hundred eighty-three units have been recorded extracellularly in anesthetized animals during visual stimulation with flashing spot stimuli of different size. We used a novel method of temporally local computed interval distributions (intervalogram; Funke & Wörgötter, 1995) to visualize the statistical distribution of interspike intervals during different phases of the visual response. Multimodal interval distributions were observed mainly in X- and Y-ON cells, reflecting the tendency of these cells to fire with preferred intervals during the sustained light response. The shortest preferred interval is called the fundamental interval and the longer ones (higher-order intervals) are, in general, multiples thereof. During increasing surround inhibition a redistribution of the intervals towards the higher orders was observed. We regarded the different peaks in the interval distributions as different components of possible temporal spike sequences and performed a pattern search up to the level of five subsequent intervals. While it is obvious, that the dominant peak is most strongly represented in any interval sequence, we also show that a significant overrepresentation of short sequences of similar intervals exists. The repetition rate is rather small (4–5 intervals) and, therefore, no long-lasting oscillatory pattern was observed in the autocorrelograms. Power spectral analysis of the peristimulus-time histograms, however, revealed that the sequential firing pattern is strongly stimulus locked at least for the majority of sweeps in the records.

The mean firing rate of an LGN cell decreases with increasing stimulus size as well as with decreasing contrast. Therefore, the mean rate cannot be used to distinguish between these situations. While in the whole network this tradeoff can be resolved by the combined activity of multiple cells, our findings additionally suggest that contrast and size can be distinguished already at the single-cell level using different temporal patterns.

A general framework for computing robust controllable sets ofconstrained nonlinear uncertain discrete-time systems as well ascontrolling such complex systems based on the computed robustcontrollable sets is introduced in this paper. The addressedone-step control approach turns out to be a robust model predictivecontrol scheme with feasible unit control horizon and contractiveconstraint. The solver of 1-dimensional quantified set inversion inmodal interval analysis is extended to 2-dimensional cases forcomputing robust controllable sets off-line with a clear semanticinterpretation, where both universal and existential quantifiers areconcerned simultaneously. An interval-based solver of constrainedminimax optimization is also proposed to compute one-step controlinputs online in a reliable way, which guarantee to drive the systemstate contractively along the computed robust controllable sets to aselected terminal robust control invariant set.

The purpose of this article is to show the great interest of theuse of propagation (or pruning) techniques, inside classicalinterval Branch-and-Bound algorithms. Therefore, a propagationtechnique based on the construction of the calculus tree isentirely explained and some properties are presented without theneed of any formalism (excepted interval analysis). This approachis then validated on a real example: the optimal design of anelectrical rotating machine.