Search results for "Artificial intelligence"
showing 10 items of 6122 documents
Static and Dynamic Objects Analysis as a 3D Vector Field
2017
International audience; In the context of scene modelling, understanding, and landmark-based robot navigation, the knowledge of static scene parts and moving objects with their motion behaviours plays a vital role. We present a complete framework to detect and extract the moving objects to reconstruct a high quality static map. For a moving 3D camera setup, we propose a novel 3D Flow Field Analysis approach which accurately detects the moving objects using only 3D point cloud information. Further, we introduce a Sparse Flow Clustering approach to effectively and robustly group the motion flow vectors. Experiments show that the proposed Flow Field Analysis algorithm and Sparse Flow Clusterin…
Homography based egomotion estimation with a common direction
2017
International audience; In this paper, we explore the different minimal solutions for egomotion estimation of a camera based on homography knowing the gravity vector between calibrated images. These solutions depend on the prior knowledge about the reference plane used by the homography. We then demonstrate that the number of matched points can vary from two to three and that a direct closed-form solution or a Gröbner basis based solution can be derived according to this plane. Many experimental results on synthetic and real sequences in indoor and outdoor environments show the efficiency and the robustness of our approach compared to standard methods.
Robust adaptive tracking control of uncertain systems with time-varying input delays
2017
ABSTRACTIn this paper, the problem of robust adaptive tracking control of uncertain systems with time-varying input delays is studied. Under some mild assumptions, a robust adaptive controller is designed by using adaptive backstepping technique such that the system is globally stable and the system output can track a given reference signal. At the same time, a root mean square type of bound is obtained for the tracking error as a function of design parameters and thus can be adjusted. Finally, one numerical example is given to show the effectiveness of the proposed scheme.
Adaptive Control of Soft Robots Based on an Enhanced 3D Augmented Rigid Robot Matching
2021
Despite having proven successful in generating precise motions under dynamic conditions in highly deformable soft-bodied robots, model based techniques are also prone to robustness issues connected to the intrinsic uncertain nature of the dynamics of these systems. This letter aims at tackling this challenge, by extending the augmented rigid robot formulation to a stable representation of three dimensional motions of soft robots, under Piecewise Constant Curvature hypothesis. In turn, the equivalence between soft-bodied and rigid robots permits to derive effective adaptive controllers for soft-bodied robots, achieving perfect posture regulation under considerable errors in the knowledge of …
Dynamic Modeling of Planar Multi-Link Flexible Manipulators
2021
A closed-form dynamic model of the planar multi-link flexible manipulator is presented. The assumed modes method is used with the Lagrangian formulation to obtain the dynamic equations of motion. Explicit equations of motion are derived for a three-link case assuming two modes of vibration for each link. The eigenvalue problem associated with the mass boundary conditions, which changes with the robot configuration and payload, is discussed. The time-domain simulation results and frequency-domain analysis of the dynamic model are presented to show the validity of the theoretical derivation.
Dynamic Modeling, Energy Analysis, and Path Planning of Spherical Robots on Uneven Terrains
2020
Spherical robots are generally comprised of a spherical shell and an internal actuation unit. These robots have a variety of applications ranging from search and rescue to agriculture. Although one of the main advantages of spherical robots is their capability to operate on uneven surfaces, energy analysis and path planning of such systems have been studied only for flat terrains. This work introduces a novel approach to evaluate the dynamic equations, energy consumption, and separation analysis of these robots rolling on uneven terrains. The presented dynamics modeling, separation analysis, and energy analysis allow us to implement path planning algorithms to find an optimal path. One of t…
An Input Observer-Based Stiffness Estimation Approach for Flexible Robot Joints
2020
This letter addresses the stiffness estimation problem for flexible robot joints, driven by variable stiffness actuators in antagonistic setups. Due to the difficulties of achieving consistent production of these actuators and the time-varying nature of their internal flexible elements, which are subject to plastic deformation over time, it is currently a challenge to precisely determine the total flexibility torque applied to a robot's joint and the corresponding joint stiffness. Herein, by considering the flexibility torque acting on each motor as an unknown signal and building upon Unknown Input Observer theory, a solution for electrically-driven actuators is proposed, which consists of …
Using the Analytic Hierarchy Process (AHP) in Evaluating the Decision of Moving to a Manufacturing Process Based Upon Continuous 5 Axes CNC Machine-t…
2016
Abstract This paper represents the second part of the work described in the paper with the title “Decision-making tool for moving from 3-axes to 5-axes CNC machine-tool”. The problem of using either 3 axes CNC machine-tools or 5 axes CNC machine tools was presented in the first part, together with a fuzzy logic based decision support tool. This time, an AHP approach is used in order to evaluate the decision of moving to a manufacturing process based upon 5 axes machine tools. Three variants were taken into consideration and analysed. The consistency of the proposed approach was evaluated and a sensitivity analysis was also introduced.
Assembly Assistance System with Decision Trees and Ensemble Learning
2021
This paper presents different prediction methods based on decision tree and ensemble learning to suggest possible next assembly steps. The predictor is designed to be a component of a sensor-based assembly assistance system whose goal is to provide support via adaptive instructions, considering the assembly progress and, in the future, the estimation of user emotions during training. The assembly assistance station supports inexperienced manufacturing workers, but it can be useful in assisting experienced workers, too. The proposed predictors are evaluated on the data collected in experiments involving both trainees and manufacturing workers, as well as on a mixed dataset, and are compared …
Propulsion monitoring system for digitized ship management: Preliminary results from a case study
2020
Abstract The paradigm of Industry 4.0 a fundamental driver of innovation in marine industry, where the new digital era will see the development of smart cyber-ships equipped with advanced automation systems that will progressively evolve towards fully autonomous vessels. Although the journey towards such technological frontier has started, most companies operating in the maritime sector still appear un-prepared to face the future scenario. In the maritime sector, in fact, empirical models and oversimplified approaches are still largely employed for the management of fleet operations. There is thus the necessity of developing and providing operative models for digitized ship management, whic…