116 research outputs found
Experimental External Force Estimation Using a Non-Linear Observer for 6 axes Flexible-Joint Industrial Manipulators
This paper proposes a non-linear observer to estimate not only the state (position and velocity) of links but also the external forces exerted by the robot during Friction Stir Welding (FSW) processes. The difficulty of performing this process with a robot lies in its lack of rigidity. In order to ensure a better tracking performance, the data such as real positions, velocities of links and external forces are required. However, those variations are not always measured in most industrial robots. Therefore, in this study, an observer is proposed to reconstruct those necessary parameters by using only measurements of motor side. The proposed observer is carried out on a 6 DOF flexible-joint industrial manipulator used in a FSW process.ANR-2010-SEGI-003-01-COROUSSO, French National Agenc
CCD UBV photometric and Gaia astrometric study of eight open clusters- ASCC 115, Collinder 421, NGC 6793, NGC 7031, NGC 7039, NGC 7086, Roslund 1 and Stock 21
In this study, we carried out CCD UBV photometry of eight open clusters, ASCC
115, Collinder 421, NGC 6793, NGC 7031, NGC 7039, NGC 7086, Roslund 1, Stock
21, and determined their reddening, metallicity, distance, age, and mass
functions. We used new Gaia Data Release 2 (DR2) astrometric data to separate
cluster member stars from the field stars and obtain precise structural and
astrophysical parameters. To identify cluster member stars we utilized an
unsupervised membership assignment code (UPMASK), which is based on the
photometric and astrometric data. The density distributions for the open
clusters show good fits with the empirical King model except for Roslund 1 and
Stock 21 not having central concentration. The colour excesses and
metallicities were derived separately using U-B vs B-V two-colour diagrams.
Keeping these parameters as constants, we simultaneously calculated distance
moduli and ages of the clusters from V vs B-V and V vs U-B colour-magnitude
diagrams using PARSEC theoretical isochrones. Taking into account Gaia DR2
proper motion components and parallaxes of the member stars, we also calculated
mean proper motions and distances for the clusters. Distances derived both from
isochrone fitting to colour-magnitude diagrams of the clusters and Gaia DR2
trigonometric parallaxes are compatible with each other. Slopes of the mass
functions of the eight open clusters are in good agreement with Salpeter (1955)
value of 1.35.Comment: 24 pages, 12 figures and 7 tables, accepted for publication in
Astrophysics and Space Scienc
Limit states of steel supporting structure for bridge cranes
This paper describes a question of evaluation necessity of bridge cranes using the method of limit deformation state and oscillation damping. The solution was performed by means of theoretical analysis and an experimental verification at the selected bridge crane. The final result sounds that in the case of a correct strength computing of given bridge crane, it is not necessary to also check deformation and damping of oscillation as well.Web of Science10815814
Influence of frictions on gait optimization of a biped robot with an anthropomorphic knee
This paper presents the energy consumption of a biped robot with a new modelled structure of knees which is called rolling knee (RK). The dynamic model, the actuators and the friction coefficients of the gear box are known. The optimal energy consumption can also be calculated. The first part of the paper is to validate the new kinematic knee on a biped robot by comparing the energy consumption during a walking step of the identical biped but with revolute joint knees. The cyclic gait is given by a succession of Single Support Phase (SSP) followed by an impact. The gait trajectories are parameterized by cubic spline functions. The energetic criterion is minimized through optimization while using the simplex algorithm and Lagrange penalty functions to meet the constraints of stability and deflection of the mobile foot. An analysis of the friction coefficients is done by simulation to compare the human characteristics to the robot with RK. The simulation results show an energy consumption reduction through the biped with rolling knee configuration. The influence of friction coefficients shows the energy consumption of biped robot is close to that of the human.ANR-09-SEGI-011-R2A2; French National Research Agenc
A Novel Approach for Simplification of Industrial Robot Dynamic Model Using Interval Method
This paper proposes a new approach to simplify the dynamic model of industrial robot by means of interval method. Due to strong nonlinearities, some components of robot dynamic model such as the inertia matrix and the vector of centrifugal, Coriolis and gravitational torques, are very complicated for real-time control of industrial robots. Thus, a simplification algorithm is presented in this study in order to reduce the computation time and memory occupation. More importantly, this simplification is suitable for arbitrary trajectories in whole robot workspace. Furthermore, the method devotes to finding negligible inertia parameters, which is useful for robot model identification. A simulation has been carried out on a test trajectory using a 6-DOF industrial robot model, and the results have shown good performance and effectiveness of this method.ANR COROUSS
A 6DOF virtual environment space docking operation with human supervision
In this work, we present a synchronous co-simulation of a 6DOF (six degree of freedom) ball and plate platform and its 3D computer model. The co-simulation in the virtual environment is intended to mimic the rendezvous between a cargo vehicle such as the Falcon 9 from SpaceX and the ISS (International Space Station). The visual feedback sensing of the position of the 6DOF platform is implemented using a Kinect RGB-D device. The human in the loop acts as supervisory control for initiating the docking mechanism. This paper delivers an adaptive fractional order control solution which is easily tunable, implementable and validated on a laboratory benchmark. The results indicate that fractional order control can tackle large variability in the system dynamics and deliver specified performance at all times
Energy Management for a User Interactive Smart Community: A Stackelberg Game Approach
This paper studies a three party energy management problem in a user
interactive smart community that consists of a large number of residential
units (RUs) with distributed energy resources (DERs), a shared facility
controller (SFC) and the main grid. A Stackelberg game is formulated to benefit
both the SFC and RUs, in terms of incurred cost and achieved utility
respectively, from their energy trading with each other and the grid. The
properties of the game are studied and it is shown that there exists a unique
Stackelberg equilibrium (SE). A novel algorithm is proposed that can be
implemented in a distributed fashion by both RUs and the SFC to reach the SE.
The convergence of the algorithm is also proven, and shown to always reach the
SE. Numerical examples are used to assess the properties and effectiveness of
the proposed scheme.Comment: 6 pages, 4 figure
- …