501 research outputs found
Extending 3-DoF Metrics to Model User Behaviour Similarity in 6-DoF Immersive Applications
No full textImmersive reality technologies, such as Virtual and Augmented Reality, have
ushered a new era of user-centric systems, in which every aspect of the
coding--delivery--rendering chain is tailored to the interaction of the users.
Understanding the actual interactivity and behaviour of the users is still an
open challenge and a key step to enabling such a user-centric system. Our main
goal is to extend the applicability of existing behavioural methodologies for
studying user navigation in the case of 6 Degree-of-Freedom (DoF).
Specifically, we first compare the navigation in 6-DoF with its 3-DoF
counterpart highlighting the main differences and novelties. Then, we define
new metrics aimed at better modelling behavioural similarities between users in
a 6-DoF system. We validate and test our solutions on real navigation paths of
users interacting with dynamic volumetric media in 6-DoF Virtual Reality
conditions. Our results show that metrics that consider both user position and
viewing direction better perform in detecting user similarity while navigating
in a 6-DoF system. Having easy-to-use but robust metrics that underpin multiple
tools and answer the question ``how do we detect if two users look at the same
content?" open the gate to new solutions for a user-centric system
Rendering 6-DOF Object-to-Object Interaction with 3-DOF Haptic Interfaces
No full textThree degree-of-freedom (3-DOF) tool-based haptic interfaces are widely used in virtual environment to train operators, and for virtual prototyping and design. In some special cases with higher requirement on haptic fidelity, the tool needs to be modeled as an object with real volume rather than a single point. However, such object -to-object interaction will inherently involve reaction torques, which per definition cannot be reali zed by 3-DOF haptic interfaces. As a result, undesired system behavior such as vibration or sudden repulsion would occur whenever reaction torque is involved. In this paper , we proposed a penalty-based algorithm to realize stable yet convincing object-to-object interaction with 3-DOF haptic interfaces. The major contribution of this work is the regulation of excessive directional combined stiffness when multiple contact points are considered in the calculation of force feedback. In contrast to other 3-DOF rendering methods, our approach can generate translational movement to resemble the dynamics of end -effector during torque-involved interaction, while keeps the system stable throughout the whole task. A virtual peg-in-hole task was conducted to evaluate the performance of the proposed algorithm. We used the geometrical constraints to calculate an ideal trajectory of the end-effector as a function of the peg’s orientation. The result shows that the end-effector’s trajectory resembled the ideal one as the virtual tool was rotated in the hole. We also showed that the regulated combined stiffness converged to a desired value so that the system stayed stable throughout the whole interactionBMDBioMechanical EngineeringMechanical, Maritime and Materials Engineerin
A New Take on Prosthetic Wrists: The Development of a 3 DoF, Hydraulically Powered Wrist Prosthesis
No full textBackground: While new prosthetic hands are developed to increase functionality and allow more complex movements, prosthetic wrists are researched less. Although there are wrists available, primarily featuring 1 degree of freedom (DoF), only a few prototype 3 DoF wrists are currently known. These 3 DoF wrists usually have sufficient range of motion (RoM), but they fail in delivering high torques while being lightweight and compact, which can increase chances of rejecting the prosthesis. Objectives: The purpose of this study is to design and evaluate a conceptual 3 DoF wrist that is capable of replicating the RoM of the human wrist while keeping the size and mass as low as possible. Furthermore, the wrist needs to be able to deliver more torque than existing 3 DoF wrists. Results: A functional 3 DoF prototype was created. The design is actively controllable using three motors and pumps but can also adapt to different surroundings if the motors are off. The prototype is capable of a total range of motion of 142° for exion/extension and 90° for ulnar/radial deviation and can provide estimated torques of 4.52 Nm and 7.29 Nm respectively. Pro-/supination was not measured, but can provide a theoretical RoM of 134° and torque of 8.9 Nm. The complete wrist has a length of 150 mm and a diameter of 50 mm at the thickest part, and a mass of 166 g (including fluid). Conclusion: A 3 DoF wrist that is theoretically able to provide more torques than previously researched wrists is successfully designed and tested. The available RoM approaches the required RoM, except for pro-/supination. Future research should primarily focus on measuring the front part of the wrist using higher pressure. The 3D printed pro-/supination part of the wrist should be further researched to improve RoM and remove leakage while pressurized.Biomedical Engineerin
Data:9-DOF Transtibial Artificial Leg
No full textThis dataset is in support of my following Research papers Preprint (Make sure you have read Caution) :1. Novel ß Transtibial Prosthetic 9-DoF Artificial Leg Adaptive Controller - Part I , https://doi.org/10.36227/techrxiv.19758517.v12. Novel ß Transtibial Prosthetic 9-DoF Artificial Leg Adaptive Controller - Part II,, https://doi.org/10.36227/techrxiv.19762762.v13. Novel-ß-Transtibial Prosthetic 9-DoF Artificial Leg Adaptive Controller - Part I, https://doi.org/10.36227/techrxiv.20372577.v14. Novel-ß-Transtibial Prosthetic 9-DoF Artificial Leg Adaptive Controller - Part II, , https://doi.org/10.36227/techrxiv.20813938.v1In these paper series, the author has revealed complete modelling and algorithm with simulation success, which can be copied and implemented by readers in designing prototype. ******************************************************************************************** CautionThough the uploaded data is true,designed for the real practical scenarios only, involving either human subjects or animals, these are neither been clinically tested nor have been practically tested on humans nor by any doctor or any medical or any review board. The author is not responsible if the algorithm is misunderstood or all this is copied without understanding or improperly implemented and mishappening due to it.The author is not responsible if the copied values cause mishappening.********************************************************************************************THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Compliant Manipulator Design method: Applied for designing a 4-DoF manipulator with a TTTR-motion
No full textCurrent multi-DoF compliant manipulators are still rarely implemented in the industry because their range of motion (ROM) is limited as their designs are heavy and bulky or obtained by a serial set of multiple stacked flexure systems, which limits their compactness. The goal of this article is to overcome these limitations by considering them as an integrated multi-DoF compliant joint, either serial or parallel, and setting up a new method the Compliant Manipulator Design (COMAD)-method and investigate its performance. This method will combine the "Type synthesis of legs"-technique to include parallel kinematic solutions for the desired motion pattern whereafter the complete compliant solution space is obtained using the FACT-method. The method is applied for designing a 4-DoF-manipulator with a TTTR-motion pattern resulting in four new concepts composed of compactly aggregated wire flexures. After the concept selection, a demonstrator is manufactured which excellently possesses four decoupled motions with a relatively large ROM. This can be seen as a new milestone for designing multi-DoF compliant manipulators as it permits a larger ROM and better stiffness capabilities than those obtained from conventional methods because all compliant topologies are deflecting in series due to the parallel kinematic couplings within the multi-DoF flexure systems
Isabelle/DOF: Design and Implementation
No full textThis is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record17th International Conference, SEFM 2019
Oslo, Norway, September 18–20, 2019DOF is a novel framework for defining ontologies and enforcing them during document development and evolution. A major goal of DOF is the integrated development of formal certification documents (e. g., for Common Criteria or CENELEC 50128) that require consistency across both formal and informal arguments. To support a consistent development of formal and informal parts of a document, we provide Isabelle/DOF, an implementation of DOF on top of the formal methods framework Isabelle/HOL. A particular emphasis is put on a deep integration into Isabelleâs IDE, which allows for smooth ontology development as well as immediate ontological feedback during the editing of a document. In this paper, we give an in-depth presentation of the design concepts of DOFâs Ontology Definition Language (ODL) and key aspects of the technology of its implementation. Isabelle/DOF is the first ontology language supporting machine-checked links between the formal and informal parts in an LCF-style interactive theorem proving environment. Sufficiently annotated, large documents can easily be developed collabo- ratively, while ensuring their consistency, and the impact of changes (in the formal and the semi-formal content) is tracked automatically.IRT SystemX, Paris-Saclay, Franc
Graphic analysis of the linear and angular momentum of a dynamically balanced 1-dof pantographic linkage
No full textThis article presents a graphical analysis method for the verification of the gravity force balance and shaking force and shaking moment balance of a 1-DoF pantographic linkage. First the joint velocities of the linkage are graphically found of which the procedure is well known. To obtain the linear and angular momentum graphically, the mass and inertia of each element are modeled with two equivalent masses about the center of mass of the element, resulting in a mass and inertia equivalent model with solely point masses. The velocities of these point masses are obtained and each velocity vector is multiplied with the respective mass value to obtain vectors that represent the linear momentum. For force balance it is shown that the sum of all linear momentum vectors form a polygon. Subsequently the linear momentum vectors with their moment arms are transferred into an angular momentum diagram which for moment balance shows to sum up to zero.Accepted Author ManuscriptMechatronic Systems Desig
Event-Triggered Adaptive Fault-Tolerant Synchronization Tracking Control for Multiple 6-DOF Fixed-Wing UAVs
No full textIn contrast with most existing results concerning unmanned aerial vehicles (UAVs) wherein two-degree or only attitude/longitudinal dynamics are considered, this article proposes an event-triggered cooperative synchronization fault-tolerant control (FTC) methodology for multiple fixed-wing UAVs whose dynamics are six-degree-of-freedom (DOF) with twelf-state-variables subject to actuator faults, modeling uncertainties, and external disturbances. More precisely, an event-triggering mechanism is devised to determine the time instants of updating control signals, which reduces the signal transmission burden, while saving on system resources. The Zeno phenomenon is excluded in the sense of guaranteeing that the time between two consecutive switchings is lower bounded by a positive constant. The actuator faults as well as the network induced errors are handled via the bound estimation approach and some well-defined smooth functions. By strict Lyapunov arguments, all closed-loop signals are proved to be semi-globally uniformly ultimately bounded (SGUUB) and the synchronization tracking errors of speed and attitude converge to a residual set around origin whose size can be made arbitrarily small through selecting appropriate design parameters.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Bart De Schutte
Fine Tuning of a Force Balanced 1-DoF Rotating Mechanism
No full textVibration in moving mechanisms and manipulators is almost always present due to manufacturing tolerances, assembly errors and non-uniform density of materials. Small errors in parameters such as mass and length may result in a non-balanced mechanism producing shaking forces. Normally a mechanism would be balanced using a trial and error method, which repeats the use of trial weights and measurements until the mechanism is balanced, however this method is time consuming and therefore costly. This report presents a method that detects, locates and quantifies the error(s) in a force balanced mechanism, after just one test run. An adjustable 1-DoF rotating mechanism is developed and a sensitivity analysis is performed to obtain the shaking force response of each parameter error. Comparing the shaking force response with the theoretical values shows the effectiveness of the adjustable 1-DoF rotating mechanism. Then the inversed relations of these shaking force responses are plotted in a design chart which can trace back the parameters that need adjusting. The method demonstrates that a 1-DoF mechanism can be balanced after just one test run.BMEBioMechanical EngineeringMechanical, Maritime and Materials Engineerin
Explicit dynamic modeling with joint friction and coupling analysis of a 5-DOF hybrid polishing robot
No full textAiming at a 5-DOF hybrid optical mirror polishing robot, the explicit dynamic model considering the joint friction is established and the inertia coupling distribution is studied. Firstly, the kinematics of the manipulator is solved based on closed-loop vector method, and the dynamic model is established with Newton-Euler method based on the force analysis of manipulator components. Secondly, the kinematic parameters of the reference point of the moving platform are selected as the intermediate variables, and the explicit dynamic model of the parallel manipulator is obtained by parameters substitution considering the friction effects of spherical joints, universal joints and ball screws. Finally, on the basis of the dynamic model, the inertia coupling strength evaluation index for active branched-chains is proposed, and the distribution law of the coupling strength in a certain trajectory and workspace is studied. The results show that the inertia coupling strength indices between active branched-chains vary with the manipulator position and are symmetrically distributed in the workspace. This paper provides a theoretical basis for the joint controller design and structural parameter optimization of the polishing robot.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport Engineering and Logistic
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