1,751,235 research outputs found
Platform Portable Anthropomorphic Grasping with the Bielefeld 20-DOF Shadow and 9-DOF TUM Hand
Full text linkRöthling F, Haschke R, Steil JJ, Ritter H. Platform Portable Anthropomorphic Grasping with the Bielefeld 20-DOF Shadow and 9-DOF TUM Hand. In: Proc. Int. Conf. on Intelligent Robots and Systems (IROS). IEEE; 2007: 2951-2956
Thermal Actuation Based 3-DoF Non-Resonant Microgyroscope Using MetalMUMPs
Full text linkHigh force, large displacement and low voltage consumption are a primary concern for microgyroscopes. The chevron-shaped thermal actuators are unique in terms of high force generation combined with the large displacements at a low operating voltage in comparison with traditional electrostatic actuators. A Nickel based 3-DoF micromachined gyroscope comprising 2-DoF drive mode and 1-DoF sense mode oscillator utilizing the chevron-shaped thermal actuators is presented here. Analytical derivations and finite element simulations are carried out to predict the performance of the proposed device using the thermo-physical properties of electroplated nickel. The device sensitivity is improved by utilizing the dynamical amplification of the oscillation in 2-DoF drive mode using an active-passive mass configuration. A comprehensive theoretical description, dynamics and mechanical design considerations of the proposed gyroscopes model are discussed in detail. Parametric optimization of gyroscope, its prototype modeling and fabrication using MetalMUMPs has also been investigated. Dynamic transient simulation results predicted that the sense mass of the proposed device achieved a drive displacement of 4.1 μm when a sinusoidal voltage of 0.5V is applied at 1.77 kHz exhibiting a mechanical sensitivity of 1.7 μm /degrees/s in vacuum. The wide bandwidth frequency response of the 2-DoF drive mode oscillator consists of two resonant peaks and a flat region of 2.11 kHz between the peaks defining the operational frequency region. The sense mode resonant frequency can lie anywhere within this region and therefore the amplitude of the response is insensitive to structural parameter variations, enhancing device robustness against such variations. The proposed device has a size of 2.2 x 2.6 mm2, almost one third in comparison with existing M-DoF vibratory gyroscope with an estimated power consumption of 0.26 Watts. These predicted results illustrate that the chevron-shaped thermal actuator has a large voltage-stroke ratio shifting the paradigm in MEMS gyroscope design from the traditional interdigitated comb drive electrostatic actuator. These actuators have low damping compared to electrostatic comb drive actuators which may result in high quality factor microgyroscopes operating at atmospheric pressure
Reconfiguration analysis of a 3-DOF parallel mechanism using Euler parameter quaternions and algebraic geometry method
No full textThis paper deals with the reconfiguration analysis of a 3-DOF (degrees-of-freedom) parallel mechanism (PM) with multiple operation modes - a disassembly-free reconfigurable PM - using the Euler parameter quaternions and algebraic geometry approach. At first, Euler parameter quaternions are classified into 15 cases based on the number of constant zero components and the kinematic interpretation of different cases of Euler parameter quaternions is presented. A set of constraint equations of a 3-RER PM with orthogonal platforms is derived with the orientation of the moving platform represented using a Euler parameter quaternion and then solved using the algebraic geometry method. It is found that this 3-RER PM has 15 3-DOF operation modes, including four translational modes, six planar modes, four zero-torsion-rate motion modes and one spherical mode. The transition configurations, which are singular configurations, among different operation modes are also presented. Especially, the transition configurations in which the PM can switch among eight operation modes are revealed for the first time.</p
DoF-Gaussian: Controllable Depth-of-Field for 3D Gaussian Splatting
No full textRecent advances in 3D Gaussian Splatting (3D-GS) have shown remarkable success in representing 3D scenes and generating high-quality, novel views in real-time. However, 3D-GS and its variants assume that input images are captured based on pinhole imaging and are fully in focus. This assumption limits their applicability, as real-world images often feature shallow depth-of-field (DoF). In this paper, we introduce DoF-Gaussian, a controllable depth-of-field method for 3D-GS. We develop a lens-based imaging model based on geometric optics principles to control DoF effects. To ensure accurate scene geometry, we incorporate depth priors adjusted per scene, and we apply defocus-to-focus adaptation to minimize the gap in the circle of confusion. We also introduce a synthetic dataset to assess refocusing capabilities and the model’s ability to learn precise lens parameters. Our framework is customizable and supports various interactive applications. Extensive experiments confirm the effectiveness of our method
A 2T-2R, 4-DOF PARALLEL MANIPULATOR
No full textFrom the first ideas of parallel manipulator proposed by Gough and Stewart, parallel manipulators have been found in many industrial applications. In the past two decades, a number of interesting mechanical devices and design methods have been extensively studied. However, most efforts are dedicated to six degrees of freedom (6-DOF) or 3-DOF manipulators. There is a need for equipment providing more than 3 DOF/s arranged in parallel and based on simpler arrangements than 6-DOF arrangements in pplication. This paper presents a novel 4-DOF parallel platform manipulator with base mounted prismatic actuators. The movable platform of the manipulator can translate along two directions and rotate around two axes respectively (2T-2R). The kinematics model is formulated, which describes the inverse and forward kinematics transformation. The singularity analysis of this new 2T-2R, 4-DOF parallel manipulator is introduced
Kinematic analysis of a single-loop reconfigurable 7R mechanism with multiple operation modes
Full text linkThis paper presents a novel one-degree-of-freedom (1-DOF) single-loop reconfigurable 7R mechanism with multiple operation modes (SLR7RMMOM), composed of seven revolute (R) joints, via adding a revolute joint to the overconstrained Sarrus linkage. The SLR7RMMOM can switch from one operation mode to another without disconnection and reassembly, and is a non-overconstrained mechanism. The algorithm for the inverse kinematics of the serial 6R mechanism using kinematic mapping is adopted to deal with the kinematic analysis of the SLR7RMMOM. First, a numerical method is applied and an example is given to show that there are 13 sets of solutions for the SLR7RMMOM, corresponding to each input angle. Among these solutions, nine sets are real solutions, which are verified using both a computer-aided design (CAD) model and a prototype of the mechanism. Then an algebraic approach is also used to analyse the mechanism and same results are obtained as the numerical one. It is shown from both numerical and algebraic approaches that the SLR7RMMOM has three operation modes: a translational mode and two 1-DOF planar modes. The transitional configurations among the three modes are also identified
Extending 3-DoF Metrics to Model User Behaviour Similarity in 6-DoF Immersive Applications
Full text linkImmersive 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
A PC-Based Configuration Controller for Dexterous 7-DOF Arms
No full textThis paper describes the architecture and performance of a PC-based configuration controller for dexterous 7-DOF manipulators. The computing platform is a 486-based personal computer equipped with a bus extender to access the robot Multibus controller, together with a single-board computer as the graphical engine, and a parallel I/O board to interface with a force-torque sensor mounted on the manipulator wrist. The Windows TM environment is enhanced by the iRMX flR real-time operating system that runs the configuration control algorithms for redundancy resolution. The position control algorithm is executed every 2:5 ms; motions can be simulated and displayed in real-time by the graphical engine on a separate monitor. The results of several experiments carried out with a Robotics Research manipulator have shown motion control capabilities comparable to those obtained with more extensive computing systems, thus validating the use of PC's for dexterous manipulator control. PCbased moti..
Report of the Review Session of Output and Outcome Country Achievements
No full textThis report is under the SEAFDEC/UNEP/GEF Project on “Establishment and Operation of a Regional System of Fisheries Refugia in the South China Sea and Gulf of Thailand”DOF/Malaysia organized the meeting to discuss the results of the finalization of the Management Plan Measures for Lobster Refugia in Tanjung Leman, Johore, and Tiger Prawn Refugia in Kuala Baram, Sarawak. In addition, DOF/MY also updated the output and outcome achievement of the country while informing the progressive steps of project implementation before the project's end date.UNEP/GE
A novel 4-DOF parallel manipulator and its kinematic modelling
No full textIn this paper a novel four-degree-of-freedom (4-DOF) hybrid parallel platform manipulator is presented. The movable platform of the parallel manipulator can translate along two directions and rotate around two axes respectively. The kinematics model is formulated, which describes the inverse kinematic, transformation and forward kinematic transformation. A 5-axis parallel machine tool based on the 4-DOF parallel manipulator is presented in this paper
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