Design and motion analysis of a small motor stator multi-wire paralleled winding hybrid robot

The working space of small motor stators is narrow, and most of them are manual winding. It is difficult to guarantee the uniform arrangement of enameled wires by multi-wire winding. To solve these problems, a three-phase parallel equivalent multi-wire winding robot is proposed to achieve large output torque of the motor. Firstly, according to the equivalent model, the structure of the large arm, small arm and manipulator is designed to determine the motion model of the winding robot. Euler's kinematics theory is used to analyze the change of the working position of the arm, and the rotation matrix of the arm and the constraint equation of the motion vector of each branch chain are established. The motion model of the arm and the manipulator are established using inverse kinematics and analytical analysis. The motion pose of each joint of the winding robot is studied to ensure that the robot realizes a three-phase parallel multi-wire winding motion. ADAMS software was used for kinematic simulation analysis of the winding robot. The displacement of the branch chain on the xyz axis was represented by the torque of the virtual motor to verify the correctness of the inverse kinematics solution and the closure condition of the manipulator block. Finally, the ROS simulation platform is built to simulate the joint motion planning of the winding robot to verify the multi-line parallel principle and the feasibility of the multi-line parallel winding hybrid robot. The research results of this paper provide a theoretical reference for multi-wire parallel winding equipment control.

Representation of model error through process-based perturbations for ensemble prediction : application to turbulence and shallow convection parametrisations

<p>The boundary layer is the place of many complex physical processes spanning various time and space scales, part of which need to be parametrised in NWP models. These parametrisations are known sources of uncertainty in the models, due to the difficulty of accurately representing the processes, and the resulting simplifications and approximations that have to be done. Model uncertainty is part of what ensemble prediction systems seek to represent. This can be achieved in particular by using stochastic perturbation methods, where noise is introduced during model computations to change its state and produce different simulations. Well-known and widely used perturbation schemes like the Stochastically Perturbed Parametrisation Tendencies (SPPT) scheme have shown their effectiveness and their interest in building ensembles. However, part of the model uncertainty is not yet well represented in current ensemble systems, while some of the assumptions made by SPPT can be questioned. This argues for a diversity of approaches to represent model errors. In this active research field, alternative perturbation methods are investigated, such as the Stochastically Perturbed Parametrisations (SPP) method, or other methods focusing on the perturbation of particular physical processes. The work presented here focuses on the last ones. Based on two examples of methods published in the literature, perturbations have been applied to the turbulence and shallow convection parametrisation schemes of the mesoscale NWP model Arome from Météo-France. The perturbation of turbulence is based on the use of subgrid-scale variances to regulate the amplitude of an additive noise, while shallow convection is perturbed through a stochastic closure condition of the scheme. A simplified 1D framework has been used, in order to assess the ability of the method to produce an ensemble with sufficient dispersion and to compare its results with those from existing methods like SPPT.</p>

How obligatory irrelevance, symmetric alternatives, and dense scales conspire: The case of modified numerals and ignorance

Buccola & Haida (2019) explore the consequences of a semantic-pragmatic theory in which relevance is closed under speaker belief. A primary consequence of this closure condition, they show, is that the Maxim of Quantity commits speakers to expressing their epistemic state about every relevant proposition. We argue that this commitment, dubbed Strong Epistemic Transparency, explains the contrast in ignorance inferences exhibited by non-strict comparative expressions like at least vs. strict ones like more than (hence the class A/B distinction of Nouwen 2010). We also discuss how our analysis might be extended to account for the observations of Cummins, Sauerland & Solt (2012) and Enguehard (2018) that the modifier more than does not block scalar inferences of round numerals.

T 3-invariant heterotic Hull-Strominger solutions

We consider the heterotic string on Calabi-Yau manifolds admitting a Strominger-Yau-Zaslow fibration. Upon reducing the system in the T3-directions, the Hermitian Yang-Mills conditions can then be reinterpreted as a complex flat connection on ℝ3 satisfying a certain co-closure condition. We give a number of abelian and non-abelian examples, and also compute the back-reaction on the geometry through the non-trivial α′-corrected heterotic Bianchi identity, which includes an important correction to the equations for the complex flat connection. These are all new local solutions to the Hull-Strominger system on T3× ℝ3. We also propose a method for computing the spectrum of certain non-abelian models, in close analogy with the Morse-Witten complex of the abelian models.

Optimal wrench-closure configuration of spatial reconfigurable cable-driven parallel robots

In this paper, a method for computing the optimal actuation of reconfigurable cable-driven parallel robots is presented. By using this method, the imperfect ability in exerting torque and limited orientation workspace of these robots may be improved. In a cable-driven parallel robot with reconfigurability, the attachment points of cables on the base are adjusted with regard to the movement of the end-effector on a trajectory. In such a design the redundant degree-of-freedom of the robot is increased accordingly. For an arbitrary pose of the end-effector, a spherical zone is defined in which the called wrench-closure condition is satisfied for a prescribed range of orientation. Taking the volume of such zone into consideration the optimal configuration of the robot may be determined. This configuration is found by appropriately changing the position of the moving attachment points on the base of the robot. By repeating this computation for a number of points on a specified trajectory, appropriate actuation plans are achieved. The computed optimal actuation guarantees balance of any external wrench by tension force of cables when the end-effector moves close to its trajectory. For a case of spatial reconfigurable cable-driven parallel robot, the optimal actuation is found based on Particle Swarm Optimization and performance of the robot is compared to the one with fixed cable attachment points on base. The result shows significant improvement of the performance of reconfigurable spatial cable-driven parallel robot.

Real-time hydraulic fracture monitoring and wellbore characterization with distributed acoustic sensing of pumping noise

The strong and regular acoustic signal provided by working pumps spreads along a well based on wellbore geometrical and physical attributes. This signal can be used to devise well properties through the interpretation of distributed acoustic data collected along a zone of interest. Any well feature that is an irregularity of the well scheme, such as tubing expansion, fluid-to-fluid interface, or an adjacent hydraulic fracture, porous reservoir, or annular compartment, can be characterized this way. Every pump generates a plurality of harmonic frequencies; thus, there are plenty of data for inversion for feature parameters. We describe a quantitative inversion workflow and give synthetic examples of hydraulic fracture monitoring and hydraulic port open/closure condition monitoring. We also stress that interference of the pump signal by the flow noise signal should be accounted for in distributed acoustic sensing interpretation.

Optimized Lossless Embedded Compression for Mobile Multimedia Applications

Power consumption is a critical design factor in modern mobile chip design, in which the memory system with dynamic random-access memory (DRAM) consumes more than half of the entire system’s power. Without DRAM bandwidth compression, extreme multimedia operations such as 8K high dynamic range (HDR) recording and 8K video conference calling are not possible without sacrificing image quality or trimming because of thermal limitations or battery time sustainability constraints. Since heterogeneous processors are substantially involved in managing various types of fallbacks or software solutions, complicated compression algorithms for high-compression ratios are not actually adaptable owing to timing closure problems or high throughput requirements. In this paper, we propose evaluation metrics to assess lossless embedded compression (LEC) algorithms to reflect realistic design considerations for mobile multimedia scenarios. Furthermore, we introduce an optimized LEC implementation for contemporary multimedia applications in mobile devices based on the proposed metrics. The proposed LEC implementation enhances the compression ratio of LEC algorithms in other commercial application processors for contemporary premium smartphones by up to 9.2% on average, while maintaining the same timing closure condition.

Multi-scale global reconstruction of water fluxes and states with mHM

<p>Land surface and hydrologic models (LSM/HMs) have been typically calibrated with streamflow for selected river basins. This procedure, although it is the current standard, it is highly disadvantageous because the resulting model 1) is not transferable to other locations and scales, 2) it underperforms against multivariate data not used during calibration, and 3) simulated fluxes do not fulfill the flux-matching closure condition [1] if compared across scales. These shortcomings lead to parameter fields exhibiting artifacts and sharp discontinuities over space (not seamless) [2] and thus, to a poor spatial representation of water fluxes and states. Existing terrestrial water cycle observations have spatial supports ranging from few hundred square meters to hundred square kilometers. Currently, most of the existing LSM/HMs are not able to assimilate simultaneously these observations because they do not have scale-invariant parameterizations. Preliminary tests at continental scale indicate that nested multiscale simulations are possible only if the model exhibits a scale-invariant parameterization [3]. In mHM [4], this capability is provided via the multiscale parameter regionalization (MPR) technique [1].</p><p>In this study, transfer-function parameters for mHM are estimated with 5500 GRDC streamflow time series, tens of FLUXNET evapotranspiration products, and the terrestrial total water storage anomaly (GRACE). This parameter estimation problem at global-scale requires a powerful supercomputer (JUWELS) [5] and the usage of recently implemented and extremely efficient parallelized algorithms [6]. The daily reconstructed high-resolution hydrologic simulations (0.25°) since 1950 reveal that the use of the MPR technique improves the overall model efficiency (compared to other global models [7]) and allows us to identify locations of consistent changes in hydrologic variables responding to long-term climate variability. The median of the NSE for the uncalibrated mHM model over the selected GRDC stations reaches a value of 0.40 for daily streamflow. Models reported in Beck et al. [7] exhibit a mean value of -0.09! This indicates the great potential of the proposed method. Comparison of terrestrial water storage (TWS) of GRACE against mHM simulations reveals hotspots of weaker model performance in regions where the water balance closure error is large. </p><p><strong>References</strong></p><p>[1] https://doi.org/10.1029/2008WR007327<br>[2] https://doi.org/10.5194/hess-21-4323-2017<br>[3] https://doi.org/10.1175/JHM-D-15-0054.1<br>[4] www.ufz.de/mhm<br>[5] http://www.fz-juelich.de/ias/jsc/juwels<br>[6] https://meetingorganizer.copernicus.org/EGU2019/EGU2019-8129-1.pdf<br>[7] https://doi.org/10.1002/2015WR018247</p>