Static Equilibrium of Spatial Mechanisms With Cylindrical Joints

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Ian S. Fischer
Keyword(s):  
Input Data ◽  
Closed Loop ◽  
Static Equilibrium ◽  
Spatial Mechanisms ◽  
Cylindrical Joint ◽  
Set Up

The components of force and torque acting on a joint of a link in static equilibrium are partitioned according to the type of joint so that the equations of static equilibrium can be set up automatically by computer where the type of each joint has been specified in the input data. Special attention is given to the cylindrical joint, and the implications of the geometry of an intermediate link with a cylindrical joint on both ends are examined. While the methodology is demonstrated for the RCCC mechanism, which features a revolute input joint and cylindrical intermediate and output joints, it is adaptable to closed-loop mechanisms of binary links with any kind of joint in any position.

Relative Acceleration in Spatial Mechanisms

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
Ian S. Fischer
Keyword(s):  
Closed Loop ◽  
Number Representation ◽  
Automatic Computation ◽  
Dual Number ◽  
Spatial Mechanisms ◽  
Relative Acceleration ◽  
Set Up ◽  
Derivatives Of

A scheme applicable to automatic computation of the joint relative accelerations, the derivatives of joint speeds with respect to time, has been developed in the dual-number representation of the kinematics of spatial mechanisms. The equations which have been developed can be set up automatically by computer for any closed-loop mechanism of binary links. While the RCCC mechanism is given as an example, the scheme can be adapted for mechanisms with prismatic as well as revolute and cylindrical joints and can be readily further developed to consider other types of joints.

The application of compound proportional resonant control strategy in multiple PV inverters system

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840098
Author(s):  
Yuan Li ◽  
Huifang Shen ◽  
Chao Xiong ◽  
Yaofei Han ◽  
Guofeng He
Keyword(s):  
Control Strategy ◽  
Closed Loop ◽  
Control Strategies ◽  
Integrated Control ◽  
Reference Signal ◽  
Loop Model ◽  
Harmonic Compensation ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Set Up

In order to eliminate the effect on the grid current caused by the background harmonic voltage and the reference signal on the grid connected multi-inverter, this paper adopts the double closed-loop feed-forward control strategy. This strategy is based on the inductor voltage and the grid-connected current, and the integrated control strategy of quasi-proportional resonance loop parallel to a specific harmonic compensation loop. Based on the closed-loop model of multiple inverters, the change curves of the transfer function of the two control strategies are compared with the feed-forward control and the composite proportional resonance. The two corresponding control methods are used to analyze the current quality of the multi-inverter impact. Finally, the MATLAB/Simulink simulation model is set up to verify the proposed control strategies. The simulation results show that the proposed method can achieve better tracking of the sinusoidal command signal at the fundamental frequency, and enhance the anti-interference ability of the system at the 3rd, 5th, and 7th harmonic frequency.

A Digital Computer Model for Optimal Programming of Hemodialytic Treatment

1988 ◽  
Vol 11 (4) ◽  
pp. 235-242 ◽  
Author(s):  
C. Lamberti ◽  
E. Sarti ◽  
A. Santoro ◽  
M. Spongano ◽  
P. Zucchelli ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Closed Loop ◽  
Clinical Results ◽  
Pressure Regulation ◽  
Clinical Tests ◽  
Experimental Protocol ◽  
Dialysis Unit ◽  
Optimal Programming ◽  
Set Up ◽  
Arterial Pressure Regulation

A mathematical model of hydroelectrolyte exchanges and arterial pressure regulation in the human body during dialysis has been set up. It is conceived as a tool for a new dialysis unit which will be able to “interpret” the signals supplied by suitable instruments connected to the patient and modify the machine set-points in real time in order to obtain clinical results defined by the physician. The main aim is the prevention of hypotensive episodes during treatment. An experimental protocol has been developed for parameter estimation of each patient during a single dialysis. Clinical tests illustrated the model's ability to fit the patient's state during dialysis. This is the first step in the more general task of validation of the model, necessary for the achievement of a closed-loop dialysis unit.

scholarly journals Distance-Based Formation Control for Quadrotors with Collision Avoidance via Lyapunov Barrier Functions

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Jawhar Ghommam ◽  
Luis F. Luque-Vega ◽  
Maarouf Saad
Keyword(s):  
Collision Avoidance ◽  
Tracking Control ◽  
Formation Control ◽  
Closed Loop ◽  
Group Formation ◽  
Closed Loop System ◽  
Relative Localization ◽  
Formation Pattern ◽  
Set Up ◽  
The Stability

In this paper, group formation control with collision avoidance is investigated for heterogeneous multiquadrotor vehicles. Specifically, the distance-based formation and tracking control problem are addressed in the framework of leader-follower architecture. In this scheme, the leader is assigned the task of intercepting a target whose velocity is unknown, while the follower quadrotors are arranged to set up a predefined rigid formation pattern, ensuring simultaneously interagent collision avoidance and relative localization. The adopted strategy for the control design consists in decoupling the quadrotor dynamics in a cascaded structure to handle its underactuated property. Furthermore, by imposing constraints on the orientation angles, the follower will never be overturned. Rigorous stability analysis is presented to prove the stability of the entire closed-loop system. Numerical simulation results are presented to validate the proposed control strategy.

scholarly journals Impact of Component Dispersion in DC to DC Low-Power Low-Voltage Power Converter Array

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 917
Author(s):  
Jean-Christophe CREBIER ◽  
Theo LAMORELLE ◽  
Silvain MARACHE ◽  
Thanh Hai PHUNG ◽  
Van-Sang NGUYEN ◽  
...  
Keyword(s):  
Closed Loop ◽  
Low Voltage ◽  
Power Converter ◽  
Point Of View ◽  
Statistical Point ◽  
Loop Control ◽  
In Series ◽  
And Performance ◽  
Set Up ◽  
The Impact

The paper deals with arrays of numerous power conversion cells, associated in series and/or in parallel to build larger step up or step down direct current (DC)/DC isolated converters. The work focuses on the impact of the spread and distribution of the conversion cell characteristics on the characteristics and performance of the power converter array (PCA). Based on a characterization protocol, about 130 conversion standard cells (CSC) are characterized and classified from a statistical point of view. Three families are defined and representatives are chosen and implemented in various configurations, in open and closed loop control, to analyze the impact of their spread characteristic over the global converter, the PCA. The paper is based on an extended practical set up and protocols, all described in details. Guidelines on CSCs implementation with respect to their dispersion are provided at the end on the paper.

scholarly journals Developing a Coupling Model System of Global Rainfall Data and Open-Source Model for Water Forecast in Poorly Gauged Basins

2019 ◽  
Vol 3 (1) ◽  
pp. 355 ◽  
Author(s):  
Duong Du Bui ◽  
Duc Minh Tran ◽  
Huong Thi Vu ◽  
Nuong Thi Bui
Keyword(s):  
Open Source ◽  
Input Data ◽  
Water Security ◽  
Coupling Model ◽  
Source Model ◽  
Rainfall Data ◽  
Creative Commons ◽  
Set Up ◽  
User Friendly

Water security is under severe pressures from human interventions and climate change in all over the world and improved water forecast is essential for water management. HYPE is a semi-distributed hydrographic model, running on Windows or Linux operating systems. The code of the model is written by the Fortran programming language and open source as Lesser GNU Public License. HYPE has been becoming a widely used tool in the forecasting of transboundary flows. However, the application of HYPE encounters many difficulties in processing input data and serving the construction, calibration, and validation of the model. This article introduces the development of the V-HYPE tool that helps a couple of global rainfall data and HYPE model for operational use. V-HYPE allows developing a user-friendly interface and setting parameters of the HYPE model as well as evaluating errors and transforming and visually displaying the results of the model. Besides, the V-HYPE has the ability to show related maps (i.e. sub-basins, river network, lake, and dams, etc), set up input data, automatically download global rainfall data, and visually display results on WebGIS. V-HYPE also can generate bulletins supporting for operational water resources warning and forecasting works in Vietnam. The utilities of this tool are demonstrated in the case study of Serepok river basin.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

scholarly journals Open source modules for tracking animal behavior and closed-loop stimulation based on Open Ephys and Bonsai

2018 ◽  
Author(s):  
Alessio Paolo Buccino ◽  
Mikkel Elle Lepperød ◽  
Svenn-Arne Dragly ◽  
Philipp Häfliger ◽  
Marianne Fyhn ◽  
...  
Keyword(s):  
Open Source ◽  
Real Time ◽  
Closed Loop ◽  
Low Cost ◽  
Data Formats ◽  
Behavioral Tracking ◽  
Real Time Tracking ◽  
Set Up ◽  
And Behavior ◽  
Closed Loop Stimulation

AbstractObjectiveA major goal in systems neuroscience is to determine the causal relationship between neural activity and behavior. To this end, methods that combine monitoring neural activity, behavioral tracking, and targeted manipulation of neurons in closed-loop are powerful tools. However, commercial systems that allow these types of experiments are usually expensive and rely on non-standardized data formats and proprietary software which may hinder user-modifications for specific needs. In order to promote reproducibility and data-sharing in science, transparent software and standardized data formats are an advantage. Here, we present an open source, low-cost, adaptable, and easy to set-up system for combined behavioral tracking, electrophysiology and closed-loop stimulation.ApproachBased on the Open Ephys system (www.open-ephys.org) we developed multiple modules to include real-time tracking and behavior-based closed-loop stimulation. We describe the equipment and provide a step-by-step guide to set up the system. Combining the open source software Bonsai (bonsai-rx.org) for analyzing camera images in real time with the newly developed modules in Open Ephys, we acquire position information, visualize tracking, and perform tracking-based closed-loop stimulation experiments. To analyze the acquired data we provide an open source file reading package in Python.Main resultsThe system robustly visualizes real-time tracking and reliably recovers tracking information recorded from a range of sampling frequencies (30-1000Hz). We combined electrophysiology with the newly-developed tracking modules in Open Ephys to record place cell and grid cell activity in the hippocampus and in the medial entorhinal cortex, respectively. Moreover, we present a case in which we used the system for closed-loop optogenetic stimulation of entorhinal grid cells.SignificanceExpanding the Open Ephys system to include animal tracking and behavior-based closed-loop stimulation extends the availability of high-quality, low-cost experimental setup within standardized data formats serving the neuroscience community.

scholarly journals Spatial Mechanism Design in Virtual Reality With Networking

2001 ◽  
Author(s):  
John N. Kihonge ◽  
Judy M. Vance ◽  
Pierre M. Larochelle
Keyword(s):  
Virtual Reality ◽  
Finite Sequence ◽  
Degree Of Freedom ◽  
Three Dimensions ◽  
Synthesis Process ◽  
Spatial Mechanisms ◽  
Cylindrical Joint ◽  
In Series ◽  
Simply Connected ◽  
Two Degree Of Freedom

Abstract Mechanisms are used in many devices to move a rigid body through a finite sequence of prescribed locations in space. The most commonly used mechanisms are four-bar planar mechanisms that move an object in one plane in space. Spatial mechanisms allow motion in three-dimensions (3D). Spatial 4C mechanisms are two degree of freedom kinematic closed-chains consisting of four rigid links simply connected in series by cylindrical (C) joints. A cylindrical joint is a two degree of freedom joint which allows translation along and rotation about a line in space. This paper describes a synthesis process for the design of 4C spatial mechanisms in a virtual environment. Virtual reality allows the user to view and interact with digital models in a more intuitive way than using the traditional human-computer interface (HCI). The software developed as part of this research also allows multiple users to network and share the designed mechanism. Networking tools have the potential to greatly enhance communication between members of the design team at different industrial sites and therefore reduce design costs.

Geometric Insight Into the Dynamics of a Rigid Body Using the Spatial Triangle of Screws

2001 ◽  
Author(s):  
Gordon R. Pennock ◽  
Patrick J. Meehan
Keyword(s):  
Rigid Body ◽  
Closed Loop ◽  
Equations Of Motion ◽  
Analytical Techniques ◽  
Rate Of Change ◽  
Time Rate ◽  
Open Chain ◽  
Spatial Mechanisms ◽  
Kinetics Of ◽  
Insight Into

Abstract Geometric relationships between the velocity screw and momentum screw are presented, and the dual angle between these two screws is shown to provide important insight into the kinetics of a rigid body. Then the centripetal screw is defined, and the significance of this screw in a study of the dynamics of a rigid body is explained. The dual-Euler equation, which is the dual form of the Newton-Euler equations of motion, is shown to be a spatial triangle. The vertices of the triangle are the centripetal screw, the time rate of change of momentum screw, and the force screw. The sides of the triangle are three dual angles between the three vertices. The spatial triangle provides valuable geometrical insight into the dynamics of a rigid body and is believed to be a meaningful alternative to existing analytical techniques. The authors believe that the work presented in this paper will prove useful in a dynamic analysis of closed-loop spatial mechanisms and multi-rigid body open-chain systems.

scholarly journals Modelling of surface river plume using set-up and input data files of Delft-3D model

Data in Brief ◽  
2020 ◽  
Vol 31 ◽  
pp. 105899
Author(s):  
Juan Gabriel Rueda-Bayona ◽  
José Horrillo-Caraballo ◽  
Tatiana R. Chaparro
Keyword(s):  
Input Data ◽  
3D Model ◽  
River Plume ◽  
Data Files ◽  
Set Up
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