FourBar

A node.js program for a fourbar position analysis using the vector method. This library encompasses the angles of all the links and their position vectors along with the transmission angle.

#FourBar Position Analysis

This library makes for quick and easy position analysis of a simple four bar linkage. Positions may be put through a simple derivative to obtain velocities and accelerations. For a better understanding of linkages and how to engineer linked mechanisms, see Robert L. Norton's Design of Machinery. Inside this text are in depth explanations of linkages and their uses.

##Methods

|Method call|Parameters|Description| |-----------|----------|-----------| |type| N/A | 'VectorMethod'| | linkageType | inputLength, couplerLength, outputLength, groundLength | Returns type of linkage | |couplerAngle | inputLength, couplerLength, outputLength, groundLength, inputAngle | Returns and Object with open and crossed configuration angles of coupler link from the positive x-axis based on the input link angle in Radians | |outputAngle | inputLength, couplerLength, outputLength, groundLength, inputAngle | Returns and Object with open and crossed configuration angles of output link from the positive x-axis based on input link angle in Radians | |couplerVector | inputLength, couplerLength, outputLength, groundLength, inputAngle, deltaAngle | Returns Objects of the real and imaginary components of both the crossed and open configurations based on the input angle in Radians + an optional delta as seen below| |outputVector | inputLength, couplerLength, outputLength, groundLength, inputAngle, deltaAngle | Returns Objects of the real and imaginary components of both the crossed and open configurations based on the input angle in Radians + an optional delta as seen below| |inputVector | inputLength, couplerLength, outputLength, groundLength, inputAngle, deltaAngle | Returns the real and imaginary components of the input link + an optional delta|

##Parameters

In the image below, input is represented by s, the coupler is p and the output is u. Driving angle is Theta 2 and the deltas are for creating ternary links.

##Example

Below is a vary basic example to show how fast calculations can be made

const FourBar = require('fourbar');
const four = new FourBar;


let output;
let coupler;
let transmission;

const link1 = 20;
const link2 = 10;
const link3 = 10;
const link4 = 10;
angle = (75 * (Math.PI/180));


output = four.outputAngle(link2, link3, link4, link1, angle);
coupler = four.couplerAngle(link2, link3, link4, link1, angle);
transmission = four.transmissionAngle(link2, link3, link4, link1, angle);

console.log(`Crossed output angle ${(output.crossed * (180/Math.PI))} \n`);
console.log(`Open output angle ${(output.open * (180/Math.PI))} \n`);
console.log(`Crossed coupler angle ${(coupler.crossed * (180/Math.PI))} \n`);
console.log(`Open coupler angle, ${(coupler.open * (180/Math.PI))} \n`);
console.log(`TYPE: ${four.linkageType(link2, link3, link4, link1, angle)} \n`);
console.log(`Crossed transmission angle ${(transmission.crossed * (180/Math.PI))} \n`);
console.log(`Open transmission angle ${(transmission.open * (180/Math.PI))} \n`);