滑塊位置分析

利用MATLAB程式slider_ solve ()，可以計算任意曲柄角度之對應連結桿角度及水平距離，公式4.24與4.25，如程式4.8。其呼叫函數如下：

function [d,theta3]=slider_solve(theta2,R,L,e,mode)

其參數之定義詳如程式內容。

程式4.8
function [d,theta3]=slider_solve(theta2,R,L,e,mode)
% P4.8   [d,theta3]=slider_solve(theta2,R,L,e)
%
% Find the block coordinate and angle of connecting rod in a slider-crank system
% Input:R,L lengths of crank & connecting rod; e the offset of block
%       theta2: angles of crank, cane be a matrix
% Output: d:distance of the block from the origin.
%         theta3:angle of the connecting rod, 
% Examples:
%    [d,theta3]=slider_solve(45,5,10,3)
%    
% Designed by D.S. Fon, BIME, NTU, Date:Fegruary 9,2003.
if nargin<5, mode=0;end
d2g=pi/180;
theta=theta2*d2g;
cc=(e-R.*sin(theta))./L;
if mode>=0,
    theta3=asin(cc);
else
    theta3=asin(-cc)+pi;
end
d=L.*cos(theta3)+R.*cos(theta);
theta3=theta3/d2g;

範例4.9

試比較一組曲桿滑塊機構R=5cm，L=10cm，e=6 cm，試求曲柄角度為30、45、60、90度時之連結桿角及滑塊之水平距離。

[解]：

>> [d,theta3]=slider_solve([30 45 60 90],5,10,6,1)

d =    13.6976   13.2271   12.3596    9.9499
theta3 = 20.4873   14.2673    9.6127    5.7392