Data and analysis script for Moment of Inertia using bifilar pendulum method.

controls/MATLAB/momentOfInertia/J_calc_bifilar.m

+function  J  = J_calc_bifilar( m , g, D, L, t, n , varargin)
+%UNTITLED Summary of this function goes here
+%   Detailed explanation goes here
+
+average_strings = {'average','mean','ave'}; 
+least_squares_strings = {'least squares','ls'}; 
+
+mode = 0; 
+if ~isempty(varargin)
+    for k = 1:length(varargin)
+        if any(strcmpi(varargin{k},average_strings))
+            mode = 0; 
+        end
+        if any(strcmpi(varargin{k},least_squares_strings))
+            mode = 1; 
+        end
+    end
+end
+
+if mode == 0 %averge
+        N = length(t); 
+        Js = zeros(1,N); 
+        for k = 1:N
+            Js(k) = m(k)*g*D(k)^2/(16*pi^2*L(k))*(t(k)/n(k))^2; 
+        end        
+        J = mean(Js); 
+end
+
+if mode == 1 %least squares
+    J = (16*pi^2*L./(m*g.*D.^2))\(t./n).^2 ; 
+end
+
+
+
+end
+

controls/MATLAB/momentOfInertia/J_calc_bifilar_script.m

+
+% inches2meters = 0.0254 ; 
+
+%%
+% %Jxx
+% m = 1.244*ones(5,1); 
+% D = (12+3/8)*inches2meters*ones(5,1); 
+% L = (81+3/4)*inches2meters*ones(5,1); 
+% t = [ 94.58 ; 93.91 ; 93.81 ; 94.16 ; 94.04 ] ; 
+% n = 50*ones(5,1); 
+
+% %Jyy
+% m = 1.244*ones(5,1); 
+% D = (12+3/8)*inches2meters*ones(5,1); 
+% L = (91+3/4)*inches2meters*ones(5,1); 
+% t = [ 103.31 ; 103.15 ; 103.31 ; 103.47 ; 103.13 ] ; 
+% n = 50*ones(5,1); 
+
+
+% %Jzz 
+% m = 1.244*ones(5,1); 
+% D = (19+3/16)*inches2meters*ones(5,1); 
+% L = (96+1/4)*inches2meters*ones(5,1); 
+% t = [ 96.64 ; 97.47 ; 97.75 ; 97.35 ; 97.78 ] ; 
+% n = 50*ones(5,1); 
+
+load .\git_repos\microCART_17-18\controls\dataCollection\bifilar_inertia_2_18_2017\MicroCART_bifilar_Jxx_2_18_2017 ; 
+Jxx_a = J_calc_bifilar( m , g, D, L, t, n , 'average')
+Jxx_ls = J_calc_bifilar( m , g, D, L, t, n , 'least squares')
+
+clear D L m n t 
+load .\git_repos\microCART_17-18\controls\dataCollection\bifilar_inertia_2_18_2017\MicroCART_bifilar_Jyy_2_18_2017 ; 
+Jyy_a = J_calc_bifilar( m , g, D, L, t, n , 'average')
+Jyy_ls = J_calc_bifilar( m , g, D, L, t, n , 'least squares')
+
+clear D L m n t 
+load .\git_repos\microCART_17-18\controls\dataCollection\bifilar_inertia_2_18_2017\MicroCART_bifilar_Jzz_2_18_2017 ; 
+Jzz_a = J_calc_bifilar( m , g, D, L, t, n , 'average')
+Jzz_ls = J_calc_bifilar( m , g, D, L, t, n , 'least squares')