% MotionGenesis file: ParticlePendulumMFileForSimulink.txt
% Problem: Particle pendulum with air resistance (for Simulink).
% Copyright (c) 2009 Motion Genesis LLC.  All rights reserved.
%------------------------------------------------------------
NewtonianFrame N            % Earth
RigidFrame     B            % Massless cable.
Particle       Q            % Particle at end of cable.
%------------------------------------------------------------
Q.SetMass( m = 100 kg )
Constant  g = 9.8 m/s^2     % Earth's gravitational acceleration
Constant  L = 50 m          % Cable length 
Constant  bAir = 2.0 N*s/m  % Air-resistance constant
Variable  theta''           % Pendulum swing angle
Variable  Tension           % Tension in cable.
%------------------------------------------------------------
%       Rotation and translation kinematics
B.RotateZ( N, theta )
Q.Translate( No, -L*By> )
%------------------------------------------------------------
%       Contact and distance forces on Q.
Q.AddForce( -m*g*Ny> + Tension*By> - bAir*Q.GetVelocity(N) )
%------------------------------------------------------------
%       Form equations of motion with  F = m *a  
ZeroFma[1] = Dot( Q.GetDynamics(),  Bx> )
ZeroFma[2] = Dot( Q.GetDynamics(),  By> )
Solve( ZeroFma,  theta'',  Tension )
%------------------------------------------------------------
%       Quantities to be output by  Algebraic()  command.
OutputEncode  theta deg,  theta' rad/sec,  theta'' rad/sec^2,  Tension Newtons
Code Algebraic()  ParticlePendulumMFileForSimulink.m( theta, theta' )
%------------------------------------------------------------
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