Modeling an eccentric shaft with Simscape

Question

Martin O'Connor 2019-5-6

0
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https://ww2.mathworks.cn/matlabcentral/answers/460526-modeling-an-eccentric-shaft-with-simscape

回答： Olalowo Olaleye 2019-9-19

I am trying to model an eccentric shaft in the simscape mechanical domain, i.e. a linear displacement varying sinusoidally with a frequency proportional to the angular displacement of a shaft. I have written a component for this (see below) that seems to be working, however it is very slow to solve. Does anyone have any advice on how to make this model run more efficiently, or if there is a different method that would achieve the same thing? I have also tried using just a linear velocity source, however the displacement was drifting over time and causing the simulation to crash.

Thanks,

Martin

component EccentricShaft
nodes
    A = foundation.mechanical.rotational.rotational; % A:left
    P = foundation.mechanical.translational.translational; % P:right
end
parameters
    offset = { 0, 'rad'}; % Initial angular position
    initPos = {0, 'm'}; % Initial linear position
    eccentricity = { 0.05, 'm'}; %Shaft Eccentricity
    initV = {0, 'm/s'}; %Initial linear velocity
    initomega = {0,'rad/s'}; %Initial angular velocity
end
variables(Access = private)
    V = {value = initV, priority = priority.high}; %  V:Left
    X = {value = initPos, priority = priority.high};   %  X:Left
    F = { 0, 'N' };   %  F:Left
    theta = {value = offset, priority = priority.high}    % theta:Right
    omega = {value = initomega, priority = priority.high};  % omega:Right
    tau = { 0, 'N*m'};      % tau:Right
end
branches
    tau : A.t -> *;
    F : P.f -> *;
end
equations
    assert(eccentricity>0)
    
    X - eccentricity/2*(1-cos(theta)) == 0;
    V == P.v;
    omega == A.w;
    X.der == V;
    theta.der == omega;
    F*V - omega*tau == 0;
    
end
end