Need help with car suspension dampening, current code is exp growing.

2 ビュー (過去 30 日間)
Levi Mikesell
Levi Mikesell 2022 年 12 月 2 日
コメント済み: Chris 2022 年 12 月 2 日
Currently trying to model a cars suspension as it runs over a bump, however, my current code is actually growing intstead of dampening. Below are the assignment details as well, my current code:
clear
Mc = 401; %Weight
Mw = 48; %Wheel Mass
Ds = 2300; % Susp Damping Coef
Cs = 230000; % Susp Spring Coef
Cw = 250000; %Wheel Spring Coef
Wact = 0.001; % WActuator Time Const
t = 0; %intial Time
dt = 0.001;
Zc = 0; % Displacement Chass
Zw = 0; % Displacement Wheel
Zr = 0; %Disp Road
Vw = 0; %intial speed wheel vertical
Vc = 0; %intial speed Chassis Vertical
U=0;
alp = 0;
bet = 0;
u = U*exp(-alp*(t(end)-t(1)))*cos(2*pi*bet*(t(end)-t(1)));
Fs = 0; %leaving as 0 until we figure out the non-damp force graphing
Fs(end+1) = Fs(end) + ((Fs(end)/Wact)+(1/Wact)*u)*dt; %Damp force
Aw = 0; %intial Wheel Acc
Ac = 0; %intial Chassis Acc
while t(end) < 5
if t(end) > 1 && t(end) < 1.11
Zr = -0.5;
Aw(end+1) = -(1/Mw)*((Cw+Cs)*Zw(end) + Cs*Zc(end) + Ds*(Vc(end) - Vw(end)) + Cw*Zr(end)-Fs(end));
Vw(end+1) = Vw(end) + Aw(end)*dt;
Zw(end+1) = Zw(end) + Vw(end)*dt;
Ac(end+1) = (1/Mc)*(Cs*(Zw(end)-Zc(end))+Ds*(Vw(end)-Vc(end))+Fs(end));
Vc(end+1) = Vc(end) + Ac(end)*dt;
Zc(end+1) = Zc(end) + Vc(end)*dt;
t(end+1) = t(end) + dt;
else
Zr = 0;
Aw(end+1) = -(1/Mw)*((Cw+Cs)*Zw(end) + Cs*Zc(end) + Ds*(Vc(end) - Vw(end)) + Cw*Zr(end)-Fs(end));
Vw(end+1) = Vw(end) + Aw(end)*dt;
Zw(end+1) = Zw(end) + Vw(end)*dt;
Ac(end+1) = (1/Mc)*(Cs*(Zw(end)-Zc(end))+Ds*(Vw(end)-Vc(end))+Fs(end));
Vc(end+1) = Vc(end) + Ac(end)*dt;
Zc(end+1) = Zc(end) + Vc(end)*dt;
t(end+1) = t(end) + dt;
end
end
plot(t,Zc)
% position, velocity, acceleration of the wheel/chass

回答 (1 件)

Chris
Chris 2022 年 12 月 2 日
Looking at the image, a_w and a_c are independent of previous acceleration values.
Aw(end+1) = -(1/Mw)*((Cw+Cs)*Zw(end) + Cs*Zc(end) + Ds*(Vc(end) - Vw(end)) + Cw*Zr(end)-Fs(end));
Ac(end+1) = (1/Mc)*(Cs*(Zw(end)-Zc(end))+Ds*(Vw(end)-Vc(end))+Fs(end));
You also have pulled a minus sign to the front, when it should only apply to the first term.
Aw(end+1) = (1/Mw)*(-(Cw+Cs)*Zw(end) + Cs*Zc(end) + Ds*(Vc(end) - Vw(end)) + Cw*Zr(end)-Fs(end));
I offer no guarantees on the validity of the rest of your code.
clear
Mc = 401; %Weight
Mw = 48; %Wheel Mass
Ds = 2300; % Susp Damping Coef
Cs = 230000; % Susp Spring Coef
Cw = 250000; %Wheel Spring Coef
Wact = 0.001; % WActuator Time Const
t = 0; %intial Time
dt = 0.001;
Zc = 0; % Displacement Chass
Zw = 0; % Displacement Wheel
Zr = 0; %Disp Road
Vw = 0; %intial speed wheel vertical
Vc = 0; %intial speed Chassis Vertical
U=0;
alp = 0;
bet = 0;
u = U*exp(-alp*(t(end)-t(1)))*cos(2*pi*bet*(t(end)-t(1)));
Fs = 0; %leaving as 0 until we figure out the non-damp force graphing
Fs(end+1) = Fs(end) + ((Fs(end)/Wact)+(1/Wact)*u)*dt; %Damp force
Aw = 0; %intial Wheel Acc
Ac = 0; %intial Chassis Acc
while t(end) < 5
if t(end) > 1 && t(end) < 1.11
Zr = -0.5;
Aw(end+1) = (1/Mw)*(-(Cw+Cs)*Zw(end) + Cs*Zc(end) + Ds*(Vc(end) - Vw(end)) + Cw*Zr(end)-Fs(end));
Vw(end+1) = Vw(end) + Aw(end)*dt;
Zw(end+1) = Zw(end) + Vw(end)*dt;
Ac(end+1) = (1/Mc)*(Cs*(Zw(end)-Zc(end))+Ds*(Vw(end)-Vc(end))+Fs(end));
Vc(end+1) = Vc(end) + Ac(end)*dt;
Zc(end+1) = Zc(end) + Vc(end)*dt;
t(end+1) = t(end) + dt;
else
Zr = 0;
Aw(end+1) = (1/Mw)*(-(Cw+Cs)*Zw(end) + Cs*Zc(end) + Ds*(Vc(end) - Vw(end)) + Cw*Zr(end)-Fs(end));
Vw(end+1) = Vw(end) + Aw(end)*dt;
Zw(end+1) = Zw(end) + Vw(end)*dt;
Ac(end+1) = (1/Mc)*(Cs*(Zw(end)-Zc(end))+Ds*(Vw(end)-Vc(end))+Fs(end));
Vc(end+1) = Vc(end) + Ac(end)*dt;
Zc(end+1) = Zc(end) + Vc(end)*dt;
t(end+1) = t(end) + dt;
end
end
plot(t,Zc)
  2 件のコメント
Chris
Chris 2022 年 12 月 2 日
No problem :)

サインインしてコメントする。

カテゴリ

Find more on View and Analyze Simulation Results in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by