Problem Set-1b Week 11Challenge : Basic Handling parameters
Wf = 1900; %lb
Wr = 1552; %lb
l = 100.6 ;%in
l = 100.6/12;
%Ackermann steer angles at 500,200,50 ft radius
del500 = l/500*180/pi
del200 = l/200*180/pi
del50 = l/50*180/pi
%weight on each wheel
Wf_one = Wf/2; %950
Wr_one = Wr/2; %776
% finding Calpha for front and rear using interpolation method
Calpha_f = 225 + (950-900)*((257-225)/(1125-900));
Calpha_r = 171 + (776-675)*((225-171)/(900-675));
K = (Wf_one/Calpha_f) - (Wr_one/Calpha_r) %understeer gradient deg/g
% Characteristic speed
Vchar = sqrt((57.3*l*32.2)/(0.1183));%ft/sec
Vchar= Vchar*0.9113444153 %kmph
%lateral acceleration gain at 60mph
V = 88 ; %ft/sec
lat_acc = (((V^2)/(57.3*l*32.2))/(1+((K*V^2)/(57.3*l*32.2)))) %g/deg
%yaw velocity gain at 60mph
yaw_gain = (((V)/(l))/(1+((K*V^2)/(57.3*l*32.2)))) %deg/sec/deg
%Sideslip angle at CG on an 800ft radiusturn at 60mph
b = Wf*l/(Wf+Wr); %distance of CG from rear axle
R = 800; %ft
%since weight on the rear axle is 1552
Calpha_rear = 257+(1552-1125)*((300-257)/(1350-1125));
Sideslip_Angle = (57.3*b/R ) - (1552*V^2)/(Calpha_rear*R*32.2)
%The understeer gradient is low because there are many parameters which
%effects the understeer, here we have only considered only cornering
%stiffness.
Results:
del500 =
0.9607
del200 =
2.4016
del50 =
9.6066
K =
0.1183
Vchar =
329.5367
lat_acc =
0.4727
yaw_gain =
9.9102
Sideslip_Angle =
-1.0474