ME 581 - Spring 2014 – C05
Name ________________________
1) For a right McPherson strut, attach local coordinate frames to each link for a fixed position of
the steering rack. Clearly label all auxiliary points and vectors needed to form constraints.
2) Write a corresponding set of generalized coordinates q .
3) Symbolically write a constraint vector  for this mechanism using a vertical absolute
translation driver for the strut-spindle assembly at a fixed position of the steering rack.
4) Numerically check the residuals of  using measurements from model hardware.
5) Symbolically write the corresponding Jacobian matrix  q .
6) Numerically evaluate the elements of the Jacobian and compute the determinant of the
Jacobian.
7) Program your constraints and Jacobian into a Newton-Raphson iterative algorithm to solve
position kinematics for any desired vertical translation of the strut-spindle assembly.
8) Plot toe-in versus vertical motion of the strut-spindle assembly.
ME 581 - Spring 2014 – C05
Name ________________________
CHASSIS
MOUNT
1
F
1 = ground
2 = A-arm
3 = strut / cylinder
4 = piston
4
PISTON
ROD
RACK
CYLINDER
TIE
ROD
E4
D
C
E3
3
STRUT
WHEEL
SPINDLE
A
1
B
2
A-ARM
1 = ground
2 = A-arm
3 = strut / cylinder
4 = piston
CHASSIS
MOUNT
1
CHASSIS
MOUNT
ME 581 - Spring 2014 – C05
Name ________________________
y4
F4
F1
CHASSIS
MOUNT
PISTON
ROD
A = revolute (5)
B = sperical (3)
CD = double spherical (1)
E = prismatic (5)
F = spherical (3)
z4
TIE
ROD
x4
D
use double spherical
between C and D
E4
C
CYLINDER
y3
C3
z3
RACK
E3
fixed
steering
angle
D1
STRUT
x3
CHASSIS
MOUNT
WHEEL
SPINDLE
z1
y1
B3
z2
x2
CHASSIS
MOUNT
y2
x1
B2
A2
A-ARM
A1
ME 581 - Spring 2014 – C05
Name ________________________
McPherson strut model - rear view
McPherson strut model - side view
F
y4
F
y4
1 = ground
2 = A-arm
3 = strut / cylinder
4 = piston
z4
x4
E4
E3
E4
y3
1 = ground
2 = A-arm
3 = strut / cylinder
4 = piston
D
y3
x3
C
y2
E3
D
z3
y1
x2
A
x1
B
C
y1
z1
A
B
ME 581 - Spring 2014 – C05
Name ________________________
F
F
26.35 cm
507 pixels
0.05187 cm/ pixel
20.64 cm
541 pixels
0.03815 cm/ pixel
E4
E4
E3
E3
D
C
D
y1
y1
A
x1
C
B
A
z1
B
scaled from photographs on class web page
cm
A
B
C
D
E3
E4
F
x1
0
15.70
15.49
6.03
13.51
13.03
12.06
y1
0
1.40
5.87
6.81
12.16
15.56
22.35
z1
0
0
5.77
4.60
0
0
0