1. Four Bar Linkage in Exercise Equipment
Group C
Robert “SolidEdge” Desjardins
Stephanie Louttit
Mark Szymanski
Christopher “GUI” Wirz

2. Overview Four Bars in Exercise Equipment Elliptical Gait Grashof & DOF
SolidEdge Simulation
Instant Centers
MATLab Simulation
Varying Parameters

3. Four Bars in exercise machines!

4. Four Bars in exercise machines!

5. Four Bars in exercise machines!

6. Elliptical Exerciser - Classification
r1 + r2 < r3 + r4
Grashof Class I Kinematic Chain
Crank-Rocker r2

7. Elliptical Exerciser - DOF
J1 = 4
DOF = 3(L – 1) – 2(J1) –J2
DOF = 3(4 – 1) – 2(4)
DOF = 1 d 4 1 a c 2 3 b

8. Elliptical Exercisers
A combination of a stair climber and a cross-country ski machine that you stand on and pedal
No impact
Less likely to injure joints than on a treadmill
Lower perceived exertion for equivalent workout intensity

9. Walking/Running When walking, feet naturally follow path of ellipse
While foot 1 is flat on the ground, foot 2 is in the air moving parallel to the ground
When running, feet pound (impulse) on the ground potentially causing joint injury

10. Elliptical
Elliptical exercisers eliminate impact with the ground by following the natural motion of the feet

11. Elliptical Exerciser SolidEdge Simulation

12. Elliptical Exerciser SolidEdge Simulation

13. Elliptical Exerciser SolidEdge Simulation – Velocity Plots

14. Instant Centers

15. Elliptical Exerciser MATLab Simulation
Matlab GUI for elliptical.zip

16. Normal “Standard” “Plebian”
This is the motion profile for the elliptical machine

17. Varying Parameters r1 r2 r3 r4 r5 t1 t5
Normal 50 8 33 34 12 40
167
Model 5 60
180
Vince 16
Arnold
220
Bush 47
145
Krovi
200
But then we got the celebrities to try out our new elliptical machines!

18. Model

19. Vince Vaughn

20. Arnold Schwarzenegger

21. President Bush

22. Dr. Venkat Krovi

23. Conclusions
Most elliptical exercisers are not adjustable for different heights and stride lengths of people
By varying r2, the stride length can be tuned to different criterion
Further research could be performed in changing the shape of the foot path
for example: from elliptical to figure eight

24. Questions