CAM Design with Non-Linear Force Profile

[Siddhant]

I need to design a CAM composite with a spring for an exoskeleton to aid elderly mobility. However, the problem I face right now is that the CAM I designed provides a linear force profile, i.e., the force varies proportionally with the extension of the leg. How can I delay this force applied so that the force generated acts only after a certain point. Thanks in advance :)

 

[P K Pillai]

More details... a sketch...?