Science and Engineering » LeggedRobot

h1. Gait Knee

h2. Group members:

* Sæþór, Árni, Aníta og Viktoría

*stance phase* 60%

flexion-extension-flexion

*swing phase* 40%

extension

*initial contact*

extension (-2 to 5°flexion)

-The knee can be hyperextended to -2°

 •This means that the knee has to have a convertible knee joint wich can variate from 4° to -2°

by keeping knee extended we keep stability

*loading response*

flexion (15°)

shock absorption

-The center of gravity changes. The weight is changed to the leg which the individual is going to use. 

•The knee need to handle the weight so the knee does not collapse. 

*mid stance*

5°increased flexion, then extends to 12°flexion

to keep stability

*terminal stance*

completion of extension, then flexion starts again at the end.

*pre swing*

flexion(up to 40°)

to prepare for the swing

*swing*

extension

*else*

* people with prostetics have more knee flexion 

*implementation*

* simple hince joint.

* Power for the motors

>* because the robot is stationary the easiest way is to get the power into the knee is from a power cable.

>* we have to be able to unplugge the power from the knee easily. 

>*must have*

>* hinge joint

> > * 2motors (flexion and extension)

> > * 2 degrees of freedom

>* strong build, must be able to carry weight.

>* easy to remove and put on, same system as with össur.

>* sensor for angular postion (gyro sensor

>* acceleration sensor

>*good to have*

>* rotation in the knee

>* force sensor

> >* there has to be some rotation in the knee, otherwise it would be torque in the joint.

> >* easiest to have the rotation below the knee

Calculations.

Max torque in the knee with a 120kg load at 40° is 405 Nm. So the motor need to handle that kinda torque