Kinematics Flashcards
1
Q
Rigid bodies have…
A
6 DOF
2
Q
Complete kinematic description of a segment is comprised of
A
- position
- linear velocities & accelerations
- angle of segment in 2 planes (defines direction)
- angular velocites and acc
3
Q
Electro-goniometers
A
direct measurement
measure joint angle during motion using potentiometer sensing element
4
Q
Adv of gonio
A
- inexpensive
- immediate output signal available
- recorded planar rotation independent of plane of movement of joint
5
Q
Disadv of gonio
A
- angular data is relative not absolute
- requires time to fit & align
- fit & alignment over muscle and fat may change during motion
- complex gonios required for joints that don’t act as hinges
6
Q
Accelerometer
A
direct measurement
measures linear acceleration (force transducer then F = ma)
7
Q
What are the 3 main types of accelerometer?
A
strain gauge, piezoresistive and piezoelectric
8
Q
Adv of accelerometer
A
Output signal available immediately
9
Q
Disadv of accelerometer
A
- acc relative to position on limb
- can be sensitive to shocks
- mass may give rise to artefacts
10
Q
Motion-capture
A
indirect measurement
records position of markers attached to moving subjects
