- GRASPING: Holding an object (it moves with me but is relatively still)
- MANIPULATION: Hold an object and control its trajectory (specific to the object)
We can see:
- Manipulation → active motion
- Grasping → passive motion
→ To manipulate objects humans have specifically developed the thumb
- Really important when talking about manipulation.
There are 2 kinds of manipulation:
Brain prospective
From our brain prospective when we grasp an object (power grasp) it does not cast anything (it doesn’t think about the hand receptors).
- For power grasping we do have control over the object in our hand, but it is not accurate, tho it is fast to process (for our brain).
- For in-hand manipulation, like writing with a pen we use 3 contact point (more generally a small number of contact points) and we need to control each of them very well. (While for power grasping we have many contact point but no need to control them)