Week 1 Flashcards
What are the two empirical observations? Describe them in short?
Fitt’s Law - If you need accuracy you become slow.
Movement and accuracy are inversely related
Two-Third Power Law - If you are making a curved movement you become slow. Curvature and velocity have a proportional relationship.
Define space in terms of Motor control? Example
Set of points with some added structure eg Plane: two dimensional space
Two types of space in motor control?
End effector
Configuration
Define coordinate system in terms of motor control?
Set of numbers (coordinates) that uniquely determine a point in space
Two types of Coordinate systems?
Egocentric - coordinate system attached to body
Allocentric - coordinate system attached to object or external world
What is Coordinate transformations? What are the two types?
Moving from one system to another
Forwards kinematics - Configuration to end effector space
Inverse kinematics - end effector to configuration space
What is dynamics/kinetics ?
Forces and torques required for specific movements of objects
Two types of dynamics / kinetics ?
Forward - Kinetics to kinematics
Inverse - kinematics to kinetics
What is kinematics ?
What is the resultant movement of the objects aftershock torques/forces are applied
What is kinematics ?
What is the resultant movement of the objects aftershock torques/forces are applied
Newton’s second law? In relation to Kinematics
Kinematics to Kinetics
Force = Mass x Acceleration
F = MA
Force = Dynamics
Mass = Inertia
Acceleration = kinematics
What are the two control strategies ?
Feedforward (pre planned)
Feedback (adaptive)
Variability in movement?
Even repetitive movements show variability, reflecting the underlying strategies and uncertainties in brain control.
+ and – of Feedforward (open loop)?
+ =
Speed - no info to be processed
Determinism - clear plan actions proceed with no interruption
–=
Error accumulation - any error in initial plan can add up, leading to deviations
Inflexibility - changes and the unexpected cannot be accommodated
High cost - requires effort beforehand
+ and – of feedback (closed loop)?
+=
Flexibility - can adapt to changes
Robustness - error can be corrected during execution preventing them adding up
Generality - Strategies can be applied to wide range of tasks and conditions
– =
Time - processing feedback can slow down actions
Instability - noisy signals and reliance on them can lead to instability
Reliance on quality - if incorrect or inconsistent task may not be executed correctly
