intro to movement planning Flashcards
what is the general rule of Fitt’s law
the more accurate the movement, the slower the movement becomes
briefly describe the two-third power law
when making curved movements, it becomes slower the more curved .
power of curvature is proportional to velocity
what elements does a robot arm need to consider before picking up an apple
localisation and planning
execution and control
adaptation
what is space
set of points with some added structures
if a model has locations labelled through xyz coordinates what type of space is displayed
effector space
task space
operational space
if a model has locations labelled through joint angles what types of space would be displayed
configuration space
joint angle space
body space
what are coordinates
set of numbers that uniquely define numbers in space
what is a coordinate/reference frame
a single space with multiple coordinate systems
cartesian coordinate system
defines 3 points in space
xyz coords
cylindrical coord system
defines how far a point is within one plane
the angle between the direction of the point and the x axis
spherical coordinates system
uses different angles and distances
egocentric coords
System is attached to the body
e.g. POV in vid game
allocentric coords
system is attached to the external world/object
e.g. 3rd person view in vid game
inverse kinematics
end effector space to configuration space
forward kinematics.
configuration space to end effector
what is meant by redundancy in terms of kinematics
kinematics don’t always have a SINGLE solution
finger can be art same point but can have different joint angles
what type of kinematics is redundant
inverse
what is dynamics
kinetics
adding forces to torques
what is linear vs angular kinematics
distance vs angles
what is linear vs angular kinetics
forces vs torques
what is inverse dynamics
kinematics to kinetics
what is forward dynamics
kinetics to kinematics
what equation in terms of newtons second law describes relationship between kinematics and dynamics
force = inertia x acceleration
force and acceleration are vectors of forces and torques
what is a feedforward open loop of control
movement pre planned / pre determined
pros of feedforward loop
movement can be controlled without requiring external info
good for fast movement
cons of feedforward control
errors can accumulate overtime
no flexibility with environment
high cost of planning - no generalisation
what is a feedback closed loop of control
uses feedback from environment to predict/produce movement
pros of feedback control
flexible - deals w unexpected events
robust - control error doesn’t accumulate
general - control is invariant to starting or goal position
cons of feedback control
time consuming
can become unstable if feedback is noisy and when feedback gain is high
can be unstable when feedback is delayed
what is meant by variability
when same movement is repeated, uncertainties can change the movement pattern
insight into brain control strategy
