Lec 6 Feedback and Control Theory Flashcards
What is Feed-Forward control?
Following through of an action once initiated. No way to stop or adjust action.
What is Feed-Back control?
Adjusting action during movement to end up with positive result
How do subjects adapt to the force field?
First, subjects arm stiffens in all directions for desired location by co-contracting muscles. Then, from Internal model of the environment, subject will have predicted forces.
What would happen in each situation if robot forces were suddenly removed?
In a stiffen arm, this would allow for subjects arm to be straighter. In a Internal model, subjects prediction of arm force would be wrong and cause error
After robot forces was given and removed, what really happened?
Performance got worse due to feed-forward control (subjects prediction to go through with arm force)
What showed Feed-Forward control in the robot forces?
Evidence of error when force field was turned on or off
What showed Feedback control in the robot forces?
Evidence that subjects eventually got to the reaction of reach by correcting self
What is Impedance control?
Stiffening and loosening control in order to conserve energy against muscle damaging
What type of control is the brain, Feedback or Feed-Forward?
Both
Once adapted, your internal model can be modified. But can it be transferred to different workspaces?
Complexity of model and workspace determines if it can transfer
Feed-Forward Control is also known as” ______-_____ control.”
Open-Loop Control
Feedback Control is also known as “_____-_____ control.”
Closed-Loop Control
Define Feed-forward control.
Prediction of neural commands for desired movement
Define Feedback control.
Knowledge of movement used to make corrections to ensure accurate performance during the movement
What is Negative Feedback? Results of Error
Subtracting output from desired output.
Error is reduces, system is stable
What is Positive Feedback? Results of Error
Adding of actual output from desired output to desired output .
Error grows, system unstable if an error occurs
What is the correlation between gain and Proportional-Derivative Control in Feedback Control?
Gain is how much to correct. To Proportional-Derivative Control, it is best to not aim too low or too high of desired aim
What controls are both Feedback Control?
Active and Passive
What is Active Control?
Systematic vary feedback gains until system behaves appropriately
What is Passive Control?
Feedback gains are present, system runs automatically
What is Impedance Control?
Stiffening and loosening control in order to conserve energy against muscle damaging
When catching a moving object, why is midflight not essential as opposed to initial and final flight?
It is not yet essential to adjust midair, since it is uncertain if adjusting is necessary.
