Chapter 9: Controls Flashcards
1
Q
Two Principles for Discrete Controls- Attention
A
- Proximity compatibility- LIke controls close together
- Avoide resource competition- Avoid simultanous controls to same resource (Right hand, voice)
2
Q
Four Principles of Discrete Controls- Perception
A
- Make accessible- Easily reached/identifable
- Make discriminable- Know the difference between controls
- Exploit redundancy gain- Create redundancy in the difference (color, shape)
- Avoid avsolute judgement limits- 5-7 controls differentiated by code
3
Q
Two Principles of Discrete Controls- Memory
A
- Knowledge in the World- Actuation of control should be reflected in control itself
- Be consistent- Standardize controls within a system, and between systems
4
Q
Two Principles of Discrete Controls- Mental Model
A
- Location compatibility- Control should be close to entity being controlled or display
- Movement compatibiltiy- Control movement should match display or object movement
5
Q
Two Principles of Discrete Controls- Response Selection
A
- Avoid accidental activation
- Hick-Hyman Law- Speed of action selection influenced by number of possible alternatives (Morse Code)
- Decision complexity advantage- More efficient to require smaller number of complex decisions than many simple ones
- Fitts law- Movemenet time depends on distance and target size
- Provide feedback- Transicent feedback (click), and persistent feedback (light)
6
Q
Three levels of position control
A
- Position (Zero-order)
- Velocity (First-order)
- Acceleration (Second-order)
7
Q
Ways to combat closed loop stability
A
- Lower the gain
- Reduce lags and delays
- Caution operator to not correct every input
- Change strategy to seek input that can anticipate and predict
- Change strategy to open loop
8
Q
Difference between open and closed loop system
A
Closed loops required feedback and monitoring performance relative to ideal.
Open loop are ‘ballistic’, in that they are not monitored after activation.
