Anti-Lock Braking System

1
Anti-Lock Braking System

• ABS1
• Presenter Josh Walworth
• Demo Given by Ryan Stephenson

2
Unique Feature Partitions

• Two distinct functional divisions
• Suggested by specifications
• Manifested in diagrams and prototype
• Components
• Vehicle
• Anti-Lock Braking System

3
What do partitions provide?

• Advantages of partitioned structure
• Simplifies the models
• Encourages cohesion
• Highlights any misinterpreted requirements
• When ABS hardware fails, this division ensures
  that normal braking still occurs.

4
Key Model Class Diagram

• Two levels of aggregation form abstract
  foundation for requirements analysis
• Why class diagram is key
• Developed first
• Implies dynamic component interactions
• Connection to problem domain
• Structure for OO solution design
• Relatively Simple

5
Model
6
Critical Properties

• 1. ABS braking state will eventually be exited
• Liveness
• (stateabsbrake -gt ltgt state!absbrake)
• 2. ABS braking will never disable normal braking
  (ie. during a failure)
• Safety
• (!systemTestPassed -gt ltgt statenormalbrake)

7
Promela and XSpin

• Results of analysis
• LTL formulas input to XSpin
• Exhaustive checking
• Both properties reported valid
• Property 1 This is good news
• Property 2 Must go through reset (not feasible)

8
Demo of Prototype

• High-level features of User Interface
• Condition Settings (to provide road and
  independent wheel slip information)
• Vehicle Action Buttons/Sliders (to start the car,
  accelerate, and brake)
• Readouts (providing speed and braking
  information)

9
Scenario(s)

• 3 Scenarios will be run through normal road
  conditions, icy conditions, and wet conditions.
• 1) Set Conditions
• 2) Accelerate to top speed
• 3) Apply Brakes
• 4) View Results