Anti-Lock Braking System ABS1 Presenter: Josh Walworth Demo Given by: Ryan Stephenson

Unique Feature: Partitions Two distinct functional divisions –Suggested by specifications –Manifested in diagrams and prototype Components: –Vehicle –Anti-Lock Braking System

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.

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

Vehicle ABS Caliper Wheel Controller Sensor PM Model

Critical Properties 1. ABS braking state will eventually be exited Liveness [] (state==absbrake -> <> state!=absbrake) 2. ABS braking will never disable normal braking (ie. during a failure) Safety [] (!systemTestPassed -> <> state==normalbrake)

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)

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)

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