CPSC 875 John D. McGregor C 8 More Design

Blackboard style

Blackboard Violates several architecture principles Shared memory Used when fast access to lots of data is needed to make a decision Robotics Situational awareness Perhaps automated driving

Feedback/Control Loop Controller Actuator Sensor Process

State machine architecture Reactive systems Each input determines a state

Design operator: Composition Controller Actuator Sensor Process

Add human controller Controller Actuator Sensor Process

Hazards Car uses old value for set point that causes sudden acceleration Car does not disengage CC when commanded …

lecture-notes/MIT16_63JF12_Class10STPA.pdf

Engine off Engine on CC off CC On Set current speed Maintain current speed Inactive speed set initial timerElapsed apply brake resume engage Resume [setSpeed – currentSpeed< 5mph]/accelerate State machine Recalculate pedal position

Syntax of state diagram EventName [guard]/action SetActive [speed>20mph]/set speed MaintainSpeed[setPoint-current>3mph]/calculate pedal angle SetIdle[]/no op

Cruise control

Adaptive CC control4.htm control4.htm

ACC state machine

Controller OR

CACC les/publications/PRR pdf les/publications/PRR pdf

resources rorModelDiscussion pdf rorModelDiscussion pdf ter/bugtrack-emv2/issue41/Isolette.aadl ter/bugtrack-emv2/issue41/Isolette.aadl 14/SE_67_AVSI-Redman- ConsistencyCheckingInSAVI.pdf 14/SE_67_AVSI-Redman- ConsistencyCheckingInSAVI.pdf fetyAnalysiswithEMV2-july2013.pdf fetyAnalysiswithEMV2-july2013.pdf

RDAL requirements

Context

DARWIN

Darwin Service Space

Prototyping

Next Steps Develop an AADL model of the adaptive cruise control (ACC). Make the feedback loop(s) explicit in your design. Include identified hazards, related requirements, and the AADL design should incorporate those requirements and a complete error model. Submit by 11:59PM Feb 16th

State machine