Institut Supérieur de l Aéronautique et de l Espace Constraints Annex Implementation Approach

Transcription

1 Institut Supérieur de l Aéronautique et de l Espace Constraints Annex Implementation Approach Jérôme Hugues, ISAE/DMIA jerome.hugues@isae.fr

2 Rethinking what we have already > Idea not new, tested in various conditions > True DSL, as AADL annex languages» REAL, since 2008 Offsprings: Lute and Resolute extending/patching syntax» ACCOLL, ISORC 10 paper > Or bound to other languages» Paper from Dio DeNiz, EMSOFT 11 using Mathematica» Fused (S. Vestal et al.): bridge AADL and other tools > Which track to follow for AADL Constraint Language?» Initial design intent was to follow DSL path, but this choice was neither analyzed, nor formally balloted Constraints Annex Implementation Approach page 2

3 REAL > Initial goal to support enforcement of structural constraints at model-level» Defines accessors and computation rules on model elements > E.g. AADLv2 and ARINC653 annex support IMA concepts» Needs to constraint models to respect some invariants theorem scheduling_major_frame -- Check configuration of partition scheduling foreach cpu in processor_set do check ((float (property (cpu, "ARINC653::Module_Major_Frame")) = sum (property (cpu, "ARINC653::Partition_Slots")))); end scheduling_major_frame; system IMA_System extends AADL_System implementation/extension must respect profile annex real_specification {** theorem check_ima foreach s in local_set do requires (check_ima_profile); -- logical conjuction of theorems end check_ima; **}; end IMA_System; Constraints Annex Implementation Approach page 3

4 AADL model elements > REAL uses partial (naïve) AADL meta model Package. Public decl... Private decl. Component type. Identifier. Extends. Prototypes. Features. Flows. Properties. Annex. Ports. Access. Subprogram. Parameter. Feature Category. Data. Subprogram. Thread (group). Process. Memory. Device. (virtual) processor. (virtual) bus. System. Abstract references Property sets. Units. Property type. Property definition. Constants Component implementation. Identifier. Extends. Subcomponents. Connections. Call sequences. Modes. Flows. Properties. Annex Constraints Annex Implementation Approach. Ports. Access. Parameter. Modes. transitions page 4

5 PERSEUS supersonic rocket > Analysis of rocket kinematics performance Similar to constraints: perform computation, and in the end a go/no-go test But needs to drag recursion, complex maths Eventually calls to external tools for solving maths, e.g. for CPS Question: How far should we go in defining this annex? Constraints Annex Implementation Approach page 5

6 UAV/UGV platforms at ISAE (EMS 09 project) > Platforms for ground and flying robots» Semi-autonomous» Variations around captors/actuators, field buses and CPUs > Analysis Test bench done for by AADLv2 reviewing model elements:» Interface consistency behavior of task, energy consumption of devices => E = Σ C» Power consumption dev x Δt Equation attached to the system, evaluated by iterating overs system > Complex architecture, energy validation subcomponents BUT - Scheduling analysis can help refine previous equation EMAXXV2 - Model of CPU (HDL) to refine consumption through behavioral analysis Inertial 3.3V + GPS 3.3V - Physical models of converters US1 USART2 USART1 USART1 USARTx USART2 telemeter 3.3V 1.8V Need more than accessors, analysis (tools) must collaborate! US2 3.3V ARM7 ARM9 TWI(I²C) USART0 USART0 I²C 1.8V USB1 USB2 option CAN ADC µsd 3.3V SDIO AD0 Volt div PWM PWM0 PWM1 TC0 TC1 TC2 TIMERS TC3 TC4 TC5 TC6 TC7 TC8 ETH 3.3V battery battery 14.8V 4000mAh 5.0V Servo (direction) Servo (direction) Motor 2 Motor 1 EVX Titan 550 rc/calc Auto/man assisted Odo Meter 1 direction motor Odo Meter 2 3.3V 5.0V 14.8V 4000mAh ch4 ch3 ch2 ch1 Receiver RC ETHERNET1_bus ETHERNET2_bus ETH ETH ETH Router +Wifi ETH camera GPU 23-march-2010 Constraints Annex Implementation Approach page 6

7 Current design of AADL Constraints Language > Attaching constraints + queries is clear from experiments > Not so clear is computations associated to model entities (11) Component Contract Viewpoints Declaration and Use grammar (10) Assumptions, Guarantees, Composition Facts In Annex subclause (9)Temporal Formulas in Annex subclause (PSL subset) (7) State Sequence Expressions sublanguage grammar (PSL subset) (12) Instance Contract Viewpoints Declaration and Use grammar (8) Theorems in Annex subclause (Lute/Real) (6) Set building sublanguage grammar (Lute/Real) (5) Static scalar Functions/Predicates Declaration and Use grammar rules Attaching constraints to model To be discussed today (4) Built-in Model Traversal Access Functions (3) Relational and Boolean Expressions grammar rules (2) Feature Data Reference grammar (or built-in functions) (Component Types, Subcomponents, Feature groups) Queries on model elements (1) AADL Property Expressions and Constants Constraints Annex Implementation Approach page 7

8 Offered options > Own DSL» Which abstraction for collections of entities? Sets? Lists? Graphs? Which associated API? Semantics? etc» Link with external tools?» Semantics of computations?» Learning curve? Note: REAL performed good on learning (passed some time), but badly on links and abstractions» Has an impact on annex document complexity > Using existing language» Which one? Python?, Java (then use OSATE2 API)? VBA ;)? SQL? Prolog» Pick one that allows for simplified constraints management (learning curve, artifacts,,...)» Large ecosystem + external libraries for computation, etc.» Support for interoperability with other tools, simplified mapping towards third party à-la-qvt Constraints Annex Implementation Approach page 8

9 Words from previous committees > Accessors derive from data model/meta model of AADLv2» From A. Plantec. These are languages #1 to #4 > I miss <insert your strange feature> in REAL (#5 & #6)» From V. Gaudel, G. Duval, and many others > Attaching constraints to model elements but also creating libraries provide great flexibility in analysis/restricting models» From your humble servitor, covers #8 & #12 > Why don t we use Python? By Alexey Actually, most of the discussion is focusing on computational part (#5 & #6), not on theorems or accessors Constraints Annex Implementation Approach page 9

10 Intermediate ballot? Proposal: just like language #7 is PSL (but could be LTL or CTL or <name_it>), we should give the opportunity to tell what language #5 and #6 is left to the designer. Pro: great adaptability to designer s choice Con: dangerous: one needs to address the situation where a language #6 is not understood by a tool. More reasonable proposal: propose a simple DSL for computation like we have in REAL/Lute, etc. Take advantage of the compute keyword facility to open to other tools or languages. Constraints Annex Implementation Approach page 10