Reducing Design Errors in Complex State Machines using Model-Based Design

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1 Reducing Design Errors in Complex State Machines using Model-Based Design s s s Fredrik Håbring Senior Application Engineer Embedded Control Systems 0 The MathWorks, Inc.

2 Finding Errors Late in Project is Costly 60% 60% Where Errors are Introduced and Detected 55% 50% 40% 0% 0% 8% % 5% % 0% % 0% 7% Detected Specification Design Implement Test Introduced each delay in the detection and correction of a design problem makes it an order of magnitude more expensive to fix Clive Maxfield and Kuhoo Goyal EDA: Where Electronics Begins

3 Power Window System Test and Verification on Prototype

4 Power Window System Test and Verification using Models Switches Armature Current + - V Up s s Down V- V+ s Up Down Control System H-Bridge DC Motor Mechanism State machine (high complexity) 4

5 Test Coverage Analysis for Models Coverage from first simulation Coverage from second simulation Total coverage Decision coverage Condition coverage MC/DC Lookup table coverage Signal range coverage Supported coverage types 5

6 6 Many parts not sufficiently tested Full coverage desirable Not covered Decision Coverage MC/DC Coverage When to Stop Testing? Measuring Coverage

7 Degree of automation Map of Testing Methods Test Generation Metrics covering structure Structural Coverage Metrics Test Generation Autom. covering Analysis requirements Reqs Coverage (test case independant) Formalized Requirements Legend Test Generation Random Test (Monte Carlo) Test generation with env. constraints Abstract Checks Test Analysis Test Metrics Recorded Tests from previous test drives Regression Test (expected values) Test Man. Design Review (each test run) (manual) Relevance for requirements 7

8 Power Window System Requirement Example Whenever an obstacle is detected, the down command shall be given for second. 8

9 Power Window System Formalized Requirement Example and EndStop is not pressed 9

10 TRW Automotive Develops and Tests Electric Parking Brake Using Simulink and Simulink Design Verifier Challenge Design tests for an electric parking brake control system Solution Use Simulink Design Verifier to automatically generate tests that maximize model coverage and enable systematic design verification Results Test development time reduced from days to hours 00 percent model coverage achieved Formal testing begun two months into the project Link to user story Electronic parking brake control system. Everyone knows that errors are much less expensive to fix when you find them early. With Simulink Design Verifier, we build on the advantages of Model-Based Design by performing formal testing in the first phases of development." Christoph Hellwig TRW 0

11 Automatic Code Generation and Verification Reducing Efforts in Going from Design to Implementation REQUIREMENTS DESIGN TEST & VERIFICATION IMPLEMENTATION C, C++ VHDL, Verilog Structured Text MCU DSP FPGA ASIC PLC, PAC

12 Automatic Code Generation and Verification Reducing Efforts in Going from Design to Implementation REQUIREMENTS DESIGN TEST & VERIFICATION IMPLEMENTATION C, C++ MCU DSP C/C++ code verification using Processor-in-the-Loop (PIL)

13 Serial Automatic Code Generation and Verification Processor-in-the-Loop (PIL) Verification Simulink Test Signals Controller Model Verifications Embedded Processor Serial Code Generation C/C++ Code PIL Implementation

14 Wärtsilä Automates Production Code Generation for Large Industrial Embedded Systems Challenge Develop embedded controls for large diesel and gas engines that lower emissions and increase performance and reliability Solution Use MathWorks tools for Model-Based Design to design, test, and automatically generate embedded code for innovative controller algorithms Results Reusable models 0% faster code 00-00% increase in productivity Link to user story Modern control features are notoriously problematic to develop and often involve extensive engine testing. Simulink and Embedded Coder let us design and optimize the features early in our process, saving a large amount of costly engine tests. Wärtsilä engine. Johan Pensar Wärtsilä 4

15 Benefits of Model-Based Design Models: Core of the Development Process Unambiguous Description of Requirements (Executable Specification) Executable Specifications Fast Evaluation of Design Variants Frontloading - Early Test and Verification Automatic Code Generation Design with Simulation Models Continuous Test and Verification Better Cooperation, Communication and Collaboration Automatic Code Generation Higher Product Quality 5