Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Architecture Optimisation applied to Gearboxes SIM@SYST. Level 2014, Carg` ese Steven Masfaraud 1 2 Fabrice Danes 1 Pierre-Emmanuel Dumouchel 1 Florian de Vuyst 2 Nicolas Vayatis 2 1 PSA Peugeot Citro¨ en 2 CMLA ENS Cachan October 20, 2014 Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 1 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Architecture optimization of gearboxes 1 Gearbox Architectures Milestones Specifications Criteria, Constraints State of art Optimization of a given architecture 2 Problem definition Framework for optimization of given architecture Formalization of architecture description Analysis: computation of criteria and constraints functions Optimization strategy Concluding remarks 3 Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 2 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Gearbox Architectures Architecture optimization of gearboxes Create a software that find the best gearbox according to some specifications ⇒ Browse all architectures (technical solutions) Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 3 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Gearbox Architectures Architecture optimization of gearboxes Create a software that find the best gearbox according to some specifications ⇒ Browse all architectures (technical solutions) Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 3 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Gearbox Architectures Architecture optimization of gearboxes Create a software that find the best gearbox according to some specifications ⇒ Browse all architectures (technical solutions) Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 3 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Gearbox Architectures Architecture optimization of gearboxes Create a software that find the best gearbox according to some specifications ⇒ Browse all architectures (technical solutions) Components composing an architecture: Rotating shafts Connexions between shafts: Gears, epicyclic, CVT, freewheel... Selection components: synchronizers, clutches... Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 3 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Milestones Milestones Viability tester Architecture Optimizer Results analysis Architecture Generator Test viability: Best representant Valid Parametrization Assemblate blocks Best representant Store best -obtaining ratios Architecture architecture of best Arch representants Optimization to create arch -commandable Invalid architecture Optimization of given architecture to find its best representative 1 Architecture generation 2 Filtering architecture with automated engineer reasoning 3 Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 4 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Milestones Design Space Once the engineer has selected an architecture, he must finds the best dimensions of the gearbox to meet the specifications λ 5 λ 3 λ 4 λ 2 λ 1 λ 6 λ 7 λ 8 λ 9 Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 5 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Specifications Specifications Ratio definition While engaged, a gear defines a ratio of rotational speed between the input (engine) and the output (wheels) r i = ω output , i = [1 , ng ] ω input with n g the number of gears of the gearbox Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 6 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Specifications Specifications Ratio definition While engaged, a gear defines a ratio of rotational speed between the input (engine) and the output (wheels) r i = ω output , i = [1 , ng ] ω input with n g the number of gears of the gearbox Adaptation of gearbox ratios on each couple car/engine Lower CO 2 emissions on certification cycles Maximize the driveability Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 6 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Specifications Specifications Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 6 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Criteria, Constraints Criteria, Constraints Criteria Minimize distance to ratios specifications Minimize mass Minimize production price Maximize efficiency Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 7 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Criteria, Constraints Criteria, Constraints Criteria Minimize distance to ratios specifications Minimize mass Minimize production price Maximize efficiency Constraints Imposed functional volume Non-collision of gearbox parts Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 7 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks State of art State of art: at PSA Constrained optimization for known architecture Parametrize the architecture: position of parts and shafts, diameters of gear Writing on paper the objective function to maximize Writing on paper the (in)equations of constraints Exceeding of functional volume No part collision Writing them in a Matlab input file for optimization Issues Architecture is fixed A change in architecture means rewriting everything from scratch Functional volume must be simple to have analytical equations Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 8 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks State of art State of art: Literature review Yi-shih Lin (2009): A Method and Software Tool for Automated Gearbox Synthesis Associated with Engineers from Romax (Gearbox software editor) Automatic solving of ratios, graph-oriented Volume constraints simplified to 1D problems Set of elementary components limited (only gears) No other work related afterwards, no implementation known in Romax Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 9 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Problem definition Respect of specifications Objective function to maximize i = nr � ( r i ( x ) − r it ) 2 − µ 2 m ( x ) f ( x ) = − µ 1 − µ 3 V ext ( x ) − µ 4 V c ( x ) � �� � i =1 Constraints � �� � Criteria r i ( x ) Actual Ratio r it Targeted Ratio ng Number of gears m ( x ) Actual mass V ext ( x ) Overflow volume of parts outside of functional volume V c ( x ) Collision volume between parts µ 1 , µ 2 Balance coefficients given by the engineer µ 3 , µ 4 Very high penalty coefficients Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 10 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Problem definition Respect of specifications Objective function to maximize i = nr � ( r i ( x ) − r it ) 2 − µ 2 m ( x ) f ( x ) = − µ 1 − µ 3 V ext ( x ) − µ 4 V c ( x ) � �� � i =1 Constraints � �� � Criteria It is possible to imagine configurations that does not respect the constraints Constraints violation= low function value The optimizer can find its way in order to reduce constraints violation Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 10 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Framework for optimization of given architecture Optimization workflow Function Value Parts Catalog Architecture Analyser Optimizer Architecture Models Generator Parameters set up point Volumic Analyser parameters General Mechanics Compute mass, volumes Forces Sizer Compute Speeds Models Forces Volumes Mass Ratios function evaluator Specifications Function Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 11 / 17
Architecture optimization of gearboxes Optimization of a given architecture Concluding remarks Formalization of architecture description Description by a graph Idea Describe in a simple way the technical solution Shafts connected by functions ⇒ graph Mechanical point of view: Energy paths in the gearbox Handle assembly constraints for parametrizing Graph analyser writes geometrical assembly constraints These constraints are solved in a constructive way Steven Masfaraud (PSA/CMLA) Architecture Optimisation of Gearboxes October 20, 2014 12 / 17
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