Parameter Optimization Of Hatch Mechanism For Airliner

In the design of the hatch door mechanism for airliners, an important goal is tocontrol the movement of the hatch door along the prescribed path. Because of theexistence of machining errors and assembly clearances, the actual path may havesome deviation from the standard path, which will affect the normal work of the hatchdoor mechanism and even lead to some serious problems, e.g. the seal trouble and thejam problem. In order to investigate the influence of design parameters mentionedabove and control the deviation under a proper level, it is necessary to do thesensitivity analysis and optimization of the key parameters of the hatch doormechanism. Moreover, in the design of a complex mechanism such as the hatch doormechanism, domestic designers are more engaged in the phase of simply imitation,experimention, simulation and verification for the given design, but lack of asystematical and effective tool to implement an integrated design process includingparameterized modeling, kinematic and dynamic analysis, sensitivity analysis andparameter/tolerance optimization.The present paper deals with the problems stated above, aiming at the hatch doormechanism of ARJ21-700. Some important achievements are:1. A general kinematic optimization model for holonomic multi-body system isestablished, where the sensitivity analysis is carried out using the directdifferentiation method (DDM) and the finite difference method (FDM)respectively. The feasibility and accuracy of FDM is validated through thecomparison with DDM in an example involving the suspension mechanism ofBoeing747. In addition, the method is applied to the sensitivity analysis of thehatch door mechanism of ARJ21within the whole movement process, and theresult provides a basis for the possible compensation design.2. A size optimization model based on the response surface method (RSM) isformulated. Sampling of the system is obtained by a dynamic solver namedTHUSover, and further used in the construction of the approximate responsesurface model of the objective function, which is the accumulated deviation of the movement path here, with respect to the design variables, i.e. the sizeparameters of the components. This explicit model is solved by the method ofsequential quadratic programming, and result in a high-accuracy amendment ofthe movement path of the hatch door mechanism of ARJ21.3. A bi-level optimization model is proposed to realize size tolerance optimization.The extremum deviation of the movement of the hatch door under the giventolerance configuration is obtained by solution of the inner level of optimizationmodel, and minimization of the extremum deviation is implemented by solutionof the external level of the optimization model with the total tolerance of themechanism system being constrained. This model is implemented to the hatchdoor mechnism of ARJ21, and RSM is also adopted here. The numerical resultshows that both the model and the method are effective. Furthermore, the methodis extended to size tolerance optimization problems of multi-body dynamicmodel with the consideration of clearances, and carried out on the hatch doormechanism of Boeing747and ARJ21respectively.4. Based on the dynamic solver named THUSolver, a package of software dealingwith optimization problem of multi-body system is developed to implement aseries of tasks during the design of the hatch door mechanism of ARJ21,including parameterized modeling, kinematic sensitivity analysis, sizeoptimization and size tolerance optimization. The software gives strong supportto improvement of the design process of the hatch mechanism of ARJ21and evenmore general complex mechanism.