Research On Immersive Virtual Maintenance Assessment Method Without Force-feedback

The traditional maintenance assessment relies mainly on the physical prototype of the equipment and a large number of test samples.To some extent,there are some shortcomings such as poor timeliness,high cost and high safety risks.With the development of computer graphics and virtual reality technology,the immersive virtual maintenance evaluation method based on digital prototype can produce realistic simulations similar to the physical test,reduce the requirements on physical objects and actual test environment greatly,and has become a trend of maintainability assessment technology.However,due to the constraints of force-feedback technology,it is difficult to reflect the impact of maintenance loads on human body movement and maintenance process during immersive virtual maintenance tests,resulting in insufficient maintenance accuracy.To this end,this paper mainly studies the immersive virtual maintenance assessment technology under the condition of powerless feedback.The main research work includes:(1)Based on the review of the status of equipment maintenance evaluation and immersive virtual maintenance technology,the impact of lack of force-feedback on immersive virtual maintainability assessment is analyzed,and the technical route for multi-stage comprehensive assessment of maintainability by immersive virtual maintenance approach is made.The qualitative and quantitative system of maintainability indexes is analyzed,and an immersive virtual maintenance test environment was established.(2)Based on the biomechanical model of human musculoskeletal system,the principle of motion and muscle force of human bone-joint system is analyzed,and the Lagrange dynamics method was used to calculate the muscle torque of simplified upper limb model.On this basis,the biomechanical modeling and the calculation of the corresponding joint trajectory of the upper limb handling action in the maintenance process were carried out,and the similarities and differences among the real action,the tester’s action in virtual maintenance test and the biomechanical reconstructed action under multiple maintenance loads were compared.Finally,a method for correcting the motion error of forceless feedback based on polynomial fitting was proposed.(3)Aiming at the multi-source evaluating information existing in the immersive virtual maintenance test,a virtual and real information fusion method based on compatibility test was proposed.On this basis,a multi-stage sequential fusion maintainability evaluation method based on Bayes theory was proposed,which can effectively integrate the immersive virtual maintenance information of each experimental stage and the on-site experimental evaluation information.The calculation for the normal-inverse gamma distribution and its super parameters was carried out,and the average repair time index was taken as an example to verify the simulation.(4)Taking the maintenance of the heat exchanger of TBD-234V6 diesel engine system as an example,the action modification method studied is applied to compensate the maintenance action of the virtual person in immersive virtual maintenance environment.Then the fusion evaluation method studied is applied to carry out a final evaluation of the maintenance index of the heat exchanger,which proves the correctness and effectiveness of the proposed methods,and lays good foundation for the practical application in the actual equipment.