The purpose of using life extending control for Black Hawk UH-60 helicopter is to make a trade-off between the handling qualities and the service life of critical components. An increase in service life span results i...The purpose of using life extending control for Black Hawk UH-60 helicopter is to make a trade-off between the handling qualities and the service life of critical components. An increase in service life span results in enhanced safety and the reduction in maintenance costs. This paper presents a design methodology of life extending control for structural durability and high performance of mechanical system, which is based on an explicit dynamic inversion control scheme. A real-time nonlinear fatigue crack growth model is built to predict fatigue damage resulting from the impact of cyclic bending stress on rotor shaft, which serves as an indicator of service life. The 4-axis gainscheduled flight controller, whose gains are adjusted as a function of damage and flight velocity, is designed to regulate roll attitude, pitch attitude, vertical velocity and yaw rate. The nonlinear system simulation results show that the responses can meet the requirements on ADS-33 Level 1 handling qualities and that the 4-axis decoupling control is realized. As the damage increases, the tracking performance is slightly degraded, which results in smaller transients in bending moment response.展开更多
In addition to being environmentally friendly,remanufactured products are popular with consumers because they offer the latest technology at a lower price,in comparison to brand new products.However,some consumers hes...In addition to being environmentally friendly,remanufactured products are popular with consumers because they offer the latest technology at a lower price,in comparison to brand new products.However,some consumers hesitate to buy remanufactured products because they are skeptical about their quality.Thus,they are unsure of the extent to which the product will render services when compared to a new product.A promotional marketing strategy employed by remanufacturers is to offer warranties for these products.To that end,this study scrutinizes the impact of offering non-renewing warranties on remanufactured products.Specifically,in this paper,a methodology is suggested,which simultaneously minimizes the cost incurred by the remanufacturers and maximizes consumer confidence toward buying remanufactured products.This study uses a discrete-event simulation to optimize the implementation of a two-dimensional non-renewing warranty policy for remanufactured products.The implementation is illustrated using a specific product recovery system called the Advanced Remanufacturing-To-Order system.The experiments in the study were designed using Taguchi’s Orthogonal Arrays to represent the entire domain of the recovery system to observe system behavior under various experimental conditions.展开更多
基金Supported by the National Natural Science Foundation of China(No.61170328)
文摘The purpose of using life extending control for Black Hawk UH-60 helicopter is to make a trade-off between the handling qualities and the service life of critical components. An increase in service life span results in enhanced safety and the reduction in maintenance costs. This paper presents a design methodology of life extending control for structural durability and high performance of mechanical system, which is based on an explicit dynamic inversion control scheme. A real-time nonlinear fatigue crack growth model is built to predict fatigue damage resulting from the impact of cyclic bending stress on rotor shaft, which serves as an indicator of service life. The 4-axis gainscheduled flight controller, whose gains are adjusted as a function of damage and flight velocity, is designed to regulate roll attitude, pitch attitude, vertical velocity and yaw rate. The nonlinear system simulation results show that the responses can meet the requirements on ADS-33 Level 1 handling qualities and that the 4-axis decoupling control is realized. As the damage increases, the tracking performance is slightly degraded, which results in smaller transients in bending moment response.
文摘In addition to being environmentally friendly,remanufactured products are popular with consumers because they offer the latest technology at a lower price,in comparison to brand new products.However,some consumers hesitate to buy remanufactured products because they are skeptical about their quality.Thus,they are unsure of the extent to which the product will render services when compared to a new product.A promotional marketing strategy employed by remanufacturers is to offer warranties for these products.To that end,this study scrutinizes the impact of offering non-renewing warranties on remanufactured products.Specifically,in this paper,a methodology is suggested,which simultaneously minimizes the cost incurred by the remanufacturers and maximizes consumer confidence toward buying remanufactured products.This study uses a discrete-event simulation to optimize the implementation of a two-dimensional non-renewing warranty policy for remanufactured products.The implementation is illustrated using a specific product recovery system called the Advanced Remanufacturing-To-Order system.The experiments in the study were designed using Taguchi’s Orthogonal Arrays to represent the entire domain of the recovery system to observe system behavior under various experimental conditions.
