| The development trend of modern vessels has raised the demands for the steering gear system in small space occupation and low energy consumption and noise.In addition,since vessels often encounter various complex and special(such as heavy underwater load shock)working environments when navigating in the water,the higher demands are proposed on the viability and dynamic characteristics of the vessel's steering gear at the same time.To this end,researchers are constantly seeking ways to improve the viability of the steering gear in special operating environments and its dynamic characteristics from various aspects.The direct drive volume control flange-type rotary vane steering gear(DDVC-FRVSG)is characterized by small volume and low energy consumption,especially its flange-type structure has powerful shock resistance performance.However,the adverse effect of the shock-resistant structure on the dynamic characteristics of the steering gear makes it difficult to track the desired rudder angle commands quickly,accurately and stably,which seriously limits its application on real ships.Through the research conducted by this paper,based on the quantitative design of the shock-resistant structure of the flange-type rotary vane steering gear,the difficulty in describing the dynamic characteristics of the steering gear for the shock-resistant flexible structures was solved by establishing a DDVC-FRVSG,and the complex nonlinear control of the rigid-flexible coupling of the steering gear system was also solved by designing the corresponding control strategy.It is of great theoretical and practical significance for improving the shock resistance and improving the dynamic characteristics of the vessel's steering gear to enhance the maneuvering performance of the vessels.It studied the structure and shock resistance characteristics of the flange-type rotary vane steering gear,designed and optimized the shock-resistance flexible structures,and proposed the mathematical model and simulation verification program of the shock system.Also,it designed the key parameters of the shock-resistance flexible structures with the external shock of heavy underwater load as the background environment.A shock system model describing the shock process of the rotary vane steering gear was developed for its shock resistance response,and the validity of the designed parameters is verified by simulation.The structural parameters were optimized for the contradiction between the shock resistance and the dynamic performance of the steering gear.After the simulation of the finite element model,it was verified that the structural parameters obtained by the optimized design can work properly in the given external shock environment of heavy underwater load while taking into account the dynamic characteristics of the steering gear.This paper studied the nonlinear problems in the control system of steering gear,and established a mathematical model of the steering gear system containing friction and rigid-flexible coupling problems as well as its impact on the dynamic characteristics.The mathematical model of the steering gear system was established with the infinite great rigidity,and on the basis of the analysis on the system stability,the LuGre friction model for the rotary vane steering gear was proposed for the first time for the inherent nonlinear friction problem of the steering gear,which solved the problem that the friction phenomenon of the rotary vane steering gear was difficult to describe.In addition,this paper also analyzed the process in which the rigid-flexible coupling problem of the flange-type rotary vane steering gear affects the dynamic characteristics of the steering gear in detail,and proposed the rigid-flexible coupling mathematical model of the flange-type rotary vane steering gear for the first time,which solved the problem that it is difficult to describe the impact of the shock-resistance flexible structure of this type of steering gear on the dynamic characteristics of the system.By establishing a theoretical model,this paper studied the influence of the rigid-flexible coupling problem of the steering gear on the dynamic characteristics of the system through simulation,and compared the established AMESim model for simulation to verify the correctness and rationality of the rigid-flexible coupling mathematical model.A hybrid control strategy was proposed to solve the nonlinear problem in the control of steering gear for the nonlinear friction of the proposed system and the impact of rigid-flexible coupling on the dynamic characteristics of the steering gear,so as to improve the dynamic characteristics of the system.This paper designed an adaptive robust controller to suppress the inherent nonlinear friction problem of the steering gear system.The system is decomposed into a slow-varying subsystem and a fast-varying subsystem by the method of singular perturbation decomposition to reduce the order of the system.A hybrid control method was designed to improve the adverse impact of the rigid-flexible coupling of the steering gear system on the dynamic characteristics.The two are superimposed to form a new hybrid control strategy.This paper,by theoretical model simulation,verfied the effectiveness of the designe control methods,and verified the validity and rationality of the theoretical model simulation by using AMESim model simulation.In order to verify the effectiveness of the control strategy,this paper uses the existing direct-drive volume-controlled steering gear prototype with electro-hydraulic servo in the laboratory to build a proof-of-principle experimental platform equivalent to the DDVC-FRVSG.This paper,based on the experimental mode of proof-of-principle,conducted experimental verification for the suppression strategy of the nonlinear friction and rigid-flexible coupling hybrid control strategy for the steering gear system respectively.It is proved that the control method proposed in this paper can effectively improve the dynamic characteristics of DDVC-FRVSG system by analyzing the experimental results.Based on the design and optimization of the key structural parameters that affect the shock resistance of the volume control flange-type rotary vane steering gear(DDVC-FRVSG)and by taking full account into the influence of non-linear factors,such as inherent friction and rigid-flexible coupling of the system and those caused by shock-resistance flexible structure,on the dynamic characteristics of DDVC-FRVSG,this paper presents the modeling method and hybrid control strategy for addressing nonlinear problems.This effectively improves the dynamic characteristics of the DDVC-FRVSG system and the design results all have been verified through simulation and experiments.This research is of great theoretical and practical significances to the application of DDVC-FRVSG in complicated and special working environment,and provides the basis for further research in the future,offering important reference value. |
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