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A nonlinear mapping model of hydraulic pump flow based on prior data was proposed to solve the problems of nonlinear flow and nonlinear load disturbance of hydraulic pump in variable speed electro-hydraulic flow matching system of truck crane. Firstly, the mathematical model of the motor, quantitative pump and hydraulic cylinder was built. Then, the relationship between the pressure, speed and volumetric efficiency of the hydraulic pump was measured through experiments, the volumetric efficiency cloud diagram was fitted, and the pump flow nonlinear mapping model was constructed. Finally, taking the luffing mechanism as the analysis object, the AMESim software was used to build a system simulation model, comparative simulation analysis of hydraulic pump flow nonlinearity and nonlinear load disturbance before and after flow compensation was carried out. The research results show that under the compensation of the hydraulic pump flow nonlinear mapping model, the system can compensate the motor speed, so that the output flow of the hydraulic pump does not change with the change of load pressure, when the load has 25 kN, 50 kN and 75 kN step fluctuations, the maximum flow fluctuation amplitude is reduced by 52.1%, 47.9% and 43.5% respectively, which verifies the effectiveness of the proposed flow nonlinear model and improves the control accuracy and motion stability of the luffing telescopic mechanism. [ABSTRACT FROM AUTHOR]

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Aiming at the problems of high cutting force, fast tool wear and high cutting temperature of 316 stainless steel, improving the ma­chining performance, reducing the cutting force, optimizing cutting parameters and reducing the frictional resistance between the tool and the chip were studied in the research. The frictional test of the tool was researched under the orthogonal cutting parameters by the turning test method. The YW1 carbide tool was used to test the 316 stainless steel bar under dry cutting conditions, and the influence of cutting parame­ters on the friction characteristics between tool and chip was analyzed. Third Wave AdvantEdge finite element software was used to analyze the cutting process. The experiment resules indicate that the influence of three factors of cutting parameters on the friction coefficient, μ, be­tween tool and chip in the dry cutting environment is from large to small in order of feed, cutting speed, back feed. The optimum combination of cutting speed Vc(120 m/min) , feed rate f (0. 2 mnVr) , back feed ap(1 mm) is selected based on the minimum friction coefficient be­tween the tool and the chip. [ABSTRACT FROM AUTHOR]

Aiming at the trajectory tracking control problem in non-minimum phase system, the feedforward controller design method, model-inverse technique and adaptive control of non-minimum phase system were studied based on the closed-loop injection architecture of it. The non-minimum phase ignore(NPZ-Ignore), zero-phase-error tracking control(ZPETC) and zero-amplitude-error tracking control(ZMETC) technology were used to design the system feedforward controller, and the effect was analyzed. Based on it, aiming at the non-minimum phase zero offset in the system, the forgetting factor least squares method was used to realize the feedforward controller’s self-adaptation, and the simulation and experiment were carried out. The results indicate that the feedforward controller designed with ZMETC technology can improve the tracking accuracy of the non-minimum phase system more effectively than the ZPETC technology and the NPZ-Ignore technology. The tracking error is reduced by 61.45% and 56.27%, respectively. The adaptive algorithm can realize adaptive control of system parameter changes and improve the anti-interference performance of the system. [ABSTRACT FROM AUTHOR]

Aiming at the difficulties in parameter setting and weak anti-interference ability in tension control system of warp netting machine, a fuzzy PID control method was applied. The multivariable, nonlinear and time-delay aspects of tension control system were researched. The mathematical model of the warp tension of warp netting machine and the main influencing factors of the tension fluctuation were analyzed. After the membership function and fuzzy control rule table were determined, the conventional PID control and fuzzy control were combined effectively, and the simulations of which were established by Matlab Simulink module. Finally, this control method was applied to winding and unwinding system for testing the function of this control system. The experimental result shows that the method which was based on the fuzzy PID control can improve the response speed and anti-interference of the tension control system, and the steady state can be rapidly restored after being disturbed so as to realize the stable control of the warp netting machine. [ABSTRACT FROM AUTHOR]

Game model is established with mutual relation between enterprise decision and customer behavior included. According to product inventory and pricing decision where demands are uncertain, customer behavior under different price discount was analyzed. Analytical ex­pressions of the optimal inventory，optimal product price, and customer’s choice to different discount were obtained. The properties of equi­librium solution of the game model are further analyzed by two case studies. The result of the study suggests that the game model is beneficial to enterprise with high product price and price discount. This model helps enterprise better deal with customers' rational selection. [ABSTRACT FROM AUTHOR]