Current Issue : January - March Volume : 2017 Issue Number : 1 Articles : 5 Articles
With more axles for multi-axle vehicles, conventional steering trapeziums are unable to let every tire fit Ackermann\nsteering which cause tire wear increasingly more serious. To alleviate this problem, an original mechanic-hydraulic servo\nsteering system with a controllable tie rod is designed. By controlling the angle of one wheel and the length of tie rod,\nboth wheels can be controlled as per default trajectory which implemented Ackermann steering. This article utilized\nmechanic-hydraulic servo feedback to design a mechanic-hydraulic servo valve which controlled the tie rod accurately. It\nensured dynamic characteristics of steering wheels and driving force. To understand inherent characteristics of system,\nthe mathematical model was established. The transfer function was derived, and this high-order system was reduced by\nRouth approximation. Analyzed natural frequency and the main parameter (the gain coefficient of displacement) which\ninfluences the dynamic characteristics had been found out. Analysis shows that the lower the gain coefficient, the higher\nthe speed of response. Moreover, the accurate simulation model of servo system is built on AMESim. Contrasting five\ngroups of simulation results, it is obtained that the influence rule of the gain coefficient is consistent with theoretical\nanalysis. This research provides a useful reference for future nonlinear control....
The shaft manufacturing bending deviation occurs frequently in many types of shaft applications, such as crank shaft and\nroller shaft, and this issue will eventually affect the overall dynamic performance of the rotorââ?¬â??shaft-bearing system. In\nthis study, a systematic modeling approach is developed to analyze the effect of shaft manufacturing bending deviation on\nthe dynamic behavior of the geared rotor system. To validate the proposed approach, a practical example of spur geared\nrotor system was used and the shaft manufacturing bending deviation data were measured by a shaft testing bench. The\nwhole system was modeled using a finite element method and the dynamic characteristics of meshing gear pair were\nrepresented by a coupled torsionalââ?¬â??lateral gear dynamic model. Then, the effects of the dynamic gear mesh force, magnitude\nof deviation, position of deviation, and rotating speed on the dynamic responses of the geared rotor system were\nevaluated. The calculation results show that these parameters have different effects on the systematic vibration response\nof the geared rotor system, indicating that the geared rotor system has different dynamic sensitivities to those different\nexcitations. This study helps to get a better understanding of the dynamic behavior of the geared rotor system with shaft\nbending deviation and can provide guidance for quality control of shaft manufacturing process in view of system\ndynamics....
Failure prognosis is the key point of prognostic and health management or condition-based maintenance, the multiple\nuncertainty sources in real world will lead to inaccurate prediction. In this paper, an advanced failure prognosis\nmethod with Kalman filter is presented to address the real-world uncertainties. The multiple uncertainty sources are\nanalyzed and classified first and then theoretical methods are derived, respectively, for the different uncertainty\nsources. Afterward, the failure prognosis algorithm is developed by taking into consideration. In the end, an aircraft\nfuel feeding system health monitoring case simulation is presented to demonstrate the effectiveness of the proposed\nmethod....
Traditional regenerative braking control strategies only consider how to ensure motor to work along with the battery/\nmotor joint high-efficiency working line, but do not consider continuously variable transmission efficiency. However, continuously\nvariable transmission efficiency varies between 70% and 95% which cannot be neglected. Based on the analysis\nof relationship among the battery, motor, continuously variable transmission, and synthesis efficiency, the battery/motor/\ncontinuously variable transmission joint high efficiency is calculated and obtained, and the regenerative braking control\nstrategy is proposed. Comparing the previous control strategy with battery/motor joint high efficiency, the motor average\ngenerating efficiency increases by 2.91%, and braking energy recovery rate increases by 4.09% under Extra Urban\nDriving Cycle, while the motor average generating efficiency increases by 3.84%, and braking energy recovery rate\nincreases by 5.74% under Federal Test Procedure-72 through offline simulation. Furthermore, under the hardware-inthe-\nloop test, the average generating efficiency increases by 2.72%, and the braking energy recovery rate increases by\n5.03% under Extra Urban Driving Cycle, while the average generating efficiency increases by 3.13%, and the braking\nenergy recovery rate increases by 3.94% under Federal Test Procedure-72. Both simulation and hardware-in-the-loop\ntest results show that the proposed regenerative braking control strategy can realize battery, motor, and continuously\nvariable transmission to work with joint high efficiency which can enhance braking energy recovery rate....
Many multi-axle applications use electro-hydraulic control systems with proportional valves. The proportional steering\nsystem can satisfy common engineering requirements, but it is likely to fail if the steering angle or load changes drastically\nbecause of poor dynamic characteristics, including dead zones, hysteresis, and frequency response. An electro-hydraulic\nservo steering system with servo solenoid valve is proposed to guarantee a precise dynamic response and good priceââ?¬â??\nperformance ratio of the closed-loop system. A co-simulation model based on ADAMS and AMESim was established to\nanalyze the influence of the main parameters on steering performance. The mechanical model includes tire and ground\nparts, and the steering load can be simulated accurately. The simulation results show that dead zones, hysteresis, and frequency\nresponse of control valve have great influence on the steering performance, and the servo solenoid valve is\nproper for this system. The servo steering system was applied to the actual seven-axle all-terrain crane, and the system\nperformance was extensively tested. The experiment results show that the system has good accuracy and tracking\nresponse performance in several real situations, including parking and high-speed transport....
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