An experimental study on flowrate and stability of a type of control valve of 600MW supercritical steam-turbine was presented by measuring instruments of static, dynamic pressure and vibration in self-designed test ri...An experimental study on flowrate and stability of a type of control valve of 600MW supercritical steam-turbine was presented by measuring instruments of static, dynamic pressure and vibration in self-designed test rig. The investigation shows that flow coefficient is 30% up more than that of the control valve of GX-1 type used widely in domestic power plants now, as small-medium lifts. If the relative lift (h/D) is less than 20%, the valve can always work steadily in all the pressure ratios. When the h/D is between 20% to 24%, big vibration of valve stem occurs if the pressure ratio is between 0.7 to 0.8. When h/D is more than 25%, relatively great vibration happens in a wide range of pressure ratios of 0.4 to 0.85.展开更多
The dynamic parameters of a roller rig vary as the adhesion level changes.The change in dynamics parameters needs to be analysed to estimate the adhesion level.One of these parameters is noise emanating from wheel–ra...The dynamic parameters of a roller rig vary as the adhesion level changes.The change in dynamics parameters needs to be analysed to estimate the adhesion level.One of these parameters is noise emanating from wheel–rail interaction.Most previous wheel–rail noise analysis has been conducted to mitigate those noises.However,in this paper,the noise is analysed to estimate the adhesion condition at the wheel–rail contact interface in combination with the other methodologies applied for this purpose.The adhesion level changes with changes in operational and environmental factors.To accurately estimate the adhesion level,the influence of those factors is included in this study.The testing and verification of the methodology required an accurate test prototype of the roller rig.In general,such testing and verification involve complex experimental works required by the intricate nature of the adhesion process and the integration of the different subsystems(i.e.controller,traction,braking).To this end,a new reduced-scale roller rig is developed to study the adhesion between wheel and rail roller contact.The various stages involved in the development of such a complex mechatronics system are described in this paper.Furthermore,the proposed brake control system was validated using the test rig under various adhesion conditions.The results indicate that the proposed brake controller has achieved a shorter stopping distance as compared to the conventional brake controller,and the brake control algorithm was able to maintain the operational condition even at the abrupt changes in adhesion condition.展开更多
The performance of any fuzzy logic controller (FLC) is greatly dependent on its inference rules. In most cases, the closed-loop control performance and stability are enhanced if more rules are added to the rule base o...The performance of any fuzzy logic controller (FLC) is greatly dependent on its inference rules. In most cases, the closed-loop control performance and stability are enhanced if more rules are added to the rule base of the FLC. However, a large set of rules requires more on-line computational time and more parameters need to be adjusted. In this paper, a robust PD-type FLC is driven for a class of MIMO second order nonlin- ear systems with application to robotic manipulators. The rule base consists of only four rules per each de- gree of freedom (DOF). The approach implements fuzzy partition to the state variables based on Lyapunov synthesis. The resulting control law is stable and able to exploit the dynamic variables of the system in a lin- guistic manner. The presented methodology enables the designer to systematically derive the rule base of the control. Furthermore, the controller is decoupled and the procedure is simplified leading to a computationally efficient FLC. The methodology is model free approach and does not require any information about the sys- tem nonlinearities, uncertainties, time varying parameters, etc. Here, we present experimental results for the following controllers: the conventional PD controller, computed torque controller (CTC), sliding mode con- troller (SMC) and the proposed FLC. The four controllers are tested and compared with respect to ease of design, implementation, and performance of the closed-loop system. Results show that the proposed FLC has outperformed the other controllers.展开更多
基金This work was supported by National Natural Science Foundations of China (No503360501,50323001)
文摘An experimental study on flowrate and stability of a type of control valve of 600MW supercritical steam-turbine was presented by measuring instruments of static, dynamic pressure and vibration in self-designed test rig. The investigation shows that flow coefficient is 30% up more than that of the control valve of GX-1 type used widely in domestic power plants now, as small-medium lifts. If the relative lift (h/D) is less than 20%, the valve can always work steadily in all the pressure ratios. When the h/D is between 20% to 24%, big vibration of valve stem occurs if the pressure ratio is between 0.7 to 0.8. When h/D is more than 25%, relatively great vibration happens in a wide range of pressure ratios of 0.4 to 0.85.
基金The authors greatly appreciate the financial support from the Rail Manufacturing Cooperative Research Centre(funded jointly by participating rail organisations and the Australian Federal Government’s Business Cooperative Research Centres Programme)through Project R1.7.1–“Estimation of adhesion conditions between wheels and rails for the development of advanced braking control systems”.
文摘The dynamic parameters of a roller rig vary as the adhesion level changes.The change in dynamics parameters needs to be analysed to estimate the adhesion level.One of these parameters is noise emanating from wheel–rail interaction.Most previous wheel–rail noise analysis has been conducted to mitigate those noises.However,in this paper,the noise is analysed to estimate the adhesion condition at the wheel–rail contact interface in combination with the other methodologies applied for this purpose.The adhesion level changes with changes in operational and environmental factors.To accurately estimate the adhesion level,the influence of those factors is included in this study.The testing and verification of the methodology required an accurate test prototype of the roller rig.In general,such testing and verification involve complex experimental works required by the intricate nature of the adhesion process and the integration of the different subsystems(i.e.controller,traction,braking).To this end,a new reduced-scale roller rig is developed to study the adhesion between wheel and rail roller contact.The various stages involved in the development of such a complex mechatronics system are described in this paper.Furthermore,the proposed brake control system was validated using the test rig under various adhesion conditions.The results indicate that the proposed brake controller has achieved a shorter stopping distance as compared to the conventional brake controller,and the brake control algorithm was able to maintain the operational condition even at the abrupt changes in adhesion condition.
文摘The performance of any fuzzy logic controller (FLC) is greatly dependent on its inference rules. In most cases, the closed-loop control performance and stability are enhanced if more rules are added to the rule base of the FLC. However, a large set of rules requires more on-line computational time and more parameters need to be adjusted. In this paper, a robust PD-type FLC is driven for a class of MIMO second order nonlin- ear systems with application to robotic manipulators. The rule base consists of only four rules per each de- gree of freedom (DOF). The approach implements fuzzy partition to the state variables based on Lyapunov synthesis. The resulting control law is stable and able to exploit the dynamic variables of the system in a lin- guistic manner. The presented methodology enables the designer to systematically derive the rule base of the control. Furthermore, the controller is decoupled and the procedure is simplified leading to a computationally efficient FLC. The methodology is model free approach and does not require any information about the sys- tem nonlinearities, uncertainties, time varying parameters, etc. Here, we present experimental results for the following controllers: the conventional PD controller, computed torque controller (CTC), sliding mode con- troller (SMC) and the proposed FLC. The four controllers are tested and compared with respect to ease of design, implementation, and performance of the closed-loop system. Results show that the proposed FLC has outperformed the other controllers.
