Overheating of the engine, the transmission and the hydraulic device is a problem when the construction machinery works on plateau. To solve this problem, we proposed an electro-controlled hydraulic driving fan coolin...Overheating of the engine, the transmission and the hydraulic device is a problem when the construction machinery works on plateau. To solve this problem, we proposed an electro-controlled hydraulic driving fan cooling system (ECHDFCS). The system was applied to a 50-wheel loader. We carried out the coolant temperature simulation using fluid modeling software FLOWMASTER, followed by laboratory experiments and road tests. The results show that ECHDFCS can adjust the cooling capability of the system automatically based on machine heat dissipation requirements. The coolant temperature is consequently remained within an appropriate range. The simulation results are consistent with the experiment results when the experiment is performed on the plain, but are different from the road tests in some investigated parameters on the plateau.展开更多
In mobile machinery,hydro-mechanical pumps are increasingly replaced by electronically controlled pumps to improve the automation level,but diversified control functions(e.g.,power limitation and pressure cut-off)are ...In mobile machinery,hydro-mechanical pumps are increasingly replaced by electronically controlled pumps to improve the automation level,but diversified control functions(e.g.,power limitation and pressure cut-off)are integrated into the electronic controller only from the pump level,leading to the potential instability of the overall system.To solve this problem,a multi-mode electrohydraulic load sensing(MELS)control scheme is proposed especially considering the switching stability from the system level,which includes four working modes of flow control,load sensing,power limitation,and pressure control.Depending on the actual working requirements,the switching rules for the different modes and the switching direction(i.e.,the modes can be switched bilaterally or unilaterally)are defined.The priority of different modes is also defined,from high to low:pressure control,power limitation,load sensing,and flow control.When multiple switching rules are satisfied at the same time,the system switches to the control mode with the highest priority.In addition,the switching stability between flow control and pressure control modes is analyzed,and the controller parameters that guarantee the switching stability are obtained.A comparative study is carried out based on a test rig with a 2-ton hydraulic excavator.The results show that the MELS controller can achieve the control functions of proper flow supplement,power limitation,and pressure cut-off,which has good stability performance when switching between different control modes.This research proposes the MELS control method that realizes the stability of multi-mode switching of the hydraulic system of mobile machinery under different working conditions.展开更多
The paper presents a method of the runner blades design for simple case of hydraulic turbine. Two differently shaped channels of meridional cross section were examined. The quantitative evaluation was performed by mea...The paper presents a method of the runner blades design for simple case of hydraulic turbine. Two differently shaped channels of meridional cross section were examined. The quantitative evaluation was performed by means of 3D algorithm. It has been found that, divergent runner prevails convergent from dissipation point of view. Although, the influence of draft tube has not been analyzed, the presented method is important for the designers of low head hydraulic turbines which are not the matter of standardization due to variety of environmental conditions.展开更多
以电磁作动器式主动液阻悬置为研究对象,建立机-电-磁-液多物理场耦合的力学及数学模型,并推导次级通道传递特性,旨在分析和评估其在抑制车辆振动方面的性能。采用基于电压控制形式的次级通道传递特性的窄带复数滤波最小均方N-C-FxLMS(n...以电磁作动器式主动液阻悬置为研究对象,建立机-电-磁-液多物理场耦合的力学及数学模型,并推导次级通道传递特性,旨在分析和评估其在抑制车辆振动方面的性能。采用基于电压控制形式的次级通道传递特性的窄带复数滤波最小均方N-C-FxLMS(narrowband complex filtered-x least mean square)算法对系统进行仿真,并且基于dSPACE半实物仿真平台和inova振动试验台进行试验验证。仿真结果表明,在25~200 Hz的频段内,所提出的控制策略能够显著改善系统的减振性能。试验结果表明,主动控制能将传递至车身端的振动减小17 dB~27 dB,验证了模型的准确性和控制策略的有效性,为主动悬置系统的设计和优化提供了有价值的理论依据和试验支持。展开更多
基金Funded by the Innovation Foundation of Guangzhou, P. R. China (No. 2005V42C0021)
文摘Overheating of the engine, the transmission and the hydraulic device is a problem when the construction machinery works on plateau. To solve this problem, we proposed an electro-controlled hydraulic driving fan cooling system (ECHDFCS). The system was applied to a 50-wheel loader. We carried out the coolant temperature simulation using fluid modeling software FLOWMASTER, followed by laboratory experiments and road tests. The results show that ECHDFCS can adjust the cooling capability of the system automatically based on machine heat dissipation requirements. The coolant temperature is consequently remained within an appropriate range. The simulation results are consistent with the experiment results when the experiment is performed on the plain, but are different from the road tests in some investigated parameters on the plateau.
基金National Key Research and Development Program of China(Grant No.2020YFB2009702)National Natural Science Foundation of China(Grant Nos.52075055,U21A20124 and 52111530069)Chongqing Natural Science Foundation of China(Grant No.cstc2020jcyj-msxmX0780)。
文摘In mobile machinery,hydro-mechanical pumps are increasingly replaced by electronically controlled pumps to improve the automation level,but diversified control functions(e.g.,power limitation and pressure cut-off)are integrated into the electronic controller only from the pump level,leading to the potential instability of the overall system.To solve this problem,a multi-mode electrohydraulic load sensing(MELS)control scheme is proposed especially considering the switching stability from the system level,which includes four working modes of flow control,load sensing,power limitation,and pressure control.Depending on the actual working requirements,the switching rules for the different modes and the switching direction(i.e.,the modes can be switched bilaterally or unilaterally)are defined.The priority of different modes is also defined,from high to low:pressure control,power limitation,load sensing,and flow control.When multiple switching rules are satisfied at the same time,the system switches to the control mode with the highest priority.In addition,the switching stability between flow control and pressure control modes is analyzed,and the controller parameters that guarantee the switching stability are obtained.A comparative study is carried out based on a test rig with a 2-ton hydraulic excavator.The results show that the MELS controller can achieve the control functions of proper flow supplement,power limitation,and pressure cut-off,which has good stability performance when switching between different control modes.This research proposes the MELS control method that realizes the stability of multi-mode switching of the hydraulic system of mobile machinery under different working conditions.
文摘The paper presents a method of the runner blades design for simple case of hydraulic turbine. Two differently shaped channels of meridional cross section were examined. The quantitative evaluation was performed by means of 3D algorithm. It has been found that, divergent runner prevails convergent from dissipation point of view. Although, the influence of draft tube has not been analyzed, the presented method is important for the designers of low head hydraulic turbines which are not the matter of standardization due to variety of environmental conditions.
文摘以电磁作动器式主动液阻悬置为研究对象,建立机-电-磁-液多物理场耦合的力学及数学模型,并推导次级通道传递特性,旨在分析和评估其在抑制车辆振动方面的性能。采用基于电压控制形式的次级通道传递特性的窄带复数滤波最小均方N-C-FxLMS(narrowband complex filtered-x least mean square)算法对系统进行仿真,并且基于dSPACE半实物仿真平台和inova振动试验台进行试验验证。仿真结果表明,在25~200 Hz的频段内,所提出的控制策略能够显著改善系统的减振性能。试验结果表明,主动控制能将传递至车身端的振动减小17 dB~27 dB,验证了模型的准确性和控制策略的有效性,为主动悬置系统的设计和优化提供了有价值的理论依据和试验支持。
