碰摩是转子系统中的一种常见故障。针对转子早期碰摩故障特征微弱难以提取的问题,在改进传统动态时间扭曲(Dynamic Time Warping,DTW)算法的基础上,提出一种基于角度权值的动态时间扭曲(Angle Weighted Dynamic Time Warping,AWDTW)算...碰摩是转子系统中的一种常见故障。针对转子早期碰摩故障特征微弱难以提取的问题,在改进传统动态时间扭曲(Dynamic Time Warping,DTW)算法的基础上,提出一种基于角度权值的动态时间扭曲(Angle Weighted Dynamic Time Warping,AWDTW)算法。在该算法中,通过识别不同时间序列的坐标向量之间的夹角,自动计算两时间序列中对应点的距离权值,并通过增加角度权值来改善传统DTW算法的不合理扭曲对齐,以此减少时间序列匹配时“奇点”的产生,从而提高时间序列的对齐精度。通过仿真数据和转子试验台碰摩振动数据来验证所提方法的有效性,同时,与传统DTW及其改进算法相比,所提方法因综合考虑坐标因素的影响,更有利于时间序列的对齐和相似性度量,从而能更有效凸显转子早期碰摩故障特征。展开更多
Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure loss and suitability for large and medium diameter pipelines. Due to control problems res...Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure loss and suitability for large and medium diameter pipelines. Due to control problems resulting from switching angular speeds of the hydraulic butterfly valve, a throttle-governing control mode has been widely adopted, and detailed analysis has been carried out worldwide on the structural principle concerning speed-regulation and the load torque on the shaft while opening or closing a hydraulic butterfly valve. However relevant reports have yet been published on the change law, the error and the influencing factors of the rotational angular velocity of the hydraulic butterfly valve while opening and closing. In this article, research was based on some common specifications of a hydraulic butterfly valve with a symmetrical valve flap existing in a marine environment. The throttle governing system supplied by the accumulator to achieve the switching of the hydraulic control valve was adopted, and the mathematical models of the system were established in the actual conditions while the numerical simulations took place. The simulation results and analysis show that the rotational angular velocity and the error of the hydraulic butterfly valve while switching is influenced greatly by the drainage amount of the accumulator, resulting in pressure loss in the pipeline, the temperature of hydraulic medium and the load of the hydraulic butterfly valve. The simulation results and analysis provide a theoretical basis for the choice of the total capacity of the accumulator and pipeline diameters in a throttle governing system with a hydraulic butterfly valve.It also determines the type and specification of the hydraulic butterfly valve and the design of motion parameters of the transported fluid.展开更多
文摘碰摩是转子系统中的一种常见故障。针对转子早期碰摩故障特征微弱难以提取的问题,在改进传统动态时间扭曲(Dynamic Time Warping,DTW)算法的基础上,提出一种基于角度权值的动态时间扭曲(Angle Weighted Dynamic Time Warping,AWDTW)算法。在该算法中,通过识别不同时间序列的坐标向量之间的夹角,自动计算两时间序列中对应点的距离权值,并通过增加角度权值来改善传统DTW算法的不合理扭曲对齐,以此减少时间序列匹配时“奇点”的产生,从而提高时间序列的对齐精度。通过仿真数据和转子试验台碰摩振动数据来验证所提方法的有效性,同时,与传统DTW及其改进算法相比,所提方法因综合考虑坐标因素的影响,更有利于时间序列的对齐和相似性度量,从而能更有效凸显转子早期碰摩故障特征。
文摘Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure loss and suitability for large and medium diameter pipelines. Due to control problems resulting from switching angular speeds of the hydraulic butterfly valve, a throttle-governing control mode has been widely adopted, and detailed analysis has been carried out worldwide on the structural principle concerning speed-regulation and the load torque on the shaft while opening or closing a hydraulic butterfly valve. However relevant reports have yet been published on the change law, the error and the influencing factors of the rotational angular velocity of the hydraulic butterfly valve while opening and closing. In this article, research was based on some common specifications of a hydraulic butterfly valve with a symmetrical valve flap existing in a marine environment. The throttle governing system supplied by the accumulator to achieve the switching of the hydraulic control valve was adopted, and the mathematical models of the system were established in the actual conditions while the numerical simulations took place. The simulation results and analysis show that the rotational angular velocity and the error of the hydraulic butterfly valve while switching is influenced greatly by the drainage amount of the accumulator, resulting in pressure loss in the pipeline, the temperature of hydraulic medium and the load of the hydraulic butterfly valve. The simulation results and analysis provide a theoretical basis for the choice of the total capacity of the accumulator and pipeline diameters in a throttle governing system with a hydraulic butterfly valve.It also determines the type and specification of the hydraulic butterfly valve and the design of motion parameters of the transported fluid.
