In order to improve the shift quality, a linear quadratic optimal tracking control algorithm for automatic transmission shift process is proposed. The dynamic equations of the shift process are derived using a Lagrang...In order to improve the shift quality, a linear quadratic optimal tracking control algorithm for automatic transmission shift process is proposed. The dynamic equations of the shift process are derived using a Lagrange method. And a powertrain model is built in the Matlab/Simulink and veri- fied by the measurements. Considering the shift jerk and friction loss during the shift process, the tracking trajectories of the turbine speed and output shaft speed are defined. Furthermore, the linear quadratic optimal tracking control performance index is proposed. Based on the Pontryagin＇ s mini- mum principle, the optimal control law of the shift process is presented. Finally, the simulation study of the 1 - 2 upshift process under different load conditions is carried out with the powertrain model. The simulation results demonstrate that the shift jerk and friction loss can be significantly re- duced by applying the proposed optimal tracking control method.展开更多
In order to diagnose gear shifting process in automated manual transmission（AMT）,a semi-quantitative signed directed graph（SDG）model is applied.Mathematical models are built by analysis of the power train dynamic ...In order to diagnose gear shifting process in automated manual transmission（AMT）,a semi-quantitative signed directed graph（SDG）model is applied.Mathematical models are built by analysis of the power train dynamic and the gear shifting control process.The SDG model is built based on related priori knowledge.By calculating the fuzzy membership degree of each compatible passway and its possible fault source,we get the possibilities of failure for each possible fault source.We begin with the nodes with the maximum possibility of failure in order to find the failed part.The diagnosis example shows that it is feasible to use the semi-quantitative SDG model for fault diagnosis of the gear shifting process in AMT.展开更多
Gaussian Process Regression (GPR) can be applied to the problem of estimating a spatially-varying field on a regular grid, based on noisy observations made at irregular positions. In cases where the field has a weak t...Gaussian Process Regression (GPR) can be applied to the problem of estimating a spatially-varying field on a regular grid, based on noisy observations made at irregular positions. In cases where the field has a weak time dependence, one may desire to estimate the present-time value of the field using a time window of data that rolls forward as new data become available, leading to a sequence of solution updates. We introduce “rolling GPR” (or moving window GPR) and present a procedure for implementing that is more computationally efficient than solving the full GPR problem at each update. Furthermore, regime shifts (sudden large changes in the field) can be detected by monitoring the change in posterior covariance of the predicted data during the updates, and their detrimental effect is mitigated by shortening the time window as the variance rises, and then decreasing it as it falls (but within prior bounds). A set of numerical experiments is provided that demonstrates the viability of the procedure.展开更多
红外热成像测温是及时发现电缆附件异常发热缺陷的重要方法,但面对海量巡检图像,传统的人工诊断方式费时费力,且过分依赖人工经验。已有研究中为了实现电气设备红外图像的智能诊断,大多提取特定特征量作为所搭建神经网络模型的输入,而...红外热成像测温是及时发现电缆附件异常发热缺陷的重要方法,但面对海量巡检图像,传统的人工诊断方式费时费力,且过分依赖人工经验。已有研究中为了实现电气设备红外图像的智能诊断,大多提取特定特征量作为所搭建神经网络模型的输入,而所提取的特征量也依赖于人工选择。为此,提出了一种基于Faster RCNN(faster regions with convolutional neural networks features)与Mean-Shift的电缆附件缺陷红外图像自动诊断方法。该方法首先基于Faster RCNN网络实现诊断对象的识别定位;之后利用Mean-Shift聚类算法提取过热区域;最后计算温度参数,并根据相应诊断标准得到诊断结果。利用实际巡检图像进行测试,结果表明:所提方法能够在不同拍摄角度、不同背景下准确定位诊断目标与过热区域,继而实现过热缺陷的自动诊断。研究对于实际工程中电缆附件的缺陷诊断具有一定的参考价值。展开更多
基金Supported by the National Natural Science Foundation of China(51475043)
文摘In order to improve the shift quality, a linear quadratic optimal tracking control algorithm for automatic transmission shift process is proposed. The dynamic equations of the shift process are derived using a Lagrange method. And a powertrain model is built in the Matlab/Simulink and veri- fied by the measurements. Considering the shift jerk and friction loss during the shift process, the tracking trajectories of the turbine speed and output shaft speed are defined. Furthermore, the linear quadratic optimal tracking control performance index is proposed. Based on the Pontryagin＇ s mini- mum principle, the optimal control law of the shift process is presented. Finally, the simulation study of the 1 - 2 upshift process under different load conditions is carried out with the powertrain model. The simulation results demonstrate that the shift jerk and friction loss can be significantly re- duced by applying the proposed optimal tracking control method.
基金Supported by the Basic Research Foundation of Beijing Institute of Technology(20130342035)
文摘In order to diagnose gear shifting process in automated manual transmission（AMT）,a semi-quantitative signed directed graph（SDG）model is applied.Mathematical models are built by analysis of the power train dynamic and the gear shifting control process.The SDG model is built based on related priori knowledge.By calculating the fuzzy membership degree of each compatible passway and its possible fault source,we get the possibilities of failure for each possible fault source.We begin with the nodes with the maximum possibility of failure in order to find the failed part.The diagnosis example shows that it is feasible to use the semi-quantitative SDG model for fault diagnosis of the gear shifting process in AMT.
文摘Gaussian Process Regression (GPR) can be applied to the problem of estimating a spatially-varying field on a regular grid, based on noisy observations made at irregular positions. In cases where the field has a weak time dependence, one may desire to estimate the present-time value of the field using a time window of data that rolls forward as new data become available, leading to a sequence of solution updates. We introduce “rolling GPR” (or moving window GPR) and present a procedure for implementing that is more computationally efficient than solving the full GPR problem at each update. Furthermore, regime shifts (sudden large changes in the field) can be detected by monitoring the change in posterior covariance of the predicted data during the updates, and their detrimental effect is mitigated by shortening the time window as the variance rises, and then decreasing it as it falls (but within prior bounds). A set of numerical experiments is provided that demonstrates the viability of the procedure.
文摘红外热成像测温是及时发现电缆附件异常发热缺陷的重要方法,但面对海量巡检图像,传统的人工诊断方式费时费力,且过分依赖人工经验。已有研究中为了实现电气设备红外图像的智能诊断,大多提取特定特征量作为所搭建神经网络模型的输入,而所提取的特征量也依赖于人工选择。为此,提出了一种基于Faster RCNN(faster regions with convolutional neural networks features)与Mean-Shift的电缆附件缺陷红外图像自动诊断方法。该方法首先基于Faster RCNN网络实现诊断对象的识别定位;之后利用Mean-Shift聚类算法提取过热区域;最后计算温度参数,并根据相应诊断标准得到诊断结果。利用实际巡检图像进行测试,结果表明:所提方法能够在不同拍摄角度、不同背景下准确定位诊断目标与过热区域,继而实现过热缺陷的自动诊断。研究对于实际工程中电缆附件的缺陷诊断具有一定的参考价值。
