Xie Xiao, Chen Yumin, Li Changchun, Guo Junwei, Sarajpoor Saeed
College of Civil and Transportation Engineering, Hohai University, Nanjing, 210098, China.
Institute for Smart City of Chongqing University in Liyang, Liyang, 213300, China.
Sci Rep. 2023 Nov 23;13(1):20585. doi: 10.1038/s41598-023-47400-5.
Traffic sign poles are crucial components of the highway system, and their maintenance mainly relies on the subjective judgment of staff, which is low-efficiency and will lead to mistaken inspections. This paper proposes a convenient and effective method to monitor the health of sign poles by using a mobile phone. It is unknown whether a mobile phone can be used as a conventional acceleration sensor. Therefore, the performance of the mobile phone was initially tested to ensure its suitability for acquiring the acceleration data of the traffic sign pole. The results show that the acceleration sensor of mobile phones is high-performance and can be used as a traditional acceleration sensor under the similar sampling frequency. The mobile phone can measure the 1st, 2nd and 5th natural frequencies of the traffic sign pole. Although the 1st and 5th natural frequencies have a large error with simulation, the 2nd natural frequency is accurate and stable. The looseness of the base connection greatly impacts on the 2nd natural frequency, which can be used as a measure of the loose base connection. The 2nd natural frequency was measured for 21 times and found to conform to a normal distribution. The relationship between the 2nd natural frequency and base connection loosening was investigated, which fitted to the equation. The fitting result is good and can be used to predict the degree of sign pole base connection loosening. Therefore, the mobile phone based convenient health monitoring method for traffic sign poles is feasible.
交通标志杆是公路系统的关键部件，其维护主要依赖工作人员的主观判断，效率低下且会导致检查失误。本文提出一种利用手机监测标志杆健康状况的便捷有效方法。手机是否能作为传统加速度传感器尚不清楚。因此，首先对手机性能进行测试，以确保其适用于获取交通标志杆的加速度数据。结果表明，手机加速度传感器性能良好，在相似采样频率下可作为传统加速度传感器使用。手机能测量交通标志杆的一阶、二阶和五阶固有频率。虽然一阶和五阶固有频率与模拟结果有较大误差，但二阶固有频率准确且稳定。底座连接松动对二阶固有频率影响很大，可将二阶固有频率作为衡量底座连接松动的指标。对二阶固有频率进行了21次测量，发现其符合正态分布。研究了二阶固有频率与底座连接松动之间的关系，并拟合出方程。拟合效果良好，可用于预测标志杆底座连接松动程度。因此，基于手机的交通标志杆便捷健康监测方法是可行的。
