# Study on Relay Contact Bounce Based on the Adaptive Weight Rotation Template Matching Algorithm
## 2 Introduction to the Research Subjects  
The relay studied in this paper is a heavy, elastic, DC, magnetic-type electrodeless relay of a DC 24V series. The contacts of the relay are typical cylindrical contacts. To analyze the process of relay contact bounce through imaging, a high-speed camera was used to capture images of the contact motion during the relay action. The high-speed camera is a Pco.dimax S model high-speed camera developed by KUK, Bad Schonborn, Germany, and the optical lens is an AF-S VR Micro-Nikkor 105 mm f/2.8 G IF-ED from Nikon (Tokyo, Japan). Some of the key parameters of the camera and the optical lens are shown in Tables 1 and 2, respectively. The set camera acquisition frequency is 10,000 frames/s, and the acquired relay images are shown in Figure 1.  
The bounce of relay contacts refers to the phenomenon where the contacts of a relay close and open multiple times in a short period due to mechanical vibrations or the elasticity of the springs during the closing process [23]. In the contact bounce process, the bounce time refers to the duration during which the relay experiences an intermittent disconnection of contacts when closing or an intermittent closure of contacts when opening [24]. The bounce height is the maximum distance over which the contacts open during the contact bounce period [25]. The time required to reach the maximum distance is the duration from the moment the contacts begin to separate until the contacts reach their maximum separation distance.  
For the relay studied in this paper, its structural components are illustrated in Figure 2. When the relay contacts close or open, under the influence of electromagnetic force or gravity, the moving contact and the stationary contact come into contact and move together for a certain distance, exceeding their stable positions. This causes a certain amount of elastic deformation in the reed. When the elastic force generated by the deformation exceeds the electromagnetic force or gravity, it leads to a rebound of the contacts. In this process, the moving contact and the stationary contact vibrate together, and contact bounce typically occurs during this stage.  
\begin{table}
\begin{tabular}{c c} \hline
**Parameter Name** & **Parameter Size** \\ \hline Maximum resolution & 1008 \(\times\) 1008 \\ Maximum frame rate & 152,811 fps \\ Exposure time & 1.5 μs\(\;\)us–40 ms \\ \hline \end{tabular}
\end{table}
Table 1: Key parameters of high-speed camera.  
Figure 1: Relay image acquired by high-speed camera.  
The partial sequence images of a single set of contacts during the relay action process are depicted in Figure 3. Combining these images with the relay's action process, it is evident that the side view of the stationary contact during the relay's action process forms an inclined rectangle. As the relay contacts undergo actions such as attraction and release, the inclination angle of the stationary contact changes accordingly. Calculating the relay contact bounce requires analyzing the position and angle of the stationary contact in the side view image. Therefore, an appropriate recognition algorithm is needed that can accurately select the position and edges of the stationary contact while obtaining its inclination angle.