Methodology and application on load monitoring using strain-gauged bolts in brake calipers
2022-01-1121
03/29/2022
- Event
- Content
- As technology evolves, the number of sensors and available data on vehicles grow exponentially. In this context, it is essential to use sensors for monitoring key components, increasing safety and reliability, and gathering data useful for mechanical dimensioning and control systems. This paper presents an application of strain-gauged bolts brake calipers fixation of two electric vehicles. With this approach it was possible to obtain the loads applied to the brake pads and correlate them with braking behavior, therefore gaining insights on braking conditions and system state. The goal of the study is analyzing the strengths and limitations of the method and proposing developments to deploy it in real applications. This topic is particularly important and novel for electric vehicles, where powertrains can create positive and negative torques and generate complex interactions with braking system. Strain-gauges are a long-known technology applied in many fields, and its usage in bolts and screws is well established. However, the automotive field lacks actual use for load sensing and monitoring. The application shows promising results and proves a valid option for monitoring safety components due to its low cost, small dimensions, and reliability. The presented case study takes place in a straight-line test track, where three braking maneuvers were performed: low-pressure braking, mid-pressure braking, and emergence braking. The effects of ABS intervention and wet disk conditions were investigated from an experimental point of view. The paper describes the method used for the strain-gauge application in the bolts, calibration in a dynamometer traction and compression test, installation in the vehicle, and data analysis and post-processing. Results present consistent readings in the higher-pressure conditions, while low-pressure cases show less conclusive outcomes in the current setup. Finally, evolutions of the system and further investigations on this promising technology applied to the automotive field are presented.
- Citation
- de Carvalho Pinheiro, H., Sisca, L., Carello, M., Ferraris, A. et al., "Methodology and application on load monitoring using strain-gauged bolts in brake calipers," SAE Technical Paper 2022-01-1121, 2022, .