Product development with sensor integrating machine elements – Managing uncertainty associ-ated to in-situ acquired sensor data in mechatronic systems
In the context of the advancing digitalization of mechanical engineering, new innovative concepts for sensor integration are being developed in the scope of current research. These include the so-called sensing machine elements (SME), which enable in-situ measurements directly in the process. At the Institute for Product Development and Machine Elements (pmd) at Technical University of Darmstadt, one research focus is currently on the sensory utilization of rolling bearings. By measuring the electrical impedance of a rolling bearing during operation and using suitable evaluation models, it is possible to record process and condition information, such as speed, bearing load or bearing damage, directly in the process. The use of SME promises, among other things, low integration costs due to the use of already integrated and standardized machine elements and reduced uncertainty due to high process proximity.
In order to be able to implement SME, the sensor elements must be supplied with required energy and the generated sensor signals must be conducted from the sensor element to the evaluation unit. Due to the deep integration into the higher-level technical system and often a placement on rotating elements such as shafts and the requirement to carry out as few design changes as possible, so-called structure-integrated energy and signal paths (sEuSL) are a possible solution, see Figure 1. With these, the required energy as well as the electrical signals are routed via the existing machine structure. These electrical paths are usually not distinct and associated with a high degree of uncertainty due to leakage currents or disturbance variables.
Within the framework of the project funded by the German Research Foundation (DFG) between May 2020 and April 2023 with the title “Product development with sensor integrating machine elements – Managing uncertainty associated to in-situ acquired sensor data in mechatronic systems” and with the project number 431606807, the aforementioned sEuSL as well as the disturbance variables acting on them are to be described quantitatively in order to reduce the uncertainty in this context.
In doing so, the project will investigate the following three topics:
- Identification and quantification of the disturbance influences on the structure-integrated energy and signal paths when sensing machine elements (SME) are integrated into mechatronic systems
- Development of models and methods for the analysis of mechatronic systems with SME for the quantitative evaluation of the disturbance influences
- Development of design guidelines for sEuSL to reduce the susceptibility to disturbances
The procedure within the project is divided into six work packages. In work packages 1 to 3, which are characterized by experiments, the electrical properties of machine elements are investigated and quantitatively modelled as a function of mechanical variables such as force, torque and speed. Based on this, work package 4 identifies and quantitatively describes external disturbance influences on the electrical properties of machine elements under consideration. In the final work packages 5 and 6, the findings will be evaluated in a complete system. Furthermore, these work packages will develop and initially validate suitable methods and design guidelines for subsequent application.