Controlling the sensor properties of smart structures produced by metal forming

Abstract

A rotary swaging process is presented which allows the manufacturing of smart structures by forming hollow shafts and joining sensor elements simultaneously. A reasonable form- and force-fit of the sensor element is required to ensure the desired sensory properties of the structure, such as linearity, long-term stability and repeatability. However, the conjoint forming process is subjected to uncertainty which leads to fluctuations of the sensor loads and the remaining pre-tension forces. In order to increase the adjustability and accuracy of the process, the utilization of the sensor signals for a control approach is investigated. The infeed and the mandrel force are found to be potential control parameters and the possible time slot of an intervention is identified. A first control approach is implemented and shows an improvement in accuracy of around 65% compared to the uncontrolled process.