Projects

Introduction

Nowadays monitoring systems are used in a wide range of applications and different information can be derived, depending on the signal processing. An example is given by the classical fatigue analysis for permanently excited structures (condition monitoring) or static structures (structural health monitoring). Especially in sports, such systems must satisfy stringent requirements like robustness, compactness, weight, and cost-effective implementation. Furthermore, a suitable concept could afford the realization of further ergometric functions. In this case, a monitoring system for a lightweight carbon fiber paddle was designed and implemented.

Design and Implementation

Initially a reference measurement was performed with a paddle instrumented with seven strain gauges. Strain was measured under various conditions using a commercial system. Based on the results a reduced concept was developed. Hereby the special requirements such as weight and waterproofness for kayaking sports were taken into account. The overall system consists of sensors (piezoelectric patches), a central electronic unit for recording dynamic load and a smartphone as a user front-end. The measurement concept is suitable for longterm measurement, wherein a load classification for data reduction is calculated in real time. The monitoring system can be operated without graphical user interface. The overall weight is only 180 grams in this case. Optionally an Android tablet pc or mobile phone can be added to visualize the timedata and classification results. Afterwards laboratory test rigs can apply this measured loads in fatigue tests.

Conclusion

The developed system is suitable for logging the dynamic loads on the kayak paddle in the field. The proposed system is cost-effective and it does not cause any restrictions to the user. The compact, battery-operated system also enables the implementation of additional ergometric functions. By using a modular electronic design and a rapid prototyping case the concept can be adapted easily and flexibly to other applications. For future work it is planned to certify the monitoring system in laboratory and field tests.