Comfort of children in cycle carriers

Abstract: Carriers attached as bicycle trailers that can transport small children are becoming increasingly popular in recent years. They replace cars as a convenient and sustainable way to travel for families in commuting and other everyday activities. However, research into the level of whole-body vibration experienced by children in this type of vehicle is very limited, with none conducted in laboratory conditions. Prolonged exposure to high levels of vibration can cause discomfort and even lead to health concerns. In this thesis project a test-bed is designed to perform controllable and repeatable measurements. Various load and tyre pressure conditions are used to study their impact on the vibration level. Sinusoidal inputs are used to excite the carrier, and output responses are measured with accelerometers placed on the surface of the carrier seat. In addition, a basic ADAMS model is built to simulate the same setups as the laboratory measurements. In both methods, the average frequency-weighted acceleration values are found to be much higher than that in passenger cars, reaching an "extremely uncomfortable" level according to ISO 2631-1 standards. It is also observed that tyre pressure has a significant impact on vibration, and its relation with vertical acceleration is non-monotonic. Suggestions for further improvement on the test-bed design and wider use of computer models are made.