Rocking Motion of the Baby Sleeping on the Mother's Lap: Modeling and Prototype Automatic Swing Cradle Design

Abstract

The main purpose of this study is to overcome the difficulties experienced by the mothers during the sleeping period of the babies and to put the babies to sleep in a comfortable and peaceful way as if the babies were in the mother's lap. In this direction, the motion that the mother made while sleeping her baby on the lap was modeled, and a cradle designed to repeat mother movements based on this model. In the modeling phase, 10 subjects were experimented. A doll was given to the subjects and it was requested that to perform a baby rocking motion on their lap for 10 seconds. The performed motions of the subjects were recorded with accelerometer of the mobile phone placed on the doll via an application (Accelerometer Analyser) compatible with the Android operating system. From the acceleration data, the motion trajectories of each subject were achieved through MATLAB. For this aim, firstly the noise in the data was filtered with moving average filter and then trapezoidal integration was applied twice to the filtered acceleration data. After that, the ideal route for the rocking motion on the lap was reached in consideration of the trajectories of the subjects. The mathematical model of the ideal route was derived by least square curve fitting method and the cradle following the mathematical model was designed in Solidworks environment. At the end of the study a prototype cradle was produced.