Quantifying infant physical interactions using sensorized toys in a natural play environment

Abstract

Infants with developmental delays must be detected early in their development to minimize the progression of motor and neurological impairments. Our objective is to quantify how sensorized toys in a natural play environment can promote infant-toy physical interactions. We created a hanging elephant toy, equipped with an inertial measurement unit (IMU), a pressure transducer, and multiple feedback sensors, to be a hand-grasping toy. We used a 3 DoF robotic model with inputs from the IMU to calculate multiple kinematic metrics and an equation to calculate haptic metrics from the pressure transducer. Six typical infants were tested in the gym set-up. Three infants interacted with the toy for more than half the trial time. The youngest infant exhibited the largest toy displacement with ΔD = 27.6 cm, while the oldest infant squeezed the toy with the largest mean pressure of 4.5 kPa. More data on on both typical and atypical infants needs to be collected. After testing atypical infants in the SmarToyGym set-up, we will be able to identify interaction metrics that differentiate atypical and typical infants.

Figures

Fig. 1.

An infant in the toy gym set-up. The video system and sensorized mat with its four pressure sensors in the corners are labeled.

Fig. 2.

The three hanging toys inside the toy gym

Fig. 3.

A side-by-side figure of the hanging elephant toy model on the left and the real toy on the right. The model is labeled with the important toy components.

Fig. 4.

The 3 DoF RRR toy model used to measure toy position

Fig. 5.

Toy displacement magnitude graphs as measured in the gym base frame. The digital signals represent left (black) and right (gray) reaches.

Fig. 6.

An xy-excursion plot for Infant 2, T1 with a fitted ellipse around the data, to show that the ellipses capture infant excursion on the xy-plane rather than the density of the points. The other infant fitted ellipses are also displayed. The x- and y-axes roughly represent the size of the mat.

Fig. 7.

Pressure vs. Time plots for each trial. The black horizontal line in each plot represents atmospheric pressure (equal to 101.325 kPa).