Safety experiments for small robots investigating the potential of soft materials in mitigating the harm to the head due to impacts

Abstract

There is a growing interest in social robots to be considered in the therapy of children with autism due to their effectiveness in improving the outcomes. However, children on the spectrum exhibit challenging behaviors that need to be considered when designing robots for them. A child could involuntarily throw a small social robot during meltdown and that could hit another person's head and cause harm (e.g. concussion). In this paper, the application of soft materials is investigated for its potential in attenuating head's linear acceleration upon impact. The thickness and storage modulus of three different soft materials were considered as the control factors while the noise factor was the impact velocity. The design of experiments was based on Taguchi method. A total of 27 experiments were conducted on a developed dummy head setup that reports the linear acceleration of the head. ANOVA tests were performed to analyze the data. The findings showed that the control factors are not statistically significant in attenuating the response. The optimal values of the control factors were identified using the signal-to-noise (S/N) ratio optimization technique. Confirmation runs at the optimal parameters (i.e. thickness of 3 mm and 5 mm) showed a better response as compared to other conditions. Designers of social robots should consider the application of soft materials to their designs as it help in reducing the potential harm to the head.

Influence of the shape and mass of a small robot when thrown to a dummy human head

“…This was more evident at higher impact velocities. This finding combined with our earlier findings of the application of soft materials could provide a better overall reduction in the potential harm [7]. Therefore, the designers of small social robots or robotic toys for special needs children, or even for neurotypical children, should try to minimize the mass of their products as much as possible while adding a layer of a suitable soft material.…”

“…Finally, the peak head acceleration for each experiment was calculated based on a MATLAB script. More detailed procedures can be found in our earlier studies [2,4,6,7].…”

“…The impact setup has been shown to give similar results to that of related studies. More indepth details about the experimental setup and validation can be found in our earlier studies [2,4,6,7]. Fig.…”

“…The method was developed in 1979 and was meant to be used as an off-line quality control tool to improve manufacturing products and goods [45]. Furthermore, it has been considered in different applications [7,27,34,46]. Taguchi DOE considers two types of variables, namely controllable and noise (or uncontrollable).…”

Adaptive threshold for robot manipulator collision detection using fuzzy system

“…The coexistence and interaction of human in the robot workspace are not suitable in many of the existing robotics applications, particularly the robot manipulators for several reasons. One of the most significant reasons is the safety factor [3][4][5][6].…”