Peer-to-Peer Ultra-Wideband Localization for Hands-Free Control of a Human-Guided Smart Stroller.

We propose a hands-free control system for a human-guided smart stroller. The proposed method uses real-time peer-to-peer localization technology of the human and stroller to realize an intuitive hands-free control system based on the relative position between the human and the stroller. The control method is also based on functional and mechanical safety to ensure the safety of the stroller's occupant (child) and the pilot (parent) during locomotion. In this paper, first, we present a preliminary investigation of the humans' preference for the relative position in the context of hands-free guided strollers. Then, we present the control method and a prototype implemented with an electric wheelchair and UWB sensors for localization. We present an experimental evaluation of the proposed method with 14 persons walking with the developed prototype to investigate the usability and soundness of the proposed method compared to a remote joystick and manual operation. The evaluation experiments were conducted in an indoor environment and revealed that the proposed method matches the performance of joystick control but does not perform as well as manual operation. Notably, for female participants, the proposed method significantly surpasses joystick performance and achieves parity with manual operation, which shows its efficacy and potential for a smart stroller. Also, the results revealed that the proposed method significantly decreased the user's physical load compared to the manual operation. We present discussions on the controllability, usability, task load, and safety features of the proposed method, and conclude this work with a summary assessment.

Optimal low-cost cooling strategies for infant strollers during hot weather.

The current study aimed to identity the optimal low-cost stroller cooling strategies for use in hot and moderately humid summer weather. A commercially available stroller was instrumented to assess the key parameters of the thermal environment. The cooling efficacy of eight different stroller configurations was examined in a counterbalanced order across 16 hot summer days (air temperature (Ta) = 33.3 ± 4.1 °C; relative humidity = 36.7 ± 15%; black globe temperature = 43.9 ± 4.6 °C). Compared with a standard-practice stroller configuration, combining a moist muslin draping with a battery-operated clip-on fan provided optimal in-stroller cooling, reducing the end-trial air temperature by 4.7 °C and the wet bulb globe temperature (WBGT) by 1.4 °C. In contrast, in-stroller temperatures were substantially increased by draping a dry muslin (Ta = +2.6 °C; WBGT = +0.9 °C) or flannelette (Ta = +3.7 °C; WBGT = +1.4 °C) cloth over the stroller carriage. These findings provide empirical evidence which may inform guidance aimed at protecting infants during hot weather.Practitioner summary: This study examined the efficacy of traditional and novel stroller cooling strategies for use in hot and moderately humid weather. Covering the carriage with a dry muslin cloth substantially increased stroller temperatures and should be avoided. Evaporative cooling methods reduced in-stroller temperatures. A moist muslin cloth draping combined with a fan provided optimal stroller cooling.

Convective heat transfer coefficient relating to evaluation of thermal environment of infant.

Infants have a low capacity to thermally adapt to their environment and so sufficient consideration must be given to their thermal environment. In investigating an infant's thermal environment, the purpose of this study is to clarify the heat transfer coefficient in natural convection for the posture of an infant in a stroller. The heat transfer coefficients were measured by means of using a thermal manikin. The experimental thermal environment conditions were set for eight cases, at: 16 °C, 18 °C, 20 °C, 22 °C, 24 °C, 26 °C, 28 °C, and 30 °C, and the air and wall surface temperatures were equalized, creating a homogeneous thermal environment. The air velocity (less than 0.2 m/s) and relative humidity (50%RH) were the same for each case. The surface temperature of each part of the thermal manikin was controlled to 34 °C. The difference between the mean surface temperature and air temperature (ΔT [K]) is the driving force for the heat transfer coefficient in natural convection for the posture of an infant in a stroller (hc [W/(m2·K)]). We propose the use of the empirical formula hc = 2.16 ΔT 0 .23. The formula of the convective heat transfer coefficient in natural convection of this study can be applied to infants up to about 3 years old.

Hip Spica Stroller: A Technical Note.

Background: Care of the child after hip-spica application is the most challenging issue faced by parents. Reduced mobility and recumbency can cause respiratory problems, skin irritation and discomfort for the child. Parents need to lift the child in a spica to make him upright and to mobilize. To improve the comfort of the family in post spica care, we have designed a 'Hip Spica Stroller' which is low profile, comfortable, easy to construct and relatively inexpensive. This manuscript discusses our early experience with this hip-spica stroller use. Methods: A sturdy, relatively lightweight and portable stroller was designed in collaboration with local mechanical engineering team. The stroller allowed safe upright placement of the child with spica and their easy mobility. From the second post-operative day, children were mobilised in the stroller. We looked for development of any complications related to the stroller such as spica breakage, skin irritation or excoriation development. Parents were also inquired about their feedback and satisfaction with the device upon spica removal. Results: We used the spica stroller in nine patients after Developmental Dysplasia Hip (DDH) treatment and in eight patients post shaft femur fracture treatment. None of the patients experienced any stroller-related complications. All the patients maintained the joint reduction and the fractured bone fragment alignment. High satisfaction rates were reported by parents. Conclusion: Hip Spica Stroller is an innovative and easy-to-make device which would enhance the post spica care. It can aid alleviating the fear of parents for their child's hip-spica treatment. Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-021-00568-2.

The modularization design and autonomous motion control of a new baby stroller.

The increasing number of newborns has stimulated the infant market. In particular, the baby stroller, serving as an important life partner for both babies and parents, has attracted more attention from society. Stroller design and functionality are of vital importance to babies' physiological and psychological health as well as brain development. Therefore, in this paper, we propose a modularization design method for the novel four-wheeled baby stroller based on the KANO model to ensure the mechanical safety and involve more functionalities. Manual control of the baby stroller requires the rapid response of human motor systems in a completely controlled manner, which could be a potential risk. To enhance the safety and stability of the stroller motion, especially in situations where manual control is hard to achieve (e.g., sharp turns), we propose an autonomous motion control scheme based on model predictive control. Both the modularization design and the motion controller are verified in the MATLAB simulation environment through path tracking tasks. The feasibility is validated by the satisfactory experimental results with lateral position error in a reasonable range and good trajectory smoothness.

Run kinematics with and without a jogging stroller.

BACKGROUND: Jogging strollers have become increasingly popular as they allow a parent the freedom to run without having to leave their children. Few studies have examined the effects of running with a stroller and no study to date has examined the effects on joint kinematics. The aim of this study was to compare lower limb and trunk kinematics while running with and without a jogging stroller. METHODS: Participants (N=15) ran on a 16-metre indoor runway, with and without a stroller, at their self-selected comfortable training speed. Three-dimensional trunk and lower limb kinematics were assessed using the CODA cx1 active marker system. FINDINGS: The jogging stroller led to reduced movement of the trunk in both the transverse [mean difference -11.4°, 95% confidence interval (CI) (-14.8°, -8.2°), p<0.001] and coronal [-2.9°, 95% CI (-0.8°, -4.9°), p=0.009] planes most likely due to fixing of the upper limbs. There was also a 6.7° [95% CI (-9°, -4.6°), p<0.001] increase in forward trunk lean, 2.8° [95% CI (-4.2°, -1.7°), p<0.001] increase in anterior pelvic tilt and a 3° [95% CI (-4.4°, -1.5°), p=0.001] decrease in hip extension. There were no significant changes in knee or ankle kinematics and no changes in stride length, cadence or stance time. INTERPRETATION: Our data suggest that jogging strollers lead to minor changes in trunk, pelvis and hip kinematics with no significant changes at the knee and ankle. Due to the changes in kinematics we suggest that flexibility work for the spine, pelvis and hips may be recommended.