Fig 2 - uploaded by Masayoshi Wada
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The spherical power transmission mechanism of ACROBAT consists of two balls. It consists of two layers, Part A and Part B roughly.
Source publication
In this paper, we present motion analysis and prototype design of a new omni-directional wheel mechanism "ACROBAT-S". The authors group has proposed a special kind of transmission with a dual-ball configuration for transmit drive powers to wheel shaft and steering shaft of an active-caster mechanism (ACROBAT). In the transmission design, two balls...
Citations
... Based on the same principle as that of the omni wheel, some omnidirectional wheel mechanisms have been developed, such as the Swedish wheel that has outer rollers arranged obliquely (Erland, 1974), an active omni wheel whose main body and outer rollers are both actively driven by using a differential gear mechanism (Komori et al., 2016), and an omnidirectional wheel with dual rings that are combined as a sphere driven by helical gears (Fujimoto et al., 2018). Another example that uses principles different from these mechanisms have also been developed: an omnidirectional vehicle in which the relative positions of the three wheels are variable (Terakawa et al., 2018), an omnidirectional vehicle that has caster type wheels with an offset between the steering axis and the ground contact point (Campion et al., 1996), and other various types of omnidirectional vehicles (Pin and Killough, 1994;West and Asada, 1995;Wada and Mori, 1997;Isoda et al., 1999;Yamashita et al., 2003;El-Shenawy et al., 2006;Mourioux et al., 2006;Tadakuma et al., 2008;Kumagai and Ochiai, 2008;Ren and Ma, 2015;Maeda and Ando, 2015;Masuda et al., 2017;Kato and Wada, 2018). ...
Human-powered vehicles, especially conventional wheelchairs, are essential tools for people with lower body disability. But their movement in a lateral direction is limited or impossible, which burdens users who want to change directions, especially in a narrow space. Thus, a human-powered vehicle that can move in a lateral direction is required. To move in any direction, many motor-driven omnidirectional vehicles have been proposed, but humans cannot manually power their mechanisms. To solve this problem, we are developing a human-powered vehicle, that is, driven by hands of the rider, that can move in both the longitudinal and lateral directions. This paper proposes such a vehicle, which has a mechanism to move in the lateral direction like people can do while walking. We designed it so that riders can operate its mechanism by analyzing the space reachable by the rider’s palms where they can effectively exert power. We constructed a prototype and conducted experiments to confirm that the vehicle moves as expected with relatively low effort. In the experiments, we confirmed the validity of vehicle operation by comparing the moving time of the vehicle with and without the lateral translation function for different travel distances and passage widths. Our results showed that the proposed vehicle moves more quickly or requires shorter moving distance in comparison with a conventional wheelchair because of the lateral movement function. In addition, we found that the threshold for utility of the function is whether the passage width is larger than the vehicle diagonal length.
