A Novel Omnidirectional Mobile Robot With Wheels Connected by Passive Sliding Joints

Abstract

Mobile robots for automatically transporting products in factories and warehouses contribute to an increase in efficiency. Omnidirectional mobile robots can move immediately in an arbitrary direction and overcome the disadvantages of lack of mobility in conventional mobile robots. However, the omnidirectional mobile robots proposed in the past have not been as reliable as the conventional mobile robots such as AGVs due to their complicated wheel mechanisms. This research proposes a novel omnidirectional mobile robot named SWOM (slidable-wheeled omnidirectional mobile robot), which has three wheels that connect to the robot body by three passive sliding joints. The relative movements of the sliding joints allow SWOM to use conventional wheels. Thus, SWOM realizes both omnidirectional mobility and structural reliability. In this paper, we discuss the kinematic conditions for omnidirectional mobile robots and prove theoretically that SWOM can achieve omnidirectional movement. We present a kinematic analysis, a reachable region evaluation considering the limited movable range of the sliding joints, and trajectory generation that enables SWOM to move unlimitedly. We develop a prototype of SWOM and conduct experiments that show SWOM actually moves according to the theory. From the above, we verify the effectiveness of SWOM as an omnidirectional mobile robot.

Human-powered vehicle capable of movement in the longitudinal and lateral directions

“…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).…”

Network-Oriented Real-Time Embedded System Considering Synchronous Joint Space Motion for an Omnidirectional Mobile Robot

“…Comparatively, omnidirectional mobile robots are capable of arbitrary motion in any direction without reconfiguration of the wheels at any point in time. Motion in arbitrary directions is possible by employing specially designed wheels including sliding rollers [5], active casters [6], and Mecanum wheels [7,8]. To this end, we aim to develop a motion control system for a Mecanum-wheeled omnidirectional mobile robot.…”

Adaptive Sliding Mode Trajectory Tracking Control for WMR Considering Skidding and Slipping via Extended State Observer

“…With the increasingly widespread application of robotics, wheeled mobile robot (WMR) is required to perform many tasks, i.e., rescue operation [1], transportation products [2], social interaction [3], planetary exploration [4] and so on. High-performance control strategy is the prerequisites to implement the different practical tasks efficiently.…”