Conference Paper

Design and implementation of Omni-directional spherical modular snake robot (OSMOS)

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Abstract

Control, motion estimation, and planning of highly articulated snake robots have been challenging tasks for researchers. Even traversal on simple flat trajectory requires complex models of planar snake robot locomotion. This paper presents a novel design of an Omni-directional planar snake robot (OSMOS) consisting of mechanically and software linked spherical robot modules. This new design eliminates the problems of planar snake robots to handle versatile motions with complex gait analysis, by leveraging Omni-directional motion capabilities of spherical robots. This paper also presents the basic robot gaits which clearly demonstrate its design advantages such as fast turn speed and present simpler motion planning strategies. Experimental results that verify the effectiveness of this robot architecture and gaits that have been designed to traverse flat terrain are included.

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... In our previous work [20], we presented the design of omnidirectional snake robot (OSMOS) on the basis of above considerations. But the robot links connecting the adjacent modules were rigid and incapable of bending in the vertical plane. ...
... Though obstacle avoidance is a solution a wider obstacle needs to be overcome by climbing it. This intrigued us to introduce compliance in the links such that the robot can also now bend in the vertical direction using passive compliance of the links [20].Compliance with the link is incorporated by adding a pair of symmetric torsional springs in the links. The calculation of the spring constants are done mathematically by using a quasi-static analysis similar to the spring modelling calculations done in [21,22]. ...
... In our previous work [20] link assemblies were connected by passive rigid rods as shown in Fig.6. However, the the updated design focuses on introducing a compliant joint at the end of each passive rod near to the central spherical module as shown in Fig (7) such that the link can now bend about this the pivot point in the vertical plane. ...
Conference Paper
Full-text available
Control, motion estimation, and planning of highly articulated snake robots have been challenging tasks for researchers. Even traversal on simple flat trajectory requires complex models of planar snake robot locomotion. Apart from flat trajectories formulating gaits for the modular structure to overcome obstacles is mathematically complicated. This paper presents a novel design of an Omni-directional snake robot (OSMOS) consisting of mechanically and software linked spherical robot modules. This new design eliminates the problems of planar snake robots to handle versatile motions with complex gait analysis, by leveraging Omni-directional motion capabilities of spherical robots. The robot is also capable of climbing smooth obstacles by introducing compliant joints in the links interconnecting adjacent modules. This paper also presents the basic robot gaits which clearly demonstrate its design advantages such as fast turn speed and present simpler motion planning strategies. Experimental results that verify the effectiveness of this robot architecture and gaits that have been designed to traverse flat terrain are included. Also, the spring stiffness of the passive joints in the links is calculated and simulation results for obstacle climbing are included.
... In our previous work [20], we presented the design of omnidirectional snake robot (OSMOS) on the basis of above considerations. But the robot links connecting the adjacent modules were rigid and incapable of bending in the vertical plane. ...
... Though obstacle avoidance is a solution a wider obstacle needs to be overcome by climbing it. This intrigued us to introduce compliance in the links such that the robot can also now bend in the vertical direction using passive compliance of the links [20].Compliance with the link is incorporated by adding a pair of symmetric torsional springs in the links. The calculation of the spring constants are done mathematically by using a quasi-static analysis similar to the spring modelling calculations done in [21,22]. ...
... In our previous work [20] link assemblies were connected by passive rigid rods as shown in Fig.6. However, the the updated design focuses on introducing a compliant joint at the end of each passive rod near to the central spherical module as shown in Fig (7) such that the link can now bend about this the pivot point in the vertical plane. ...
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Control, state estimation and motion planning of highly articulated snake robots have been challenging tasks for researchers. As a result, formulating gaits for the modular structure, for motion on flat trajectories as well as overcoming obstacles is mathematically complicated. This paper presents a novel design of a Compliant Omni-directional snake robot (COSMOS) consisting of mechanically and software linked spherical robot modules. This design eliminates the problems of planar snake robots to handle versatile motions with complex gait analysis, by leveraging Omni-directional motion capabilities of spherical robots. The robot is also capable of climbing smooth obstacles by introducing compliant joints in the links interconnecting adjacent modules. This paper also presents the basic robot gaits and their motion analysis which clearly demonstrate the robot design advantages such as fast turn speed and simpler motion planning strategies. Experimental results that verify the effectiveness of this robot architecture and gaits that have been designed to traverse flat terrain are included. Also, the spring stiffness of the passive joints which provide the vertical compliance in the links joining the modules is calculated and simulation results for obstacle climbing are included.
... Fig. 1 shows different mobility modes considered in this research, and Fig. 2 provides a summary of the strengths and weakness of each mobility mode. Snake robots, due to their hyper redundancy and narrow cross-section of their body, are versatile and can navigate within limited space, rough terrains, move underwater [1], traverse through pipes, slopes, and uneven ground [2], [3], [4]. Snake robots can be deployed for various practical applications like locating hazardous chemical leaks, search and rescue operations [5], reconnaissance; they can function as self-propelled inspection devices [6], [7], [8]. ...
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The selection of mobility modes for robot navigation consists of various trade-offs. Snake robots are ideal for traversing through constrained environments such as pipes, cluttered and rough terrain, whereas bipedal robots are more suited for structured environments such as stairs. Finally, quadruped robots are more stable than bipeds and can carry larger payloads than snakes and bipeds but struggle to navigate soft soil, sand, ice, and constrained environments. A reconfigurable robot can achieve the best of all worlds. Unfortunately, state-of-the-art reconfigurable robots rely on the rearrangement of modules through complicated mechanisms to dissemble and assemble at different places, increasing the size, weight, and power (SWaP) requirements. We propose Reconfigurable Quadrupedal-Bipedal Snake Robots (ReQuBiS), which can transform between mobility modes without rearranging modules. Hence, requiring just a single modification mechanism. Furthermore, our design allows the robot to split into two agents to perform tasks in parallel for biped and snake mobility. Experimental results demonstrate these mobility capabilities in snake, quadruped, and biped modes and transitions between them.
... On a different direction, the propulsion of the OmniTread snake robots was achieved by tank treads on all four sides of every link, which can help the robot move in complex environments (Armada et al., 2005). More recently, the OSMOS snake utilizes spherical shaped modules to help realize gaits without changing the robot body shape and orientation (Singh et al., 2017). Meanwhile, a lot of researchers have made progress on the study of snake robot locomotion. ...
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... MorpHex, in Figure 4a [118], is a reconfigurable hybrid robot that can move either by rolling or as a hexapod. A reconfigurable snake/biped robot is shown in Figure 4b [119], while the robot in [120] combines omni-directional wheels and slithering. ...
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