Body undulation used by snakes and the physical architecture of a snake body may offer significant benefits over typical legged or wheeled locomotion designs in certain types of scenarios. A large number of research groups have developed snake-inspired robots to exploit these benefits. The purpose of this paper is to report different types of snake-inspired robot designs and categorize them based on their main characteristics. For each category, we discuss their relative advantages and disadvantages. This paper will assist in familiarizing a newcomer to the field with the existing designs and their distinguishing features. We hope that by studying existing robots, future designers will be able to create new designs by adopting features from successful robots. The paper also summarizes the design challenges associated with the further advancement of the field and deploying snake-inspired robots in practice.
In recent years, snake-inspired locomotion has garnered increasing interest in the bio-inspired robotics community. This positive trend is largely due to the unique and highly effective gaits utilized by snakes to traverse various terrains and obstacles. These gaits make use of a snake's hyper-redundant body structure to adapt to the terrain and maneuver through tight spaces. Snakeinspired robots utilizing rectilinear motion, one of the primary gaits observed in natural snakes, have demonstrated favorable results on various terrains. However, previous robot designs utilizing rectilinear gaits were slow in speed. This paper presents a design and an exaggerated rectilinear gait concept for a snake-inspired robot which overcomes this limitation. The robot concept incorporates high speed linear motion and a new multi-material, variable friction force anchoring concept. A series of traction experiments are conducted to determine appropriate materials to be used in the friction anchor design. The gait concept includes four unique gaits: a forward and a turning gait, which both emphasize speed for the robot; and a forward and turning gait which emphasize traction. We also report a comparative study of the performance of prototype robot designed using these concepts to other published snake-inspired robot designs.
Snake-inspired locomotion is much more maneuverable compared to conventional locomotion concepts and it enables a robot to navigate through rough terrain. A rectilinear gait is quite flexible and has the following benefits: functionality on a wide variety of terrains, enables a highly stable robot platform, and provides pure undulatory motion without passive wheels. However, historically speed has been a limitation for the locomotion type. In this paper, Fused Deposition Modeling (FDM) is utilized to reduced the weight and thereby increase the speed potential of a snakeinspired robot design based on a rectilinear gait. FDM also provides feasibility for development of complex and capable mechanism designs for executing rectilinear motion. The new design is analyzed, fabrication and evaluated based on various anchoring material velocity experiments.
Snake-inspired locomotion is much more maneuverable compared to conventional locomotion concepts and it enables a robot to navigate through rough terrain. A rectilinear gait is quite flexible and has the following benefits: functionality on a wide variety of terrains, enables a highly stable robot platform, and provides pure undulatory motion without passive wheels. These benefits make rectilinear gaits especially suitable for search and rescue applications. However, previous robot designs utilizing rectilinear gaits were slow in speed. This paper introduces a new class of rectilinear gaits to be utilized by a snake-inspired robot design which is capable of pure linear motion and variable traction. The general model for the gait class is based on serial robot dynamics using the Lagrangian formulation. The gait class includes four unique gaits: a forward and a turning gait, which both emphasize speed for the robot; and a forward and turning gait which emphasize traction. Also, we perform an analysis of the variable traction concept.
Physical parameters of the constituent modules and gait parameters affect the overall performance of snake-inspired robots. Hence, a system-level optimization model needs to concurrently optimize the module parameters and the gait. Incorporating a physics-based model of rectilinear gaits in the system-level optimization model is a computationally challenging problem. This paper presents a case study to illustrate how metamodels of the precomputed optimal rectilinear gaits can be utilized to reduce the complexity of the system-level optimization model. An example is presented to illustrate the importance of concurrently optimizing the module parameters and the gait to obtain the optimal performance for a given mission.
Physical parameters of modules and gait parameters affect the overall snake-inspired robot performance. Hence the system-level optimization model has to concurrently optimize the module parameters and the gait. The equations of motion associated with the rectilinear gait are quite complex due to the changing topology of the rectilinear gait. Embedding these equations in the system-level optimization model leads to a computationally challenging formulation. This paper presents a system-level optimization model that utilizes a hierarchical optimization approach and meta-models of the pre-computed optimal gaits to reduce the complexity of the optimization model. This approach enabled us to use an experimentally validated physics-based model of the rectilinear gait and yet at the same time enabled us to create a system-level optimization model with a manageable complexity. A detailed case study is presented to show the importance of concurrently optimizing the module parameters and the gait using our model to obtain the optimal performance for a given mission.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.