Design and Modeling of a New Drive System and Exaggerated Rectilinear-Gait for a Snake-Inspired Robot

2014 ◽  
Vol 6 (2) ◽  
Author(s):  
James K. Hopkins ◽  
Satyandra K. Gupta
Keyword(s):  
Comparative Study ◽  
Friction Force ◽  
High Speed ◽  
Drive System ◽  
Positive Trend ◽  
Rectilinear Motion ◽  
Linear Motion ◽  
Body Structure ◽  
Highly Effective ◽  
Variable Friction

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. Snake-inspired 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 multimaterial, variable friction force anchoring concept. A series of traction experiments are conducted to determine appropriate materials to be used in the friction anchor (FA) 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.

Analysis of a Low Effort Rectilinear Gait for a Snake-Inspired Robot

2013 ◽  
Author(s):  
James K. Hopkins ◽  
Satyandra K. Gupta
Keyword(s):  
High Speed ◽  
Linear Displacement ◽  
The Body ◽  
Positive Trend ◽  
Rectilinear Motion ◽  
Body Structure ◽  
Joint Effort ◽  
Cyclic Displacement ◽  
Robot Platform

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. Snake-inspired robots utilizing rectilinear motion, one of the primary gaits observed in natural snakes, have demonstrated favorable results on various terrains. However, previous variations of the rectilinear gait were inefficient in cyclic displacement. These gaits generated vertical waves traveling along the length of the robot. Generating these waves required significant joint energy for relatively small horizontal displacements. This paper presents analytical and experimental results for a rectilinear gait, which demonstrates significant linear displacement for relatively low joint effort. The low effort gait functions by propagating a wave through the length of the robot via expansions and contractions of the body segments, propelling the robot platform forward. The low effort rectilinear gait is demonstrated on a robot platform that incorporates high speed linear motion and variable traction through friction. We also report the results of a case study showcasing the practical benefits of the low effort gait.

High-Performance Motion Control With Slosh: A Constrained Sliding Mode Approach

2008 ◽  
Author(s):  
Hanz Richter ◽  
Kedar B. Karnik
Keyword(s):  
High Speed ◽  
High Performance ◽  
Design Methodology ◽  
Closed Loop ◽  
Sliding Mode ◽  
Initial Conditions ◽  
Rectilinear Motion ◽  
Industrial Setting ◽  
Open Container ◽  
Nominal Performance

The problem of controlling the rectilinear motion of an open container without exceeding a prescribed liquid level and other constraints is considered using a recently-developed constrained sliding mode control design methodology based on invariant cylinders. A conventional sliding mode regulator is designed first to address nominal performance in the sliding mode. Then an robustly-invariant cylinder is constructed and used to describe the set of safe initial conditions from which the closed-loop controller can be operated without constraint violation. Simulations of a typical transfer illustrate the usefulness of the method in an industrial setting. Experimental results corresponding to a high-speed transfer validate the theory.

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