机器人技术作业sasidewiding snake

1、Sidewiding otionSA14009047 马英Background of SidewidingSidewinding is an efficient gait employed by some snakes when crossing relatively open terrain. It is most commonly exhibited by snakes on loose or slippery surfaces, such as sand and mud, that cannot provide the lateral resistance required for sl

2、ithering. For similar reasons, sidewinding is a favored gait for snake robots that eschew passive wheels (such as our Modsnakes). Avoiding such wheels increases the robustness of the system while reducing its size, but also increases the ratio of longitudinal to lateral friction, impeding slithering

3、 performance. Sidewinding does not rely on this friction ratio, and so retains its efficiency when applied to such systems.Sidewinding ModelThe basic principles of sidewinding have been understood in the biology community since the late 1920s, based on experimental observations by Mosauer. In the ro

4、botics community, Burdick, Radford, and Chirikjian added a rigorous mathematical foundation to the study of sidewinding, providing the standard sidewinding model shown below, along with a modal formulation for shapes that satisfy its constraintsExplanation of ModelIn this sidewinding model, the grou

5、nd contact segments are in static contact with the ground. At their leading edges, the snake is continually lowering itself to the ground, while simultaneously peeling itself up at the trailing edge. The raised portions of the snakes body are arch segments. As the snake sidewinds, the ground contact

6、 segments leave ground contact tracks against the terrain; each of these segments is one body-length long and the net direction of travel is given by the offset between these tracks.Virtual Tread Sidewinding Model The standard sidewinding model is comprehensive, but the complex three-dimensional mot

7、ion it describes requires many parameters. To simplify analysis of this gait, I developed the virtual tread model for sidewinding. In this model, the snakes backbone is considered as a helix wrapped around a virtual core, such as an elliptical cylinder:Sidewinding is like a “Rolling Spring” Revolvin

8、g the backbone curve around the core (in the manner of a tracked vehicles treads) propels the core laterally. It also induces changes in the backbone shape that are consistent with the full sidewinding model, with the rolling contact of the tread equivalent to the laying down and peeling motions in

9、the standard model. This tread model is related to Mosauers observations that sidewinding is like a “rolling spring,” but the tread model allows for non-circular core shapes and is thus a useful analytical tool as well as an intuitive analogy.Sidewinding is like a “Rolling Spring” The virtual tread

10、sidewinding model can be further reduced by projecting it along its axis. We have used this projection to analyze the stability of sidewinding snake robots moving along sloped surfaces,with good agreement between the predicted and measured maximum slopes on which the sidewinder could balance for different aspect ratios:Aspect ratio