Slithertron
The snake robot was designed to be modular, with interchangeable segments. This allows robots of varying size and complexity to be constructed. Whilst most of the segments towards the center of the robot are the same size, segments get increasingly smaller towards the head and tail. This gives a more realistic profile. Importantly, although segments may vary in outer size, the parts used and the way a segment is constructed remains the same.
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The above set of images show the original prototype and give a clear indication on how segments are constructed and joined together. Notice the use of standard model making components. For example, the linkage mechanism can be purchased from Lynxmotion. Each segment contains two standard servo motors and the segments are joined together using a universal joint. Twin servos and a universal joint are required only if the robot is required to sidewind. Significant cost savings can be made if no sidewinding is required. That is, if you just want the snake just to slither, the advantages include:
- Only a single servo motor is required in each segment.
- A universal joint is not required - segments only need to move left and right.
- A reduction in power consumption and overall weight.
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The above images show the second prototype. It should be noted that brass inserts were used to allow countersunk hex screws to be used. This is not strictly needed and was for aesthetics only. Hopefully it can be seen in the first prototype images that only standard self tappers are needed, screwed directly into the plastruct to join everything together. This provides a very strong mechanical fixing. Each segment requires a small wheel, shown above. This is not used as part of the drive chain but allows the snake to move forward when undulating.
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The above images show the skinned version. Pretty much anything can be used to cover each segment. Thin aluminum sheets are used with the prototype but plastics of varying colours would be a very interesting alternative.
Electronics and Control
The biggest challenge is the wiring loom. Single servo controllers with multiple outputs would be unsuitable, as connecting all the of the servos to a single point would be unrealistic. The solution is to distribute the control. In this video:
there is a custom built servo controller every four segments. A single addressable line connects to the main controller board. This reduces the wiring demands considerably. This system works extremely well, but considerable improvements could be made. For example, a small and cheap single or dual servo controller could be mounted in each segment. This would allow each segment to be truly modular. People could buy additional segments to extend their robot, if required. The original snake "brain" was merely a microcontroller interface to an RC controller. Of course, this could be very easily made autonomous.
Miscellaneous
Profiles
