Sci-Art: Bio-Robotic Choreography Project

Website deposited by Barry Smith, University of Bristol, 2006 and implemented into AHDS content delivery system.

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Robot Design

Robotics has all sorts of implications and uses. The Evolutionary and Adaptive Systems group look at interfaces between biology and technology. In this sense, the Bio-Robotic Choreography project fits naturally within this ethos.

Your position in the ideological debate determines how you begin to build a robot: The traditional 'Artificial Intelligence' view is that the brain controls the legs in a 'top-down' model. The alternative view as will be employed in the design of this robot is that the dynamics of movement come not from the brain but from the natural physics in a 'bottom-up' model.

The 6-legged robot will use a pentagraph mechanism where the movement of the foot is mirrored by the joint at opposite end. The effect is that the robot is hanging from a virtual pendulum in the sky. This will help the robot to stay on it's feet. Stationary it will be nearly 5 metres across and measure 2 metres from knee to foot. The designers are hoping to limit the weight to less than 250 kgs.

The design is symmetrically hexagonal allowing the robot to walk in any direction triggered by a turntable. Walking movement comes from lifting tripods of legs. Stelarc's leg movements will be amplified to pick up tripods of legs. There will be upto 4 modes of action - squat/lift - walk away -swiveling - turn on the spot.

The body's movement is incorporated into the sway of the robot. As Stelarc shifts his weight so will the robot and vice versa - riding rather than controlling it. The robot can rise from floor level to two metres high.

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Winch and pneumatic system for legs

Note that the robot has a "HIGH" level, a "WALKING" level and a "LOW" level (belly to the floor). These levels are preset with the winch system. They cannot be altered during locomotion.

1. The winch cable is split into 2 - each cable then splitting into 3 more that go to 2 sets of legs.
2. Each set of 3 legs is thus paired to the feet of the operator.
3. By shifting his body weight from one foot to the other, each set of
4. 3 legs is activated.
5. "Pedals" on the turntable make this stepping possible.
6. The pneumatic cylinders "pushing-out" and "pulling-in" the levers injects energy into the system enabling locomotion to occur indefinately.
7. 6. Simultaneously, the body turning on the turntable changes the direction it is walking.

Leg shape and dimensions

1. The lower leg consists of an aluminium scaffolding pipe measuring 48x1750mm and a steel rod measuring 12x2000mm.
2. This connects to a knee-type joint that utilises roller bearings and a 15mm steel rod pin to provide manoeuvrability.
3. The upper leg consists of an aluminium rectangular box measuring 40x100x1350mm and an aluminium square box measuring 40x40x1350mm.
4. The final section of the leg is a 10x10x700mm steel plate that provides cable support to the upper body.

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