Disney has an big interest in animatronics – just try visiting one of their parks and avoiding it.
These are mainly kept at a very safe distance because either the visitor or the animatronic ‘robot’ are fragile compared to one another. Disney is all about interaction and asked the question – how can the animatronics and the visitors be safe around eachother? Disney Research Pittsburgh approached an old solution in a novel way – by removing some of the most problematic areas of working-fluid actuators in order to make a ‘softer’, friendlier animatronic.
The solution looks at first glance to be hydraulic – pressure lines connect pistons, allowing the actuator drive and the actuation posit to be separated. The system can work with an incompressible or compressible fluid.
The key difference over hydraulics is actually the lower performance – the lower working fluid pressure (100psi) and a unique ‘rolling gasket’ type seal in the pistons. This gasket reduces the problem of ‘sticktion’ (initial extra friction at the start of an actuation movement) to almost nothing, and reduces friction during travel as well. This requires less overall pressurization in the system to achieve smooth motion, and by moving the actuator motors off the robot itself, total mass is reduced, creating a positive feedback where less mass requires less actuation power. There are some design challenges that seem open, though: Continue reading