New Hybrid System Gives Robot Arms

Disney Research has developed a telepresence robot capable of playing the glockenspiel and even tossing balloons when not engaged in tasks like safely picking up fresh eggs. This robot features a novel hydrostatic transmission that combines hydraulic and pneumatic (air) lines, delivering enhanced degrees of freedom, precision, and delicate touch in a lighter and simpler design.

Traditionally, telepresence systems have relied on mechanical designs (gears, cables, linkages), hydraulics, or pneumatics, each with pros and cons:

Mechanical (cables, pulleys): Simple, sometimes requiring no external power, but limited in design flexibility and provide poor feedback/control.

Hydraulics: Powerful with good feedback, but bulky, inflexible lines and risk freezing if power cuts off.

Pneumatics: Lightweight and simple but poor load handling and imprecise.

The Disney team, led by John P. Whitney from Northeastern University, created a hybrid hydraulic/pneumatic system that uses a hydraulic line to actuate a joint in its primary direction and a pneumatic air line to return it. This setup acts like an air spring, moderating movement during reset.

Key benefits of this design:

Requires only a single motor, which can be placed flexibly.

Reduces bulky hydraulic lines by pairing them with more flexible air hoses.

Results in a system that is light, fast, dexterous, and low friction.

Faithfully transmits contact forces to the operator, delivering high-fidelity haptic feedback for a realistic remote sense of touch.

This innovation combines the power and control of hydraulics with the flexibility and lightness of pneumatics, overcoming limitations of earlier telepresence systems.