Haptic Hydrostatic Transmission
Our goal was to create a transmission and actuator system which would have applications in haptics and human-robot interaction.
When designing a robot to interact with humans it is advantageous to keep the mass of the arms as low as possible, to this end we designed a low friction, light weight fluid transmission system which has better torque density than an electric motor but suffers from less friction, and leaking, then traditional hydraulic or pneumatic systems.
The transmission system is based on rolling diaphragm actuators. The seal, or diaphragm, in these actuators inverts on itself and rolls up the piston shaft as the actuator moves. This has almost no friction, especially when compared to seals in traditional pistons which must slide along a moving surface. In addition, the rolling diaphragm seal is much less susceptible to leaks.