Force feedback devices using fluid braking

Abstract

A haptic feedback device including a fluid viscosity-controlled brake that outputs high forces to the device user at low cost while maintaining inherent safety. An interface device includes a manipulandum physically contacted by the user. A sensor senses a position of the manipulandum and outputs a sensor signal. The interface device also includes a brake including a field-controlled fluid having a viscosity that can be controlled by controlling an electric current in a coil, where a resistive force or drag on the manipulandum is controlled by controlling the fluid's viscosity. The fluid can be an electrorheological fluid controlled by an electric field or a magnetorheological fluid controlled by a magnetic field. In one preferred embodiment, the resistive force is controlled by adjusting a degree of contact of the brake with the manipulandum based on the fluid's viscosity.

1 . A haptic feedback interface device manipulated by a user and providing input signals to a host computer, the interface device comprising: 
 a manipulandum physically contacted by said user and moveable in at least one degree of freedom;    a sensor that senses a position of said manipulandum in said at least one degree of freedom and outputs a sensor signal, wherein a representation of said sensor signal is provided to said host computer; and    a brake including a fluid having a viscosity that can be varied by adjusting an electromagnetic field in said fluid, wherein said electromagnetic field is adjusted by modulating an electric current, wherein a resistive force on said manipulandum is controlled by adjusting said current and thereby adjusting said viscosity.