US Patent 7454909 Impedance shaping element for a control system

An impedance shaping element (or more simply, an impedance shaper) physically alters or shapes the mechanical impedance of a drive system as it appears from an interface and facilitates use of feedback control to improve performance by altering or shaping a dynamic coupling between an interface and a control system. For example, the impedance shaper can be used to adjust a coupling value from a first value to a second different value. In one embodiment, an impedance shaper controls the compliance, damping and inertia characteristics of fluid within a fluid path.