Parallel elastic mechanism for robot-environment force interaction

An actuator mechanism, comprising:

• a voice coil comprising a coil and a body with an iron core and a space about the iron core for receiving the coil;
• a body support supporting the body of the voice coil;
• a coil support supporting the coil of the voice coil;
• a shaft extending between the coil support and body support;
• a translational bearing in the body support for slidingly engaging an end of the shaft;
• and
• an elastic element coupled to the body and coil supports.

An apparatus for imparting a hopping motion to a supported load, comprising:

• a voice coil operable to provide translational motion;
• an elastic element;
• a prismatic guide assembly first supporting the voice coil to constrain the translational motion to be along a drive axis and second supporting the elastic element to constrain compression and expansion of the spring element along a longitudinal axis that is parallel to the drive axis of the voice coil;
• and
• a controller first controlling the voice coil to compress the elastic element during a first time period beginning when the apparatus is sensed to initially contact a surface and second controlling the voice coil to expand the elastic element during a second time period beginning when the apparatus is sensed to have zero velocity while contacting the surface.