Patent ID: 7118601

Claim:
In combination, a parallel linkage for connecting two link mounting portions spaced from each other, comprising: a fixed link having one end thereof fixed to one of the link mounting portions; a fixed-link joint for connecting another end of said fixed link to another of the link mounting portions such that an angle of said fixed link with respect to the another of the link mounting portions can be changed in any desired direction; a plurality of expansible links extending between the two link mounting portions in an expansible/contractible manner, wherein said plurality of expansible links are at least three expansible links; a plurality of expansible-link joints respectively connecting opposite ends of said plurality of expansible links to the link mounting portions such that respective angles of each expansible link with respect to the link mounting portions can be changed in any desired direction a drive source; actuators each for actuating a corresponding one of said at least three expansible links for expansion and contraction by a driving force supplied from said drive source, wherein said each actuator is an electric actuator configured to produce regenerative power when said corresponding expansible link is expanded and contracted by an external force; control means for controlling said driving force supplied to said each actuator from said drive source; and an accumulator for storing the regenerative power produced by each said electric actuator.