Artificial muscles comprising a gradient stiffened electrode pair and artificial muscle assemblies including same

An artificial muscle comprising:

• a housing having an electrode region and an expandable fluid region;
• an electrode pair including a first electrode and a second electrode positioned in the electrode region of the housing;
• a dielectric fluid housed within the housing;
• and
• a pair of stiffening members positioned between the housing and each of the first electrode and the second electrode, the pair of stiffening members increasing a stiffness of the housing in a direction toward the expandable fluid region from an opposite edge of the electrode region,
• wherein the electrode pair is actuatable between a non-actuated state and an actuated state such that actuation from the non-actuated state to the actuated state causes a distance between the electrode pair proximate the opposite edge of the electrode region to be decreased prior to a distance between the electrode pair proximate the expandable fluid region being decreased.

A method for actuating an artificial muscle, the method comprising:

• providing a voltage using a power supply electrically coupled to an electrode pair of an artificial muscle, the artificial muscle comprising:
• a housing having an electrode region and an expandable fluid region;
• the electrode pair including a first electrode and a second electrode positioned in the electrode region of the housing;
• a dielectric fluid housed within the housing;
• and
• a stiffening member positioned between the housing and at least one of the first electrode and the second electrode, the stiffening member increasing a stiffness of the housing in a direction toward the expandable fluid region from an opposite edge of the electrode region, and
• applying the voltage to the electrode pair of the artificial muscle, thereby actuating the electrode pair from a non-actuated state to an actuated state such that the dielectric fluid is directed into the expandable fluid region of the housing and expands the expandable fluid region.