A fluid pressure actuator is provided with an actuator main portion whose shape is changed by the expansion or contraction of a cylindrical tube expanded and contracted by the pressure of fluid, and a detection unit for detecting the length L of the actuator main portion along the longitudinal direction of the tube.

An accumulator includes a housing, a flexible bladder and a support. The housing includes a chamber having a defined volume and a passage extending through the housing. The flexible bladder is positioned within the chamber and contains a compressible gas. The bladder being operable in an expanded condition and a partially collapsed condition. The support is positioned in the chamber and engages the flexible bladder when the flexible bladder is in the expanded condition. Liquid is positioned in the chamber and in contact with the flexible bladder. A volume of the liquid within the chamber is at a minimum when the flexible bladder is in the expanded condition. The volume of liquid within the chamber increases as a pressure of the liquid increases to compress the gas and operate the flexible bladder in the partially collapsed condition.

Artificial muscles are provided including 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 stiffening member positioned between the housing and at least one of the first electrode and the second electrode. The stiffening member increases a stiffness of the housing in a direction toward the expandable fluid region from an opposite edge of the electrode region. 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 directs the dielectric fluid into the expandable fluid region.

An artificial muscle stack that includes a plurality of artificial muscle layers. Each artificial muscle layer includes one or more artificial muscles having a housing with an electrode region and an expandable fluid region, a dielectric fluid housed within the housing, and an electrode pair having a first and second electrode positioned in the electrode region. The first and second electrodes each include two or more tab portions and two or more bridge portions. The two or more bridge portions interconnects adjacent tab portions. At least one of the first and second electrode includes a central opening positioned between the tab portions and encircling the expandable fluid region. The plurality of artificial muscle layers are arranged such that the expandable fluid region of the artificial muscles of each artificial muscle layer overlaps at least one tab portion of one or more artificial muscles of an adjacent artificial muscle layer.

An artificial muscle device includes a plurality of intermuscular boards and a plurality of artificial muscles disposed between the intermuscular boards in an alternating pattern and communicatively coupled to a controller. Each of the one or more artificial muscles includes a housing comprising an electrode region and an expandable fluid region, a dielectric fluid housed within the housing, and an electrode pair positioned in the electrode region of the housing, the electrode pair including a first electrode and a second electrode. 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 directs the dielectric fluid into the expandable fluid region, expanding the expandable fluid region, thereby applying pressure to the intermuscular boards.

An artificial muscle that includes a housing having an electrode region and an expandable fluid region and an electrode pair positioned in the electrode region, the electrode pair having a first electrode fixed to a first surface of the housing and a second electrode fixed to a second surface of the housing. The first and second electrodes each have two or more tab portions and two or more bridge portions. Each of the two or more bridge portions interconnects adjacent tab portions and at least one of the first and second electrodes includes a central opening positioned between the two or more tab portions and encircling the expandable fluid region. A dielectric fluid is housed within the housing and the electrode pair is actuatable between a non-actuated and an actuated state such that actuation from the non-actuated to actuated state directs the dielectric fluid into the expandable fluid region.

High strain hydraulically amplified self-healing electrostatic transducers having increased maximum theoretical and practical strains are disclosed. In particular, the actuators include electrode configurations having a zipping front created by the attraction of the electrodes that is configured orthogonally to a strain axis along which the actuators. This configuration produces increased strains. In turn, various form factors for the actuator configuration are presented including an artificial circular muscle and a strain amplifying pulley system. Other actuator configurations are contemplated that include independent and opposed electrode pairs to create cyclic activation, hybrid electrode configurations, and use of strain limiting layers for controlled deflection of the actuator.

A variable impedance actuator is provided with a bladder-style actuator having a first end and a second end, and a jamming brake located inside the bladder-style actuator and connected to the first end and the second end of the bladder-style actuator. The bladder-style actuator and the jamming brake are independently controlled.

An artificial muscle stack that includes a plurality of artificial muscle layers. Each artificial muscle layer includes one or more artificial muscles having a housing with an electrode region and an expandable fluid region, a dielectric fluid housed within the housing, and an electrode pair having a first and second electrode positioned in the electrode region. The first and second electrodes each include two or more tab portions and two or more bridge portions. The two or more bridge portions interconnects adjacent tab portions. At least one of the first and second electrode includes a central opening positioned between the tab portions and encircling the expandable fluid region. The plurality of artificial muscle layers are arranged such that the expandable fluid region of the artificial muscles of each artificial muscle layer overlaps at least one tab portion of one or more artificial muscles of an adjacent artificial muscle layer.

An artificial muscle including a housing having an electrode region and an expandable fluid region, the housing defining an upper housing portion and a lower housing portion, a strain sensor integrated into at least one of the upper housing portion and the lower housing portion of the housing, a dielectric fluid housed within the housing, and an electrode pair positioned in the electrode region of the housing. The electrode pair includes a first electrode and a second electrode, wherein the electrode pair is configured to actuate between a non-actuated state and an actuated state such that actuation from the non-actuated state to the actuated state directs the dielectric fluid into the expandable fluid region, expanding the expandable fluid region to deform the strain sensor.