An actuator (1) is described having a first part (4), a second part (2), and a body portion (3) between the first and second parts, wherein the body portion includes at least one chamber (14) configured to be pressurised and the body portion has a longitudinal axis; and a plurality of cables (6,7,8,9), wherein each of the plurality of cables is arranged in a respective at least partial spiral with respect to the longitudinal axis of the body portion (3); and wherein the plurality of cables are arranged such that the application of a selected force to at least one of the cables causes a desired movement of the first part relative to the second part.

A dielectric elastomer system (DES) variable stiffness actuator (VSA) is provided. In an embodiment, the DES VSA includes a variable stiffness module (VSM). The VSM includes a DES that softens when energized and stiffens when unpowered, an outer frame, and an inner frame member. The stiffness of the DES is variable. The outer frame supports the DES and the inner frame member, which is disposed within the DES. The inner frame member is configured to be displaceable with respect to the outer frame. The DES VSA also includes an actuation motor mechanically coupled to the inner frame member that is configured to cause a force to be applied to the inner frame member and the actuation motor is configured to control an equilibrium position of the DES VSA.

Various embodiments provide a variable stiffness soft actuator inspired by an ossicle structure of echinoderm and a robot apparatus including the same. According to various embodiments, the soft actuate includes a plurality of ossicle elements arranged in a specific structure, wherein an interval between the plurality of ossicle elements is maintained or reduced depending on vacuum generation to change the stiffness of the soft actuator.

A magnetic-induced stiffness changed soft robot drive module includes magnetic-induced stiffness changed layer, two-degree-of-freedom pneumatic driver, magnetic core and sealing fixing device. The magnetic-induced stiffness changed layer and two-degree-of-freedom pneumatic driver are printed and formed. The magnetic core can be deformed together with the driver, and a magnetic field can be generated when it is energized. After the magnetic core is installed into the two-degree-of-freedom pneumatic driver, then assembled with the sealing fixing device, a soft robot drive module with one end fixed is finished. The magnetic-induced stiffness changed layer has the fast, reversible and controllable stiffness adjustment ability under the action of electromagnetic field. As its hardness is greater than that of the two-degree-of-freedom pneumatic driver and its position is outside the air cavity, the two-degree-of-freedom pneumatic driver can be restricted from over-expansion and over-extension in the axial direction, making its pneumatic bending deformation controllable.

A variable-stiffness actuator is to be installed into a flexible member and provide different degrees of stiffness to the flexible member. The actuator includes two hard members located apart from each other, and a shape-memory member connecting the hard members. The shape-memory member has a property of transitioning in phase between a first phase and a second phase. The shape-memory member is in a low stiffness state when in the first phase, and is in a high stiffness state when in the second phase. The actuator also includes a inducing member configured to cause a portion of the shape-memory member between the hard members to transition in phase between the first and second phases, and a urging member configured to urge the hard members in directions away from each other.

An actuator includes first and second ends defining an axis there between, and at least four inflatable chambers. Each inflatable chamber is resiliently deformable, elongate, and extends axially between the first and second ends and circumferentially about a central core defined between the ends and by the inflatable chambers. A first pair of the four inflatable chambers is contra rotatory about the core to a second pair of the four inflatable chambers. A pressure change in one or more of the inflatable chambers causes motion of the first end relative to the second end. The actuators can be employed in robots or robotic arms.

A series elastic actuator includes a gear configured to rotate, an output body configured to rotate by the gear, and an elastic body connecting the gear and the output body. The elastic body may include an outer ring fastened to the gear, an inner ring positioned inside the outer ring and fastened to the output body, and a deformation portion connecting the outer ring and the inner ring and deforming elastically. The elastic body may include a plurality of elastic bodies connected in parallel or in series.

A dielectric elastomer system (DES) variable stiffness actuator (VSA) is provided. In an embodiment, the DES VSA includes a variable stiffness module (VSM). The VSM includes a DES that softens when energized and stiffens when unpowered, an outer frame, and an inner frame member. The stiffness of the DES is variable. The outer frame supports the DES and the inner frame member, which is disposed within the DES. The inner frame member is configured to be displaceable with respect to the outer frame. The DES VSA also includes an actuation motor mechanically coupled to the inner frame member that is configured to cause a force to be applied to the inner frame member and the actuation motor is configured to control an equilibrium position of the DES VSA.

Variable stiffness devices and methods of their use are provided. In some embodiments, a variable stiffness device comprises an inner member defining a compartment for receiving an actuating fluid; an outer member disposed around the inner member; and a granular medium disposed between the inner member and the outer member; wherein the inner member is being moveable in a radial direction from a relaxed state to an expanded state by introducing the actuating fluid into the compartment of the inner member to compress the granular medium against the outer member to increase the stiffness of the device.

The present invention relates to an actuator module with a flexible unit, and more particularly, to an actuator module mounted on an articulated robot and having a flexible unit capable of detecting an abnormal load through sensor-based accurate load measurement to improve essential stability of the actuator module. The actuator module includes a drive unit for generating a rotational force, a deceleration unit connected to the drive unit to receive the rotational force therefrom for reducing a rotational speed transmitted thereto to increase the rotational force, a flexible unit connected to the deceleration unit to receive the rotational force therefrom and having a plurality of elastic members in a stacked form, the elastic members being variable by an external force, and an output unit connected to the flexible unit to receive the rotational force therefrom for outputting the transmitted rotational force to the outside, wherein the elastic members have the same elastic force or different elastic forces, and are selectively varied depending on the magnitude of the external force applied to the output unit.