A rotary engine that generates electricity using differences in relative humidity. A water-responsive material expands and contracts as water evaporates which drives the rotation of two wheels. The rotary motion drives an electrical generator which produces electricity. In another embodiment, the water-responsive material is used to actuate an artificial muscle of a robotic device.

A hybrid fiber with tunable stiffness includes a stiff fiber, a soft fiber connected in series to the stiff fiber, and a locking mechanism in contact with the soft fiber and configured to prevent the soft fiber from extending during a locked state, and to allow the soft fiber to extend during an unlocked state. The hybrid fiber has a substantially zero-bending resistance, irrespective of whether the soft fiber is in a locked or an unlocked state.

Disclosed is a method for fixing a soft actuator to a base, the soft actuator including a cylinder that includes a flange at an end in an axial direction, the cylinder being elastic in the axial direction and in a circumferential direction; and a coil that is wound around the cylinder in a spiral shape, suppresses a diameter expansion of the cylinder, and extends and contracts in the axial direction in accordance with an extension and contraction of the cylinder in the axial direction due to an increase and decrease in pressure within the cylinder, the base having a recess that has a groove, the method including engaging the flange and the groove with each other to fix the soft actuator to the base.

A method and system for providing an engine for producing mechanical energy through the absorption and evaporation of moisture uses a hygroscopic material in one or more configurations to do mechanical work. The hygroscopic material can include microbial spores, plant cells and cell materials, silk and hydrogel materials that absorb moisture and expand or swell when exposed to high relative humidity environments and shrink or return to nearly their original size or shape when exposed to low relative humidity environments wherein the moisture evaporates and is released. By exposing the hygroscopic material to a cycle of high relative humidity environments and low relative humidity environments, useful work can be done. One or more transmission elements can be used to couple the hygroscopic material to a generator that converts the mechanical energy to, for example, electrical energy. The hygroscopic material can be applied to flexible sheet materials that flex as the hygroscopic material absorbs or evaporates moisture. The hygroscopic material can also be applied to elastic conductive materials, such that the plates of a capacitor mechanically change the capacitance of the device.

A rotary engine that generates electricity using differences in relative humidity. A water-responsive material expands and contracts as water evaporates which drives the rotation of two wheels. The rotary motion drives an electrical generator which produces electricity. In another embodiment, the water-responsive material is used to actuate an artificial muscle of a robotic device.

Evaporation-driven engines are disclosed herein. An example engine can include a water source having a high humidity zone proximate the surface of the water source, a supporting structure, and a hygroscopic material disposed on the supporting structure and configured to generate mechanical force in response to a changing relative humidity. The hygroscopic material can be repeatedly exposed to the high humidity zone and removed from the high humidity zone thereby causing the hygroscopic material to generate mechanical force.

Provided are an actuation apparatus and an actuation method that belong to the field of actuation apparatus technology. The actuation apparatus includes a support seat, a swing arm, an braking arm, an elastic member, a first shape memory alloy line, and a second shape memory alloy line. The swing arm is mounted on the support seat and rotatable about a swing axis. The swing arm is provided with a first force-bearing portion, an execution portion, and an braking portion. The distance from the first force-bearing portion to the swing axis is shorter than the distance from the execution portion to the swing axis. The braking arm is movably mounted on the support seat. The elastic member is clamped between the support seat and the braking arm and configured to drive the braking arm to stop against the braking portion.

Apparatuses for utilizing transient pressures inherent in water mains to generate electrical power and methods of using the same. A solid-state energy harvester device comprises a cylindrical body configured to be installed inline with a fluid-carrying pipe system and defining a fluid path, a flexible sleeve disposed inside the cylindrical body and encompassing the fluid path, and a plurality of piezoelectric elements integrated into the flexible sleeve. The cylindrical body, flexible sleeve, and plurality of piezoelectric elements are configured such that transient pressures in the fluid flowing through the fluid path cause the flexible sleeve to flex and bend, exciting the plurality of piezoelectric elements to produce an electric current.

Disclosed is a method for fixing a soft actuator to a base, the soft actuator including a cylinder that includes a flange at an end in an axial direction, the cylinder being elastic in the axial direction and in a circumferential direction; and a coil that is wound around the cylinder in a spiral shape, suppresses a diameter expansion of the cylinder, and extends and contracts in the axial direction in accordance with an extension and contraction of the cylinder in the axial direction due to an increase and decrease in pressure within the cylinder, the base having a recess that has a groove, the method including engaging the flange and the groove with each other to fix the soft actuator to the base.

There is provided a fluid pressure actuator includes an elastic tube including a tube body and a reinforcement member and being radially expanded and axially contracted by a fluid pressure supplied to the tube body. The fluid pressure actuator includes a first holder mounted on a first end of the elastic tube, and a second holder mounted on a second end of the elastic tube. The fluid pressure actuator includes a plate member being provided between the first holder and the second holder, being arranged outside the elastic tube, and having a corrugated part. The fluid pressure actuator includes a coupling member holding the plate member and the elastic tube.