Various implementations include a device for controlling vibration with piecewise-linear nonlinearity. The device includes a stiffness element, a mass, a stopper, and an actuator. The stiffness element is expandable and compressible along an axis. The mass is coupled to the stiffness element. The mass has a resting mass position along the axis. The actuator is coupled to the stopper. The actuator is configured to move the stopper along the axis to vary a gap size. The gap size is measured as a distance between the resting mass position and a resting stopper position.

An electrically driven actuator includes a vibration damping device; and an electrically driven unit operated by using electricity. The vibration damping device includes a vibration absorbing unit provided between a first support and a second support provided to face the first support, and expanding and contracting by using electricity, a measurement unit that measures vibrations of the second support, and a control unit that electrically controls the vibration absorbing unit to cancel the vibrations of the second support which are measured by the measurement unit. The electrically driven unit includes a housing provided on a fixed side, a shaft movable in an axial direction which is a direction toward a movable side opposite to the fixed side with respect to the housing, and a drive unit provided between the housing and the shaft, and driving the shaft with respect to the housing.

The present disclosure discloses a Stewart vibration isolation platform with Macro Fiber Composite (MFC) plates. The vibration isolation platform includes: an upper load platform, a lower foundation platform, a controller, and a plurality of single-leg vibration isolation unit groups arranged between the upper load platform and the lower foundation platform. Each of the single-leg vibration isolation unit groups includes two single-leg vibration isolation units. The single-leg vibration isolation unit includes a first diaphragm spring and a second diaphragm spring. An MFC actuator and an MFC sensor are respectively arranged on two sides of the first diaphragm spring and the second diaphragm spring. The MFC actuators and the MFC sensors are all connected to the controller.

Described and shown are passive variable stiffness devices, which are of compact design and configured to produce a restoring force that varies optimally with the isolator displacement when subjected to vibration-inducing loading.

A vehicle damper assembly is disclosed. The damper includes a cylinder having an inner diameter (ID). A rod and a piston, the piston coupled to the rod and configured to divide the cylinder into a compression side and a rebound side. An electronic valve assembly including an electronic valve body coupled with the rod on the compression side of the piston. The electronic valve body having an electronic valve body outer diameter (OD). A boost valve having a boost valve body, a boost valve area located between the electronic valve body and the boost valve body, the boost valve having a boost valve OD. The boost valve OD is larger than the electronic valve body OD, such that the boost valve is configured to allow the electronic valve assembly to operate within said cylinder ID that is too large for the electronic valve body OD.

A damper assembly includes an outer tube and an inner tube disposed in the outer tube defining a reserve chamber. The inner tube defines an inner volume. A piston is slidably disposed in the inner tube and divides the inner volume into a rebound working chamber and a compression working chamber. A rebound valve is fluidly connected to the rebound working chamber and the reserve chamber, and a compression valve is fluidly connected to the reserve chamber and the compression working chamber. A rebound valve connector fluidly connects the rebound valve and the rebound working chamber and a compression valve connector fluidly connects the compression valve and the compression working chamber. The rebound valve connector includes a one-way valve from the reserve chamber to the rebound working chamber and the compression valve connector includes a one-way valve from the reserve chamber to the compression working chamber.

A wind power generation apparatus, a tower and a method for suppressing a tower shadow effect of the tower. The tower is provided with suction through holes extending through a circumferential wall thereof, and the suction through holes are distributed in a circumferential direction of the tower; the tower is further provided with a suction apparatus, and the suction apparatus can perform suction to the suction through holes from outside to inside. With the tower and the method, when the suction through holes at a windward side are suctioned, the adverse influence of the tower shadow effect can be weakened or eliminated, a service life of a pitch varying bearing can be prolonged, a noise can be reduced and a wind energy utilization coefficient can be improved. When the suction through holes at a position of a bypassing flow detachment are suctioned, vortex-induced vibrations can also be suppressed.

A system may detect a vibration being applied to a tuned vibration absorber. The tuned vibration absorber may include a beam, a mass, springs, a sensor, and an actuator. The mass may be disposed on the beam at a current position. The actuator may be configured to adjust a position of the mass on the beam. The system may identify a target position of the mass on the beam based on the detected vibration. The system may generate a drive signal, based on the target position, to control the actuator to adjust the position of the mass on the beam. The system may control the actuator to adjust the position of the mass from the current position on the beam to the target position on the beam to attenuate the vibration.

A solar tracker system includes a torque tube, a solar panel assembly attached to the torque tube, a housing defining a chamber and a fluid passageway extending from the chamber, and an active lock connected to a seal configured to prevent a flow path of fluid while in a sealed state and allow the flow path of fluid in an unsealed state. The system further includes a controller in communication with the torque tube and the active lock. The controller is programmed to receive a command to place the solar panel assembly in a stowed position, instruct the torque tube to rotate the panel assembly to a stowed angle corresponding to the stowed position, monitor a current angle of the panel assembly, compare the current angle to the stowed angle, and instruct the seal to transition to the sealed state when the current angle is equal to the stowed angle.

Solar tracker systems include a torque tube, a column supporting the torque tube, a solar panel attached to the torque tube, and a damper assembly. The damper assembly includes an outer shell surrounding an inner shell. A piston is at least partially positioned within the inner shell and moveable relative thereto. An active lock of the damper assembly includes a housing positioned within the outer shell. The housing defines a cavity and a housing channel extending from the cavity to an outer fluid channel. A shaft extends into the cavity and a valve assembly is attached to the shaft. The shaft is rotatable within the cavity between an unsealed position in which the housing channel is in fluid communication with the cavity, and a sealed position in which the valve assembly is rotationally aligned with the housing channel and obstructs fluid communication between the cavity and the housing channel.