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.

An unmanned aircraft includes a circuit board with an inertia sensor, a vibration damper configured to attenuate vibration of the inertia sensor, a weight block configured to provide support for positioning the circuit board, and a housing assembly configured to form an inner chamber to accommodate the circuit board and the weight block. The vibration damper includes a first vibration-attenuation cushion and a second vibration-attenuation cushion bonded respectively to a first side and a second side of the circuit board. The weight block is disposed between the first vibration-attenuation cushion and the circuit board.

An unmanned aircraft includes a circuit board with an inertia sensor, a vibration damper configured to attenuate vibration of the inertia sensor, a weight block configured to provide support for positioning the circuit board, and a housing assembly configured to form an inner chamber to accommodate the circuit board and the weight block. The vibration damper includes a first vibration-attenuation cushion and a second vibration-attenuation cushion bonded respectively to a first side and a second side of the circuit board. The weight block is disposed between the first vibration-attenuation cushion and the circuit board.

An active suspension system for a sprung mass that is supported and movable relative to an unsprung mass. The active suspension system has a suspension that comprises an electromagnetic actuator that is adapted to produce an arbitrary force on the sprung mass that is independent of the position, velocity and acceleration of the sprung mass, a control system that provides control signals that cause the suspension to exert force on the sprung mass, to control the position of the sprung mass relative to the unsprung mass, wherein the control system implements a control algorithm with one or more constants, and a user interface that is operable to cause a change of one or more of the control algorithm constants so as to vary how closely motion of the sprung mass follows motion of the unsprung mass.

An active suspension system for a sprung mass that is supported and movable relative to an unsprung mass. The active suspension system has a suspension that comprises an electromagnetic actuator that is adapted to produce an arbitrary force on the sprung mass that is independent of the position, velocity and acceleration of the sprung mass, a control system that provides control signals that cause the suspension to exert force on the sprung mass, to control the position of the sprung mass relative to the unsprung mass, wherein the control system implements a control algorithm with one or more constants, and a user interface that is operable to cause a change of one or more of the control algorithm constants so as to vary how closely motion of the sprung mass follows motion of the unsprung mass.

In a spring balancer apparatus, a flange includes a through-hole and a first and second flange member, the first flange member positioned radially inside a compression spring and removably held on another end of the shaft by a first nut member fastened to a first external thread on the shaft, the second flange member including a central hole and removably fixed to an outer periphery of the first flange member from a rear end plate side. The rear end plate of a casing includes an abutting part on which an outer periphery of the second flange member abuts, and an opening through which a surface of the second flange member is externally exposed at a position radially inside the abutting part and radially outside the central hole. At least one of a front end plate and the rear end plate is removably fixed to a cylindrical body of the casing.

In a spring balancer apparatus, a flange includes a through-hole and a first and second flange member, the first flange member positioned radially inside a compression spring and removably held on another end of the shaft by a first nut member fastened to a first external thread on the shaft, the second flange member including a central hole and removably fixed to an outer periphery of the first flange member from a rear end plate side. The rear end plate of a casing includes an abutting part on which an outer periphery of the second flange member abuts, and an opening through which a surface of the second flange member is externally exposed at a position radially inside the abutting part and radially outside the central hole. At least one of a front end plate and the rear end plate is removably fixed to a cylindrical body of the casing.

Methods and apparatus for reducing vibration for an acoustic array. In an embodiment, an acoustic array includes a base structure having apertures and sensors supported by the base structure for providing an acoustic array. Vibration damping material is located in the apertures of the base structure and attachment mechanisms for secure the portions of vibration damping material to a vehicle. A mold material encapsulates the base structure, the sensors and the portions of vibration damping material. The structure and materials are selected to dampen vibration for certain frequencies.