15 results about "Induced oscillations" patented technology

The invention discloses a piezoelectric-triboelectric hybrid power generation device and method based on flow-induced shaking, the device comprises a flow-induced shaking module, the flow-induced shaking module comprises a base, a rotating rod capable of rotating along the base is arranged on the base, a cantilever beam is arranged on the rotating rod, the inner end of the cantilever beam is arranged on the rotating rod, and the outer end of the cantilever beam is arranged on the base. The cantilever beam is provided with a piezoelectric module, the piezoelectric module comprises a piezoelectric plate, and the piezoelectric plate is connected with a first collection circuit; a solid-liquid friction nanometer power generation module is arranged at the outer end of the cantilever beam, the solid-liquid friction nanometer power generation module comprises a container, friction liquid, a friction layer and an electrode are arranged in the container, and the electrode is connected with a second collection circuit.

The invention relates to the technical field of wind driven generators, and discloses a rigid inverted cone vortex-induced swing vibration type wind driven generator which comprises a shell, a wire, a permanent magnet, a spherical hinge, a base, a return mechanism and a lubricating mechanism. The wire is installed on the inner wall of the shell, the shell is fixedly connected with a ball seat of the spherical hinge, and the permanent magnet is fixedly connected with a ball head of the spherical hinge; the base is fixedly connected with a ball head of the spherical hinge, the return mechanism is arranged on the inner wall of the base, and the lubricating mechanism is arranged in the spherical hinge. An independent motor is not needed, the structure is more compact, any transmission mechanism is not needed, energy loss is reduced, the wind energy conversion rate is increased, and wind energy capture at any angle can be achieved.

A scanning probe microscope (10) is described, comprising a probe (1) with a cantilever (11) carrying a tip (12), the scanning probe microscope configured to generate a first actuating motion changing a distance of the tip (12) with respect to a sample surface, a detector (4) configured to detect a tip position and to output a tip position signal, a control circuit (5) configured to generate a first control signal using the tip position signal, the scanning probe microscope being configured to generate a second actuating motion adapting a distance between the probe (1) and the sample surface using the first control signal, wherein the control circuit (5) is configured to generate a second control signal, the scanning probe microscope being configured to generate, using the second control signal, a third actuating motion at least partially opposing detachment-induced oscillations of the cantilever (11) induced by detaching of the tip (12) from the sample surface while retracting the probe (1).

The application discloses an online differential model-based flight control and pilot operation monitoring system optimization method, and belongs to the field of airplane design and airplane system design. Firstly, the flight stages of an airplane in flight are divided according to the flight characteristics of the airplane. Then, initial control models of the flight stages are established by using the operation statistical data of different pilots of the airplane in the flight stages. Finally, the initial control models of the flight stages of the same pilot are updated in the flight process of the airplane, and are changed into the differential model of the pilot, and the differential model of each pilot is taken as a benchmark to solve the pilot abnormal operation monitoring and the pilot-induced oscillation problem. The application can update the differential model online, provide more accurate model input for airplane related systems, and improve the system operation precision and efficiency.

The invention relates to the technical field of vehicles, in particular to a method and device for rapidly checking noise problems caused by cavity flow-induced oscillation and a medium. The method comprises the steps of judging whether a current vehicle has problem noise; if the problem noise exists in the current vehicle, when the problem noise does not have the preset order characteristic and a preset relation exists between the problem noise and the vehicle speed or the wind speed of the current vehicle or the internal flow speed of a vehicle pipeline, the center frequency and the airflow speed of the problem noise are obtained; calculating the feature length of the vocal cavity according to the center frequency, calculating the opening size of the vocal cavity according to the center frequency and the airflow velocity, and determining the generation position of problem noise according to the feature length of the vocal cavity and the opening size of the vocal cavity. Therefore, the problems that in the prior art, when cavity flow-induced oscillation noise occurs in a vehicle, a large number of tests and multiple investigation are needed, time and labor are wasted, and efficiency is low are solved, and the experience feeling and comfort of a user are improved.

An electric motor controller is equipped to mitigate drive line induced vehicle vibration. The motor speed is measured at the output of the motor, separately from any measurement of drive shaft or wheel speed. At least bandpass filtering is applied to the measured motor speed, at a pass band based on the natural frequency of the drive shaft. The filtering detects drive line induced oscillations of the motor speed. A controller uses the detected drive line induced oscillations to generate an oscillation control output, subject to limiting. An oscillation mitigation torque signal corresponding to the control output is added to a torque command for desired motor speed, to adjust for the oscillations. The adjusted torque command is used to control the motor, with a significant reduction in the oscillation of the motor's speed.

The invention belongs to the field of power system stability analysis, and particularly relates to a low-voltage ride-through induced oscillation analysis method based on a phase plane method. In recent years, oscillation instability phenomena of multi-time crossing control participation and repeated fluctuation of voltage and active power output occur at home and abroad, and primary analysis finds that the oscillation instability phenomena correspond to switching oscillation participated in a low-crossing control link. In order to analyze boundary conditions of the low-pass induced oscillation, a simplified switching system established based on a current loop is converted into a general second-order switching system; calculating and discussing the allowable balance point position and property of the general second-order switching system; and according to the position and the property of the balance point, analyzing a low-pass induced oscillation mechanism of the second-order switching system under positive damping, and giving a general conclusion. According to the method, a detailed new solution thought is provided for the boundary conditions of low-voltage-ride-through induced oscillation caused by unreasonable balance points, and a theoretical reference is provided for dispatching and operation parameter giving of new energy wind power connected to a power grid through a converter.

The invention relates to a method (100) for determining a density measurement of a medium by means of a Coriolis mass flow measuring transducer (10) having two oscillators (12, 14) and a pair of measuring tubes (12a, 12b, 14a, 14b) arranged one above the other. The measuring tubes (12a, 12b, 14a, 14b) are fluid-parallel and are guided into a collector (18) at an inlet side and an outlet side. Mounting the measuring transducer in a pipe causes mechanical stresses which can influence the oscillators via the collector. The medium is conducted in the measuring tubes. The method (100) comprises the following steps: (110) inducing at least one oscillation mode of the first oscillator and at least one oscillation mode of the second oscillator; (120) determining the natural frequency of each induced oscillation mode; (130) determining a respective temporary density measurement from the respective natural frequency; (140) determining a deviation between the temporary density measurements; and (150) determining a corrected density measurement by means of a model which determines and corrects the influence of the mechanical stresses on the density measurement on the basis of the deviation determination.

A control method and apparatus for hydropower output regulation, an electronic device, and a storage medium. The method comprises: acquiring a hydropower output target value and an actual hydropower output value within a current time period (101); on the basis of the hydropower output target value and the actual hydropower output value within the current time period, determining, within the current time period, a first time range during which induced oscillation occurs (102); determining a target phase compensation value on the basis of the hydropower output target value and the actual hydropower output value within the first time range (103); and performing phase compensation on hydropower output regulation on the basis of the target phase compensation value (104). In this way, when induced oscillation occurs during hydropower output regulation, the effect of hydropower output regulation is improved by means of phase compensation, thereby ensuring the safety and stability of an electric power system.

This application relates to a metal material identification system, method, and medium based on dual-coil detection and dynamic frequency scanning, belonging to the field of inductive sensor technology. The metal material identification system includes: a dual-coil detection module, used to generate a sweep signal within a preset frequency range according to a coil control signal, to excite the eddy current effect of the target object, and to detect and amplify the corresponding induced oscillation signal; a digital output module, used to output the material identification result of the target object; and a control module, used to generate a coil control signal according to the sweep parameters, receive the induced oscillation signal, calculate the metal quality factor, and match and identify the material of the target object by combining a preset material standard parameter range. Through dual-coil mutual inductance verification and dynamic frequency scanning technology, the dependence on material is reduced, and high-precision identification of all-metal materials is achieved, meeting the application scenarios for mixed materials.

The invention discloses a vortex-induced oscillation suppression device and a ship berth system, and the device comprises a sheath which is used for sleeving a mooring cable; the multiple spiral strakes are arranged on the outer surface of the sheath and are sequentially arranged in the circumferential direction of the sheath; each spiral strake comprises a plurality of segmented structures, and the segmented structures are sequentially arranged at intervals in the axial direction of the sheath; the segmented structure comprises a rectangular structure part, the cross section of which is rectangular along the radial direction of the sheath; the back flow side of the rectangular structure part is attached to the sheath; the radial section of the triangular structure part along the sheath is triangular, and one side of the triangle is attached to the incident flow side of the rectangular structure part, so that for the overall structure of the spiral strake, the incident flow side is of a sharp edge structure, asymmetric disturbance is artificially introduced, periodic vortex formation is destroyed, the incident flow contact area is effectively reduced, fluid separation points are dispersed, and the flow separation effect is improved; the fluid resistance is reduced, and the overall turbulent flow is enhanced, so that the aim of improving the vortex-induced oscillation suppression effect is fulfilled.

This invention discloses a testing device and method for the influence of vortex-induced oscillations on suspended sections of submarine cables. The device includes: a submarine cable connection module, a vortex-induced oscillation motion generation module, and a force-displacement sensing module. The submarine cable connection module sets the bending angle and span of the suspended section of the submarine cable to a preset bending angle and a preset span, respectively. The vortex-induced oscillation motion generation module applies a preset external force to the suspended section of the submarine cable and controls the direction of motion and the corresponding motion time. The force-displacement sensing module acquires the stress and displacement of the suspended section of the submarine cable under the preset bending angle, preset span, preset external force, direction of motion, and motion time. By implementing this invention, the influence of vortex-induced oscillations on suspended sections of high-voltage submarine cables can be tested.

The present application relates to a kind of rigid plate behind square column vortex-induced oscillation suppression combination structure and its design method, combination structure includes square column and the rigid plate of being set to square column rear;Its design method includes: S1 single square column vortex-induced oscillation numerical simulation in flow around;S2 square column vortex-induced oscillation numerical simulation of rigid plate combination structure behind in flow around;S3 compare single square column and square column rigid plate combination structure vortex-induced oscillation kinematics and dynamics response;S4 obtain the model parameter of square column rigid plate combination structure with the best vibration reduction, drag reduction effect.The present application can effectively reduce lift coefficient oscillation amplitude and the mean of resistance coefficient, and then reduce structural oscillation, realize vortex-induced oscillation suppression, the numerical analysis method for the rigid plate parameter design and optimization of square column behind proposed in the present application can more economically, efficiently and accurately design structure shape, size, not limit rigid flat material parameter, size, specific placement position, and the complexity of flow field environment.

The present invention discloses an energy harvester based on vortex-induced oscillation. By providing a rotating base, a support column, an energy harvesting column, and a contact-separation friction generator, after water flows through the energy harvester, the energy harvesting column is induced to swing, thereby driving the contact-separation friction generator to swing up and down, causing the vertical contact-separation structure within the contact-separation friction generator to convert part of the swinging mechanical energy of the energy harvesting column into electrical energy, thereby achieving the purpose of fully collecting the vibration energy of the water flow and efficiently converting it into electrical energy, filling the current technical gap in the field of vortex-induced vibration in fluid energy collection. By providing an MFC piezoelectric sheet, its deformation can be utilized to convert part of the swinging mechanical energy of the energy harvesting column into electrical energy. By providing a turntable friction generator, the rotational mechanical energy of the support column can be converted into electrical energy, further reducing energy loss. The present invention realizes the efficient collection of water kinetic energy from all directions by simultaneously utilizing piezoelectric and triboelectric modules, and has high working efficiency.

The invention relates to the technical field of power system decentralized control, and discloses a multi-source information fusion control method for improving the stability of a power system, which comprises the following steps: acquiring a state error signal, injecting an active detection signal, extracting a self-response component and an orthogonal demodulation intermediate component of the active detection signal, calculating a power grid stiffness context parameter based on the self-response component, and calculating the stability of the power system. And generating a detection channel quality index based on the time stability of the intermediate component, and determining whether to fuse context parameters to carry out adaptive control or adopt preset default control parameters to carry out safe backspacing according to whether the quality index meets a preset threshold. The problem that oscillation is easily induced by context blindness in fixed parameter control is solved, a channel quality self-arbitration mechanism established by the method can actively back to a safety default parameter when sensing information is polluted, and the engineering safety of self-adaptive control is ensured.