Vibration Dampening for UAVs

Mounting system for attaching mission equipment like cameras and sensors to drones that allows flexible configuration of the drone and equipment. It uses a specialized mount apparatus that connects to the drone body and provides a separate mount for the equipment. This allows swapping and upgrading mission equipment without replacing the drone. The mount apparatus has a unique frame shape with dampers between connected frames to absorb vibrations.

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Modular integration kit for positioning systems on vehicles, comprising a configurable foundation plate, a dampened bolting structure, and a modular vibration isolation assembly. The foundation plate attaches to the positioning system, while the dampened bolting structure secures payloads. The vibration isolation assembly, comprising bayonet-style shock absorbers, connects the foundation plate and bolting structure to dampen vibrations. The kit is adaptable to various turret configurations and sizes, and can be used with sensitive payloads such as optics and weapons systems.

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Vibration isolator strut for spacecraft components like reaction wheels that provides isolation during launch and stable control afterward. The strut has a shaft with stops at each end that engage cavities to limit overload. Springs between the shaft ends isolate vibrations. A damper between the springs further dampens vibrations. The strut design allows high force launch loads to stop at the stops, then flex and damp after launch.

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Unmanned aerial vehicle (UAV) with soft arm propulsion vectoring that enables safe navigation around obstacles and minimizes damage. The UAV features flexible arms that bend upon collision, cushioning impacts while actively decelerating the contact. The arms are integrated into a propeller housing that houses a ducted fan, enhancing thrust efficiency while maintaining safety against environmental collisions. This innovative design enables the UAV to safely operate in environments where traditional hard-point protection would compromise maneuverability.

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Abstract Vibration is a very common phenomenon in helicopter flight, and its main source is the combined excitation force on the paddles as they rotate. In order to attenuate this harmful phenomenon, helicopter paddles are usually fitted with vibration absorbers. The helicopter rotor blade root single pendulum vibration absorber is a typical passive control type dynamic vibration absorber, which has a better vibration absorbing function, but also has certain difficulties in dynamics analysis. In this paper, a linearized dynamics analysis of the single pendulum vibration absorber is carried out, and a dynamics model of the paddle root single pendulum vibration absorber coupled with the paddle blade is established; a typical helicopter rotor system model is constructed by using Matlab, and further modeling and simulation comparisons are carried out by using ADAMS. According to the results of simulation and analysis, the unidirectional vibration level of the rotor hub can be reduced by 85% after the paddle root single pendulum absorber is installed, and the error with the theoretical an... Read More

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Abstract The delivery of medical products by drone is potentially game-changing and promises increased speed, particularly when trying to service hard to reach rural areas, and reduced carbon emissions. However, this raises a number of questions, including the effects of flight on the stability of medical products and how this can be mitigated through the design of appropriate packaging. The aim of this study was to design and experimentally evaluate a medical goods package capable of mitigating the vibration experienced during transportation by drone. Two proposed designs have been developed that feature coil spring and wire rope isolators. Transmission of vibration by these prototype packages, together with an industry-standard product, was measured both in the laboratory and in transportation trials. The prototype packages reduced transmitted vibration by a factor of six during drone flight tests but performed slightly worse when transported by car since road inputs occur at characteristically lower frequencies. The prototypes are significantly heavier than the standard product wh... Read More

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The advancement of sensor, actuator, and flight control technologies has increasingly expanded the possibilities for drone utilization. Among the technologies related to drone applications, the vibration isolator technology for payload has a significant impact on the precision of optical equipment in missions such as detection, reconnaissance, and tracking. However, despite ongoing efforts to develop vibration isolators to mitigate the impact of vibrations transmitted to optical equipment, research on drone-specific natural frequencies and payloads has been lacking. Consequently, there is a need for research on vibration isolators tailored to specific drone types and optical equipment payloads. This study focuses on exploring the correlation between the natural frequencies of drones and the weight of the payload, and proposes methods for developing and testing vibration isolators that consider both factors. To achieve this, the study measured the stiffness of vibration isolator rubbers and conducted cross-validation between random vibration tests and finite element method (FEM) analy... Read More

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Rotorcraft experience significant vibrations due to periodic aerodynamic forces and moments on the rotor blades and wings. Rotor torque damping is a novel vibration damping method which uses small torque perturbations from the main electric motor to reduce vibrations. The large inertial and aerodynamic rotor loading and relatively high frequency torque perturbations mean that the rotor speed changes are small, so the rotor thrust and flight control performance are not significantly affected. This paper investigates the application of electric motor torque control for damping structural vibrations of an aircraft. The structural dynamics of the aircraft are represented using a finite element model of a quad tiltrotor eVTOL. Using collocated angular rate feedback on all four rotors provides more than 10% damping in controllable modes. The RMS value of flap-wise angular rate can be reduced by 91% with less than 1.2 RPM rotor speed change in response to a 20% vertical step gust in airplane mode. For N/rev disturbance cancellation, an optimal controller is designed assuming known disturban... Read More

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Relevance. Mechanical vibrations are a common and technically important process that has a negative acoustic effect on human health and in some cases is a harmful production factor. In devices, the presence of vibration is caused by exciting influences of various physical nature: mechanical, electromagnetic, aerodynamic. The reason for their occurrence are defects in parts and assemblies, the technical principle of the ball bearing device, as well as the coincidence of the operating frequency of the device with natural frequency of the structural elements. Since it is technically impossible to completely eliminate the vibration activity of an electromechanical device, the actual topic of scientific research is the technical task of developing a damping device with determining its effectiveness to reduce the vibration activity of an electromechanical device, thereby minimizing the effects of concomitant harmful production factors on humans. To study this problem, a 3D model of the construction of a solid-state damper based on aluminum foam has been developed, according to which two la... Read More

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A vibration damping assembly for optical elements, comprising a base layer, a constraining layer, and a viscoelastic damping layer, wherein the constraining layer is positioned between the base layer and the damping layer, and the damping layer is positioned between the constraining layer and the optical element, to effectively reduce and/or eliminate ambient vibrations from transferring to the optical element.

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Vibration damping in aerospace structures can decrease the likelihood of failures and instabilities and improve passenger comfort. This paper introduces the novel idea of damping vibration using the electric proprotors on aircraft without compromising flight control. The equations of motion of a cantilevered beam with a propeller at the tip driven by an electric motor are obtained using Hamiltons principle, solved analytically in the frequency domain, and approximately in the time domain. Feeding back the beam tip angular rate to the motor torque is shown to asymptotically stabilize all transverse beam vibration modes. The overall vibration control consists of the inner rate feedback damping loop with an outer rotor speed control loop. Experimental frequency response and step response validate the models and show that the closed-loop damping in the first mode is three times higher than open loop with less than 1% rotor speed change for a 3% initial tip displacement. Theoretical results give good agreement with experiments. Parametric studies based on a 12 kg quadcopter indicate that... Read More

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An active vibration control system for rotor hubs of rotary-wing aircraft that reduces rotor-induced vibrations transmitted to the airframe. The system comprises a force generating device attached to the rotor hub, which rotates at the rotor speed and generates vibratory shear forces through high-speed unbalanced weights. The system uses feedback from vibration sensors to control the amplitude and phase of the generated forces, minimizing vibrations transmitted to the airframe.

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Vibration control techniques are various methods and devices designed to suppress unwanted vibrations, ultimately enhancing system performance and mitigating potential adverse effects. These techniques are widely applied in modern engineering, deducting the detrimental consequences of excessive vibrations, such as structural damage, noise generation, energy waste, and compromised functionality. The general classification of vibration control techniques includes passive, active, and semi-active control. Specifically, passive techniques like Tuned Mass Dampers (TMDs), active techniques like inertia mass actuators, and semi-active control devices such as magnetorheological dampers (MR dampers) are examined in this paper. Meanwhile, structural characteristics, mathematical models using formulas, and applications across diverse fields are analysed for each category. Moreover, efficiency analysis of all the discussed devices for vibration control is conducted through comparative analysis and detailed evaluation. In this case, valuable insights are gained regarding the overall effectiveness... Read More

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A rotor for a hover-capable aircraft, such as a helicopter, that reduces transmission of vibrations to the fuselage. The rotor includes a hub, a mast, and a vibration attenuation system comprising a mass suspended from the mast by an elastic system. The mass is connected to an electrical winding that interacts with a magnetic field generated by a permanent magnet, creating a Lorentz force that counteracts the vibrational forces. The system is designed to attenuate vibrations at multiple rotational speeds, including the first and second nominal speeds, while maintaining simplicity and cost-effectiveness.

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<title>Abstract</title> When the helicopter tail transmission shafting is over-critical, the shafting vibration intensifies, which restricts the overall performance of the helicopter. Smart spring support is an active damping device, which can effectively suppress the vibration of multi-span shafting. In this paper, the configuration and structure design of the smart spring support for multi-span shafting are studied, and its vibration-damping performance is verified by experiments. Firstly, based on the vibration reduction principle of the smart spring support, the vibration characteristics of the smart spring are analyzed. The motion equation of the smart spring support was established, the influence of configuration parameters on its vibration characteristics was analyzed, and the configuration parameters of the smart spring support were determined. On this basis, three configuration schemes of the smart spring support are proposed, the structural design of the smart spring support is carried out, and the structural parameters are determined. The shafting vibration reduction test ... Read More

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Vibration dampening is a term used in ergonomic, industrial, and electrical applications to minimize the system's kinetic energy. When vibration is attenuated, energy is delivered to the proper routes and noise propagation is diminished. The moment of the propeller and engine causes a drone to vibrate, with added complexity for drones because they are designed to have constant and carry fragile electronics. Investigating the uses of vibrational dampers and shock absorbers in UAVs utilizing several case studies based on material analysis, and different approaches. This report will assist us in reviewing previous research in this topic. In addition, the material properties of composite materials and shape memory alloys are being compared. Shape memory alloys have elastic characteristics and can restore their original shape.

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In order to reduce vibration from the source of the vibration of the helicopter and improve the efficiency of the damping of vibration, a propeller hub top mounted vibration damping actuator system and its position loop decoupling control strategy are proposed in this paper. By decoupling the position difference and average value of permanent magnet synchronous motors (PMSMs), high-precision servo control of the amplitude and phase of output force is achieved. The parameters of position loop are designed by small-signal modeling and root-locus stability analysis, and the effect of the vibration damping of the system is verified by simulation.

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Rotor for a hover-capable aircraft, comprising a hub with a plurality of blades, a mast, and a vibration attenuation system. The system includes a plurality of mass units, each comprising two masses connected by a belt and pulley system, which rotate about the mast axis. The masses generate centrifugal forces that counteract vibratory loads transmitted to the mast, thereby reducing transmission of vibrations to the fuselage.

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Vibration isolation system for concentric cylindrical structures, comprising at least three coaxially adjacent toroidal elements: an inwardly contiguous non-resilient element, an outwardly contiguous non-resilient element, and a noncontiguous resilient element. The resilient element is interposed between the non-resilient elements and attached to both, providing vibration isolation and damping along two axes while allowing axial movement.

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A real-time vibration monitoring system for unmanned aerial vehicles (UAVs) that detects and responds to abnormal vibration conditions. The system comprises vibration sensors installed at critical points on the UAV, a data acquisition module, a strategy determination module, and an operation execution module. The system continuously monitors vibration data, compares it against predefined thresholds, and implements protective actions based on the severity and location of the vibration anomalies.

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