Modelling and Test of an Integrated Magnetic Spring-Eddy Current Damper for Space Applications

We present the design, manufacturing, and dynamical characterization of a mechanical suspension made by a passive magnetic spring and an eddy current damper integrated into a single device. Three configurations with 2, 3, and 4 permanent magnets axially distributed with opposite polarizations are designed, simulated, manufactured, and tested. Stiffness of 2410, 2050, 2090 N/m and damping coefficient of 5.45, 10.52 and 17.25 Ns/m are measured for the 2-, 3-, and 4-magnets configurations, respectively. The magnetic suspension provides good mechanical properties combined with excellent cleanness and high reliability, which is very desirable in mechanical systems for space applications.

Observation of phonon trapping in the continuum with topological charges

Phonon trapping has an immense impact in many areas of science and technology, from the antennas of interferometric gravitational wave detectors to chip-scale quantum micro- and nano-mechanical oscillators. It usually relies on the mechanical suspension—an approach, while isolating selected vibrational modes, leads to serious drawbacks for interrogation of the trapped phonons, including limited heat capacity and excess noises via measurements. To circumvent these constraints, we realize a paradigm of phonon trapping using mechanical bound states in the continuum (BICs) with topological features and conducted an in-depth characterization of the mechanical losses both at room and cryogenic temperatures. Our findings of mechanical BICs combining the microwave frequency and macroscopic size unveil a unique platform for realizing mechanical oscillators in both classical and quantum regimes. The paradigm of mechanical BICs might lead to unprecedented sensing modalities for applications such as rare-event searches and the exploration of the foundations of quantum mechanics in unreached parameter spaces.

Vibration Behaviour Control of a Fabricated One-Passenger Electric Vehicle with Either Mechanical or Air Suspension

Vehicle vibration transmission associated with the dynamic system depends on the frequency and direction of the input motion and the characteristics of vehicle suspension system and the seat from which the vibration exposure is received. A fabricated one-passenger electric vehicle equipped by a coil spring (mechanical) suspension system is introduced in this study. An air suspension system is used to replace the coil spring suspension system to improve ride comfort performance and intelligent classical adaptive neuro-fuzzy inference system controller is used to control the vehicle seat performance parameters. Accelerometers are mounted on the seat pan and seat base (floor) when measuring vertical acceleration. Data is frequently weighted according to standard BS 6841 in order to model the human response to vibration in terms of location and direction. The Simulink model is developed in Matlab software with the adaptive neuro-fuzzy inference system controller for the vehicle seat weighted vibration acceleration control. The results indicate that the predicted vibration acceleration can track the target vibration acceleration very well. Moreover, the values of the crest factor and kurtosis for the vehicle equipped by air suspension system are lower than those for the vehicle equipped by mechanical suspension system. Furthermore, the seat effective amplitude transmissibility for the fabricated vehicle with air suspension behaves lower value than that for mechanical suspension.

Quantification and Speciation of Trace Metals under Pollution Impact: Case Study of a Subarctic Lake

Monitoring the quantity and quality of metals in lake water is a major part of assessing water toxicity. A fundamental aspect of geochemical monitoring studies is the evaluation of the equilibrium distribution of metal speciation in water and the influence of environmental conditions on this process. It is important to understand the difference between the behavior of nanoparticles, dissolved particles, colloid particles, and suspended particles. This study involved environmental aquatic chemistry research and the assessment of the geochemical processes of metal speciation in an arctic lake in the metallurgical waste zone and other areas where natural processes prevail. Consecutive and parallel membrane filtration methods were used to compare the results of water analysis in Imandra Lake. The membrane pore sizes were 8, 1.2, 0.45, and 0.2 µm. The following filtrate characteristics were used: microfiltration-based mechanical suspension and oxidized contaminants (>8, 1.2, 0.45, 0.2, 0.1 μm), and ultrafiltration-based colloids, bacteria, viruses, etc. (less than 0.1 μm). Industrial effluents led to the formation of higher concentrations of elements (Ni, Cu, and Pb) in their labile forms. In the wastewater-mixing zone, the concentrations of most elements were evenly distributed in depth. In more distant areas, we found a significant increase in the concentration of elements in the near-bottom horizon in comparison with the surface water (Fe by more than three times). The obtained results showed that numerous elements had diverse distributions by speciation in the points located closer to the source of wastewater. This indicated the significant influence of the adsorption process on the system balance of elements such as Fe, Cu, and rare earth elements. The impact of the regional geochemical and anthropogenic speciation and the possible influence of climatic factors on the distribution of speciation were determined.

Амфибийные вездеходы на воздухоопорных гусеницах для освоения арктических шельфовых побережий

Амфибийные вездеходы на воздухоопорных гусеницах оказывают минимальное воздействие на поверхность грунта в арктической тундре, что является большим преимуществом этого типа транспортных средств, относя к их числу вездеходы грузоподъемностью до 150 т. Воздухоопорная гусеница конструктивно является промышленной конвейерной лентой, снабженной с наружной стороны надутыми пневматическими плицами большого диаметра. Воздушная подушка используется взамен металлической подвески. Большая площадь контакта пневматических плиц с поверхностью обеспечивает проходимость вездехода по слабому грунту, снегу или болоту в летнее время без повреждения тундрового дерна. Вездеходы на воздухоопорных гусеницах могут преодолевать уклон в 20 градусов, а также преодолевать береговой уклон. При форсировании пологих склонов вездеходы на воздухоопорных гусеницах в полтора два раза более эффективны, чем традиционные амфибии на воздушной подушке. Применение универсальных амфибийных транспортных средств на воздухоопорных гусеницах (ТСВГ) необходимо для освоения береговых территорий арктического шельфа.Amphibious all-terrain vehicle with the air-cushion caterpillars have minimal impact on the surface of ground in the arctic tundra, and this is a great advantage of this type of vehicles, referring to them the 150 t load capacity as well. The air-cushion caterpillar is manufactured conveyer track with the inflated pneumatic supports of large diameter on the outer side of the track. The aircushion is applied instead of the mechanical suspension rolls. The large area of pneumatic supports contact provides the passability of the vehicle in the weak ground, or snow or the marshland without the damaging of tundra turf in summer. The vehicles with the air-cushion caterpillars can go on the 20 degree slope as well as on the coast slope. For the overcoming of small slopes the vehicles with the air-cushion caterpillars are of 1.5 to 2 times more effective than that of the usual aircushion boats. The use of universal amphibious all-terrain vehicles with the air-cushion caterpillars (VACC) is of the demand for Arctic offshore coastal territories development.

Mode control of electro-mechanical suspension systems for vehicle height, levelling and ride comfort

This paper proposes a mode control algorithm of electro-mechanical suspension for vehicle height, attitude control and improvement of ride quality. The proposed control algorithm consists of mode selector, upper-level and lower-level controllers, and suspension state estimator. The mode selector determines the present driving mode using vehicle signals, such as longitudinal speed, steering wheel angle, accelerator pedal position, brake pedal position and vertical acceleration of wheels. The upper-level controller determines the desired suspension state using the present driving mode. The lower-level controller derives the desired stroke speed of the actuator in each suspension by linear quadratic control theory. The suspension state estimator has been designed using accessible sensor measurement by discrete-time Kalman filter theory. The control and estimation algorithms have been developed based on a novel reduced-order vehicle model that includes only the vehicle body dynamics. The model enables the observer to completely remove the effect of unknown road disturbance on the estimation error. The performance of the proposed control algorithm has been evaluated via computer simulation study. The simulation results show that the proposed control algorithm is effective at controlling the electro-mechanical suspension systems. The paper also shows that the considered actuator is suited for vehicle height and levelling control, but not for improvement of ride comfort, due to voltage input constraints.

The Performance Development of the Mechanical Suspensions Test Rig

Mechanical suspension test rig is much cheaper, but is can not meet the requirements of the suspension in-depth study. The reason is that the frequency and amplitude of the bench is immutable. According to the requirements of practical use, the frequency and amplitude control equipment is designed to arbitrarily change the vibration frequencies of the left and right wheels,and it can change the vibration amplitude of the wheels with a range of 5~12mm. It can meet the suspension test requirements.

Flatness-Based Open Loop Command Tracking for Quasistatic Microscanners

This paper describes a nonlinear command tracking scheme for an electrostatic laser scanning micromirror assembly. The results are based on an innovative gimballed comb transducer concept developed at the Fraunhofer Institute for Photonic Microsystems. The outer mirror axis is designed as a Staggered Vertical Comb (SVC) in out-of-plane configuration and it shall provide a quasistatic operation with large deflection angles for triangular trajectories. The challenges for trajectory design and open loop command tracking are determined by the inherently nonlinear transducer characteristics and the lightly damped mass-spring dynamics. In this paper a flatness-based trajectory design is presented that considers the nonlinear transducer dynamics as well as the nonlinear elastic mechanical suspension with model parameters derived from ANSYS analysis. The paper discusses design constraints and detailed design considerations and it shows proof of concept performance results based on experimental verification with a real microscanner assembly.

The Development of the Closed-Loop Control System for the Mechanical Suspensions Test Rig

Frequency and amplitude of the existing mechanical suspension performance test rig can not change. And it has signal function. Frequency changing devices and amplitude adjustment mechanism were designed on it by study. Frequency and amplitude of the improved test rig can change within a certain range. It has two control algorithms: fixed-frequency vibration and sweep vibration. And the used closed-loop control in the system ensures the reliability of the system. The results show feasibility and correctness of this control system by a large number of experiments. It improves the function of the test rig and decreases the cost of study.