Research on Hysteresis Modeling and Compensation Method of Giant Magnetostrictive Force Sensor

Linearity is an important index for evaluating the performance of various sensors. Under the Villari effect, there may be some hysteresis between the input force and the output voltage of a force sensor, meaning that the output will be multivalued and nonlinear. To improve the linearity and eliminate the hysteresis of such sensors, an output compensation method using a variable bias current is proposed based on the bidirectional energy conversion mechanism of giant magnetostrictive material. First, the magnetization relationship between the input force, bias current, and flux density is established. Second, a nonlinear neural network model of the force-magnetization hysteresis and a neural network model for the compensation control of the force sensor are established. These models are trained using the magnetic flux density-force curve and the magnetic flux density-current curve, respectively. Taking the optimal linearity as the objective function, the bias current under different input forces is optimized. Finally, a bias current control system is developed and an experimental test platform is built to verify the proposed method. The results show that the proposed variable bias current hysteresis compensation method enables the linearity under the return of the force sensor to reach 1.6%, which is around 48.3% higher than under previous methods. Thus, the proposed variable bias current method effectively suppresses the hysteresis phenomenon and provides improved linearity for giant magnetostrictive force sensors.

Spectral subtraction-based filter for experimental modal analysis under harmonics excitation force

In modal analysis, measurement of input force and vibration response are crucial to accurately measure the transfer function of the structure. However, under operating condition, the force induced by operating machinery is impossible to be measured due to the sensor placement issue. In this case, the ambient response induced by the operating force should be suppressed to minimize the error in the Frequency Response Function (FRF) calculation. This paper presents the utilization of a modified spectral subtraction filter for ambient suppression. The introduction of effective ambient magnitude in gain function calculation has increased the efficiency of spectral subtraction filter. This parameter is calculated based on the phase information of the reconstructed artificial ambient response. The measurement using EMA was carried out on a motor-driven structure to verify the proposed technique. Two sets of data under shutdown and running condition were recorded to observe the effect of ambient operating force. Under the operating condition, the measured FRF show the non-identical features at operating frequencies as compared to the baseline data. The utilization of filtering process shows the ambient features contained in the transfer function was effectively suppressed. The output of filtering algorithm could provide an alternative option to perform EMA procedure under running condition.

DESIGNING AN UPPER STAGE STEERING SYSTEM FOR A FORMULA FSAE CAR

The objective of this work is to design an upper stage steering system for the Formula FSAE car “Omega” that will effectively translate driver input force to the rack and pinion. The system consists of a steering wheel, steering shafts, universal joints, a quick release mechanism, and connection points to the car. Critical loads have been determined, and the final design has been validated using finite element analysis to ensure the safety of the assembly during normal operation and worst-scenario cases. The design key factors were performance, weight, cost, ergonomics, maintainability, manufacturability and reliability.

Large-Scale Lever-Based Triboelectric Nanogenerator for Sensing Lateral Vibration and Wrist or Finger Bending for Controlling Shooting Game

With advances in internet of things technology and fossil fuel depletion, energy harvesting has emerged rapidly as a means of supplying small electronics with electricity. As a method of enhancing the electrical output of the triboelectric nanogenerator, specialized for harvesting mechanical energy, structural modification to amplify the input force is receiving attention due to the limited input energy level. In this research, a lever structure was employed for delivering the amplified input force to a triboelectric nanogenerator. With structural optimization of a 2.5 cm:5 cm distance ratio of the first and second parts using two lever structures, the highest electrical outputs were achieved: a VOC of 51.03 V, current density of 3.34 mA m−2, and power density of 73.5 mW m−2 at 12 MΩ in the second part. As applications of this triboelectric generator, a vertical vibration sensor and a wearable reloading trigger in a gun shooting game were demonstrated. The possibility for a wearable finger bending sensor with low-level input was checked using a minimized device. Enhanced low-detection limit with amplified input force from the structural advantage of this lever-based triboelectric nanogenerator device can expand its applicability to the mechanical trigger for wearable electronics.

ANALISIS DATA INPUT FORCE PADA SHOCK ABSORBER DENGAN STRAIN GAUGE UNTUK MENGETAHUI PEMBEBANAN AKTUAL PADA MOBIL

Dalam dunia desain otomotif, khusunya pada bagian bodi kendaraan, diperlukan struktur yang kuat guna menjamin desain yang akan dijual ke masyarakat akan kuat dan tahan lama terhadap berbagai macam medan jalanan [7]. Untuk mengetahui seberapa besar gaya yang terjadi pada bodi kendaraan, dilakukan pengukuran input force di jalan secara aktual untuk mengetahui beban aktual yang membebani bodi kendaraan mengunakan sensor strain gauge. Tujuan dari penelitian ini adalah menganalisis pembebanan aktual pada bodi mobil secara teoritis (simulasi) dan aktual (pengujian). Penelitian dilakukan dengan melakukan simulasi pembebanan pada mobil menggunakan software DCS-100A dan DAS 100-A kemudian juga dilakukan pengujian aktual yang timbul di jalan sehingga diperoleh data dari keduanya dan dilakukan analisis perbandingan. Dari penelitian ini diharapkan dapat diperoleh data besarnya gaya aktual yang timbul pada berbagai macam medan jalan. Untuk kemudian ini dijadikan target pengembangan produk.

Measuring force and impedance for the tapping machine

The standard tapping machine used for the ASTM and ISO tests does not require the test engineer to measure the input force in the system, instead, just relies on measuring the sound pressure level (SPL) output. However, the input force depends on the assembly itself being tested. The input force levels are lower for lightweight assemblies like hardwood floors as compared to heavyweight assemblies like concrete. Without knowledge of this input force, the output SPL levels cannot and should not be compared using the IIC (Impact Insulation Class) rating. In this work, we measured the input force levels for the same tapping machine on different floors. We also measured the floor impedance for different assemblies and their comparison is also shown. This work shows the importance of measuring input forces for the standard floor-ceiling assembly impact tests

Investigating the Effect of Viscous Yield Dampers on Concrete Structure Performance

Viscous dampers are one of the most effective devices in the energy consumption of the buildings. The passive hybrid system progressive applications cause each of the dampers to compensate for the weakness of the other system, thus increasing the efficiency of passive control of the structure. Speed-based viscous dampers will adjust the amount of depreciation force based on the acceleration and velocity entering the system. On the other hand, displacement-based surge dampers adjust the amount of depreciation force based on the displacement required. Therefore, considering the different performances of these two dampers, the effect of using both of them in one structure can be investigated. In this study, by combining these two dampers, the seismic behavior of concrete structures has been evaluated. To study them, 5- and 10-story structures have been designed using FE method and have been subjected to earthquake records. Historical analysis shows that the use of hybrid dampers reduces the amount of seismic input force to the structure and also the amount of floor drift is reduced due to the use of dampers and also the capacity of structures for these structures is increased. The results of the study show that the presence of dampers in the structure increases energy absorption and improves performance in the structure.

Electromagnetic Energy Harvester for Transportation Infrastructure Using Vehicle-Tread Force

We propose a novel electromagnetic energy-harvesting device (EHD) for structural health monitoring systems of transportation infrastructures. The EHD is embedded in the road surface and uses the tread force of cars as the input force when tires of cars pass over it. Because the input force is very fast, the proposed EHD can generate a large amount of energy. The footprint of the device is 20 × 20 mm, its height is 7.5 mm, and its volume is 2.4 cm3. We measured the energy generated when a bicycle passed over the EHD 34 times at various speeds between 5 and 15 km/h. Subsequently, we obtained the regression curve from the results, which showed the relationship between the bicycle speed and generated energy, and estimated the electric energy generated by car at higher speeds. The results showed that, even though the size of the EHD was small, electric energies of 100 μJ, and 1.0 mJ could be generated at car speeds of 17 km/h, and 52 km/h, respectively.