Design, fabrication and application of magnetically actuated micro/nanorobots: A review

Magnetically actuated micro/nanorobots are typical micro- and nanoscale artificial devices with favorable attributes of quick response, remote and contactless control, harmless human-machine interaction and high economic efficiency. Under external magnetic actuation strategies, they are capable of achieving elaborate manipulation and navigation in extreme biomedical environments. This review focuses on state-of-the-art progresses in design strategies, fabrication techniques and applications of magnetically actuated micro/nanorobots. Firstly, recent advances of various robot designs, including helical robots, surface walkers, ciliary robots, scaffold robots and biohybrid robots, are discussed separately. Secondly, the main progresses of common fabrication techniques are respectively introduced, and application achievements on these robots in targeted drug delivery, minimally invasive surgery and cell manipulation are also presented. Finally, a short summary is made, and the current challenges and future work for magnetically actuated micro/nanorobots are discussed.

Characterization of In(Ga,Al)As/GaAs metamorphic heterostructures for mid-IR emitters by FTIR photoreflectance spectroscopy

Infrared photoreflectance (PR) spectra of In(Ga,Al)As/GaAs metamorphic heterostructures have been obtained using a novel photomodulation FTIR spectroscopy technique. An analysis of the PR spectra features allowed us to estimate the critical point energies corresponding to the direct interband transitions in various regions of the In(Ga,Al)As heterostructures, and distinguish the PR signals originating from Fabry-Perot interference. Observation of Franz-Keldysh oscillations originating from the InAlAs virtual substrate and an InGaAs waveguide layer has enabled determination of the built-in electric field intensities within the heterostructures. The obtained results open up possibilities for contactless control of free carrier concentration in In(Ga,Al)As/GaAs metamorphic heterostructures developed for growth of emitters of mid-IR spectral range.

Evaluation of 2D-/3D-Feet-Detection Methods for Semi-Autonomous Powered Wheelchair Navigation

Powered wheelchairs have enhanced the mobility and quality of life of people with special needs. The next step in the development of powered wheelchairs is to incorporate sensors and electronic systems for new control applications and capabilities to improve their usability and the safety of their operation, such as obstacle avoidance or autonomous driving. However, autonomous powered wheelchairs require safe navigation in different environments and scenarios, making their development complex. In our research, we propose, instead, to develop contactless control for powered wheelchairs where the position of the caregiver is used as a control reference. Hence, we used a depth camera to recognize the caregiver and measure at the same time their relative distance from the powered wheelchair. In this paper, we compared two different approaches for real-time object recognition using a 3DHOG hand-crafted object descriptor based on a 3D extension of the histogram of oriented gradients (HOG) and a convolutional neural network based on YOLOv4-Tiny. To evaluate both approaches, we constructed Miun-Feet—a custom dataset of images of labeled caregiver’s feet in different scenarios, with backgrounds, objects, and lighting conditions. The experimental results showed that the YOLOv4-Tiny approach outperformed 3DHOG in all the analyzed cases. In addition, the results showed that the recognition accuracy was not improved using the depth channel, enabling the use of a monocular RGB camera only instead of a depth camera and reducing the computational cost and heat dissipation limitations. Hence, the paper proposes an additional method to compute the caregiver’s distance and angle from the Powered Wheelchair (PW) using only the RGB data. This work shows that it is feasible to use the location of the caregiver’s feet as a control signal for the control of a powered wheelchair and that it is possible to use a monocular RGB camera to compute their relative positions.

Static characteristics of contactless converters of monitoring and control systems

The paper substantiates the need to use non-contact conversion and measurement of large direct currents using magnetic modulation contactless transducers of increased sensitivity for land reclamation, irrigation, industry, metallurgy and agriculture and water management in general, and the results of their design development are presented. It is shown that the developed converter, in contrast to the known ones, has increased accuracy and sensitivity, a technologically advanced design and low weight and dimensions with low material consumption and cost. Characteristics of information non-contact magnetic modulation converters statically are considered. It is shown that the value of the excitation value corresponds to a certain maximum value of the measured value. In this case, the maxima of the measured value, increasing in value with an increase in the excitation value, are shifted towards the increase in the measured value. The discrepancy between the experimentally and theoretically obtained static characteristics of the converter does not exceed 6 percent. The developed converter can be widely used in electrical systems in land reclamation and irrigation, in water supply, industry, railway transport, science, technology, and for checking electric meters at their installation site for contactless control of direct and alternating currents.

ВІДБИТТЯ УЛЬТРАЗВУКОВИХ ХВИЛЬ ВІД ДВОШАРОВОГО ПАКЕТУ ТЕКСТИЛЬНИХ МАТЕРІАЛІВ ЗІ ЩІЛЬНИМ ВЕРХНІМ ШАРОМ

Obtain and show in general terms the expression for the module of the complex reflection coefficient of ultrasonic waves from a two-layer package of textile materials with a dense first layer. The above is necessary for the possibility of research of contactless control of such materials. To analyze the process of reflection of waves from a controlled material, the method of superposition of sounding vibrations is used. In general terms, the expression for the complex reflection coefficient of ultrasonic waves from a two-layer package of textile materials with a dense first layer is shown. It is proved that taking into account the complete attenuation of the reflected waves in the layer of the first material, it is possible to simplify the basic expressions for the complex reflection coefficient from a package of textile materials. It is shown that the change in the amplitude of the reflected ultrasonic waves for the material presented in the work with a change in the thickness of its layers is very small. The change in the amplitude of the reflected waves for such materials mainly causes a dense first layer of package of textile materials. The dependences of the real and imaginary parts of the complex reflection coefficient of ultrasonic waves on a package of textile materials with a dense first layer are obtained, which will help analytically determine both the change in the amplitude of the waves and their phase shift caused by the interaction of these vibrations with the material. It is proposed to use the component expressions for the module of the complex reflection coefficient of ultrasonic waves, which will allow you to adjust the parameters of the contactless transducers for different two-layer package of textile materials with a dense surface layer. To ensure the possibility of determining a small change in the measured magnitude of the amplitude of the reflected ultrasonic waves from the two-layer package of textile materials with the first dense layer, you can use switching and modulation devices and transducers. This will eliminate the errors that may be associated with the non-identity of the measuring channels when determining a small change in the amplitude of the reflected ultrasonic waves.

ДОСЛІДЖЕННЯ ПРОХОДЖЕННЯ УЛЬТРАЗВУКОВИХ ХВИЛЬ КРІЗЬ ДВОШАРОВИЙ МАТЕРІАЛ ІЗ СКЛАДНОЮ СТРУКТУРОЮ ПРИ КОНТРОЛІ ЙОГО ТЕХНОЛОГІЧНИХ ПАРАМЕТРІВ

Investigate the passage of ultrasonic waves through a two-layer material with a complex structure with non-contact control of its technological parameters. A non-contact ultrasonic method was used in the work to control technological parameters of materials with a complex structure, which takes into account the attenuation of ultrasonic waves. It is substantiated that the attenuation of an ultrasonic signal for a material with significant pores during its transverse sounding can be neglected compared to attenuation in a material without through pores. The results of studies of the influence of the thickness of a material with pores on the amplitude ratios of ultrasonic waves are presented. The dependences of the amplitudes of ultrasonic waves are obtained, one of which passes through a two-layer continuous material, and the other passes through a two-layer material with pores, taking into account the dependence of their attenuation on the thickness of the material. In this work, we obtained the dependences of the phase shift of ultrasonic waves, which were reflected from a two-layer material without pores, and waves reflected from a two-layer material with pores, on the total thickness of the controlled material, if we compare the phase of these waves with incident vibrations. Also obtained are the dependences of the change in wave amplitudes over time for a pulsed ultrasonic signal passing through a controlled material. It is proposed to use a pulsed ultrasonic signal for operational non-contact control of technological parameters of bilayer materials with a complex structure. The analysis showed that the obtained expressions for pulsed ultrasonic signals that can interact with porous materials can be used to create new methods and means of non-destructive non-contact control of technological parameters of materials with a complex structure. The aforementioned will make it possible to create complex integrated and universal contactless control devices for various technological parameters for composite materials with pores, which today are subjected only to destructive contact control, which does not allow operational monitoring directly at the plant.

The Architecture of Functional Jurisdiction: Unpacking Contactless Control—On Public Powers, S.S. and Others v. Italy, and the “Operational Model”

Available accounts on jurisdiction, effective control, and the reach of human rights protections fail to provide a coherent construction that is principled and applicable across the board, within and beyond territorial borders. The “functional jurisdiction” model posited herein resolves these incongruities by looking at the normative foundation of sovereign authority overall, predicated on an exercise of “public powers” through which State functions are discharged, taking the form of policy delivery and/or operational action, whether inland or offshore, and which translates into “situational” control. Using the pending case of S.S. and Others v. Italy as an illustration, the article focuses on the sovereign-authority nexus that unites a specific state with a specific individual in a specific situation, triggering human rights obligations even through mechanisms of “contactless control” exercised via remote management techniques and/or through a proxy third actor. The role of extraterritorial operations, qua complex mechanisms of governance that implement broader policies with a planning, rollout and post-implementation phase, is central to this re-conceptualization, as is also the understanding that what makes control “effective” is its capacity to determine the material course of events and the resulting position in which those affected find themselves upon execution of the measure(s) concerned.