Magnetic Actuation Mechanism Research Articles

A Novel Caterpillar-Inspired Vascular Interventional Robot Navigated by Magnetic Sinusoidal Mechanism

Magnetic soft continuum robots (MSCRs) hold significant potential in fulfilling the requirements of vascular interventional robots, enabling safe access to difficult-to-reach areas with enhanced active maneuverability, shape morphing capabilities, and stiffness variability. Their primary advantage lies in their tether-less actuation mechanism that can safely adapt to complex vessel structures. Existing commercial MSCRs primarily employ a magnetic-pull strategy, which suffers from insufficient driving force and a single actuation strategy, limiting their clinical applicability. Inspired by the inchworm crawling locomotion gait, we herein present a novel MSCR that integrates a magnetic sinusoidal actuation mechanism with adjustable frequency and kirigami structures. The developed MSCRs consist of two permanent magnets connected by a micro-spring, which is coated with a silicone membrane featuring a specific notch array. This design enables bio-inspired crawling with controllable velocity and active maneuverability. An analytical model of the magnetic torque and finite element analysis (FEA) simulations of the MSCRs has been constructed. Additionally, the prototype has been validated through two-dimensional in-vitro tracking experiments with actuation frequencies ranging from 1 to 10 Hz. Its stride efficiency has also been verified in a three-dimensional (3D) coronary artery phantom. Diametrically magnetized spherical chain tip enhances active steerability. Kirigami skin is coated over the novel guidewire and catheter, not only providing proximal anchorage for improved stride efficiency but also serving similar function as a cutting balloon. Under the actuation of an external magnetic field, the proposed MSCRs demonstrate the ability to traverse bifurcations and tortuous paths, indicating their potential for dexterous flexibility in pathological vessels.

Portable microfluidic immunoassay platform for the detection of inflammatory protein biomarkers

A portable microfluidic platform uses a novel programmable magnetic actuation mechanism to process samples for sensitive detection of inflammatory biomarkers.

Research on Magnetic Actuation Mechanism and Kinematics of Soft Inspection Robot for HVDC Transmission Line

Research on Magnetic Actuation Mechanism and Kinematics of Soft Inspection Robot for HVDC Transmission Line

A magnetic soft robot with multimodal sensing capability by multimaterial direct ink writing

The all-in-one integration of materials, structures and sensors for next-generation magnetic soft robots is a promising avenue to interact with external surroundings. However, few surroundings-perceiving magnetic soft robots have been reported due to the lack of effective material design and fabrication process. Herein, a multimaterial direct ink writing (M2DIW) process is utilized to accomplish the one-step fabrication of magnetic soft materials and flexible sensing materials, completing seamless integrations between magnetic soft robots and flexible electronics. The magnetic actuation mechanism is discussed theoretically and multi-dimensional deformations of the robot are demonstrated experimentally. The seamless integration design of the multimaterial system endows the robot with sensing abilities for temperature (a linearity of 3.383 kΩ/°C), tactile (i.e., material recognition) and electrochemical (a detection limit of 0.036 mM for NaOH solutions) stimuli. As a proof-of-concept example, the experiment of targeted drug delivery by the robot is performed and the integrated sensors detect the surrounding concentration changes induced by the drug dissolutions for a quantitative evaluation of drug delivery. As such, the proposed magnetic soft robot integrated with multimodal sensing functions will shed light on the development of next-generation magnetic soft robots.

Magnetically Actuated Dynamic Iridescence Inspired by the Neon Tetra.

Inspired by the tropical fish neon tetra, we report a mechanism to achieve dynamic iridescence that can be magnetically tuned. This approach is based on the tilting of periodic photonic nanostructures, as opposed to the more common strain-induced color tuning. In this method, a periodic array of magnetic nanopillars serves as a template to guide the assembly of iron oxide nanoparticles when magnetized in a liquid environment. The periodic local fields induced by the magnetic template anchor the assembled particle columns, allowing the structure to tilt about the base when the angle of the applied field is changed. This effect emulates a microscopic "Venetian blind" and results in dynamic optical properties through structural coloration that is tunable in real time. The fabricated prototype demonstrates tunable reflectance spectra with peak wavelength shift from 528 to 720 nm. The magnetic actuation mechanism is reversible and has a fast response time around 0.3 s. This structure can be implemented on an arbitrary surface as dynamic camouflage, iridescent display, and tunable photonic elements, as well as in other applications such as active fluidic devices and particle manipulation.

Performance of a three-dimensional-printed microscanner in a laser scanning microscopy application

A magnetically actuated microscanner is used in a laser scanning microscopy application. Stress distribution along the circular-profiled flexure is compared with a rectangular counterpart in finite-element environment. Magnetic actuation mechanism of the scanning unit is explained in detail. Moreover, reliability of the scanner is tested for 3×106 cycle. The scanning device is designed to meet a confocal microscopy application providing 100 μm×100 μm field of view and <3-μm lateral resolution. The resonance frequencies of the device were analytically modeled, where we obtained 130- and 268-Hz resonance values for the out-of-plane and torsion modes, respectively. The scanning device provided an optical scan angle about 2.5 deg for 170-mA drive current, enabling the desired field of view for our custom built confocal microscope setup. Finally, imaging experiments were conducted on a resolution target, showcasing the desired scan area and resolution.

A Precise Magnetic Walking Mechanism

Inspired by magnetically actuated precision motion devices based on magnetic levitation and those based on elastic suspension, we devised a novel magnetic actuation mechanism, namely, a magnetic walking mechanism. This biped precision mechanism is a legged precision mechanism that consists of two elastically connected rigid legs. We designed the mechanism to be driven by one horizontal actuator and two vertical actuators, each comprising a permanent magnet and an air-core coil, and to produce both fine motion and walking motion. We discuss the underlying principles of force generation, leg actuation, fine motion, and walking motion. To demonstrate that both fine motion and walking motion can be created with this mechanism, we built and experimentally tested a two-legged walker. We successfully created a legged precision device capable of long-range fine motion and long-step walking motion based on a magnetic walking mechanism.

Bilateral Macro–Micro Teleoperation Using Magnetic Levitation

This paper introduces a novel magnetic-haptic micromanipulation platform with promising potential for extensive biological and biomedical applications. The platform has three basic subsystems: a magnetic untethered microrobotic system, a haptic device, and a scaled bilateral teleoperation system. A mathematical force model of the magnetic propulsion mechanism is developed, and used to design PID controllers for magnetic actuation mechanism. A gain-switching position-position teleoperation scheme is employed for this haptic application. In experimental verifications, a human operator controls the motion of the microrobot via a master manipulator for dexterous micromanipulation tasks. The operator can feel force during microdomain tasks if the microrobot encounters a stiff environment. The effect of hard contact is fed back to the operator's hand in a 20 mm × 20 mm × 30 mm working envelope of the proposed platform. Conducting several experiments under different conditions, rms of position tracking errors varied from 20 to 40 μm.

An experimental study of resistant properties of the small intestine for an active capsule endoscope

Use of the capsule endoscope (CE) in clinical examinations is limited by its passive movement resulting from the natural peristalsis of the gastrointestinal (GI) tract. Therefore, a locomotion mechanism is desirable for the next generation of capsule endoscope. Understanding the resistant properties of the small intestine is essential for designing a wireless magnetic actuation mechanism. In this paper, in vitro experiments were carried out to investigate the resistant force of the small intestine using 15 specially designed capsule prototypes and analysed the effect of the capsule dimension and moving speed. Segments of porcine small intestine were employed as a conservative model for the human intestine. When the capsules under experiment were moving at a speed of 0.5 mm/s, a resistant force of 20 to 100 mN were measured for the capsule diameter in the range of 8 to 13 mm. The force increased with moving speed. The intrinsic cause of the resistant force of the small intestine is discussed based on an analysis of the experimental data. It is believed that the viscoelastic properties of the tissue play an important role in the resistant characteristics of the small intestine.

A new method for boring of non-circular holes

A revolving electromagnetic actuation mechanism composed of an electromagnetic stator and an electromagnetic rotor has been developed for boring non-circular holes. The main component of the rotor is a flexure-hinged based flexible body. There are four pole-pair coils in the stator supplying actuation currents. The micro-displacement between the stator and rotor can be controlled by changing the currents applied in the pole-pair coils. Through linearization of the actuation force near the static action point, a linear relationship between the control current and the actuation force was established, and the synchronizing control method of the electromagnetic actuation mechanism is presented here. With two-factor analysis of the linearization error of the actuation force, the influences of control current and micro-displacement to the linearization error of the actuation force were studied. Then, the principle for designing the basic parameters of the magnetic actuation mechanism is put forward. The calibration of the mechanism indicates that the relationship between the micro-displacement of the rotor and the control current has linear characteristics in the required micro-displacement range. Simulation tests show that the turning radius of the rotor changes with the control current. The proposed mechanism can feasibly supply a controllable micro displacement to the boring bar.