scholarly journals Posture Dynamic Modeling and Stability Analysis of a Magnetic Driven Dual-Spin Spherical Capsule Robot

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 238
Author(s):  
Huiyuan Yang ◽  
Yongshun Zhang ◽  
Zhenhu Liu ◽  
Xu Liu ◽  
Guanxi Liu
Keyword(s):  
Angular Velocity ◽  
Magnetic Induction ◽  
Periodic Motion ◽  
Lyapunov Theory ◽  
Asymptotically Stable ◽  
Magnetic Torque ◽  
Stable Motion ◽  
Capsule Robot ◽  
Magnetic Induction Intensity ◽  
Spherical Capsule

In order to realize the intervention operation in the unstructured and ample environments such as stomach and colon, a dual-spin spherical capsule robot (DSCR) driven by pure magnetic torque generated by the universal rotating magnetic field (URMF) is proposed. The coupled magnetic torque, the viscoelastic friction torque, and the gravity torque were analyzed. Furthermore, the posture dynamic model describing the electric-magnetic-mechanical-liquid coupling dynamic behavior of the DSCR in the gastrointestinal (GI) tract was established. This model is a second-order periodic variable coefficient dynamics equation, which should be regarded as an extension of the Lagrange case for the dual-spin body system under the fixed-point motion, since the external torques were applied. Based on the Floquet–Lyapunov theory, the stability domain of the DSCR for the asymptotically stable motion and periodic motion were obtained by investigating the influence of the angular velocity of the URMF, the magnetic induction intensity, and the centroid deviation. Research results show that the DSCR can realize three kinds of motion, which are asymptotically stable motion, periodic motion, and chaotic motion, according to the distribution of the system characteristic multipliers. Moreover, the posture stability of the DSCR can be improved by increasing the angular velocity of the URMF and reducing the magnetic induction intensity.

scholarly journals Active Disturbance Rejection Control for Position Tracking of Electro-Hydraulic Servo Systems under Modeling Uncertainty and External Load

Actuators ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 20
Author(s):  
Manh Hung Nguyen ◽  
Hoang Vu Dao ◽  
Kyoung Kwan Ahn
Keyword(s):  
Angular Velocity ◽  
Disturbance Rejection ◽  
Lyapunov Theory ◽  
Tracking Performance ◽  
System Stability ◽  
Position Tracking ◽  
Parametric Uncertainties ◽  
Active Disturbance Rejection Control ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control

In this paper, an active disturbance rejection control is designed to improve the position tracking performance of an electro-hydraulic actuation system in the presence of parametric uncertainties, non-parametric uncertainties, and external disturbances as well. The disturbance observers (Dos) are proposed to estimate not only the matched lumped uncertainties but also mismatched disturbance. Without the velocity measurement, the unmeasurable angular velocity is robustly calculated based on the high-order Levant’s exact differentiator. These disturbances and angular velocity are integrated into the control design system based on the backstepping framework which guarantees high-accuracy tracking performance. The system stability analysis is analyzed by using the Lyapunov theory. Simulations based on an electro-hydraulic rotary actuator are conducted to verify the effectiveness of the proposed control method.

scholarly journals On a Periodic Solution of the 4-Body Problems

2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
Jian Chen ◽  
Bingyu Li
Keyword(s):  
Periodic Solution ◽  
Angular Velocity ◽  
Periodic Motion ◽  
Equilateral Triangle ◽  
Sufficient Conditions ◽  
Constant Angular Velocity ◽  
Necessary And Sufficient Conditions ◽  
The Other ◽  
The Masses ◽  
Necessary And Sufficient

We study the necessary and sufficient conditions on the masses for the periodic solution of planar 4-body problems, where three particles locate at the vertices of an equilateral triangle and rotate with constant angular velocity about a resting particle. We prove that the above periodic motion is a solution of Newtonian 4-body problems if and only if the resting particle is at the origin and the masses of the other three particles are equal and their angular velocity satisfies a special condition.

Microstructure and Properties of Cu-17Fe Alloy Aged Treatment in High Magnetic Field

2011 ◽  
Vol 194-196 ◽  
pp. 1270-1274
Author(s):  
Ke Ming Liu ◽  
De Ping Lu ◽  
Hai Tao Zhou ◽  
Sheng Fa Wen ◽  
Shi Yong Wei ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Magnetic Induction ◽  
Solid Solubility ◽  
Aging Treatment ◽  
Heat Treating ◽  
Hardness Tester ◽  
Energy Spectrometer ◽  
Magnetic Induction Intensity ◽  
Scanning Electron

Aging treatment of Cu-17Fe alloy was investigated by a vacuum heat treating furnace in high magnetic furnace. The microstructures were documented using scanning electron microscopy (SEM). The solid solubility of Fe in Cu matrix was analysed by energy spectrometer (EDS). The mechanical properties were measured with a Vickers hardness tester. The electrical conductivity was measured with a micro-ohmmeter. The results showed that high magnetic field can promote spheroidization of the Fe dendrites, the spheroidization intensifies and the solid solubility decreases with the increasing magnetic induction intensity of the high magnetic field exerted to the alloy, the solid solubility of Fe is minimum when the magnetic induction intensity is 10T at 500°C during precipitation. And Cu-17Fe alloy has a good strength/conductivity combination of 110Hv/63%IACS after aging treatment of 10T at 500°C for 1h.

Torques for Electromechanical Integrating Toroidal Drive

2005 ◽  
Vol 219 (8) ◽  
pp. 801-811 ◽  
Author(s):  
L Xu ◽  
J Huang
Keyword(s):  
Magnetic Induction ◽  
Electromagnetic Theory ◽  
Limit Value ◽  
Load Carrying ◽  
Tooth Number ◽  
Electric Parameters ◽  
Magnetic Induction Intensity ◽  
Driving Torque ◽  
Electromechanical Coupled ◽  
Periodic Changes

In this study, an electromechanical integrating toroidal drive is proposed and its operating principle is introduced. The equations of electromechanical coupled force and the rotor torque for the drive are given by means of electromagnetic theory and mechanical principle. The influenced factors of the rotor torque are analysed and their influences are obtained. There are periodic changes in the rotor torque and the change mainly depends on the tooth number of planet. The changes of the rotor torque along with mechanical and electric parameters of the drive and the limit-driving torque of the drive are presented. The limit driving torque is influenced by rotating angle of the planet and other factors. The minimum limit value decides the load-carrying ability of the drive. The equal-limit torque conditions between planet-worm and planet-stator are discussed. In order to obtain the equal-limit torque, a deterministic relation should be met among the current of the worm, the magnetic induction intensity of the permanent magnet stator, and the airgap thickness.

Simulation Research on the Magnetic Field of the Positioning Permanent Magnet for MEMS inside Human Body Based on Ansoft

2014 ◽  
Vol 596 ◽  
pp. 67-71
Author(s):  
Xiu Quan Liu ◽  
Yan Hong Li
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Magnetic Dipole ◽  
Human Body ◽  
Magnetic Induction ◽  
Dipole Model ◽  
Magnetization Direction ◽  
Simulation Research ◽  
Magnetic Induction Intensity ◽  
The Magnetic Field

the magnetic dipole model of the cylindrical permanent magnet was introduced. Then, based on Ansoft software, the simulation model of the cylindrical permanent magnet was established, and the influence of some parameters, such as the height, radius and magnetization direction on the magnetic induction intensity ,were studied; at the same time, under these two models the calculation was compared, the result shows the the magnetic dipole model is applied on condition that distance is nine times greater than the cylindrical permanent magnet size.

scholarly journals DESIGN OPTIMIZATION AND PERFORMANCE TEST OF MAGNETIC PICKUP FINGER SEED METERING DEVICE

2021 ◽  
pp. 137-144
Author(s):  
Fei Liu ◽  
Zhen Lin ◽  
Dapeng Li ◽  
Tao Zhang
Keyword(s):  
Vibration Frequency ◽  
Magnetic Induction ◽  
Vibration Amplitude ◽  
Magnetic Force ◽  
Performance Test ◽  
Simulation Software ◽  
National Standard ◽  
Design And Optimization ◽  
Seed Metering Device ◽  
Magnetic Induction Intensity

As the core part of precision seeder, the performance of pickup finger seed metering device directly affects the seeding quality. Aiming at the problem that the traditional pickup finger seed metering device can be easily affected by the performance of spring material, and the reliability of spring decreases with the increase of service time, a magnetic pickup finger seed metering device is designed to open and close the pickup finger by magnetic force, so as to improve the stability of seed metering performance. Through the design and optimization of permanent magnet structure, cam structure and seed taking pickup finger structure, the magnetic force distribution of ring magnet is analysed by using ANSYS Maxwell magnetic simulation software. Under the working speed of 3.9km/h, the vibration frequency, vibration amplitude and magnetic induction intensity were selected for orthogonal test. The experimental results show that the optimal combination of factors is vibration frequency 6Hz, vibration amplitude 3.1mm and magnetic induction intensity 316.34mT. Under the condition of the combination of operation parameters, the seed arrangement performance is 91.7% of the qualified rate, 6.2% of the replant rate and 2.1% of the missed rate, which meets the requirements of the national standard for the performance of the seeder. This study can provide a reference for the optimization of the structure and the improvement of the seed metering performance of the pickup finger seed metering device.

Electromagnetic Nondestructive Testing Model and Surface Magnetic Field Analysis for Circumferential Cracks on Metal Rod

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Feng Jiang ◽  
Shulin Liu ◽  
Shaojie Xin ◽  
Hongli Zhang
Keyword(s):  
Magnetic Field ◽  
Analytical Model ◽  
Magnetic Induction ◽  
Crack Depth ◽  
Field Analysis ◽  
Surface Magnetic Field ◽  
Circumferential Crack ◽  
Inner Surface ◽  
Magnetic Induction Intensity ◽  
The Magnetic Field

Abstract In this paper, an analytical model for a metal rod with a coating layer is proposed to evaluate circumferential crack from the signals of the surface magnetic field. In the proposed model, magnetic vector equations for four regions of space were built, and series expressions of the magnetic field were proposed by the truncated region eigenfunction method. The calculation results can show the three-dimensional distribution of axial and radial magnetic induction intensities on the surface of a metal rod clearly. In addition, the analytical model is verified by using comsol finite element simulation, which also demonstrates that induced eddy currents on the inner surface of the metal rod with cracks appear to be propelled toward the inner layer of the metal rod and the presence of a circumferential crack directly causes a decrease in the induced eddy current on the inner surface of the rod. The results calculated from the analytical model indicated that the model is capable of providing an accurate variation in the magnetic field due to circumferential cracks at different depths. The analytical results showed that the radial magnetic induction intensity increases by 0.16 × 10−3 T, while the axial magnetic induction intensity decreases by 0.3 × 10−3 T as the crack depth increases from 0 to 3 mm.

Anti-plane fracture problem of three nano-cracks emanating from a magnetoelectrically permeable regular triangle nano-hole in magnetoelectroelastic materials

2020 ◽  
pp. 2150127
Author(s):  
Dongsheng Yang ◽  
Guanting Liu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Release Rate ◽  
Magnetic Induction ◽  
Surface Effect ◽  
Electric Displacement ◽  
Magnetoelectroelastic Materials ◽  
Electric Displacement Intensity Factor ◽  
Magnetic Induction Intensity

Based on the Gurtin–Murdoch surface/interface model and complex potential theory, by constructing a new conformal mapping, the anti-plane fracture problem of three nano-cracks emanating from a magnetoelectrically permeable triangle nano-hole in magnetoelectroelastic materials with surface effect is studied. The exact solutions of the stress intensity factor, the electric displacement intensity factor, the magnetic induction intensity factor, and the energy release rate are obtained under the boundary conditions of magnetoelectrically permeable and impermeable. The numerical examples show the influence of surface effect on the stress intensity factor, the electric displacement intensity factor, the magnetic induction intensity factor, and the energy release rate under two different boundary conditions. It can be seen that the surface effect leads to the coupling of stress, electric and magnetic field, and with the increase of cavity size, the influence of surface effect begins to decrease until it tends to classical elasticity theory.

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