scholarly journals Design and kinematics analysis of coordinated variable wheel-track walking mechanism

2020 ◽  
Vol 17 (4) ◽  
pp. 172988142093057
Author(s):  
Liguo Zang ◽  
Shaoqing Yang ◽  
Chongyou Wu ◽  
Xingyu Wang ◽  
Fei Teng
Keyword(s):  
High Mobility ◽  
Rolling Resistance ◽  
Front Wheel ◽  
Motion Simulation ◽  
Climbing Ability ◽  
Walking Mechanism ◽  
The Stability ◽  
Flat Ground ◽  
Slow Walking Speed ◽  
Wheel Track

Wheeled walking mechanism has the advantages of high mobility and low rolling resistance, but it is easy to sink and slip when working in soft and muddy terrain. Tracked walking mechanism has the advantages of high passability and stability, but it has the problems of difficult steering and slow walking speed. In order to make the walking mechanism possess a combination of passability, stability, and mobility, a coordinated variable wheel-track walking mechanism was designed. The coordinated variable triangle track can change the landing area through the deformation structure to improve the ability of the walking mechanism to adapt to different terrains. The kinematics equation of the wheel-track walking mechanism was established, and the front wheel steering angle equation during motion was derived. Based on RecurDyn software, the motion simulation of the walking mechanism was carried out under the conditions of straight walking and turning on the flat ground, climbing hillsides, and crossing ditches. The simulation results show that the coordinated variable wheel-track walking mechanism has the mobility of wheeled walking mechanism and the passability and stability of the tracked walking mechanism. The stability and climbing ability of the wheel-track walking mechanism was better when the coordinated variable triangle track in the stretch state, and the mobility and steering ability was better in the contraction state.

scholarly journals Barrier-Free Wheelchair with a Mechanical Transmission

2021 ◽  
Vol 11 (11) ◽  
pp. 5280
Author(s):  
Jongseok Lee ◽  
Wonhyeong Jeong ◽  
Jaeoh Han ◽  
Taesu Kim ◽  
Sehoon Oh
Keyword(s):  
The Elderly ◽  
Transmission System ◽  
Motor Drives ◽  
Mechanical Transmission ◽  
Link Structure ◽  
Second Mode ◽  
Important Means ◽  
The Stability ◽  
Flat Ground ◽  
Climbing Stairs

Wheelchairs are an important means of transportation for the elderly and disabled. However, the movement of wheelchairs on long curbs and stairs is restricted. In this study, a wheelchair for climbing stairs was developed based on a mechanical transmission system that rotates the entire driving part through a link structure and an actuator to change the speed. The first mode drives the caterpillar, and the second mode drives the wheels. When driving on flat ground, it uses landing gears and wheels, and when climbing stairs, it uses the caterpillar; accordingly, a stable driving is possible. The stability of the transmission is confirmed through stress analysis. The method used in our study makes it is possible to manufacture lightweight wheelchairs because a single motor drives both the wheel and caterpillar through the transmission system.

A novel path tracking approach considering safety of the intended functionality for autonomous vehicles

2021 ◽  
pp. 095440702110205
Author(s):  
Huiran Wang ◽  
Qidong Wang ◽  
Wuwei Chen ◽  
Linfeng Zhao ◽  
Dongkui Tan
Keyword(s):  
Autonomous Vehicles ◽  
Autonomous Vehicle ◽  
Coordinated Control ◽  
Steering System ◽  
Front Wheel ◽  
Path Tracking ◽  
Hierarchical Architecture ◽  
Automatic Steering ◽  
The Stability ◽  
Control Layer

To reduce the adverse effect of the functional insufficiency of the steering system on the accuracy of path tracking, a path tracking approach considering safety of the intended functionality is proposed by coordinating automatic steering and differential braking in this paper. The proposed method adopts a hierarchical architecture consisting of a coordinated control layer and an execution control layer. In coordinated control layer, an extension controller considering functional insufficiency of the steering system, tire force characteristics and vehicle driving stability is proposed to determine the weight coefficients of automatic steering and the differential braking, and a model predictive controller is designed to calculate the desired front wheel angle and additional yaw moment. In execution control layer, a H∞ steering angle controller considering external disturbances and parameter uncertainty is designed to track desired front wheel angle, and a braking force distribution module is used to determine the wheel cylinder pressure of the controlled wheels. Both simulation and experiment results show that the proposed method can overcome the functional insufficiency of the steering system and improve the accuracy of path tracking while maintaining the stability of the autonomous vehicle.

scholarly journals Dynamics and stability of skyrmions in a bended nano-beam

2021 ◽  
Author(s):  
Anruo Zhong ◽  
Xiaoming Lan ◽  
Yangfan Hu ◽  
Biao Wang
Keyword(s):  
Energy Cost ◽  
High Mobility ◽  
Bending Moment ◽  
Elastic Fields ◽  
Spintronic Devices ◽  
Bulk Stress ◽  
The Stability ◽  
Magnetic Skyrmions ◽  
Nontrivial Topology ◽  
A Current

Abstract Magnetic skyrmions are attracting much attention due to their nontrivial topology and high mobility to electric current. Nevertheless, suppression of the skyrmion Hall effect and maintaining high velocity of skyrmions with low energy cost are two major challenges concerning skyrmion-based spintronic devices. Here we show theoretically that in a nano-beam suffering appropriate bending moment, both Bloch-type and Néel-type skyrmions move with a vanishing Hall angle under a current density smaller than that required when the bending is absent. Moreover, bending alone can be used to move skyrmions, whose velocity is solved analytically from the Thiele equation. Generally speaking, inhomogeneous elastic fields affect the stability and dynamics of skyrmions, where the local stability is dominantly determined by the local bulk stress. These findings throw new light on how to drive skyrmions straightly with lower energy cost, which is vital for utilizing skyrmions as information carriers.

Steering and Stability of Single-track Vehicles

1951 ◽  
Vol 5 (1) ◽  
pp. 191-213 ◽  
Author(s):  
R. A. Wilson-Jones
Keyword(s):  
Lateral Force ◽  
Front Wheel ◽  
Slip Angle ◽  
Single Track ◽  
Motor Cycle ◽  
Low Mass ◽  
Low Speeds ◽  
The Stability ◽  
Straight Ahead

The author briefly states the elementary principles of equilibrium and claims that the stability of the conventional bicycle or motor cycle is automatic except at very low speeds. This is because the steering automatically turns in the direction in which the machine is leaning and returns to the straight ahead position when the machine is restored to the vertical. The achievement of these effects is largely due to the “trail” of the front wheel. The causes of “steering roll” and “steering wobble” and the purpose of the inclination of the steering head, are examined, as are the effects of high and low mass centres and of the rider leaning with and against the machine. It is shown how the elementary principles of steering apply to various types of vehicle, including single-track vehicles in which the necessary lateral force comes mainly from camber thrust rather than slip angle. The results are given of experiments on varying amounts of “trail”, and a method of measuring slip angles is described which is applicable to motor cycles. Finally, a method of indicating the direction of the torque applied to the handlebars when entering, holding, and leaving a bend is described.

Research on the Cornering Characteristics of Three-Axle Vehicle

2014 ◽  
Vol 945-949 ◽  
pp. 567-570
Author(s):  
Bo Xu ◽  
Sheng Min Cui ◽  
Xiang Yu Wu
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Front Wheel ◽  
Heavy Vehicle ◽  
Sideslip Angle ◽  
Motion Equations ◽  
Dynamic Steering ◽  
Angular Scale ◽  
Control Target ◽  
The Stability

A multi-axle dynamic steering technology was proposed to solve the steering stability and maneuverability problem of heavy vehicle. Two degrees of freedom linear steering-model and motion-equations of three-axle vehicle was established. Taking the zero sideslip angle as the control target and the proportional rear-front wheel angle as control method, we got the angular scale-factor equation and related matrix of the state space and transfer function. The MATLAB software was used to simulate the different steering modes stability steady-state and transient response. The results show that by using proportional control method the sideslip angle can be stabilized near zero and by using multi-axle dynamic steering technology the stability and maneuverability of the vehicle when steering can be improved effectively.

Experimental Study of the Dynamic Performance of a Cable with a Detecting Robot

2013 ◽  
Vol 433-435 ◽  
pp. 146-150 ◽  
Author(s):  
Feng Yu Xu ◽  
Zi Xin Chen
Keyword(s):  
Experimental Study ◽  
High Altitude ◽  
Vibration Amplitude ◽  
Dynamic Performance ◽  
Wind Load ◽  
Experimental Models ◽  
Highway Bridge ◽  
Climbing Ability ◽  
The Stability ◽  
Safe Performance

To analyze further the dynamic characteristics of the robotcable system, similar experimental models of cables on the Junshan Highway Bridge are constructed. To study the effect of high-altitude wind load on the safe performance of the cable and the robots climbing ability, transverse wind load is simulated and wind-load equivalent experiments on cable vibration are performed on the robot to simulate high-altitude conditions. Vibration amplitude and acceleration of the cable slightly increase under Grade 7 wind, which demonstrates the stability of the cablerobot system.

Dynamic Performance of Single-Axle Freight Trucks

1983 ◽  
Vol 105 (2) ◽  
pp. 71-74
Author(s):  
D. N. Wormley ◽  
P. A. Tombers
Keyword(s):  
Field Data ◽  
Critical Speed ◽  
Dynamic Performance ◽  
Design Parameters ◽  
Stability Field ◽  
Suspension Stiffness ◽  
The Stability ◽  
Freight Trucks ◽  
Selection Of ◽  
Wheel Track

An analysis has been developed to evaluate the stability of freight cars employing single-axle freight trucks. The analysis has been used to evaluate the influence of wheel/track contact geometry, suspension stiffness, and loading on truck stability. Field data resulting from measurement of a prototype car lateral axle accelerations have been used to identify car critical speeds as a function of suspension stiffness and loading. These data have agreed closely with the analytical calculations and provided a basis for selection of car design parameters to achieve desired values of critical speed.

A solution-processable host material of 1,3-bis{3-[3-(9-carbazolyl)phenyl]-9-carbazolyl}benzene and its application in organic light-emitting diodes employing thermally activated delayed fluorescence

2015 ◽  
Vol 3 (8) ◽  
pp. 1700-1706 ◽  
Author(s):  
Yoshitake Suzuki ◽  
Qisheng Zhang ◽  
Chihaya Adachi
Keyword(s):  
Light Emitting Diodes ◽  
High Mobility ◽  
Delayed Fluorescence ◽  
Organic Light Emitting Diodes ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Stability Of Solution ◽  
Organic Light ◽  
The Stability

The stability of solution-processed organic light-emitting diodes employing a thermally activated delayed fluorescent emitter was improved using a host with a high glass transition temperature and high mobility electron transport layers.

scholarly journals Structural Analysis of Avian Encephalomyelitis Virus Polyprotein for Development of Multi Epitopes Vaccine Using Immunoinformatics Approach

2021 ◽  
Vol 15 (1) ◽  
pp. 262-278
Author(s):  
Fatima Khalid Elhassan ◽  
Yassir A. Almofti ◽  
Khoubieb Ali Abd-elrahman ◽  
Mashair AA Nouri ◽  
Elsideeq EM Eltilib
Keyword(s):  
T Cells ◽  
Disulfide Bonds ◽  
Tertiary Structure ◽  
High Mobility ◽  
Dynamics Simulation ◽  
High Morbidity ◽  
E Coli ◽  
Encephalomyelitis Virus ◽  
The Stability ◽  
Chimeric Vaccine

Avian Encephalomyelitis (AE) is the disease caused by avian encephalomyelitis virus (AEV). The disease mainly affects young birds nervous system worldwide causing high morbidity and variable mortality rate in chicks and noticed egg dropping and hatchability in mature hens. Vaccination is the only way to control AEV infection since there is no treatment yet to the avian encephalomyelitis. This study aimed to use immunoinformatics approaches to predict multi epitopes vaccine from the AEV polyprotein that could elicit both B and T cells. The vaccine construct comprises 482 amino acids obtained from epitopes predicted against B and T cells by IEDB server, adjuvant, linkers and 6-His-tag. The chimeric vaccine was potentially antigenic and nonallergic and demonstrated thermostability and hydrophilicity in protparam server. The solubility of the vaccine was measured in comparison to E. coli proteins. The stability was also assessed by disulfide bonds engineering to reduce the high mobility regions in the designed vaccine. Furthermore molecular dynamics simulation further strengthen stability of the predicted vaccine. Tertiary structure of the vaccine construct after prediction, refinement was used for molecular docking with chicken alleles BF2*2101 and BF2*0401 and the docking process demonstrated favourable binding energy score of -337.47 kcal/mol and -326.87 kcal/mol, respectively. Molecular cloning demonstrated the potential clonability of the chimeric vaccine in pET28a(+) vector. This could guarantee the efficient translation and expression of the vaccine within suitable expression vector.

scholarly journals A Genetic-Algorithm-Based Optimization Routing for FANETs

2021 ◽  
Vol 15 ◽  
Author(s):  
Xing Wei ◽  
Hua Yang ◽  
Wentao Huang
Keyword(s):  
Genetic Algorithm ◽  
Routing Protocol ◽  
High Mobility ◽  
Destination Node ◽  
Improved Genetic Algorithm ◽  
On Demand ◽  
Link Stability ◽  
Variation Operators ◽  
The Stability ◽  
Route Search

In view of the characteristics of high mobility of FANETs nodes, combined with the features of Topology-based class routing protocol on-demand search, a Genetic-algorithm-based routing (GAR) protocol is proposed for FANETs which based on improved genetic algorithm for FANETs route search, and it taking into account the link stability, link bandwidth, node energy, and other factors. GAR improves the selection, crossover, and variation operators of the genetic algorithm so that GAR can finally plan an optimized route from the communication initiating node to the destination node quickly using a smaller cost. The experimental results show that GAR can largely improve the throughput, reduce the delay and improve the stability of the network, which is more suitable for FANETs.

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