scholarly journals A Versatile Aerial Manipulator Design and Realization of UAV Take-Off from a Rocking Unstable Surface

2021 ◽  
Vol 11 (19) ◽  
pp. 9157
Author(s):  
Hannibal Paul ◽  
Ryo Miyazaki ◽  
Takamasa Kominami ◽  
Robert Ladig ◽  
Kazuhiro Shimonomura
Keyword(s):  
Flight Time ◽  
Flat Surfaces ◽  
The Past ◽  
Link Mechanism ◽  
Novel Approach ◽  
Unstable Surface ◽  
Aerial Manipulator ◽  
Remote Environment ◽  
Parallel Link ◽  
Manipulator Design

UAVs are one of the fastest types of robots that can be deployed in a remote environment. Unfortunately, they have a limited flight time and therefore may need to stop occasionally in an unknown, uncontrolled area. However, conventional UAVs require flat and stationary surfaces for a safe landing and take-off. Some studies on adaptive landing approach for UAVs can be found in the past, but adaptive take-off from non-flat surfaces has not been discussed for the most part, yet. In this work, we discuss the problems associated with a conventional UAV take-off from non-flat surfaces and provide a novel approach for UAV take-off from a sloped or rocking surface. We also discuss the design of a novel multitasking three-arm aerial manipulator system with parallel link mechanism and achieve the above-mentioned task. With experiments, we show that the system can provide stability for a UAV landing on a rocking surface that allows for a safe take-off.

Extraordinary circumstances: Covid-19 – Italian Serie A scenario

2021 ◽  
pp. 175433712110192
Author(s):  
Milan Radojicic ◽  
Aleksandar Djokovic ◽  
Nikola Cvetkovic
Keyword(s):  
Cluster Analysis ◽  
Hierarchical Cluster Analysis ◽  
Hierarchical Cluster ◽  
Round Robin ◽  
The Past ◽  
Novel Approach ◽  
Round Robin Tournaments

Unpredictable and uncontrollable situations have happened throughout history. Inevitably, such situations have an impact on various spheres of life. The coronavirus disease 2019 has affected many of them, including sports. The ban on social gatherings has caused the cancellation of many sports competitions. This paper proposes a methodology based on hierarchical cluster analysis (HCA) that can be applied when a need occurs to end an interrupted tournament and the conditions for playing the remaining matches are far from ideal. The proposed methodology is based on how to conclude the season for Serie A, a top-division football league in Italy. The analysis showed that it is reasonable to play 14 instead of the 124 remaining matches of the 2019–2020 season to conclude the championship. The proposed methodology was tested on the past 10 seasons of the Serie A, and its effectiveness was confirmed. This novel approach can be used in any other sport where round-robin tournaments exist.

scholarly journals Development of a Four-legged Underwater Robot with Parallel-link Mechanism

2010 ◽  
Vol 45 (5) ◽  
pp. 731-736
Author(s):  
Takumi Yaginuma ◽  
Takasi Takesima ◽  
Etsurou Shimizu ◽  
Masanori Ito ◽  
Junnichiro Tahara
Keyword(s):  
Underwater Robot ◽  
Link Mechanism ◽  
Parallel Link

scholarly journals An Innovative Aerial Manipulator with Tandem Ducted Fans: Modeling, Control, and Simulation

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-24 ◽  
Author(s):  
Yibo Zhang ◽  
Wei Fan ◽  
Changle Xiang ◽  
Bin Xu ◽  
Tianfu Ai ◽  
...  
Keyword(s):  
Robust Controller ◽  
H Infinity ◽  
Domain Identification ◽  
Ducted Fan ◽  
Aerial Manipulator ◽  
Basic Performance ◽  
Aerial Vehicle ◽  
Manipulator Design ◽  
Confined Environment ◽  
Parametric Frequency

This paper proposes an innovative ducted fan aerial manipulator, which is particularly suitable for the tasks in confined environment, where traditional multirotors and helicopters would be inaccessible. The dynamic model of the aerial manipulator is established by comprehensive mechanism and parametric frequency-domain identification. On this basis, a composite controller of the aerial platform is proposed. A basic static robust controller is designed via H-infinity synthesis to achieve basic performance, and an adaptive auxiliary loop is designed to estimate and compensate for the effect acting on the vehicle from the manipulator. The computer simulation analyses show good stability of the aerial vehicle under the manipulator motion and good tracking performance of the manipulator end effector, which verify the feasibility of the proposed aerial manipulator design and the effectiveness of the proposed controller, indicating that the system can meet the requirements of high precision operation tasks well.

Transformational Leaders Help Their Employees Overcome Their Technophobia

2020 ◽  
Vol 16 (3) ◽  
pp. 70-85
Author(s):  
Odai Y. Khasawneh
Keyword(s):  
Technology Acceptance ◽  
New Technologies ◽  
New Technology ◽  
Transformational Leaders ◽  
Transformational Leader ◽  
The Past ◽  
Novel Approach ◽  
The Many ◽  
Narrow Context ◽  
Do So

The lack of technology acceptance in the workplace has haunted companies in the past and it seems that it will continue to do so in the future. One of the many variables that impact employees' acceptance of a new technology is technophobia; which previously has been studied within the narrow context of computers or few other technologies that are now outdated. In a novel approach, the current study examines employees' technophobia and how it impacts their technology acceptance. In addition, the moderating influence of transformational leadership is studied to determine whether that type of leadership would influence employees to overcome their technophobia. The data analysis confirms that technophobia and its subdimensions are still an issue that haunts the workplace. However, having a leader who's identified as a transformational leader can help employees overcome their technophobia. This study argues that it is vital for companies to understand the level and type of technophobia as well as what type of leadership their employees have before implementing any new technologies.

A sample path analysis of the M/M/1 queue

1989 ◽  
Vol 26 (02) ◽  
pp. 418-422 ◽  
Author(s):  
Francois Baccelli ◽  
William A. Massey
Keyword(s):  
Generating Functions ◽  
Queueing Networks ◽  
Transient Analysis ◽  
Bessel Functions ◽  
Sample Path ◽  
Laplace Transforms ◽  
Sample Path Analysis ◽  
Transient Distribution ◽  
The Past ◽  
Novel Approach

The exact solution for the transient distribution of the queue length and busy period of the M/M/1 queue in terms of modified Bessel functions has been proved in a variety of ways. Methods of the past range from spectral analysis (Lederman and Reuter (1954)), combinatorial arguments (Champernowne (1956)), to generating functions coupled with Laplace transforms (Clarke (1956)). In this paper, we present a novel approach that ties the computation of these transient distributions directly to the random sample path behavior of the M/M/1 queue. The use of Laplace transforms is minimized, and the use of generating functions is eliminated completely. This is a method that could prove to be useful in developing a similar transient analysis for queueing networks.

Machining Performance Evaluation of Robot Type Machine Tool Based on Forward Kinematics Model

2020 ◽  
Author(s):  
Akio Hayashi ◽  
Masato Ueki ◽  
Keisuke Nagao ◽  
Hiroto Tanaka ◽  
Yoshitaka Morimoto ◽  
...  
Keyword(s):  
Machine Tools ◽  
Geometric Model ◽  
Forward Kinematics ◽  
Machining Accuracy ◽  
Machining Performance ◽  
Kinematics Model ◽  
Link Mechanism ◽  
Conventional Machine ◽  
Type Machine ◽  
Parallel Link

Abstract Robot type machine tools with parallel link mechanism are characterized by the performance to change tool posture and machine wider range than conventional machine tools. It is realized by simultaneous multi-axis control of parallel link mechanism. However, there are some problems, it is difficult to identify and adjust alignment error. In addition, the machining performance is unidentified due to the rigidity is different from conventional machine tools. In this research, a geometric model is described and the forward kinematics model is derived based on the geometric model. Then, the machining tests were carried out to evaluate the machining accuracy by measured machined surface and the simulated motion of tool cutting edge based on proposed forward kinematics model.

Improving Privacy and Security of User Data in Location Based Services

2018 ◽  
Vol 9 (1) ◽  
pp. 19-42 ◽  
Author(s):  
Mohammad Yamin ◽  
Adnan Ahmed Abi Sen
Keyword(s):  
Peer To Peer ◽  
Location Based Services ◽  
Privacy And Security ◽  
Open Problems ◽  
The Past ◽  
Novel Approach ◽  
Cache Simulation ◽  
User Data ◽  
Improved Performance ◽  
Accuracy Of Results

Location Based Services (LBS) expose user data to malicious attacks. Approaches, evolved, so far, for preserving privacy and security, suffer from one or more anomalies, and hence the problem of securing LBS data is far from being resolved. In particular, accuracy of results vs. privacy degree, privacy vs. performance, and trust between users are open problems. In this article, we present a novel approach by integration of peer-to-peer (P2P) with the caching technique and dummies from real queries. Our approach increases efficiency, leads to improved performance, and provides solutions to many problems that have existed in the past. In addition, we offer an improved way of managing cache. Simulation demonstrates superiority of our approach over earlier ones dealing with both the ratio of privacy and that of performance.

Three DOF parallel link mechanism utilizing smooth impact drive mechanism

2002 ◽  
Vol 26 (3) ◽  
pp. 289-295 ◽  
Author(s):  
Takeshi Morita ◽  
Ryuichi Yoshida ◽  
Yasuhiro Okamoto ◽  
Toshiro Higuchi
Keyword(s):  
Drive Mechanism ◽  
Link Mechanism ◽  
Parallel Link

A Feasibility Study of the Material Removal Rate of the Conical End-Face of the Optical Fiber under Polishing

2014 ◽  
Vol 518 ◽  
pp. 19-24 ◽  
Author(s):  
Ying Chien Tsai ◽  
Guang Miao Huang ◽  
Jun Hong Chen ◽  
Inn Chyn Her
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
High Quality ◽  
Flat Surfaces ◽  
The Past ◽  
Beam Delivery

The surfaces of the microlenses at the conical end-faces of optical fibers require high quality to keep the best performance of laser beam delivery. The polishing parameters play an important role to get the best quality of the microlenses. Most of the past researches study on the polishing parameters of flat surfaces. In this study, the polishing area of the conical end-face of the optical fiber is varied during fabrication. The relation between removed volume and removed thickness is built to determine the material removal rate. An experiment is carried out and the results show that the first two spinning turns are much effective for polishing under the parameters of the experiment.

Force, Stiffness and Viscous Damping Control of a Stewart-Platform-Type Ankle-Foot Rehabilitation Assist Device with Pneumatic Actuator

2013 ◽  
Vol 25 (6) ◽  
pp. 897-905 ◽  
Author(s):  
Takayuki Onodera ◽  
◽  
Eiji Suzuki ◽  
Ming Ding ◽  
Hiroshi Takemura ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Force Control ◽  
Physical Therapists ◽  
Viscous Damping ◽  
Mean Square ◽  
Assist Device ◽  
Link Mechanism ◽  
Parallel Link ◽  
And Control ◽  
Ankle And Foot

The number of physically disabled people in need of rehabilitation is increasing. Unfortunately, there is a shortage of physical therapists specializing in such rehabilitation. This has increased the demand for rehabilitation assist devices that can lessen the burden of physical therapists. In this study, the authors develop a device that can assist in the rehabilitation of the ankle joint by employing a Stewart-platform (SP)-type parallel-link mechanism. With the SP-type parallel-link mechanism, it is possible to measure and control six degrees-of-freedom (DOFs) of ankle-foot movement during rehabilitation. Because the device enables the measurements of the ankle and foot, it is possible to calculate the instantaneous center of the ankle joint. In previous studies, the authors proposed methods to calculate and control the posture of the ankle and foot by an SP-type parallel-link mechanism and verified their accuracy. In this paper, the authors propose a method for force control using the device and also verify its accuracy. Using this device, the force acting on the ankle-foot can be controlled by six air cylinders. The force produced by a single air cylinder is determined by controlling the pressures in the extension and retraction directions. The accuracy of the force control method is verified for a single air cylinder and for the assist device when all six air cylinders are engaged. Results show that the accuracy of the single air cylinder has a mean square error of 0.24 N or less, while those for force control of the entire device are 4.2 N or less for parallel translation and 3.2 Nm or less for rotation. This demonstrates a satisfactory accuracy. To incorporate rehabilitation assistance by means of stiffness or viscous damping in the future, the authors also propose methods to control the coefficients of stiffness and viscous damping of the air cylinder and verify their accuracy. The mean square errors for the accuracies in controlling the coefficients of stiffness and viscous damping are 3.4 N/m and 1.4 Ns/m, respectively, thus verifying the validity of the proposed methods.

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