Experimental investigation of feedforward control schemes of a flexible robot manipulator system

This paper presents experimental investigations into the applications of feedforward control schemes for vibration control of a flexible manipulator system. Feedforward control schemes based on input shaping and filtering techniques are to be examined. A constrained planar single-link flexible manipulator is considered in this experimental work. An unshaped bang-bang torque input is used to determine the characteristic parameters of the system for design and evaluation of the input shaping control techniques. The input shapers and filtering techniques are designed based on the properties of the system. Simulation results of the response of the manipulator to the shaped and filtered inputs are presented in time and frequency domains. Performances of the shapers are examined in terms of level of vibration reduction and time response specifications. The effects of derivative order of the input shaper on the performance of the system are investigated. Finally, a comparative assessment of the control strategies is presented and discusse

Information security culture in healthcare informatics: a preliminary investigation

Information security culture becomes an enabler towards an effective security practice. Human factors are recognised as one of the factors in addressing the issue of information security in healthcare informatics. Inculcating information security culture among healthcare practitioners is identified to be one of the solutions for a better security practice. Thus, identifying the issues and factors that influence information security culture are important. A preliminary investigation involving six healthcare professionals and academics have been carried out for better understanding on the critical factors that may influence the information security culture. In-depth interview method is chosen in this study. Thematic coding was conducted to characterise the themes and asses the factor that found to be influential. Results from the indepth interviews with healthcare expertise showed that four main themes may influence the degree to which information security may be cultivated. Security behaviour, security value, security awareness, and enforcement of security policy are the themes addressed by the key informants as the influential factors inculcating information security culture. This study also found that various level of healthcare professional exhibited different outcomes in information security culture. Findings from this study may provide guidance to the healthcare organisation to ensure their employee inculcate information security culture in holistic manner

River flow and stage estimation with missing observation data using Multi Imputation Particle Filter (MIPF) method

An advanced knowledge of the river condition helps for better source management. This information can be gathered via estimation using DA methods. The DA methods blend the system model with the observation data to obtain the estimated river flow and stage. However, the observation data may contain some missing data due to the hardware power limitations, unreliable channel, sensor failure and etc. This problem limits the ability of the standard method such as EKF, EnKF and PF. The Multi Imputation Particle Filter (MIPF) able to deal with this problem since it allows for new input data to replace the missing data. The result shows that the performance of the river flow and stage estimation is depending on the number of particles and imputation used. The performance is evaluated by comparing the estimated velocity obtained using the estimated flow and stage, with the measured velocity. The result shows that higher number of particles and imputation ensure better estimation result

Calibration of a drag tilt current velocimeter for an open channel application

Water is one of the prime elements responsible for life on earth with two thirds of the earth’s surface covered by it. Managing water resources effectively can promote conservation and make the best use of our limited water resources. Having knowledge about flow information on the river networks can be very beneficial for applications such as hydropower, transportation, irrigation, flood mitigation, water treatment, industrial and domestic needs. The development of simple and inexpensive instrument (<RM500) is to help researchers to produce and measure flows on spatial river at a very low cost. The analytic approximation was derived for giving relationship of the instrument’s tilting behavior on water velocity. Calibration process was held and the data are used to investigate the relationship between the measurement collected from the experiment and the known values. Analyzing the experiment results, it was concluded that the instrument tilting in response to the water velocities but not up to the expected known values. Random and systematic errors arise during calibration processes which contribute to the high uncertainties of the instrument. The documented experiments, procedure and facility used for the calibration are given in this paper. It is shown that the accuracy relationship of this instrument against the analytic approximation identified is 66.45%

Broadcast Control of Multi-Agent Systems for Assembling at Unspecified Point with Collision Avoidance

This paper presents a broadcast control problem for multi-agent systems to perform a motion-coordination i.e. assembling tasks without colliding into each other. In this paper, we use potential energy function for the collision avoidance where the agents will move away from the neighbor agents if they are reaching certain distance. In the simulation, the results show that the agents are successfully achieving the assembling task without colliding into each other

Enhancing the rheological properties and shale inhibition behavior of water-based mud using nanosilica, multi-walled carbon nanotube, and graphene nanoplatelet

Five different drilling mud systems namely potassium chloride (KCl) as a basic mud, KCl/partial hydrolytic polyacrylamide (PHPA), KCl/graphene nanoplatelet (GNP), KCl/nanosilica and KCl/multi-walled carbon nano tube (MWCNT) were prepared and investigated for enhancement of rheological properties and shale inhibition. Nanoparticles were characterized in drilling mud using transmission electron microscope (TEM) analysis. Mineralogical analysis of shale was examined by X-ray diffraction (XRD). Five shale plugs were prepared using compactor cell for the determination of shale swelling. Shale swelling was determined using the linear swell meter (LSM) for 20 hours. Results revealed that basic mud and KCl/polymer mud systems shows 30% and 24% change in shale volume. MWCNT, nanosilica and GNP were added separately in the KCl mud system. 0.1 ppb of each MWCNT and nanosilica showed 32% and 33% change in shale volume. However, when the shale was interacted with WBM containing 0.1 ppb of GNP, it was found that only 10% change in shale volume occurred. The results showed that the addition of nanoparticles in the KCl mud system improved the shale inhibition. API, HPHT filtrate loss volume, plastic viscosity (PV) and yield point (YP) were improved using GNP. It is learned from the experimental work that small concentration of KCl with GNP can mitigate shale swelling compared to the mud contains higher concentration of KCl and PHPA in WBM. Thus, GNP can be a better choice for enhancement of WBM performance

Experiments on the dynamics of density currents

Density currents occur when fluid of one density propagates along a horizontal boundary into fluid of a different density. In dam reservoirs, density currents are the main transport mechanism for the incoming sediments and they play an important role in redistribution of existing sediments. This paper aims to investigate velocity structure in the body of density currents. To this end, laboratory experiments were performed on density currents having various initial conditions and bottom slopes. Then, vertical velocity profiles were recorded in the body of density currents. The velocity structure of the currents was investigated by fitting equations to the wall and jet regions of the measured profiles, and the constants of the equations were yielded with R2 more than 0.80. Temporal and spatial evolution of density currents were also analysed to study the dynamics of the frontal region of the currents. It was observed that the currents having more bottom slope travel at a further distance. It was also found that 400% increase in the initial concentration of the currents can increase their frontal velocity up to 97%

ERGONOMICS ASSESSMENT OF WORKSTATION DESIGN IN AUTOMOTIVE INDUSTRY

The purpose of this study is to demonstrate the ability to interpret the various aspects of ergonomics contributions and influences in the manufacturing industry. The application of knowledge and understanding of the ergonomics theories and techniques in the manufacturing industry also will be demonstrated in this study. Besides that, this report will be able us to appreciate the ergonomic role in manufacturing industry and everyday context by showing the ergonomics contribution towards employees’ health and safety in the workplace and tangible or intangible profitability of the company. Adequate posture, work height, normal and maximum working areas are determined for the intended user population. The procedure for determining the workstation dimensions and layout has been explained. The importance of building a mock-up of the designed workstation and its evaluation with representative subjects is emphasized. A case problem (Final Inspection workstation) is discussed to illustrate the workstation design procedure

Detection of kidnapped robot problem in Monte Carlo localization based on the natural displacement of the robot

This article proposes a new method to detect the kidnapped robot problem event in Monte Carlo localization. The method is designed in such a manner that it can provide accurate detection across all time instances, whether the robot can still recognize part of the environment or is totally lost after kidnapping. The proposed method uses the sensor reading of the robot to determine if robot’s displacement at particular time instance is considered a natural displacement or not. A series of simulations are designed to measure the accuracy of detection and how it compares to other methods. The simulations show that the proposed method outperforms the methods of detection based on the weight of particles