Force Requirements Research Articles

Use of hydrogen as a source of clean energy

The increase in energy consumption is closely correlated with the continuous evolution of human society, which implies both the depletion of fossil fuels and the increase in pollution levels. One solution to these problems is to obtain electricity from renewable sources but also to use alternative fuels for car transportation. Within the paper, there are presented the necessary conditions for the design of hydrogen gas stations in accordance with the legal requirements in force regarding the protection to explosion.

Improvement and Application of Key Tools for Hydraulic Jet Fracturing

Aiming at the problems of poor reliability, low construction efficiency, and short service life of fracturing string in the application of hydraulic jet technology in Daqing Oilfield, targeted research has been carried out on key tools such as rubber cylinder, slip, and nozzle.A unidirectionally-sealing rubber cylinder adopting composite sealing method was designed. The rubber cylinder could bear the pressure of 80 MPa and temperature resistance of 150∘C under the setting force of 20 kN, with tensile strength increased by 23% and residual deformation rate less than 3%, showing good overall sealing performance and recovery. The finite element method was used to optimize the structural parameters, materials and process of the slip to increase the ability of slips to withstand alternating loads by 1.5 times. The arc-shaped nozzle was improved to reduce the pressure drop and increase the jet density. By improving the performance indicators of key tools, the optimized fracturing string could meet the construction requirements of low setting force, high sealing pressure difference, and repeated setting and fracturing. The improved technical string was applied to section 3459 of well 218 well in the field, with the success rate reaching 100%. The large-scale application of the improved fracturing string satisfied the construction requirements for large-scale volume fracturing of the for the 5 1/2" inch casing new well completion in the low-permeability and tight reservoirs of Daqing Oilfield.

The Link Between Organizational Agility And VUCA – An Agile Assessment Model

This paper summarizes the elements of agility listed in contemporary scientific literature and aligns them to the four different forces described by the acronym VUCA. There is a general consensus that organizational resilience and agility are crucial elements to gain sustainable competitive advantage especially since the arresting economic changes during the pandemic year 2020. There is little agreement though how precisely organizational agility responds to volatility, uncertainty, complexity, and ambiguity (VUCA). By systemization of frameworks and models from the literary sources the aim is to create a combined model. Consequently, the purpose of this paper is to develop a model that can practically be employed to evaluate the agile status quo of an organization. It should support practitioners to distinguish between the different requirements each part of the VUCA acronym requires. The design of this study is a conceptual paper which proposes a new corporate agility model with direct linkages to the requirements of VUCA forces. It derives from, and builds on, existing scientific literature while integrating a comprehensive set of existing agile frameworks. The result of this research is a model which defines distinct enablers, sensing capabilities, agile practices, and responses as answers to VUCA forces. It highlights that certain elements reinforce and link to each other to transform an entire organization agile. Surprisingly, leadership and strategy are not incorporated as elements but rather seen as conditions that subordinate the iterative learning approach of this model. Originality is given as the created model provides a set of elements leaders can implement or use to assess organizational agility. Furthermore, it supports how to deal with strategy and leadership in the transitional process. Relevance is given as during the worlds COVID-19 crises the economic and governments changes in terms of volatility and uncertainty were especially challenging for organizations.

Sizing and Simulation of Powertrain of Three-Wheeler Electric Vehicle

This research paper presents the study of designing, modelling and validating the results of simulation of powertrain of 3- wheeler electric vehicle with literature results. According to force and torque requirement at wheels, required power rating of motor is calculated. Indian driving cycle is used to calculate energy consumption by vehicle. Battery chemistry and sizing is selected according to energy requirement. According to requirement of power and constraints, type of motor is selected along with gear reduction calculation to achieve required torque and acceleration. For precise control of motor speed because of road profiles and traffic conditions control strategy is designed. All these subsystems are modelled on simulation platform and comparison with theoretical calculations will be carried out. The objective of this paper is to design, model and optimize the performance of electric vehicle in terms of powertrain and try to match the performance parameters with conventional IC-engine vehicle. This paper comprises of design in gelectric subsystems, creating control strategies for better performance and model-based simulation to check the performance

CFD investigation of the main rotor for an unmanned helicopter

The paper presents the CFD analysis of the main rotor of the unmanned helicopter model with a maximum take-off mass of up to 150 kg. The calculations were performed in ANSYS Fluent software. The results of the work are the relationship between the lift force generated by the main rotor as a function of the blade angle of attack. The results are presented for the three considered rotational speeds i.e. 1400, 1600, 1800 rpm. As the angles of the blades of attack increases, an increase in the rotor lift force, torque, and power requirement of the tested main rotor was observed. Additionally, the power required to drive a carrier rotor for the three speeds in question was calculated. Examined changes in the power requirement of the main rotor also showed a percentage increase when changing the α and increasing the rotational speed. The result based on the numerical calculations for three blades main rotor model were presented in tables and diagrams.

Effect of Stem Diameter, Moisture Content and Cutting Speed on Cutting Force for Groundnut Harvesting.

To design,and develop harvesting machines, the most important optimized parameter is the cutting force.The study was conducted to investigate the effect of stem diameter, moisture content, and cutting speed on the cutting force required for cutting groundnut stalks. The cutting force was measured using the reciprocating cutter bar test rig. Experiments were carried out at three levels of moisture content (40 - 47, 47 – 53, and 53 – 60 %) (wet basis), three levels of crop stem diameter (15- 17, 17 – 19, and 19- 21 mm) and three levels of cutter bar speed (0.80 – 0.90, 0.90 – 1.00 and 1.00 – 1.10 ms-1). The cutting force required for cutting groundnut crop stem was calculated for all the treatments. It was observed that increase in stem diameter, the cutting force increased by 19.83 % and increase in moisture content and cutter bar speed,the cutting force decreased by 37.57 %, and 34.11 %, respectively. The required cutting force (100 - 120 N) and energy (1.5 - 2.0J) was minimum at the cutter bar speed of 1.00 - 1.10ms-1 for 53 – 60 % moisture content, 15 - 17 mm stem diameter and they were maximum at cutter bar speed of 0.80 – 0.90 ms-1 (140- 160 N and 2.5 – 3.0 J)for 40 – 47 % moisture content, 19 – 21 mm stem diameter. The results showed that the cutting force requirement was increased with an increase in stem diameter and decreased with an increase in moisture content and cutting speed.

Seismic response modification factor for RC-frames with non-uniform dimensions

In existing seismic design codes, base shear is measured using the elastic force requirement divided by the strength reduction factor. This factor is used to take account of structures’ ability to dissipate energy by inelastic deformations. The main objective of this study is to determine the response modification factor (R) for RC frames with non-uniform spans and heights and compare the values to the Egyptian Code of Practice ECP-201. The case study consists of three groups of RC frames with detailed structural design: uniform spans and heights, non-uniform spans, and non-uniform heights. A sum of 30 systems of frames is analyzed by nonlinear static analysis, “pushover analysis,” using SAP2000 with FEMA-356 provisions to assess the R factor. Also, a comparison is held with R factor in the Egyptian code. It was found, considering the limitations mentioned in the conclusions, that R factor decreases with increasing the height of selected floors and it is greatly affected by the non-uniformity of span lengths. The listed values of R factor in the Egyptian code are conservative and not economic. Thus, it is recommended to include the non-uniformity in spans and heights, to get more accurate values of R factor.

Stud Shape and Joint Strength for Low Carbon Steel Joints fabricated by Friction Stud Welding with Low Load Force Requirement

Stud Shape and Joint Strength for Low Carbon Steel Joints fabricated by Friction Stud Welding with Low Load Force Requirement

Analysis of Double Seat Seal of Ultra High Pressure Flat Gate Valve

As an important part of the Christmas tree, the sealing performance of the flat gate valve is very important, and the O-ring seal is the most commonly used seal in the flat gate valve. Therefore, the research on O-rings is particularly important. For the flat gate valve with a single gate, its structure has gradually developed from a single seat seal to a double seat seal. This article mainly analyzes the sealing principle of the double seat in the ultra-high pressure flat gate valve and the influence of the pre-tightening force of the sealing ring on the sealing effect. Using finite element analysis software, a two-dimensional axisymmetric model of the double valve seat sealing structure was established to study the non-metallic sealing performance of the valve seat. The Mises stress, the maximum contact stress of the sealing surface, and the contact area of the sealing surface of the O-ring seal under different compression ratios are analyzed. The results show that when only the sealing performance and pre-tightening force requirements are considered, an O-ring with a larger wire diameter should be selected as much as possible. When considering the service life of the O-ring seal, the compression rate of the seal ring should not exceed 20%. Therefore, the selected seal ring wire diameter is 3.75mm within the recommended seal ring compression rate range.

MR Damper Modeling Performance Comparison Including Hysteresis and Damper Optimization

This research paper represents the analysis and simulation of semi-active suspension using non-linear modeling of the Magneto-Rheological (MR) suspension with consideration of the hysteresis behavior for a quarter car model. The research is based on the assumption that each wheel experiences the same disturbance excitation. Hysteresis is analyzed using Bingham, Dahl's, and Bouc-Wen models. This research focuses on simulation of passive, Bingham, Dahl, and Bouc-Wen models and analysis for the five road profiles. The desired damping force determines the optimum working conditions based on optimized critical design parameters. An integrated approach towards the numeric design optimization by computational methods has been used to find the optimum working conditions. The critical parameters of MR damper are determined, and multi-objective optimization is performed considering the pole length, piston radius, gap thickness, piston internal radius, piston velocity and coil current. Sensitivity analysis also is performed to identify the sensitive parameter in the MR damper geometry towards the damping force. Analysis shows that gap thickness is the most sensitive geometric parameter of the MR damper. Furthermore, the comparative study of the models for the highest comfort with less overshoot and settling time are executed. The Bouc-Wen model is 36.91% more accurate than passive suspension in terms of damping force requirements, has a 26.16% less overshoot, and 88.31% less settling time. The simulation of the Bouc-Wen model yields the damping force requirement to be 2150N which is 91% of the analytical results.

Prediction of microtunnelling jacking forces using a probabilistic observational approach

Microtunnelling is an increasingly popular means of locating utilities below ground. The ability to predict the total jacking force requirements during a drive is highly desirable for anomaly detection, to ensure the available thrust is not exceeded, and to prevent damage to the pipe string and/or launch shaft. However, prediction of the total jacking force is complicated by site geology, the use of a lubricated overcut, work stoppages, tunnel boring machine driving style and pipe misalignment. This paper introduces a probabilistic observational approach for forecasting jacking forces during microtunnelling. Gaussian process regression is adopted for this purpose which allows forecasts to be performed within a probabilistic framework. The proposed approach is applied to two recent UK microtunnelling monitoring projects and the forecasts are appraised through comparisons to predictions determined using design methods currently applied in industry. The results show that the proposed framework provides excellent forecasts of the monitored field data and highlights a significant opportunity to complement existing prescriptive design methods with probabilistic forecasting techniques.

Design and Modeling of a Parent Big STAR Robot Platform That Carries a Child RSTAR

In this paper we present a wheeled robot platform for child-parent robot collaboration. The new robot, named Big STAR (BSTAR), is fitted with a tail that can act as a ramp to carry and deploy a child RSTAR that can crawl between small cracks and underneath obstacles. Both robots possess sprawling capabilities inspired from insects, enabling them to transform their external geometry and dynamics to overcome a variety of obstacles. The BSTAR can travel at speeds of up to 1.4 m/s, carry payloads of more than five kilograms and travel over rough terrains. The collaboration between the two robots substantially increases their navigability and their capability to overcome obstacles. It increases their working distance and scouting area since the larger robot can act as a charging point for the smaller one. We first describe the design of the newly developed parent BSTAR robot and provide a kinematic and dynamic analysis that determines the force requirements of the robots when collaborating, followed by an evaluation of their mechanical and electrical requirements. We show that under multiple challenging scenarios the robot pair can successfully overcome a variety of obstacles.

Proposed minimum restoring force requirements for seismic isolated structures

In this research study, a new set of restoring force equations are proposed for seismic isolated structures subjected to far fault ground motions (FFGM) and near fault ground motions (NFGM). For this purpose, 110 FFGM and 49 NFGM are selected. Then, nonlinear time history analyses (NLTHA) of SDOF seismic isolated structures are performed using the selected ground motions to obtain their residual and maximum displacements. The analyses are repeated for an extensive range of parameters including peak ground acceleration, Ap, characteristic strength, Qd and post elastic period, Td, of the isolation system. Next, the variations of the residual and maximum displacements are plotted as functions of the various combinations of the parameters considered in the analyses. Then, nonlinear regression analyses are performed to formulate the residual and maximum displacements as functions of the parameters considered in the analyses. The developed equations are then used to formulate the upper limits of Td (restoring force equations) to ensure reasonable levels of residual and maximum isolator displacements. The developed restoring force equations are then compared with those of AASHTO and Eurocode-8 (EC-8) using the pool of residual and maximum displacement data obtained from NLTHA. It is observed that using the restoring force equations of AASHTO and EC-8 to check the design of seismic-isolated structures may, in some cases, produce unreasonably large levels of residual and maximum displacements. However, when the restoring force requirements proposed in this research study are applied, the residual and maximum displacements are observed to be within reasonable ranges.

Aircraft noise in residential areas, problems of measuring and evaluation

The intensity of civil aircraft flights elevates with the increase in the number of passenger and cargo transportation by air. Aircraft noise in the residential area near airports grows up too despite the use of low-noise aircraft models by airlines. This causes an augmentation in the number of complaints of the population in these areas. The Russian Federation’s normative and methodological documents requirements in force relating to measurements and assessment of noise in residential areas, including «aircraft noise», were analyzed. Their requirements in terms of measuring and assessing noise in residential areas, including “aircraft noise”, testifies to the insufficiency and ambiguity of these requirements. The main disadvantages are the lack of a clear definition of which sound event is considered «aircraft noise» and the lack of requirements for the duration of the reference time interval of noise measurement. The foreign experience of measuring and evaluating aircraft noise, as well as the effects of such noise on the population, are considered. This made it possible to determine the necessary and sufficient parameters for noise control in residential areas, including «aircraft noise». There were proposed both a definition of «aircraft noise» and the necessary parameters for its assessment. The necessary duration of the reference time interval for the measurement of normalized parameters was justified. Method for the normalized noise parameters in residential areas measurement using the chronograms of sound levels A was proposed. The technical implementation of such a method is presented. Proposed a definition of «aircraft noise» and measuring normalized parameters in the 15-minute reference time interval for inclusion in regulatory and methodological documents will help to eliminate ambiguity in measurements and noise assessment in residential areas.

Optimal 5R parallel leg design for quadruped robot gait cycle

This paper presents the design of optimal dimensions for a two degrees of freedom parallel mechanism used in quadruped for walking application. Serial linkages or open link mechanisms have less stiffness and poor dynamic performance, thus parallel mechanisms were developed. Many researchers have used symmetrical parallel leg for quadruped walking but force requirements are different in forward and return stroke, thus unsymmetrical parallel leg may be optimal. Using genetic algorithm, optimum link length values are obtained and the corresponding peak torque is also found.

Analysis of a 180-degree U-turn maneuver executed by a hipposiderid bat.

Bats possess wings comprised of a flexible membrane and a jointed skeletal structure allowing them to execute complex flight maneuvers such as rapid tight turns. The extent of a bat's tight turning capability can be explored by analyzing a 180-degree U-turn. Prior studies have investigated more subtle flight maneuvers, but the kinematic and aerodynamic mechanisms of a U-turn have not been characterized. In this work, we use 3D optical motion capture and aerodynamic simulations to investigate a U-turn maneuver executed by a great roundleaf bat (Hipposideros armiger: mass = 55 g, span = 51 cm). The bat was observed to decrease its flight velocity and gain approximately 20 cm of altitude entering the U-turn. By lowering its velocity from 2.0 m/s to 0.5 m/s, the centripetal force requirement to execute a tight turn was substantially reduced. Centripetal force was generated by tilting the lift force vector laterally through banking. During the initiation of the U-turn, the bank angle increased from 20 degrees to 40 degrees. During the initiation and persisting throughout the U-turn, the flap amplitude of the right wing (inside of the turn) increased relative to the left wing. In addition, the right wing moved more laterally closer to the centerline of the body during the end of the downstroke and the beginning of the upstroke compared to the left wing. Reorientation of the body into the turn happened prior to a change in the flight path of the bat. Once the bat entered the U-turn and the bank angle increased, the change in flight path of the bat began to change rapidly as the bat negotiated the apex of the turn. During this phase of the turn, the minimum radius of curvature of the bat was 5.5 cm. During the egress of the turn, the bat accelerated and expended stored potential energy by descending. The cycle averaged total power expenditure by the bat during the six wingbeat cycle U-turn maneuver was 0.51 W which was approximately 40% above the power expenditure calculated for a nominally straight flight by the same bat. Future work on the topic of bat maneuverability may investigate a broader array of maneuvering flights characterizing the commonalities and differences across flights. In addition, the interplay between aerodynamic moments and inertial moments are of interest in order to more robustly characterize maneuvering mechanisms.

Guest Editorial: Advanced Motion Control for Mechatronic Applications With Precision and Force Requirements

The articles in this special section focus on advanced motion control for mechatronic applications with precision and force requirements. Motion control is concerned with all the issues arising in the control of the movement of a physical device. This means that MC is not limited to the use of proper devices for sensing and actuation, in addition to suitable control algorithms, but it also deals with all the possible interactions of the controlled devices with the environment. This is the most remarkable aspect of MC, nowadays deployed in numerous mechatronic systems, especially those which are dynamically acting in heterogenous, time-varying, active, and human-accessible environments. With the progress of new technological solutions and design methods in the MC systems, like virtual sensors, human-machine and environmental interfaces and, above all, novel control strategies including observation, adaption, and precision and robustness enhancing techniques, the level of MC performance further raised in the last years. Especially, the mechatronic systems which have comprehensive application-specific requirements on the precision of controlled motion and the complying interactive forces are benefiting from the advanced MC techniques and related methods. Reduced energy consumption when inducing a controlled motion appears as an additional challenge.

Numerical Framework and Design Optimization of an Intrinsically Compliant 3-DOF Parallel Robot

Abstract Parallel robots are multiple degrees of freedom (DOFs) systems that are typically used in applications characterized by enhanced accuracy, rigidity, and large force requirements within a compact workspace. In the present research, an intrinsically compliant parallel robot with 3-DOFs, actuated using four pneumatic muscle actuators (PMA), is conceptualized, developed, and analyzed. Despite many benefits, parallel robots also offer certain challenges that arise from the highly coupled and nonlinear motion of their actuators. The small workspace of parallel robots has many singularities and solving a closed-form forward kinematics (FK) for its end-effector motion is complicated. The PMAs can provide intrinsically compliant robotic motions, however, since they are flexible, their unilateral actuation also poses constraints on the achievable DOFs. The present research focuses on analyzing kinematics and dynamics of the developed parallel robot incorporating the stiffness together with force closure analyses besides suggesting design improvements as a consequence of the singularity analysis. Design synthesis and multi-criteria optimization have been performed to obtain a robot design which may provide higher accuracies (near unity condition number), quick response to external wrench (stiffness and rigidity), and reduced actuator force requirements. SPEA2 (Improved Strength Pareto Evolutionary Algorithm) has been implemented to carry out the simultaneous optimization of design objectives and provide Pareto optimal design solutions.

Design and performance characterization of a soft robot hand with fingertip haptic feedback for teleoperation

ABSTRACT A soft robot hand with fingertip haptic feedback for teleoperation is proposed to perform complex tasks and ensure safe and friendly human-machine interaction. This robot hand can perform finger flexion/extension and abduction/adduction motions. A data glove is used to collect the hand joint angle data of the operator. Flexion sensors are embedded in the soft robot hand to monitor the bending angles of the actuators. Pressure sensors on the fingertips of the robot hand collect contact force data, and haptic feedback actuators located on the fingertips of the operator display the contact force to the operator. Characterization tests and teleoperation performance tests involving human participants are performed to prove the feasibility of the soft robot hand. The soft robot hand prototype satisfies the output force requirements and can meet 96.86% of the design requirements of the joint angles. The soft robot hand can be teleoperated to perform nine commonly used motions in daily operational tasks. The success rates of fingertip force discrimination, grasp, and pinch ability experiment are 100%, 95.00%, and 98.33%, respectively. The results of the experiment suggest that the soft robot hand with fingertip haptic feedback can perform complex tasks in teleoperation.

Effects of blades types on shear force and energy requirement of paddy stem

This study was aimed to determine of the shearing force and shearing energy of paddy stem as a function of blade type, blade-edge angle and cutting speed. The Karacadag white paddy variety was used as plant materials. Shearing properties were measured by a universal testing machine. Depend on measured shear force and cross-section area of paddy stem, energy values were calculated by measuring the surface area under the cutting force-deformation curve for each test separately. The tests were conducted at five blade angles, five loading speed with various three different type blades. The tests results showed that the shearing force, shearing strength, shearing energy, specific shearing energy and extension at maximum load were affected significant (p<0.01) by blade type, cutting angle and cutting speed. While the lowest values were determined at serrated 2 blade types, followed by the serrated 1 and flat-edge blade. The paddy stalk shearing force and energy values has increased with decrease in the blade edge angle from 90° to 50°. The highest force and energy values were measured at 90° cutting edge of blade as 25.47 N and 5.8 N cm. The effect of loading speed on the cutting forces, cutting strength, cutting energy and specific cutting energy were found significant (p<0.01). The shearing and energy has slightly decreased with an increase of blade cutting speed. While the highest values were found at 2 m s-1 loading speeds, the lowest values were found at 6 mm s-1 cutting speed.