Allowable Payload Research Articles

Analysis of Allowable Payload according to Key Factors in Cable Logging Systems

Analysis of Allowable Payload according to Key Factors in Cable Logging Systems

Watch the Next Step: A Comprehensive Survey of Stair-Climbing Vehicles

Stair climbing is one of the most challenging tasks for vehicles, especially when transporting people and heavy loads. Although many solutions have been proposed and demonstrated in practice, it is necessary to further improve their climbing ability and safety. This paper presents a systematic review of the scientific and engineering stair climbing literature, providing brief descriptions of the mechanism and method of operation and highlighting the advantages and disadvantages of different types of climbing platform. To quantitatively evaluate the system performance, various metrics are presented that consider allowable payload, maximum climbing speed, maximum crossable slope, transport ability and their combinations. Using these metrics, it is possible to compare vehicles with different locomotion modes and properties, allowing researchers and practitioners to gain in-depth knowledge of stair-climbing vehicles and choose the best category for transporting people and heavy loads up a flight of stairs.

Topology Optimization Design and Experiment of a Soft Pneumatic Bending Actuator for Grasping Applications

Soft pneumatic bending actuators are commonly used in robotic grasping applications and can be applied for handling both delicate and irregularlyshaped objects. Because these soft pneumatic actuators are typically embedded with multiple air chambers inside soft, thin structures, their maximum payloads are usually low compared to rigid designs of similar size. This article presents a soft pneumatic bending actuator design using a topology optimization procedure that can maximize the bending capability and thus increase the allowable payload of soft grippers that consist of multiple pneumatic bending actuators. After an optimum design is obtained, multiple identical actuators are prototyped through a molding process using a silicone rubber material. Both two-fingered and three-fingered soft grippers are developed using the topology-optimized pneumatic bending actuators. Experiments, including a bending angle test, an output force test, and a payload test, are conducted in this study,and the results are compared against the test results of the commercial SRT soft pneumatic actuator. The experimental results show that the bending angle for the developed bending actuator is 111 degrees on average of 10 tests at an input pressure of 50 kPa. The output force is 9.45 N at an input pressure of 80 kPa, while the maximum payloads of the two-fingered and three-fingered grippers are 2.66 kg and 5.12 kg, respectively.

Exploring the Physical Limits of Axial Magnetic Bearings Featuring Extremely Large Vertical Levitation Distances

This work provides an analytical method, based on the Ampèrian model of permanent magnets (PM), for a fast calculation of the magnetic flux density in three-dimensional space applying Biot–Savart law, and the calculation of the forces using Lorentz's law. The applied approach enables the characterization regarding forces, torques, and stiffnesses of the levitating PM for any arbitrary position in space. Furthermore, it permits the extension of the investigation to any shape and configuration of ironless magnetic bearings (MB). In order to demonstrate the simple use of the analytical model, in this article, the dimensions of an ironless axial MB employing PMs are optimized with a multiobjective Pareto analysis, which reveals the physical limits concerning maximum achievable levitation height with respect to given constraints on, e.g., the required force and tilting stiffnesses, and the MB robustness defined by the maximum allowable payload on the levitating magnet. Moreover, the optimized axial MB and a corresponding test bench are realized to validate the proposed model with experimental results. For the sake of completeness, it should be mentioned that in a later stage, the optimized MB can also be scaled with simple scaling laws if the demanded specifications, e.g., concerning desired maximum levitation height or payload capability, would have changed.

Optimization of UAV structure and evaluation of vibrational and fatigue characteristics through simulation studies

Unmanned Aerial Vehicles (UAV) is generic air vehicles that are significantly developed for military and civil purposes. In recent times, advancements in the field of UAVs are exceptional and tremendous. Nevertheless, numerous researches have been performed mainly to reduce the weight of the UAV structure. The flight time and allowable payload rely on the UAV structure's weight, which is considered a significant factor. Hence, in this paper, the UAV model's static structural behavior is cultivated utilizing the morals of Finite Element Analysis (FEA) to determine the total deformation and Von-mises stress. Three different polymer materials, namely Poly Lactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), and Polyamide (PA), are chosen for FEA analysis of 3D printed UAV structure. The thrust generated from the motors varies from 2 kg to 5 kg, and an evaluation of structural strength characteristics is performed. The FEA study has shown that maximum deformation and maximum stress are obtained at the propeller casings and the basement of the structure, respectively. After comparing the details on deformation and stress from all three materials, the research also reveals that PLA is the best material for conception. Furthermore, topological optimization is performed on the UAV structure to reduce mass and minimize stress without compromising mechanical strength. The vibrational and fatigue characteristics of optimized UAV structure is examined. The unified body of the UAV frame will reduce the assembly time and make manufacturing much more effortless.

Istraživanje redukcije njihanja korisnog tereta manipulacijom dužine kabla prilikom kretanja strele krana

This paper is focused on an investigation into the control dynamics of a boom crane through a study of guided payload pendulum motion with a non-uniformly rotating boom-driven pivot center and variable cable length. A time-optimal control problem was formulated and numerically solved with constraints on the allowable payload swaying value using JModelica.org freeware with Optimica extension. Solutions of the optimum speed problem for the dynamic model describing the movement of the payload from the initial position to the final position are found, taking into account the nonlinearities associated with the Coriolis force, and the change in cable length during the motion. Two cases are considered: with and without taking into account the constricts on the swaying value. It was found that taking into account the constricts on the swaying value leads to an overshoot of the phase variable length. The obtained results can be used for cargo transportation by crane in various fields: industry, construction, etc. The resulting control will allow a reduction in cargo transfer time, which will lead to an increase in labor productivity. It will also reduce the amount of payload swaying, which will reduce the likelihood of injury during loading and unloading operations. The model is nonlinear, and the Coriolis force and other nonlinearities are taken into account. The model is electromechanical; the characteristics of the electric motors of the tower and the winch are taken into account. A comparative analysis of the problem of optimal control with and without allowance for restrictions on the cargo swaying value is provided and differences in the control functions for each of these cases are defined. The optimal control, taking into account the change in rope length, allows the solution of practical tasks in moving the cargo, taking into account the presence of obstacles that arise on the way of the cargo.

Analysis of Elastic Motion Stability of Flexible Manipulator Arm Based on Roth Criterion of Control System

In order to study the elastic motion stability of flexible manipulator arm , to analyze the effect of the end position addition mass and rotary inertia on the elastic motion stability ,and to compute the maximum dynamic allowable payload , the physics model of a flexible manipulator arm is established , the differential equation of elastic motion of the flexible manipulator arm is solved using the method of the separation of time and space and the method of Laplace transformation , the dynamic model of flexible manipulator arm carried addition mass on its end position is established ,simplified and truncated using Lagrange equation . the state space expression and transfer function are established with the state variable and control input and output variable designated , the elastic motion stability rule is built upon and simplified using Roth criterion . The influence of the end position addition mass and articulation rotational inertia of flexible manipulator arm on its elastic motion stability is analyzed using the stability rule and the dynamic maximum allowable payload of flexible manipulator arm on its end position is computed in order to guarantee its elastic motion stability .

Analysis of Elastic Motion Stability of Flexible Manipulator Arm Based on Lyapunov Stability Theory

In order to study the elastic motion stability of flexible manipulator arm , to compute the maximum dynamic allowable payload , the partial differential equation of elastic motion of the flexible manipulator arm is solved using the method of Laplace transformation , the dynamic model of flexible manipulator arm carried addition mass on its end position is established ,simplified and truncated using Lagrange equation . the state space expression is established with the state variable and control input and output variable designated , the elastic motion stability rule is built upon and simplified using Lyapunov stability theory . The influence of the end position addition mass and articulation rotational inertia of flexible manipulator arm on its elastic motion stability is analyzed using the stability rule , and the dynamic maximum allowable payload of flexible manipulator arm on its end position is computed in order to guarantee its elastic motion stability . this study is important to the design of robot mechanical manipulator and corresponding drive control system .

Thermal Protection System and Trajectory Optimization for Orbital Plane Change Aeroassisted Maneuver

The aim of this paper was to identify, for a specific maneuver, the optimal combination between the trajectory and the associated heat shield configuration, namely the locations and thicknesses of the ablative and reusable zones, that maximize the allowable payload mass for a spacecraft. The analysis is conducted by considering the coupling between the trajectory's dynamics and the heat shield's thermal behavior while using a highly representative model of the heat shield. A global optimization procedure and original software were developed and implemented. The analyzed mission considers an aeroassisted transfer from two low Earth orbits with an assigned orbital plane change maneuver for a given delta wing vehicle equipped with a heat shield consisting of both ablative and reusable materials. The results indicate that the aeroassisted maneuver is more convenient than a full propulsive maneuver in the analyzed case, even considering the increased vehicle mass due to the presence of the heat shield.

Process development for electrocarboxylationof 2-acetyl-6-methoxynaphthalene

Electrochemical carboxylation of 2-acetyl-6-methoxynaphthalene to 2-hydroxy-2-(6-methoxy-2-naphthyl)propionic acid may be carried out in good yield (∼89% in the electrolysis; 75% as isolated dried product) in an undivided flow cell using lead as the cathode and aluminium as the dissolving anode. Dimethylformamide was found to be the best solvent for the reaction and low cost tetraethylammonium chloride hydrate is a good electrolyte for the system. The best conditions are those that increase carbon dioxide concentration although higher pressure seems to be more effective than low temperature. The reaction may be carried out with good yield at fairly high current density (1150Am−1) and higher current densities are likely attainable. The allowable payload is limited to around 10% because higher payloads (20%) resulted in solution too viscous to pump. Initially it was surmised that trace quantities of water would be detrimental to good yields in these reactions. However, it was found that small amounts of water (that associated with typical quaternary ammonium chloride salts) has the beneficial effect of eliminating the major byproduct which is formed in more nearly anhydrous solutions without resulting in formation of alternative byproducts. Process conditions were evaluated at 0.2L scale, then scaled up to 1L and finally 75L. The best results were attained in the 1L system, solvable operating problems limited the yield in the largest scale electrolysis.

Relationship between payload and speed in legged locomotion systems

The dependency of payload on vehicle operating speed, which is a problem peculiar to legged locomotion, is examined via a case study of a hexapod using wave gaits. The treatment presented is confined to systems using quasi-statically stable gaits. A set of closed-form analytic expressions describing the payload-speed relationship has been obtained. The solution is based on the assumption of equal leg compliances. The utility of such relationships lies in determining the allowable payload given the vehicle speed and weight or, conversely, in preplanning the payload to be carried and determining the maximum speed at which the vehicle can operate safely.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Power Limited Design Approach for Combatant Ships

ABSTRACTThe usual design approach for combatants is to select the combat system and ship performance parameters and then determine all of the ship characteristics including the power plant size. Described in this paper is an alternative design approach wherein the power plant and electrical plant are selected after a sustained speed is chosen. Then the hull design, propulsor, transmission system and the various other subsystems can be selected to maximize the payload. The payload items are selected to match the weight and space available. The implication of the hull, mechanical and electrical (HM&amp;E) selections are discussed. A series of examples is used to illustrate the importance of sustained speed, hull form, drag reduction approaches, propulsor and subsystem selection on payload size or combat system capability. The approach can also be used to assess the merits of various HM&amp;E technologies for increasing the size of allowable payload. Twenty technologies are assessed using this approach and compared to each other for payload weight and volume increases. Four power limited ship designs, all using two gas turbine engines for main propulsion power, are compared in detail as examples of the approach. The designs are compared and assessed using survivability and mission effectiveness analyses. This assessment may assist and guide future design efforts. The viability and value of the power limited approach is discussed and conclusions are drawn.

Towards nonadaptive and adaptive control of manipulation robots

Control synthesis for robotic systems with a variable payload is considered. First, we synthesize a robust, nonadaptive decentralized control using an approximative system model. Then, we analyze the stability of an exact system model. We thus check whether the robotic manipulator is stabilized for all allowable payload variations. If the simple decentralized control cannot accommodate all expected payload variations we introduce additional load, nonadaptive, feedback loop. This global control requires force transducers to be implemented in manipulator joints. If such nonadaptive control cannot stabilize robotic manipulator trajectories we suggest another adaptive control scheme. This control scheme includes an algorithm for on-line identification of variable payload and adaptation of local gains.

Pavement Strength Rating Methods as Viewed by Airframes Manufacturers

The effects of allowable aircraft payload of variations in tire pressure, axle spacing, and wheel spacing were explored using four important pavement design/rating methods. The methods used were the California Bearing Ratio (CBR) (SEFL165A variation) method (flexible pavement), the Load Classification Number (LCN) method (flexible and rigid pavement) and the Portland Cement Association method (rigid pavement). The effects on payload were determined for both dual and dual tandem type loading gear on pavements of an assumed strength. This analysis was followed by a study of the payload effects of variations on pavement parameters such as subgrade strength or pavement thickness in allowable aircraft payload given a particular aircraft configuration. Based upon the foregoing analysis five airframe manufacturer's objectives for new pavement design methods were stated.

Radiation - Tolerant Logarithmic Amplifier

In any conceptual design of a flight vehicle utilizing nuclear-type propulsion the amount of necessary shielding will detract from the allowable payload. The ability of electronic instruments to tolerate radiation and temperature extremes will then be of prime importance in these designs. This report describes the development and performance of a radiation and vibration tolerant instrument for use in the neutron flux control of a nuclear ramjet engine.