Lifting Mechanism Research Articles

Selection of Lifting Mechanism for Small-Scale Construction Project: A Comparative Method Based on Building Volume and an Automated Schedule

The selection of construction machinery for a project is a very important part of the construction process. Rigorous preparation for construction is very often neglected in practice even though three fifths of the construction companies in the Czech Republic operate at prices that lie below the safe pricing threshold. For small-scale buildings this ratio is even more pronounced. This fact can be understood as meaning that the price of construction is undervalued in such a way that it also has a negative impact on construction safety. On the other hand, the selection of a lifting mechanism usually relies on the individual decisionmaking capabilities of the construction manager, and the decision is mostly based on the options that are locally available. In such cases, the result is often that the total cost is disproportionately high and/or the lifting mechanism is oversized. The proper selection of the main lifting mechanism for a project depends on many factors and criteria, such as crane position, load characteristics, economic criteria and the flexibility of the schedule. Effective lifting mechanism selection fundamentally depends on the definition of the economic and technological criteria for each individual structure at the beginning of the project. This paper presents an approach developed by the authors to assess the suitability of a lifting mechanism for small-scale construction work based on an automated schedule in combination with the volume of the structure. A case study comparing two types of small self-erecting crane and a mobile crane is presented in order to prove the usefulness of this method. The results include a graph from which the suitability or unsuitability of each individual mechanism can be found. A cost curve with a transition point depicted for a range of six small-scale structures with different building volumes is shown for each mechanism. A clear transition point was found at a building volume of 6030 m3.

Method of calculation specific electrical conductivity of soil environment by working electrodes of information and technical system in local operational monitoring of agro-biological state of agricultural lands

Purpose. Develop a methodology for calculating the specific electrical conductivity of the soil environment with working electrodes to ensure the required quality of implementation of the main technological processes in plant cultivation thanks to integrated information and technical systems for operational monitoring of the agro-biological state of agricultural lands. Methods. Theoretical scientific method with the use of the laws of theoretical mechanics and scientific laws of electro-dynamic measurement for the construction of a method for calculating the specific conductivity of the soil environment by working electrodes of the information and technical system local operational monitoring the agro-biological state of agricultural lands. Results. The generalized formula for calculating the specific electrical conductivity of the soil environment by working electrodes information and technical system of local operational monitoring of agro-biological state of agricultural lands was obtained. Conclusions. The proposed method for calculating the specific electrical conductivity of the agro-biological ground environment by the stationary contact method of the working electrodes of the information and technical system local operational monitoring will allow obtaining reliable data on the state of the soil environment by reducing the error in determining the value of the electrical conductive properties soil, providing individual stabilization of the working electrodes and the mechanism of lifting / lowering the workers electrodes, copying roughness inequalities on the environment, reduction the intensity destruction of the soil structure, self-cleaning working contact electrode and ensuring the stability of the electrical contact electrode with the soil due to the improvement of the design of the device with the use of the proposed technical solutions. The result of using the device for determining the electrically conductive properties soil environment construction of Alexander Brovaryts is an increase in profits of 20–30% by optimizing the seeding rate of the process material, taking into account the agro-biological state of agricultural lands. Keywords: information and technical system, local operational monitoring, soil, samples, variability, size, research.

Composition and Application of Aircraft Towing Tractor Automatic Control System

The airports construction level is improved and the construction scale is constantly expanded with the rapid development of society, economy and science and technology, which brings a good development prospect for aircraft towing tractors. On the basis of summarizing the current research and application of aircraft towing tractors, the traction characteristics of towbar and towbarless aircraft tractors were analyzed, and the mechanical, electric, hydrodynamic and hydraulic transmission automatic control system were compared. The composition, working principle and application of hydraulic steering control system, hydraulic braking control system, hydraulic clamping and lifting mechanism and hydraulic hybrid power system of aircraft towing tractors were emphatically discussed. The results show that the configuration of towbarless traction is flexible and the traction capability is strong. Hydraulically controlled aircraft towing tractor has good traction, braking and control characteristics. Electronic hydraulic braking system is precisely controllable, and the hydraulic hybrid technology is beneficial to reduce the energy consumption of aircraft towing tractors. The demand for aircraft towing tractors is increasing with the expansion of the airport distribution and construction, on the basis of constantly improving the existing aircraft towing tractor and according to the needs of airport operation, it is necessary to adopt innovative technology to develop energy-saving, environment-friendly and intelligent aircraft towing tractors, so as to adapt the development needs of aviation industry.

Design and Field Test of a New Compact Self-Propelled Cabbage Harvester

Abstract. As a labor-intensive operation, manual harvesting greatly affects cost and therefore profitability in the cabbage industry. A new compact self-propelled cabbage harvester for small, separate fields was designed and field tested. This harvester included a crawler chassis, a picking mechanism, a lifting mechanism, a cutting device, and a leaf separator. Results of preliminary field tests showed that the harvester had good flexibility and maneuverability. Results of field performance tests showed that the harvester could pick cabbages with diameters of 15 to 25 cm, providing a harvesting capacity of 0.21 hm2 h-1 and a harvest loss of 10.2%. Compared with experiments conducted in traditional fields, harvest quality showed an improvement in fields with an experimental cultivation method. The harvest loss was reduced by 5.0%, while the picking rate and accurate cutting rate were improved by 3.0% and 5.4%, respectively. Keywords: Cabbage, Compact, Field test, Mechanical harvester, Self-propelled.

Something about a Railbound Forging Manipulator

Heavy payload forging manipulators are mainly characterized by large load output and large capacitive load input. The relationships between outputs and inputs have greatly influenced the control and reliability. Forging manipulators have become more prevalent in the industry today. They are used to manipulate objects to be forged. The most common forging manipulators are moving on a railway to have greater precision and stability. They have been called the rail-bound forging manipulators. In this paper, one presents the general aspects of a rail-bound forging manipulator, like geometry, structure, general kinematics and forces of the main mechanism from such manipulator. The kinematic scheme shows a typical forging manipulator, with the basic motions in operation process: Walking, the motion of the tong and buffering. The lifting mechanism consists of several parts including linkages, hydraulic drives and motion pairs. An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed. Self-forging systems have the ability to achieve an open, fast, direct forging of products that are often heavy and heavy but also bulky. Open forging productivity is generally very high, it is determined not only by the capacity of forging press but obviously dynamic handling by forging manipulator. The most prominent and qualitative forging machines are the DANGO and DIENENTHAL series, equipped with high dynamic devices and specially designed to operate on heavy forging presses. They ensure the reliability and repeatability of all forging cycles. Even a modernization of existing forging machines with D&D machines will improve the capacity and quality of these facilities. D&D handlers allow to forge nearly clean shapes and guarantee superior surface qualities, thus saving energy, improving production and saving costs during the machining of parts. Savings due to shorter process times and reduction of reheating cycles result in shorter recovery time.

Analysis of the supporting head fracture of a lifting mechanism

This paper introduces the working principle of a lifting mechanism and analyzes the end factors of the fault using the fault tree analysis method [1]. This paper also conducts strength analysis and physical and chemical analysis of the fractured supporting head, and determines that the cracks generated on the component surface due to the defect is the main cause of the supporting head fracture. Based on this, this paper proposes relevant solutions to improve the safety of the lifting mechanism.

Система управления взаимосвязанными электроприводами с электромеханическим распором и распределением нагрузки

The article presents the results from the development of a double-motor electromechanical system, in which the automatic control of interconnected electric drives ensures the formation of electromechanical torsion to maintain the closed state of backlash in the kinematic transmission within the specified load torque variation range. When the load torque escapes from the preset range, it is automatically distributed equally among the electric drives. The aims of this technical solution are to form a torsion when it is needed in accordance with the peculiarities of the load acting on the mechanism, and to prevent the installed capacity of electric drives from being exceeded in comparison with the power required for moving the mechanism. The application of the development results for controlling the motion of the antenna installation lifting axis is illustrated. The peculiarity of this system is that the load torque of this mechanism is active, sign- variable and depends on the lifting angle. When crossing the vertical position, it changes direction, which facilitates the opening of backlash in the kinematic transmission and the occurrence of self-oscillations. At lifting angles close to the horizontal position, the load torque has its maximum value, and the backlash is closed under its action. In addition, when the mechanism is near the vertical position, the wind load facilitates opening of the backlash. The system for controlling the electromechanical systems coordinates includes torque control loops, which are individual for each of the electric drives, and a loop that is common for control of their position. Recommendations for synthesizing these loops are given. The specified torsion torque is calculated by a nonlinear element with a trapezoidal I/O characteristic depending on the mismatch between the specified and actual angular position of the driving mechanism axis processed by the position controller, which makes it possible to indirectly estimate the load torque value. The control system software and hardware have been developed. In developing the microprocessor control system software, model-oriented development tools were used. A prototype replicating the antenna installation lifting mechanism design has been made. The proposed control system made it possible to reduce the influence of backlash at lifting angles close to the vertical position and to distribute the load torque between the electric drives at lifting angles close to the horizontal position, when torsion is not required, as well as when exposed to wind load. Experimental oscillograms of electromechanical system coordinates are presented, confirming the declared results.

Development of crawler robot with main body lifting mechanism

Development of crawler robot with main body lifting mechanism

Aerodynamic Analysis and Simulation of Flapping Wing Aerial Vehicles on Hovering

In order to design and verify control algorithms for flapping wing aerial vehicles(FWAVs), calculation models of the translational force, rotational force and virtual mass force were established with the basis on the modified quasi-steady aerodynamic theory and high lift mechanisms of insect flight. The simulation results show that the rotational force and virtual mass force can be ignored in the hovering FWAVs with simple harmonic motions in a cycle. The effects of the wing deformation on aerodynamic forces were investigated by regarding the maximum rotational angle of wingtip as a reference variable. The simulation results also show that the average lift coefficient increases and drag coefficient decreases with the increase of the maximum rotational angle of wingtip in the range of 0-90°.

The effects of protective footwear on spine control and lifting mechanics

Manual materials handling is often performed in hazardous environments where protective footwear must be worn; however, workers can wear different types of footwear depending on the hazards present. Therefore, the goal of this study was to investigate how three-dimensional lifting mechanics and trunk local dynamic stability are affected by different types of protective footwear (i.e. steel-toed shoes (unlaced boot), steel-toed boots (work boot), and steel-toed boots with a metatarsal guard (MET)). Twelve males and twelve females performed a repetitive lifting task at 10% of their maximum lifting effort, under three randomized footwear conditions. Footwear type influenced ankle range of motion (ROM). The work boot condition reduced ankle sagittal ROM (p = 0.007) and the MET condition reduced ankle ROM in the sagittal (p = 0.004), frontal (p = 0.001) and transverse (p = 0.003) planes. Despite these differences at the ankle, no other changes in participant lifting mechanics were observed.

Combined motion control of hydraulic boom based on dynamic surface adaptive fuzzy sliding mode

The lifting mechanism on the transfer vehicle is a common electromechanical–hydraulic system. In order to overcome the non-linear and interference that exist in the hydraulic boom combined motion process, a dynamic surface adaptive fuzzy sliding mode control method is proposed. The Lyapunov function and virtual control base on inversion of the sliding mode control are designed, the dynamic surface control is used to calculate the derivative of the virtual control, and the adaptive control is applied to estimate the parameter. Furthermore, the fuzzy control is applied to fuzzification the switching item of the sliding surface. Verified by simulation, the designed sliding mode controller has high control accuracy and strong robustness and eliminates system chatter.

Challenge and Advantage of Materials in Design and Fabrication of Composite UAV

Unmanned Aerial Vehicles (UAVs) is constructed with composite materials, including its aerodynamic surfaces wings, horizontal stabilizer, and rudder. Three main constituents of our model is Kevlar 49, carbon fibre, glass fibre. KALPANA-1 is a pusher type, tail dragger, fixed wing radio controlled medium range remotely operated composite aircraft. This is designed for Aerial surveillance & reconnaissance. It is a kind of drone which has capability of carrying 2kg of operational payload as surveillance camera and its gimbal mount unit. It can be equipped with on-board sensors for weather monitoring as civilian use of UAV. It has a carbon frame body which makes it hassle to work in all-weather environment, protecting its electronics and payload from external entities. KEVLAR-49 is reinforced at the bottom part of the fuselage to overcome hard landing & impacts. The main disadvantage of using carbon fibre is that it partially shelled the RC signals so we fixed our receiver outside of the fuselage. For camera mounting purpose a duct made in front side of fuselage. It can use as other diplomatic mission as mounting camera and robotic arm for weight lifting mechanism. Some further upgrading two semi ducts at two side of the front face of the fuselage for steerable camera mounting. Aircraft using single electrical propulsive system and large wings which helps it for a long range, good endurance and smooth steady flight. Composite materials don’t break easily, but that makes it hard to analyses if the interior structure has been damaged at all. In contrast, aluminum bends and dents easily, making it easy to detect structural damage; the same damage is much harder to detect with composite structures. Repairs can also be more difficult when a composite surface is damaged. Finally, composite materials can be expensive, but the high initial costs are typically offset by long-term cost savings and life cycle more compare to cost of material.

RELATIONSHIPS BETWEEN ARM SPAN AND THE MECHANICS OF THE ONE-REPETITION MAXIMUM TRADITIONAL AND CLOSE-GRIP BENCH PRESS

The traditional bench press (TBP), performed with a grip width that maximizes strength, is a popular exercise for developing the upper-body. The close-grip bench press (CGBP) is a variation of the TBP often used to emphasize the triceps brachii over prime movers such as the pectoralis major. An individual’s arm span (AS; distance between the middle fingers of each hand while the arms are outstretched) could affect the mechanics of each exercise, which may be exacerbated by the change in grip. This study investigated relationships between AS and TBP and CGBP mechanics in resistance-trained men. Twenty-one participants completed a one-repetition maximum (1RM) TBP and CGBP. The TBP was performed with the preferred grip (measured relative to biacromial distance [BAD]), and the CGBP with a grip width of 95% BAD. A linear position transducer measured: lift distance; peak and mean power, velocity, and force; the distance and time when peak power occurred; and work. Pearson’s correlations (r; p < 0.05) computed relationships between AS and TBP and CGBP mechanics. There were significant positive relationships between AS and TBP lift distance and work (r = 0.46 and 0.51, respectively). For the CGBP, there was a significant positive relationship between AS and work (r = 0.48). There were no other significant correlations between AS and lift mechanics. Resistance-trained men with a longer AS may move the bar further and perform more work in the 1RM TBP and CGBP. This could influence how coaches measure training volume, and intensity for individuals with different AS.

Robustness analysis of fractional order PID for an electrical aerial platform

This work was performed to objectively measure and assess the robustness and tracking performance of fractional order of proportional, integral and derivative (FOPID) controller as compared to the conventional PID control. In satellite research and development, the satellite undergoes numerous tests such as thermal, acoustic and vibration tests in the cleanroom environment. However, due to space limitation in the cleanroom and the sensitive components of the satellite, it requires vibration-free, smooth and precise motion when handling the satellite. In addition, measurement interference might occur due to cable routing during procedures or tasks performed by an operator. Unlike the previous work, the robustness analysis of FOPID controller was not systematically conducted. In this paper, the analysis took into account the actuator dynamics, and various tests were considered to measure the robustness of FOPID controller. The designed FOPID controller was implemented on the scissor-type lifting mechanism of motorized adjustable vertical platform (MAVeP) model, and its performance was compared with the traditional PID controller. A comprehensive verification using MATLAB and Solidworks was carried out to generate the model and conduct the analysis. Both controllers were initially tuned using Nichol-Ziegler technique, and the additional FOPID controller parameters was tuned using the Astrom-Hagglund method. From the simulation work, it was found that the FOPID controller’s tracking error was reduced between 10 % - 50 % for the disturbance rejection tests and reference to disturbance ratio (RDR) spectrum was higher as compared to PID. The analysis in this paper was predicted to be the main driver to implement FOPID controller in the complex system in the industry, especially for sensitive material handling and transportation such as satellite.

Novel Design of Master Manipulator for Robotic Catheter System

This paper presents a new master manipulator applied to robotic systems for arrhythmia ablation. The manipulator is designed to implement the concept of two different master-slave teleoperation controls in the clinical application. One is the conventional control between the master and catheter-handle in the slave site and the other is catheter tip manipulation corresponding the master motion. For the purpose, the master has six degrees of freedom (DOF) and consists of three main components: a spherical mechanism for rotational motion of 2-DOF, 3-RRR planar parallel mechanism with 3-DOF, and counter-weight lifting mechanism for the vertical movement. Two mechanisms except the lifting mechanism are parallel chains and structurally more complicated. Therefore, their forward kinematics are analyzed, and workspaces are simulated. To evaluate the applicability for robotic catheter systems, the manipulator prototype was tested for its smoothness, workspace, and teleoperation performance. The subjects in the smoothness test reported no considerable friction and jerk in free movement in the three-dimensional space as shown in the recorded curves. The workspace test shows the actual workspace is similar to the simulated one except some structural constraints in the 3-RRR mechanism. For the last test, a robotic catheter teleoperation system with a slave robot and the software structure for the robotic catheter control system with electrical connection of each component were built. The result performed by five different users shows the motion of the slave robot well tracks that of the master device with small average errors and time delay that are acceptable in robotic catheter teleoperation systems.

Cargo stop-gear of the lifting mechanisms in the form of a closed circuit hydrosystem

Stoppers are used to hold loads at a height and prevent their uncontrolled reversal movement in manual and mechanical drives of lifting mechanisms. Recent researches have shown that scientists, designers and constructors continue to look for ways to improve the design and operation of cargo brakes and stoppers, therefore the development of the latter remains relevant scientific and technical task. The article describes the structure of new cargo stop-gear, which contains a gear pump, short pipelines, regulating throttle, reverse valves and a liquid container. All the parts are mounted on the frame of the pump. The work of the cargo stop-gear operated from the lifting mechanism has been considered. The gear pump is driven in the direction of cargo lifting,and pumps the liquid through an open circuit of the hydrosystem. Upon completion of lifting, the cargo stops and creates a reverse torque, the direction of the pump rotation changes and stops, because the reverse circuit of the hydrosystem is closed by the regulating throttle. To lower the cargo a regulating throttle is used- the return circle of the closed circuit hydrosystem opens, the gear pump is driven and it pumps the liquid in the reverse circuit of the hydrosystem. When we want to stop the movement of the cargo – the regulating throttle overlaps the reverse circuit of the closed circuit hydrosystem. The recommendations on the selection and calculation of components of the cargo stop-gear of the lifting mechanism have been given. The proposed cargo stop-gear in the form of a closed circuit hydrosystem is advisable to use in load-lifting and other equipment, as the durability of parts increases and energy costs reduce during its operation

Energy-saving Design and Simulation Analysis of the Baggage Diversion Lifting Mechanism

Energy-saving Design and Simulation Analysis of the Baggage Diversion Lifting Mechanism

Vibration Analysis and Control of Nuclear Power Crane with MRFD

The nuclear power crane is required to have high security and stability, as its lifting mechanism and span structure are needed to perform predominantly in serious working conditions. A new vibration analysis and control method on the nuclear power crane is proposed to improve its stability, which is based on magneto rheological fluid damper (MRFD) and switch algorithm control strategy. The simulation is completed through dynamic model and control model. The experiment is accomplished in a serving crane. Both numerical simulated and experimental results show that the vibration of nuclear power crane is suppressed significantly with MRFD. It is proved that MRFD should be taken into consideration in the vibration control of nuclear power crane.

Reciprocal theorem for the prediction of the normal force induced on a particle translating parallel to an elastic membrane

When an elastic object is dragged through a viscous fluid tangent to a rigid boundary, it experiences a lift force perpendicular to its direction of motion. An analogous lift mechanism occurs when a rigid symmetric object translates parallel to an elastic interface or a soft substrate. The induced lift force is attributed to an elastohydrodynamic coupling that arises from the breaking of the flow reversal symmetry induced by the elastic deformation of the translating object or the interface. Here we derive explicit analytical expressions for the quasi-steady state lift force exerted on a rigid spherical particle translating parallel to a finite-sized membrane exhibiting a resistance toward both shear and bending. Our analytical approach proceeds through the application of the Lorentz reciprocal theorem so as to obtain the solution of the flow problem using a perturbation technique for small deformations of the membrane. We find that the shear-related contribution to the normal force leads to an attractive interaction between the particle and the membrane. This emerging attractive force decreases quadratically with the system size to eventually vanish in the limit of an infinitely-extended membrane. In contrast, membrane bending leads to a repulsive interaction whose effect becomes more pronounced upon increasing the system size, where the lift force is found to diverge logarithmically for an infinitely-large membrane. The unphysical divergence of the bending-induced lift force can be rendered finite by regularizing the solution with a cut-off length beyond which the bending forces become subdominant to an external body force.

Development of the gearless electric drive for the elevator lifting mechanism

A technical analysis of the requirements for drive motors and rope driving pulleys of gearless elevator winches was performed. The possibility of application of the developed slow-moving electric motor of the bi-induction type with the unwound rotor was considered. A similar motor was produced with the rotor of the face or cylindrical type and the stator, which do not have a common yoke. The face type rotor comprises a few ferromagnetic poles fixed on a non-magnetic disk. The main design parameters of bi-induction motors for the series of speeds of the elevator car motion were generated. Recommendations on selection and compliance of the rates of elevator winches with the diameters of rope driving pullies were given. The synthesis of the system of control of the elevator electric drive was performed. It is proposed to use the microprocessor system of subordinate control of the use of the relay current controller, PI-controller of rate and P-controller of position. The results of the research revealed that there is a possibility of the exact reproduction of the assigned trajectory of the car motion and the exact stop, made on a certain floor without additional operations of approaching the assigned point. The motion is performed according to the calculated trajectory with restriction of the assigned speed at the level of the rated one, acceleration – up to 1 m/s2 and the jerk – up to 3 m/s2. These parameters fully meet the conditions of comfortable passenger transportation. The difference between the experimental data and the results of modelling does not exceed 7 % in the static and 15 % in dynamic modes. The main advantages of the proposed gearless elevator electric drive were specified. In particular, it was determined that the proposed electric drive due to the design features of the quietly operating motor has much lower weight, dimensions and inertia than the traditional one in the basic option at the other similar parameters.