This study investigates concept of introduction of a hydraulic motor in the nacelle to convert rotor shaft work into hydraulic power that is transmitted to the electric generator at ground/sea level. ...This combination of hydraulic and electric power generation can help simplify or even eliminate the gearbox, and significantly reduce the head weight mass that the tower needs to support. Also, this hybrid concept allows energy storage in the tower which can reduce electric generator size. The analytical technique for tower mass savings employed herein was validated and used to show that 33%–50% of the tower mass may be saved through decreased tower thickness. In addition, the hydraulic-electric generator concept is compatible with employing isothermal CAES in the tower. Analysis based on cross-over pressure for the design limit indicates that this energy storage concept provides more than 24 h of energy storage if one considers S-glass towers of 10 MW or more. To accompany the above engineering analysis, a CAPEX cost model was developed based on recent production wind turbines and system designs. The hydraulic-electric hybrid system with CAES was estimated to yield a total CAPEX savings of 17% due to a substantial decrease in generator and electrical infrastructure costs.
•Investigated engineering aspects and feasibility of using hybrid generator concept.•Quantified cost savings associated with hybrid hydraulic-electric generator concept.•Developed novel concept of compressed air energy storage inside the turbine tower.•Hybrid design with novel tower storage allows capital expenditure savings of 17%.
The article discusses the task of modeling the working hydrodynamic processes occurring in hydraulic drives with frequency-throttle regulation of the mechanisms of movement of traction and ...load-bearing ropes, at all stages of the movement mechanism — the stage of acceleration of the transported cargo, the stage of steady (stationary) movement with constant speed and the stage of braking when approaching the final breakpoint. As a circuit that implements throttle control, possible hydraulic circuit designs for sequential installation of adjustable throttles relative to the hydraulic motor are considered — one-sided installation of one throttle and two-sided installation of two throttles with the same and different settings. To solve this technical problem, a mathematical model of the hydraulic drive and a computer program that implements it were developed. The model provides a computer simulation over time of the processes of change over time of such basic technical characteristics of the hydraulic drive as pressure and volumetric flow rates of the working fluid at characteristic points along the length of the hydraulic system, pressure drop across the hydraulic motor and instantaneous hydraulic drive power, as well as kinematic and power motion parameters of traction and load-bearing ropes (distance traveled, linear speed and acceleration, required power, overcome operating loads). In relation to a specific variant of the mobile rope complex, the calculations of the indicated hydrodynamic, kinematic and power parameters were carried out, as well as the analysis of the results obtained. The effect of various options for installing adjustable throttles and their settings on the calculation results is shown.
This paper presents an analysis of the effect of the area and heat transfer coefficient on the thermal mode of the hydraulic drive, construction road equipment, an example of calculation on a ...computer. The possibility of using the method in engineering calculations is considered. A graph of the heating intensity of the working fluid depending on the value of the heat transfer coefficient of the hydraulic drive and a graph of the heating intensity of the working fluid depending on the area of the fuel surfaces were compiled. The invention proposes the use of dual hydraulic tanks in self-propelled machines.
Introduction. The article describes the test bench specialized software, developed for technical inspection of domestic and foreign volumetric hydraulic drives in repair enterprises and service ...centers. The results of bench tests using a hydraulic bench and software are presented.
Materials and Methods For the application software development, G graphical programming language of the Laboratory Virtual Instrumentation Engineering Workbench (Lab- View) programming environment developed by the National Instruments Company has been used. The reliability of the results obtained has been confirmed by a series of bench tests of domestic and foreign volumetric hydraulic drives.
Results. There has been developed and implemented new test bench software for the technical inspection of hydraulic drives of different models from domestic and foreign manufacturers in repair plants and service centers. The software is used to capture, process and store data from the sensors during testing, to calculate and output measurement data, to conduct nonlaboratory analysis of the testing process in graphical, textual and video formats, to calibrate sensors, and to store the test results in the electronic library system. The specialized software runs under the Microsoft Windows 7 x86 (32-bit) operating system and is installed on a personal computer of the hydraulic bench data processing unit. The developed software is characterized by the ergonomics of the user interface, the ability to control all the parameters of diagnosing the tested volumetric hydraulic drives.
Discussion and Conclusion. Specialized software and the test bench permit high accurate monitoring of all technical condition parameters of the most common domestic and foreign volumetric hydraulic drives in accordance with the requirements of the manufacturers in the repair enterprises and service centers.
It is crucial for serial robots with redundant degrees-of-freedom to accomplish complex tasks with high pose precision of the end-effector. However, due to the cumulative errors in each joint ...actuator, it is always challenging to guarantee high pose precision of the end-effector. To address this issue, this study proposes a virtual-constraints-based end-effector pose compensator. The actual angles of specific joints are treated as known variables, which are called virtual constraints. The virtual constraints, combined with the expected pose of the end-effector, yield compensation angles for the other joints. The compensation angles are applied to the expected angles of other joints, eliminating the end-effector pose errors caused by the joints treated as virtual constraints. Finally, a typical planar 3-degree-of-freedom serial robot (the leg hydraulic drive system for legged robots) is utilized for experimental validation. The experimental results demonstrate that, with the application of the compensator, the maximum reduction in position error of the foot end exceeds 75%. The compensation strategy further improves the end-effector pose precision based on various high-precision position control methods for the joint actuators. In addition, this study introduces a novel idea and provides experimental evidence for compensating the end-effector pose error of redundant serial robots.
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The success of the shooting of a moving vehicle can be achieved by providing barrel stabilization. In the meantime, it is necessary barrel angle must be positioned is instantaneously calculated ...accurately. In this paper, the required barrel elevation angle was calculated via artificial neural networks and the shooting success to a fixed target from a moving tank was investigated. For this purpose, a mathematical model of a tank, which has four degrees of freedom, with a barrel mounted on it has been utilized. The barrel is moved using an inverted slider mechanism. The system is driven hydraulically by considering the movement of the piston–cylinder pair in the inverted slider mechanism. The conventional PID control method has been preferred for angular position control of the barrel. Simulations have been performed with the MATLAB package program. System responses have been obtained graphically and the results have been presented in tabular form. It is seen that the pressure, flow, etc. obtained from the results overlap with the physical system. It is observed that the elevation angle of 10 degrees is captured and shot very well when the vehicle is stationary. In the moving state of the vehicle, the 10-degree elevation angle capture as well. In the moving case, there are tiny deviations in the target hit but these values can be considered to be reasonable levels. The deviation amount for the target 4 kilometers away is 16.28 meters.
In view of the problems of the output power and operation, when the multi-function machine in hilly and mountainous areas driving in the field, the hydraulic control drive system of small ...multi-function agricultural hydraulic chassis is designed. The key components of the hydraulic drive system were selected and matched. The hydraulic system simulation model was established in AMESim simulation analysis software, and the dynamic analysis of the hydraulic system operation under different conditions is carried out. The simulation analysis results show that the hydraulic system has a large impact and vibration when it is started instantaneously, and the hydraulic system has smaller impact and vibration when it is started stably. It is consistent with the actual working state of the hydraulic chassis. Under the two starting controls, the maximum flow of the hydraulic pump is 50L/min, the motor torque is about 440N • m, and the motor stable pressure is 6Mpa, the motor speed is 96 r/min, which is within the bearing range of the hydraulic components. The simulation output parameters are basically consistent with the theoretical calculation results, and meeting the design requirements. The chassis performance test results show that the maximum crossing height of the chassis is 200mm, the crossing width is 300mm, the maximum deviation of high-speed straight driving is 2.57m, it can stably pass 20° slope, and the operation is stable and the steering is flexible. All performance parameters can better meet the requirements of chassis operation in hilly and mountainous areas.
Mobile ropeways, the equipment of which is located on the base chassis of wheeled or tracked vehicles of high carrying capacity, are a promising type of transport and overloading equipment. Specific ...design features, modes and conditions of their operation in comparison with traditional freight and passenger fixed-line cableways require the development of special design methods and design calculations for this type of machine. The article discusses the problem of modeling working hydrodynamic processes in hydraulic drives with frequency-throttle regulation of the mechanisms of movement of traction and carrying ropes, at all stages of the movement mechanism — the stage of acceleration of the transported cargo, the stage of steady-state (stationary) movement at a constant speed and the stage of braking when approaching the final breakpoint. To solve this technical problem, a mathematical model of the hydraulic drive and a computer program that implements it were developed. The model provides computer simulation of the time-varying processes of such basic hydraulic drive technical characteristics as pressures and volumetric flow rates of the working fluid at characteristic points along the length of the hydraulic system, pressure drop across the hydraulic motor and instantaneous hydraulic drive power, as well as kinematic and force parameters of the movement of traction and carrying ropes (distance traveled, linear speed and acceleration, required power, overcome operational loads). In relation to a specific version of the mobile rope complex, the calculations of the indicated hydrodynamic, kinematic and power parameters were carried out, as well as the analysis of the results obtained. The influence of the adjustable throttle setting on the calculation results is shown.
Throughout previous practice, estimating the life of aviation hydraulic drive assemblies has been utilizing a variant, which requires
conducting long-lasting studies of the drive assemblies until ...they move to the unfitness state. Such studies, which enable estimating life a posteriori, are costly and long-lasting. Hence the need to look for new strategies for estimating life. The article presents
a method of estimating the durability of a hydraulic drive assembly based on the control of its change in technical condition. Inspection of the technical condition enables timely detection of the condition before the emergency hydraulic assembly. The novelty of the
method is to use, to detect the condition before the emergency team, the principle of determining the pre-emptive control parameter
tolerance. Pre-emptive tolerances are a set of control parameter values between threshold levels and pre-emergency (allowable)
levels. The intensity of depletion of durability (intensity of aging, wear) is random. The paper presents a stochastic description of
the control parameter change and the resulting empirical relationships between the control parameter verification time probability
density (verification periodicity) and the control parameter value change probability density. The inter-relations between these two
functions were described. It also presents empirical relationships enabling the determination of the permissible value for the control
parameters and the periodicity of the control parameter checks after exceeding the limit value. An example of estimating the life of
a hydraulic piston pump on-board an aircraft operated in the Polish Air Forces was shown. The permissible values and the time
for the first control parameter verification after exceeding the limit value were determined for selected control parameters of the
hydraulic pump. The proposed method binds life (fitness time) with the physical wear mechanisms concerning the assemblies. It
can be applied in work aimed at determining the resource life of technical equipment. Furthermore, it enables utilizing technical
equipment according to a technical state strategy with monitoring the parameters.
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