scholarly journals Investigation of a Digital Hydraulic Valve Operated by Servo Motors

2021 ◽  
Vol 11 (6) ◽  
pp. 7957-7963
Author(s):  
A. F. Ozalp ◽  
R. Polat ◽  
C. Cetinkaya ◽  
M. H. Cetin
Keyword(s):  
Pulse Number ◽  
Control Technique ◽  
Hydraulic Systems ◽  
Servo Motor ◽  
Pulse Code Modulation ◽  
Valve Body ◽  
Flow Rates ◽  
Valve Assembly ◽  
New Type ◽  
Hydraulic Valve

This paper describes a new type of digital hydraulic valve run by two servo motors. Digital hydraulics is a cutting-edge technology, which saves more exhausted energy than conventional hydraulic valves. It includes conventional valves, but its working principle is different. Similar or different size valves constitute a digital hydraulic valve assembly. When the assigned valves are opened, a certain amount of flow is obtained from the output of the valve assembly. To control a digital hydraulic valve, Pulse Number Modulation (PNM) Control technique is used for equal valve flow rates, while Pulse Code Modulation (PCM) is used for different valve flow rates. Valves are exerted by independently launched electric coils. Previous studies used controller board and external power booster circuits for coils. In this study, a new type of digital hydraulic valve is designed, manufactured, and tested with the PNM method. The studied valve body has two different valve groups. Every group includes 16 equal valves and 1 camshaft rotated by 1 servo motor. The servo motors are controlled by a PLC. The calculated performance index is found to be 5.1ms which is similar to the results of previous studies. The experimental results showed that the cam and servo motor controlled digital hydraulics is applicable to variable speed control hydraulic systems.

Research on a New Type of Lithium Battery String Equalization and Management System

2011 ◽  
Vol 383-390 ◽  
pp. 1470-1476
Author(s):  
Hao Wang ◽  
Ding Guo Shao ◽  
Lu Xu
Keyword(s):  
Lithium Batteries ◽  
Management System ◽  
Lithium Battery ◽  
Large Scale ◽  
Control Method ◽  
Balance Control ◽  
Industrial Applications ◽  
Control Technique ◽  
New Type ◽  
Management Functions

Lithium battery has been employed widely in many industrial applications. Parameter mismatches between lithium batteries along a series string is the critical limits of the large-scale applications in high power situation. Maintaining equalization between batteries is the key technique in lithium batteries application. This paper summarizes normal equalization techniques and proposed a new type of lithium Battery Equalization and Management System (BEMS) employing the isolated DC-DC converter structure. The system is integrated both equalization functions and management functions by using distributed 3-level controlled structure and digital control technique. With this control method the flexibility of the balance control strategy and the compatibility for different battery strings are both improved dramatically. The experimental results show optimizing equalization, efficiency and the battery string life span has been extended.

Soft Switching Approach to Reducing Transition Losses in an On/Off Hydraulic Valve

2009 ◽  
Author(s):  
Michael B. Rannow ◽  
Perry Y. Li
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Fluid Flows ◽  
Soft Switching ◽  
Total System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Flow Through ◽  
Hydraulic Valve

A method for significantly reducing the losses associated with an on/off controlled hydraulic system is proposed. There has been a growing interest in the use of on/off valves to control hydraulic systems as a means of improving system efficiency. While on/off valves are efficient when they are fully open or fully closed, a significant amount of energy can be lost in throttling as the valve transitions between the two states. A soft switching approach is proposed as a method of eliminating the majority of these transition losses. The operating principle of soft switching is that fluid can temporarily flow through a check valve or into a small chamber while valve orifices are partially closed. The fluid can then flow out of the chamber once the valve has fully transitioned. Thus, fluid flows through the valve only when it is in its most efficient fully open state. A model of the system is derived and simulated, with results indicating that the soft switching approach can reduce transition and compressibility losses by 79%, and total system losses by 66%. Design equations are also derived. The soft switching approach has the potential to improve the efficiency of on/off controlled systems and is particularly important as switching frequencies are increased. The soft switching approach will also facilitate the use of slower on/off valves for effective on/off control; in simulation, a valve with soft switching matched the efficiency an on/off valve that was 5 times faster.

Design, Development, and Characterization of a Flow Control Device for Dynamic Cooling of Liquid-Cooled Servers

2021 ◽  
Author(s):  
Pardeep Shahi ◽  
Apurv Deshmukh ◽  
Hardik Hurnekar ◽  
Satyam Saini ◽  
Pratik V Bansode ◽  
...  
Keyword(s):  
Thermal Management ◽  
Flow Rate ◽  
Control Device ◽  
Servo Motor ◽  
Pumping Power ◽  
Liquid Cooling ◽  
Flow Rates ◽  
Flow Control Device ◽  
Dynamic Cooling ◽  
Valve Position

Abstract Transistor density trends till recently have been following Moore's law, doubling every generation resulting in increased power density. The computational performance gains with the breakdown of Moore's law were achieved by using multi-core processors, leading to non-uniform power distribution and localized high temperatures making thermal management even more challenging. Cold plate-based liquid cooling has proven to be one of the most efficient technologies in overcoming these thermal management issues. Traditional liquid-cooled data center deployments provide a constant flow rate to servers irrespective of the workload, leading to excessive consumption of coolant pumping power. Therefore, a further enhancement in the efficiency of implementation of liquid cooling in data centers is possible. The present investigation proposes the implementation of dynamic cooling using an active flow control device to regulate the coolant flow rates at the server level. This device can aid in pumping power savings by controlling the flow rates based on server utilization. The FCD design contains a V-cut ball valve connected to a micro servo motor used for varying the device valve angle. The valve position was varied to change the flow rate through the valve by servo motor actuation based on pre-decided rotational angles. The device operation was characterized by quantifying the flow rates and pressure drop across the device by changing the valve position using both CFD and experiments. The proposed FCD was able to vary the flow rate between 0.09 lpm to 4 lpm at different valve positions.

A Software Design of Data Acquisition System Based on Optimal Control AMT

2013 ◽  
Vol 765-767 ◽  
pp. 1969-1973
Author(s):  
Yu Cheng ◽  
Hong Wei Zhao ◽  
Song Wang ◽  
Wei Lv ◽  
Tao Sun
Keyword(s):  
Data Collection ◽  
Software Design ◽  
Processing System ◽  
Data Acquisition System ◽  
Control Technique ◽  
Mechanical Transmission ◽  
Hydraulic Control ◽  
Collection System ◽  
Total Structure ◽  
Hydraulic Valve

As the developing of the automatic manipulate control technique of automobile, the research and development of Automated Transmission have abstracted more and more attention. In numerous Automated Transmission productions, AMT (Automated Mechanical Transmission) plays an absolutely important role. This system is a AMT data collection system based on electro-hydraulic control. According to the design of the system software program, we can collect and analyze the data of driving, and then mark the electro-hydraulic valve. This paper designs and realizes the total structure of data collection and processing system, analyses and designs the function of all modules elaborately. It is the summary of the front period work of the whole AMT system, and is the foundation of the work of function realization and running and debugging of AMT system.

The Double Role Piston Pump Based on the Symmetrical Gears and Crank-Link-Slider Mechanism Driven by Servo Motor

2011 ◽  
Vol 121-126 ◽  
pp. 2308-2312
Author(s):  
Ming Di Wang ◽  
Qiang Song ◽  
Kang Min Zhong
Keyword(s):  
High Speed ◽  
Noise Pollution ◽  
Hydraulic Cylinder ◽  
Piston Pump ◽  
Servo Motor ◽  
Straight Line ◽  
Wide Range ◽  
Cylinder Piston ◽  
High Speed Rotation ◽  
New Type

The double role piston pump based on the symmetrical gear and crank-link-slider mechanism driven by servo motor is innovated, its working principle and technical characteristics are introduced. In this new type of piston pump, the hydraulic cylinder piston is drived, and the velocity can be adjusted, but the flow pulse of a single pump is undoubtedly great. So two piston pumps are adopted, whose velocity are controled by NC, then the variable stepless timing in wide range can be achieved. If the velocity in this two pumps |v1|+|v2|=C (C is a constant), the flow curve of two pumps will be coupled into a straight line, in order to achieve constant flow output without the need of complex and inefficient throttle controlling loops, and there has not any power machines and mechanical parts in high-speed rotation ,and the noise pollution is very low. According to the varied circumstance, the high and low pressure conversion can be achieved when the angle velocity in this piston pump is controlled by the instructions. It is also very easy to achieve the dynamic and intelligent control.

Fault Tolerance of a Reconfigurable Tilt-Rotor Quadcopter Using Sliding Mode Control

2018 ◽  
Author(s):  
Siddharth Sridhar ◽  
Rumit Kumar ◽  
Kelly Cohen ◽  
Manish Kumar
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Control Technique ◽  
State Variables ◽  
Servo Motor ◽  
Tracking Errors ◽  
Tilt Rotor ◽  
Sliding Surfaces ◽  
Mode Control ◽  
Non Linear

Tilt-rotor quadcopters are a novel class of quadcopters with a servo motor attached on each arm that assist the quadcopter’s rotors to tilt to a desired angle thereby enabling thrust vectoring. Using these additional tilt angles, this type of a quadcopter can be used to achieve desired trajectories with faster maneuvering and can handle external disturbances better than a conventional quadcopter. In this paper, a non-linear controller has been designed using sliding mode technique for the pitch, roll, yaw motions and the servo motor tilt angles of the quadcopter. The dynamic model of the tilt-rotor quadcopter is presented, based on which sliding surfaces were designed to minimize the tracking errors. Using the control inputs derived from these sliding surfaces, the state variables converge to their desired values in finite-time. Further, the non-linear sliding surface coefficients are obtained by stability analysis. The robustness of this proposed sliding mode control technique is shown when a faulty motor scenario is introduced. The quadcopter transforms into a T-copter design upon motor failure thereby abetting the UAV to cope up with the instabilities experienced in yaw, pitch and roll axes and still completing the flight mission. The dynamics of the T-copter design and the derivation of the switching surface coefficients for this reconfigurable system are also presented.

An Experimental Study of a “Once-Through” Thermosiphon System

1988 ◽  
Vol 110 (2) ◽  
pp. 90-97 ◽  
Author(s):  
R. Celentano ◽  
R. Kirchner
Keyword(s):  
Experimental Study ◽  
Mass Flow ◽  
Natural Circulation ◽  
Time Dependent ◽  
Circulation System ◽  
Outlet Temperature ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
New Type ◽  
Mass Flows

An experimental study was conducted on the operation of a “once-through” thermosiphon system. This new type of natural circulation system, unlike the standard thermosiphon system, heats the collector fluid in one pass without any recirculation. An electrically heated manifold was used to simulate the useful solar gain. Power was varied with time in 22 half-hour increments to simulate the actual daily useful solar gain. The time-dependent responses of the system in terms of temperatures and mass flow rates were recorded and plotted. The response time for mass flow and temperature to approach steady state varied directly with the size of the power step. Two experiments were conducted; one which tracked mass flows and outlet temperatures for variable useful solar gains, and a second which tracked mass flows at constant outlet temperature for variable useful solar gains.

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