scholarly journals Compound Velocity Synchronizing Control Strategy for Electro-Hydraulic Load Simulator and Its Engineering Application

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Songshan Han ◽  
Zongxia Jiao ◽  
Jianyong Yao ◽  
Yaoxing Shang
Keyword(s):  
Engineering Application ◽  
Operating Conditions ◽  
Accurate Information ◽  
Tracking Accuracy ◽  
External Disturbances ◽  
Acceleration Signal ◽  
Motion System ◽  
New Strategy ◽  
Hydraulic Load ◽  
Load Simulator

An electro-hydraulic load simulator (EHLS) is a typical case of torque systems with strong external disturbances from hydraulic motion systems. A new velocity synchronizing compensation strategy is proposed in this paper to eliminate motion disturbances, based on theoretical and experimental analysis of a structure invariance method and traditional velocity synchronizing compensation controller (TVSM). This strategy only uses the servo-valve's control signal of motion system and torque feedback of torque system, which could avoid the requirement on the velocity and acceleration signal in the structure invariance method, and effectively achieve a more accurate velocity synchronizing compensation in large loading conditions than a TVSM. In order to facilitate the implementation of this strategy in engineering cases, the selection rules for compensation parameters are proposed. It does not rely on any accurate information of structure parameters. This paper presents the comparison data of an EHLS with various typical operating conditions using three controllers, i.e., closed loop proportional integral derivative (PID) controller, TVSM, and the proposed improved velocity synchronizing controller. Experiments are conducted to confirm that the new strategy performs well against motion disturbances. It is more effective to improve the tracking accuracy and is a more appropriate choice for engineering applications.

Surplus Torque Elimination Control of Electro-Hydraulic Load Simulator Based on Actuator Velocity Input Feedforword Compensating Method

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Zhihui Li ◽  
Yaoxing Shang ◽  
Zongxia Jiao ◽  
Shuai Wu ◽  
Jianyong Yao
Keyword(s):  
Torque Control ◽  
Hardware In The Loop ◽  
New Strategy ◽  
Hydraulic Load ◽  
Actuator System ◽  
Load Simulator ◽  
Load Simulation ◽  
The Mathematical Model ◽  
Surplus Torque ◽  
Velocity Input

Electro-hydraulic load simulator (EHLS) is a typical closed-loop torque control system. It is used to simulate the load of aircraft actuator on ground hardware-in-the-loop simulation and experiments. In general, EHLS is fixed with actuator shaft together. Thus, the movement of actuator has interference torque named the surplus torque on the EHLS. The surplus torque is not only related to the velocity of the actuator movement, but also related to the frequency of actuator movement. Especially when the model of the actuator and EHLS is dissimilar, the surplus torque is obviously different on different frequencies. In order to eliminate the surplus torque for accurate load simulation, the actuator velocity input feedforword compensating method (AVIFC) is proposed in this paper. In this strategy, the actuator velocity synchronous signals are used for compensation of different frequency actuator movement to eliminate surplus torque on different frequencies. First, the mathematical model of EHLS and the actuator system is established. Based on the models, the AVIFC method is proposed. It reveals the reason that generates surplus torque on different frequencies of actuator. For verification, simulations and experiments are conducted to prove that the new strategy performs well against low, medium, and high frequency movement interference. The results show that this method can effectively suppress the surplus torque with different frequencies and improve precision of EHLS with actuator movement.

Research on Adaptive PID Control for Load Simulator with Varying Load

2014 ◽  
Vol 568-570 ◽  
pp. 1031-1035
Author(s):  
Ju Tian ◽  
Yao Chen
Keyword(s):  
Pid Control ◽  
Simple Structure ◽  
Control Method ◽  
Parameter Tuning ◽  
Hardware In The Loop ◽  
Tuning Method ◽  
Hydraulic Load ◽  
Variation Characteristics ◽  
Load Simulator ◽  
Adaptive Pid Control

The electro-hydraulic load simulator is an important equipment for aircraft hardware-in-the-loop simulation. An adaptive PID control method for compensating extraneous torque with simple structure and easy to implement is proposed according to the variation characteristics of load gradient in the load simulator. The control parameter tuning method is also given.

Study on Characteristics of the Linear Air-Conditioner Compressor at Varied Operating Conditions

2011 ◽  
Vol 201-203 ◽  
pp. 632-636 ◽  
Author(s):  
Jie Fei Xie ◽  
Xin Hua Li ◽  
Hong Zhang
Keyword(s):  
Engineering Application ◽  
Axial Direction ◽  
Operating Conditions ◽  
Air Conditioner ◽  
Design Development ◽  
Runge Kutta Method ◽  
Moving Body ◽  
Cylinder Piston ◽  
Compressor Performance ◽  
Intake Pressure

This paper mainly introduces a novel linear air conditioner compressor which is driven by the linear oscillatory motor with two divided moving body, of which the Cylinder-piston assembly presents symmetrical distribution along the axial direction. The compressor dynamics equations were built and solved numerically with the fourth order Runge-Kutta method. in the meantime, this paper emphatically analyzes the influence of those factors, such as the intake pressure, the exhaust pressure, the suction gas superheat, the cooling degree, on the compressor performance at varied operating conditions. These works shows that improving the suction gas pressure and reducing the exhuast pressure can help to increase the refrigeration capacity and energy efficiency ratio of the air conditioner compressor. Those analysis results provide theory foundation for design,development, and engineering application of this linear air-conditioner compressor.

CAD in the CIM Environment: Where Do We Go From Here?

1986 ◽  
Vol 39 (9) ◽  
pp. 1345-1349 ◽  
Author(s):  
Dell K. Allen ◽  
W. Van Twelves
Keyword(s):  
Computer Aided Design ◽  
Material Selection ◽  
Operating Conditions ◽  
Computer Integrated Manufacturing ◽  
Accurate Information ◽  
Functional Requirements ◽  
Essential Information ◽  
Design Systems ◽  
Aided Design ◽  
Product Definition

The importance of computer-aided design (CAD) has not been fully appreciated as it relates to computer integrated manufacturing (CIM). The CAD product definition model can provide essential information for many down-stream production, estimating, tooling, and quality assurance functions in the CIM environment. However, the product definition model may be inaccurate or incomplete, thus causing incomplete communication with possible scrap, re-work, and missed production deadlines. Other problems are related to the fact that many of our expert designers are retiring and taking their expertise with them. Merely being able to make 2D or 3D drawings on a CAD workstation does not make its operator a designer. A knowledge of production processes, tolerances, surface finish, and material selection is needed to supplement a designers knowledge of user needs, product functional requirements, operating conditions, cost, quality, and reliability targets. One of the most promising methods for providing timely and accurate information to the designer on an “as-needed” basis is through the use of expert design systems. Such systems promise to bridge the knowledge gap between CAD and CAM and help to incorporate these functions into the overall CIM environment.

Parallel Multi-Cycle LES of an Optical Pent-Roof DISI Engine Under Motored Operating Conditions

2017 ◽  
Author(s):  
Noah Van Dam ◽  
Wei Zeng ◽  
Magnus Sjöberg ◽  
Sibendu Som
Keyword(s):  
Experimental Data ◽  
Direct Injection ◽  
Operating Conditions ◽  
New Strategy ◽  
Long Time ◽  
Order Of Magnitude ◽  
Structure Index ◽  
Number Of Cycles ◽  
The Many ◽  
Direct Injection Spark Ignition

The use of Large-eddy Simulations (LES) has increased due to their ability to resolve the turbulent fluctuations of engine flows and capture the resulting cycle-to-cycle variability. One drawback of LES, however, is the requirement to run multiple engine cycles to obtain the necessary cycle statistics for full validation. The standard method to obtain the cycles by running a single simulation through many engine cycles sequentially can take a long time to complete. Recently, a new strategy has been proposed by our research group to reduce the amount of time necessary to simulate the many engine cycles by running individual engine cycle simulations in parallel. With modern large computing systems this has the potential to reduce the amount of time necessary for a full set of simulated engine cycles to finish by up to an order of magnitude. In this paper, the Parallel Perturbation Methodology (PPM) is used to simulate up to 35 engine cycles of an optically accessible, pent-roof Direct-injection Spark-ignition (DISI) engine at two different motored engine operating conditions, one throttled and one un-throttled. Comparisons are made against corresponding sequential-cycle simulations to verify the similarity of results using either methodology. Mean results from the PPM approach are very similar to sequential-cycle results with less than 0.5% difference in pressure and a magnitude structure index (MSI) of 0.95. Differences in cycle-to-cycle variability (CCV) predictions are larger, but close to the statistical uncertainty in the measurement for the number of cycles simulated. PPM LES results were also compared against experimental data. Mean quantities such as pressure or mean velocities were typically matched to within 5–10%. Pressure CCVs were under-predicted, mostly due to the lack of any perturbations in the pressure boundary conditions between cycles. Velocity CCVs for the simulations had the same average magnitude as experiments, but the experimental data showed greater spatial variation in the root-mean-square (RMS). Conversely, circular standard deviation results showed greater repeatability of the flow directionality and swirl vortex positioning than the simulations.

Controlled inertia tensor of a transformable spacecraft

2021 ◽  
Author(s):  
R.P. Simonyants ◽  
N.A. Alekhin ◽  
V.A. Tarasov
Keyword(s):  
Attitude Control ◽  
Dynamic Properties ◽  
Operating Conditions ◽  
Inertia Tensor ◽  
Simplified Model ◽  
Diagonal Form ◽  
Transformation Mechanism ◽  
External Disturbances ◽  
Type Transformation ◽  
Gravitational Moment

A simplified model of a transformable spacecraft is considered, including a rod-type transformation mechanism with movable weights. The mechanism can be used to adapt the dynamic properties of the spacecraft to the environment or the operating conditions of on-board systems, for example, to counter the moments of external disturbances during attitude control and angular stabilization. By changing the position of the transformation mechanism, the spacecraft inertia tensor can be put in diagonal form, which makes it possible to exclude the force interconnections between the channels and to eliminate the constant component of the gravitational moment. For a simplified model of the transformation mechanism, we establish the analytical dependence of the components of the inertia tensor on the parameters determining the position of the transformation mechanism. It is shown that by adjusting the moving mass, which is 0.5% of the entire spacecraft mass, we obtain the spacecraft configuration that ensures the diagonality of the inertia tensor.

Experiment and analysis on chaotic characteristics vibration mill with variable rotational speed

2021 ◽  
pp. 2150052
Author(s):  
Xiaolan Yang ◽  
Yuan Gao ◽  
Minping Jia
Keyword(s):  
Chaotic Motion ◽  
Average Particle Size ◽  
Engineering Application ◽  
Operating Conditions ◽  
Average Particle ◽  
Maximum Lyapunov Exponent ◽  
Motor Speed ◽  
Low Efficiency ◽  
Motion Characteristics ◽  
Vibration Mill

In an attempt to improve the current low efficiency and high consumption situation of vibration mills, this paper analyses the chaotic motion characteristics of the system and the movement of vibration mill. The complex stiffness-dispersion coupling of the system is also studied, so as to investigate the effect of the system’s chaotic motion characteristics on the efficiency improvement and energy consumption reduction. Based on the ADAMS software, this paper establishes a simplified vibration mill mechanical model, analyzes the singularity and stability of the system, and determines the critical speed at which the vibration motor becomes chaotic according to the bifurcation diagram. Then the chaotic state of the grinding machine with sinusoidal variation in its motor speed is studied based on the Poincaré principle, singular attractor and maximum Lyapunov exponent. Lastly, a 200[Formula: see text]h vibration test on diamond powder with an average particle size of 10 [Formula: see text]m was carried out. Test results under the two operating conditions of variable and constant speeds are compared and analyzed. Our results show that with variable speed the vibration mill achieved higher grinding efficiency but smaller particle grain size. The research elaborated in this paper provides a valuable reference for the engineering application of the chaotic characteristics of vibration mill.

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