Robust Damage-Mitigating Control of Mechanical Systems: Experimental Validation on a Test Apparatus

1999 ◽  
Vol 121 (3) ◽  
pp. 377-385 ◽  
Author(s):  
Hui Zhang ◽  
Asok Ray
Keyword(s):  
High Performance ◽  
Dynamic Performance ◽  
Significant Loss ◽  
Control Synthesis ◽  
Test Apparatus ◽  
Material Degradation ◽  
Domain Identification ◽  
Damage Reduction ◽  
Three Degree Of Freedom ◽  
Component Service Life

The goal of damage-mitigating control is to achieve high performance of operating machinery without overstraining the mechanical structures and the potential benefit is an increase in the component service life with no significant loss of performance. This paper presents the design of a test apparatus, the synthesis of a damage-mitigating control system, and the results of experimentation where the objective is to demonstrate the concept of fatigue damage reduction as an extension of multivariable robust feedback control. The test apparatus is built upon a three-degree-of-freedom, two-input three-output mechanical structure. The methodology of the damage-mitigating control synthesis is built upon the principles of: (i) frequency-domain identification of the plant dynamics and modeling of uncertainties in the state-space setting; and (ii) robust control based on the H∞ approach by taking both plant dynamic performance and material degradation of structural components into consideration. Case studies on the test apparatus indicate that fatigue life of specimens can be substantially extended with no appreciable degradation in the dynamic performance of the mechanical system.

Modeling and Experimental Evaluation of Asymmetric Pantograph Dynamics

1988 ◽  
Vol 110 (2) ◽  
pp. 168-174 ◽  
Author(s):  
S. D. Eppinger ◽  
D. N. O’Connor ◽  
W. P. Seering ◽  
D. N. Wormley
Keyword(s):  
High Performance ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Dynamic Testing ◽  
Dynamic Performance ◽  
Performance Model ◽  
Degree Of Freedom ◽  
Additional Degree ◽  
Three Degree Of Freedom ◽  
Two Degree Of Freedom

High-performance pantograph design requires control of pantograph dynamic performance. Many pantograph dynamic models developed to aid in the design process have employed two degrees of freedom, one for the head mass and one for the frame. In this paper, the applicability of these models to symmetric and asymmetric pantograph designs is reviewed. Two degree-of-freedom models have been shown to be appropriate to represent a number of symmetric pantograph designs. To represent the asymmetric designs considered in this paper, an additional degree of freedom representing frame dynamics has been introduced to yield a three degree-of-freedom nonlinear dynamic performance model. The model has been evaluated with experimental data obtained from laboratory dynamic testing of an asymmetric pantograph.

Research on the New Missile Actuation System with Dual Independent Closed-Loop

2014 ◽  
Vol 551 ◽  
pp. 337-343
Author(s):  
Hui Chen ◽  
Yong Ling Fu ◽  
Juan Chen ◽  
He Song Liu
Keyword(s):  
High Performance ◽  
Closed Loop ◽  
Dynamic Performance ◽  
Actuation System ◽  
High Penetration ◽  
Low Energy Consumption ◽  
Penetration Ability ◽  
Important Direction ◽  
And Performance ◽  
Missile System

With the development of the advanced precision-guided missile and anti-missile system, high precision, high penetration ability and Low energy consumption have become an important direction for the missile. A new missile electro-hydraulic actuation system with dual independent closed-loop is put forward with the trend of high performance and energy-saving, and then the operating principle and process are discussed. Finally the accurate mathematical model is established, and the influence of the different basic pressure on the dynamic performance is analyzed. The simulation results show that the new proposed scheme has made great improvements in reducing the zero-control current of the system, but the efficiency and performance of the actuation system should be considered integrated due to the decrease of the dynamic performance, so it is practical for the future development of the missile electro-hydraulic actuation system.

scholarly journals Effect of Thermal Processing on Carotenoids and Folate Changes in Six Varieties of Sweet Potato (Ipomoes batata L.)

Foods ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 215 ◽  
Author(s):  
Zhijun Pan ◽  
Yiming Sun ◽  
Fangyuan Zhang ◽  
Xinbo Guo ◽  
Zhihua Liao
Keyword(s):  
Sweet Potato ◽  
Thermal Processing ◽  
Thermal Process ◽  
High Performance ◽  
Vitamin A Deficiency ◽  
Significant Loss ◽  
Thermal Impact ◽  
Total Carotenoids ◽  
Microbial Assay ◽  
Β Carotene

Carotenoids and folate are two mandatory supplying micronutrients for children or pregnant women. Inadequate intake of these two nutrients was relevant to a higher mortality of both children and pregnancies. This study is intended to investigate the thermal impact on the changes of carotenoids and folate in sweet potato roots (SPRs). Carotenoids were identified by high performance liquid chromatography (HPLC) while the folate was estimated using a microbial assay. An obvious decline was observed in total carotenoids after heating. Nevertheless, the content of provitamin compound β-carotene exhibited incredible stability during steaming and α-carotene multiplied in certain varieties, evidencing that SPRs could be an efficient way for addressing Vitamin A deficiency (VAD). As for the total folate contents, two varieties were found no significant loss after thermal process while the others showed a significant decrease. The results indicated that steaming process led to generally loss of both carotenoids and folate while the α-carotene and β-carotene were well preserved. The information provided by this study might help with enhancing the food quality in processing industry and the understanding in the nutrition changes during steaming.

The Studying Fabrication and Application of the Multifunctional Frozen Triaxial Test Apparatus

2013 ◽  
Vol 353-356 ◽  
pp. 388-391
Author(s):  
Shi Yin Zhang
Keyword(s):  
Triaxial Test ◽  
High Performance ◽  
Frozen Soil ◽  
Load Test ◽  
Test Apparatus ◽  
Test Parameter ◽  
New Type ◽  
Triaxial Creep ◽  
Set Up ◽  
Triaxial Creep Test

The frozen soil triaxial test apparatus is the basic equipment to study the mechanics property of the frozen soil. According to the norm of frozen soil test and the construction character of the present mine, the high-performance frozen soil triaxial test apparatus is made which could be used for many type tests, such as the static triaxial shear test, the dynamic triaxial test, the triaxial creep test, the routine triaxial strain route test, the routine triaxial proportion coordination test, the routine triaxial recycle load test, the routine triaxial concretion test and so on. The apparatus can realize the high surround pressure. During the test progress, the test parameter can be set up and the test date can be collected by the computer. The frozen soil triaxial test apparatus is a new type triaxial test apparatus.

Life extending controller design for reusable rocket engines

2001 ◽  
Vol 105 (1048) ◽  
pp. 315-322 ◽  
Author(s):  
A. Ray ◽  
M. S. Holmes ◽  
C. F. Lorenzo
Keyword(s):  
Controller Design ◽  
Space Shuttle ◽  
Rocket Engine ◽  
Design Procedure ◽  
Fuel Mixture ◽  
Significant Loss ◽  
Chamber Pressure ◽  
Control Synthesis ◽  
Rocket Engines ◽  
Mixture Ratio

Abstract The goal of life extending control (LEC) is to enhance structural durability of complex mechanical systems, such as aircraft, spacecraft, and energy conversion devices, without incurring any significant loss of performance. This paper presents a concept of robust life-extending controller design for reusable rocket engines, similar to the Space Shuttle Main Engine (SSME), via damage mitigation in both fuel and oxidiser turbines while achieving the required performance for transient responses of the main combustion chamber pressure and the oxidant/fuel mixture ratio. The design procedure makes use of a combination of linear robust control synthesis and nonlinear optimisation techniques. Results of simulation experiments on the model of a reusable rocket engine are presented to this effect.

scholarly journals Optimization of the Treatment of Wheat Samples for the Determination of Phytic Acid by HPLC with Refractive Index Detection

2009 ◽  
Vol 92 (3) ◽  
pp. 873-878 ◽  
Author(s):  
Rosa Amaro ◽  
Miguel Murillo ◽  
Zurima Gonzlez ◽  
András Escalona ◽  
Lus Hernández
Keyword(s):  
Refractive Index ◽  
High Performance Liquid Chromatography ◽  
Phytic Acid ◽  
High Performance ◽  
Substantial Improvement ◽  
Significant Loss ◽  
Phytic Acid Content ◽  
Extraction Step ◽  
Refractive Index Detection

Abstract The treatment of wheat samples was optimized before the determination of phytic acid by high-performance liquid chromatography with refractive index detection. Drying by lyophilization and oven drying were studied; drying by lyophilization gave better results, confirming that this step is critical in preventing significant loss of analyte. In the extraction step, washing of the residue and collection of this water before retention of the phytates in the NH2 Sep-Pak cartridge were important. The retention of phytates in the NH2 Sep-Pak cartridge and elimination of the HCl did not produce significant loss (P = 0.05) in the phytic acid content of the sample. Recoveries of phytic acid averaged 91, which is a substantial improvement with respect to values reported by others using this methodology.

Stability of Donepezil in an Extemporaneously Prepared Oral Liquid

2006 ◽  
Vol 19 (5) ◽  
pp. 282-285 ◽  
Author(s):  
Weeranuj Yamreudeewong ◽  
Eric Kurt Dolence ◽  
Deborah Pahl
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Storage Time ◽  
Microbial Growth ◽  
Storage Period ◽  
Significant Loss ◽  
Ambient Room Temperature ◽  
Oral Liquid ◽  
Liquid Preparation ◽  
The Stability

The stability of donepezil in an extemporaneously prepared oral liquid was studied. An aqueous liquid formulation of donepezil was prepared by reconstituting the powder from triturated 5-mg tablets with equal amounts of deionized water and 70% sorbitol solution with an expected donepezil concentration of 1 mg/mL. Polyethylene terephthalate plastic bottles containing donepezil liquid preparation were stored at ambient room temperature (22° C-26° C) and in the refrigerator (4° C-8° C). After a storage time of 1, 2, 3, and 4 weeks, donepezil liquid samples were analyzed in triplicate for donepezil concentrations by high-performance liquid chromatography. The concentrations of donepezil were found to be within the acceptable limit (± 10% of the initial concentration) in all test samples, which indicated that donepezil liquid preparation was stable at room temperature and in the refrigerator for up to 4 weeks. In addition, our study findings indicated that there was no microbial growth in the extemporaneously prepared donepezil liquid preparation after a storage period of 4 weeks in the refrigerator. In summary, the results of our study revealed that donepezil is stable (no significant loss of donepezil concentration and no microbial growth) in an extemporaneously prepared oral liquid when stored in the refrigerator for up to 4 weeks.

Hybrid Position/Force Control for a RRR 3-DoF Manipulator

2011 ◽  
Vol 48-49 ◽  
pp. 589-592 ◽  
Author(s):  
Shi Xiang Tian ◽  
Sheng Ze Wang
Keyword(s):  
Force Control ◽  
Free Space ◽  
High Performance ◽  
Degree Of Freedom ◽  
End Effector ◽  
Robot Trajectory ◽  
Simulation Results ◽  
Trajectory Following ◽  
Three Degree Of Freedom

In this paper, a novel hybrid position/force controller has been proposed for a three degree of freedom (3-DOF) of robot trajectory following that is required to switch between position and force control. The whole controller consists of two components: a positional controller and a force controller. Depending on whether the end-effector is in free space or in contact with the environments during work, the two subcontrollers run simultaneously to guide the manipulator tracking in free space and constraint environments. After the principle and stability of the controller are briefly analyzed, simulation results verify that the proposed controller attains a high performance.

Design of Single-Axis Control System Based on FM354

2014 ◽  
Vol 926-930 ◽  
pp. 1289-1292
Author(s):  
Cong Qiu ◽  
Wang Yong He ◽  
Bo Tian
Keyword(s):  
Control System ◽  
Motion Control ◽  
High Performance ◽  
Position Control ◽  
Dynamic Performance ◽  
Current Loop ◽  
Loop Control ◽  
Precise Position ◽  
Ac Servo System ◽  
Ac Servo

AC servo system has been widely used in many fields with its high performance and the fast development of intelligent control strategy. Targeted at the single-axis motion control applications in industrial automation, a kind of single-axis motion control system, based on FM354 controlled by S7-300 PLC, is designed. The system consists of three to the position, speed and current closed-loop control to achieve precise position control. The position loop is implemented by FM354. The speed loop and current loop are encapsulated in the servo driver. Through monitoring and comparing the dynamic performance with traditional systems, it can find out the bench runs smoothly and positioning accurately, perfectly meeting the technological and application requirements. It also can be applied to a variety of occasions and used for multi-axis extension.

The Brazing Furnace Intelligent Control Scheme Research of Application

2014 ◽  
Vol 602-605 ◽  
pp. 1135-1138
Author(s):  
Cai Hong Yao ◽  
Xing Jia Jiang
Keyword(s):  
State Space ◽  
Pid Control ◽  
Performance Index ◽  
High Performance ◽  
State Feedback ◽  
Simulation Analysis ◽  
Dynamic Performance ◽  
Optimum Control ◽  
Actual System ◽  
Control Scheme

For the brazing furnace work system with time-varying, hysteresis and nonlinearity characteristic, the traditional PID control cannot meet the requirements of high-performance. Fuzzy self-tuning PID control scheme, can effectively overcome the interference effect, has good adaptability. But the based on modern control theory state space analytic method uses state feedback, not only promulgating the system internal structural property, to realize the optimum control to system’s compound performance index. By combining state feedback and PID control of the respective advantages, determined the brazing furnace temperature system’s optimum control scheme. Either the simulation analysis or actual system operation fully explaining fuzzy intelligent designs of the tuning PID and the optimal control scheme based on state space method have improved significantly the system's steady-state and dynamic performance index.

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