WRIST FORCE SENSOR'S DYNAMIC PERFORMANCE CALIBRATION BASED ON NEGATIVE STEP RESPONSE

Negative step response experimental method is used in wrist force sensor＇s dynamic performance calibration. The exciting manner of negative step response method is the same as wrist force sensor＇s load in working. This experimental method needn＇t special experiment equipments. Experiment＇s dynamic repeatability is good. So wrist force sensor＇s dynamic performance is suitable to be calibrated by negative step response method. A new correlation wavelet transfer method is studied. By wavelet transfer method, the signal is decomposed into two dimensional spaces of time-frequency. So the problem of negative step exciting energy concentrating in the low frequency band is solved. Correlation wavelet transfer doesn＇t require that wavelet primary function be orthogonal and needn＇t wavelet reconstruction. So analyzing efficiency is high. An experimental bench is designed and manufactured to load the wrist force sensor orthogonal excitation force/moment. A piezoelectric force sensor is used to setup soft trigger and calculate the value of negative step excitation. A wrist force sensor is calibrated. The pulse response function is calculated after negative step excitation and step response have been transformed to positive step excitation and step response. The pulse response function is transferred to frequency response function. The wrist force sensor＇s dynamic characteristics are identified by the frequency response function.

INFLUENCE OF SHOT AND STEP RESPONSE ON PARAMETRIC SENSITIVITY UNDER THE STIMULUS-RESPONSE OF ANALYSIS

Shot and step response measurements were carried out with inert bed and adsorption bed both under iso-thermal conditions.Parameter values were determined from a time domain analysis of the measured inputand response signal.Sensitivity test in the parameter values showed that shot response measurements maygive more reliable parameter values than step measurements.Since Kubin[1]and Kucera[2]proposed a parameter estimation technique based on a moment methodfor adsorption system,attention has been focused on dynamic input-output measurements with variouspacked bed systems for the parameter estimation.The object of this work is to compare shot and step re-sponse measurements and see which measurement gives more reliable parameter values.

Criteria for Response Monotonicity Preserving in Approximation of Fractional Order Systems

In approximation of fractional order systems,a significant objective is to preserve the important properties of the original system.The monotonicity of time/frequency responses is one of these properties whose preservation is of great importance in approximation process.Considering this importance,the issues of monotonicity preservation of the step response and monotonicity preservation of the magnitude-frequency response are independently investigated in this paper.In these investigations,some conditions on approximating filters of fractional operators are found to guarantee the preservation of step/magnitude-frequency response monotonicity in approximation process.These conditions are also simplified in some special cases.In addition,numerical simulation results are presented to show the usefulness of the obtained conditions.

Simple PID Parameter Tuning Method Based on Outputs of the Closed Loop System

Most of the existing PID parameters tuning methods are only effective with pre-known accurate system models, which often require some strict identification experiments and thus infeasible for many complicated systems. Actually, in most practical engineering applications, it is desirable for the PID tuning scheme to be directly based on the input-output response of the closed-loop system. Thus, a new parameter tuning scheme for PID controllers without explicit mathematical model is developed in this paper. The paper begins with a new frequency domain properties analysis of the PID controller. After that, the definition of characteristic frequency for the PID controller is given in order to study the mathematical relationship between the PID parameters and the open-loop frequency properties of the controlled system. Then, the concepts of M-field and θ-field are introduced, which are then used to explain how the PID control parameters influence the closed-loop frequency-magnitude property and its time responses. Subsequently, the new PID parameter tuning scheme, i.e., a group of tuning rules, is proposed based on the preceding analysis. Finally, both simulations and experiments are conducted, and the results verify the feasibility and validity of the proposed methods. This research proposes a PID parameter tuning method based on outputs of the closed loop system.

First order dynamics approaching of broiler chicken deep body temperature response to step changes in ambient temperature

Traditional environmental control methods for poultry housing which rely solely on environmental factors fall short in meeting thermal and physiological needs of the animals.New methods are needed that factor in the physiological needs and responses of the animals in order to maximize well-being of the animals and minimize heat stress.Deep body temperature(DBT)has been shown in the literature to be a strong indicator of heat stress,therefore studies are needed that help us gain a deeper understanding of the relationship between this variable and environmental conditions.The aim of this study was to identify the order of the dynamic response of poultry DBT to large step changes in ambient temperature(AT).Temperature steps had to be big enough to take the chickens out of their homeothermic zone.A total of 46 DBT/AT data sets with 23 upward AT steps and 23 downward AT steps were obtained using a biotelemetry system,and involving three chickens.DBT responses of individual chickens to step changes in AT were found to have a 0.88 average Pearson correlation suggesting consistency in chickens’responses to the same stimuli(p<0.0005).The data indicated that DBT responses to AT followed a first order behavior in most cases with an average time constant of 1.6 h,and the curve fitting method was used to validate this observation.There was a 0.88 average correlation between DBT model and measured data(p<0.0005).These results indicate statistical significance in the data used and the model derived from it.In conclusion,it is reasonable to assume that the dynamic response of poultry DBT to large step changes in ambient temperature follows a first order model.Although further studies are needed to more fully derive the model,this study provided a stepping-stone towards gaining a better understanding of the relationship between DBT and AT,therefore taking us one step closer towards making optimal management and risk assessment decisions that are based on physiological needs of the chickens.

Toxicological effects of TiO_(2) nanoparticles on plant growth promoting soil bacteria

Emerging contaminants like metal nanoparticles get introduced into soil through different routes.Toxic effects of these contaminants on plant growth-promoting bacteria(PGPB),which influence plant productivity,can be detrimental to soil health.Titanium dioxide is one of the most produced nanomaterials in the world and therefore potentially the most released nanoform in soil.The objective of this study was to evaluate the toxic effects of titanium dioxide nanoparticles(TiO2 NPs)on plant growth-promoting bacteria.Three types of PGPB,viz.,nitrogen fixers,phosphate solubilizers and biofilm formers were exposed to TiO2 NPs.Our results suggest that direct contact of the bacteria with these NPs is inhibitory as compared to when these bacteria are growing in laboratory nutrient media in the presence of NPs.The inhibitory effect did not follow a linear dose response but instead showed a pronounced step response.Soils with their varying characteristics may not afford the same protection to bacteria as laboratory nutrient media and thus TiO2 NPs may cause some sensitive PGPB to disappear from soil.The resultant shift in bacterial community composition may affect ecosystem functioning.

On palaeogeographic map

The palaeogeographic map is a graphic representation of physical geographical character- istics in geological history periods and human history periods. It is the most important result of palaeogeographic study. The author, as the Editor-in-Chief oflournal of Palaeogeography, Chinese Edition and English Edition, aimed at the problems of the articles submitted to and published in the]ournal of Palaeogeography in recent years and the relevant papers and books of others, and integrated with his practice of palaeogeographic study and mapping, wrote this paper. The content mainly includes the data of palaeogeographic mapping, the prob- lems of palaeogeographic mapping method, the ＂Single factor analysis and multifactor comprehensive mapping method ---- Methodology of quantitative lithofacies palae- ogeography＇, i.e., the ＂4 steps mapping method＂, the nomenclature of each palaeogeographic unit in palaeogeographic map, the explanation of each palaeogeographic unit in palae- ogeographic map, the explanation of significance of palaeogeographic map and palae- ogeographic article, the evaluative standards of palaeogeographic map and palaeogeographic article, and the self-evaluation. Criticisms and corrections are welcome. 2016 China University of Petroleum {Beijing）. Production and hosting by Elsevier B.V. on behalf of China University of Petroleum （Beijing）. This is an open access article under