Dynamic Velocity Feed-Forward Compensation Control with RBF-NN System Identification for Industrial Robots

A dynamic velocity feed-forward compensation （RBF-NN） dynamic model identification was presented for control （DVFCC） approach with RBF neural network the adaptive trajectory tracking of industrial robots. The proposed control approach combined the advantages of traditional feedback closed-loop position control and computed torque control based on inverse dynamic model. The feed-forward compensator used a nominal robot dynamics as accurate dynamic model and on-line identification with RBF-NN as uncertain part to improve dynamic modeling accu- racy. The proposed compensation was applied as velocity feed-forward by an inverse velocity controller that can con- vert torque signal into velocity in the standard industrial controller. Then, the need for a torque control interface was avoided in the real-time dynamic control of industrial robot. The simulations and experiments were carried out on a gas cutting manipulator. The results show that the proposed control approach can reduce steady-state error, suppress overshoot and enhance tracking accuracy and efficiency in joint space and Cartesian space, especially under high- speed condition.

Research on dynamic error compensation for an armored K type thermocouple

A new method was proposed, in which a high-power CO2 laser modulated by high frequency was used as the driv- ing source to heat up a surface-temperature sensor. The continual beam and the pulsed beam sent out by the same laser could be used in the same system to carry on the static calibration of the radiation thermometer and the dynamic calibration of the temperature sensor to be checked. The frequency-response characteristics of high-speed radiation thermometer surpassed that of the temperature sensor, therefore it could be used as the reference value to calibrate the latter and let system error be cor- rected. Differences in the environment of the sensor installing and the error caused by the change of thermo-physical proper- ty could be avoided. Thus, the difficult problem of traceable dynamic calibration of temperature was solved. In experiment, to obtain the frequency characteristics of the thermocouple and the dynamic performance of the K type thermocouple, which could compensate the dynamic characteristics of the sensor, the sensor was dynamically corrected by using the method, and then the mathematical model was established.

Dynamic compensation for sensors based on particle swarm optimization and realization on LabVIEW

In shock wave＇s pressure testing,a dynamic compensation digital filter is designed based on particle swarm optimization （PSO） algorithm.Dynamic calibration experiment and simulation are conducted for the pressure sensor.PSO algorithm is applied on Matlab platform to achieve optimization according to input and output data of the sensor as well as the reference model,and the global optimal values got by optimization become the parameters of the compensator.Finally,the dynamic compensation filter is established on LabVIEW platform.The experimental results show that the data after processing with the compensation filter truly reflects the input signal.

Research on the Dynamic Model of Spindle Rotation Induced Error Compensation System of Boring and its Simulation

In this paper we address the dynamics of compensation cutting process from both Laplace s frequency domain and the time domain of the first time, using the two computer aided analyzing softwares: MATLAB and SIMULINK. Theoretical analysis and simulation experiments firstly show that not only the systematical stiffness of workpiece, spindle and tools, but also the regenerated coefficient affects the compensation displacement effect. The results show that the SREC is practicable in reality to decease the spindle induced errors in many engineering applications such as hard boring through simulation and the preliminary experiment results.

Dynamic compensation and its application of shock wave pressure sensor

In order to correct the test error caused by the dynamic characteristics of pressure sensor and avoid the influence of the error of sensor＇s dynamic model on compensation results,a dynamic compensation method of the pressure sensor is presented,which is based on quantum-behaved particle swarm optimization（QPSO）algorithm and the mean square error（MSE）.By using this method,the inverse model of the sensor is built and optimized and then the coefficients of the optimal compensator are got.This method is verified by the dynamic calibration with shock tube and the dynamic characteristics of the sensor before and after compensation are analyzed in time domain and frequency domain.The results show that the working bandwidth of the sensor is extended effectively.This method can reduce dynamic measuring error and improve test accuracy in actual measurement experiments.

APPROACH TO IMPROVEMENT OF ROBOT TRAJECTORY ACCURACY BY DYNAMIC COMPENSATION

Some dynamic factors, such as inertial forces and friction, may affect therobot trajectory accuracy. But these effects are not taken into account in robot motion controlschemes. Dynamic control methods, on the other hand, require the dynamic model of robot and theimplementation of new type controller. A method to improve robot trajectory accuracy by dynamiccompensation in robot motion control system is proposed. The dynamic compensation is applied as anadditional velocity feedforward and a multilayer neural network is employed to realize the robotinverse dynamics. The complicated dynamic parameter identification problem becomes a learningprocess of neural network connecting weights under supervision. The finite Fourier series is used toactivate each actuator of robot joints for obtaining training samples. Robot control system,consisting of an industrial computer and a digital motion controller, is implemented. The system isof open architecture with velocity feedforward function. The proposed method is not model-based andcombines the advantages of close-loop position control and computed torque control. Experimentalresults have shown that the method is validatities to improve the robot trajectory accuracy.

Dynamic Simulation and Tension Compensation Research on Subsea Umbilical Cable Laying System

For studying the dynamic performance of subsea umbilical cable laying system and achieving the goal of cable tension and laying speed control,the rigid finite element method is used to discrete and transform the system into a rigid-flexible coupling multi-body system which consists of rigid elements and spring-damping elements.The mathematical model of subsea umbilical cable laying system kinematic chain is presented with the second order Lagrange equation in the joint coordinate system,and dynamic modeling and simulation is performed with ADAMS.The dynamic analysis is conducted assuming the following three statuses:ideal laying,practical laying under wave disturbance,and practical laying with tension compensation.Results show that motion disturbances of the laying budge under sea waves,especially with heaving and pitching,will cause relatively serious fluctuations in cable tension and laying speed.Tension compensation,i.e.,active back tension torque control can restrict continuous tension increasing or decreasing effectively and rapidly,thus avoiding cable breach or buckling.

Symmetrical dynamics of peak current-mode and valley current-mode controlled switching dc-dc converters with ramp compensation

The discrete iterative map models of peak current-mode （PCM） and valley current-mode （VCM） controlled buck converters, boost converters, and buck-boost converters with ramp compensation are established and their dynamical behaviours are investigated by using the operation region, parameter space map, bifurcation diagram, and Lyapunov exponent spectrum. The research results indicate that ramp compensation extends the stable operation range of the PCM controlled switching dc-dc converter to D 〉 0.5 and that of the VCM controlled switching dc-dc converter to D 〈 0.5. Compared with PCM controlled switching dc-dc converters with ramp compensation, VCM controlled switching dc-dc converters with ramp compensation exhibit interesting symmetrical dynamics. Experimental results are given to verify the analysis results in this paper.

A Power Reduction Method for Pilot Channel of LEO Satellite Based on Dynamic Compensation

Since the lower power requirement of code division multiple access(CDMA) than that of other multiple access, the CDMA technology is suitable to be used in low earth orbit(LEO) satellite communication system whose space power is limited due to the small size of satellite. The pilot channel of CDMA technology is very important for earth mobile station(EMS) in LEO system to recover carrier and code, but the power requirement of pilot channel is very higher than that of other channels. In this paper, a power reduction method for pilot channel is proposed. By the new method, the power of pilot channel transmitted from LEO satellite is reduced to a lower level. For improving the signal to noise ratio(SNR) of pilot channel with lower power, coherent integration is employed in EMS at the pre-processing stage. Considering the high dynamic situation of LEO satellite, the long period of time for integration will deteriorate the receiving performance of EMS, therefore, a dynamic compensation module is added to carrier tracking loop against the high dynamic. Meanwhile, the transfer function of the new tracking loop and the condition for steadystate zero error are deduced. Numerical examples are provided to demonstrate effectiveness of the proposed approach.

The dynamic compensation temperature in a kinetic spin-5/2 Ising model on a hexagonal lattice

We present a study of the dynamic behavior of a two-sublattice spin-5/2 Ising model with bilinear and crystal-field interactions in the presence of a time-dependent oscillating external magnetic field on alternating layers of a hexagonal lattice by using the Glauber-type stochastic dynamics.The lattice is formed by alternate layers of spins σ=5/2 and S=5/2.We employ the Glauber transition rates to construct the mean-field dynamic equations.First,we investigate the time variations of the average sublattice magnetizations to find the phases in the system and then the thermal behavior of the dynamic sublattice magnetizations to characterize the nature（first-or second-order） of the phase transitions and to obtain the dynamic phase transition（DPT） points.We also study the thermal behavior of the dynamic total magnetization to find the dynamic compensation temperature and to determine the type of the dynamic compensation behavior.We present the dynamic phase diagrams,including the dynamic compensation temperatures,in nine different planes.The phase diagrams contain seven different fundamental phases,thirteen different mixed phases,in which the binary and ternary combination of fundamental phases and the compensation temperature or the L-type behavior strongly depend on the interaction parameters.

Dynamic requisition, compensation and reclamation of subsided land induced underground coal mining

Following the description of the subsided land treatment methods and the characteristics of the related land reclamation, the necessity and emergency of the land reclamation work is stressed. To cope with the related problems, dynamic prediction of the ground subsidence in different time periods and areas is made based on the laws governing the rock and ground movements and line with a mine’s future mining plan. It is proposed to carry out dynamic management of subsided land reclamation work in mining area, in order to tackle the previous and current issues confronted in the processes of land requisition, compensation and land reclamation. It is intended to provide, through the above-mentioned efforts, the technical and decision-making basis for the mining authorities concerned to better solve the problems relating to land requisition and reclamation in the future, and relocation of villages for facilitating the mining of the underground coal depositing and realizing the sustainable development of mining enterprises.

Adaptive current compensation with nonlinear disturbance observer for single-sided linear induction motor considering dynamic eddy-effect

An adaptive current compensation control for a single-sided linear induction motor(SLIM) with nonlinear disturbance observer was developed. First, to maintain t-axis secondary component flux constant with consideration of the specially dynamic eddy-effect(DEE) of the SLIM, a instantaneously tracing compensation of m-axis current component was analyzed. Second,adaptive current compensation based on Taylor-discretization algorithm was proposed. Third, an effective kind of nonlinear disturbance observer(NDOB) was employed to estimate and compensate the undesired load vibrations, then the robustness of the control system could be guaranteed. Experimental verification of the feasibility of the proposed method for an SLIM control system was performed, and it showed that the proposed adaptive compensation scheme with NDOB could significantly promote speed dynamical response and minimize speed ripple under the conditions of external load coupled vibrations and unavoidable feedback control variables measured errors, i.e., current and speed.

Design to conditioning circuits of dynamic compensation of reactive power in the intelligence voltage controller

The paper introduces one design idea that making use of SCM to control Real-timely the dynamic compensation of reactive power.Firstly,design one Circuit to Sample the voltage and current,and by these datas we can easily calculate the power factor,and Voltage controller in the microcontroller to determine whether input the compensation capacitance according to the size of power factor,the paper also analyzes the principle of capacitance compensation and calculation method. Dynamic compensation for the entire process is quick and accurate.

Compensation：A Synchronic Dynamic Mechanism in Language

In this paper, compensation mechanism—a synchronic dynamic rule in language is postulated and theorized. The rule raises the acceptability of clauses by effecting the positive side of some variations with exceptional expression and offsetting their negative side. This mechanism is determined by the instrumentality and systematicality of language so that its basic principle should be applicable to all exceptional expressions for particular positive effects and thus universal synchronically.

Attitude Stabilization of a Novel Flying Robot by Dynamic Compensation

This paper gives details about the controller design that aims to stabilize the novel twinrotor flying robot, Toruk. Toruk is an experimental test bench to study center of gravity steering, effect of the location of the center of gravity, controller design and implementation, etc. Physical components are also briefly discussed in this paper. Attitude dynamics of the system is inherently unstable. It is stabilized by a regulator. In addition, an observer is designed and utilized to estimate the unmeasured states. Thrust force generated by the propulsion unit is estimated by using the identified mathematical model of the unit. An experimental setup is employed to identify the mathematical model that expresses the relation between the applied input voltage to the propulsion unit and thrust produced by the propeller. Mathematical model for the attitude dynamics of Toruk is built. Then controllability and observability analysis are carried out for the system. Dynamic compensator composed of a state observer and a regulator, is designed on the mathematical model. Physical implementation on the system will be performed.

Novel disturbance compensating dynamic positioning of dredgers based on adaptive backstepping

In order to deal with the dynamic positioning system control problems of dredgers working under strong dredging reaction or harsh environments,an adaptive backstepping method is proposed.Disturbances are estimated and compensated for by the adaptive method without extra sensors on dredging equipment,and the control mechanism is simplified.Adaptive control is used to compensate for the reaction and environmental disturbances on the dredger,so the dredger can maintain the desired position with a minimum error and shock.The proposed adaptive robust controller guarantees the global asymptotic stability of the closed-loop system and rapid position tracking of the dredger.The simulation results show that the proposed controller has superior performance in position tracking and robustness to large disturbances.

Real-time Feed-forward Force Compensation for Active Magnetic Bearings System Based on H∞ Controller

There are two kinds of unbalance vibrations—force vibration and displacement vibration due to the existence of unbalance excitation in active magnetic bearings（AMB） system. And two unbalance compensation methods—closed-loop feedback and open loop feed-forward are presented to reduce the force vibration. The transfer function order of the control system directly influencing the system stability will be increased when the closed-loop method is adopted, which makes the real-time compensation not easily achieved. While the open loop method would not increase the primary transfer function order, it provides conditions for real-time compensation. But the real-time compensation signals are not easy to be obtained in the open loop method. To implement real-time force compensation, a new method is proposed to reduce the force vibration caused by the rotor unbalance on the basis of AMB active control. The method realizes real-time and on-line force auto-compensation based on H∞ controller and one novel feed-forward compensation controller, which makes the rotor rotate around its inertia axis. The time-variable feed-forward compensatory signal is provided by a modified adaptive variable step-size least mean square（VSLMS） algorithm. And the relevant least mean square（LMS） algorithm parameters are used to solve the H∞ controller weighting functions. The simulation of the new method to compensate some frequency-variable and sinusoidal signals is completed by MATLAB programming, and real-time compensation is implemented in the actual AMB experimental system. The simulation and experiment results show that the compensation scheme can improve the robust stability and the anti-interference ability of the whole AMB system by using H∞ controller to achieve close-loop control, and then real-time force unbalance compensation is implemented. The proposed research provides a new control strategy containing real-time algorithm and H∞ controller for the force compensation of AMB system. And the stability of the control system is finally improved.

Eigenstructure assignment of lower-order dynamical compensatorsfor linear systems with unknown inputs

Presents a systematic design method of reduced order dynamical compensator via the parametric representations of eigenstructure assignment for linear system, which provides maximum degree of freedom, and can be easily used for the design of a linear system with unknown inputs under some conditions. Even when these conditions are not satisfied, the lower order dynamical compensator can also be designed under some relaxed conditions. Some examples illustrate that the method is neat, simple and effective.

Auxiliary Service Dynamic Compensation Mechanism Design for Incentivizing Market Participants to Provide Flexibility in China

Because of the rapid growth of new energy and the accompanying considerable uncertainty in the power market,the demand for flexibility in a power sys-tem has risen sharply.In the meantime,the market structure of auxiliary services has changed,resulting in market participants(MPs)benefiting less than expected from providing flexible services.To encourage MPs to provide flexibility,this study proposes a dynamic design framework for an auxiliary service compensation mech-anism.To evaluate the proposed framework,a case study is conducted,examining a peak-shaving service in Liao-ning province in northeast China.First,the operational status and limitations of the typical product,the peak-shaving service,in China’s flexibility auxiliary ser-vices market are analyzed.Then,taking into considera-tion the time value of the flexible products provided by the MPs,a dynamic mechanism for hierarchical compensa-tion of flexibility auxiliary service costs is proposed,and a mathematical model aimed at optimizing the MPs’com-prehensive income is constructed.The results show that,compared with the existing traditional mechanism,the proposed method can effectively guarantee fair remu-neration for the flexibility provider,while easing the tense supply-demand relationship in the flexibility market.Index Terms—Power system flexibility,auxiliary ser-vices market,peak shaving auxiliary service,differenti-ated operation scenario,dynamic hierarchical compensa-tion mechanism.