Kinematic response of industrial robot with uncertain-but-bounded parameters using interval analysis method

Jinhui Wu,Xu Han,Yourui Tao 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

The uncertain parameters of the deviation in link dimensions and joint clearances caused by manufacturing and assembling errors have a strong impact on the degree of accuracy of the industrial robot. Understanding how these uncertain parameters influence the kinematic response of the industrial robot is critical for design. In this paper, the interval method is used for analysing the kinematic response of the industrial robot with uncertain-but-bounded parameters. The interval used for describing the uncertain parameters is estimated by the grayscale theory. The Denavit-Hartenberg (D-H) method is used for establishing the kinematic model of a 6-degree-of-freedom industrial robot. The kinematic response of the industrial robot calculated by the interval method with uncertain parameters is compared with the results obtained by the probabilistic approach. The comparison results show that the upper or lower bound obtained by interval method is far away from the ideal kinematic response than that obtained by the probabilistic approach. That is a true portrayal of the essence of interval method and probabilistic approach. The research contributes to choose the tolerance zone of uncertain parameters, such as the link dimensions and joint clearances, during the design process of industrial robots.

Improvement of batch crystallization control under uncertain kinetic parameters by model predictive control

Aritsara Saengchan,Paisan Kittisupakorn,Woranee Paengjuntuek,Amornchai Arpornwichanop 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.3

As the widespread use of a batch crystallization process inmany industries, finding an optimal operating condition and effective control strategy are significant for improving product quality and downstream operations. To achieve these, an accuratemodel is required to predict the process behavior and to design an effective and robust controller. However, due to unknown disturbances and batch-to-batch variations, the kinetic parameters obtained from experimental study may not represent the real process resulting in poor control and estimation performances. In this work, improvement of batch crystallization control of a potassium sulfate production under uncertain kinetic parameters has been proposed. An extended Kalman filter (EKF) has been designed to estimate uncertain parameters and unmeasurable states. An optimization model based feedback controller known as Model Predictive Control (MPC) technique has been implemented to achieve the desired crystal size distribution (CSD) subject to a product quality constraint i.e., the requirement of seeded crystal size. Simulation results demonstrate that the robustness of the batch crystallizer control satisfying the requirement of crystal quality has been improved by the MPC control integrated with the EKF in the presence of un-measurable states and uncertain parameters.

LFT Modeling and Robust Stability Analysis of Missiles with Uncertain Parameters

HOU Zhen-qian,LIANG Xiao-geng,WANG Wen-zheng,LI Rui 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2

The structured singular value (μ) analysis based method has many advantages for the robust stability analysis of missiles with uncertain parameters. Nevertheless, the present linear fractional transformation (LFT) modeling process, which is the basis of μ analysis, is complex, and not suitable for automatic implementation; on the other hand, μ analysis requires a large amount of computation, which is a burden for large-scale application. A constructive procedure, which is computationally more efficient, and which may lead to a lower order realization than existing algorithms, is proposed for LFT modeling. To reduce the calculation burden, an analysis method is developed, based on skew μ. On this basis, calculation of the supremum of μ over a fixed frequency range converts into a single skew μ value calculation. Two algorithms are given, to calculate the upper and lower bounds of skew μ, respectively. The validity of the proposed method is verified through robust stability analysis of a missile with real uncertain parameters.

Adaptive Synchronization of Time Delay Chaotic Systems with Uncertain and Unknown Parameters via Aperiodically Intermittent Control

Yuangan Wang,Xingpeng Zhang,Liping Yang,Hong Huang 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.3

Time delay and uncertainty are the two common phenomena in nonlinear systems, which seriously influence the control and synchronization of nonlinear systems. In this paper, an adaptive intermittent control strategy is proposed to realize the synchronization of time delay chaotic systems with uncertain and unknown parameters. For the uncertain and unknown parameters, some sufficient conditions for complete synchronization are derived based on the stability theory. In the part of numerical simulation, two cases of linear and non-linear delay are discussed, which both show the effectiveness of the theoretical results.

Seismic fragility analysis of a buried pipeline structure considering uncertainty of soil parameters

Yoon, Sungsik,Lee, Do Hyung,Jung, Hyung-Jo Elsevier 2019 The International journal of pressure vessels and Vol.175 No.-

<P><B>Abstract</B></P> <P>In this study, the seismic fragility analysis for a buried gas pipeline of API 5L X65 was performed considering the uncertainty of soil parameters. For this purpose, nonlinear time history analyses were carried out for the pipeline considering soil-pipeline interaction represented by beam on nonlinear Winkler foundation model. A total of 12 input ground motions were employed and four different analytical cases were considered to evaluate the effect of the uncertainty of soil parameters. The four cases proved that uncertainty of soil parameters needs to be taken into account for the assessment of the pipeline response. Using results of the nonlinear time history analyses, seismic fragility analyses were conducted in accordance with three damage states. Analytical predictions indicated that seismic fragility curves with the uncertainty of soil parameters exhibit higher failure probability than those without the uncertainty. It is thus concluded that the present study is promising for the exploration of the seismic fragility analysis considering the uncertainty of soil parameters.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Seismic fragility analysis has been carried out for a buried gas pipeline considering uncertainty of soil parameters. </LI> <LI> Beam on nonlinear-Winkler foundation model was utilized for soil-pipeline interaction. </LI> <LI> An efficient Monte Carlo Simulation employing Latin Hypercube Sampling was adopted. </LI> <LI> Unit-weight has been identified as dominant factor affecting the behavior of pipeline. </LI> <LI> Seismic fragility curve that takes into account the uncertainty of soil parameters was more vulnerable to earthquakes. </LI> </UL> </P>

Tracking Control Design for a Bilinear Control System With Unstable and Uncertain Internal Dynamics Using Adaptive Backstepping

Khozin Mu’tamar,Janson Naiborhu,Roberd Saragih,Dewi Handayani 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.9

A non-minimum phase system has unstable zero internal dynamics. Even though the system’s output has stabilised, the state variables of the internal dynamics continue to grow indefinitely. Uncertain parameters in the internal dynamics make their behaviour even more unpredictable. In this article, we solve the tracking problem for a bilinear control system with unstable internal dynamics and uncertain parameters using adaptive backstepping. The bilinear control system is transformed using input–output feedback linearisation to normal form. The unstable internal dynamics containing uncertain parameters are first stabilised using the external dynamics as a virtual control. The external dynamics are then stabilised using other state variables in the external dynamics; the final system uses the actual control function. Numerical simulations are performed to demonstrate the proposed control’s technical implementation and performance. A robustness test is conducted analytically and numerically to understand the control function’s tolerance to uncertain parameters. The simulation results show that the control function successfully solves tracking problems in non-minimum phase systems. Using the integral absolute error criterion, we also determine the range of uncertain parameter values for which the control function works satisfactorily.

Eigenvalue problems of rotor system with uncertain parameters

Bao-Guo Liu 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.1

A general method for investigating the eigenvalue problems of a rotor system with uncertain parameters is presented in this paper. The recurrence perturbation formulas based on the Riccati transfer matrix method are derived and used for calculating the first- and secondorder perturbations of eigenvalues and their respective eigenvectors for the rotor system with uncertain parameters. In addition, these formulas can be used for investigating the independent, and repeated, as well as the complex eigenvalue problems. The general method is called the Riccati perturbation transfer matrix method (Riccati-PTMM). The formulas for calculating the mean value, variance, and covariance of the eigenvalues and eigenvectors of the rotor system with random parameters are also given. Riccati-PTMM is used for calculating the random eigenvalues of a simply supported Timoshenko beam and a test rotor supported by two oil bearings. The results show that the method is accurate and efficient.

Path Following Controller Design for an Underactuated Hovercraft with External Disturbances

Dinis Lu,Wei Xie,David Cabecinhas,Rita Cunha,Carlos Silvestre 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10

This paper addresses the problem of path following control for an underactuated hovercraft in the presence of external disturbances and uncertain parameters. By using the backstepping technique, a path following controller is proposed which is able to steer the hovercraft to a neighborhood of a desired path, obtaining global practical stability. In order to make the vehicle robust to external disturbances and uncertain vehicle parameters, a group of disturbance and linear damping coefficients estimators are designed. Simulation and experimental results are presented and analyzed, validating the efficiency of the proposed control strategy.

Tuning ADRC for Multi-Variable System Based on Existing PID Parameters

Chunzhe Zhao,Yali Xue,Chun-E Huang 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10

Due to the long-time engineering practice, the existing PID controllers and their parameters contain the valuable information about the models of the industrial processes. Such information is absorbed to simplify the design and tuning process of the active disturbance rejection controller (ADRC) in this study. If one channel of the multivariable system is stabilized by PID, then ADRC can be built to replace the PID scheme, and the ADRC parameters can be calculated from the PID parameters. This technique can be operated channel by channel until all channels are stabilized by ADRC, which is verified by simulations. Moreover, the simulations imply that the presented ADRC design and tuning method can generate the feasible parameters efficiently for the plants with unknown models.

Robust Synchronization of Dynamical Network with Impulsive Disturbances and Uncertain Parameters

Cong Zheng,Jinde Cao 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.4

In this paper, we investigate robust global exponential synchronization of an impulsive complex dynamical network with uncertain parameters. The new impulse proposed is added on the coupled states and is relative not only with the coupled states at the current impulsive time instants but also with ones at the previous impulsive time instants. Some sufficient conditions are derived to ensure robust exponential synchronization of the presented impulsive dynamical network by using the stability analysis for impulsive delay systems. The obtained results extend the existed ones. A numerical example is finally exploited to show the effectiveness of the obtained results.