An Analysis Framework for Evaluating Dropout Compensation Strategies in Wireless Servo Systems

Author(s):  
Paul A. Kawka ◽  
Andrew G. Alleyne

This paper presents an approach for analyzing the performance of dropout compensation strategies for linear servo control systems operating over communication channels with losses. A loss of communication causes the normal control action to be replaced by an appropriately designed dropout compensation action. A linear matrix inequality based approach is given for examining H∞ and/or H2 performance of wireless feedback systems using dropout compensation where we assume a two-state Markov model for the communication network. To illustrate the analysis method, we introduce two specific data dropout compensation schemes: zero order hold and estimation. These two schemes are compared in simulation and experiment to validate the effectiveness of the performance analysis.

Author(s):  
Geng Wang ◽  
Renjing Gao ◽  
Qi Wang ◽  
Shutian Liu

Electromagnetic linear actuators (ELAs) may be confronted with unsatisfactory performance when subjected to overheating. Therefore, it is significant to clarify its thermal characteristics and design the thermal performance requirements. A thermal analysis method based on multiphysics coupling model was presented, which uses the non-simplified loss distribution as the heat source to calculate the temperature field, adjusts the material properties by temperature, and considers the interaction between motion (including impact) and loss. More importantly, an improved universal equivalent winding to satisfy the condition of real compact concentrated winding was developed. Finally, the validity of this approach was verified through the experiment, and the regularity of temperature was summarized. The results show that the error of simulation and experiment is less than 6% and the permissible continuous operation frequency is no more than 30 Hz. The approach proposed in this paper can be employed not only to the ELA, but also to the design and analysis a wide range of electromagnetic machines.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Lina Rong ◽  
Chengda Yu ◽  
Pengfei Guo ◽  
Hui Gao

The fault detection problem for a class of wireless networked control systems is investigated. A Bernoulli distributed parameter is introduced in modeling the system dynamics; moreover, multiple time delays arising in the communication are taken into account. The detection observer for tracking the system states is designed, which generates both the state errors and the output errors. By adopting the linear matrix inequality method, a sufficient condition for the stability of wireless networked control systems with stochastic uncertainties and multiple time delays is proposed, and the gain of the fault detection observer is obtained. Finally, an illustrated example is provided to show that the observer designed in this paper tracks the system states well when there is no fault in the systems; however, when fault happens, the observer residual signal rises rapidly and the fault can be quickly detected, which demonstrate the effectiveness of the theoretical results.


2013 ◽  
Vol 321-324 ◽  
pp. 1858-1862 ◽  
Author(s):  
Li Sheng Wei ◽  
Zhi Hui Mei ◽  
Ming Jiang

This study focus on α-Stability constraints for uncertain networked control systems (NCSs) subject to disturbance inputs, where the network transmission is connected with time-delay and packet dropout. The overall NCSs model is derived. In order to obtain much less conservative results, the sufficient condition for feasibility is presented in term of 2nd Lyapunov stability theory and a set of linear matrix inequalities (LMIs). This LMI approach can be the optimization problem of computation of the maximal allowed bound on the time-delay for NCSs.


1981 ◽  
Vol 103 (3) ◽  
pp. 173-180 ◽  
Author(s):  
L. M. Sweet

This paper is a review of current research on applications of control systems and theory to achieve energy conservation in automotive vehicles. The development of internal combustion engine control systems that modulate fuel flow, air flow, ignition timing and duration, and exhaust gas recirculation is discussed. The relative advantages of physical and empirical models for engine performance are reviewed. Control strategies presented include optimized open-loop schedule type systems, closed-loop feedback systems, and adaptive controllers. The development of power train and hybrid vehicle control systems is presented, including controllers for both conventional transmissions and those employing flywheel energy storage.


2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Qixin Zhu ◽  
Hongli Liu ◽  
Yiyi Yin ◽  
Lei Xiong ◽  
Yonghong Zhu

Mechanical resonance is one of the most pervasive problems in servo control. Closed-loop simulations are requisite when the servo control system with high accuracy is designed. The mathematical model of resonance mode must be considered when the closed-loop simulations of servo systems are done. There will be a big difference between the simulation results and the real actualities of servo systems when the resonance mode is not considered in simulations. Firstly, the mathematical model of resonance mode is introduced in this paper. This model can be perceived as a product of a differentiation element and an oscillating element. Secondly, the second-order differentiation element is proposed to simulate the resonant part and the oscillating element is proposed to simulate the antiresonant part. Thirdly, the simulation approach for two resonance modes in servo systems is proposed. Similarly, this approach can be extended to the simulation of three or even more resonances in servo systems. Finally, two numerical simulation examples are given.


Author(s):  
Liruo Zhang ◽  
Sing Kiong Nguang ◽  
Shen Yan

This paper investigates the event-triggered H∞ control for networked control systems under the denial-of-service (DoS) attacks. First, a novel system model is established considering random, time-constraint DoS attacks. Second, an event-triggered scheme including an off-time is proposed to reduce the unnecessary occupation of network resources, with which a prescribed minimum inter-triggering time is guaranteed and Zeno problem is avoided. Third, sufficient conditions for the existence of an event-triggered controller which ensures the exponential stability of the closed-loop system with desired H∞ performance are formulated in linear matrix inequalities (LMIs). Finally, the effectiveness of the proposed method is examined by two illustrative examples, where a real communication network based on the ZigBee protocol is utilized.


Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Hao Wang ◽  
Shousheng Xie ◽  
Weixuan Wang ◽  
Lei Wang ◽  
Jingbo Peng

The problem of unmeasured parameters estimation for distributed control systems is studied in this paper. The Takagi–Sugeno fuzzy model which can appropriate any nonlinear systems is employed, and based on the model, an observer-based fuzzy H∞ filter which has robustness against time-delay, external noise, and system uncertainties is designed. The sufficient condition for the existence of the desired filter is derived in terms of linear matrix inequalities (LMIs) solutions. Moreover, the underdetermined estimation problem in which the number of sensors available is typically less than the number of state variables to be estimated is specifically addressed. A systematic method is proposed to produce a model tuning parameter vector of appropriate dimension for the estimation of the filter, and the optimal transformation matrix is selected via iterative solution to minimize the estimated error. Finally, a simulation example for turbofan aeroengine is given to illustrate the effectiveness of the proposed method, and the estimated error is less than 2.5%.


Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 27 ◽  
Author(s):  
Hao Wang ◽  
Shousheng Xie ◽  
Bin Zhou ◽  
Weixuan Wang

The fault-tolerant robust non-fragile H∞ filtering problem for networked control systems with sensor failures is studied in this paper. The Takagi-Sugeno fuzzy model which can appropriate any nonlinear systems is employed. Based on the model, a filter which can maintain stability and H∞ performance level under the influence of gain perturbation of the filter and sensor failures is designed. Moreover, the gain matrix of sensor failures is converted into a dynamic interval to expand the range of allowed failures. And the sufficient condition for the existence of the desired filter is derived in terms of linear matrix inequalities (LMIs) solutions. Finally a simulation example is given to illustrate the effectiveness of the proposed method.


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