Transactions of the Institute of Measurement and Control

Du, Shengli; Yan, Qiushuo; Qiao, Junfei

doi: 10.1177/01423312221114704pmid: N/A

The secure consensus problem of multiagent systems with fixed topology and external disturbances is investigated in this paper. Along with external disturbances, the studied multiagent system is also subjected to denial-of-service (DoS) attacks. First, some graph-based Lyapunov functions are presented for the robust consensus analysis. Second, the duration and attack frequency are introduced to quantitatively analyze the DoS attacks’ effects on the consensus. Third, the gain of the controller is acquired by solving an algebraic Riccati equation (ARE), which can always be guaranteed compared with solving linear matrix inequalities (LMIs). Finally, a numerical simulation of a microgrid test system is provided to demonstrate the effectiveness of the proposed strategy.

Iqbal, Maryam; Imtiaz, Junaid; Mahmood, Asif

doi: 10.1177/01423312221111643pmid: N/A

The movement coordination of the robotic digit(s) with the central nervous system (CNS) and the natural digit(s) is a complex task that needs to be executed successfully in an anthropomorphic hand. The task is challenging to resolve because of the CNS. We developed a theoretical framework for the biomechanical model of a partially impaired human hand utilizing the bond graph modeling technique by incorporating inertia, muscle, and visco-elastic dynamics. The research presents a partially impaired human hand model with a robotic digit and four natural digits having 21 degrees of freedom. We formulated a linear quadratic Gaussian (LQG) integral control technique for the 21st-order model to regulate the flexion and extension movement of the robotic digit while considering the disturbances. We have simulated the modeling scheme in MATLAB/Simulink. The flexion and extension movement and the angular velocity of the robotic finger are shown to be following all the physiological constraints of a natural finger. The settling time is achieved at 1.6 seconds, with a maximum flexion angle of 0.135 rad. The sensitivity analysis shows that the model is robust against disturbances. The simulation results exhibit the application of this scheme toward upper limb rehabilitation and improvement in prosthetic and exoskeleton designs.

Jiao, Chenxu; Zhang, Junfeng; Jia, Xianglei; Zhang, Suhuan

doi: 10.1177/01423312221107980pmid: N/A

This paper is concerned with the event-triggered control of positive switched systems with randomly occurring state saturation. First, a vector-based event-triggering condition is established. Thus, interval and polytope approaches are used to deal with the positivity and stability of the systems and the saturation, respectively. An event-triggered controller and the corresponding domain of attraction are designed by decomposing gain matrix into the sum of non-negative and non-positive components. The proposed design approach is developed for the systems with input saturation. Finally, two examples are given to illustrate the effectiveness of the proposed design.

Duman Mammadov, Ayşe; Dincel, Emre; Söylemez, Mehmet Turan

doi: 10.1177/01423312221110702pmid: N/A

In this paper, a decentralized proportional–integral proportional–retarded (PI-PR) controller design method is proposed for two-input two-output (TITO) systems in discrete-time domain. The well-known dominant pole assignment (DPA) approach is used as the basis of the proposed approach. The controller design starts with the decoupling of a given TITO system into two sub-systems and continues with the design of proportional–integral–retarded (PIR) controllers for each sub-system, respectively. The feasible discrete PIR controller parameter set is obtained through the Nyquist stability criterion by considering the desired closed-loop performance specifications. The obtained PIR controllers are then implemented using a PI-PR control structure to avoid poor performance of the closed-loop system (CLS) transient response, which can be caused by the controller zeros. Moreover, a case study is presented to show the performance of the PI-PR controller in a simulation environment. It is shown that the proposed control structure provides a satisfactory performance when compared with the other proportional–integral–derivative (PID) control methods from the literature.

Lin, Bing; Ren, Junchao

doi: 10.1177/01423312221112213pmid: N/A

This paper addresses the problem of preview sliding mode control for a class of nonlinear uncertain discrete-time singular systems with time-delays. A difference operator approach is used to deal with the controlled system such that the derived augmented systems including preview information of reference signal can be constructed. A suitable surface is proposed in the sense of admissibility by the free-weighed matrix technique. Based on this, a sliding mode controller with preview information is constructed incorporating with the tracking error to ensure that the closed-loop control system reaches the designed sliding mode surface within finite time. To apply the proposed control scheme to the practical engineering systems, the sliding mode tracking controller with preview information is developed for a DC motor based on the proposed control approach. The comparative experiment results demonstrate that the preview information of reference signal can improve the tracking performance.

Xin, Jinghao; Yu, Liying; Wang, Junda; Li, Ning

doi: 10.1177/01423312221110999pmid: N/A

The economic dispatch (ED) problem aims to minimize the total generation cost while satisfying certain constraints, such as valve-point effects, multi-fuel options, prohibited operating zones, transmission losses, and ramp rate limits. In this paper, these constraints are considered simultaneously for the first time, resulting in a complex nonconvex ED problem. A diversity-based parallel particle swarm optimization (DPPSO) is proposed to solve the nonconvex ED problem, where the implementation details—such as evaluation function design, particle definition, and equality and inequality handling strategies—have been carefully discussed. In our approach, the population of DPPSO is divided into different groups to maintain diversity in particles so that the optimization capacity can be enhanced. An asynchronous information–sharing mechanism (AISM) helps decrease the population size. Hence, the computational burden is reduced. Moreover, information in different groups is calculated parallelly and updated asynchronously to improve computational efficiency. Benchmark functions are employed to demonstrate the effectiveness of the proposed method. Furthermore, three nonconvex ED problems are resolved by the proposed method, and state-of-the-art performance has been achieved. In addition, the proposed algorithm is highly modular, making it easy to unite other salient variants of particle swarm optimization (PSO) to improve its performance.

Zhu, Xinye; An, Tianjiao; Wang, Gang

doi: 10.1177/01423312221109726pmid: N/A

In this paper, the position–force–based approximate optimal control method is developed for reconfigurable robots using zero-sum game strategy. By utilizing the Newton–Euler iteration technique, the robotic system’s dynamic model is formulated and the state space equation is derived. According to adaptive dynamic programming (ADP) and neural network algorithm, the trajectory tracking control problem is transformed into a zero-sum game-based optimal control issue. The optimal control policy and worst disturbance policy are obtained by Hamilton–Jacobi–Issacs (HJI) function, respectively. Unlike the conventional learning–based robotic control method, the proposed zero-sum game-based method no need extra sub-controller that can reduce the computational burden. The reconfigurable robot system’s tracking error is uniformly ultimately bounded by the Lyapunov theorem. Finally, simulation experiments demonstrate the advantages of the proposed method.

Arbabi Yazdi, Yaser; Toossian Shandiz, Heydar; Gholizade Narm, Hossein

doi: 10.1177/01423312221118129pmid: N/A

This study detects oscillations in the control loop and separates them from others by implementing supervised machine learning on generalized and normalized statistical variables. Oscillations in the control loops can result in high variability of performance, increase the costs, increment defects and potential hazards in the future. Valve stiction is one of the most important reasons for oscillatory behaviour in the process industry. The detection of this non-linear parameter becomes even more complex in the presence of other oscillating factors, such as poor controller tuning and external disturbances. The proposed method is based on a six-step algorithm. After preparing the data, the best classifier is selected from three trained classifiers Naïve Bayes, support vector machine and K-nearest neighbours’ separators. Finally, the decision tree will automatically detect and classify oscillating factors in the control loop. This method is independent of the process model, and through the decision tree, it determines the probability of occurrence of each oscillation factor in the loop. The resulting system was tested on benchmark industrial data to illustrate the effectiveness of the proposed method.

Li, Chen; Xia, Hong; Zhu, Hongtao

doi: 10.1177/01423312221117083pmid: N/A

This paper investigates the bipartite containment control problem for second-order multi-agent systems (MASs) via asynchronous sampling under switching topologies, where the relationships of both competition and cooperation exist among agents. Under asynchronous setting, each agent only receives its neighbors’ information at its own clock which is independent of the others’. The objective of bipartite containment control is to make the followers converge to a convex hull containing each leader’s trajectory as well as its opposite trajectory, which is the same as it in modulus but different in sign. First, the bipartite control problem is transformed into the converge problem of the product of infinite time-varying row stochastic matrices. Then, based on the theoretical tools including graph theory, nonnegative matrix theorem, and composition of binary relation, a sufficient condition is obtained for the bipartite containment control problem. It is shown that with proper parameters, the bipartite containment control can be achieved if the union of topology graphs related to any time intervals with given length has a directed spanning forest. Finally, the validity of the theoretical result under asynchronous sampling is demonstrated by a numerical simulation.

Yang, Ran; Liu, Song; Li, Xiaoyan; Huang, Tao

doi: 10.1177/01423312221116713pmid: N/A

This paper discusses stability of delayed fractional-order switched systems. First, two useful propositions are proposed based on Razumikhin approach together with properties of fractional calculus and analytical techniques, which can well solve the difficulties caused by distributed and discrete delays and fractional-order derivatives. Then, with the help of multiple Lyapunov function approach and dwell time technique, an effective way is developed to overcome the trouble caused by switching rules. A delay-dependent dwell time is derived to guarantee asymptotic stability under the hypothesis that each subsystem of delayed fractional-order switched systems is asymptotically stable. Finally, two illustrative examples further clarify the obtained conclusions.