Search

This paper revisites the direct synthesis tuning method of continuous-time low-order controllers, and specially PID controllers, for control of time-delayed single-input single-output processes. A setpoint prefilter is included to improve the servo response and integrating load disturbances are accounted for. Robustness is addressed by the feedback controller to obtain the desired maximum sensitivity value. Similar results in step disturbance compensation are obtained with simpler analytical tuning rules when compared to recently reported methods. However, the proposed procedure enables to compensate integrating load disturbances, which are not handled in the other methods.

This article presents a closed-loop position control of a mobile robot, which is capable of moving from its current position to a target point by manipulating its linear and angular velocities. The main objective of this article is to modify an existing control law based on the kinematic model to improve the response when the robot is backwards oriented and to reach the destination point in less time and with a shorter trajectory. Stability of the proposed control law is validated by Lyapunov Criterion. Some procedures are implemented to test this approach both in simulation with MATLAB, and experimentally with the Khepera IV robot.

In this work, the load disturbance rejection problem is studied. Specifically, the feedforward compensators are considered to reduce the effect of the disturbance in the process' performance. The authors propose simple tuning rules that can be easily applied to a wide range of processes improving the response against the disturbance. The improvement of the proposed method is measured through different performance indices in several simulation examples.

This work studies the control problem of an air levitation system with limited sensing capabilities. We propose a simple but considerably robust switched controller. We prove that the output of the system is globally uniformly ultimately bounded with a bound as small as we desire and we show through simulations and real experiments the robustness of the controller in the presence of disturbances, model uncertainties and parameter tuning.

In this paper, feedforward and feedback controllers are studied considering decoupled periodic event-triggering mechanisms for output and disturbance sensors. Stability and robustness conditions for linear systems are obtained considering transportation delays and actuator saturation following the Lyapunov-Krasovskii procedure. A numerical example shows that the proposed control strategy reduces the communication between sensors and controller significantly, while the system performance is not deteriorated.

Because of online laboratories (labs), students can perform experimental activities from their mobile devices and/or computers. This article proposes an experimentation environment (EE) that extends the capabilities of interactive online labs with scripting language support. Thus, control engineering students can specify complex experiments, avoid routine tasks, and empirically test controllers they made themselves.

We study the problem of periodic event-triggered targeted formation control for multi-agent Lagrangian systems. We assume that the equations of motion of each agent are derived from a Lagrangian function. Besides, each agent has information about a predefined convex set as a targeted set. The goal of the agents is to achieve the desired formation in the targeted sets, while the information is asynchronously shared by a periodic event-triggering specification, and there is also a time-delay in their communication. A novel distributed control law is proposed for the agents to reach the goal while their velocities are driven to zero. Applications and simulations are provided to validate the theoretical results.

Event-triggered control is a control strategy which allows the savings of communication resources in networked control systems. In this paper, we are interested in periodic event-triggering mechanisms in the sense that the triggering condition is only verified at predefined periodic sampling instants, which automatically ensures that Zeno behavior does not occur. We consider the case where both the output measurement and the control input are transmitted asynchronously using two independent triggering conditions. The developed result is dedicated to a class of nonlinear systems, where both the plant model and the feedback law can be described by polynomial functions. The overall problem is modeled and analyzed in the framework of time-delay systems, which allows to derive sum-of-squares (SOS) conditions to guarantee the global asymptotic stability in terms of the sampling period and the parameters of the triggering conditions. The approach is illustrated on a nonlinear numerical example.

This paper presents a library of MATLAB classes developed to provide a framework to allow performing easy and scalable process control simulations. The proposed object-oriented tool features the basic components of a control loop including: processes, controllers, sensors, actuators and connection links. The simulator can be configured to carry out simulations with continuous and/or discrete elements, and/or include event-triggered capabilities in a straightforward manner. The benefits of the proposed library are shown with the rapid development and simulation of a quadruple-tank system that is controlled by means of a PI controller.

In this paper, periodic event-triggered controllers are proposed for the rotary inverted pendulum. The control strategy is divided in two steps: swing-up and stabilization. In both cases, the system is sampled periodically but the control actions are only computed at certain instances of time (based on events), which are a subset of the sampling times. For the stabilization control, the asymptotic stability is guaranteed applying the Lyapunov–Razumikhin theorem for systems with delays. This result is applicable to general linear systems and not only to the inverted pendulum. For the swing-up control, a trigger function is provided from the derivative of the Lyapunov function for the swing-up control law. Experimental results show a significant improvement with respect to periodic control in the number of control actions.