A Multilevel Inverter Bridge Control Structure with Energy Storage Using Model Predictive Control for Flat Systems

The paper presents a novel technique to control the current of an electromagnetic linear actuator fed by a multilevel IGBT voltage inverter with dynamic energy storage. The technique uses a “cascade model predictive control (MPC),” which consists of two MPCs. A predictive control of the trajectory position predicts the optimal current, which is considered to be the desired current for the second MPC controller in which a hysteresis control technique is also integrated. Energy is stored in a capacitor using energy recovery. The current MPC can handle a capacitor voltage higher than the source voltage to guarantee high dynamic current and disturbance compensation. The main contribution of this paper is the design of an optimal control structure that guarantees a capacitor recharge. In this context, the approach is quite new and can represent a general emerging approach allowing to reduce the complexity of the new generation of inverters and, in the meantime, to guarantee precision and acceptable switching frequency. The proposed technique shows very promising results through simulations with real actuator data in an innovative transportation technology

An introductional lecture on chaotic systems through Lorenz attractor and forced Lotka Volterra equation for interdisciplinary education

Is it possible to predict the future? How accurate is the prediction for the future? These questions are fascinating and intriguing ones in particular for young generations who look at their future with curiosity. For a long time, many have tried to quantitatively predict future behavior of systems more accurately with techniques such as time series analysis and derived dynamical models based on observed data. The paper proposes a lecture structure in which elements of chaos, which greatly impacts the predictive capabilities of dynamical models, are introduced through two classical examples of nonlinear dynamical systems, namely Lorenz attractor and Lotka-Volterra equations. In a possible lecture, these two structures are introduced in a basic and intuitive way, followed by equilibria analyses and Lyapunov control approaches. The paper intends to give a possible structure of an interdisciplinary lecture in chaotic systems, for all students in general and non-engineering students in particular, to kindle students’ interest in challenging ideas and models. By presenting an intuitive learning-based approach and the results of the implementation, the paper contributes to the discourse on interdisciplinary education. The lecture is a part of a course within a Complementary Study at Leuphana Unversity of Lüneburg. The material which inspired the proposed lecture structure is taken from the scripts of the Master Complementary Course titled Modelling and Control of Dynamical Systems using Linear and Nonlinear Differential Equations held at Leuphana University of Lüneburg

An introduction to sliding mode control for interdisciplinary education

This paper proposes a new lecture structure for an introduction to Sliding Mode Control (SMC) for a wider audience of undergraduate students. In particular, the intuitive derivation of the sliding variable and choice of the sliding surface is emphasized in order to obtain an intuitive understanding in a gradual manner. The structure of the lecture is conceived in an inclusive way, considering only the common mathematical high school background and basic knowledge about simple differential equations and their solutions. In this sense, SMC can represent a possible application of the already acquired knowledge and in the meantime provide contact with one of the most important control techniques in theory and application. The paper intends to give a possible structure of an interdisciplinary lecture in SMC for teachers and students (in particular, non-technical students). By presenting the research-based approach and the results of the implementation, the paper contributes to the discourse on interdisciplinary education in engineering. Engineering students’ courses of action have been videorecorded in design projects and in electronics labs at two universities. It can bee seen that students’ use a wealth of bodily-material resources that are an integral and seamless part of students’ interactions. They use bodily resources, concrete materials, “low-tech” inscriptions as well as “high-tech” (“digital”) inscription devices. Our results challenge that by hand – by computer and analogue tools – digital tools should be seen as dichotomies. Our empirical evidence suggests that students should be trained to not only be trained to work with “digital” tools but with a multitude of tools and resources. We, thus, advocate that a postdigital perspective should be taken in education where the digital makes up part of an integrated totality

Cascade MIMO P-PID controllers applied in an over-actuated quadrotor Tilt-Rotor

To map the Virtual Control Actions (VCAs) into Real Control Actions (RCAs), over-actuated systems typically require nonlinear control allocation methods. On embedded robotic platforms, computational efforts are not always available. With this in mind, this work presents the design of a Quadrotor Tilt-Rotor (QTR) through a new concept of control allocation with uncoupled RCAs, where a nonlinear system is divided into partially dependent and linear subsystems with fast and robust convergence. The RCAs are divided into smaller and linearized sets and solved sequentially. Then, the cascade Multipe-Input-Multipe-Output (MIMO) Proportional (P)- Proportional, Integral and Derivative (PID) controllers tuning were presented with saturation constants and successive loop closure technique, where some open-field environment tests were conducted to validate the respective tuning. In the end, it showed to be reliable, robust, efficient, and applicable when VCAs are overlapped between the subsystems.The authors would like to thank CEFET-MG and Leuphana University of L¨uneburg for their financial support.info:eu-repo/semantics/publishedVersio

Robust decoupling through algebraic output feedback in manipulation systems

summary:This paper investigates the geometric and structural characteristics involved in the control of general mechanisms and manipulation systems. These systems consist of multiple cooperating linkages that interact with a reference member of the mechanism (the “object”) by means of contacts on any available part of their links. Grasp and manipulation of an object by the human hand is taken as a paradigmatic example for this class of manipulators. Special attention is devoted to the output specification and its controllability. An example design of a force controller using algebraic output feedback is presented at the end of this paper. In this example, a matrix representing a static output feedback is designed. The coefficients of this matrix are the weights for the sensed outputs. With the approach proposed in this paper, a robust decoupling is obtained between the output feedback and the contact forces and joint positions