Claudiu Pozna

Generic two-degree-of-freedom linear and fuzzy controllers for integral processes

Abstract This paper presents a new framework for the design of generic two-degree-of-freedom (2-DOF), linear and fuzzy, controllers dedicated to a class of integral processes specific to servo systems. The first part of the paper presents four 2-DOF linear PI controller structures that are designed using the Extended Symmetrical Optimum method to ensure the desired overshoot and settling time. The second part of the paper presents an original design method for 2-DOF Takagi–Sugeno PI-fuzzy controllers based on the stability analysis theorem. Experimental results for the speed control of a servo system with variable load illustrate the performance of the new generic control structures.

Signatures: Definitions, operators and applications to fuzzy modelling

This paper presents a new framework for the symbolic representation of data which is referred to as signatures. The definitions of signatures and of signature trees are first given. Original operators on signatures are next presented, i.e., contraction, extension, pruning, addition, multiplication, and grafting. Attractive applications of signatures related to the modelling of fuzzy inference systems are suggested and discussed. An example is included to accompany the theoretical results.

A novel pose estimation algorithm for robotic navigation

This paper proposes a new pose estimation algorithm in the framework of robotic navigation problems. The algorithm gives the mobile robot (MR) pose on the basis of the difference between the MR desired pose and the MR current pose. In this regard the MR sensor readings and the readings of a virtual sensor are employed. The algorithm is advantageous in comparison with other pose estimation algorithms including those based on classical filter approaches because of the small computation time. Simulation and real-world experimental results are included to illustrate the effectiveness of the pose estimation algorithm and its potential for integration in MR control structures and algorithms. A new pose estimation algorithm is proposed.The difference between the mobile robot desired and current pose is computed.The mobile robot sensor readings and the virtual sensor readings are employed.The algorithm is tested by simulation and real-world experimental results.

Short communication: New results in modelling derived from Bayesian filtering

This paper suggests an original heuristic modelling algorithm expressed in terms of homogenous combinations of the classical system dynamics and the Bayesian degree of truth employed in modelling. The main benefits of the proposed approach compared to classical modelling are the increased transparency and alleviated computational time. Two case studies, dealing with a mobile robot and an unforced pendulum system, are included to exemplify and test the theoretical results. One of the case studies makes use of the definition and calculation of several discrete plausibilities.

Modular Robots Design Concepts and Research Directions

The paper intends to develop a conceptual foundation for our next works in industrial robots modular design. The goal of this works is to develop cheap and improved robots which are adapted to the costumer needs.

Characteristics of a new abstraction model

The paper presents research results concerning cognition aspects with focus on causality. An abstraction model is proposed. It represents one of the basic processes of learning and cognition. The definitions of classes and subclasses stand for the definition of the new model of abstraction. The following characteristics are used to describe the new abstraction model: knowledge energy, Shannon entropy, and knowledge temperature. They aim the better knowledge manipulation. Two case studies exemplify the application of the abstraction model.

Stability analysis and design of a class of MIMO fuzzy control systems

This paper presents a new stability analysis method dedicated to a class of fuzzy control systems FCSs controlling multi input-multi output MIMO nonlinear processes by means of Takagi-Sugeno-Kang fuzzy logic controllers FLCs. The stability analysis of the FCSs is carried out using LaSalles global invariant set theorem by the separate stability analysis of each fuzzy rule in MIMO fuzzy control systems. Therefore the complexity of the stability analysis is reduced and the adding of new fuzzy rules can be conducted easily; this modification of FLC structure requires the fulfillment of only one of the conditions of the stability analysis theorem suggested in this paper. Another advantage of the stability analysis approach proposed in this paper is that the derivative of the Lyapunov function candidate must be only negative semi-definite in comparison with Lyapunovs stability theorem where it must be negative definite. The conservativeness of stability conditions is thus reduced, and this enables the convenient design of FLCs. The applicability and efficiency of the theoretical results are illustrated by numerical simulations for a representative MIMO process which deals with the level control in a three spherical tank system.

Cooperation in multiagent systems

This paper gives aspects related to a cooperation scenario in the framework of multiagent systems. The presentation is focused on a multiagent system that consists of two agents, the Master and the Apprentice. The theoretical basis of the cooperation scenario is the definition of the most probable process, and two algorithms are used with this regard. The formulation of the cooperation scenario is exemplified for a case study that builds an architecture of successively placed bricks in the workspace.

Takagi-Sugeno fuzzy controller for a magnetic levitation system laboratory equipment

This paper presents the design and the implementation of two control solutions applied to a magnetic levitation system laboratory equipment. The first solution deals with a state feedback control structure to stabilize the controlled plant which is the inner control loop for the cascade control system structure proposed as the second solution. The second solution is based on a Takagi-Sugeno fuzzy controller in the outer control loop to ensure the zero steady-state control errors. Simulation and real time experimental results are included to illustrate the performance of the control systems and to validate the two control solutions in regulation and tracking.

Issues about autonomous cars

The Autonomous car is a complex topic, different technical fields like: Automotive engineering, Control engineering, Informatics, Artificial Intelligence etc. are involved in solving the human driver replacement with an artificial (agent) driver. The problem is even more complicated because usually, nowadays, having and driving a car defines our lifestyle. This means that the mentioned (major) transformation is also a cultural issue. The paper will start with the mentioned cultural aspects related to a self-driving car and will continue with the big picture of the system.