Pepper to fall: a perception method for sweet pepper robotic harvesting

Intelligent Service Robotics - In this paper we propose a robotic system for picking peppers in a structured robotic greenhouse environment. A commercially available robotic manipulator is equipped...     

Visual Target Localization with the Spincopter

The goal of the Spincopter project was to design an energy efficient aircraft capable of autorotation glide that could be used for both indoor and outdoor surveillance. This paper demonstrates how to utilize the self-rotating capability of the Spincopter in order to acquire a 3D image of its environment and localize predefined object(s). The omnidirectional capabilities of such an UAV extends the otherwise very limited field of view of conventional cameras usually used for aerial photography and surveillance. The paper presents the theoretical background and the actual implementation of such a system. It presents the resulting images and offers a brief survey of the image quality.     

Model-Reference Fuzzy Adaptive Control as a Framework for Nonlinear System Control

The paper presents a general methodology of adaptive control based on fuzzy model to deal with unknown plants. The problem of parameter estimation is solved using a direct approach, i.e. the controller parameters are adapted without explicitly estimating plant parameters. Thus, very simple adaptive and control laws are obtained using Lyapunov stability criterion. The generality of the approach is substantiated by Stone-Weierstrass theorem, which indicates that any continuous function can be approximated by fuzzy basis function expansion. In the sense of adaptive control, this implies the adaptive law with fuzzified adaptive control parameters. The proposed control algorithm may be viewed as an extension of classical adaptive control for linear plants, but compared to the latter it provides higher adaptation ability and consequently better performance if the plant is nonlinear. The global stability of the control system is assured and the tracking error converges to the residual set that depends on fuzzification properties. The main advantage of the approach is simplicity that suits control engineers since wide range of industrial processes can be controlled by the proposed method. In the paper, the control of heat exchanger is performed.     

Hybrid Adaptive Control for Aerial Manipulation

This paper presents a control scheme to achieve dynamic stability in a mobile manipulating unmanned aerial vehicle (MM-UAV) using a combination of Gain scheduling and Lyapunov based model reference adaptive control (MRAC). Our test flight results indicate that we can accurately model and control our aerial vehicle when both moving the manipulators and interacting with target objects. Using the Lyapunov stability theory, the controller is proven to be stable. The simulation results showed how the MRAC is capable of stabilizing the oscillations produced from the unstable PI-D attitude control loop. Finally a high level control system based on a switching automaton is proposed in order to ensure the saftey of the aerial manipulation missions.     

Educational aspects of CAD supported real time control

Educational aspects of CAD supported real time control are discussed. The historical development of the equipment and appropriate software concerning laboratory exercises in the field of real-time control is briefly described. The hardware and software equipment used in the education process at Ljubljana University is briefly described. Emphasis is given to the equipment developed: a hydraulic-thermal pilot plant, two CACSD program packages with their real-time capabilities, and a special program for real time control in addition to emphasizing their connection in a powerful educational system. Some typical exercises from undergraduate courses, e.g., some experiments on the connection of analog and digital computer, identification of the hydraulic process and its level control, as well as some exercises from a graduate course, e.g., the implementation of adaptive digital filtering in real-time are described. Some difficulties encountered when applying the theory to practical problems are discussed     

Catalytic pyrolysis and kinetic study of real-world waste plastics: multi-layered and mixed resin types of plastics

Clean Technologies and Environmental Policy - Multi-layered and mixed resin types of plastics are a great challenge for the waste recycling industry. The majority consist of two or more types of...     

CSBD Healing in Rats after Application of Bovine Xenogeneic Biomaterial Enriched with Magnesium Alloy

Xenogeneic biomaterials Cerbone^® and OsteoBiol^® are widely used in oral implantology. In dental practice, xenogeneic biomaterial is usually combined with autologous bone to provide bone volume stability needed for long-term dental implants. Magnesium alloy implants dissolve and form mineral corrosion layer that is directly in contact with bone tissue, allowing deposition of the newly formed bone. CSBD heals by intramembranous ossification and therefore is a convenient model for analyses of ostoconductive and osteoinductive properties of different type of biomaterials. Magnesium alloy-enriched biomaterials have not yet been applied in oral implantology. Therefore, the aim of the current study was to investigate biological properties of potentially new bovine xenogeneic biomaterial enriched with magnesium alloy in a 5 mm CSBD model. Osteoconductive properties of Cerabone^®, Cerabone^® + Al. bone, and OsteoBiol^® were also analyzed. Dynamics of bone healing was followed up on the days 3, 7, 15, 21, and 30. Calvary bone samples were analyzed by micro-CT, and values of the bone morphometric parameters were assessed. Bone samples were further processed for histological and immunohistochemical analyses. Histological observation revealed CSBD closure at day 30 of the given xenogeneic biomaterial groups, with the exception of the control group. TNF-α showed high intensity of expression at the sites of MSC clusters that underwent ossification. Osx was expressed in pre-osteoblasts, which were differentiated into mature osteoblasts and osteocytes. Results of the micro-CT analyses showed linear increase in bone volume of all xenogeneic biomaterial groups and also in the control. The highest average values of bone volume were found for the Cerabone^® + Mg group. In addition, less residual biomaterial was estimated in the Cerabone^® + Mg group than in the Cerabone^® group, indicating its better biodegradation during CSBD healing. Overall, the magnesium alloy xenogeneic biomaterial demonstrated key properties of osteoinduction and biodegradidibility during CSBD healing, which is the reason why it should be recommended for application in clinical practice of oral implantology.     

Representation of journals from five neighboring European countries in the Journal Citation Reports

This study explores the representation of scientific journals from Italy, Hungary, Slovenia, Croatia, and Serbia and Montenegro in the Thomson Scientific’s 2005 Journal Citation Reports (JCR). The number of journals covered by JCR was analyzed in relation to scientific productivity of selected countries and the size of their economies, and no apparent relationship between these factors was found. Our findings suggest that other factors, including the quality of individual journals, may influence how many journals a country will have in the JCR.     

Two Degrees of Freedom in the Control of a DC-DC Boost Converter,Fuzzy Identified Explicit Model in Feed-forward Line

We present a novel approach to the fuzzy control of a DC-DC Boost Converter. Using heuristic partitioning of the main control parameters and focusing on global knowledge of the open-loop, stable system’s equilibriums, the new method is developed based on an offline fuzzy identification of the steadystate duty cycle. The explicit and the fuzzy identified global model of the duty cycle robustly contribute to the system’s stability, even in the presence of large changes to the process parameters. In comparison with the analytically derived duty cycle using two different methods, the identified model prediction of an infinity horizon duty cycle shows better precision. These results are achieved in an analysis of the converter’s hybrid-simulation model where the assumptions made in the mathematical modelling are minor in comparison with similar assumptions in physical examples. The steady-state error compensation relies on the optimized PI controller, which is independently constructed and involved in the final Two-Degreesof-Freedom (TDOF) controller. The successful simulation results agree with the robustness and present a DC-DC converter with stable operation, even in the dynamic exchange of the DCM (Discontinuous Conduction Mode) and CCM (Continuous Conduction Mode). The method is widely applicable as it minimizes the real time of processing and avoids over-determined solutions.     

Modeling and Control of MM-UAV: Mobile Manipulating Unmanned Aerial Vehicle

Compared to autonomous ground vehicles, UAVs (unmanned aerial vehicles) have significant mobility advantages and the potential to operate in otherwise unreachable locations. Micro UAVs still suffer from one major drawback: they do not have the necessary payload capabilities to support high performance arms. This paper, however, investigates the key challenges in controlling a mobile manipulating UAV using a commercially available aircraft and a light-weight prototype 3-arm manipulator. Because of the overall instability of rotorcraft, we use a motion capture system to build an efficient autopilot. Our results indicate that we can accurately model and control our prototype system given significant disturbances when both moving the manipulators and interacting with the ground.