Mehatronički sustav automatkog mjenjača s dvostrukom spojkom i mehaničkim aktuatorom

U ovom radu se opisuje automatski mjenjač s dvostrukom spojkom koji ostvaruje kontinuirani prijenos snage poput planetarnog automatskog mjenjača, te istovremeno ima visok stupanj korisnosti poput ručnog mjenjača. Prvo je opisana kinematska struktura i princip rada automatskog mjenjača s dvostrukom spojkom. Zatim su detaljnije opisani elementi mjenjača relevantni za njegovu regulaciju. Neki dijelovi mjenjača su opisani pomoću dijelova konvencionalnog ručnog mjenjača te su napomenute razlike. Nakon toga se daje pregled metoda upravljanja u situacijama kod pokretanja vozila, rada o odabranom stupnju prijenosa te izmjeni stupnja prijenosa. Na kraju su opisane metode regulacije kojima postižemo željena stanja

Generalized Control Allocation Scheme for Multirotor Type of UAVs

Unmanned aerial vehicles (UAVs) are autonomous or remotely guided aircraft, which can potentially carry out a wide range of tasks. Multirotor type of UAV has unique ability to perform vertical take-off and landing (VTOL), a stationary and low-speed flight where certain configurations can achieve very complex and precise movements. Therefore, they are suitable for performing tasks such as delivery of first aid kit, firefighting, infrastructure inspection, aerial video, and many others. In this chapter, a generalized control allocation scheme for a multirotor UAV is presented, which describes the mapping of rotor angular velocities to the control vector of the aircraft. It enables control and design of multirotor configurations with diverse geometrical arrangement and characteristics of the propulsion subsystem depending on the task, which multirotor has to carry out. The inverted scheme, which is implemented as a motor mixer, maps the control inputs into a set of aircraft actuator outputs

Regulacija sile nasjedanja naftnog bušenog vretena

U ovom radu je ispitana i provedena regulacija sile nasjedanja naftnog bušnog vretena. Postavljen je odgovarajući matematički model koji u sebi sadrži elastičnosti bušnog užeta, krutost i prigušenje bušnog vretena te otpor podloge u koju bušimo. Dobiveni model je šestog reda, te ga je sa stanovišta sinteze PID regulatora potrebno pojednostaviti na model nižeg reda koji dobro opisuje dominantnu dinamiku vertikalnog pogona. Temeljem simulacijske analize ustanovljeno je postojanje longitudinalnih vibracija. U svrhu prigušenja vibracija razmatra se PID regulator. Postupak podešavanja PID regulatora sile nasjedanja zasniva se na kriteriju optimuma dvostrukog odnosa. \Navedeni regulacijski sustav je ispitan simulacijama na računalu u programskom paketu MATLAB/SIMULI\NKTM

Control Design for Unmanned Aerial Vehicles with Four Rotors

Altitude and attitude controlled quadcopter model is used for the behavior and control algorithm testing, before the implementation on the experimental setup. The main objective is the control system design which will achieve good task performance in the combination with the quadcopter dynamic model. Also, for the control model, it is important to be relatively easy to modify for the use of other control algorithms and to be easy to implement on the experimental setup. At the beginning of this article, the control system design process is described. Quadcopter dynamics equations are simplified by applying several assumptions and in that form are used for the controller synthesis. Quadcopter control system is split into inner and outer control loop because the quadcopter is underactuated system which means that the direct control of all of the degrees of freedom is not possible. In the second part, the PI-D control algorithm is described which is applied on the simplified quadcopter dynamic model. The inner loop controls roll, pitch and yaw angles together with the quadcopter altitude. Its outputs are four control variables. Outer loop controls quadcopter X and Y position. Its outputs are roll and pitch desired angles. Regulated quadcopter model behavior is shown for the three types of task. First, the achieving of position in space is simulated. Second, the reference trajectory tracking is shown. Last task shown is the reference trajectory tracking with added periodical disturbances. Simulations show bounded positions error of the regulated quadcopter system using PI-D controller for the different types of tasks performed under different conditions

Prototyping and Integration of Educational Low-Cost Mobile Robot Platform

This paper describes the process of designing and prototyping a low-cost robotic platform based on existing equipment and projects that enable extracurricular STEM activities in Croatia and beyond. A robotic platform with a differential drive configuration was chosen for education from an early age due to its simplicity and a wide range of cheap and compatible components from which it can be made. From the aspect of integration into extracurricular or curricular activities, the BBC micro:bit ecosystem was considered, enabling block-based visual programming. Components with printable parts make up the assembly of the educational robot. The main steps in designing and creating a robot prototype are presented, which consist of the modelling, 3D printing of robot parts, and assembly into a functional system. After several stages of testing, an interactive workshop was held with 7th-grade primary school pupils. Further work is planned to create educational material for extracurricular STEM workshops

THE CONCEPT OF A HYBRID ROBOTIC LAWNMOWER

U ovom radu prikazan je koncept hibridne robotske kosilice. Razmotrene su komponente sustava pri čemu je naglasak stavljen na kompatibilnost, a cilj je pravilno odabrati komponente u svrhu postizanja funkcionalnosti prototipa kosilice. Analizom troškova, utvrđeno je da je moguće izvesti prototip koji je jeftiniji od komercijalnih robotskih kosilica za primjenu košnje većih površina. Prikazan je princip rada robota s diferencijalnom konfiguracijom pogona i osnovni parametri modela. Temeljem odabranih komponenti i konfiguracije pogona, provedeno je projektiranje sustava i konstruiranje dijelova sustava. Za odabrane komponente konstruirani su ključni mehanizmi za prijenos energije koji se sastoje od remenskog prijenosa za prijenos energije na reduktor s nožem te istovremeno pokretanje generatora sustava, te lančanog prijenosa diferencijalne konfiguracije. U fazi prototipiranja kosilice, konstruirani dijelovi omogućuju izradu i sastavljanje prototipa.This paper presents the concept of a hybrid robotic lawnmower. The system components are considered with an emphasis on compatibility, and the goal is to properly select the components in order to achieve the functionality of the mower prototype. Cost analysis has shown that it is possible to design a prototype that is cheaper than commercial robotic lawnmowers for mowing larger areas. The principle of operation of differential drive configuration robots and basic model parameters are presented. Based on the selected components and drive configuration, the system design and construction of system parts were performed. For selected components, key energy transmission mechanisms have been constructed, consisting of a belt transmission for energy transmission to the reducer with a knife and the simultaneous start of the system generator, and a chain transmission of the differential configuration. In the prototyping phase of the robotic mower, the constructed parts enable the production and assembly of prototypes

Design Considerations for Autonomous Cargo Transportation Multirotor UAVs

Unmanned aerial vehicles (UAVs) have proven to be an advanced tool for a variety of applications in the civilian and military sectors. Different categories of UAVs are used in various missions and are also the subject of numerous researches. Due to their characteristics and potential in specific conditions, multirotor UAVs imposes itself as a solution for many tasks, including transport. This chapter presents a conceptual solution of autonomous cargo transportation where the primary research objective is the design of a heavy lift multirotor UAV system. The process of designing a multirotor UAV that can carry heavy lift cargo is quite challenging due to many parameters and constraints. Five selected series of electric propulsion systems are analyzed, with different multirotor configurations, and results are graphically displayed for payloads from 10 kg up to 100 kg

Mathematical Modelling of Unmanned Aerial Vehicles with Four Rotors

Mathematical model of an unmanned aerial vehicle with four propulsors (quadcopter) is indispensable in quadcopter movement simulation and later modelling of the control algorithm. Mathematical model is, at the same time, the first step in comprehending the mathematical principles and physical laws which are applied to the quadcopter system. The objective is to define the mathematical model which will describe the quadcopter behavior with satisfactory accuracy and which can be, with certain modifications, applicable for the similar configurations of multirotor aerial vehicles. At the beginning of mathematical model derivation, coordinate systems are defined and explained. By using those coordinate systems, relations between parameters defined in the earth coordinate system and in the body coordinate system are defined. Further, the quadcopter kinematic is described which enables setting those relations. Also, quadcopter dynamics is used to introduce forces and torques to the model through usage of Newton-Euler method. Final derived equation is Newton’s second law in the matrix notation. For the sake of model simplification, hybrid coordinate system is defined, and quadcopter dynamic equations derived with the respect to it. Those equations are implemented in the simulation. Results of behavior of quadcopter mathematical model are graphically shown for four cases. For each of the cases the propellers revolutions per minute (RPM) are set in a way that results in the occurrence of the controllable variables which causes one of four basic quadcopter movements in space

On-line inertia measurement of unmanned aerial vehicles using on-board sensors and a bifilar pendulum

Identification of a dynamical model and its parameters is one of the fundamental problems in the field of robotics and system dynamics modelling. For the general situation of an object motion with six degrees of freedom (6-DOF), such as in the case of the Unmanned Aerial Vehicle (UAV), the key physical parameters are vehicle mass and moment of inertia. Even though UAV mass and its geometry/topology are easily obtainable, it is difficult to identify the inertia tensor considering that it is not measurable by static tests. This article presents a simple and effective method for on-line estimation of a rigid-body inertia based on a two-wire pendulum and an on-board integrated sensor system. Herein, the test subject (i.e. UAV) is suspended by two thin parallel wires in such a way to form a bifilar torsional pendulum about the vertical axis. Using on-board sensors from the UAV flight controller (FC) unit, the pendulum oscillations are recorded and processed in order to obtain trend-free and noise-free signals used in the final inertia estimation phase. The proposed identification algorithm is verified experimentally for two typical cases of a suspended objects related to the UAV control box and a full UAV configuration

Framework for Design and Additive Manufacturing of Specialised Multirotor UAV Parts

Rapid prototyping technologies have enabled a major step forward in the development of a very wide range of products, especially in the field of mechatronic systems. These technologies are largely related to additive manufacturing (AM), so-called 3D printing which is, in addition to product development, also suitable for the fabrication of mechatronic systems that are not intended for series production. In this chapter, a framework for the AM of specialised multirotor unmanned aerial vehicles (UAVs) parts is proposed and described for three AM technologies—fused deposition modelling (FDM), selective laser sintering (SLS), and stereolithography (SLA). A different approach to parts design is shown where the main problems are addressed and guidelines for parts manufacturing are given. Special emphasis is related to the mechanical characteristics and low weight of the manufactured parts that are merged with carbon fibre segments. The manufactured (printed) parts are mounted in functional assemblies and preliminarily tested