Research Interests

control theory, IoT, fluid power

Degrees

• PhD in control theory and mechanical engineering, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, 2022
• MS in control theory and mechanical engineering, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, 2017
• BS in control theory and mechanical engineering, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, 2015

Publications

1. J. Karlušić, M. Cipek, D. Pavković, Š. Željko, J. Benić, M. Šušnjar, Benefit Assessment of Skidder Power-train Hybridization utilizing a novel Cascade Optimization Algorithm, Sustainability 12 (2020)
   Abstract

   Over the last decade, off-road vehicles are being increasingly hybridized through power-train electrification in terms of additional electrical machine-based propulsion and battery energy storage, with the goal of achieving significant gains in fuel economy and reductions in greenhouse gases emissions. Since hybrid power-trains consist of two or more different energy sources and may be arranged in many different configurations, there are many open questions in their design and powertrain energy management control, which may have influence on the hybridized power-train purchase cost and efficiency. The paper presents a simple backward optimization models of conventional and hybrid cable skidder powertrain. The models are then used in control variables optimization over one forest path in order to find the minimum possible fuel consumption. The optimization results show that 15% fuel efficiency improvement in winching and skid trail driving can be achieved with the selected hybrid powertrain. With that improvement, main hybrid drive components can be paid off in 13 years and if achieved efficiency improvement can be carried throughout all skidder’s operations pay off time is reduced to 44 months.
2. J. Karlušić, M. Cipek, D. Pavković, J. Benić, Š. Željko, Z. Pandur, M. Šušnjar, Simulation Models of Skidder Conventional and Hybrid Drive, Forests 11/9 (2020)
   Abstract

   The paper presents a hypothetical conversion of a conventional cable skidder powertrain to its hybrid version. Simulations of skidder operation were made for two existing forest paths, based on the technical characteristics of the engine, transmission system and the characteristics of the winch. Fuel and time consumption were calculated per working cycle considering the operating conditions (slope, load mass). The model was then converted to a hybrid version by adding a battery energy storage system in parallel with the electrical power generator and by employing an energy management control strategy. The dimensions of the battery and the power generator were chosen based on the characteristics of the existing winch with the aim of completely taking over its operation. The management strategy was selected using the specific fuel consumption map. All simulations were repeated for the hybrid drive under the same operating conditions. The results show that fuel savings of around 13% can be achieved with the selected hybrid drive and steering strategy.
3. M. Orešković, J. Benić, M. Essert, A Step toward Machine Recognition of Complex Sentences, TEM Journal 7 (2018), 823-828
   Abstract

   This paper presents theoretical and technological background of a model for machine recognition of complex sentences. It is based on the Syntactic and Semantic Framework (SSF) which implements fundamental linguistic fields network resources and encyclopedias. It can be used to extract subject, predicate and object, as well as other sentence's parts (e.g. NP/VP/PP), and in some cases even semantic roles. In compound sentences the machine can easily recognize independent sentences, whereas in complex sentences the machine recognizes the main clause and the related subordinate clauses as well as sentence types (subject, object, predicate, etc.). Using stored patterns various theories can be tested.

1. D. Pavković, M. Cipek, Š. Željko, J. Benić, M. Šušnjar, Hybrid Power-trains for Sustainable Forestry - A Review, 4th South East Europe Conference on Sustainable Development of Energy, Water and Environment Systems, Sarajevo, Bosna i Hercegovina, 2020
   Abstract

   Nowadays there are increasing demands in terms of reducing the cost of running forestry machines along with the regulatory pressures for lower exhaust emissions to improve the ecological indices and reduction of acoustic noise in order to better comply with industry ergonomic guidelines. Therefore, the producers of forestry equipment are increasingly interested in electrification of heavy machinery, which can already be seen as appearance of the certain hybrid and electric forestry vehicles. The hybrid power-train apparently offers a favourable solution that can meet the above requirements for the propulsion of articulated forestry tractors, also known as skidders, due to the possibility of using a lower-power diesel engine, along with an additional energy storage system (e.g. battery) and driveline power source (i.e. electric motor). This allows the considered hybrid power-train configuration to operate with higher overall energy efficiency and higher mechanical performance indices over the conventional (diesel engine-based) propulsion system, and notably extended autonomy compared to fully-electrified power-trains. Moreover, hybrid power-train requires a smaller battery with less energy then its purely electric counterpart, which results in lower power-train weight and total installation cost. The precise determination of the energy consumption of different types of forest vehicles working in different operating regimes and under different terrain conditions is necessary to select the proper power-train for a specific application. The future development of electrified forestry vehicles is also a very important research topic in the field of sustainable forestry engineering. Having this in mind, this paper presents a literature review on existing solutions for hybrid forestry vehicle propulsion.
2. J. Karlušić, M. Cipek, D. Pavković, Š. Željko, J. Benić, M. Šušnjar, Benefit Assessment of Skidder Power-train Hybridization, 4th South East Europe Conference on Sustainable Development of Energy, Water and Environment Systems, Sarajevo, Bosna i Hercegovina, 2020
   Abstract

   This paper presents a hypothetical conversion of a conventional articulated forestry tractor known as skidder to its hybrid counterpart by incorporating a battery energy storage system. Starting from the basic parameters of 84 kW diesel-powered skidder currently found in the national forestry company fleet, the quasi-static model of the skidder is derived and validated. The conventional skidder model is then converted to its hybrid counterpart by adding a battery energy storage system in parallel with the electrical power generator and an adequate energy management control strategy. The hybrid skidder power-train components are also appropriately re-sized in order to meet comparable traction force and power performance. Both the conventional and hybridized skidder models are then used for the purpose of comparative analysis of main vehicle characteristics for the off-road driving scenario, which includes realistic slope and terrain limitations. The obtained simulation results are used to gain insights about the possible advantages of the proposed conversion/drive-train hybridization in terms of feasible reduction of fuel consumption and related CO 2 emissions, while also considering additional hybridization costs and return of investment period.

3. J. Benić, Š. Željko, Position Controller for Direct Driven Electro- Hydraulic System, International Conference Fluid Power 2019, Maribor, Slovenija, 2019, 181-193
   Abstract

   In the past few years, decentralized hydraulics gain advantage over classical hydraulics due to lower energy consumption, lower pressure losses in pipelines and easy automatization. In this paper, Direct Driven Electro-Hydraulic (DDEH) drive is made in parallel with a classical proportional hydraulic system. In DDEH control method the valve is replaced with reversible pumps/motors which are directly controlled with a servo motor. Such systems combine best properties of both hydraulic and electric drives. Proposed experimental setup is designed for easy switching between both systems which allows exact comparison of obtained experimental results. The nonlinear models of both systems have been derived using PID controller and simulated in Matlab program. Finally, the conclusion regarding precise position control and system dynamics is given in detail.
4. Š. Željko, D. Žgela, J. Benić, Wireless Control of an Electro-Hydraulic Robotic Manipulator, 11th International Fluid Power Conference, Aachen, Njemačka, 2018, 387-395
   Abstract

   This paper deals with the design, practical realization and wireless control of a prototype of an electro-hydraulic robotic manipulator (EHROM) suitable for handling heavy weight objects in industrial environment. The EHROM has been designed in the Laboratory for Automation and Robotics at the Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb. The prototype has been completely built in cooperation with two Croatian companies and is fully open to implementations of various control methods. The robotic manipulator has three-degrees-of- freedom (spherical or polar kinematic configuration) with a hydraulic gripper at the end of the mechanical structure. The manipulator uses a load sensing hydraulic system that provides superior controllability regardless of the load and also contributes to the energy efficiency. Originally the manipulator had no advanced way of being operated, other than the use of joystick or levers on the hydraulic valve block itself. The control system has been upgraded with an assembly suitable for wireless control of the manipulator using a mobile device on iOS platform. This multidisciplinary task involved skills in mechanical engineering, electronics and electrics, as well as computing. The paper focuses on the wireless control of the manipulator using a low-cost microcontroller and custom made controlling interface.
5. T. Žilić, M. Essert, J. Benić, I. Kuzmanović Ivičić, Universal M-Valued logic, 6th World Congress and School on Universal Logic, Vichy, Francuska, 2018, 485-489
   Abstract

   This paper based on M-theory wants to show the correlation of Cartesian product of elements of ordered set with a basic, multi-value logic. Using simple algorithms discovered by M. Sare in the natural laws of electrical networks, it is possible to construct logical tables, i.e. grids, for all logic functions of n variables.
6. J. Benić, N. Rajčić, Š. Željko, Precise force control for hydraulic and pneumatic press system, International Conference Fluid Power 2017, Maribor, Slovenija, 2017, 57-71
   Abstract

   This paper presents the force control methods for a pneumatic and a hydraulic press. Both systems have been made for educational purposes as well as for experimental testing and verification of different control techniques. The pneumatic press contains a proportional pressure valve which is used for pressure regulation in a cylinder chamber and has direct impact on controlled force. The proportional pressure regulator also allows an indirect calculation of the cylinder force by measuring the control pressure at the valve outlet, which is less precise than direct measurement of pressing force by using a force transducer. Arduino board was used as a controller for the pneumatic press and it can be programmed via Arduino hardware support for Matlab/Simulink program or via Arduino open-source platform. The control algorithm is implemented in the Matlab/Simulink environment, which allows executing the simulation program in external mode, similar to the Real-Time Workshop tool. The hydraulic press contains a servo-solenoid pressure-control valve for regulating the cylinder pressure. The pressing force can also be indirectly measured by a pressure transducer which is installed in the cylinder chamber. Similar to the case of the pneumatic press, more precise measurement of the pressing force can be achieved with a force transducer. The control algorithm has been implemented on a real-time hardware board by using the Real-Time Workshop tool for generating the C code and building an executive program. Experimental tests have shown that electrically actuated control components supported by the appropriate measuring devices and computer programs make it possible to improve the characteristics of the hydraulic and pneumatic systems required in modern industrial plants.
7. M. Orešković, J. Benić, M. Essert, The Network Integrator of Croatian Lexicographical Resources, XVII EURALEX International Congress, Tbilisi, Georgia, 2016, 267-273
   Abstract

   In this paper we describe an online application which connects various Croatian lexicographical sources (the standard dictionary, professional terminology, and encyclopedias) into a new network framework, which solves the problems of the currently available network solutions and offers new features. Although developed for the formation and processing of the professional terminology of technical sciences (primarily engineering), this framework is easily extensible to all other science areas (humanities, medicine, architecture, etc.). From a word formation standpoint, this framework provides an automatic generation of a temporary dictionary of a given text (entered or taken from the web), comparison of and updating a permanent dictionary with a temporary one (detection of neologisms), an automatic display (standard, professional and encyclopedic) of definitions of the words from the main dictionary or external (network) sources of a given text. From the point of view of processing, the framework enables a classic text analysis (frequency, concordances, statistics), converting the collected data (e.g. technical words) to the linked open data (LOD), and storing it into the Virtuoso triplestore repository. On this data, a variety of professional ontologies for viewing and searching can be developed.

Professional Activities

Seminars and Talks

• 21.2.2019. “Upravljanje izravno pogonjenih elektrohidrauličkih sustava”, na seminaru Servohidraulika, Fakultet strojarstva i brodogradnje

Invited Lectures

• 8.6.2021. “Direct Driven Hydraulic and Internet of Things”, University of Maribor, faculty of Mechanical Engineering

Study Visits Abroad

• 21.3.2024. – 29.3.2024., M. O. Auezov South Kazakhstan State University, Kazakhstan