This diploma thesis deals with a concept and strength analysis of a low loader trailer for construction machinery. The thesis was created in cooperation with company ZDT Nové Veselí. The first part presents an overview of ways how to transport construction machinery and fundamental legal requirements for these devices. The main part of the thesis contains description of the trailer and its simplified model intended for the strength analysis. The last section presents an evaluation of results that had been achieved and at the very end the thesis contains partial drawing documentation.

This diploma thesis deals with the creation of models simulating the processes of an emission-free wheel loader, which was created by rebuilding the original version with a combustion engine. Part of the work is the methodical creation of models from the basic part of the machine to a simplified model of the overall machine, its functional verification and calibration based on available information’s and measurements. In this paper, selected parameters of the overall machine model are verified based on performed measurements, the suitability of selected components is verified, and the optimization and modification of the model is performed based on verification. The aim of the thesis is to present the simulation and verification procedure and its practical use in the development of an emission-free wheel loader with electric drive.

The object of this diploma thesis is revision of coolant system skid steer loaders “BOBEK” B861, B961 and his eventually optimization for prevention of overheating hydraulic system and engine. The first part dedicate of general issues of coolant skid steer loaders. The second part is the calculation during heat stress hydraulic systems of loader and the third part include proposals for solutions problems of overheating hydraulic systems and combustion engine.

Hydraulics has always been the first choice of actuation in off-road, construction and mining vehicles due to its power density, low cost, built in cooling and lubrication. However, the current state of our environment along with stricter regulations has brought light to newer technologies within hydraulics to improve the existing system. This urge to enhance efficiency and reduce energy consumption has led to a point where new technologies must be evaluated. One such technology is the programmable hydraulic pump called the digital displacement pump (DDP). This new pump may have the potential to revolutionize mobile hydraulics as it can be used to improve part load efficiencies, response and make it easier to control from a system perspective. The DDP is a radial piston pump that has been fit with solenoid on/off valves at the inlet of each cylinder to control the flow of the working fluid. The displacement setting of the pump depends on the displacement of each cylinder controlled digitally by the 'active' inlet valve. The pump can act as a single unit to supply one circuit or it can dedicate pistons for supplying several circuits in parallel using different pump outlet configurations. They can be setup to run in pressure controlled or flow controlled systems to achieve the above mentioned flow sharing capability. An energy study based on two fixed drive cycles (short and intermediate) are conducted on the existing system of a loader used for mining called the ST14 Battery. A breakdown of the energy consumption in the machine is created to look at the impact of the three main actuators (boom, bucket and steering), pump losses and throttling losses have. The losses due to simultaneous load handling and the energy that can be saved by swapping the pumps with a digital displacement pump are also found out and analysed. A model of the existing hydraulic system is made using Simulink and Hopsan using the data and results from the energy study. It will be used to simulate and evaluate future system architectures. This model is then used to simulate a system architecture where the existing pumps are swapped with digital displacement pumps. This architecture is more energy efficient due to the higher energy efficiency of the pump. The findings from the energy study and simulations are compared and results are obtained regarding power losses, energy consumption and overall usability of the models. The addition of the two DDP’s instead of the existing inline pumps has resulted in energy savings resulting in 4% more running time in the intermediate cycle and 5.6% in the short cycle while keeping the functionality of the machine.

The present paper describes an innovative electro-hydraulic system developed for automated side loaders. The system is based on Intelligent Flow Control (IFC), a concept where open circuit electric displacement controlled pumps are coupled with EH directional control valves. IFC was selected in order to achieve the level of performance required, in terms of efficiency and productivity (i.e. cycle times), and also to provide the best possible control of the side loader arm. The paper describes the system layout and the basics of the controls: from the alghorithms of the arm actuators to the vehicle on board telemetry and diagnostic. The paper reports the comparison between the IFC system (implemented on the vehicle) and a more traditional approach based on a Load Sense Flow Sharing concept. The benefits of the IFC solution are highlighted focusing on the energy efficiency (very important especially in the case of CNG engines, where the torque available at idle is significantly lower than diesel engines), but also in terms of controlability and response (due to the lack of load sensing signal lines).

Wheel loaders are heavy duty machines that are ubiquitous on construction sites and in mines all over the world. Fully autonomous wheel loaders remains an open problem but the industry is hoping that increasing their level of autonomy will help to reduce costs and energy consumption while also increasing workplace safety. Operating a wheel loader efficiently requires dig plans that extend over multiple dig cycles and not just one at a time. This calls for a model that can predict both the performance of a dig action and the resulting shape of the pile. In this thesis project, we use simulations to develop a data-driven artificial neural network model that can predict the outcome of a dig action. The model is able to predict the wheel loader’s productivity with an average error of 7.3% and the altered shape of the pile with an average relative error of 4.5%. We also show that automatic differentiation techniques can be used to accurately differentiate the model with respect to input. This makes it possible to use gradient-based optimization methods to find the dig action that maximises the performance of the wheel loader.

Web environment has developed into the largest source of electronic documents, so it would be very useful, to process this information automatically. This is however not a trivial problem. Most documents are written in HTML (Hypertext Markup Language), which does not support semantic description of the content. The goal of this work is to create modular system for information extraction and further processing of this information from HTML documents. Further processing of information means to store this information in XML document or relational database. System modularity makes it possible to use various information extraction and storing methods, thus the system can be used for various tasks.

Volvo Construction Equipment is one of the leading construction machinery manufacturers in the world. To stay amongst the leaders, research and development projects for new technologies are crucial. The most important path of development today is the reduction of emissions produced by these heavy duty vehicles. To tackle this challenge, several technologies are already used in industry. One example are hybrid machines that combine a conventional diesel engine with batteries, resulting in reduced engine size and pollutants. Another option are full battery-electric vehicles, which can reduce the on-site emissions to zero. The electrochemical processes within batteries are however comparable slow and result in long recharge times. A new focus of development within the industry are hybrid systems combining fuel cells and batteries. Since hydrogen can be refueled almost as fast as convenient fuel, it solves the issue of long recharge times. Additionally, the reaction is emission free, since there is no combustion process and the only byproduct that is emitted from the fuel cell is chemically clean water. This thesis aims to propose an architecture and packaging solution to replace the diesel engine in a large size wheel loader with a fuel cell power system. This also includes all respective auxiliary systems, i.e. energy storage, cooling and electric systems. Achieving the same performance as a conventional large size wheel loader as well as keeping the spatial envelope the same are the main objectives of this work. To achieve these goals, an extensive study on the most common drive cycles is carried out to understand the power demand of the machine. After the selection of an energy storage system based on a MATLAB simulation script, a cooling system is modelled and scaled to fulfill the operating requirements of the different components. Eventually, all systems are modeled and installed into the wheel loader in CATIA V5. The study showed, that the new system architecture of the vehicle can be fitted into the existing engine bay with a slight extension of the rear frame and hood. Two power optimized batteries are combined with one fuel cell. Hydrogen tanks with a filling volume of 478 [L] can be installed in the machine, covering 50% of the customer population curve without degradation of performance. This includes one refill of the wheel loader during the day. The performance parameters match the conventional machine up to a high degree, concluding that the conversion of a large size wheel loader into a fuel cell powered wheel loader is feasible.

This thesis aims to create a system using colour markings for Volvo’s autonomous wheel loaders which determines their restricted area and operation using sensors available on the machine. The wheel loader shall be able to interpret and distinguish different colours of spray paint, and depending on the colour, act accordingly. Six different colours are evaluated across two different colour types to find the most suitable ones for the system. Multiple tests are presented throughout the thesis to find the approach with the most optimal performance that meets the system's requirements. The system is evaluated in various weather conditions to determine how the weather affects the performance of the system. The thesis also compares two different line-following approaches, where one is based on edge detection using Canny Edge and Hough transform, and the other uses histogram analysis and sliding window search, to distinguish and track the colour markings. While the wheel loader is in operation, it collects GPS coordinates to create a map of the path taken by the wheel loader and the location of various tasks. The evaluation shows that red, green and blue in fluorescent colour type are the most suitable colours for such a system. The line-following algorithm that utilises perspective warp, histogram and a sliding window search was the most prominent for accurate line detection and tracking. Furthermore, the evaluation showed that the performance of the system was affected depending on the weather condition.

In recent years many companies have investigated the use of hybrid technology due to the potential of increasing the driveline’s efficiency and thus reducing fuel consumption. Previous studies show that hydraulic hybrid technology can be favourable to use in construction machinery such as wheel loaders, which often operate in repetitive drive cycles and have high transient power demands. Parallel as well as Series hybrid configurations are both found suitable for wheel loader applications as the hybrid configurations can decrease the dependency on the torque converter. This project has investigated a novel hydraulic hybrid concept which utilizes the wheel loaders auxiliary pump as a supplement to enable both Series and Parallel hybrid operation. Impact of accumulator sizes has also been investigated, for which smaller accumulator sizes resembles a hydrostatic transmission. The hybrid concept has been evaluated by developing a wheel loader simulation model and a control system based on a rule-based energy management strategy. Simulation results indicate improved energy efficiency of up to 18.80 % for the Combined hybrid. Moreover, the accumulator sizes prove to have less impact on the energy efficiency. A hybrid system with decreased accumulator sizes shows improved energy efficiency of up to 16.40 %.