<p>The purpose of the thesis has been to design and simulate different concepts of a secondary controlled swing drive for a wheel excavator. Secondary control is a known technology in the field of hydraulics that offers precise positioning as well as the possibility of energy recuperation. Secondary control is today used in certain industrial applications and is rather unemployed in mobile machinery. An excavator moves high loads in cyclic motions which are ideal conditions for energy recuperating systems. A study of the potential of a secondary controlled swing drive is therefore interesting. The focus has been on testing different circuit architectures and emergency brake concepts.</p><p>The results of the design process have been three types of circuit architectures and two types of hydraulic safety concepts. The results of the simulation have shown that the open and closed circuit architecture have similar energy efficiency. The closed circuit with low pressure accumulator however offers the best controllability. At least 20% energy savings can be achieved by storing thekinetic energy when braking.</p><p>A hydraulic emergency brake must function, independent on the direction of rotation of the excavator during a failure. The first principle recognises the rotation direction and changes the swivel angle of the secondary unit so that a braking torque is created. In the second principle a pressure difference is built up over the secondary unit that always results in a braking torque. Simulationshave shown that the principle with recognition of the speed direction is the most effective safety concept.</p>

<p>Hydrostatic transmission is used in many applications where high torque at low speed is demanded. For this project a forest vehicle is at focus. Komatsu Forest would like to have a model for the pressure in the hose between the hydraulic pump and the hydraulic motor. Pressure peaks can arise when the vehicle changes speed or hit a bump in the road, but if a good model is achieved some control action can be developed to reduce the pressure peaks.</p><p>For simulation purposes a model has been developed in Matlab-Simulink. The aim has been to get the simulated values to agree as well as possible with the measured values of the pressure and also for the rotations of the pump and the motor.</p><p>The greatest challenge has been due to the fact that the pressure is a sum of two flows, if one of these simulated flows is too big the pressure will tend to plus or minus infinity. Therefore it is necessary to develop models for the rotations of the pump and the motor that stabilize the simulated pressure.</p><p>Different kinds of models and methods have been tested to achieve the present model. Physical modeling together with a black box model are used. The black box model is used to estimate the torque from the diesel engine. The probable torque from the ground has been calculated. With this setup the simulated and measured values for the pressure agrees well, but the fit for the rotations are not as good.</p>

The purpose of the thesis has been to design and simulate different concepts of a secondary controlled swing drive for a wheel excavator. Secondary control is a known technology in the field of hydraulics that offers precise positioning as well as the possibility of energy recuperation. Secondary control is today used in certain industrial applications and is rather unemployed in mobile machinery. An excavator moves high loads in cyclic motions which are ideal conditions for energy recuperating systems. A study of the potential of a secondary controlled swing drive is therefore interesting. The focus has been on testing different circuit architectures and emergency brake concepts. The results of the design process have been three types of circuit architectures and two types of hydraulic safety concepts. The results of the simulation have shown that the open and closed circuit architecture have similar energy efficiency. The closed circuit with low pressure accumulator however offers the best controllability. At least 20% energy savings can be achieved by storing thekinetic energy when braking. A hydraulic emergency brake must function, independent on the direction of rotation of the excavator during a failure. The first principle recognises the rotation direction and changes the swivel angle of the secondary unit so that a braking torque is created. In the second principle a pressure difference is built up over the secondary unit that always results in a braking torque. Simulationshave shown that the principle with recognition of the speed direction is the most effective safety concept.

Hydrostatic transmission is used in many applications where high torque at low speed is demanded. For this project a forest vehicle is at focus. Komatsu Forest would like to have a model for the pressure in the hose between the hydraulic pump and the hydraulic motor. Pressure peaks can arise when the vehicle changes speed or hit a bump in the road, but if a good model is achieved some control action can be developed to reduce the pressure peaks. For simulation purposes a model has been developed in Matlab-Simulink. The aim has been to get the simulated values to agree as well as possible with the measured values of the pressure and also for the rotations of the pump and the motor. The greatest challenge has been due to the fact that the pressure is a sum of two flows, if one of these simulated flows is too big the pressure will tend to plus or minus infinity. Therefore it is necessary to develop models for the rotations of the pump and the motor that stabilize the simulated pressure. Different kinds of models and methods have been tested to achieve the present model. Physical modeling together with a black box model are used. The black box model is used to estimate the torque from the diesel engine. The probable torque from the ground has been calculated. With this setup the simulated and measured values for the pressure agrees well, but the fit for the rotations are not as good.

Wave Energy Converters (WEC) are used to transform energy stored in ocean waves into electrical energy. One type of WECs consists of buoyant bodies. To extract energy from their motion, hydraulic cylinders can be used to generate hydraulic power. For conversion into electric power various systems have been analysed in literature. However, the focus was put on efficiency and rigorous analyses of the system behaviour are still missing. In this paper an exemplary system consisting of two hydraulic cylinders, switchable check valves, accumulators and three motor-generator sets is analysed with help of simulation and measurement. This exemplary system is called WavePOD and was installed at the Institute for Fluid Power Drives and Controls (IFAS) of RWTH Aachen University together with Aquamarine Power and Bosch Rexroth for testing. In this paper the data collected during various test phases is used for system analysis and for validating the simulation. The simulation model is presented. The system’s response to various switching operations is investigated. Comparing the simulation with measurements validates the system`s dynamic model.

Wave Energy Converters (WEC) are used to transform energy stored in ocean waves into electrical energy. One type of WECs consists of buoyant bodies. To extract energy from their motion, hydraulic cylinders can be used to generate hydraulic power. For conversion into electric power various systems have been analysed in literature. However, the focus was put on efficiency and rigorous analyses of the system behaviour are still missing. In this paper an exemplary system consisting of two hydraulic cylinders, switchable check valves, accumulators and three motor-generator sets is analysed with help of simulation and measurement. This exemplary system is called WavePOD and was installed at the Institute for Fluid Power Drives and Controls (IFAS) of RWTH Aachen University together with Aquamarine Power and Bosch Rexroth for testing. In this paper the data collected during various test phases is used for system analysis and for validating the simulation. The simulation model is presented. The system’s response to various switching operations is investigated. Comparing the simulation with measurements validates the system`s dynamic model.

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Scandinavian Terrain Vehicles AB (STV) konstruerar och bygger bandvagnar för civilt bruk. I utbudet ingår även vad STV kallar Mid Life Improvement (MLI) vilket syftar i att renovera Hägglunds BV206. En del av MLI-programmet är byte av motor och växellåda där de gamla komponenterna från sent 80-tal till tidigt 90-tal byts ut mot ny motor och växellåda. Den nya kombinationen av motor och växellåda möter militär standard och blir därför en onödigt kostsam del då många av STV:s kunder skulle vara nöjda även med ett enklare alternativ. För att minska kostnaden för MLI-programmet och därmed potentiellt utöka kundkretsen undersöktes möjligheterna till att hitta nya leverantörer av motor och växellåda. Som alternativ undersöktes möjligheterna till drift genom diesel- eller Ottomotor samt transmission av typerna automatisk växellåda, hydrostatisk och elektrisk transmission. Sökning av komponenter utgick från att undersöka vilka komponenttillverkare som används av liknande applikationer. Genom en kriterieviktsmetod blev det rekommenderade lösningsalternativet motorn Cummins ISF 2.8 120 kW och växellådan Allison 1000SP. Kombinationen levererar som mest 1384 Nm och vid 5200 rpm 185 Nm till fördelningsväxeln. Resultatet styrks av att motorn enligt tillverkaren är lämpad för fordon såsom mindre lastbilar och terrängfordon samt att växellådor av samma tillverkare används till bland annat BAE Systems Hägglunds bandvagn BvS10. / Scandinavian Terrain Vehicles AB (STV) is a company that designs and builds tracked vehicles for civilian usage. One of their services is what they call Mid Life Improvement (MLI) which serves to recondition Hägglunds BV206’s. A significant part of the MLI-program is the exchange of engine and transmission where components from the late 80’s to early 90’s are replaced with new parts. The new parts consist of a combination of engine and gearbox that meets military standards and is therefore an expensive part especially since many of STV’s customers would settle with a more elementary alternative. To reduce costs within the MLI-program and potentially expand clientele STV sought to find new suppliers for engine and gearbox. Considered alternatives for replacement were Otto- and Diesel engines in coupled with a transmission in the form of either an automatic gearbox, a hydrostatic or an electric transmission. By examining which suppliers were being used by similar applications and selection through a weighted criteria method, the engine Cummins ISF 2.8 120 kW and transmission Allison 1000SP were found to be the best suited alternative. The combination delivers to the distribution gearbox a maximum torque of 1384 Nm and 185 Nm at 5200 rpm. The result is attested by the fact that the engine is according to the manufacturer suitable for applications like trucks and utility vehicles together with that the same brand of transmission is used by BAE Systems Hägglunds in their BvS10.

Táto diplomová práca sa zaoberá vytvorením dynamického modelu mobilného pracovného stroja. Ciežom práce je vytvorenie blokového modelu pohonu štvorkolesového mobilného pracovného stroja. Model hydrostatického prevodu bol dodaný firmou Sauer-Danfoss. Model mobilného pracovného stroja bol vytvorený v programe MATLAB-Simulink. Dalšou časťou práce je výber typu riadenia hydrostatického prevodu a návrh riadiaceho algoritmu hydrostatického prevodu. Výstupom práce je blokový matematicko-fyzikálny model pohonu štvorkolesového mobilného pracovného stroja spolu s riadiacim algoritmom hydrostatického prevodu v prostredí MATLAB-Simulink.

To cope with the increasing demand of a more sustainable mobility, the main Original Equipment Manufacturers are producing vehicles equipped with hybrid propulsion systems that increase the overall vehicle efficiency and mitigate the emission problem at a local level. The newly gained degrees of freedom of the hybrid powertrain need to be handled by advanced energy management techniques that allow to fully exploit the system capabilities. In this thesis we propose an optimal control approach to the solution of the energy management problem, putting emphasis on the importance of accurate models for the reliability of the optimization solution. In the first part of the thesis we address the energy management problem for a hybrid electric vehicle, including the mitigation of the battery aging mechanisms. We show that, with an optimal management strategy, we could extend the battery life up to 25% for some driving cycles while keeping the fuel savings performance substantially unaltered. In the second part of the thesis we focus on the hydrostatic hybrid transmission, a different hybridization solution that is able to fulfill the high power demand of heavy duty off-highway vehicles. Also in this case, we formulate the energy management problem as an optimal control problem, dealing with the complexity introduced by the discrete valve actuations in the framework of mixed-integer optimal control. We show that, using hydraulic accumulators to recover energy from the regenerative braking, we could reduce fuel consumption up to 13% for a typical driving cycle. In the third and last part of the thesis we show how the optimization approach can be used to systematically design and calibrate control algorithms, casting the calibration problem into a Linear Matrix Inequality. We first develop a non-overshooting closed-loop control for the actuation pressure of a wet clutch, proving the effectiveness of the control on an experimental setup. Finally, we focus on the design of a dead-zone based kinematic observer for the estimation of the lateral velocity of a road vehicle. The structure of the observer presents good noise rejection performance, allowing for the selection of a higher observer gain that improves the estimation accuracy.