Spacecraft (S/C) docking is the last and most challenging phase in the contact closure of two separately flying S/C. The design and testing of S/C docking missions using software-multibody simulations need to be complemented by Hardware-In-The-Loop (HIL) simulation using the real docking hardware. The docking software multibody simulation is challenged by the proper modeling of contact forces, whereas the HIL docking simulation is challenged by proper inclusion of the real contact forces. Existing docking HIL simulators ignore back-reaction force modeling due to the large S/C sizes, or use compliance devices to reduce impact, which alters the actual contact force. This dissertation aims to design a docking HIL testbed to verify docking contact dynamics for small and rigid satellites by simulating the real contact forces without artificial compliance. HIL simulations of docking contact dynamics are challenged mainly by: I. HIL simulation quality: quality of realistic contact dynamics simulation relies fundamentally on the quality of HIL testbed actuation and sensing instrumentation (non-instantaneous, time delays, see Fig. 1) II. HIL testbed design: HIL design optimization requires a justified HIL performance prediction, based on a representative HIL testbed simulation (Fig. 2), where appropriate simulation of contact dynamics is the most difficult and sophisticated task. The goal of this dissertation is to carry out a systematic investigation of the technically possible HIL docking contact dynamics simulation performances, in order to define an appropriate approach for testing of docking contact dynamics of small and rigid satellites without compliance and using HIL simulation. In addition, based on the investigations, the software simulation results shall be validated using an experimental HIL setup. To achieve that, multibody dynamics models of docking S/C were built, after carrying out an extensive contact dynamics research to select the most representative contact model. Furthermore, performance analysis models of the HIL testbed were built. In the dissertation, a detailed parametric analysis was carried out on the available models’ design-spaces (e.g., spacecraft, HIL testbed building-blocks and contact dynamics), to study their impacts on the HIL fidelity and errors (see Fig. 1). This was done using a generic HIL design-tool, which was developed within this work. The results were then used to identify the technical requirements of an experimental 1-Degree-of-Freedom (DOF) HIL testbed, which was conceived, designed, implemented and finally utilized to test and validate the selected docking contact dynamics model. The results of this work showed that the generic multibody-dynamics spacecraft docking model is a practical tool to model, study and analyze docking missions, to identify the properties of successful and failed docking scenarios before it takes place in space. Likewise, the 'Generic HIL Testbed Framework Analysis Tool' is an effective tool for carrying out performance analysis of HIL testbed design, which allows to estimate the testbed’s fidelity and predict HIL errors. Moreover, the results showed that in order to build a 6DOF HIL docking testbed without compliance, it is important to study and analyze the errors’s sources in an impact and compensate for them. Otherwise, the required figure-of-merits of the instruments of the HIL testbed would be extremely challenging to be realized. In addition, the results of the experimental HIL simulation (i.e., real impacts between various specimen) serve as a useful contribution to the advancement of contact dynamics modeling.

La commande du système de Direction Assistée Electrique (DAE) est un défi majeur en raison de ses multiples objectifs et de la nécessitée de réaliser plusieurs mesures pour la mettre en oeuvre. La commande doit assurer : le suivi du couple d’assistance de référence tout en assurant la stabilité du système et sans introduire des retards, l’atténuation des vibrations provoquées par chacune des entrées du système, la transmission des informations de la route au conducteur pour un bon confort et une meilleure sensation de conduite, l’amélioration de la performance de retour au centre. La commande doit également être robuste vis-à-vis des erreurs de modélisation, des incertitudes des paramètres, et des perturbations extérieures. En outre, la mise en oeuvre de la commande nécessite plusieurs mesures telles que : l’angle au volant, l’angle du moteur, la vitesse du moteur, le couple conducteur et le couple de réaction de la route. / The control of Electric Power Assisted Steering (EPAS) system is a challengingproblem due to the multiple objectives and the need of several pieces of information to implement the control. The control objectives are to generate assist torque with fast responses to driver’s torque commands, insure system stability, attenuate vibrations, transmit the road information to the driver, and improve the steering wheel returnability and free control performance. The control must also be robust against modeling errors and parameter uncertainties. In addition, several pieces of information are required to implement the control, such as steering wheel angle, motor velocity, driver torque and road reaction torque.

The use of simulation enables testing of a system without the need for a complete physical system, while also having the advantages of lower cost and fewer practical limits compared to field tests. Hardware may be integrated into the simulation loop, such a simulation is defined as a Hardware-in-the-loop (HIL) simulation. The pump is the most energy-consuming part of a pumping station, thus improvement and assessment of the pump controller are two of the main considerations in the development of pumping stations. Nevertheless, the developers do not always have access to a real pumping station to run tests on. A HIL simulator that imitates parts of a pumping station while including a real controller in the simulation is therefore desirable for the development of pump controllers.In this thesis, a mathematical model of a pumping station was built based on the physical features of different components, and a HIL simulation was implemented with the programming language Python, in which a real controller was integrated into the simulation loop. Through a three-hour-long simulation run, the functionality of the simulator has been analyzed, and the simulation accuracy was evaluated by comparing simulated results to real data. The results showed that among the 10 800 simulated data points of the water level, there were \(43\) (\(\approx 0.39\%\)) that had a relative change larger than \(30\%\) or less than \(-30\%\) with respect to the field data. This thesis contributes to the field of Python-based simulation of a pumping station, and serves as a foundation for future improvement for the host company. / Användningen av simulering möjliggör testning av ett system utan ett komplett fysiskt system, till en lägre kostnad och färre praktiska begränsningar jämfört med fälttester. Hårdvara kan integreras i simuleringsloopen, en sådan simulering kallas för en hardware-in-the-loop (HIL) simulering. Pumpen är den mest energikrävande delen i en pumpstation, därför är förbättring och utvärdering av pumpstyrningen två av de viktigaste faktorerna vid utvecklingen av pumpstationer. Dock har utvecklarna inte alltid tillgång till en fysisk pumpstation att köra tester på. En HIL-simulator som imiterar delar av en pumpstation, till vilken en pumpstyrning kan kopplas, är därför önskvärd för utvecklingen av pumpstyrningar.I detta examensarbete konstruerades en matematisk modell av en pumpstation utifrån de fysiska egenskaperna hos olika komponenter. En HIL-simulator var sedan implementerad i programmeringsspråket Python, där en riktig pumpstyrning integrerades i simuleringsloopen. Genom en tre timmar lång körning har simulatorns funktionalitet analyserat, och simuleringsnoggrannheten utvärderades genom att jämföra simulerade resultat med verkliga data. Resultaten visade att \(43\) av de 10 800 (\(\approx 0,39\%\)) simulerade datapunkterna för vattennivån hade en relativ förändring större än \(30\%\) eller mindre än \(-30\%\) med avseende på fältdata. Detta arbete bidrar till området inom Python-baserad simulering av en pumpstation och agerar som en grund för framtida utvecklingar hos värdföretaget.

Hardware-in-the-loop (HiL) is a concept for testing physical equipment by connecting itto a mathematical representation (model) of the physical process. HiL-testing reduces thecost and saves time before testing the physical equipment (hardware) on the real (physical)process. The physical process chosen for this study is wire+arc additive manufacturing(WAAM), an advanced additive manufacturing (AM) technology that deposits metalbased material layer-by-layer. In this study, simulations of the robot path are carried outwhile the physical robot performs a physical process (additive manufacturing). In robotadditive manufacturing, the desired CAD model is currently sliced down into layers usingslicer software, and the layers are then translated into a path. The robot then moves alongthe path of these pre-defined layers to produce a three-dimensional structure. The heightof the produced structures and desired CAD models have deviations because of processinstabilities and temperature variations among other factors. The robot path should beupdated every time a layer is printed to compensate for the height differences. This isachieved by parametrizing the CAD model, i.e., the CAD model of the structure to beprinted is replaced by a mathematical equation (model). In this study, the mathematicalmodel is updated for each layer in real-time with feedback data from sensors that monitorthe additive manufacturing process. The concept of updating a mathematical model andexecuting it in real-time is called real-time simulation (RTS). In this study, a HiL-basedreal-time simulation setup has been developed, which predicts the required printing layerheight and the number of layers (based upon the latest feedback data from the monitoringsensors), and the required height of the structure. By combining hardware and software,a cyber-physical system has been created, enabling the transition from automation toautonomous robotics and contributing to Industry 4.0.