To control the speed of an overactuated vehicle there may be many possible ways to use the actuators of the car achieving the same outcome. The actuators in an ordinary car is a combustion engine and a friction brake. In some cases it is trivial how to coordinate actuators for the optimal result, but in many cases it is not. The goal with the thesis is to investigate if it is possible to achieve the same or improved performance with a more sophisticated control structure than today's, using a model predictive controller. A model predictive controller combines the possibility to predict the outcome through an open-loop controller with the stability of a closed loop controller and gives the optimal solution for a finite horizon optimization problem. A simple model of the longitudinal dynamics of a car is developed and used in the model predictive controller framework. This is then used in simulations and in a real car. It is shown that it is possible to replace the current controller structure with a model predictive controller, but there are advantages and disadvantages with the new control structure.

The goal of this thesis was to evaluate sensors and motor speed control methods for BLDC/PMSM motors in Aerospace applications. The sensors and methods were evaluated by considering accuracy, robustness, cost, development gain and parameter sensitivity. The sensors and methods chosen to simulate were digital Hall sensors and sensorless control of BLDC motors. Using Matlab Simulink/Simscape some motor speed control methods and motor speed estimation methods were simulated using the Hall sensors and sensorless control as a basis. It was found that the sensorless control methods for BLDC motors couldn't estimate the speed accurately during dynamic loads and that the most robust and accurate solution based on the simulations was using the digital Hall sensors for both speed estimation and commutation and this was tested on a hardware setup.

This master's thesis aims to investigate how fuzzy logic can be used to adapt the tuning of a speed control law during certain conditions such as turbulence. The objective is to lower the speed overshoot caused by the auto-thrust function as well as the general engine agitation. The main modifications studied are direct lowering of the closed loop gains, hybridisation and filtering of the longitudinal acceleration estimation. Finally, saturations or limits on the control signal as well as on the coordination with the longitudinal control law are studied in order to cope with the possible consequences of a softer control law. To detect the turbulence, an already existing turbulence detector is used. In addition, a wind gradient detector is designed in order to increase the gain during such wind conditions to counter ramp errors. It is found that a general lowering of the closed loop gain in combination with a slow hybridisation, all proportional to the detected turbulence level, together with a limitation of the coordination gives a satisfactory result. In scenarios including severe turbulence and wind gradients, the forced limits are shown to be indispensable. A conclusion is drawn that the fuzzy tuning is better adapted to turbulent conditions but that the wind gradient detection and the forced limits must be studied further. It is also concluded that the coupling between the closed loop gain and the acceleration hybridisation can be interesting to investigate. Moreover, additional realistic scenarios should be simulated in order to further validate the design. For future studies on the subject; it is recommended that the controller tuning is validated with the help of expert knowledge. Alternatively, the tuning could be handled by an ANFIS (Adaptive Neuro Fuzzy Inference System). Finally the tuning of the controller should be validated for a wider range of flight points, most importantly the forced limits since the engine response varies a lot between different points in the flight envelope.

<p> The speed of a squirrel-cage induction motor is controlled by varying the supply frequency. The design of an SCH controlled inverter, using gating from a logic unit to give a variable-frequency power-level output, is described.</p> / Thesis / Master of Engineering (MEngr)

No description available.

This thesis has reviewed two aspirationssystems at Viking Malt in Halmstad, Sweden. Based on this different optimization solutions has been developed for aspirationssystem 180 and 901. Viking Malt has several of plants and is the fifth largest producer of malt in Europe. As a company they constantly strive to be an energy efficient company to compete on the market. During 2015 over 200 00 ton of malt was delivered from the plant, enough to brew 1,6 billion liter of beer. From the corn reception to the finished malt, large portions of dust are created. This has to be taken care of to avoid danger of fire and to ensure a clean product. This is achieved by exhaust fans who aspirate the dusty air from the process steps where its needed, with big filters the dust is separated from the air. In the plant frequency converters are installed on aspirationsline 180 and 901 these are currently set to have the same max and min frequency, which means no speed control is currently active on the fans. The reason behind this is because consultants have not come up with any concrete solution proposals to Viking Malt so the issue has been put aside. To investigate the aspirationssystem and to clarify the problem with the frequency converters has measurements of airflow and tests with the frequency converters been done. Through treatment of earlier investigations of the aspirationssystem, discussion with the employees and new survey efficiency proposals has been identified. From calculations and investigations of the aspirationssystem three different options has been presented. The thesis has designed an action plan that Viking Malt may use as a tool to identify which option is the most relevant. / Examensarbetet har systemgranskat och bearbetat fram optimeringsmöjligheter på Viking Malts aspirationssystem på linje 180 och 901 i Halmstad. Viking Malt har ett flertal anläggningar i Norden och är Europas femte största maltproducent. Företaget strävar ständigt efter att effektivisera driften och kvalitén för att kunna vara konkurrenskraftig på marknaden. Under 2015 levererades över 200 000 ton malt från anläggningen vilket skulle räcka till att brygga 1 600 000 m3 öl. Från kornmottagning till färdigställd malt sker det stora dammbildningar som måste ledas bort för att undvika explosionsrisker och försämring av produktens kvalité. Detta uppnås med hjälp av frånluftsfläktar som aspirerar dammfylld luft ifrån processteg där behovet finns, och med hjälp av aspiration kan damm extraheras från luften. I anläggningen sitter det frekvensomformare på linje 180 och 901 som idag har samma max och min frekvens vilket betyder att det inte sker någon varvtalsreglering på fläktarna. Anledning till denna åtgärd är att aspirationen inte fungerar som den ska. För att undersöka aspirationsanläggningen och klargöra problematiken med styrningen har mätningar av luftflödet samt test av frekvensomformare utförts. Genom studera tidigare utredningar, ny kartläggning av aspirationslinjerna och diskussion bland personal har optimeringsförslag identifierats. Utifrån tryckfallskalkyler av aspirationslinjerna 180 och 901 har tre ändringsförslag presenterats. Examensarbetet har även utformat en handlingsplan som Viking Malt kan använda som ett verktyg för de åtgärder som blir relevant. Med implementering av något av de tre åtgärdsförslagen blir systemet anpassat efter erfordrat tryckfall, detta innebär att produktkvalitet kan säkerställas. Utöver detta finns det möjlighet till energibesparing upp till 23,2 MWh/år beroende av optimeringsåtgärd.

A major traffic-related problem faced by residents is speeding, which not only causes safety concerns, but also noise issues. Traffic calming is a much favoured traffic management tool employed by road controlling authorities to primarily reduce vehicle speed, hence improve community liveability. This research aimed to investigate the impacts of traffic calming on speed, safety and traffic noise. The objectives included developing models for the prediction of speed and noise on traffic-calmed streets, and providing guidance for good design practices. Speeds of individual vehicles as they approached and crossed traffic calming devices were observed in order to identify the behaviour of individual drivers. Results indicated that the speed hump and the raised angled slow point produced the largest speed reductions and least variation in speeds, while mid-block narrowings had no significant speed changes. Inter-device speed was found to be mainly controlled by the separation between devices. 85th percentile speeds at distances from calming devices were 40 – 45 km/h for vertical deflections and 45 – 55 km/h for horizontal deflections. Speeds on approach to speed humps were found to be influenced by the distance available on the approaches, while operating speed at the speed humps were partly influenced by the hump width relative to the road width. There was evidence of safety benefits of traffic calming overall, despite mid-block crashes increasing post-calming. However, there was no association between the traffic calming and the crashes, which appeared to probably be due to other factors, human factors in particular. Noise levels produced by light vehicles across speed humps were in fact lower than on a flat section of road, given their respective mean speeds. At a reference speed of 25 km/h, noise levels produced over the 100 mm hump were 3.6 dBA higher than those produced by the 75 mm hump.

<p>The use of positioning systems in a vehicle is a research intensive field. In the first part of this thesis an increase in new applications is disclosed through a mapping of patent documents on how positioning systems can support adaptive cruise control, gear changing systems and engine control. Many ideas are presented and explained and the ideas are valued. Furthermore, a new method for selective catalytic reduction (SCR) control using a positioning system is introduced. It is concluded that look-ahead control, where the vehicle position in relation to the upcoming road section is utilized could give better fuel efficiency, lower emissions and less brake, transmission and engine wear.</p><p>In the second part of this thesis a real time test platform for predictive speed control algorithms has been developed and tested in a real truck. Previously such algorithms could</p><p>only be simulated. In this thesis an algorithm which utilizes model predictive control (MPC) and dynamic programming (DP) been implemented and evaluated. An initial comparative fuel test shows a reduction in fuel consumption when the MPC algorithm is used.</p>

The use of positioning systems in a vehicle is a research intensive field. In the first part of this thesis an increase in new applications is disclosed through a mapping of patent documents on how positioning systems can support adaptive cruise control, gear changing systems and engine control. Many ideas are presented and explained and the ideas are valued. Furthermore, a new method for selective catalytic reduction (SCR) control using a positioning system is introduced. It is concluded that look-ahead control, where the vehicle position in relation to the upcoming road section is utilized could give better fuel efficiency, lower emissions and less brake, transmission and engine wear. In the second part of this thesis a real time test platform for predictive speed control algorithms has been developed and tested in a real truck. Previously such algorithms could only be simulated. In this thesis an algorithm which utilizes model predictive control (MPC) and dynamic programming (DP) been implemented and evaluated. An initial comparative fuel test shows a reduction in fuel consumption when the MPC algorithm is used.

Sliding mode controllers (SMC) with time delay and a rotor position observer are designed for the sensorless speed control of permanent magnet synchronous motor (PMSM) are proposed in this paper. Based on field-oriented principle, a flux SMC is designed to achieve quick flux control. And then a speed SMC with time delay is presented and compared with PI controller in the direct torque control framework. The effectiveness of the proposed control scheme under the load disturbance and parameter uncertainties is verified by simulation results.