Current one-handed manual wheelchairs are difficult to propel because one arm can only provide half the power that is ascertained in a two-handed manual wheelchair. A power-assisted hemiplegic (one-sided paralysis) wheelchair was developed that can effectively be propelled with one arm while remaining maneuverable, lightweight, and foldable. An existing manual wheelchair was minimally modified and fitted with powerassisted components that could alternatively be attached to a wide range of manual wheelchairs. The design implements a motor and gear train to power the wheel on the user’s affected side, encoders on both rear wheels to track wheel position, and a heel interface on the footrest to control steering. A controls program was developed that analyzes wheel position and steering to respond to the motion of the hand-driven wheel. Extensive testing was performed to ensure design integrity. Testing results showed that the prototype successfully met and exceeded predetermined design specifications based on industry standard testing procedures. The design has the potential to deliver increased freedom to a considerable consumer base.

To keep up with technological as well as logistical challenges of the modern automobile market, major car manufacturing firms have resorted to virtual simulation tools. This enables the development as well as validation of vehicular models much before resources are invested into a new physical prototype.This project focuses on the development of a tool that would help in optimising the handling parameters of a vehicle. This is achieved by creating an optimization routine for tuning the various parameters of the Electronic Power Steering (EPAS). This process is usually done manually, by on-track testing, due to the difficulties in correlating Subjective Assessments (SA) with Objective Metrics (OM). Automating this process would help to reduce the overall research and development time, by providing a baseline tune for the EPAS parameters which could then be finely tweaked by manual track testing.The tool is built by interfacing various software in a multi-objective optimisation environment known as ModeFrontier. The modelling and simulations are performed in IPG CarMaker, with the post processing of the results taken care of by Sympathy for Data. Multiple optimization algorithms were tested to achieve the best optimisation routine. The EPAS parameters, namely the Basic Steering Torque, Active Return and Active Damping, act as the input to the optimization routine. The outputs of the model are the Objective Metrics, which provide a clear indication of the dynamic performance of a component. These metrics are optimized to _t the Steering DNA structure, which uniquely describes the attributes of a vehicle. The final optimised vehicle is manually tested at the track, to determine the real driving feel. / För att upprätthålla ett positivt momentum i såväl tekniska som logistiska utmaningar på dagens bilmarknad har stora biltillverkare börjat använda sig av virtuella simuleringsverktyg. Dessa verktyg möjliggör utveckling av diverse fordonsmodeller långt innan resurser investeras i en fysisk prototyp. Detta projekt fokuserar på utvecklingen av ett verktyg som potentiellt kan hjälpa att optimera dynamiska beteendeparametrar för ett fordon. Detta uppnås genom att skapa en optimeringsrutin för att ställa in de olika parametrarna för den elektroniska servostyrningen (EPAS). Denna process görs vanligtvis manuellt, genom test på provbana, på grund avsvårigheterna att korrelera subjektiva bedömningar (SA) med objektiva mätetal (OM). Att automatisera denna process kan bidra till att minska den övergripande forsknings- och utvecklingstiden genom att tillhandahålla en baslinje för EPAS-parametrarna som i efterhand kan finjusteras genom manuell justering på provbana. Verktyget är byggt genom att ansluta olika program i en optimeringsmiljö som kallas ModeFrontier. Modellering och simuleringar utförs i IPG CarMaker, med efterbehandling av resultaten i Sympathy for Data. Flera optimeringsalgoritmer testades för att uppnå bästa optimeringsrutinen. EPAS-parametrarna består av det grundläggande styrmomentet, aktiv retur och aktiv dämpning, och fungerar som invärden till optimeringsrutinen där utvärdera från modellen är objektiva mätetalen, vilket ger en tydlig indikation på den dynamiska prestandan hos en komponent. Dessa mätvärden optimeras för att passa Steering DNA-strukturen, som unikt beskriver egenskaperna hos ett fordon. Det slutliga optimerade fordonet testas manuellt på provbana för att bestämma den verkliga körkänslan.

Future heavy duty vehicles will be designed and manufactured with improved Advanced Driver Assistance Systems, ADAS. When developing ADAS, an accurate model of the vehicle dynamics greatly simplifies the development process. One element integral to the vehicle lateral dynamics and development of ADAS is the steering system. This thesis aims to develop an accurate model of a heavy duty vehicle steering system suitable for simulations. The input to the system is an input torque at the steering wheel and the output is the wheel angle. Physical models of the system components are developed using bond graphs and known relations. Some components are modelled with non-linear inefficiencies and friction of different complexity. Unknown parameters and functions are identified from measurement data using system identification tools such as, for example, linear regression and non-linear grid search. The different subsystems are identified separately to the extent deemed possible. Different model designs are considered, validated, and compared. The advantages and disadvantages of different model choices are discussed. Finally, a non-linear state space model is selected for its high accuracy and efficiency. As this final model can be used to simulate a heavy duty vehicle steering system on a desktop computer faster than real time, it fulfills its purpose.