In this master thesis, it will be shown howto estimate the unknown environmental forces acting on different vehicular and robotic systems. As force sensors are expensive, complex and not suitable to operate in hazardous environments, we present an approach to force estimation using model based observers. Only position measurements are assumed to be available and it will be shown how to use this force estimation to build an improved velocity observer. A force estimator able to follow ramp environmental forces is also introduced. We will pay special attention to stability issues and noise considerations. Simulations will be done using Matlab and Simulink. A parameter identification and force estimation experiment will be done using an industrial robot ABB irb2000
