A water jet is a propulsion system for vessels. The principle of water jet is to admit water into the hull, then add head to the water via the impeller and then let the water go through a guide vane package and then discharge it at the stern. The reaction force will bring the vessel into motion. KaMeWa Group, a Vickers company who manufactures water jet propulsion systems, initiated the work. This

The object of this thesis is to explore of a planar, almost circular amoeba, can move efficiently in an inviscid fluid. We investigate a homogenous amoeba and a heterogeneous amoeba and find that motion is possible for both using the physical fact that more work is needed when moving a bulky body in a fluid than when moving a small body of the same mass. For our calculations to be valid only small

Backlash is common in mechanical and hydraulic systems. It severely limits the overall system performance. Many mechanical solutions have been developed to overcome backlash, for example by using spring-loaded split gear assemblies or dual motor systems. These mechanical solutions can satisfactorily handle the backlash problem but they give rise to other problems like decreased accuracy and reduce

Backlash is often present in mechanical transmission systems and can be one of the main causes that severely limits control systems performances. In this work are presented a number of adaptive algorithms that through a proper feedforward nonlinear action try to compensate the backlash. Due to the nonlinear nature of the problem, convergency proofs are very difficult; nevertheless simulations show

In order to analyse the human postural control system single-stimulus multi-response measurement experiments are made, where the body sway due to an induced disturbance on the calf muscles are recorded with force platforms, Selspot systems or EMG-equipments. The measured outputs are usually analysed one by one as for a Single-Input Single-Output system. In this study a Single-Input Multi-Output ap

Industrial robots are used/configured/programmed by several different types of users/programmers. The control system should preferably expose a uniform view for each programming situation. Such views were defined by the Open Robot Control (ORC) architecture, developed within the department in an earlier project. This project refines and evaluates some robot programming principles. First, earlier p

This paper describes three improvements for a PID controller. These improvements have been created with SattLine, which is an object-oriented, distributed process automation system developed by Alfa Laval. These improvements are a compensator for static friction in control valves, an interpolation between the PID values when the system is non linear and the creation of a table to save different