|dc.description.abstract||Waves cause problems when operating in big sea because of their constant movement. Many operations, as
moving cargo from ship to ship or from ship to a fixed platform, demands stable working conditions, and
this is often difficult to achieve when the waves becomes too big.
The use of active heave compensation can greatly reduce this disturbance. To overcome the movement of
the waves, different applications can be applied. The 6 degrees of freedom Stewart platform can be used to
compensate, as it can compensate for all motions, translative and orientational. It can also be used as a test
platform to create artificial waves/movements which can be used to test/develope new heave compensating
By solving the kinematics for both the Stewart platform and the hydraulic manipulator, creating a dynamic
model for the manipulator using simulation software, the machines are analyzed.
They are modeled and simulated in different software as SimulationX and MATLAB/Simulink. A model of
a hydraulic manipulator is created to compensate wave motion when we place the manipulator on top of the
Stewart platform. The manipulators has a redundant configuration and the properties of this is explore in
regards to heave compensation.
A physical experiments shows that the end effector of the hydraulic manipulator follows a straight line as if
it heave compensating.
In order to detect changes in position and orientations, an Inertial Measurement Unit is designed. This can
detect fast angles changes in roll and pitch due to sensor fusion using an accelerometer and a gyroscope. A
solution for removing position drifting by introducing a Spring-Damper-System is also presented. Further
research concerning wave prediction may increase the accuracy of measuring position using the accelerometer.
By creating these models and test them in real life, we will have a great tool for further research concerning
heave compensation. Our new simulation of compensation indicates that many different applications for
wave compensation can be developed and tested using the Stewart platform, which gives a real life testing
environment. By having this complete heave compensation laboratory many new ideas and product can be