This thesis presents the theory, methodology and results of building, tuning and testing a prototype for controlling body roll movement. Body roll is a result of lateral acceleration that acts on a vehicle when turning and result in torque on the roll center of the vehicle. The objective of this thesis is, in collaboration with Freno Air AB [7], to build a prototype and, with the help of sensors and micro controllers, restrict the body roll to avoid roll over on a semi-trailer that the company builds. The control unit in this thesis includes two PID controllers that is vastly used today in many different applications. The control unit is fed with signals from two pressure sensors on each side of the prototype frame. The pressures are given by four syringes, two on each side that are connected to the pressure sensors. One PID has small gains of KP = 0.2, KD = 0.005 and KI = 0 to take care of smaller and slower variations of pressure difference and one PID with higher gains of KP = 1, KD = 1 and KI = 0 to take care of faster and bigger variations in pressure difference which in both of the cases the pressure difference translates to body roll. The pressures give is enough of information of the prototypes state to be able to control it with the help of a motion platform that is able to roll in opposite direction to equalize the pressures. The results for the two cases of slow roll and fast roll are promising with a fast response, few oscillations and overshoots, which makes the system fast and stable, two things that are opposites in the world of closed loop control. The experiment was performed in a stationary form with applied disturbances and actuated with a motion platform capable of roll rotation.