This example shows a fairground carousel ride. A torque applied to the wheel causes the carousel to rotate and a hydraulic actuator provides the force to lift the arm. The cabs are free to rotate about an axis approximately tangential to the wheel radius. When the wheel is near vertical, the centrifugal acceleration acting on the cabs (caused by the rotation of the wheel) ensures that the cabs are close to a near vertical position. Consequently, the riders are close to 'up-side-down' at the top of the rotation.
The acceleration at the center of the torso of a dummy is measured to show whether the ride is 'fun' and 'safe'. In addition, the hub motor power and hydraulic pressure are measured to validate the design. The control signals (reference and actual) for the hub speed and lift-arm angle are plotted to show the performance of the controllers.