Magnetic Control of a Simple Pendulum with a Moving Pivot Point

The present study introduces a magnetic PD control technique for the case of a simple pendulum driven by a sinusoidal motion of its pivot. The results attained demonstrate a good control performance for all the excitation cases of pivot point motion considered. The motion of the mass of the pendulum is successfully attenuated even when the pivot excitation is at the natural frequency of the pendulum. Furthermore, a fixed desired position can be achieved with small error and no saturation of the actuation present at steady-state. The initial distance between the magnet and the mass that ensures an efficient motion control is derived analytically and is validated by numerical simulations. The magnetic control method proposed serves as promising foundation for a non-contact position control technique for offshore wind turbine installation purposes.