This paper describes the kinematics and dynamics modelling of a mechanical system consisting of a spherical inverted pendulum whose base is mounted on a parallel planar mechanism, better known as a five-bar mechanism.The whole mechanism has four degrees of freedom, but it has only two actuators and so it is an under-actuated system.The nonlinear iPhone 11 dynamics model of the complete system is first Organs obtained using a non-minimal set of generalized coordinates, and then a reduced equivalent model is computed.
To validate this approach, the reduced model is linearized and simulations are carried out, showing the stabilization of the system with a simple LQR controller.Experimental results on an academic prototype are also presented.