The planar inverted pendulum series of products adopt an open architecture control solution and a modularized experiment platform. With XY table and 2-DOF robot arm module as the base platform, adding a 2-DOF ball joint, a one-stage or two-stage inverted pendulum is developed to provide a more challenging research and experiment platform. A planar inverted pendulum simulates more closely the control and visual effect of an inverted handstand of an acrobat or the launching position control of a missile or rocket.