QLabs Virtual Ball and Beam

The 2 DOF Inverted Pendulum module consists of an instrumented 2 DOF joint to which a 12-inch rod is mounted. The rod is free to swing about two orthogonal axes. The module is attached to two Rotary Servo Base Units. Their servomotors’ output shafts are coupled through a four-bar linkage, i.e., 2 DOF Robot module, resulting in a planar manipulator robot. The 2 DOF Joint is attached to the end effector of the robot arms. The goal of the 2 DOF Inverted Pendulum experiment is to command the position of the 2 DOF Robot end effector to balance the pendulum. By measuring the deviations of the vertical pendulum, a controller can be used to rotate the servos, so that the position of the end effector balances the pendulum.

The Double Inverted Pendulum module is composed of a rotary arm that attaches to the Rotary Servo Base Unit, a short 7-inch bottom blue rod, an encoder hinge, and the top 12-inch blue rod. The balance control computes a voltage based on the angle measurements from the encoders. This control voltage signal is amplified and applied to the Servo motor. The rotary arm moves accordingly to balance the two links and the process repeats itself.