Variable structure control is applied to an underactuated two andthree-link robot. Control laws are developed to invert the robot from itsstable, downward equilibrium position to an inverted position. This maneuver isaccomplished by pumping energy into the system with the variable structurecontroller. A linear balancing controller is activated once the robot nears theinverted position. Numerical simulations are presented for both the two andthree-link robot.