An improved departed domain control strategy for acrobot

We propose an improved strategy for control of underactuated two-link manipulator named acrobots. Initial conditions of nonlinear systems determine its trajectory even under same control law, so we introduce a firing control law to change initial conditions, which leads a better performance. The motion space is divided into three areas: firing, swing-up and attractive; control laws for each are designed. For swing-up area, a control law based on a weak-control Lyapunov function(WCLF) is employed to increase the energy and control the posture of the actuated link For attractive area, a control law based on poles placement is designed. Stability is guaranteed in the swing-up area by the use of a WCLF based on LaSalle's invariance principle. Finally, an example is used to compare with previous results.