부산대학교 도서관

This paper presents a position control strategy for a planar active-passive-active (APA) underactuatedmanipulator with second-order nonholonomic characteristics. According to the structural characteristics of the planar APA system, we divide the system into two parts: a planar virtual Pendubot (PVP) and a planar virtual Acrobot(PVA). For the PVP, we mainly fulfill the target angle of the first link, which is calculated through the geometrymethod, and make the system stable. In this stage, via keeping the states of the third link being zero, the system isreduced to the PVP. Meanwhile, we design an open-loop control law based on the nilpotent approximation (NA)model of the PVP to make the second link stable and the first link stabilize at its target angle. Then, the planar APAsystem is reduced to a PVA with all links’ angular velocities being zero. For the PVA, we mainly realize the othertwo links’ target angles obtained via the particle swarm optimization (PSO) algorithm. Thus, the control objectiveof the planar APA system is achieved. Finally, above control strategy is verified by simulation results.