Trajectory Planning for Overhead Crane With Double Spherical Pendulum and Varying Cable Length Effect
Due to the multi-input multi-output and underactuated dynamic characteristics,the overhead crane with double spherical pendulum and varying cable length effect still lacks efficient control approaches.During the simul-taneous operation of trolley moving,bridge moving and payload hoisting/lowing,the double spherical pendulum of hook and payload is more complex,and the nonlinear coupling characteristics of various state variables are stronger.It makes anti-swing control of overhead crane much more challenging.Moreover,the existing control methods can-not guarantee the desired transient control performance of the overhead crane system.To address the abovemen-tioned issues,this paper proposes a novel polynomial-based optimal trajectory planning approach.Firstly,an accur-ate dynamic model for seven degree-of-freedom(7-DOF)overhead crane with double spherical pendulum and vary-ing cable length effects is established by Lagrangian method without any simplifications.Based on this,a group of auxiliary signals containing various states are constructed.Then,the constraints imposed on the trolley/bridge mov-ing,cable length varying,hook/payload swing are equivalently transformed to some new constraints on the auxili-ary signals.Therefore,the trajectory planning problem of the overhead crane is transformed into a time optimiza-tion problem related to the auxiliary signals and solved by using the bisection method.The proposed trajectory planner not only makes transportation time as short as possible,but also ensures that full-states constraints are sat-isfied.At last,the simulation results prove the accuracy of the dynamic model and the effectiveness of the traject-ory planning method.
Underactuated cranemulti-input multi-output systemtrajectory planninganti-swing control