Dynamics-based Trajectory Planning And Tracking Control For Cooperative Multiple Cranes

With the large-scale,heavy-loading of the objects being lifted and the diversification of the requirements of the lifting environment,people have put forward higher requirements for crane equipment.The working ability of single crane is limited.In order to meet the engineering needs of hoisting heavy-duty large-scale loads in a complex working environment,multiple cranes collaborative work becomes a practicable solution.However,relying on manual experience can not meet the requirements of safety and reliability,and is prone to major chain accidents.Therefore,researches on problems of multiple cranes collaborative operation control have very important theoretical and engineering practical significance.The dynamics model is the basis for studying the problem of multi-crane collaborative operation control.In this paper,the mechanical analysis of multi-crane system is decoupled into two parts for the characteristics of crane cooperative operation.Firstly,the six-degree-of-freedom dynamics model is established by Lagrangian method for the payload in the system.For every single crane in the system,the inverse crane dynamics analysis of the individual crane motion law and drive is performed with known payload motion and sling tension.Then,according to the dynamic model of payload,the symplecitc optimal control algorithm is applied,and the minimum energy consumption is used as the objective function.The constraints of crane wire rope ultimate tension,payload moving speed,attitude angle change range,avoidance obstacles and other safety related to crane safety are considered.Solve the optimal motion mode and required control force of the payload from the specified starting point quiescent state to the specified end point quiescent state and can avoid obstacles.According to the optimal control solution combined with the inverse dynamics to solve the motion law of the multiple cranes system and the power that needs to be provided.The simulation model of multiple cranes cooperative lifting is established by using ADAMS software to verify the correctness of the dynamic equation and the optimal control algorithm.Artificially set a trajectory that satisfies the initial and the end state and the obstacle avoidance requirements,and designs different motion speeds.The least squares method is used to obtain the power of the payload under artificially set motion law,and compared with the optimal control power,the energy saving effectiveness of this method is verified.Finally,the symplecitc pseudospectral predictive control algorithm is applied to perform closed-loop control.Using the open-loop optimal control trajectory obtained above as the desired trajectory,the trajectory tracking control problem of multiple cranes under the condition of multiple initial state disturbances and multiple process disturbances is studied.By improving the parameter design of the state variable weight matrix,the robustness of the model predictive control algorithm under initial condition changes and external disturbances is improved.