Kinematic Stability Analysis Of Multi-Robot Coordinated Towing System With Floating Base

Building a maritime power is a major deployment for our country,which is of great significance in promoting the healthy development of national economy.The development of Marine economy requires advanced offshore engineering equipment.Multi-robot coordinated towing system with floating base composed of several modular and small-load floating crane robots is proposed.The system has the advantages of reconfigurability,flexibility and universality.It can solve the problems of small load capacity,low efficiency and small scope of operation in Marine engineering operations such as offshore construction,seabed salvage and salvage.However,the complexity and uncertainty of the floating base multi-machine coordinated crane system have security risks in reality,so it is of great theoretical and practical value to study it.The spatial configuration of multi-robot coordinated towing system with floating base is determined firstly.Combined with the spatial configuration of the system,the kinematic model of the floating base,the folding arm crane and the towing system is established by coordinate transformation method.Combined with an example,the kinematics of multi-robot coordinated towing system with floating base is simulated numerically.The dynamic equation of floating base is established according to the rigid body dynamics.Newton-Euler equation is used to establish the dynamics model of the folding arm crane.Taking the first joint of the folding arm crane as an example,the joint force and the joint torque of each joint of the folding arm crane is deduced.The dynamic models based on the spinor balance equation and Lagrange equation of the towing system are established.Combined with the kinematics and dynamics models of each component,the whole dynamics of the system is discussed.The virtual prototype of multi-robot coordinated towing system with floating base is established by using ADAMS software.With the help of ADAMS/Cable module,the rope model is constructed.Combined with the actual working conditions of the lifting operation,the path planning of the load is carried out according to the lifting task,and the feasibility of the virtual prototype of multi-robot coordinated towing system with floating base is verified.By setting the driver function,the dynamic response characteristics of load swing and rope dynamic tension are simulated and analyzed,which is under the influence of swing motion of the base,lifting speed of the rope,rotation speed of the joint,initial length of the rope.The simulation results provide some reference value for the stability analysis and anti-swing control of the system.The kinematic stability of multi-robot coordinated towing system with floating base is divided into the stability of base and the stability of load,and the stability problems are discussed respectively.Considering the characteristics of the real-time change of internal force in the process of operation,the Force-Angle stability criterion is used to analyze the problem of the stability of base.Through numerical simulation,the standard stability angles corresponding to the two groups of joint angle of the folding arm crane are obtained.The numerical range of the two groups of standard stability angles is reasonable,which verifies the effectiveness of the Force-Angle stability in solving the problem of the stability of base.Through the tension factor and the position factor are weighted and integrated,The stability margin of the load is discussed by means of the hybrid stability evaluation method.The results show that the stability of the central position of the workspace is always better than that of the edge position.With the increase of the weight coefficient of the position factor,and the stability margin of the load increases gradually,indicating that the position factor has a greater influence on the stability of load.