Design And Research Of Multi-degree-of-freedom Controllable Port Gantry Crane Mechanism

Gantry crane is widely used in port lifting and handling,mechanized loading and unloading,shipbuilding and other fields.Its development has evolved from the immutable fixed and rotatable boom crane to the gantry traveling mechanism,pitching boom and horizontal luffing system.The rotating mechanism is connected with the gantry through the large three-dimensional cylindrical bearing.Through the rotating system,the upper part of the crane can achieve 360 Degree rotation.The steel structure and cantilever beam of the hoisting actuator are driven by gear rack and screw and pulled by wire rope to adjust the pitch angle.The output of the flexible track has the disadvantages of small working range,inflexible operation and inflexible output.In addition,the traditional gantry crane’s lifting actuator is mostly plane single degree of freedom mechanism,which can only achieve a single action in the plane,which makes it difficult to output flexible working track during operation.In view of the above problems,a new type of controllable port gantry crane is designed and used as the research object to explore the controllable port gantry crane mechanism.The new gantry crane is characterized by the installation of drive motor on the rotating frame,the use of external auxiliary drive,light rod linkage,the mechanism has the advantages of small inertia,flexible movement track,sensitive movement,good dynamic performance,etc.,while avoiding the problems of stiffness difference,inertia,joint error accumulation caused by the installation of the serial manipulator drive device at the joints.The specific research contents are as follows:In order to verify the positive and inverse solution of the mechanism position,we use the closed-loop vector method to solve and substitute the given value for comparative analysis,and then solve and analyze the speed and acceleration of the port mechanism.In the port gantry crane kinematics analysis for the springboard,the force analysis of the mechanism of each rod,using Lagrange method to build a rigid body dynamics model,for the port gantry crane follow-up study how to select the motor provides a certain basis,but also for how to set up the port mechanism control system as a reference.On the basis of the dynamic static model,the paper analyzes the stress of key parts in the movement process of the port gantry crane with their position and posture changes.According to the dynamic calculation,the dynamic stiffness model of the port gantry crane is established by using the stiffness superposition method,and the change of the overall stiffness of the port gantry crane with the angle of the supporting boom and the angle of the lifting boom is analyzed The working path of portal crane and the improvement of working accuracy of portal crane provide some reference.Finally,the simulation software is used to model the components of the port mechanism.After the assembly is completed,the constraints are set for each pole and the simulation analysis is carried out.The motion law curves of the port gantry crane are obtained,which verifies the correctness of the kinematics and dynamics derivation of the port gantry crane.