Research On Lightweight Design Of Industrial Manipulator

As an important high-end intelligent manufacturing equipment,industrial robots have been widely used in various fields such as electronic and electrical,household appliances,machining,automotive,medical biology,aerospace,etc.The main structure of industrial robot is mechanical arm.However,problems such as bulky size,heavy structure and low load-to-weight ratio commonly exist in traditional industrial robotic arm,which severely limit the effective improvement of the performance of the whole machine.In view of this,this paper focuses on the lightweight design and structure optimization of the RB20 industrial robot mechanical arm based on multi-objective topology optimization and goal drive size optimization.The following studies were carried out:The dynamic analysis model of RB20 industrial robot is established,and the basic dynamic mathematical model and virtual prototype simulation model of the industrial robot are completed.Five different motion conditions are designed for the big arm and the small arm,and the final load information under this condition is taken as the instantaneous maximum load at a constant speed.The load information of the big arm and the small arm under these conditions is obtained.The static and modal analysis of the big arm,small arm and the whole machine are completed by using the load information of the dangerous condition under the above conditions.The results show that the stiffness,strength,natural frequency and vibration mode of the three materials are within a reasonable range,and the stresses are far less than the yield strength of the corresponding materials.Thus,the lightweight design can be carried out.Multi-objective topological optimization design of big arm and small arm was carried out.Aiming at static and dynamic stiffness,a comprehensive multi-objective function of flexibility and average frequency value is constructed by using compromise programming method,and the target topology optimization and model improvement of big arm and small arm are completed.The calculation results show that the big arm mass and the small arm mass are reduced by 10.43% and 13.22% respectively after topological optimization.The static and dynamic characteristics of both arms are improved,which verifies the effectiveness of the multi-objective topology optimization method.Based on the topological optimization,the dimensions of the new big arm and the new small arm are optimized by the goal driven dimension optimization method.Response surface method optimization is applied to optimize the parameters of the big arm,which further reduces the mass to 14.62% of the original arm.The quality of the small arm is reduced to 16.34% by direct optimization.As a result,the machine mass is reduced by 5.88 kg,and the static and dynamic performance of the mechanical arm and the load-dead weight ratio of the industrial robot are significantly improved.The validity of the optimization method combining multi-objective topology optimization and goal driven size optimization is proved.