Design And Performance Analysis Of Multimode Underactuated Manipulator Claw

With the development of robot end-effector,the current execution tasks and working environment of robots become more and more sophisticated and complicated.General robots and their end-holding devices have been far from reaching the requirements of aerospace operations,deep-sea operations,nuclear industry technology and flexible production lines that require a variety of dexterity and fine operation.In the intelligent storage automatic production line,there are a lot of tasks that need to be carried out to grab and select materials.The operation object is irregular in shape and has a large size range.The traditional manipulator claw is difficult to grab,and the stability cannot be guaranteed.At present,there are still some difficulties to complete the grasping of materials with different shapes.This paper focuses on the structural design,optimization design and grasping planning of the underactuated manipulator claw to carry out systematic and in-depth research.The main research work is as follows:(1)A new underactuated manipulator claw is designed.The main body is driven by connecting rod,which inherits the characteristics of connecting rod drive.Based on the regenerative design rules,the underactuated mechanism is obtained as the executive part.The claw has two grasping modes,which can not only adaptive grasp based on the shape of the object envelope,but also can steadily and accurately pinch a variety of different shapes of objects.(2)The jaw coordinate system of the underactuated manipulator is established,and the kinematics of the manipulator is analyzed.The trajectory of the finger,the speed and displacement of the fingertip and middle finger are analyzed,and the kinematic model was established.Then,the statics of the underactuated manipulator under precise pinching and enveloping grasping modes are analyzed.The contact force is analyzed and the contact force model is established.(3)The rod length parameters and structure are optimized.Based on the kinematic and mechanical models established above,the genetic algorithm and one-dimensional search method are used to optimize the rod length parameters,and a better parameter of the finger length of the underactuated manipulator is obtained.Under the condition that the length of the rod is unchanged,the lightweight and load-bearing capacity of the hand claw are optimized.The finite element static strength analysis of the hand claw is carried out,and the stress and strain of the hand claw after rod length parameter optimization and lightweight optimization are compared.The analysis shows that the structure of the hand claw after rod length parameter optimization and lightweight optimization is more reasonable.(4)The realization and transformation of two grasping modes(envelope grasping and precise pinching)of the underdriven manipulator claw are analyzed.The grasping spinor space of the underdriven manipulator claw is used as the grasping analysis index to evaluate the grasping quality of envelope grasping and precise pinching,and to guide the selection of grasping modes in the grasping planning.The grasping logic of the underdriven manipulator claw is obtained.The simulation test of the underdrive manipulator claw grasp,kinematic analysis and dynamics analysis by Adams,analysis of the movement law of each joint of the underdrive manipulator claw and the grasp contact force of the underdrive manipulator claw envelope grasp and precise pinch mode,verify the rationality of the underdrive manipulator claw structure.