Research On The Design And Grasping Control Of A Reconfigurable Multi-fingered Dexterous Hand

With the rapid growth of modern industry,it requires more intelligent,sophisticated and adaptable grasping systems to improve the automation.The most commonly used smart grasping tool in industry is the grasping system composed of the mechanical arm and end effector.The dexterous hand can complete many kinds of operation tasks because of more degrees of freedom,higher degree of intelligence and stronger adaptability than general grippers.It has gradually become the development trend of robot end-effector.When a specific end-effector fails to accomplish a specified task,replacing the endeffector becomes a necessary choice.Reconfigurable robots have also become a research hotspot in the context of industrial automation,and its goal is to improve the adaptability of grasping systems to complex work scenarios.Therefore,it is very important for the development of modern grasping system to develop smarter end-effector and reconfigurable mechanism with superior performance.To meet the requirements of grasping and manipulating complex shape objects and the functional requirements of the end-effector in arm-hand grasping system,a reconfigurable,variable configuration and under-actuated three-fingered dexterous hand was designed.Support the automatic replacement of the end claws under different tasks.And the reliable grasping of objects with different shapes and sizes can be achieved by changing the configuration of multiple fingers..Two kinds of reconfigurable mechanisms based on memory alloy wire-spring combined driver and magnetic locking mechanism,and multi-fingered dexterous hand based on underactuated mechanism,were studied.Based on these studies,the reconfigurable multi-fingered dexterous hand system was designed.The designed multi-fingered dexterous hand consists of three rigid underactuated fingers with similar structures and variable configurations.The underactuated finger is composed of two-stage four-bar underactuated mechanism and double parallelogram mechanism.The movement of the mechanisms is realized.They are driven by a motor.The power is transmitted to the only active part through synchronous belt transmission and worm transmission.The deformable palm is composed of a deformable mechanism and a palm bracket.The deformable mechanism is installed in the upper part of the palm bracket and is driven by two stepping motors.The posture of two fingers with variable positions is changed by the two stepping motors through bevel gear transmission and cylindrical gear transmission.The lower part of the palm bracket holds the control part based on ARM control board and driving board.The memory alloy wire scheme reconfigurable mechanism includes memory alloy wire-spring combined driver and steel ball locking mechanism.The magnetic locking scheme reconfigurable mechanism includes power-loss suction device and mechanical locking part.Both of them use similar control system control.The kinematics of the multi-fingered dexterous hand was derived and its workspace was analyzed.According to the characteristics of underactuated multi-fingered dexterous hand,the grasping scheme of underactuated multi fingered dexterous hand was proposed.Aiming at the common problems of grasping system in industrial application,an impedance-based arm-hand grasping control strategy was proposed,which was verified by the joint simulation of Matlab and Adams.On the basis of the above work,the integration of reconfigurable multi-fingered dexterous hand prototype was completed.The motion of underactuated mechanism and the grasping performance of multi-fingered dexterous hand were verified by experiments.The feasibility of the grasping scheme of underactuated multi-fingered dexterous hand was verified,and the functions and performances of the two reconfigurable mechanisms were verified.Experiments showed that the reconfigurable multi fingered dexterous hand achieved the design requirements.