Design Optimization Of The Underactuated Multi-Fingered Dextrous Hand

Along with the rapid development of science and technology, robot technology has been applied to all aspects of human social life and production. Into the21st century, robotics in space and deep-sea detection, nuclear technology, biochemical experiments, medical services, fire mitigation, oil and gas development and other extreme environmental and precision fields has been widely used, has played an irreplaceable role, to rid humanity of the poor and dangerous work environment, and can be able to complete the works of precision and detection which the humans can not complete. That is widening the sphere of human activity. Multi-fingered robot hand, especially humanoid multi-fingered robot hand, has a very important role and significance as the end-effector of the robot which interacts with the external environment. Humanoid multi-fingered robot hand can not only be used as a general-purpose operating equipment used in various fields, but also can be used as disabled prosthetic. So it has a significant social value. However, multi-fingered dexterous hand with anthropomorphic features for the full drive, can be able to complete part of grasping and operational tasks. But its control complexity and high cost greatly limits its practical application as possible. In recent years, an ideal robotic hands solution based on the requirements in the theory of low-cost and easy-operation have been quickly popular. This kind of multi-fingered hands is characterized with a strong ability to grasp, stable performance, less actuators, brief control system and low cost. Because of such multi-fingered hands, leading to the practical application of the road is found.So the design of the hand in this article is based on the solution. It applies underactuated factors to the structure and motion mechanism of humanoid multi-fingered dexterous hand. Then a single tendon elastic underactuated mult1-fingered hand is designed which is with the characters of a simple structure, light weight, simple control, low-cost. The underactuated multi-fingered hand is with passive supple characteristics. That is, when grasping, it is adaptive to objects of different shapes. The hand can perform powerful enveloping ability and reconfiguration ability in grasp.In this thesis, in-depth analysis of this humanoid single tendon elastic underactuated multi-fingered hand’s structure, movement and function has been proposed.First, from the perspective of bionics design, the analysis of the human hand’s structure and functional characteristics has been proposed. It provides the design parameters for reference to the design of the underactuated hand. Based on that, the structural design of index finger, middle finger, ring finger, the thumb and the palm has been proposed.Secondly, according to the design of multi-fingered hand mechanism model, about its kinematics modeling, its forward kinematics equations have been pushed out. Analyzing static configuration of the hand under no-load conditions gets the equations about each joint angle and the tendon tension and the finger static configuration space along with variation of tendon tension. Analyzing the feature of the finger movement, a method is proposed to analysis the motion of the elastic underactuated multi-fingered hand. When grasping, statics is analyzed to get the expression of finger contact force.Again, optimized design about the structure of the size and layout of the pulley position has been proposed. A method for selecting the optimum joint spring stiffness through the joint workspace of the hand is proposed. Under the condition of the contact friction, the reason that Ejection phenomenon happens has been found. Determine whether the elastic underactuated finger has ejection phenomenon or not.Finally, a lot of grasping experiments have been made in order to verify the feasibility of actually grasping objects.