Analysis And Design Of Under-actuated Manipulator Based On Metamorphic Principle

With the development of society and the progress of science and technology,the robot technology,as an important branch of high-tech,has attracted the attention of all countries in the world,and it has been greatly developed and widely used in many fields,such as industrial production,space and marine exploration,national defense construction and people’s lives.Robots’ working environment and task execution are becoming more and more sophisticated and complex,and people expect to be able to assemble a general,intelligent end-effector which can also meet needs of various complex tasks with the robot to complete various complex and delicate tasks.In this context,the research of robots’ multi-fingered dexterous hands has become one of the hot research directions in the field of the robot research.In the research and application of the traditional multi-fingered manipulator,the method of connecting several joints in series is generally used to construct the finger of the manipulator,and a drive and a sensor are set for each degree of freedom,which leads to excessive driving elements and complex control,reduces the flexibility and controllability of the manipulator,and increases the development cost of the manipulator at the same time.Aiming at this problem,the under-actuated mechanism based on the principle of metamorphism is a new way to design the manipulator,and has been paid close attention to.The manipulator designed with the principle of under-actuation can not only simplify the control strategy of the manipulator effectively,but also has the advantages of simple structure and easy manufacture.On the basis of consulting the research status of the multi-fingered manipulator,metamorphic theory and under-actuated principle at home and abroad,a kind of clamping mechanism with simple structure,few actuating elements and wide application scope is developed,that is,a kind of manipulator which completes to grasp objects based on the metamorphic principle and under-actuated principle.The main contents of this paper include the structural design of the under-actuated manipulator based on the metamorphic principle,three-dimensional modeling of the mechanical structure,configuration transformation analysis,random configuration analysis,static analysis,shock kinematics analysis,impact dynamics analysis,virtual prototype simulation analysis,prototype production and experimental research,The work of this paper is as follows:(1)The structural design and configuration analysis of the under-actuated manipulator based on the metamorphic principle are carried out.Based on the analysis of the topology diagram,correlation matrix and adjacency matrix,a new under-actuated manipulator mechanism is designed according to the metamorphic theory.The working principle and configuration of the mechanism are described in detail,and the manipulator is designed in detail by using 3D modeling software UG.(2)The configuration transformation analysis and static analysis of the under-actuated manipulator based on the metamorphic principle are carried out.By introducing the concept of equivalent resistance gradient,the static analysis of under-actuated manipulators in the different configuration is carried out.At the same time,the reason of random configuration of metamorphic mechanism in the process of configuration transformation is clarified,and the randomness of configuration is analyzed by using the equivalent resistance gradient model when different parameters are changed.(3)The kinematic analysis of the under-actuated manipulator based on the metamorphic principle is carried out.When the manipulator grasps the object,the detailed kinematics equation is established,the position,speed and acceleration are analyzed,and the vibration and impact performance of the manipulator finger in the process of configuration transformation and transformation are analyzed,the maximum vibration and impact characteristic parameters are calculated,and then the stable grasping performance of the manipulator is evaluated.(4)The dynamic analysis of the under-actuated manipulator based on the metamorphic principle is carried out.The Lagrange method is used to establish the dynamic equation of the mechanism,and the generalized kinematic coordinate system is built,and the gravitational potential energy and kinetic energy of the mechanism are calculated.At the same time,the impact dynamic equation of the mechanism is established,and the simulation of impact vibration of the metamorphic mechanism carried out in the software MATLAB,and then the relevant characteristic curves are obtained,so as to optimize the grasping performance of the manipulator.(5)The virtual prototype of the under-actuated manipulator based on the metamorphic principle is simulated and analyzed.By using the multi-body dynamics analysis software ADAMS,the grasping process of the under-actuated manipulator with four different configurations based on the metamorphic principle is simulated and analyzed.The simulation results show that there are different degrees of impact vibration in the process of grasping,and there are also different degrees of vibration after impact.At the same time,by obtaining relevant kinematic and dynamic parameter curves,the reasonability of the mechanism design is proved.(6)The prototype and experimental research of the manipulator are carried out.The prototype of the manipulator is manufactured by 3D printing,and then a simple grasping experiment is carried out to verify the reasonability and feasibility of the under-actuated manipulator designed based on the metamorphic principle,and it has stable grasping ability and excellent self-adaptability.