The Kinematics Model And Grasp Planning Of Bio-Soft-Manipulator

As a subdiscipline of the soft robotics,soft manipulators are rapidly developing and have received extensive attention and research with their advantages of active and passive applicability,safety and adaptability to complex environments.In recent years,there has been a great deal of achievement on the research of soft manipulators.At present,the research of soft manipulators is still in its infancy.There are still many challenges in terms of flexible materials,bionic structures,inverse kinematics,and grasping planning.Therefore,it is sufficiently significant to do the relevant research.The main purpose of this paper is to provide a more reliable and concise theoretically mathematical model for the fingers and the whole soft hand when the soft manipulator is used to grasp and capture objects.The content of this paper is as follows:(1)Imitating the physiological structure of octopus brachiopods,we designed two kinds of bionic soft fingers with adjustable stiffness were designed and manufactured.One was a three-chamber driven finger that could bend in any direction,the other was a two-chamber driven finger that could bend in only one direction.Based on the structure of the bionic soft finger,the static model of soft finger was established.Then the influence of the pressure on the static characteristics of soft finger was simulated.Otherwise,tensile tests and static model tests of rubber specimens were carried out to verify the correctness of the static model.(2)According to the simplified model and the bending geometry of the spring,the mapping relationship between the spring model elongation and the soft finger bending geometry parameters(bending direction,bending angle,bending radius)was established.Based on this,the relationship between input pressure and the distribution of the tip of the softfinger and the gesture of the finger was established.In addition,an inverse kinematics model of the soft finger was established,the required input pressure of each chamber for specifying the end point or posture of the finger.Furthermore,the analysis showed that the contact type between the soft finger and the object was soft contact,and then the gripping planning algorithm under the condition of this contact type was established.(3)Finally,the experimental platform for bionic soft manipulator was built.And the two types of fingers were carried out single-cavity bending experiment,multi-cavity coupling bending experiment and the grasping experiment respectively.The actual results were consistent with the theoretical model,which verified the effectiveness and accuracy of bending,working range and inverse kinematics.In this paper,a concise numerical analysis method was proposed,which was suitable for analyzing the bending,working range,pose and inverse kinematics model of soft finger.