Research Of The Structure Design And Dynamic Model For A Novel Soft Modular Robot

The soft robots can mimic natural mollusks,such as octopus,trunk,earthworms and so on.It is made of soft material that can withstand large strain so it can change its shape and size in large range freely.Compared with the traditional rigid robot,the soft robot can be used in the field of reconnaissance,detection,rescue and medical treatment.There are many advantages: the soft robot has better environmental adaptability.It can cross with the obstacle through passive deformation,and it can be in different form and movement through the active deformation.The robot can pass through a gap smaller than its normal size to the space that traditional robots can't do by combination of active and passive deformation.And it can imitate the movement mode of animals in nature to adapt to the environment that human can't reach.The modular robots are characterized by their relative independence,interchangeability and versatility.Therefore,our research is focused on soft modular robot.According to the research status of software robots both at domestic and international and the analysis of the merits and demerits of the robots in the laboratory,a novel soft modular robot(NSMBot)is designed,which is inspired by the bionics and combined with the characteristics of bio-peristaltic movement.Shape memory alloy(SMA)is used as a steering actuator and then the modular robot has more flexibility.The steering mechanism can stretch or bend through the coordinated control of 4 SMA wire enables,robot can reach most of the position in the space.The modular robot has 3 DOFs,it can move flexible,and it has the compact structure the reliable docking mechanism.The connection and connection relations of the two modules are introduced,and the topological structure of the modules is presented.The results show that it can provide a basis for the motion planning of the NSMbot.Based on the segmented constant curvature method and reference of the D-H modeling method,a soft robotic D-H method and the SMA driving wire model are proposed.The kinematical model of the soft robot and described the relationship between joints and actuator are established.The simulation of linear motion and the steering motion for the modular robot is made based on Adams software.Compared with the advantages and disadvantages of various dynamic modeling methods,Kane's method is used to establish the dynamic model of the soft robot.Moreover,by means of the force analysis,the kinetic equation of the Kane and the dynamic balance of the module section are established.The Kelvin model is used to describe the viscoelasticity of the silica gel.Finally,the dynamic simulation of the modular robot is carried out based on Adams software.Finally,according to the different constraints of the interpolation points,the corresponding polynomials are selected to get the trajectory planning.Line trajectory planning algorithm and the concrete calculation steps are given by taking the concrete configuration as an example.