Biomimetic Motion Control Of A Robotic Rat

Due to ethical and psychological complexity,it is not easy for basic medical research to directly conduct laboratory research on patients with human diseases,and it is difficult to clearly explain the pathogenesis of psychosis and to screen for drugs.To solve this issue,the researchers introduced a new method of interaction experiment between robotic rat and laboratory rat,in order to establish an animal model of rat that simulates the characteristics of human diseases.However,the similarity and diversity of the existing robotic rat are poor,which can't meet the practical needs of behavioral interaction experiments.In order to overcome the above problems,on the one hand,this paper optimized a new type of robotic rat(WR-5M)with a closer morphological and kinetic performance to laboratory rat.A new inverse kinematics method of solving the pitch and yaw is proposed,and the biomimetic motion control of WR-5M is realized from the kinetic parameters.On the other hand,based on the model of motion similarity evaluation,WR-5M is proved to be able to achieve a high similarity of biomimetic motion.By high similarity and quantitative biomimetic motion control for WR-5M,it can achieve high-fidelity,rich and varied biomimetic behaviors.This will help WR-5M and laboratory rat to complete the interaction of efficient behavior,at the same time,it provides reference for the establishment and quantitative evaluation of animal models of human diseases.The main contents of this paper are as follows:First of all,the WR-5M mechanical structure and control circuit board are optimized and designed to make it more close to the laboratory rat in morphology and workspace.Based on a WR-5M inverse kinematics method that complies with the laws of laboratory rat motion,joint variables are calculated,with the rapid and stable control of articulated motors,WR-5M can simulate the action primaries of laboratory rat from the kinetic parameters: pitch and pitch motions.Then,four parameters,the maximum pitch angle(MPA)and the maximum reachable height(MRH),the maximum bendable angle(MBA)and the minimum bendable distance(MBD),are used as indexes to measure the locomotion performance of WR-5M and laboratory rat.The WR-5M two typical action primitives(pitch and yaw movement)were evaluated.The experiment show that WR-5M has the similar performance of pitch and yaw motion of laboratory rat.Finally,four key parameters of pitch angle,pitch height,yaw radius and yaw distance were selected as the quantitative indexes to measure the similarity of WR-5M and laboratory rat,and the evaluation model of the motion similarity between them is established.Based on the above WR-5M system platform,control method and action primitives planning,four typical behavioral processes of laboratory rat are simulated.According to the aforementioned model of motion similarity evaluation,the similarity of typical behaviors of WR-5M is obtained respectively 96.0%,99.1%,97.7% and98.0%.The results show that WR-5M can achieve a high similarity of quantitative and biomimetic motion control.This will facilitate behavioral interaction studies between robotic rat and laboratory rat,and will help establish and quantify animal model of human disease.