中枢模式发生器与足端轨迹的非线性映射  

Nonlinear mapping between central pattern generator and foot trajectory

作　　者：陈久朋 陈治帆 伞红军[1,2] 祖永斌 Chen Jiupeng;Chen Zhifan;San Hongjun;Zu Yongbin(Faculty of Mechanical and Electrical Engineering,Kunming University of Science and Technology,Kunming 650500,China;Key Laboratory of Advanced Equipment Intelligent Manufacturing Technology of Yunnan Province,Kunming 650500,China)

机构地区：[1]昆明理工大学机电工程学院,昆明650500 [2]云南省先进装备智能制造技术重点实验室,昆明650500

出　　处：《仪器仪表学报》2024年第4期258-271,共14页Chinese Journal of Scientific Instrument

基　　金：云南省科技厅基础研发计划青年基金项目(202301AU070059)资助。

摘　　要：控制的仿生性和行走的稳定性是四足机器人步态研究中重要的两个方面。为了提高四足机器人运动的稳定性,本文通过Hopf振荡器搭建了CPG模型,分别实现了多种步态及步态之间的转换。比较了基于CPG的步态控制方法和轨迹规划的步态规划方法在行走上的优劣性。为了同时利用CPG控制和轨迹规划的优点,提出采用神经网络将CPG控制曲线与足端轨迹逆运动学获得的驱动曲线进行非线性映射,使得四足机器人在控制上具备仿生特性,在足端接触上具备零冲击特性。仿真和实验结果表明,采用CPG的步态生成方法和轨迹规划方法四足机器人的行走速度理论行走速度80 mm/s相近,但采用CPG的步态生成方法四足机器人侧向位移在±10 mm以内且俯仰角在±1.5°之间,而采用轨迹规划的控制方法四足机器人侧向位移在±35 mm以内且俯仰角在±4°之间,可见两种控制方式对侧向偏移和俯仰运动的表现不一致。通过实验测量可知,机器人采用walk步态行走速度为18.57 mm/s,与理论行走速度20 mm/s接近,步态转换后以trot步态行走,行走速度为76.15 mm/s,与理论行走速度80 mm/s接近,少许误差可能是装配和行走过程打滑导致的。测量其侧向偏移程度可知,其侧向的偏移量左侧在15 mm内,右侧在25 mm内,其侧向偏移量均在合适的范围内,证明所提算法的有效性。The bionics of control and the stability of walking are two important aspects in the gait research of quadruped robots.In order to improve the stability of quadruped robot motion,this paper constructed a CPG model using a Hopf oscillator,which achieved various gaits and transitions between them.We compared the advantages and disadvantages of gait control methods based on CPG and gait planning methods based on trajectory planning in walking.In order to simultaneously utilize the advantages of CPG control and trajectory planning,a neural network is proposed to nonlinearly map the CPG control curve with the driving curve obtained from the inverse kinematics of the foot trajectory,so that the quadruped robot has biomimetic characteristics in control and zero impact characteristics in foot contact.The simulation and experimental results show that the theoretical walking speed of the quadruped robot using CPG gait generation method and trajectory planning method is similar to 80 mm/s.However,the lateral displacement of the quadruped robot using CPG gait generation method is within±10 mm and the pitch angle is between±1.5°,while the lateral displacement of the quadruped robot using trajectory planning control method is within±35 mm and the pitch angle is between±4°,It can be seen that the performance of the two control methods on lateral displacement and pitch motion is inconsistent.Through experimental measurements,it is known that the robot adopts a walk gait with a walking speed of 18.57 mm/s,which is close to the theoretical walking speed of 20 mm/s.After gait conversion,it walks in a trot gait with a walking speed of 76.15 mm/s,which is close to the theoretical walking speed of 80 mm/s.A small error may be caused by assembly and slipping during walking.By measuring its lateral displacement,it can be seen that the lateral displacement is within 15 mm on the left and 25 mm on the right,both of which are within an appropriate range,proving the effectiveness of the proposed algorithm.

关 键 词：四足机器人 CPG模型 足端轨迹 非线性映射 行走稳定性 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术] TH14[自动化与计算机技术—计算机科学与技术]