四足步行机器人步态规划及稳定性分析

以四足机器人为研究对象,详细地分析了四足步行机器人的步态和稳定性的运动关系,并在此基础上给出了四足步行机器人步态设计数据和步态图.为进一步研究机器人实用化提供了可靠的数据.     

四足机器人典型步态仿真

四足机器人相对于双足机器人在稳定性和承载能力上要好,而相对于六足和八足步行机器人在结构和控制上比较简单,因此四足步行机器人已经成为移动机器人领域研究的热点之一.文中运用SolidWorks、ADAMS和Mtalab/Simulink建立机器人仿真模型,并在仿真系统中对机器人进行平面直线行走步态的仿真研究,并对质心速度均匀和非均匀情况下的机器人运行效率、足尖地面碰撞力、单腿髋关节力进行了仿真与分析.经仿真验证:相对于质心速度非均匀步态,质心速度均匀的步态在机器人运行稳定性和运行效率方面均得到很大的提高,而对足尖碰撞力和单腿髋关节力影响较小.     

一种四足马机器人的结构模型及其步行控制

参照马的生理结构,对四足马机器人的一种结构及其步行控制方法进行了研究。为验证该方法的有效性,首先,根据仿生原理设计出具有12个运动关节和4个球形脚部的四足马机器人结构模型,并求出了其运动学反解;其次,基于提出的结构模型,设计并实现了四足马机器人行走步态和对角小跑步态,并对步行稳定性进行了分析。步行实验表明,所提出的四足马机器人仿生结构及两种步态的实现方法具有可行性。     

四足步行机器人稳定性分析

基于四足步行机器人仿真模型对机器人的瞬时质心坐标进行了计算,获得了四足步行机器人直行步态下瞬时质心的运动规律,分析了各质量模块对机器人质心坐标的动态影响,对比了瞬时质心位移与几何中心位移的相对关系。给出了四足步行机器人静步态稳定性判定的公式,计算了基于瞬时质心的稳定裕度,对比分析了基于瞬时质心和基于几何中心的稳定裕度,提出基于几何中心的稳定裕度计算可以减少计算量,提高响应特性,适合实时静步态控制情况下应用,基于瞬时质心的稳定裕度可以得到稳定裕度的精确值。     

四足爬行机器人步态分析与运动控制

为了实现液压作动的四足步行机器人的稳定行走,根据运动稳定裕量原则规划四足机器人的直行步态,保证三足支撑机体时稳定裕量为100 mm;针对液压缸运动加速度突变导致机体冲击振动的问题,提出了利用S型曲线作为各自由度的运动位移控制规律的方法。按照JQRI00型四足步行机器人原理样机的结构建立了虚拟样机模型,应用仿真软件对所设计步态进行了仿真,分析了步态的运动学、动力学特征和位移控制方法的运动特征;在四足步行机器人原理样机上进行了试验,并将试验与仿真结果进行了比较。研究结果表明,所设计的机器人步态可行,保证了机器人具有较好的行走稳定性;将S型曲线用于位移控制,消除了液压缸运动加速度的突变,进一步提高了机体运行的平稳性。     

四足步行机器人腿机构及其稳定性步态控制

结合实际 ,详细地分析了四足步行机器人的步态和腿机构的运动关系 ,并在此基础上给出了四足步行机器人腿部机构和驱动控制方案。     

四足步行机器人稳定性分析

基于四足步行机器人模型对机器人的瞬时质心坐标进行了计算,得出了瞬时质心的运动规律,分析了各质量模块对机器人质心坐标的影响,对比了瞬时质心位移与几何中心位移的相对关系。给出了四足步行机器人静步态稳定性判定的公式,计算了基于瞬时质心的稳定裕度,并对稳定裕度进行了对比分析。     

类人猿型机器人前向四足步行的研究

类人猿机器人是一种具有多种移动方式的新型机器人。同常规的四足步行机器人相比,该机器人的结构具有特殊性和复杂性。为了实现拥有这种结构机器人的前向四足步行,我们提出了新的步态、轨迹规划、稳定平衡判据。仿真和实验结果证实了这些分析的合理性。     

慧鱼六足仿生机器人步态研究与实现

在仿生学原理的基础上,对六足步行机器人三角步态的行走原理和稳定性进行了分析。采用慧鱼仿生机器人包搭接出六足步行机器人,进行了一系列步行的实验。并对机器人腿部机构中的足端轨迹进行了仿真与分析。结果表明该机器人能够严格按三角步态进行行走,实现诸如直线、转弯、躲避障碍物等行走功能,具有较好的机动性。     

四足机器人轨迹规划及移动能耗分析

步行机器人移动能效率研究有重要意义。针对四足机器人对角小跑步态,对比分析了三种不同足端轨迹的移动能效率问题。将四足机器人的对角小跑步态周期分为摆动相和支撑相,采用D-H坐标法和反变换法进行了腿机构运动学正逆解分析。基于刚体动力学的质心运动定理分析足端接触模型,考虑动态步行中足端与地面间的接触,曲雅可比矩阵建立步行中足端接触力与关节驱动力矩的映射关系,并基于拉格朗日动力学建模法对四足机器人摆动相和支撑相分别进行动力学建模。规划了三种不同足端轨迹,分别为摆线函数、正弦函数和直线函数,对比分析了三种足端轨迹下的运动学和动力学特性。进行完整对角小跑步态周期的能量消耗分析,以移动能耗率为评价指标,对比分析三种足端轨迹的能量消耗,研究四足机器人步高、步距、关节起始角等步态参数对移动能量消耗的影响,为四足机器人的参数优化和轨迹规划提供理论依据。     

QW-Ⅰ型全方位四足步行机器人的设计及实验研究

本文介绍了QW-Ⅰ型四足步行机的设计特点及其层次式控制系统结构,着重研究了以规则步态实现全方位行走问题,提出通过侧行步态的切换及触地腿的局部调整来实现沿给定路线运动的方案。完成了样机研制,进行了实验研究。     

一种新型四足变胞爬行机器人的步态规划研究

随着移动机器人在探测救援中的应用逐渐增多,活动灵巧、环境适应能力强的多足机器人越来越受到国内外学者的关注。介绍一种腰部可以活动的四足机器人的设计及其步态生成,并展示了活动腰部可提升机器人对极端环境的适应性。提出三个基本假设以简化机构模型,提出腰部构态变换规则,并用几何方法说明了腰部构型变化可扩大机器人腿部活动空间,从而提升对复杂环境的适应性。另外,腰部运动与步态融合,生成了两种新的基本步态——扭腰直行步态和原地旋转步态。基于提出的两种步态,对比了固定腰部与可动腰部条件下运动稳定裕度的变化,分别计算了狭窄弯道通过条件,并分析了所设计步态对头部视觉的影响,从而证明所设计机器人具有较高的极端环境适应能力。     

Gait Planning for a Quadruped Robot with One Faulty Actuator

Fault tolerance is essential for quadruped robots when they work in remote areas or hazardous environments. Many fault-tolerant gaits planning method proposed in the past decade constrained more degrees of freedom(DOFs) of a robot than necessary. Thus a novel method to realize the fault-tolerant walking is proposed. The mobility of the robot is analyzed first by using the screw theory. The result shows that the translation of the center of body(Co B) can be kept with one faulty actuator if the rotations of the body are controlled. Thus the DOFs of the robot body are divided into two parts: the translation of the Co B and the rotation of the body. The kinematic model of the whole robot is built, the algorithm is developed to actively control the body orientations at the velocity level so that the planned Co B trajectory can be realized in spite of the constraint of the faulty actuator. This gait has a similar generation sequence with the normal gait and can be applied to the robot at any position. Simulations and experiments of the fault-tolerant gait with one faulty actuator are carried out. The Co B errors and the body rotation angles are measured. Comparing to the traditional fault-tolerant gait they can be reduced by at least 50%. A fault-tolerant gait planning algorithm is presented, which not only realizes the walking of a quadruped robot with a faulty actuator, but also efficiently improves the walking performances by taking full advantage of the remaining operational actuators according to the results of the simulations and experiments.     

Energy efficiency analysis of quadruped robot with trot gait and combined cycloid foot trajectory

Quadruped robots consume a lot of energy, which is one of the factors restricting their application. Energy efficiency is one of the key evaluating indicators for walking robots. The relationship between energy and elastic elements of walking robots have been studied, but different walking gait patterns and contact status have important influences on locomotion energy efficiency, and the energy efficiency considering the foot-end trajectory has not been reported. Therefore, the energy consumption and energy efficiency of quadruped robot with trot gait and combined cycloid foot trajectory are studied. The forward and inverse kinematics of quadruped robot is derived. The combined cycloid function is proposed to generate horizontal and vertical foot trajectory respectively, which can ensure the acceleration curve of the foot-end smoother and more successive, and reduce the contact force between feet and environment. Because of the variable topology mechanism characteristic of quadruped robot, the leg state is divided into three different phases which are swing phase, transition phase and stance phase during one trot gait cycle. The non-continuous variable constraint between feet and environment of quadruped robot is studied. The dynamic model of quadruped robot is derived considering the variable topology mechanism characteristic, the periodic contact and elastic elements of the robot. The total energy consumption of walking robot during one gait cycle is analyzed based on the dynamic model. The specific resistance is used to evaluate energy efficiency of quadruped robot. The calculation results show the relationships between specific resistance and gait parameters, which can be used to determine the reasonable gait parameters.     

Tripod gait-based turning gait of a six-legged walking robot

The turning gait planning and improvement methods of a six-legged walking robot on the basis of tripod gait are presented in this study. A projection method that considers an unstructured environment is proposed for the turning gait planning of the six-legged walking robot. The body and foot motion trajectories of the swing legs are planned with polynomial curves to keep the robot steady while walking. Two basic turning gaits, namely, circling and spinning gaits, are successfully designed with the planning method. An optimized method is proposed to improve the turning angle, which is subjected to stability, kinematics, and relief amplitude constraints in the unstructured environment. The turning ability of the turning gait is improved with the optimized turning angle. The circling and spinning gaits are implemented in simulations and experiments. Results demonstrate that the planning and improvement methods for the turning gait are valid and correct.

     

四足步行机器人步态规划与稳定性分析

通过对各种步态详细的分析和讨论,得出了稳定行走的最佳步态。为了得到稳定、易于控制的机器人系统,研究和分析了四足机器人的静态稳定性,并给出了系统稳定性的判断方法。     

Gait definition and successive gait-transition method based on energy consumption for a quadruped

In nature,to realize the smooth motion for different speeds,the continuous gait transition is usually required for the quadrupeds.Thus,the gait simulation of quadrupeds is a requisite step to obtain the stable and energy-efficient gait for the walking machines.In this paper,the definitions of the two gait parameters,phasic difference and duty factor are presented,which can determine the gait of the quadrupeds.Then,several typical gaits of the quadrupeds are analyzed such that the seven standard gaits and corresponding parameters are summarized.Additionally,the variance law of the two parameters,which determine the relationship of gait transition,is analyzed.Furthermore,the quadruped gait derivative spectrum (QGDS) is proposed and the gait definition of the quadrupeds is presented.To minimize the power consumption,the choice criterion of gait,the optimal gait in terms of the motion speed,duty factory,and power consumption for the walking machines,is developed.Last,the continuous variance of the gait is implemented by the simulation of the gait transition from walk to trot,which evaluate the choice criterion and transition of gait.     

复合运动模式四足机器人机构设计及分析

研制了一种轮足复合运动的四足智能移动机器人,该机器人可以步行前进,原地转弯,楼梯爬越,也可在良好路面利用足底轮以较高速度滚动前进。阐述了机器人的机械结构和参数,运动学分析和运动空间描述。利用ADAMS建立了三维仿真模型,进行了多种步态的仿真。得出稳定裕度合适的步态,实验验证了机器人的性能。