双足机器人的动力学分析与仿真

根据对双足行走机器人的结构和步行步态的分析,将其简化为七连杆机构,并建立了运动学和动力学方程,在设定的双足机器人行走步态条件下,计算出其运动过程中各关节的运动轨迹及所需扭矩,并对其步行时步态的稳定性和各个关节扭矩进行了分析和比较,揭示了双足机器人行走时各关节所需扭矩之间的配比关系。     

七杆双足机器人行走系统动力学研究

针对双足步行机器人结构复杂性、系统非线性和动态步态难控制的问题,以七杆双足步行机器人为研究对象,建立七杆双足步行机器人动力学数学模型,模型描述出机器人在动态步行中从欠驱动相到完全驱动相的切换及步行中产生的冲击碰撞问题,体现了动态步行的非光滑动力学特性。借助仿真平台对研究对象各关节运动参数进行分析,结果反映出机器人模型在完整的周期步行过程能够稳定行走及发生碰撞时各运动参数的变化,验证了参数化模型的正确性。     

双足机器人并联踝关节优化设计

通过对人的踝关节运动机理分析,设计一种新型的双足机器人踝关节并联机构。建立并联机构的参数化模型,并对该模型进行运动学和动力学分析,得出该并联机构的一阶影响矩阵、伸缩运动的驱动力与零力矩点(Zero moment point, ZMP)轨迹关系。由于实际双足机器人行走时踝关节驱动力矩与角速度差异较大,为解决双足机器人步态行走中踝关节的动力学不平衡特性,结合并联机构的运动特点,迭代计算优化并联机构的结构参数,使踝关节两个驱动元件的驱动功率峰值和速度趋于一致。进行双足机器人步行试验研究,结果表明,优化后的并联结构踝关节的驱动功率峰值是串联结构下功率峰值的50 %左右,降低驱动元件的功率设计要求。在满足双足行走时踝关节的运动性能要求下选择小功率的驱动元件,有利于减小关节的体积和质量,减小能耗。     

仿生直立双足机器人的稳定性控制算法

仿生直立双足机器人共有7个旋转自由度,对其稳定性控制是保证双足机器人稳定行走和姿态变换的关键。传统方法中对仿生直立双足机器人的稳定性控制采用二自由度超外差控制方法,对直立双足机器人抓握和操控的运动规划效果不好。提出一种基于末端效应逆运动学分解的仿生直立双足机器人的稳定性控制算法,构建了仿生直立双足机器人运动学结构模型,采用末端效应逆运动学分解方法对机器人的运动学模型进行七自由度重构,在重构的运动学状态空间中实现仿生直立双足机器人稳定性控制,实现控制算法改进。仿真结果表明,采用该算法进行机器人稳定性控制,机器人行走过程中各个机构部件具有稳定运动学参量的输出,仿生双足机器人的控制机构参数仿真结果与理论值在一定的波动范围内相符,保证了机器人在行走和各种行为动作实施过程的姿态稳定性。     

两足步行椅机器人步行参数对稳定性的影响分析

两足步行椅机器人是一种替代轮椅或假肢、为残疾人服务的助残机器人。这类机器人在复杂的使用条件下,各种参数对步态规划及其稳定性的影响分析研究具有重要意义。本文首先根据与步态规划密切相关的机械结构特点、自由度以及关节配置等建立了步行椅机器人的简化模型以及步态规划的算法,然后基于ZMP理论和稳定裕度的概念,确立了主要步行参数与稳定性之间的关系,提出了动态步行的稳定性判据,分析了步态规划中步行参数对于稳定性的影响,并给出了在不考虑参数间耦合影响的前提下步态规划中参数选择的合理范围。     

两足机器人步行运动参数对单足支撑期ZMP点影响的研究

在两足步行机器人的研究中,一般将零力矩点(ZMP点)的位置与支撑范围的关系作为判别其步行稳定性的依据.提出一种通用的方法,来分析两足机器人的步行运动参数对ZMP点位置的影响,并通过对机器人单足支撑期运动的计算机仿真,试图得到步行运动参数的变化对稳定性影响的规律,以期对机器人动态步行的稳定性设计提供实用的参考.     

基于Pro/E和ADAMS的双足步行机器人造型及仿真研究

对步行机器人的双足进行了三维造型及运动仿真研究。首先利用通用软件Pro/E对人形机器人支撑受力部位腿部进行了三维造型的设计与装配,并在相应软件中检测了装配的正确性及精确度。然后根据ZMP稳定判据分析得出机器人步行的稳定性条件,最后将腿部模型其导入ADAMS中并对其进行了步行运动仿真。研究结果表明,所设计的步行机器人双足关节转角插值正确合理、无干涉,能够较好满足双足机器人的步行需要,论文成果具备一定参考价值和积极意义。     

基于Pro／E和ADAMS的双足步行机器人三维造型及仿真

随着科技的发展,机器人技术及仿真技术飞速发展。双足步行机器人相对于四足和多足机器人,其运动的稳定性和可靠性更难保证。现利用如今使用广泛、通用性强的Pro／E软件对人形机器人运动过程中最主要的支撑受力部位——腿部,进行三维的造型设计与装配,阐述其造型步骤及注意事项,并在零力矩判据下得出转动关节的转角值。为了更方便的研究机器人的稳定步行过程中各关节转角的插值,将腿部模型简化后倒入ADAMS中进行步行仿真实验,经观测其步行过程的平稳度,验证了关节转角插值的正确合理性。     

双足机器人稳定性生理论研究

针对双足机器人稳定性理论研究.详细介绍了ZMP的测量与计算方法,ZMP稳定性判据的概念以及适用条件,通过分析表明,ZMP稳定性判据可以应用于足球机器人、舞蹈机器人等复杂运动中,为ZMP稳定性判据在实际研究中的应用提供了理论依据.     

双足机器人运动学分析与仿真

完成双足步行机器人腿部尺寸的设计,并进行运动学分析.通过运动模型分析机器人腿部完成部分腰部转动功能的情况,运用MATLAB完成运动学计算并生成数据.运用Pro/E完成机器人腿部模型的建立,并完成仿真.研究结果为后续研究双足机器人动力学问题和机器人控制打下必要的基础.     

Biped walking robot based on a 2-UPU+2-UU parallel mechanism

Existing biped robots mainly fall into two categories： robots with left and right feet and robots with upper and lower feet. The load carrying capability of a biped robot is quite limited since the two feet of a walking robot supports the robot alternatively during walking. To improve the load carrying capability, a novel biped walking robot is proposed based on a 2-UPU＋2-UU parallel mechanism. The biped walking robot is composed of two identical platforms（feet） and four limbs, including two UPU（universal-prismatic-universal serial chain） limbs and two UU limbs. To enhance its terrain adaptability like articulated vehicles, the two feet of the biped walking robot are designed as two vehicles in detail. The conditions that the geometric parameters of the feet must satisfy are discussed. The degrees-of-freedom of the mechanism is analyzed by using screw theory. Gait analysis, kinematic analysis and stability analysis of the mechanism are carried out to verify the structural design parameters. The simulation results validate the feasibility of walking on rugged terrain. Experiments with a physical prototype show that the novel biped walking robot can walk stably on smooth terrain. Due to its unique feet design and high stiffness, the biped walking robot may adapt to rugged terrain and is suitable for load-carrying.     

Kinematics and dynamics analysis of a quadruped walking robot with parallel leg mechanism

It is desired to require a walking robot for the elderly and the disabled to have large capacity,high stiffness,stability,etc.However,the existing walking robots cannot achieve these requirements because of the weight-payload ratio and simple function.Therefore,Improvement of enhancing capacity and functions of the walking robot is an important research issue.According to walking requirements and combining modularization and reconfigurable ideas,a quadruped/biped reconfigurable walking robot with parallel leg mechanism is proposed.The proposed robot can be used for both a biped and a quadruped walking robot.The kinematics and performance analysis of a 3-UPU parallel mechanism which is the basic leg mechanism of a quadruped walking robot are conducted and the structural parameters are optimized.The results show that performance of the walking robot is optimal when the circumradius R,r of the upper and lower platform of leg mechanism are 161.7 mm,57.7 mm,respectively.Based on the optimal results,the kinematics and dynamics of the quadruped walking robot in the static walking mode are derived with the application of parallel mechanism and influence coefficient theory,and the optimal coordination distribution of the dynamic load for the quadruped walking robot with over-determinate inputs is analyzed,which solves dynamic load coupling caused by the branches’ constraint of the robot in the walk process.Besides laying a theoretical foundation for development of the prototype,the kinematics and dynamics studies on the quadruped walking robot also boost the theoretical research of the quadruped walking and the practical applications of parallel mechanism.     

Optimal trajectory generation for biped robots walking up-and-down stairs

This paper proposes an optimal trajectory generation method for biped robots for walking up-and-down stairs using a Real-Coded Genetic Algorithm (RCGA). The RCGA is most effective in minimizing the total consumption energy of a multi-dof biped robot. Each joint angle trajectory is defined as a 4-th order polynomial of which the coefficients are chromosomes or design variables to approximate the walking gait. Constraints are divided into equalities and inequalities. First, equality constraints consist of initial conditions and repeatability conditions with respect to each joint angle and angular velocity at the start and end of a stride period. Next, inequality constraints include collision prevention conditions of a swing leg, singular prevention conditions, and stability conditions. The effectiveness of the proposed optimal trajectory is shown in computer simulations with a 6-dof biped robot model that consists of seven links in the sagittal plane. The optimal trajectory is more efficient than that generated by the Modified Gravity-Compensated Inverted Pendulum Mode (MGCIPM). And various trajectories generated by the proposed GA method are analyzed from the viewpoint of the consumption energy: walking on even ground, ascending stairs, and descending stairs.     

两足步行机器人并联腿机构的步态规划及仿真

应用虚拟样机技术,建立了两足步行机器人并联腿机构的仿真模型,并在仿真环境下对步行机器人的行走姿态进行了规划和仿真试验,为确定步行机器人腿机构的结构参数和参数优化提供了实验平台,为研究和开发新型两足步行机器人及其控制奠定了理论基础。     

教学型双足步行机器人直线行走步态稳定规划方法

通过对双足机器人行走步态的研究,利用多项式插值法对双足机器人直线行走步态进行规划,分析了踝关节轨迹和髋关节轨迹,通过调节单腿支撑期和双腿支撑期的比例系数来调整机器人的行走步态,使其实现稳定步行。再通过ADAMS建立虚拟样机仿真实验,验证了这种步态规划方法的正确性与可行性。     

Energetic walking gaits studied by a simple actuated inverted pendulum model

The mechanical structure and the joint torques configuration are the important parts in the biped robot design. Meanwhile, different walking speed and step length should be chosen to achieve efficient gait according to different need of walking environment. Therefore, this paper investigates the energetic walking gaits using a simple actuated inverted pendulum model. Joint torques and push-off impulse are both added in the model. The walking gaits with different joint torques configuration and with different combination of walking speeds and step lengths are analyzed. The results show that hip velocity direction is changed by the push-off impulse just before the heelstrike, which reduces the energy consumption of each step. The walking gait with minimal energy consumption is the walking pattern only with push-off, the energy cost of which is 1/4 of the walking pattern only with joint torque during the swing phase. The cost of transport (COT) and the push-off impulse of the walking gait is increasing with the increase of walking speed and step length. Using same value of push-off impulse, the walking with long step length and slow speed is more efficient. The paper can provide suggestions for designing advanced legged robot systems with high energy efficiency and various gaits. For example, the consideration of push-off mechanism can be used in the biped robots design.