基于ADAMS的双足机器人拟人行走动态仿真

在双足机器人HEUBR_1的设计中,下肢采用了一种新的串并混联的仿人结构,并在足部增加了足趾关节.为验证该仿人结构设计的合理性及拟人步态规划的可行性,在ADAMS虚拟环境中建立了双足机器人HEUSR_1的仿真模型.通过拟人步态规划生成了运动仿真数据,在ADAMS虚拟环境中实现了具有足趾运动的拟人稳定行走,经仿真分析,获得了双足机器人HEUBR_1拟人行走步态下的运动学和动力学特性,仿真结果表明:双足机器人HEUBR_1的串并混联的仿人结构设计能够满足行走要求,且拟人步态规划方法可行,有足趾运动的拟人行走具有运动平稳、能耗低、足底冲击力小的特点.稳定行走的仿真步态数据可为下一步双足机器人HEUBR_1样机行走实验提供参考数据.     

基于六维力/力矩传感器和关节力矩的仿人机器人步态补偿算法

为实现仿人机器人的稳定行走，提出一种根据其足底六维力/力矩传感器信息、针对关节力矩的步态补偿算法．利用直流伺服电机的过载能力，来改善仿人机器人关节在大负载扰动下的动态性能．行走实验证明了该算法在离线实施过程中的有效性．     

面向仿人机器人自然步态规划的人体步行实验分析

自然步态规划方法是实现仿人机器人步态柔顺和能量优化的可行方法,该方法要求对人体步行及其平衡策略进行定量研究．本文分析自然步态规划方法的原理,建立了一套快捷有效的人体步态测试系统,并通过实验建立了人体步行的参数化数据库．实验结果揭示了人体步行的参数化特征及其平衡策略,对于仿人机器人的自然步态规划及控制提供了理论指导．结论特别指出,仅仅通过规划的方式实现仿人机器人的自然步态是不完备的,自然步态的实现必须同仿生控制策略相结合．同时实验结论对于仿人机器人的本体优化设计也提供了参考．     

基于体感的仿人机器人步态学习与控制

针对现有理想化步态动力学模型规划方法复杂、人为指定参数过多、计算量大的问题,提出一种基于体感数据学习人体步态的仿人机器人步态生成方法。首先,用体感设备收集人体骨骼信息,基于最小二乘拟合方法建立人体关节局部坐标系;其次,搭建人体与机器人映射的运动学模型,根据两者间主要关节映射关系,生成机器人关节转角轨迹,实现机器人对人类行走姿态的学习;然后,基于零力矩点(ZMP)稳定性原则,对机器人脚踝关节转角采用梯度下降算法进行优化控制;最后,在步态稳定性分析上,提出使用安全系数来评价机器人行走稳定程度的方法。实验结果表明,步行过程中安全系数保持在0~0.85,期望为0.4825,ZMP接近于稳定区域中心,机器人实现了仿人姿态的稳定行走,证明了该方法的有效性。     

基于ADAMS的双足机器人建模与仿真

为了提高双足机器人的设计效率,可以通过虚拟样机技术对其进行设计与仿真。针对机器人设计双足行走步态,首先以实际的物理样机为原型,建立双足机器人的七连杆模型,并用解析法求得机器人的逆运动学模型;然后在ADAMS软件中建立参数化的虚拟样机模型,在Matlab软件中规划双足机器人在平地上的完整行走步态;最后将规划的步态导入ADAMS中,在虚拟样机上实现了双足机器人的行走仿真。仿真结果与规划的行走步态基本一致,验证了虚拟样机的有效性,从而为双足机器人的设计与步态规划提供了一种新的方法和可靠依据。     

基于ODE 引擎的开放式仿人机器人仿真

为了获得灵活、开放、简洁的仿真功能,提出了一种基于ODE（open dynamics engine）的仿人机器人 仿真平台集成方案．将基于ODE 的仿人机器人仿真系统开发过程定义为两类运算：变换叠加和关节叠加,并设计 了这两类叠加的ODE 算法．将仿人机器人结构描述为一个设计者和计算机都可以理解的结构表,将该结构表翻译 为ODE 基本元素实现仿真．设计并实现了一个基于所提出方案的仿人机器人仿真平台,根据基于倒立摆的步态规 划思想,设计并在仿真平台上实现了双足步行的仿真实验．实验证明了文中方法的有效性．     

小型双足步行机器人的步态规划

为了解决双足步行机器人的步态控制,实现机器人稳定步行.为加强机器人的行走稳定性和优化步态过程,通过构造机器人行走过程中应满足的约束条件,规划机器人行走时的基本姿态及重心轨迹.根据规划的行走姿态及轨迹建立运动学方程,求解方程得到机器人各关节的运动轨迹.通过Matlab软件进行对运动轨迹模型的仿真,仿真得到的结果与设想的结果一致,证明步行得到平滑的关节轨迹是平稳的,并验证了方法的可行性.     

基于ZMP的拟人机器人步态规划

拟人机器人具有广阔的应用前景,研制工作得到了各国的重视,近年来已取得巨大的 进展,但仍存在大量的理论和技术问题有待深入研究,基于零力矩点（ZMP）的轨迹规划是 需解决的关键技术之一．本文比较分析了一般的双足步行机与拟人机器人的步态规划特点和 基于双足步行的两步规划方法,提出了一种适用于拟人机器人步态规划的新方法——逆两步 规划法,仿真研究表明采用这种方法规划ZMP轨迹是可行的．     

平面双足机器人虚拟斜坡行走步态生成算法研究

在平面双足机器人上应用虚拟斜坡行走方法设计了具有4个参数的步态生成算法．根据虚拟斜坡行走成立的基本条件研究了步态参数之间的关系,最终将独立参数减少到3个．步态参数具有明确的物理意义,可以实时地、便捷地调节行走速度．在平面机器人Stepper上采用所提出的步态生成算法,实现了1.243.88腿长秒的连续速度切换．     

基于深度Q网络的仿人机器人步态优化

为实现仿人机器人快速稳定的行走，在满足有效参数组合的条件下，提出一种基于深度强化学习的步行参数训练算法以优化机器人步态。首先，从环境中捕获机器人步态模型参数作为DQN的输入；然后，用DQN来拟合机器人行走产生的状态-动作值函数；最后，通过动作选择策略选择当前机器人执行的步态动作，同时产生奖励函数达到更新DQN的目的。选择NAO仿真机器人为实验对象，在RoboCup3D仿真平台上进行实验，结果证明在此算法下，NAO仿人机器人可以获得稳定的双足步行。     

Development of a leg part of a humanoid robot-design of a biped walking robot having antagonistic driven joints using a nonlinear spring mechanism

The authors are engaged in studies of biped walking robots from the following two viewpoints. One is a viewpoint as a human science. The other is a viewpoint towards the development of humanoid robots. In the current research concerning a biped walking robot, there is no developed example of a life-size biped walking robot with antagonistically driven joints by which the human musculo-skeletal system is imitated in the lower limbs. Humans are considered to exhibit walking behavior which is both efficient and capable of flexibly coping with contact with the outside environment. However, developed biped walking robots cannot realize human walking. The human joint is driven by two or more antagonistic muscle groups. Humans can vary the joint stiffness, using nonlinear spring characteristics possessed by the muscles themselves. The function is an indispensable function for a humanoid. Therefore, the authors designed and built an anthropomorphic biped walking robot having antagonistic driven joints. In this paper, the authors introduce the design method of the robot. The authors performed walking experiments with the robot. As a result, a quasi-dynamic biped walking using antagonist driven joint was realized. The walking speed was 7.68 s per step with a 0.1 m step length.     

仿人机器人两步步态规划算法研究

为了进一步提高仿人机器人步行时的稳定性,通过对人类步行的研究,并从两足步行机的两步步态规划方法中得到启发,对仿人机器人步行也进行类似的两步规划,但由于结构上的不同,仿人机器人中采用加入上肢运动补偿的方式实现平衡.规划仿人机器人的运动姿态,然后根据零力矩点必须落在稳定区域的原则,对仿人机器人的上肢运动轨迹进行求解,通过这种加入上肢补偿的两步规划来实现仿人机器人的稳定步行.从实验结果可以看出,采用这种两足步态规划方法,在仿人机器人两足步行时,可以使机器人上肢与下肢协调运动,从而提高了步行的稳定性.     

Quasi optimal sagittal gait of a biped robot with a new structure of knee joint

The design of humanoid robots has been a tricky challenge for several years. Due to the kinematic complexity of human joints, their movements are notoriously difficult to be reproduced by a mechanism. The human knees allow movements including rolling and sliding, and therefore the design of new bio-inspired knees is of utmost importance for the reproduction of anthropomorphic walking in the sagittal plane. In this article, the kinematic characteristics of knees were analyzed and a mechanical solution for reproducing them is proposed. The geometrical, kinematic and dynamic models are built together with an impact model for a biped robot with the new knee kinematic. The walking gait is studied as a problem of parametric optimization under constraints. The trajectories of walking are approximated by mathematical functions for a gait composed of single support phases with impacts. Energy criteria allow comparing the robot provided with the new rolling knee mechanism and a robot equipped with revolute knee joints. The results of the optimizations show that the rolling knee brings a decrease of the sthenic criterion. The comparisons of torques are also observed to show the difference of energy distribution between the actuators. For the same actuator selection, these results prove that the robot with rolling knees can walk longer than the robot with revolute joint knees.     

基于运动相似性的仿人机器人双足步行研究

提出了一种基于人体步行运动相似性的仿人机器人双足步行动作设计方法．改进了人体步行轨迹的参 数获取与相似性匹配系统,扩展了相似性函数的适用范围．根据仿人机器人的机械连杆特点定义了步行运动周期中 的关键姿势与子相变换,建立了运动学约束方程,并对行走中出现的动态稳定性问题进行了约束．仿真和实体机器 人实验验证了该方法的有效性．     

Walking Control Algorithm of Biped Humanoid Robot on Uneven and Inclined Floor

This paper describes walking control algorithm for the stable walking of a biped humanoid robot on an uneven and inclined floor. Many walking control techniques have been developed based on the assumption that the walking surface is perfectly flat with no inclination. Accordingly, most biped humanoid robots have performed dynamic walking on well designed flat floors. In reality, however, a typical room floor that appears to be flat has local and global inclinations of about 2°. It is important to note that even slight unevenness of a floor can cause serious instability in biped walking robots. In this paper, the authors propose an online control algorithm that considers local and global inclinations of the floor by which a biped humanoid robot can adapt to the floor conditions. For walking motions, a suitable walking pattern was designed first. Online controllers were then developed and activated in suitable periods during a walking cycle. The walking control algorithm was successfully tested and proved through walking experiments on an uneven and inclined floor using KHR-2 (KAIST Humanoid robot-2), a test robot platform of our biped humanoid robot, HUBO.     

仿人机器人上楼梯行走稳定性研究

针对仿人机器人上楼梯行走稳定性问题,进行了步态规划、稳定区域和稳定裕量的计算、控制策略等关键技术的研究。通过仿真,得到稳定行走姿态变化情况及各关节参数,为研究实时控制提供了依据。     

基于六维力／力矩传感器的拟人机器人实际ZMP检测

ZMP（Zero Moment Point)作为双足双行机器人动态稳定行走的判据,已应用于世界上银多著名的步行机器人系统。目前国外步行机器人大多采用力／力矩传感器进行ZMP的实际检测计算,但采用六维力／力矩传感器的却不多,而且其安装位置也各不同,国内机器人还都还都处于离线步态规划阶段,只进行理论了ZMP的计算,并没有进行实时检测。本文根据清华大学985重点项目“拟人机器人技术及其系统研究”的研究要求,确定基于六维力／力矩传感系统的实际ZMP检测方案,确这了传感器安装的最佳位置,推导了单脚支撑期,双脚支撑期的实际ZMP计算公式提出了基于ZMP理论的姿态调整方法,以期在实际应用中进行在线步态规划。     

Analyses of biped walking posture by dynamical-evaluating index

In this paper, biped walking posture and design are evaluated through dynamic reconfiguration manipulability shape index (DRMSI). DRMSI is the concept derived from dynamic manipulability and reconfiguration manipulability with remaining redundancy. DRMSI represents the ability of dynamical system of manipulators possessing shape changing acceleration in task space by normalized torque inputs, while the hand motion is assigned as the primary task. Besides, we use visual lifting approach to stabilize the walking and stop falling down. In this research, the primary task is to make the position of the head direct to the desired one as much as possible. And realizing the biped walking is the second task. This research indicates that proposed dynamical-evaluating index is effective in evaluating the biped walking motion and biped humanoid robot has the adjustable configuration to walk with higher flexibility. Flexibility represents the dynamical shape changeability of humanoid robot based on redundancy of the humanoid robot with the premise of the primary task given to keeping the head position high.     

A Biologically Inspired Biped Locomotion Strategy for Humanoid Robots: Modulation of Sinusoidal Patterns by a Coupled Oscillator Model

Biological systems seem to have a simpler but more robust locomotion strategy than that of the existing biped walking controllers for humanoid robots. We show that a humanoid robot can step and walk using simple sinusoidal desired joint trajectories with their phase adjusted by a coupled oscillator model. We use the center-of-pressure location and velocity to detect the phase of the lateral robot dynamics. This phase information is used to modulate the desired joint trajectories. We do not explicitly use dynamical parameters of the humanoid robot. We hypothesize that a similar mechanism may exist in biological systems. We applied the proposed biologically inspired control strategy to our newly developed human-sized humanoid robot computational brain (CB) and a small size humanoid robot, enabling them to generate successful stepping and walking patterns.     

Position-based impedance control of a biped humanoid robot

This paper describes position-based impedance control for biped humanoid robot locomotion. The impedance parameters of the biped leg are adjusted in real-time according to the gait phase. In order to reduce the impact/contact forces generated between the contacting foot and the ground, the damping coefficient of the impedance of the landing foot is increased largely during the first half double support phase. In the last half double support phase, the walking pattern of the leg changed by the impedance control is returned to the desired walking pattern by using a polynomial. Also, the large stiffness of the landing leg is given to increase the momentum reduced by the viscosity of the landing leg in the first half single support phase. For the stability of the biped humanoid robot, a balance control that compensates for moments generated by the biped locomotion is employed during a whole walking cycle. For the confirmation of the impedance and balance control, we have developed a life-sized humanoid robot, WABIAN-RIII, which has 43 mechanical d.o.f. Through dynamic walking experiments, the validity of the proposed controls is verified.