可侧向摆动的欠驱动双足机器人

为解决机器人的侧向平衡问题,同时为使机器人的行走空间由二维扩展到三维,确立了可以侧向周期稳定偏转的有弹性脚的欠驱动步行机器人模型。根据混合动力系统的特点,建立了侧向摆动方程及脚碰撞地面的方程,并利用数值仿真得到了不同初始状态下的稳定极限环。根据运动状态分析,找到了弹性脚的欠驱动步行机器人所允许的侧向偏转范围。施加基于能量的控制可以消除摆动过程中出现的干扰,使欠驱动步行机器人回归到稳定状态,稳定的侧向摆动保证了欠驱动步行机器人的稳定行走。     

欠驱动两足步行机器人侧向稳定控制方法研究

以欠驱动两足步行机器人为对象研究其侧向运动稳定控制问题。首先分析引起机器人侧向运动不稳定的原因,然后提出步宽控制和侧向力矩补偿两种控制策略。步宽控制通过控制机器人侧向落脚位置,使其侧向运动周期与前向周期趋于一致实现侧向运动稳定。力矩补偿控制通过在踝关节引入侧向控制力矩,使侧向运动与前向运动协调一致实现侧向运动稳定。仿真实验表明,机器人实现了稳定的3D动态行走,达到了预期的控制效果。     

七连杆双足机器人建模和控制系统仿真

研究双足机器人稳定性控制问题,步行机器人作为一种载运工具适应地况能力强,结构复杂,运动控制难.实现类人型机器人动态行走,针对行走的稳定性,必须对机器人进行动力学建模、步态设计和稳定姿态控制算法设计.研究了一种七连杆双足机器人的动力学建模和控制系统仿真方法.建立两足步行机器人腿的可参数化仿真模型,对七平面双足机器人的运动情况和控制输入输出进行仿真,得出试验结果.并对影响步行机器人稳定性能的参数进行分析,为后面机器人样机的研制提供理论及数据依据.     

国内外两足步行机器人研究的历史、现状及发展趋势

本文共分6个部分,详细介绍了研究两足步行机器人的原因和目的,两足步行机器人的特点及其应用前景,国内外两足步行机器人研究的历史、现状及发展趋势.     

欠驱动双足机器人动态步态规划方法研究

以欠驱动双足机器人为对象研究其周期稳定的动态步态规划方法。首先建立欠驱动双足机器人的混杂动力学模型,然后采用时不变步态规划策略对机器人步态进行规划,并研究周期步态的收敛条件。步态参数直接决定周期步态的稳定性,采用遗传算法,以能耗最优为目标,以限制条件为约束对步态参数进行选择和优化。最后通过虚拟样机对机器人的行走过程进行动力学仿真。实验表明规划步态收敛于稳定的极限环,实现了高速动态步行,该规划方法是可行的。     

一种单动力三杆两足移动机构

提出一种新概念移动机构．其机器人特征为具有两个足,能够两足接地实现类似步行的步态．其机构学特性为：是一种开链串联三杆机构;由3个机件和2个转动副组成;具有2个自由度;仅用一个动力机进行驱动,是一种欠驱动机构．进行了步态分析,并通过计算机仿真进行了验证．进行了稳定性分析,并对该两足移动机构的概念进行了拓展．制作了两台样机,实现了期望的移动．     

本期摘要

舵机控制步行机器人系统设计 首先设计了两足步行机器人的本体结构,并选择舵机作为驱动源。然后．基于广义坐标对该机器人进行了运动学建模,该方法运算简便直观易懂。重点讨论了动态步行的算法设计,详细分析了基于零力矩点的仿人机器人动态步行运动规划方法。结合机器人的几何约束和运动约束．推导机器人参数化步态设计的推导公式,机器人步态的参数化设计大大方便了机器人的运动学和动力学分析。     

基于质心运动状态的双足机器人欠驱动步行稳定控制

针对双足机器人欠驱动步行稳定控制问题,提出一种基于机器人质心(Co M)运动状态的前馈控制策略.首先,根据步行速度与步行稳定性的关系,提出一种基于步行速度的欠驱动步行稳定性直观表述并给予数学定义:如果机器人步行速度能够始终收敛于一个已被证明可维持步行的速度,则机器人步行处于稳定状态;然后,基于该直观表述的数学定义和人类变速步行时的步态特征,提出一种基于质心运动状态的前馈控制策略,控制策略以机器人质心水平速度作为系统输出,通过控制质心在单个步行周期内的位移,实现对质心水平运动速度的控制,进而实现稳定步行;最后,在混凝土和木板地面上,成功实现了平均步行速度0.178 m/s、步幅为腿长0.31倍的欠驱动步行.试验结果表明:所提出的控制策略能够通过控制质心对理想速度的跟踪,实现欠驱动稳定步行.     

舵机控制步行机器人系统设计

首先设计了两足步行机器人的本体结构,并选择舵机作为驱动源。然后,基于广义坐标对该机器人进行了运动学建模,该方法运算简便、直观易懂。重点讨论了动态步行的算法设计,详细分析了基于零力矩点的仿人机器人动态步行运动规划方法。结合机器人的几何约束和运动约束,推导机器人参数化步态设计的推导公式,机器人步态的参数化设计大大方便了机器人的运动学和动力学分析。最后,介绍了运动规划的实验设计,并对关节调试作了总结和分析,指出了存在的问题和解决的办法。     

欠驱动步行机器人实时仿真系统设计

开发了异构多软件平台融合的机器人实时仿真系统。在欠驱动步行机器人动力学建模中引入虚拟样机技术,利用ADAMS软件生成动力学模型,利用MATLAB软件设计控制器,二者通过接口实现联合仿真;在开发人机界面及连接各个模块的接口中引入MATLAB和VC＋＋混合编程技术,完成对硬件的驱动控制及系统平台的操作。该仿真系统实现对欠驱动步行机器人进行理论步态仿真、控制方法的开发及实验研究,对实体机器人的控制调试、实时控制算法的设计。     

面向离散地形的欠驱动双足机器人平衡控制方法

欠驱动双足机器人在行走中为保持自身的平衡, 双脚需要不间断运动. 但在仅有特定立足点的离散地形上很难实现调整后的落脚点, 从而导致欠驱动双足机器人在复杂环境中的适应能力下降. 提出了基于虚拟约束(Virtual constraint, VC)的变步长调节与控制方法, 根据欠驱动双足机器人当前状态与参考落脚点设计了非时变尺度缩放因子, 能够实时重构适应当前环境的步态轨迹; 同时构建了全身动力学模型, 采用反馈线性化的模型预测控制 (Model predictive control, MPC) 滚动优化产生力矩控制量, 实现准确的轨迹跟踪控制. 最终进行了欠驱动双足机器人的随机离散地形稳定行走的仿真实验, 验证了所提方法的有效性与鲁棒性.     

Stability and control of dynamic walking for a five-link planar biped robot with feet

During dynamic walking of biped robots, the underactuated rotating degree of freedom (DOF) emerges between the support foot and the ground, which makes the biped model hybrid and dimension-variant.This paper addresses the asymptotic orbit stability for criterion for DVHS is also presented, and the result is then used to study dynamic walking for a five-link planar biped robot with feet. Time-invariant gait planning and nonlinear control strategy for dynamic walking with flat feet is also introduced. Simulation results indicate that an asymptotically stable limit cycle of dynamic walking is achieved by the proposed method.     

Efficiency analysis of telescopic-legged bipedal robots

This paper investigates the stability of underactuated bipedal walking incorporating telescopic-leg actuation. In human walking, knee joints of swing and support legs are bent and stretched. The telescopic legs mimic the motion of the center of mass of human legs via their telescopic motion during the stance phase. First, underactuated telescopic-legged biped robot models are introduced. Second, an output-following control law is applied to the linearized equation of motion of the robot, and the controlled robot’s equation is then specified as a linear time-varying system. The error transition equation is developed to evaluate the stability during the stance phase. Numerical calculations are performed to show the influences of leg telescopic motion on the stability.     

Stability and control of dynamic walking for a five-link planar biped robot with feet

During dynamic walking of biped robots, the underactuated rotating degree of freedom （DOF） emerges between the support foot and the ground, which makes the biped model hybrid and dimension-variant. This paper addresses the asymptotic orbit stability for dimension-variant hybrid systems （DVHS）. Based on the generalized Poincare map, the stability criterion for DVHS is also presented, and the result is then used to study dynamic walking for a five-link planar biped robot with feet. Time-invariant gait planning and nonlinear control strategy for dynamic walking with fiat feet is also introduced. Simulation results indicate that an asymptotically stable limit cycle of dynamic walking is achieved by the proposed method.     

Asymptotically stable walking for biped robots: analysis viasystems with impulse effects

Biped robots form a subclass of legged or walking robots. The study of mechanical legged motion has been motivated by its potential use as a means of locomotion in rough terrain, as well as its potential benefits to prothesis development and testing. The paper concentrates on issues related to the automatic control of biped robots. More precisely, its primary goal is to contribute a means to prove asymptotically-stable walking in planar, underactuated biped robot models. Since normal walking can be viewed as a periodic solution of the robot model, the method of Poincare sections is the natural means to study asymptotic stability of a walking cycle. However, due to the complexity of the associated dynamic models, this approach has had limited success. The principal contribution of the present work is to show that the control strategy can be designed in a way that greatly simplifies the application of the method of Poincare to a class of biped models, and, in fact, to reduce the stability assessment problem to the calculation of a continuous map from a subinterval of R to itself. The mapping in question is directly computable from a simulation model. The stability analysis is based on a careful formulation of the robot model as a system with impulse effects and the extension of the method of Poincare sections to this class of models     

Adaptive walking pattern generation and balance control of the passenger-carrying biped robot,HUBO FX-1, for variable passenger weights

A passenger-carrying biped robot is a practical robot capable of carrying a passenger for both entertainment purposes and disabled transport by means of biped walking. In the walking controls of the biped walking robot, changes in the payload are not generally considered. However, in the case of a passenger-carrying biped robot, the range of possible payloads for passenger weight is relatively wide, from zero to approximately one hundred kgf. In the authors’ previous research pertaining to passenger-carrying biped robots, the robot was modeled using a specific passenger weight; hence, the control parameters were tuned for it and kept to be constant. However, the previous method’s weakness was a decrease in the walking performance and walking stability of the robot when the passenger’s weight was much heavier or lighter than the predefined passenger weight. Therefore, in this paper, the walking pattern generation and balance control methods are developed to adaptively cope with variable passenger weights. These methods are then experimentally verified to ensure that the walking performance could be preserved uniformly for a variation of passenger weights.     

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.     

动态双足机器人的控制与优化研究进展

对动态双足机器人的可控周期步态的稳定性、鲁棒性和优化控制策略的国内外研究现状与发展趋势进行了探讨.首先,介绍动态双足机器人的动力学数学模型,进一步,提出动态双足机器人运动步态和控制系统原理;其次,讨论动态双足机器人可控周期步态稳定性现有的研究方法,分析这些方法中存在的缺点与不足;再次,研究动态双足机器人的可控周期步态优化控制策略,阐明各种策略的优缺点;最后,给出动态双足机器人研究领域的难点问题和未来工作,展望动态双足机器人可控周期步态与鲁棒稳定性及其应用的研究思路.