不平整地面仿人机器人行走控制策略

针对仿人机器人行走于不平整地面会失稳倾倒的现象,提出基于Kane碰撞原理的在线调节控制算法。该调节算法可以实现快速的动力学解算,估算出仿人机器人遇到障碍时地面对腿部的冲击力大小,据此调节仿人机器人的腿部及躯干姿态参数,使机器人成功稳定行走过凸起或凹陷障碍。采用Matlab的Simulink工具,仿真验证了5杆仿人机器人模型基于Kane在线调节控制算法平稳行走过障碍的过程。     

基于神经网络的仿人跑步机器人步态规划

为了快速生成仿人机器人跑步运动轨迹,研究了一种用于仿人机器人跑步步态生成的步态规划器。采用三维弹簧倒立摆模型描述跑步过程中仿人机器人质心运动规律,奔跑时机器人质心轨迹及落脚点位置可以由四个步态参数来确定,从而将步态规划问题转化成步态参数优化问题,求解了500余种不同运动状态下的步态参数。建立了基于三层BP神经网络的步态规划器,将优化结果作为训练样本训练神经网络。用上述规划器实现了仿人机器人跑步步态规划并对规划结果进行了仿真验证。研究结果表明,基于BP神经网络的步态规划器可以实现步态参数的快速计算,生成的跑步步态逼真;提出的跑步运动步态规划方法可行,为仿人机器人实时轨迹生成提供了一种解决方法。     

Gait design for an ice skating humanoid robot

Basic walking gaits are a common building block for many activities in humanoid robotics, such as robotic soccer. The nature of the walking surface itself also has a strong affect on an appropriate gait. Much work is currently underway in improving humanoid walking gaits by dealing with sloping, debris-filled, or otherwise unstable surfaces. Travel on slippery surfaces such as ice, for example, greatly increases the potential speed of a human, but reduces stability. Humans can compensate for this lack of stability through the adaptation of footwear such as skates, and the development of gaits that allow fast but controlled travel on such footwear.This paper describes the development of a gait to allow a small humanoid robot to propel itself on ice skates across a smooth surface, and includes work with both ice skates and inline skates. The new gait described in this paper relies entirely on motion in the frontal plane to propel the robot, and allows the robot to traverse indoor and outdoor ice surfaces more stably than a classic inverted pendulum-based walking gait when using the same skates. This work is demonstrated using Jennifer, a modified Robotis DARwIn-OP humanoid robot with 20 degrees of freedom.     

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.     

Direct comparison of psychological evaluation between virtual and real humanoids: Personal space and subjective impressions

The aim of this study was to compare psychological evaluations of a robot constructed using a virtual reality (VR) system (VR robot) with a real robot. The same design was used for both the VR and real robot in order to make a direct comparison. For the psychological evaluation, we measured behavioral reactions (the amount of personal space the participants desired between themselves and the robot) and subjective impressions (from a psychological scale). The psychological scale included six dimensions that are typically used to evaluate a humanoid: utility, clumsiness of motion, possibility of communication, controllability, vulnerability, and objective hardness. Sixty-one participants observed both the VR and real robots walking toward them and reported their level of desired personal space. Next, the participants evaluated their psychological impressions of the robots. The results indicated no significant difference in the level of desired personal space between the situations with the real and VR robots. However, regarding the psychological dimensions, participants reported higher scores for utility and the possibility of communication, and lower scores for controllability for the real robot as compared with the VR robot. The usability of a VR robot is discussed.     

基于干扰观测器的机器人关节控制

提出了基于干扰观测器的仿人机器人关节控制方法。在建立仿人机器人单关节物理模型的基础上,设计了相应的干扰观测器和控制器,解决了关节控制中时变非线性的重力力矩对控制性能的影响。与PID控制器进行性能比较,并探讨了关节模型摄动对干扰观测器的影响,仿真结果表明该方法在仿人机器人关节控制中的可行性和有效性。     

参数化优化的仿人机器人相似性前向倒地研究

提出了一种基于运动相似性的仿人机器人前向倒地动作设计方法.首先,分析了运动相似性并提出了关键姿势同步转换方法; 其次,为机器人前向倒地运动四级倒立摆建立了相似性变换条件下的动力学约束方程与关联的物理条件约束; 再次,引入参数化优化控制与强化技术,对机器人的触地过程进行了参数化优化.实验结果表明了该方法的有效性.     

Optimization of throwing motion planning for whole-body humanoid mechanism: Sidearm and maximum distance

Throwing is a rapid coordinated movement with high configuration and actuation redundancies. Based on a previous work, this paper advances a numerical framework that optimizes the throwing motions and generates the associated dynamic features for a whole-body humanoid mechanism. To generate physically feasible throwing motions in a fully predictive manner, rigorous dynamic models, such as actuation, biped balance based on Zero-Moment Point (ZMP), and ground reaction loads, are associated with the constraints. The algorithm outputs include the motion, required actuator torques, release parameters, and object projectile. Realistic human-like motions of sidearm and maximum distance throwing are generated as optimized solutions, which demonstrate valid kinematic and dynamic cause-effect relations. The sidearm throw shows better optimality than the overarm throw in terms of actuator torques under the proposed mechanical model; it is characterized by the unique hand trajectory and effective utilization of torso axial rotation. The maximum distance throw is associated with active movement of the arm and torso with larger ranges of motion; it is the release height and speed that increase accordingly.