一种双足机器人的滚动膝盖关节的设计

在双足机器人的研究中,一个关键点就在于如何能够得到和人类相似甚至更优的关节传动效率。滚动膝关节思想的提出就是通过减小关节内部的摩擦从而降低能量损耗这一途径来实现关节传动效率的提高。基于此提出了一种基于滚珠丝杠传动的滚动膝关节设计方案,同时从运动学以及动力学角度进行了分析,确定了运动参数。此后应用CATIA软件实现该结构的三维建模,并进行运动学仿真。     

Learning gait of quadruped robot without prior knowledge of the environment

Walking is the basic skill of a legged robot, and one of the promising ways to improve the walking performance and its adaptation to environment changes is to let the robot learn its walking by itself. Currently, most of the walking learning methods are based on robot vision system or some external sensing equipment to estimate the walking performance of certain walking parameters, and therefore are usually only applicable under laboratory condition, where environment can be pre-defined. Inspired by the rhythmic swing movement during walking of legged animals and the behavior of their adjusting their walking gait on different walking surfaces, a concept of walking rhythmic pattern(WRP) is proposed to evaluate the walking specialty of legged robot, which is just based on the walking dynamics of the robot. Based on the onboard acceleration sensor data, a method to calculate WRP using power spectrum in frequency domain and diverse smooth filters is also presented. Since the evaluation of WRP is only based on the walking dynamics data of the robot’s body, the proposed method doesn’t require prior knowledge of environment and thus can be applied in unknown environment. A gait learning approach of legged robots based on WRP and evolution algorithm(EA) is introduced. By using the proposed approach, a quadruped robot can learn its locomotion by its onboard sensing in an unknown environment, where the robot has no prior knowledge about this place. The experimental result proves proportional relationship exits between WRP match score and walking performance of legged robot, which can be used to evaluate the walking performance in walking optimization under unknown environment.     

带目标识别系统的双足机器人研究

针对带有目标识别系统的双足机器人的开发,采用S3C2400A微处理器作为控制器,基于嵌入式linux系统,完成了机器人目标识别模块和双足行走模块;在目标识别程序开发中,采用了梯度Hough变换,使得对目标识别的效率大大提高;在双足行走程序的开发中,采用32路舵机控制器,实现了对单个舵机控制或多个舵机同时控制,达到了双足行走协调统一的要求;通过串口通信的方式,将目标识别与舵机控制相结合,使得机器人能根据目标的位置,判断行走方向,并最终到达目标处。在开发样机上进行的实验研究,取得了较好的效果,证明了系统方案的可行性。     

Planning and Control of COP-Switch-Based Planar Biped Walking

Efficient walking is one of the main goals of researches on biped robots. A feasible way is to translate the understanding from human walking into robot walking, for example, an artificial control approach on a human like walking structure. In this paper, a walking pattern based on Center of Pressure (COP) switched and modeled after human walking is introduced firstly.Then, a parameterization method for the proposed walking gait is presented. In view of the complication, a multi-space planning method which divides the whole planning task into three sub-spaces, including simplified model space, work space and joint space, is proposed. Furthermore, a finite-state-based control method is also developed to implement the proposed walking pattern. The state switches of this method are driven by sensor events. For convincing verification, a 2D simulation system with a 9-link planar biped robot is developed. The simulation results exhibit an efficient walking gait.     

Short communication: Lameness impairs feeding behavior of dairy cows

The automated, reliable, and early detection of lameness is an important aim for the future development of modern dairy operations. One promising indicator of lameness is a change in the feeding behavior of a cow. In this study, the associations between feeding behavior and lameness were evaluated. A herd of 50 cows was investigated during the winter season in a freestall barn. Feeding behavior, feed intake, milk yield, and body weight were monitored using electronic feeding troughs and an automated milking system. Gait scoring every second week was used as a measure of lameness. To analyze the effect of lameness on feeding behavior and milk yield, linear mixed models were used. Cows with more severe lameness spent less time feeding per day (104 ± 4, 101 ± 4, and 91 ± 4 min/d for lameness scores 2, 3, and 4, respectively). An interaction between parity and lameness score was detected, with severely lame primiparous cows spending the least time feeding. Severely lame cows fed faster; however, their body weights were lower than for less-lame cows. Increase in lactation stage was associated with longer daily feeding time, longer duration of feeding bouts, and lower feeding rate. Worsening of gait was associated with lower silage intake and less time spent feeding even before severe lameness was scored. The results indicate that lameness is associated with changes in feeding behavior and that such changes could be considered in the future development of remote monitoring systems. It should also be noted that impaired feeding behavior along with lameness can put the welfare of especially early lactating primiparous cows at risk.     

沉浸式虚拟现实环境下走动对场景识别的影响

采用沉浸式虚拟现实技术,在典型空间更新范式下研究：①运动对场景识别的影响;②沉浸式虚拟现实技术本身在场景识别研究中的效度。组间变量是测试视点情况（与学习视点相同和与学习视点不同）,组内变量是桌子状况（桌子静止和旋转）。因变量是正确判断物体位置改变的比率。结果发现：①视点依赖效应：在相同测试视点的识别成绩显著好于在不同测试视点条件下的识别成绩。②空间更新效应：无论不同测试视点还是在相同视点条件下,桌子静止时的识别成绩显著好于桌子转动条件下的识别成绩。③沉浸式虚拟现实环境下获得与真实环境结果一致的模式,说明沉浸式虚拟现实技术是场景识别研究中的一种十分有效的方法。     

一种医用肠道机器人的理论分析与试验研究

提出一种结构简单的医用肠道机器人的驱动机构。利用弹性流体动压润滑理论,详细分析计算了肠道机器人在不同弹性模量、不同半径和不同粘液粘度的肠道内的轴向运行速度和形成的粘液膜厚度。结果表明,此种肠道机器人能以较快速度在肠道内悬浮运行。上述分析结果已被肠道试验研究所证实。     

蛇形机器人行波运动的研究

对蛇形机器人的行波运动机理进行了研究,基于Serpenoid曲线建立了蛇形机器人行波运动的形状控制模型、运动学模型、机构动力学模型及环境动力学模型,给出了求解过程。仿真结果表明：在行波运动中,各关节输入力矩大小呈周期变化,且随其与蛇体重心距离的增加而减小。蛇体中心关节的最大输入力矩为蛇形机器人所需最大输入力矩。对称关节输入力矩幅值变化规律相同,但相差不同;运动初始弯角保持不变,关节输入力矩随着环境摩擦因数的增加而增加。环境摩擦因数保持不变,关节输入力矩随着初始弯角的增加而减小。     

Biomimetic Experimental Research on Hexapod Robot's Locomotion Planning

To provide hexapod robots with strategies of locomotion planning, observation experiments were operated on a kind of ant with the use of high speed digital photography and computer assistant analysis. Through digitalization of original analog video, locomotion characters of ants were obtained, the biomimetic foundation was laid for polynomial trajectory planning of multi-legged robots, which was deduced with mathematics method. In addition, five rules were concluded, which apply to hexapod robots marching locomotion planning. The first one is the fundamental strategy of multi-legged robots’ leg trajectory planning. The second one helps to enhance the static and dynamic stability of multi-legged robots. The third one can improve the validity and feasibility of legs’ falling points. The last two give criterions of multi-legged robots’ toe trajectory figures and practical recommendatory constraints. These five rules give a good method for marching locomotion planning of multi-legged robots, and can be expended to turning planning and any other special locomotion.