Kinematic mechanism and path planning of the Essboard

In this paper, we study the kinematic mechanism and path planning for a two-caster nonholonomic vehicle (the Essboard) which is a recent variant of skateboard. Different from the most studied Snakeboard, the Essboard consists of a torsion bar and two platforms, each of which contains a pedal and a caster. We first investigate the relationship between the tilt angles of the pedals and the wheel directions of the casters. This relationship reveals how to control the wheel directions by adjusting the tilt angles. Next, the rotational radius of the Essboard is derived for a given pair of tilt angles of both pedals. The rotational radius of the Essboard is much different than that of the Snakeboard. Then we develop a path-planning algorithm for the Essboard to move from a start position to the goal, using a series of consecutively connected arcs, which are tangent to each other at the connected points. It is shown from a kinematic point of view that the path planning of the Essboard can be solved by a series of pairs of pedals’ tilt angles. Three experiments are conducted to confirm the correctness of the main results. The results in this paper are a foundation for further study of the Essboard.     

Variable-model SMA-driven spherical robot

In this paper, we introduce a bionic spherical robot. This research has been inspired by the muscular organs and modularity of organisms such as starfish and octopuses. The robot that we fabricated uses five soft feet to crawl like a starfish, and the robotic feet are driven by the shape memory alloy springs. The robotic spherical structure and the soft feet were fabricated by 3 D printing. The robotic feet were made of silicone gel; these feet could bend upward and downward to help the robot to crawl on the ground and roll down a slope. The shell separation module installed inside the robot could divide the robot into two identical modules, and this smart structure could enhance the robotic flexibility in a small space. We performed force analysis and robotic simulation, and the results verified the feasibility of the model. The robot can switch between rigidity and softness by using human control. Three types of gaits have been proposed for controlling robotic movement and improving robotic flexibility in movement; these include rolling, crawling, and avoiding obstacles. The results of this study indicate that the variable-model design of the robot is an effective way to enhance the flexibility of soft robots.     

A micro-adjusting attitude mechanism for autonomous drilling robot end-effector

Drilling end-effector is a key unit in autonomous drilling robot. The perpendicularity of the hole has an important influence on the quality of airplane assembly. Aiming at the robot drilling perpendicularity, a micro-adjusting attitude mechanism and a surface normal measurement algorithm are proposed in this paper. In the mechanism, two rounded eccentric discs are used and the small one is embedded in the big one, which makes the drill＇s point static when adjusting the drill＇s attitude. Thus, removal of drill＇s point position after adjusting the drill attitude can be avoided. Before the micro-adjusting progress, four non-coplanar points in space are used to determine a unique sphere. The normal at the drilling point is measured by four laser ranging sensors. The adjusting angles at which the motors should be rotated to adjust attitude can be calculated by using the deviation between the normal and the drill axis. Finally, the motors will drive the two eccentric discs to achieve micro-adjusting progress. Experiments on drilling robot system and the results demonstrate that the adjusting mechanism and the algorithm for surface normal measurement are effective with high accuracy and efficiency.     

Wing load investigation of the plunge-diving locomotion of a gannet Morus inspired submersible aircraft

In this paper,we studied the wing root pivot joint’s radial load of a submersible airplane which imitates the locomotion of gannet’s Morus plunge-diving,by implementing a test device name Mimic-Gannet.The housing of the device was designed by mimicking the morphology of a living gannet,and the folding wings were realized by the mechanism of variable swept back wing.Then,the radial loads of the wing root were obtained under the conditions of different dropping heights,different sweptback angles and different water-entry inclination angles(i.e.,the angle between the longitudinal body axis and the water surface),and the relationships between the peak radial load and the above three parameters were analyzed and discussed respectively.In the studied areas,the minimum peak radial load of the pivot joint is 50.93 N,while the maximum reaches up to1135.00 N.The largest peak load would be generated for the situation of vertical water entry and zero wing sweptback angle.And it is of great significance to choose the three parameters properly to reduce the pivot joint’s radial load,i.e.,larger wing sweptback angle,smaller dropping height and water-entry inclination angle.It is also concluded that the peak radial load on the wing root is closely linear with the water-entry dropping height and the wing sweptback angle with a significant correlation.Eventually,the relationship between the wing load and the dropping height,water-entry inclination angle or wing sweptback angle,could be used to calculate the wing load about plunge-diving of a submersible aircraft,and the conclusions reveal the wing load characteristic of the gannet’s plunge process for the biologists.     

服务机器人技术研究现状与发展趋势

服务机器人技术经过近30年的发展,在机械、信息、材料、控制、医学等多学科交叉方面取得了重要的成果,本文结合作者在机器人领域的相关工作,在分析国内外关于服务机器人发展研究现状的基础上,就服务机器人目前涉及的仿生材料与结构、自重构机器人、复杂环境下机器人动力学问题、智能认知与感知、网络化交互及微纳系统等关键技术的研究进展做简要的综述,并概要展望了其发展趋势.希望能够在把握国际服务机器人前沿技术发展动态的同时,为培育我国服务机器人产业提供相关理论、方法及技术.