Koh Hosoda Pengarang

Design and control of a novel variable stiffness soft arm Lina Haoa, Chaoqun Xiang a,b, M. E. Giannaccinib,c, Hongtai Chenga, Ying Zhanga, S. Nefti-Mezianib, and Steven Davisb aSchool of Mechanical Engineering & Automation, Northeastern University, Shenyang, People’s Republic of China; bSoft Robotics Group, Bristol Robotics Laboratory, University of Bristol, Bristol, UK; cCentre for Autonomous Systems and Advanced Robotics, University of Salford, Salford, UK ABSTR AC T Soft robot arms possess such characteristics as light weight, simple structure and good adaptability to the environment, among others. On the other hand, robust control of soft robot arms presents many difficulties. Based on these reasons, this paper presents a novel design and modeling of a fuzzy active disturbance rejection control (FADRC) controller for a soft PAM arm. The soft arm comprises three contractile and one extensor PAMs, which can vary its stiffness independently of its position in space. Force analysis for the soft arm is conducted, and stiffness model of the arm is established based on the relational model of contractile and extensor PAM. The accuracy of stiffness model for the soft arm was verified through experiments. Associated to this, a controller based on the fuzzy adaptive theory and active disturbance rejection control (ADRC), FADRC, has been designed to control the arm. The fuzzy adaptive theory is used to adjust the parameters of the ADRC, the control algorithm has the ability to control stiffness and position of the soft arm. In this paper, FADRC was further verified through comparative experiments on the soft arm. This paper reinforces the hypothesis that FADRC control, as an algorithm, indeed possesses good robustness and adaptive abilities. KEY WORDS Soft robot; variable stiffness; PAM; stiffness modeling; FADRC A quantized approach for occupancy grids for autonomous vehicles: Q-Trees Onur Sencan and Hakan Temeltas Depar tment of Control and Automation Engineering, Facult y of Elec trical and Elec tronics Engineering, Istanbul Technical Universit y, Istanbul, Turkey ABSTR AC T Map Representation of the Real World is an essential step in robotics for using the mathematical methods in an abstract way. In addition to grid-based and topological studies on this area, this paper uses both approaches representing the environment with independent graph trees for all axes. We are proposing a methodology that allows us to substitute point clouds on grids in an efficient way and can be easily adapted to multi-system approaches even in real time with low-level computational systems. KEY WORDS Space par titioning; grid mapping; graph trees; enviro nment modeling; occupanc y grids Dragging motion of a two-link mobile manipulator with large pull force through singular configuration: theoretical analysis and experimental verification Takateru Urakuboa, Eri Kitagawab, Xianglong Wanc and Tomoaki Mashimod aDepartment of Information Science, Kobe University, Kobe, Japan; bDepartment of Systems Science, Kobe University, Kobe, Japan; cDepartment of Mechanical Systems Engineering, Nagoya University, Nagoya, Japan; dElectronics-Inspired Interdisciplinary Research Institute, Toyohashi University of Technology, Toyohashi, Japan ABSTR AC T This paper reveals the advantageous feature of singular configuration for a two-link mobile manipulator by theoretical analysis, numerical simulations and experiments. When a mobile manipulator drags a heavy object on a flat floor, a large pull force is required to overcome the friction force between the object and the floor. In the motion obtained by numerical optimization, unlike humans, a two-link mobile manipulator pulls the object with a large force by passing through singular configuration. We analyze theoretically the force applied to the object by the manipulator under several assumptions, and show that a large pull force can be generated near singular configuration from the energy stored in the manipulator. The feasibility of the motion obtained by numerical optimization is also shown by experimental results. KEY WORDS Singularity; dynamics; kinematics; motion planning J a m m i n g l a y e r e d m e m b r a n e g r i p p e r m e c h a n i s m f o r g r a s p i n g d i f f e r e n t l y shaped-objects without excessive pushing force for search and rescue missions Masahiro Fujita∗ , Kenjiro Tadakuma∗ , Hirone Komatsu , Eri Takane , Akito Nomura , Tomoya Ichimura , Masashi Konyo and Satoshi Tadokoro Graduate S chool of I nformation S ciences, Tohoku Universit y, Aoba-ku, S endai-shi, M iyagi-ken, Japan ABSTR AC T A gripper comprising a jamming membrane was developed with the capability of grasping collapsible, soft, and fragile objects without applying heavy pressure. In disaster sites, it is necessary for robots to grab various types of objects, such as fragile objects. Deformable grippers that contain bags filled with powder cannot handle collapsible or soft objects without excessive pressure. Changing powder density relatively by changing inner volume is one approach to overcome this problem. By expanding the concept and simplifying the variable inner volume of the gripping mechanism, we developed a jamming membrane comprising the following three layers: outer layer and inner layer made of rubber and a powder layer in between the outer and inner rubber layer. This jamming membrane allows collapsible, soft, or fragile objects to be held securely without applying too much pressure. We designed and developed a prototype of the jamming membrane gripper. Our experiments confirmed the validity of the proposed jamming membrane mechanism. KEY WORDS Jamming membrane; variable inner volume mechanism; jamming transition; rescue