A Mobile Quad-Arm Robot ARMS: Wheel-Legged Tripedal Mobility and Quad-Arm Manipulation

This letter proposes a mobile quad-arm robot: ARMS that unifies wheel-legged tripedal mobility, wheeled mobility, and quad-arm manipulation. The four arms have different mechanics and are designed to be general-purpose arms to enable the wheel-legged hybrid mobilities and manipulation. The three-degree-of-freedom (DOF) front arm has an active wheel, which is used for wheel-legged tripedal walking and wheel driving with passive wheels attached to the torso. The three-DOF rear arms are series elastic arms, which are used for wheel-legged tripedal walking, object grasping, and manipulation. The two-DOF upper arm is used for manipulation only; its position and orientation are determined by coordinating all arms. Each motor is controlled by an angle controller and trajectory modification with angle, angular velocity, angular acceleration, and torque constraints. ARMS was experimentally validated on the basis of the following four tasks: wheel-legged walking, wheel-driving, wheel-driving with grasping, and carrying a bag

Single-Loop Full R Joints of Multi-Mode Omnidirectional Ground Mobile Robot

In order to solve the problem of loss of locomotion ability due to overturning and instability during the movement of a mobile robot, a multi-mode omnidirectional ground mobile robot with a deformable structure is proposed. Single-loop is used as the unit, and the three-direction geometric deformation can be realized by controlling its R joints in time sharing. The 4-RRRRRR parallel mobile robot formed by two closed-loops orthogonally has four different rolling modes, and each mode can be switched between each other. Once the robot is overturned and unstable during the movement, it can be deformed into other modes and continue to move. After the description of the robot, the DOF (degree-of-freedom) is calculated based on the screw theory. Gait planning and locomotion feasibility analysis indicate that the robot can realize four locomotion modes and their mutual switching. Finally, the simulations and prototype experiments are presented to verify the feasibility of the different locomotion modes and the ability of the obstacle crossing

ShapeBots: Shape-changing Swarm Robots

We introduce shape-changing swarm robots. A swarm of self-transformable robots can both individually and collectively change their configuration to display information, actuate objects, act as tangible controllers, visualize data, and provide physical affordances. ShapeBots is a concept prototype of shape-changing swarm robots. Each robot can change its shape by leveraging small linear actuators that are thin (2.5 cm) and highly extendable (up to 20cm) in both horizontal and vertical directions. The modular design of each actuator enables various shapes and geometries of self-transformation. We illustrate potential application scenarios and discuss how this type of interface opens up possibilities for the future of ubiquitous and distributed shape-changing interfaces.Comment: UIST 201

Optimal design and experimental verification of a spherical-wheel composite robot with automatic transformation system

This paper presents a design for a dual-mode prototype robot with the advantages of both a spherical robot and wheeled robot. A spherical robot has flexible movement capabilities, and the spherical shell can protect the mechanism and electronic devices. A wheeled mobile robot operates at high speed on a flat road. Its simple structure and control system has made it a popular choice in the field of robotics. Our objective was to develop a new concept robot capable of combining two different locomotion mechanisms to increase the locomotion stability and efficiency. The proposed mobile robot prototype was found to be capable and suitable in different situations. The exchange of modes between the spherical and the wheeled robot was realized by a structural change of the robot. The spherical-wheel mobile robot prototype is composed of a deformable spherical shell system, the propulsion system for the sphere and a wheeled mobile unit module. The exchange of locomotion modes was implemented by changing the geometric structure of spherical shell. The mechanical structure of the composite robot is presented in detail as well as the control system including hardware components and the software. The control system allowed for the automatic transformation of the composite robot between either of the locomotion modes. Based on analysis and simulation, the mechanism was optimized in its configuration and dimension to guarantee that robot had a compact structure and high efficiency. Finally, the experimental results of the transformation and motion processes provided dynamic motion parameters and verified the feasibility of the robot prototype

Static Balancing of Wheeled-legged Hexapod Robots

Locomotion over different terrain types, whether flat or uneven, is very important for a wide range of service operations in robotics. Potential applications range from surveillance, rescue, or hospital assistance. Wheeled-legged hexapod robots have been designed to solve these locomotion tasks. Given the wide range of feasible operations, one of the key operation planning issues is related to the robot balancing during motion tasks. Usually this problem is related with the pose of the robot’s center of mass, which can be addressed using different mathematical techniques. This paper proposes a new practical technique for balancing wheeled-legged hexapod robots, where a Biodex Balance System model SD (for static & dynamic) is used to obtain the effective position of the center of mass, thus it can be recalculated to its optimal position. Experimental tests are carried out to evaluate the effectiveness of this technique and modify and improve the position of hexapod robots’ center of mass

Design and Development of Climbing Robotic Systems for Automated Inspection of Steel Structures and Bridges

Steel structures are indispensable parts of modern civilization, with typical civil infrastructures including bridges, wind turbines, electric towers, oil rigs, ships, and submarines, all made of steel. These structures require frequent maintenance to ensure safety and longevity. Steel bridges are the most challenging architectures due totheir complexity and height. Most inspections are conducted manually by professional human inspectors with special devices to inspect visible damages and defects on or inside these structures. However, this procedure is usually highly time-consuming, costly, and risky. Automated solutions are desired to address this problem. However, arduous engineering is delaying progress. A complete system needs to deal with three main problems: (1) locomotive performance for the high complexity of steel bridges, including differential curvatures, transitions between beams, and obstacles; (2) data collection capability, inclusive of visible and invisible damages, in-depth information such as vibration, coat, and material thickness, etc.; and (3) working conditions made up of gust winds. To achieve such a complete system, this dissertation presents novel developments of inspection-climbing robots. Five different robot versions are designed to find the simplest and most effective configuration as well as control manner. Our approach started with (1) a transformable tank-like robot integrated with a haptic device and ii two natural-inspired locomotion, (2) a roller chain-like robot, (3) a hybrid worming mobile robot, (4) a multi-directional bicycle robot, and (5) an omni-directional climbing Robot, identified as the most potential solution for automated steel bridge inspection. For each robotic development, detailed mechanical analysis frameworks are presented. Both lab tests and field deployments of these robotic systems have been conducted to validate the proposed designs

A reconfigurable hybrid wheel-track mobile robot based on Watt II six-bar linkage

This paper presents the design and development of a novel reconfigurable hybrid wheel-track mobile robot (RHMBot). This new reconfigurable mobile robot is constructed based on a Watt II six-bar linkage; through structure reconfiguration, it can provide three locomotion modes as wheel mode, tracked mode, and climbing and roll-over mode. Mechanical design of the proposed RHMBot is introduced, and using mechanism decomposition kinematics of the reconfigurable frame is investigated. Locomotion of the robot is then interpreted associated with transformation of the reconfigurable frame. Further, deformation of the deformable track belt is characterized and static analysis of the reconfigurable frame is accomplished. Numerical simulation of the proposed reconfigurable frame is subsequently implemented, integrated with driving-torque associated parametric study, leading to optimization of the structure parameters. Consequently, prototype of the proposed RHMBot is designed and developed; exploiting which a series of field tests are conducted verifying feasibility and manoeuvrability of the proposed multi-locomotion mobile robot

변신 바퀴를 이용한 다중 지형 이동 로봇의 설계

학위논문 (석사)-- 서울대학교 대학원 : 기계항공공학부, 2014. 2. 주종남.In this paper, the design, optimization, and performance evaluation of a new wheel-leg hybrid robot are reported. This robot utilizes a novel kind of transformable wheel for its locomotion to combine the advantages of both circular wheels and legged wheels. To minimize design complexity, this new transformable wheels transformation process is operated passively, which eliminates the need for additional actuators. A new triggering mechanism is also employed to increase the success rate of the transformation. To maximize the climbing ability in the legged-wheel mode, the design parameters of the transformable wheel and the robot are tuned based on behavioral analyses. The performance of our new development is evaluated in terms of stability, energy efficiency, and the maximum height of the obstacle the robot can climb over. By virtue of this transformable wheel, the system could climb over an obstacle 3.25 times as tall as its wheel radius, not compromising its driving ability at 2.4 body lengths per second with the specific resistance of 0.7 on flat surfaces.Abstract Contents List of Figures & Tables 1. Introduction 2. Design of the passive transformable wheel 2.1 Components design for coupled legs 2.2 Transformation mechanism 2.3 Triggering mechanism 2.4 Climbing scenario 3. Design optimization 3.1 Modeling of the passive transformable wheel 3.2 Maximizing the transformation ratio 3.3 Foot design for the higher success rate of the transformation 4. Design of the robotic platform 4.1 Features 4.2 Tuning design parameters for stable climbing 5. Results 5.1 Speed & specific resistance 5.2 Obstacle climbing 5.3 Discussion about mode switch 6. Conclusions References 국문초록Maste