32 research outputs found

    Range-Sensor-Based Semiautonomous Whole-Body Collision Avoidance of a Snake Robot

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    This brief presents a control system for a snake robot based on range sensor data that semiautonomously aids the robot in avoiding collisions with obstacles. In the proposed system, an operator indicates the desired velocity of the first link of the robot using a joystick, and the joint input which accomplishes both the desired velocity of the first link and collision avoidance between subsequent links and obstacles is automatically calculated by the controller, which selects the links needed to be grounded and exploits redundancy. The controller uses real-time data from range sensors for obstacle positions. The experimental system, which has range sensors and the function generating environmental map using simultaneous localization and mapping, was developed with decreasing calculation cost, and experiments were performed to verify the effectiveness of the proposed system in unknown environments

    Development and Control of Articulated Mobile Robot for Climbing Steep Stairs

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    In this paper, we develop an articulated mobile robot that can climb stairs, and also move in narrow spaces and on 3-D terrain. This paper presents two control methods for this robot. The first is a 3-D steering method that is used to adapt the robot to the surrounding terrain. In this method, the robot relaxes its joints, allowing it to adapt to the terrain using its own weight, and then, resumes its motion employing the follow-the-leader method. The second control method is the semi-autonomous stair climbing method. In this method, the robot connects with the treads of the stairs using a body called a connecting part, and then shifts the connecting part from its head to its tail. The robot then uses the sensor information to shift the connecting part with appropriate timing. The robot can climb stairs using this method even if the stairs are steep, and the sizes of the riser and the tread of the stairs are unknown. Experiments are performed to demonstrate the effectiveness of the proposed methods and the developed robot

    Motion control of a snake robot moving between two non-parallel planes

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    A control method that makes the head of a snake robot follow an arbitrary trajectory on two non-parallel planes, including coexisting sloped and flat planes, is presented. We clarify an appropriate condition of contact between the robot and planes and design a controller for the part of the robot connecting the two planes that satisfies the contact condition. Assuming that the contact condition is satisfied, we derive a simplified model of the robot and design a controller for trajectory tracking of the robotโ€™s head. The controller uses kinematic redundancy to avoid violating the limit of the joint angle and a collision between the robot and the edge of a plane. The effectiveness of the proposed method is demonstrated in experiments using an actual robot

    Control of a snake robot for passing through a self-closing door

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    We propose the control method for a snake robot to pass through a self-closing door. The proposed method is realized by applying the two-point simultaneous control method. The position and orientation of head and tail of the robot are controlled simultaneously by using the two-point simultaneous control method. By controlling the position and orientation of the head of the robot, the robot opens the door and keeps it open. At the same time, the robot enters through the door from the tail by controlling the tail of the robot simultaneously. The robot passes through the door by pushing away the side of the door with the body. The proposed method enables the robot to enter the interior separated by a door and contributes to the expansion of the activity environment for snake robots. The experimental result validates the proposed methods

    Three-dimensional steering for an articulated mobile robot with prismatic joints with consideration of hardware limitations

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    The paper presents a three-dimensional steering method for an articulated mobile robot that contains links, rotational joints, prismatic joints, and active wheels. The robot can change the angles of its links using the rotational joints and vary the lengths of its links using the prismatic joints. The target motion of this robot is represented by a continuous curve and the motions of the joints and the wheels are calculated by fitting the entire robot to this target curve. The forward velocity of the robot\u27s head is adjusted to satisfy the hardware limitations of the robot; e.g. joint angle, joint velocity, and wheel velocity limitations. In addition, a terrain-following method is presented that considers the changes in the lengths of the links. An experimental articulated mobile robot was developed and experiments were carried out to demonstrate the effectiveness of the proposed method

    ๋ถ„์‚ฐ๋œ ๋กœํ„ฐ๋กœ ๊ตฌ๋™๋˜๋Š” ๋น„ํ–‰ ์Šค์ผˆ๋ ˆํ†ค ์‹œ์Šคํ…œ์˜ ๋””์ž์ธ ์ƒํƒœ์ถ”์ • ๋ฐ ์ œ์–ด

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    ํ•™์œ„๋…ผ๋ฌธ(๋ฐ•์‚ฌ)--์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› :๊ณต๊ณผ๋Œ€ํ•™ ๊ธฐ๊ณ„ํ•ญ๊ณต๊ณตํ•™๋ถ€,2020. 2. ์ด๋™์ค€.In this thesis, we present key theoretical components for realizing flying aerial skeleton system called LASDRA (large-size aerial skeleton with distributed rotor actuation). Aerial skeletons are articulated aerial robots actuated by distributed rotors including both ground connected type and flying type. These systems have recently attracted interest and are being actively researched in several research groups, with the expectation of applying those for aerial manipulation in distant/narrow places, or for the performance with entertaining purpose such as drone shows. Among the aerial skeleton systems, LASDRA system, proposed by our group has some significant advantages over the other skeleton systems that it is capable of free SE(3) motion by omni-directional wrench generation of each link, and also the system can be operated with wide range of configuration because of the 3DOF (degrees of freedom) inter-link rotation enabled by cable connection among the link modules. To realize this LASDRA system, following three components are crucial: 1) a link module that can produce omni-directional force and torque and enough feasible wrench space; 2) pose and posture estimation algorithm for an articulated system with high degrees of freedom; and 3) a motion generation framework that can provide seemingly natural motion while being able to generate desired motion (e.g., linear and angular velocity) for the entire body. The main contributions of this thesis is theoretically developing these three components, and verifying these through outdoor flight experiment with a real LASDRA system. First of all, a link module for the LASDRA system is designed with proposed constrained optimization problem, maximizing the guaranteed feasible force and torque for any direction while also incorporating some constraints (e.g., avoiding inter-rotor air-flow interference) to directly obtain feasible solution. Also, an issue of ESC-induced (electronic speed control) singularity is first introduced in the literature which is inevitably caused by bi-directional thrust generation with sensorless actuators, and handled with a novel control allocation called selective mapping. Then for the state estimation of the entire LASDRA system, constrained Kalman filter based estimation algorithm is proposed that can provide estimation result satisfying kinematic constraint of the system, also along with a semi-distributed version of the algorithm to endow with system scalability. Lastly, CPG-based motion generation framework is presented that can generate natural biomimetic motion, and by exploiting the inverse CPG model obtained with machine learning method, it becomes possible to generate certain desired motion while still making CPG generated natural motion.๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๋น„ํ–‰ ์Šค์ผˆ๋ ˆํ†ค ์‹œ์Šคํ…œ LASDRA (large-size aerial skeleton with distributed rotor actuation) ์˜ ๊ตฌํ˜„์„ ์œ„ํ•ด ์š”๊ตฌ๋˜๋Š” ํ•ต์‹ฌ ๊ธฐ๋ฒ•๋“ค์„ ์ œ์•ˆํ•˜๋ฉฐ, ์ด๋ฅผ ์‹ค์ œ LASDRA ์‹œ์Šคํ…œ์˜ ์‹ค์™ธ ๋น„ํ–‰์„ ํ†ตํ•ด ๊ฒ€์ฆํ•œ๋‹ค. ์ œ์•ˆ๋œ ๊ธฐ๋ฒ•์€ 1) ์ „๋ฐฉํ–ฅ์œผ๋กœ ํž˜๊ณผ ํ† ํฌ๋ฅผ ๋‚ผ ์ˆ˜ ์žˆ๊ณ  ์ถฉ๋ถ„ํ•œ ๊ฐ€์šฉ ๋ Œ์น˜๊ณต๊ฐ„์„ ๊ฐ€์ง„ ๋งํฌ ๋ชจ๋“ˆ, 2) ๋†’์€ ์ž์œ ๋„์˜ ๋‹ค๊ด€์ ˆ๊ตฌ์กฐ ์‹œ์Šคํ…œ์„ ์œ„ํ•œ ์œ„์น˜ ๋ฐ ์ž์„ธ ์ถ”์ • ์•Œ๊ณ ๋ฆฌ์ฆ˜, 3) ์ž์—ฐ์Šค๋Ÿฌ์šด ์›€์ง์ž„์„ ๋‚ด๋Š” ๋™์‹œ์— ์ „์ฒด ์‹œ์Šคํ…œ์ด ์†๋„, ๊ฐ์†๋„ ๋“ฑ ์›ํ•˜๋Š” ์›€์ง์ž„์„ ๋‚ด๋„๋ก ํ•  ์ˆ˜ ์žˆ๋Š” ๋ชจ์…˜ ์ƒ์„ฑ ํ”„๋ ˆ์ž„์›Œํฌ๋กœ ๊ตฌ์„ฑ๋œ๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ์šฐ์„  ๋งํฌ ๋ชจ๋“ˆ์˜ ๋””์ž์ธ์„ ์œ„ํ•ด ์ „๋ฐฉํ–ฅ์œผ๋กœ ๋ณด์žฅ๋˜๋Š” ํž˜๊ณผ ํ† ํฌ์˜ ํฌ๊ธฐ๋ฅผ ์ตœ๋Œ€ํ™”ํ•˜๋Š” ๊ตฌ์† ์ตœ์ ํ™”๋ฅผ ์‚ฌ์šฉํ•˜๊ณ , ์‹ค์ œ ์ ์šฉ๊ฐ€๋Šฅํ•œ ํ•ด๋ฅผ ์–ป๊ธฐ ์œ„ํ•ด ๋ช‡๊ฐ€์ง€ ๊ตฌ์†์กฐ๊ฑด(๋กœํ„ฐ ๊ฐ„ ๊ณต๊ธฐ ํ๋ฆ„ ๊ฐ„์„ญ์˜ ํšŒํ”ผ ๋“ฑ)์„ ๊ณ ๋ คํ•œ๋‹ค. ๋˜ํ•œ ์„ผ์„œ๊ฐ€ ์—†๋Š” ์•ก์ธ„์—์ดํ„ฐ๋กœ ์–‘๋ฐฉํ–ฅ ์ถ”๋ ฅ์„ ๋‚ด๋Š” ๊ฒƒ์—์„œ ์•ผ๊ธฐ๋˜๋Š” ESC ์œ ๋ฐœ ํŠน์ด์  (ESC-induced singularity) ์ด๋ผ๋Š” ๋ฌธ์ œ๋ฅผ ์ฒ˜์Œ์œผ๋กœ ์†Œ๊ฐœํ•˜๊ณ , ์ด๋ฅผ ํ•ด๊ฒฐํ•˜๊ธฐ ์œ„ํ•ด ์„ ํƒ์  ๋งตํ•‘ (selective mapping) ์ด๋ผ๋Š” ๊ธฐ๋ฒ•์„ ์ œ์‹œํ•œ๋‹ค. ์ „์ฒด LASDRA ์‹œ์Šคํ…œ์˜ ์ƒํƒœ์ถ”์ •์„ ์œ„ํ•ด ์‹œ์Šคํ…œ์˜ ๊ธฐ๊ตฌํ•™์  ๊ตฌ์†์กฐ๊ฑด์„ ๋งŒ์กฑํ•˜๋Š” ๊ฒฐ๊ณผ๋ฅผ ์–ป์„ ์ˆ˜ ์žˆ๋„๋ก ๊ตฌ์† ์นผ๋งŒ ํ•„ํ„ฐ ๊ธฐ๋ฐ˜์˜ ์ƒํƒœ์ถ”์ • ๊ธฐ๋ฒ•์„ ์ œ์‹œํ•˜๊ณ , ์‹œ์Šคํ…œ ํ™•์žฅ์„ฑ์„ ๊ณ ๋ คํ•˜์—ฌ ๋ฐ˜ ๋ถ„์‚ฐ (semi-distributed) ๊ฐœ๋…์˜ ์•Œ๊ณ ๋ฆฌ์ฆ˜์„ ํ•จ๊ป˜ ์ œ์‹œํ•œ๋‹ค. ๋งˆ์ง€๋ง‰์œผ๋กœ ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ์ž์—ฐ์Šค๋Ÿฌ์šด ์›€์ง์ž„์˜ ์ƒ์„ฑ์„ ์œ„ํ•˜์—ฌ CPG ๊ธฐ๋ฐ˜์˜ ๋ชจ์…˜ ์ƒ์„ฑ ํ”„๋ ˆ์ž„์›Œํฌ๋ฅผ ์ œ์•ˆํ•˜๋ฉฐ, ๊ธฐ๊ณ„ ํ•™์Šต ๋ฐฉ๋ฒ•์„ ํ†ตํ•ด CPG ์—ญ์—ฐ์‚ฐ ๋ชจ๋ธ์„ ์–ป์Œ์œผ๋กœ์จ ์ „์ฒด ์‹œ์Šคํ…œ์ด ์›ํ•˜๋Š” ์›€์ง์ž„์„ ๋‚ผ ์ˆ˜ ์žˆ๋„๋ก ํ•œ๋‹ค.1 Introduction 1 1.1 Motivation and Background 1 1.2 Research Problems and Approach 3 1.3 Preview of Contributions 5 2 Omni-Directional Aerial Robot 7 2.1 Introduction 7 2.2 Mechanical Design 12 2.2.1 Design Description 12 2.2.2 Wrench-Maximizing Design Optimization 13 2.3 System Modeling and Control Design 20 2.3.1 System Modeling 20 2.3.2 Pose Trajectory Tracking Control 22 2.3.3 Hybrid Pose/Wrench Control 22 2.3.4 PSPM-Based Teleoperation 24 2.4 Control Allocation with Selective Mapping 27 2.4.1 Infinity-Norm Minimization 27 2.4.2 ESC-Induced Singularity and Selective Mapping 29 2.5 Experiment 38 2.5.1 System Setup 38 2.5.2 Experiment Results 41 2.6 Conclusion 49 3 Pose and Posture Estimation of an Aerial Skeleton System 51 3.1 Introduction 51 3.2 Preliminary 53 3.3 Pose and Posture Estimation 55 3.3.1 Estimation Algorithm via SCKF 55 3.3.2 Semi-Distributed Version of Algorithm 59 3.4 Simulation 62 3.5 Experiment 65 3.5.1 System Setup 65 3.5.2 Experiment of SCKF-Based Estimation Algorithm 66 3.6 Conclusion 69 4 CPG-Based Motion Generation 71 4.1 Introduction 71 4.2 Description of Entire Framework 75 4.2.1 LASDRA System 75 4.2.2 Snake-Like Robot & Pivotboard 77 4.3 CPG Model 79 4.3.1 LASDRA System 79 4.3.2 Snake-Like Robot 80 4.3.3 Pivotboard 83 4.4 Target Pose Calculation with Expected Physics 84 4.5 Inverse Model Learning 86 4.5.1 LASDRA System 86 4.5.2 Snake-Like Robot 89 4.5.3 Pivotboard 90 4.6 CPG Parameter Adaptation 93 4.7 Simulation 94 4.7.1 LASDRA System 94 4.7.2 Snake-Like Robot & Pivotboard 97 4.8 Conclusion 101 5 Outdoor Flight Experiment of the F-LASDRA System 103 5.1 System Setup 103 5.2 Experiment Results 104 6 Conclusion 111 6.1 Summary 111 6.2 Future Works 112Docto

    Navigation of Automatic Vehicle using AI Techniques

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    In the field of mobile robot navigation have been studied as important task for the new generation of mobile robot i.e. Corobot. For this mobile robot navigation has been viewed for unknown environment. We consider the 4-wheeled vehicle (Corobot) for Path Planning, an autonomous robot and an obstacle and collision avoidance to be used in sensor based robot. We propose that the predefined distance from the robot to target and make the robot follow the target at this distance and improve the trajectory tracking characteristics. The robot will then navigate among these obstacles without hitting them and reach the specified goal point. For these goal achieving we use different techniques radial basis function and back-propagation algorithm under the study of neural network. In this Corobot a robotic arm are assembled and the kinematic analyses of Corobot arm and help of Phidget Control Panel a wheeled to be moved in both forward and reverse direction by 2-motor controller have to be done. Under kinematic analysis propose the relationships between the positions and orientation of the links of a manipulator. In these studies an artificial techniques and their control strategy are shown with potential applications in the fields of industry, security, defense, investigation, and others. Here finally, the simulation result using the webot neural network has been done and this result is compared with experimental data for different training pattern

    Bio-Inspired Robotics

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    Modern robotic technologies have enabled robots to operate in a variety of unstructured and dynamically-changing environments, in addition to traditional structured environments. Robots have, thus, become an important element in our everyday lives. One key approach to develop such intelligent and autonomous robots is to draw inspiration from biological systems. Biological structure, mechanisms, and underlying principles have the potential to provide new ideas to support the improvement of conventional robotic designs and control. Such biological principles usually originate from animal or even plant models, for robots, which can sense, think, walk, swim, crawl, jump or even fly. Thus, it is believed that these bio-inspired methods are becoming increasingly important in the face of complex applications. Bio-inspired robotics is leading to the study of innovative structures and computing with sensoryโ€“motor coordination and learning to achieve intelligence, flexibility, stability, and adaptation for emergent robotic applications, such as manipulation, learning, and control. This Special Issue invites original papers of innovative ideas and concepts, new discoveries and improvements, and novel applications and business models relevant to the selected topics of ``Bio-Inspired Robotics''. Bio-Inspired Robotics is a broad topic and an ongoing expanding field. This Special Issue collates 30 papers that address some of the important challenges and opportunities in this broad and expanding field
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