435 research outputs found
Motion control of a snake robot moving between two non-parallel planes
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 robot’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
Macro-continuous dynamics for hyper-redundant robots: application to locomotion bio-inspired by elongated animals
International audienceThis article presents a unified dynamic modeling approach of continuum robots. The robot is modeled as a geometrically exact beam continuously actuated through an active strain law. Once included into the geometric mechanics of locomotion, the approach applies to any hyper-redundant or continuous robot devoted to manipulation and/or locomotion. Furthermore, exploiting the nature of the resulting models as being a continuous version of the Newton-Euler models of discrete robots, an algorithm is proposed which is capable of computing the internal control torques (and/or forces) as well as the rigid overall motions of the locomotor robot. The efficiency of the approach is finally illustrated through many examples directly related to the terrestrial locomotion of elongated animals as snakes, worms or caterpillars and their associated bio-mimetic artifacts
Mechanical Design and Dynamic Analysis of Pipe Crawling Robot for Internal Gas Pipeline Inspection
Pipelines play an important role in terms of transporting various types of fluid like liquid and gas. They are mainly used not only in small applications like housing area, but also in large industrial field like in an oil and gas field. Maintenance of these pipelines is crucial and the cost of doing it continues to increase from time to time and thus a new approach is needed in order to tackle these problems. This project report presents the design and development of crawling robots for internal pipe inspection. There are four designs being considered but this paper will present the simplest of the design which is the wheeled type design that with a pantograph mechanism with a sliding base that allows folding and unfolding of the robot’s legs. The mechanism of this robot is based on the design of MRINSPECT III and the driving mechanism of MRINSPECT IV. The robot is designed accordingly so that it can function through a pipeline ranging from 6 inches diameter to 10 inches diameter. The design is then modeled and simulated using AutoCAD and ADAMS respectively
Approximate Path-Tracking Control of Snake Robot Joints With Switching Constraints
This paper presents an approximate path-tracking control method for all joints of a snake robot, along with the verification of this method by simulations and experiments. We consider a wheeled snake robot that has passive wheels and active joints. The robot can switch the wheels that touch the ground by lifting the required parts of its body. The model of the robot becomes a kinematically redundant system if certain wheels are lifted. Using this kinematic redundancy, and selecting the appropriate lifted parts, we design a controller for approximate path tracking. Simulations and experimental results show that the proposed controller effectively reduces the path-tracking error for all joints of the snake robot
Bio-Inspired Robotics
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 sensory–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
Space-Capable Long and Thin Continuum Robotic Cable
Design of continuum robots, i.e. robots with continuous backbones, has been an active area of research in robotics for minimally invasive surgery, search and rescue, object manipulation, etc. Along the same lines, NASA developed Tendril , the first long and thin continuum robot of its kind, intended for in-space inspection applications.
The thesis starts with describing and discussing the key disadvantages of the current state of the art mechanical design of Tendril\u27\u27 producing undesirable effects during operation. It then includes the design specifics of a novel concept for construction of a next generation long and thin, space-cable, multi-section, continuum cable-like robot, with a modified mechanical design for better performance. The new design possesses key features including controllable bending along its entire length, local compression and a compact actuation package. This new design is detailed in two versions. The first is a planar variant (suited for a 2D workspace), explaining the principle which allows the cable robot to achieve the above mentioned features. It is followed by a refined spatial version (suited for 3D workspace), where the functional characteristics are achieved within the desired aspect ratio of thin (less than 1 cm diameter) and relatively longer length (more than 100 cm) of the robotic cable.
A new forward kinematic model is then developed extending the established models for constant-curvature continuum robots, to account for the new design feature of controllable compression (in the hardware) and is validated by performing experiments with the robot in (2D) planar and (3D) spatial scenarios. This new model is found to be effective as a baseline to predict the performance of such a long and thin continuum cable\u27\u27 robot
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