The bow leg hopping robot

Brown, Bryan L.; Zeglin, Garth

doi:10.1109/robot.1998.677072

Cited by 110 publications

(55 citation statements)

References 32 publications

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“…This simple model effectively describes the locomotion of a great variety of different animals (including humans) that use running and hopping gaits [34], and has been successfully translated into several robotic prototypes. Straightforward replicas of compressible legs have employed pneumatic elements [35] or elastic springs [36,37], whereas more elaborate designs have used flexible structural elements [38,39], a C-shaped foot [40,41], bow-like legs [42] or springs that mimic muscle-tendon systems [43]. Similar to multi-legged animals [34], multi-legged robots could base their locomotion on the SLIP model by considering the equivalent contribution of parallel springs [44], so that the system is considered to have a single virtual leg.…”

Section: Legged Locomotion: Hopping Running and Walkingmentioning

confidence: 99%

Fundamentals of soft robot locomotion

Calisti

Picardi

Laschi

2017

J. R. Soc. Interface.

244

147

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Soft robotics and its related technologies enable robot abilities in several robotics domains including, but not exclusively related to, manipulation, manufacturing, human -robot interaction and locomotion. Although field applications have emerged for soft manipulation and human-robot interaction, mobile soft robots appear to remain in the research stage, involving the somehow conflictual goals of having a deformable body and exerting forces on the environment to achieve locomotion. This paper aims to provide a reference guide for researchers approaching mobile soft robotics, to describe the underlying principles of soft robot locomotion with its pros and cons, and to envisage applications and further developments for mobile soft robotics.

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Section: Legged Locomotion: Hopping Running and Walkingmentioning

confidence: 99%

Fundamentals of soft robot locomotion

Calisti

Picardi

Laschi

2017

J. R. Soc. Interface.

244

147

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“…Another milestone in single-legged dynamic locomotion is the bow leg hopping robot developed by Garth Zeglin and Ben Brown at CMU [4] [3].…”

Section: Continuous Motion Hoppersmentioning

confidence: 99%

Control strategies for a multi-legged hopping robot

Luders

Apostolopoulos

Wettergreen

2008

2008 IEEE/RSJ International Conference on Intelligent Robots and Systems

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In this dissertation, we develop locomotion control strategies for a novel multi-legged spherical robot. The conceptual robot, named Robotic AllTerrain Surveyor (RATS), has a spherical body roughly the size of a soccer ball, with 12 legs equally distributed over its surface. The legs are pneumatic linear actuators, which are oriented such that their axes of motion are normal to the surface of the sphere. The objective of this robot is to be capable to circumvent complex obstacles and traps through rough terrain. The 12-legged spherical version of the robot is still on its design phase and no prototype has been built yet. Instead, a simpler planar prototype of the robot is available to study the control problem. The planar robot consists of a wheel with 5 legs pointing radially, that rotates freely over the main axis of a radius arm that constraints its motion into a plane. The air-cylinders run on compressed air which is supplied over a tether that goes through the radius arm.This work presents novel control strategies for the RATS planar robotic platform, which consist in the development of running and jumping gaits.The controls solutions presented were developed using two approaches: (1) conventional "hand-coded" controls, based on intuition and knowledge of the device; and (2) reinforcement learning techniques, where a policy is learned actively by maximizing the cumulative reward from a predefined reward function using value iteration. Simulators of the planar and spherical robots were implemented as tools to help the development process.This dissertation also includes an overview of the control problem for the spherical robot. Results for this section are presented only using simulation. AcknowledgementsI would like to especially thank my advisor David Wettergreen for his continuous support, including many insightful conversations during the development of the ideas in this thesis, and for helpful comments on the text. I thank Professor Dimi Apostolopoulos for agreeing to let me to participate in the project from which this work is derived in the first place, and also for his exceptional guidance during all the process. Haynes for his great insights about the control strategies.

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“…James Schmiedeler designed the OSU DASH (Dynamic Articulated Structure for High performance) leg [11] [12], based on work done by Brown and Zeglin [13] and others [14][15] [16]. The Stanford DASH leg, the second prototype, was developed at Stanford University (Fig.…”

Section: Single Legmentioning

confidence: 99%

System Design of a Quadrupedal Galloping Machine

Nichol¹,

Singh

Waldron

et al. 2004

The International Journal of Robotics Research

104

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Abstract-Ohio State and Stanford Universities are cooperating to construct and artificial quadruped. This quadruped has a rest leg length of 0.68m and weighs 70kg. The body is made of four single-leg modules. Each module houses an articulated 3-dof leg. The articulated leg structure uses a set of mechanical springs to store energy. The stiffness of the leg, from hip to foot, is highly nonlinear. The leg initially stiffens as the leg is compressed the first 1/3 of its range, then remains roughly constant for the remainder. This stiffening allows the leg to maintain a relatively constant working length. A cable is used to flex the knee of the quadruped. As the cable is pulled, the knee bends, tensioning the energy storage springs. This cable makes about a ¼ turn over a pulley which is concentric with the hip axis, ½ turn around a pulley at the ankle and then ¾ turn back around a second hip pulley in a direction opposite the first hip pulley. This arrangement decouples cable tension and hip torque. The non-anchored end of the cable is tensioned by a capstan. This capstan uses unique geometry to decrease holding torque and to release the cable instantly. The current top speed of this leg in a 2-dimensional test is 4.15m/s. This leg has been controlled using two control systems, both implemented on an embedded controller attached to the leg. An articulated leg presents control challenges not seen when trying to control a prismatic leg. The first controller tested is a heuristic algorithm whose parameters are updated in real time by the LevenbergMarquardt learning method. This controller is similar to the controllers used by Raibert[24], with modifications to allow for leg asymmetry. The second controller tested is a direct adaptive fuzzy controller. The fuzzy controller consists of a rule base, inference mechanism, fuzzification interface, and defuzzification interface. Fuzzification starts by mapping an input (body velocity, desired change in velocity, height) into one or more membership functions.The inference mechanism then determines the applicability of each rule to the current inputs. Defuzzification combines the recommendations of each rule in an output based upon rule certainties. The adaptation mechanism modifies the rule output centers to correct velocity errors. The adaptation mechanism gains are experimentally tuned. Once tuned, the controller quickly adapts to leg changes. Both control systems were tested with and without adaptation. Both systems more accurately tracked desired velocity with adaptation. Accurate, high resolution, high speed body attitude sensing is essential for successful quadruped operation.No existing solutions meet the project requirements. An adequate sensor system is being developed in cooperation with a commercial vendor. Initial results show that accurate position tracking is possible with currently available MEMS inertial sensors.

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The bow leg hopping robot

Cited by 110 publications

References 32 publications

Fundamentals of soft robot locomotion

Fundamentals of soft robot locomotion

Control strategies for a multi-legged hopping robot

System Design of a Quadrupedal Galloping Machine

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