Kinematic reconfigurability control for an environmental mobile robot operating in the Amazon rain forest

Freitas, Gustavo; Gleizer, Gabriel de Albuquerque; Lizarralde, Fernando; Hsu, Liu; Reis, Ney Robinson Salvi dos

doi:10.1002/rob.20334

“…Our next steps include: (1) implement and test a mobility methodology that optimizes vehicle stability and force distribution by actively controlling each leg's height and angle [5,4]; (2) develop and test methods to adjust wheel-surface contact angle-and consequently the velocity-torque relationship-to control robot speed while minimizing power consumption and avoiding motor saturation [2]; and (3) continue deployment in the Amazon region. Based on field results we will determine the need to implement a more complex control method that explicitly takes into account modeling uncertainties and external disturbances.…”

Section: Resultsmentioning

confidence: 99%

“…The former stems from the fact that p 0wy directly determines the robot's orientation, force distribution among legs, and tip-over stability [5,4]; and the latter from the fact that it directly determines the velocity-torque relationship by changing the effective wheel radius. In other words, the control objectives are to:…”

Section: Ehr Leg Kinematic Controlmentioning

confidence: 99%

Design, Modeling, and Control of a Wheel-Legged Locomotion System for the Environmental Hybrid Robot

Freitas¹,

Lizarralde²,

Hsu³

et al. 2011

Biomechanics / 752: Robotics

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Urucu, deep in the Amazon forest, is the largest in-land natural gas and oil producing site in Brazil. The oil and gas extracted in Urucu travel some 700 km in a pipeline through the jungle until they reach Manaus, where they are refined and consumed. Exploration of the site is conditioned on the Brazilian oil company Petrobras monitoring a 400 km section of the pipeline for any signs of water contamination. The Environmental Hybrid Robot (EHR) was conceived to automate this humongous monitoring task, currently executed in extremely small scale by scientists and locals on foot and small boats. This paper describes the design, analysis, and testing of the EHR's second-generation locomotion mechanism, based on a two-DOF parallel mechanism. The new mechanism allows for independent control of wheel position and orientation relative to the terrain, thus significantly increasing the robot's mobility. Additionally, it allows for control of the vehicle's velocity-torque curve by adjusting the radius of curvature of the wheel at the point of contact with the soil. We present the forward and differential kinematic models of the new mechanism and, based on them, a differential kinematics-based position and orientation control method. We illustrate the methodology with experimental results.

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“…It is worth mentioning that the methodology presented in this section 3 is implemented in the suspension control system of the Environmental Hybrid Robot, recently developed by CENPES/Petrobras, which is an amphibious 4-wheel-legged robot composed by a planar parallel mechanism in each suspension (Freitas et al, 2010). Some research topics, applied to redundant manipulators and parallel robots, that can be investigated following the ideas presented in this work are: to consider the dynamic control problem for these mechanisms, relax the assumption of the robot kinematics to be fully known and develop a strategy for singularity and obstacle avoidance.…”

Section: Discussionmentioning

confidence: 99%

Kinematic control of constrained robotic systems

Freitas

¹

,

Leite

²

,

Lizarralde

³

2011

Sba Controle & Automação

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RESUMO Controle de Sistemas Robóticos com Restrições CinemáticasEste artigo considera o problema de controle de postura para sistemas robóticos com restrições cinemáti-cas. A ideia principal é considerar as restrições cinemáticas dos mecanismos a partir de suas equações estruturais, ao invés de usar explicitamente a equação de restrição. Um estudo de caso para robôs paralelos e robôs cooperativos é discutido baseado nos conceitos de cinemática direta, cinemática diferencial, singularidades e controle cinemático. Resultados de simulação, obtidos a partir de um mecanismo F our-Bar linkage, uma plataforma de Gough-Stewart planar e dois robôs cooperativos, ilustram a aplicabilidade e versatilidade da metodologia proposta.PALAVRAS-CHAVE: robôs paralelos, robôs redundantes, coordenação multi-rôbos, singularidades cinemáticas . ABSTRACTThis paper addresses the posture control problem for robotic systems subject to kinematic constraints. The key idea is to consider the kinematic constraints of the mechanisms from their structure equations, instead of explicitly using the constraint equations. A case study for parallel robots and cooperating redundant robots is discussed based on the following concepts: forward kinematics, differential kinematics, singularities and kinematic control. Simulations results, obtained with a Four-Bar linkage mechanism, a planar Gough-Stewart platform and two cooperating robots, illustrate the applicability and versatility of the proposed methodology.

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“…This mechanism has one DOF; therefore, when the coupled motor is actuated, both the position and the angle of the wheel relative to the terrain are affected. By commanding the wheel's height, it is possible to modify the system's stability and force distribution among the legs [6,5]. The suspension angle also influences the contact point with the terrain and consequently the effective radius of the spherical wheels.…”

Section: Locomotion System Initial Designmentioning

confidence: 99%

Design, Modeling, and Control of a Wheel-Legged Locomotion System for the Environmental Hybrid Robot

Freitas¹,

Lizarralde²,

Hsu³

et al. 2012

Biomechanics / 752: Robotics

Self Cite

View full text Add to dashboard Cite

Urucu, deep in the Amazon forest, is the largest in-land natural gas and oil producing site in Brazil. The oil and gas extracted in Urucu travel some 700 km in a pipeline through the jungle until they reach Manaus, where they are refined and consumed. Exploration of the site is conditioned on the Brazilian oil company Petrobras monitoring a 400 km section of the pipeline for any signs of water contamination. The Environmental Hybrid Robot (EHR) was conceived to automate this humongous monitoring task, currently executed in extremely small scale by scientists and locals on foot and small boats. This paper describes the design, analysis, and testing of the EHR's second-generation locomotion mechanism, based on a two-DOF parallel mechanism. The new mechanism allows for independent control of wheel position and orientation relative to the terrain, thus significantly increasing the robot's mobility. Additionally, it allows for control of the vehicle's velocity-torque curve by adjusting the radius of curvature of the wheel at the point of contact with the soil. We present the forward and differential kinematic models of the new mechanism and, based on them, a differential kinematics-based position and orientation control method. We illustrate the methodology with experimental results.

show abstract

Kinematic reconfigurability control for an environmental mobile robot operating in the Amazon rain forest

Cited by 33 publications

References 25 publications

Design, Modeling, and Control of a Wheel-Legged Locomotion System for the Environmental Hybrid Robot

Design, Modeling, and Control of a Wheel-Legged Locomotion System for the Environmental Hybrid Robot

Kinematic control of constrained robotic systems

Design, Modeling, and Control of a Wheel-Legged Locomotion System for the Environmental Hybrid Robot

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