A constrained maximization formulation to analyze deformation of fiber reinforced elastomeric actuators

Singh, Govindra; Krishnan, Girish

doi:10.1088/1361-665x/aa6dc6

Cited by 40 publications

(32 citation statements)

References 17 publications

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“…Depending on number of fibers and their relative angles, FREEs can generate contraction, extension, rotation, bending, or a combination of these motions. For information regarding the fabrication of FREEs, refer to [32]. As the name suggests, the BR 2 has one bending and two rotating actuators that work in tandem to achieve complex 3D spatial motions.…”

Section: System Architecture a Br 2 Soft Robotic Manipulator Chamentioning

confidence: 99%

Open Loop Position Control of Soft Continuum Arm Using Deep Reinforcement Learning

Satheeshbabu

Uppalapati

Chowdhary

et al. 2019

2019 International Conference on Robotics and Automation (ICRA)

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Soft robots undergo large nonlinear spatial deformations due to both inherent actuation and external loading. The physics underlying these deformations is complex, and often requires intricate analytical and numerical models. The complexity of these models may render traditional modelbased control difficult and unsuitable. Model-free methods offer an alternative for analyzing the behavior of such complex systems without the need for elaborate modeling techniques. In this paper, we present a model-free approach for open loop position control of a soft spatial continuum arm, based on deep reinforcement learning. The continuum arm is pneumatically actuated and attains a spatial workspace by a combination of unidirectional bending and bidirectional torsional deformation. We use Deep-Q Learning with experience replay to train the system in simulation. The efficacy and robustness of the control policy obtained from the system is validated both in simulation and on the continuum arm prototype for varying external loading conditions.

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Section: System Architecture a Br 2 Soft Robotic Manipulator Chamentioning

confidence: 99%

Open Loop Position Control of Soft Continuum Arm Using Deep Reinforcement Learning

Satheeshbabu

Uppalapati

Chowdhary

et al. 2019

2019 International Conference on Robotics and Automation (ICRA)

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“…In this paper, we conceptualize a soft continuum manipulator as a parallel combination of soft pneumatic building blocks known as FREEs. FREEs are hollow cylindrical elastomeric membranes with two families of fibers wrapped on the surface at angles α and β with respect to its longitudinal axis [12], [28], [29] as shown in Fig. 2.…”

Section: Working Principle Of Asymmetric Manipulatorsmentioning

confidence: 99%

“…The deformation patterns are determined by fiber angles. The fabrication methodology of FREEs is detailed in the authors' previous publications [28], [31]. The BR 2 manipulator consists of three FREEs, one extending FREE denoted by B, and two rotating FREEs denoted by R (one rotating clockwise and the other counterclockwise).…”

Section: Working Principle Of Asymmetric Manipulatorsmentioning

confidence: 99%

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Design of Soft Continuum Manipulators Using Parallel Asymmetric Combination of Fiber Reinforced Elastomers

Uppalapati¹,

Krishnan²

2018

Preprint

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Soft continuum manipulators have large workspace, dexterity and adaptability, but at the cost of complex design construction highlighted by concatenating several individually controlled serial segments. In this paper, we propose a new designarchitecture for a soft continuum manipulator composed of a parallel combination of pneumatic actuators. The BR2 manipulator, featured in this paper is asymmetric as it combines one soft bending (B) actuator and two soft rotating (R2) actuators, as opposed to state of the art symmetric architectures that adopt bending segments. Spatial deformation modes are achieved by combining curvature and torsion of the individual actuators. This paper formulates a forward analysis method based on Cosserat rod mechanics to predict the spatial deformation of the manipulator under the effect of external loads with an accuracy less than 9 % of the manipulator length. The model takes into account ‘the coupling effect’ inherent to the asymmetric combination, where pressurizing the rotating actuator attenuates the bendingcurvature and vice versa. Consequently, the paper studies the optimal design of the manipulator constituents that minimize the coupling, and thus maximize the workspace and dexterity. A detailed performance study of the BR2 manipulator on aswiveling base demonstrates a spatial workspace quantified by an axisymmetric area, and sufficient dexterity such that at least 87% of the workspace can be approached with two or more orientations. These are validated through obstacle avoidance, and a pick and place task. The manipulator is also capable ofwhole arm manipulation by spiraling along cylindrical objects of varying diameters. These performance attributes surpass any other single segment module and is a potential building block for constructing customized continuum manipulators.

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“…To achieve this, advances in modeling-based tools for principled soft robot design and techniques for sensing and autonomous control of soft and continuum robots are needed. Novel pneumatic soft building blocks known as fiber-reinforced electromeric enclosures (FREEs) [43,44] have been developed to allow greater freedom in the robotic movements. FREEs are hollow cylindrical elastomeric membranes with two families of fibers wrapped on the surface at angles a and b with respect to its longitudinal axis as shown in Figure 3a,b.…”

Section: Tradeoffs In Dexterity Load Capacity and Energymentioning

confidence: 99%

Soft Robotics as an Enabling Technology for Agroforestry Practice and Research

Chowdhary

Gazzola²,

Krishnan³

et al. 2019

Sustainability

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The shortage of qualified human labor is a key challenge facing farmers, limiting profit margins and preventing the adoption of sustainable and diversified agroecosystems, such as agroforestry. New technologies in robotics could offer a solution to such limitations. Advances in soft arms and manipulators can enable agricultural robots that can have better reach and dexterity around plants than traditional robots equipped with hard industrial robotic arms. Soft robotic arms and manipulators can be far less expensive to manufacture and significantly lighter than their hard counterparts. Furthermore, they can be simpler to design and manufacture since they rely on fluidic pressurization as the primary mechanisms of operation. However, current soft robotic arms are difficult to design and control, slow to actuate, and have limited payloads. In this paper, we discuss the benefits and challenges of soft robotics technology and what it could mean for sustainable agriculture and agroforestry.

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A constrained maximization formulation to analyze deformation of fiber reinforced elastomeric actuators

Cited by 40 publications

References 17 publications

Open Loop Position Control of Soft Continuum Arm Using Deep Reinforcement Learning

Open Loop Position Control of Soft Continuum Arm Using Deep Reinforcement Learning

Design of Soft Continuum Manipulators Using Parallel Asymmetric Combination of Fiber Reinforced Elastomers

Soft Robotics as an Enabling Technology for Agroforestry Practice and Research

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