Kinematics and statics of eccentric soft bending actuators with external payloads

Yang, Chenghao; Kang, Rongjie; Branson, David T.; Chen, Lisha; Dai, Jian S.

doi:10.1016/j.mechmachtheory.2019.05.015

Cited by 44 publications

(16 citation statements)

References 49 publications

(58 reference statements)

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“…If external forces are negligible, the kinematic model can be further simplified by introducing the assumption of constant curvature (CC) or piece-wise constant curvature (PCC) so that the configuration of the manipulator can be uniquely defined by a reduced number of DOFs. Alternative quasi-static approaches that do not rely on CC or PCC assumptions include fast finite element methods [27], screw theory [43], and Cosserat rod theory [3]. Conversely, a dynamical model of the system is necessary for control purposes in case of fast movements [40], and model reduction techniques are required to render the control problem tractable.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear energy-based control of soft continuum pneumatic manipulators

et al. 2021

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This paper investigates the model-based nonlinear control of a class of soft continuum pneumatic manipulators that bend due to pressurization of their internal chambers and that operate in the presence of disturbances. A port-Hamiltonian formulation is employed to describe the closed loop system dynamics, which includes the pressure dynamics of the pneumatic actuation, and new nonlinear control laws are constructed with an energy-based approach. In particular, a multi-step design procedure is outlined for soft continuum manipulators operating on a plane and in 3D space. The resulting nonlinear control laws are combined with adaptive observers to compensate the effect of unknown disturbances and model uncertainties. Stability conditions are investigated with a Lyapunov approach, and the effect of the tuning parameters is discussed. For comparison purposes, a different control law constructed with a backstepping procedure is also presented. The effectiveness of the control strategy is demonstrated with simulations and with experiments on a prototype. To this end, a needle valve operated by a servo motor is employed instead of more sophisticated digital pressure regulators. The proposed controllers effectively regulate the tip rotation of the prototype, while preventing vibrations and compensating the effects of disturbances, and demonstrate improved performance compared to the backstepping alternative and to a PID algorithm.

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Section: Introductionmentioning

confidence: 99%

Nonlinear energy-based control of soft continuum pneumatic manipulators

et al. 2021

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“…11b, the strain obtained in this test is then less than 7%. Note that within this range (generally the strain within 0-1), the stress and strain relationship in hyperelastic materials such as this type of silicon rubber, is almost linear and it can be expressed by Young's modulus [32][33][34]. The large deformation experienced by our surface is in the overall shape and spatial movement of the points across the surface that leads to considerable overall relative bending.…”

Section: Test Rigmentioning

confidence: 92%

“…13 and Fig. 14, we may consider our surface to have very small elastic strain for its given material [32][33][34].…”

Section: Test Rigmentioning

confidence: 99%

A Lumped-Mass Model for Large Deformation Continuum Surfaces Actuated by Continuum Robotic Arms

Habibi

Yang

Godage

et al. 2019

Journal of Mechanisms and Robotics

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Currently, flexible surfaces enabled to be actuated by robotic arms are experiencing high interest and demand for robotic applications in various areas such as healthcare, automotive, aerospace, and manufacturing. However, their design and control thus far has largely been based on “trial and error” methods requiring multiple trials and/or high levels of user specialization. Robust methods to realize flexible surfaces with the ability to deform into large curvatures therefore require a reliable, validated model that takes into account many physical and mechanical properties including elasticity, material characteristics, gravity, external forces, and thickness shear effects. The derivation of such a model would then enable the further development of predictive-based control methods for flexible robotic surfaces. This paper presents a lumped-mass model for flexible surfaces undergoing large deformation due to actuation by continuum robotic arms. The resulting model includes mechanical and physical properties for both the surface and actuation elements to predict deformation in multiple curvature directions and actuation configurations. The model is validated against an experimental system where measured displacements between the experimental and modeling results showed considerable agreement with a mean error magnitude of about 1% of the length of the surface at the final deformed shapes.

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“…7 On the other hand, ST essentially based on the characteristics of rigid body motion, can use only two coordinate frames, the base frame S and the tool frame T, to solve the kinematics and dynamics using a more concise expression which is a superior alternative to the Denavit–Hartenberg method in rigid-body robots. 8 ST has been applied to a wide variety of modelling and design problems including singularity analysis, kinematic synthesis methods and robot dynamics. Previous studies used different screw methods to model the kinematics and dynamics of robotic systems.…”

Section: Introductionmentioning

confidence: 99%

Rigid–flexible coupling dynamics with contact estimator for robot/PTL system

Zheng

Jiang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part K:

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In order to enhance sampling efficiency and security when robot maintains power transmission line (PTL), this article develops a new approach for the rigid-flexible coupling dynamics of robot/PTL system, which decouples the large system into two small systems and solves them separately by estimating the contact force. The robot is modelled as a system of rigid bodies by screw theory, while the PTL system is modelled using absolute node coordinate formulation (ANCF). The integration of screw theory, ANCF and contact estimator trained by artificial neural network has not been accomplished before in the literature. The main contribution of this paper is to achieve this integration with the goal of developing a new and general approach for the nonlinear dynamic analysis of the interaction of the rigid maintenance robot with flexible PTL cable. A simplified two-dimensional example is used to compute the effect of the robot/PTL interaction under different operating conditions to have an understanding of the coupling approach between the two systems. A more detailed three-dimensional model was developed, and the results obtained validate the utility and effectiveness of our approach.

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Kinematics and statics of eccentric soft bending actuators with external payloads

Cited by 44 publications

References 49 publications

Nonlinear energy-based control of soft continuum pneumatic manipulators

Nonlinear energy-based control of soft continuum pneumatic manipulators

A Lumped-Mass Model for Large Deformation Continuum Surfaces Actuated by Continuum Robotic Arms

Rigid–flexible coupling dynamics with contact estimator for robot/PTL system

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