Adapting to Flexibility: Model Reference Adaptive Control of Soft Bending Actuators

Skorina, Erik H.; Luo, Ming; Tao, Weijia; Chen, Fu-Chen; Fu, Jie; Önal, Çağdaş D.

doi:10.1109/lra.2017.2655572

Cited by 54 publications

(41 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For the system (1) with the reference model (2), there exist 2 positive scalars γ 1 and γ 2 , a vectorθ t + , and a positive definite matrix P such that the following LMI is feasible: For the system (1) with the reference model (2), there exist 2 positive scalars γ 1 and γ 2 , a vectorθ t + , and a positive definite matrix P such that the following LMI is feasible:…”

Section: Figurementioning

confidence: 99%

“…For the plant (1) and the reference model (2), the MRAC consisting of (4) and (10) makes the whole signals of the closed-loop system bounded and the plant output y converges asymptotically to the output of the reference model y m .…”

Section: Theorem 1 (See the Work Of Ioannou And Sun 29 )mentioning

confidence: 99%

“…Theorem 2. For the system (1) with the reference model (2), there exist 2 positive scalars γ 1 and γ 2 , a vectorθ t + , and a positive definite matrix P such that the following LMI is feasible:…”

Section: Figurementioning

confidence: 99%

“…[1][2][3][4] Nevertheless, the improvement of its transient performance has long been a challenging problem. [1][2][3][4] Nevertheless, the improvement of its transient performance has long been a challenging problem.…”

Section: Introductionmentioning

confidence: 99%

“…Model reference adaptive control (MRAC) is an effective method in dealing with systems with uncertain parameters. [1][2][3][4] Nevertheless, the improvement of its transient performance has long been a challenging problem. This problem is especially complicated when parameter errors are large.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Transient performance improvement of model reference adaptive control: LMI‐based resetting

Davanipour

Khayatian

Dehghani

2017

Adaptive Control & Signal

View full text Add to dashboard Cite

In this paper, a resetting mechanism is proposed to enhance the transient performance of model reference adaptive control. While the suggested method has a simple structure, it is capable of taking into account both the desired steady-state behavior and the transient response, simultaneously. Whenever the transient specification is not satisfying, there is a jump in the controller parameters. This jump is determined by designing an optimal reset law. At the reset times, the after-reset values of parameters are calculated based on a minimization problem. The considered cost function is a mixed H 2 /H ∞ criterion, which minimizes the tracking error. The optimization problem is converted to an LMI formulation, and the reset law is designed by solving this LMI at certain reset times. To verify the effectiveness of the proposed approach, simulation results are presented. KEYWORDSlinear matrix inequality, model reference adaptive control, reset control, transient performance improvement 390 control acts as a disturbance that is in conflict with the control objective. There are also some research studies that use intelligent algorithms in MRAC to improve transient performance; however, they do not involve any analytical support for their statement. 16,17 There are also some research studies in robust adaptive control that propose some methods to improve transient performance. [18][19][20][21] In the work of Yucelen and Haddad, 18 an adaptive controller has been proposed in which the transient and steady-state bounds in terms of L 1 -norms of the error dynamic are obtained. In fact, the final bound of the system response can be determined independent of the system adaptation rate. In another work of Yucelen and Haddad, 19 to achieve fast adaptation, an adaptive control architecture with a high-gain learning rate has been presented. The controller includes an update law with a modification term that filters out the high-frequency content and makes the reduction of the high-frequency oscillations. Yucelen et al 20 proposed a new adaptive controller in which the reference system is modified by a mismatch term containing the high-frequency content of the closed-loop error dynamic. The suggested reference system causes the frequency content of the error dynamic to be restricted and allows fast adaptation without occurring high-frequency oscillations. In the work of Yucelen and Johnson, 21 a command governor-based adaptive controller that can achieve fast dominance of system uncertainties just by adjusting a given command was proposed.On the other hand, recently, a reset controller, which is a specific class of hybrid controllers, was introduced as a strong approach capable of overwhelming fundamental limitations of linear systems in transient performance. [22][23][24] The first reset controller named Clegg integrator was presented in 1958. 25 Clegg showed that, by using a reset mechanism in an integrator, it has the same magnitude as a pure integrator but with 38.1 • phase lag compared with the phase lag of a standard integra...

show abstract

Section: Figurementioning

confidence: 99%

Section: Theorem 1 (See the Work Of Ioannou And Sun 29 )mentioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Transient performance improvement of model reference adaptive control: LMI‐based resetting

Davanipour

Khayatian

Dehghani

2017

Adaptive Control & Signal

View full text Add to dashboard Cite

show abstract

Paper Robotics: Self‐Folding, Gripping, and Locomotion

Ryu

Mohammadifar

Tahernia

et al. 2020

Adv Materials Technologies

View full text Add to dashboard Cite

a century, sensational engineering efforts have been performed to develop new synthetic materials, and intensive studies of forces needed to deform those soft materials have examined the use of pneumatic, thermal, electrical, and chemical energy. [11][12][13] The second research stream designs low-profile, sheet-like robots, named "robotic origamis" (or "robogamis") that offer softness and reconfigurability with multiple bending degrees of freedom. [8][9][10] In robogamis, the rigid sheets are connected through soft joints, where 2D patterns can be folded into 3D structures by low profile actuations such as electrostatic forces, shape memory alloys, and pneumatic pressures. [2] Such robogamis can autonomously transform themselves into programmed shapes and perform complex tasks in unpredictable environments. Substantial progress in soft material research has produced achievements that are critical in terms of robogami techniques [2] while soft robotics and origami folding concepts have opened new applications. [9] However, soft robotics and robogamis have historically developed separately, and studies on robogamis with soft matter were unavailable or quite limited even though their integration is expected to generate substantial achievements in terms of cost, fabrication, operation, and performance. Built-in folds made of soft materials have the considerable potential to yield continuum, compliant, and configurable properties for robots.In this work, we introduce a new approach to combine these two robotic techniques by using soft paper substrates and a waterresponsive origami technique. The capillary action of sprayed water molecules is constrained by hydrophilic channels on paper, whose number and size are carefully defined by double-sided printing and the asymmetrical penetration of wax. In particular, a bilayered single sheet of paper that uses wax and water can lead to programmed deformations from different swelling and shrinking properties of the layers. A wax-water pattern on paper develops a folding actuation with a specific degree and shape and unfolding with evaporation without being mechanically manipulated by external forces or moments. The 2D sheet of paper can be controllably self-folded into various 3D structures, demonstrating self-folding actuation, low-weight object manipulation, and biomimetic locomotion through bending and relaxation. Although a couple of paper-based robotic concepts were partly proposed before, [14,15] no technique has yet emerged as a simple print-and-fold actuator powered by environmental humidity or water for comprehensive robotic functions including self-folding, Soft robotics driven by origami can fundamentally advance robotic functionalities by significantly improving continuum, compliance, and configurability. Here, a new field is proposed, "paper robotics," which is based on moistureresponsive self-folding of paper substrates into functional 3D machines using origami-inspired techniques. By properly designing a hydrophobic wax layer and a hygro-expandable hydrophilic ...

show abstract

Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments

Xavier

Fleming

Yong

2020

Advanced Intelligent Systems

186

View full text Add to dashboard Cite

Soft robotics has experienced an exponential growth in publications in the last two decades. [1] Unlike rigid conventional manipulators, [2,3] soft robots based on hydrogels, [4,5] electroactive polymers, [6,7] and elastomers [7-9] are physically resilient and can adapt to delicate objects and environments due to their conformal deformation. [10,11] They also show increased safety and dexterity can be lightweight and used within constrained environments with restricted access. [12,13] Many soft robots have a biologically inspired design coming from snakes, [14-17] worms, [18-20] fishes, [21-24] manta rays, [25,26] and tentacles. [27-29] The scope of applications includes minimally invasive surgery, [30,31] rehabilitation, [32,33] elderly assistance, [34] safe human-robot interaction, [35,36] and handling of fragile materials. [37,38] Important features of soft robotics design, fabrication, modeling, and control are covered in the soft robotics toolkit. [39,40] The building blocks of soft robots are the soft actuators. The most popular category of soft actuator is the soft fluidic actuator (SFA), where actuation is achieved using hydraulics or pneumatics. [8,41] These actuators are usually fabricated with silicone rubbers following a 3D molding process, [42] although directly 3D printing the soft actuators is also possible. [43,44] Silicone rubber is a highly flexible/extensible elastomer with high-temperature resistance, lowtemperature flexibility, and good biocompatibility. [45] Elastomers can withstand very large strains over 500% with no permanent deformation or fracture. [46] For relatively small strains, simple linear stress-strain relationships can be used, and two of the following parameters can be used to describe the elastic properties: bulk compressibility, shear modulus, tensile modulus (Young's modulus of elasticity), or Poisson's ratio. [45] For large deformations, nonlinear solid mechanic models using hyperelasticity should be considered. [8,32,47-50] Due to the strong nonlinearities in SFAs and their complex geometries, analytical modeling is challenging. [51] A brief review of the analytical methods for modeling of soft robotic structures is provided in the following. 1.1. Analytical Modeling of Soft Actuators The majority of soft/continuum robots with bending motion can be approximated as a series of mutually tangent constant curvature sections, i.e., piecewise constant curvature. [52] This is a result of the fact that the internal potential energy is uniformly distributed along each section for pressure-driven robots. [53] This approach has also been validated using Hamilton's principle by Gravagne et al. [54] As discussed by Webster and Jones, [52] the kinematics of continuum robots can be separated into robotspecific and robot-independent components in this approach. The robot specific mapping transforms the input pressures P or actuator space q to the configuration space κ, ϕ, l, and the robot-independent mapping goes from the configuration space to the task space x. The actuator space contai...

show abstract

Adapting to Flexibility: Model Reference Adaptive Control of Soft Bending Actuators

Cited by 54 publications

References 16 publications

Transient performance improvement of model reference adaptive control: LMI‐based resetting

Transient performance improvement of model reference adaptive control: LMI‐based resetting

Paper Robotics: Self‐Folding, Gripping, and Locomotion

Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments

Contact Info

Product

Resources

About