Pseudo rigid body model for a nonlinear folding compliant mechanism

Hargrove, Brianne; Nastevska, Angela; Frecker, Mary; Jovanova, Jovana

doi:10.1016/j.mechmachtheory.2022.105017

Cited by 9 publications

(5 citation statements)

References 39 publications

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“…In this study, we apply the PRBM analytical modeling based on [37] to obtain the transfer function relationship between the pressure input and angular position of the soft actuator. PRBM is commonly used to analyze compliant mechanisms with linear elastic behavior [42]. Corollary, our model assumes a linear relationship between the pressure input and the soft actuator's behavior.…”

Section: Derivation Of Dynamic Equation Through Pseudo-rigid Body Mod...mentioning

confidence: 99%

Toward precise force control of soft hand grasping: The viscoelastic parameter estimation of pseudo-soft-rigid-model by applying logarithmic decrement method

Zhang,

Heung,

Deshpande

et al. 2024

Preprint

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The rapid advancement in physical human-robot interaction (HRI) has propelled the growth of soft robot design and, in parallel, soft robot controllers. Controlling soft robots is complex due to their wide range of movements, prompting the use of simplified model-based controllers to provide sufficient information for real-time high dynamic response control performance. However, most modeling techniques face computational efficiency and complexity of parameter identification issues and are hard to apply to real-time controls. To alleviate this, we employ a coupled analytical modeling approach based on Pseudo-Rigid Body Modeling and the Logarithmic Decrement Method for parameter estimation (PRBM+LDM). Using a soft robot hand test bed, we demonstrate the accuracy of PRBM+LDM to model position and force output as a function of pressure input and benchmark its performance. We, then, apply the PRBM+LDM model as a basis for a closed-loop position controller and compare its performance against a simple PID controller. Furthermore, we apply the PRBM+LDM model as a closed-loop force controller and compare its performance with simple constant pressure grasping control by performing small contact areas pinching tasks on low-weight, small objects - a screwdriver, a potato chip, and a brass coin. The PRBM+LDM-based position controller (Average Max. Error across all fingers: 4.37°) outperformed the simple PID position controller (Average Max. Error across all fingers: 20.38°). Furthermore, the PRBM+LDM-based force controller (Potato chip: 86%, Screwdriver: 74.42%, Brass coin: 64.75%) achieved a higher success rate than the constant pressure grasping control (Potato chip: 82.5%, Screwdriver: 70%, Brass coin: 35%) in the pinching tasks. We conclude that the PRBM+LDM modeling technique proves to be a convenient and efficient way to model the dynamic behavior of soft actuators closely and can be used to build high-precision position and force controllers. In application, it realizes stable, flexible grasping of small objects by exerting precise contact force on contact areas.

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Section: Derivation Of Dynamic Equation Through Pseudo-rigid Body Mod...mentioning

confidence: 99%

Toward precise force control of soft hand grasping: The viscoelastic parameter estimation of pseudo-soft-rigid-model by applying logarithmic decrement method

Zhang,

Heung,

Deshpande

et al. 2024

Preprint

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“…As to the kinematic and static analysis of compliant mechanisms, many theoretical methods are now available such as the PRBM, the matrix method, the elastic beam theory and Castigliano's second theorem [2,3].…”

Section: Pseudo-rigid-body Modelmentioning

confidence: 99%

“…The analysis is based on using Pseudo-Rigid-Body Model (PRBM) [3]. The PRBM is modeled using MATLAB and integrated with ISIGHT software to get the influence of input parameters on the output variable with different methods of design of experiments.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity Analysis of XY- Precision Positioning Compliant Mechanism

Said

Awad²,

Hedaya³

et al. 2022

Port-Said Engineering Research Journal

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Compliant mechanism becomes a promising alternative to the traditional ones for precision applications. Flexure hinge compliant mechanisms have been used in different fields. However, the design of their geometric parameters is so critical. Therefore, a lot of work are done in optimization of their design parameters. One of the main important steps is to select the sensitive parameters in such design problems. In this article a study of sensitivity of geometric parameters of positioning stage compliant mechanism are represented to be used as a pilot step for the selection of the optimization design variables. The effect of each parameter is regarding to the achieved amplification ratio of the positioning stage and the input stiffness of the mechanism. The modeling is done using Pseudo-Rigid-Body Model on MATLAB. The sensitivity analysis is done using ISIGTH software. The results of different sensitivity analysis methods reveal the most important parameters of the compliant mechanism that have significant effect on amplification ratio.

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“…Building on these advances, a contact-aided leaf hinge [24] with continuous variable stiffness was proposed. In addition, Hargrove et al [25] presented a nonlinear folding CCM and developed a segmented pseudo rigid body model that captures the geometric and material nonlinearity. Four issues can be identified among those existing designs as follows:…”

Section: Introductionmentioning

confidence: 99%

Design and analysis of a contact-aided flexure hinge (CAFH) with variable stiffness

Dai,

Hao,

Qiu

2024

Smart Mater. Struct.

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This paper presents a novel contact-aided flexure hinge (CAFH) with variable stiffness, which consists of a contact-aided segment, a flexible segment and a rigid part. The proposed CAFH can facilitate a compact design and provide an alternative for stiffness-variable designs under any loading conditions. With a mortise-tenon structure, the CAFH is trivially affected by friction. The design and deformation procedures of the CAFH are described in detail, followed by its theoretical kinetostatic modeling using the chained beam-constraint model (CBCM). The deformation of all segments is considered in the kinetostatic model, which expands the space of design parameters for stiffness-variable designs. Then, the accuracy of the theoretical model and the variable stiffness design are verified by nonlinear finite element analysis (FEA) and experimental tests. In term of stiffness, the maximum relative errors of the theoretical model are 0.76% in Stage 1 and 0.70 % in Stage 2, as compared with FEA, respectively. Further, the parameter sweep is carried out, followed by sensitivity analysis to identify the main test error sources. Finally, the multi-material scenarios are investigated preliminarily, and some outlooks are discussed.

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Pseudo rigid body model for a nonlinear folding compliant mechanism

Cited by 9 publications

References 39 publications

Toward precise force control of soft hand grasping: The viscoelastic parameter estimation of pseudo-soft-rigid-model by applying logarithmic decrement method

Toward precise force control of soft hand grasping: The viscoelastic parameter estimation of pseudo-soft-rigid-model by applying logarithmic decrement method

Sensitivity Analysis of XY- Precision Positioning Compliant Mechanism

Design and analysis of a contact-aided flexure hinge (CAFH) with variable stiffness

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