An effective methodology to solve inverse kinematics of electroactive polymer actuators modelled as active and soft robotic structures

Abstract

Electroactive polymers (EAPs) generate highly non-linear deflections when they are used as actuators, which are known as artificial muscles. Though several modelling methods have been proposed before to understand their mechanical, chemical, electrical behaviours or 'electro-chemo-mechanical' behaviour, estimating the whole shape deflection of the EAP actuators has not been studied yet. Therefore, we report on (i) an effective methodology to estimate these actuators' whole shape deflection by employing a soft robotic actuator/ manipulator approach and (ii) an angle optimization method, which we call AngleOPT, to accurately solve the EAP actuators' inverse kinematic problem. Laminated polypyrrole (PPy) EAP actuators are employed to validate the soft robotic kinematic model which has more degrees of freedom than its input. This follows that we have reduced a difficult problem to an easy-to solve inverse kinematic problem (easier to solve) of a hyperredundant soft robotic system. A parametric estimation model is also proposed to predict the tip coordinates of the actuators for a given voltage. The experimental and numerical results are presented to demonstrate the efficacy of the methodology for estimating the EAP actuators' highly non-linear bending behaviour from the inverse kinematic model. The proposed methodology can be extended to other type of smart structures with a similar topology. © 2013 Elsevier Ltd.

Robots Hiper-Redundantes: Clasificación, Estado del Arte y Problemática

“…Además, la aparición de estos robots ha impulsado el estudio y la aplicación de novedosos métodos de actuación, utilizando materiales que presentan la propiedad de cambiar su rigidez (Cheng, Lobovsky et al 2012). Entre ellos, destacan voice coils o motores de bobina de voz (Seok, Onal et al 2013, Nemitz, Mihaylov et al 2016, polímeros electroactivos (Mutlu, Alici et al 2013), aleaciones con memoria de forma o SMAs (Laschi and Cianchetti 2014), imanes permanentes (Marchese, Onal et al 2011), redes neumáticas (Mosadegh, Polygerinos et al 2014) o incluso mediante pequeñas explosiones controladas (Shepherd, Stokes et al 2013). Además del tentáculo de pulpo, se han utilizado otros modelos biomecánicos basados en rayas de mar (Suzumori, Endo et al 2007), gusanos (Jung, Koo et al 2007, Lin, Leisk et al 2011) y estrellas de mar (Shepherd, Ilievski et al 2011).…”

Three-Dimensional Kinematic Modeling of Helix-Forming Lamina-Emergent Soft Smart Actuators Based on Electroactive Polymers

“…Alternatively, bending type EAP actuators can be modeled by adapting a soft robotic approach, in other words, the actuator can be represented by a kinematically analogous curve (so-called backbone curve). Such modelling approach can be utilized for a single PPyEAP actuator [34,35] not only for planar actuation but also for the three dimensional displacement of the soft actuator in order to estimate its conformal shapes. As the soft robotic modelling approach uses a high number of degrees of freedom to determine the soft actuator's or manipulator's kinematic configurations, the dynamic behavior of the soft system becomes more sophisticated.…”

An Optimum Design Method of Pneu‐Net Actuators for Trajectory Matching Utilizing a Bending Model and GA

“…Soft actuators are widely fabricated by using compliant materials (e.g., polymers [1], elastomers [2], and hydrogels [3][4][5]) which result in a vast potential of soft actuators to handle fragile objects, resist mechanical insults (e.g., blunt impacts and compressive forces), and realise complex motions [6][7][8]. Pneumatically powered actuators aim to use new design strategies so that they can rapidly provide complex motions with simple inputs, thereby inspiring a new wave of research activities [9][10][11].…”