Linear and Nonlinear Low Level Control of a Soft Pneumatic Actuator

Ibrahim, Serhat; Krause, Jan Christoph; Raatz, Annika

doi:10.1109/robosoft.2019.8722737

Cited by 18 publications

(18 citation statements)

References 11 publications

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“…The pressure p end is measured at the end of the tube. The friction resistance is described in Ibrahim et al (2019) as…”

Section: Model Of Connecting Tubesmentioning

confidence: 99%

“…Introduced in Ibrahim et al (2019), the use of fast switching valves allows to neglect the spool dynamic Eq. 7.…”

Section: System Dynamicsmentioning

confidence: 99%

“…The valve model is based on the work of Ben-Dov and Salcudean (1995) and Richer and Hurmuzlu (2000a) , Richer and Hurmuzlu (2000b) . For a detailed description of the valve modeling, we refer to our preliminary work in Ibrahim et al (2019) . The air mass flow

through an orifice A of the valve is described with

…”

Section: Introductionmentioning

confidence: 99%

“…The pressure

is measured at the end of the tube. The friction resistance is described in Ibrahim et al (2019) as

with the model of Sutherland and its constant

and a substance-specific temperature S . By using short and wide tubes, the friction and time delay are minimal and can be neglected.…”

Section: Introductionmentioning

confidence: 99%

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Modeling and Reconstruction of State Variables for Low-Level Control of Soft Pneumatic Actuators

Ibrahim¹,

Krause²,

Olbrich³

et al. 2021

Front. Robot. AI

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To further advance closed-loop control for soft robotics, suitable sensor and modeling strategies have to be investigated. Although there are many flexible and soft sensors available, the integration into the actuator and the use in a control loop is still challenging. Therefore, a state-space model for closed-loop low-level control of a fiber-reinforced actuator using pressure and orientation measurement is investigated. To do so, the integration of an inertial measurement unit and geometric modeling of actuator is presented. The piecewise constant curvature approach is used to describe the actuator’s shape and deformation variables. For low-level control, the chamber’s lengths are reconstructed from bending angles with a geometrical model and the identified material characteristics. For parameter identification and model validation, data from a camera tracking system is analyzed. Then, a closed-loop control of pressure and chambers’ length of the actuator is investigated. It will be shown, that the reconstruction model is suitable for estimating the state variables of the actuator. In addition, the use of the inertial measurement unit will demonstrate a cost-effective and compact sensor for soft pneumatic actuators.

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“…The pressure p end is measured at the end of the tube. The friction resistance is described in Ibrahim et al (2019) as…”

Section: Model Of Connecting Tubesmentioning

confidence: 99%

“…Introduced in Ibrahim et al (2019), the use of fast switching valves allows to neglect the spool dynamic Eq. 7.…”

Section: System Dynamicsmentioning

confidence: 99%

through an orifice A of the valve is described with

…”

Section: Introductionmentioning

confidence: 99%

“…The pressure

is measured at the end of the tube. The friction resistance is described in Ibrahim et al (2019) as

with the model of Sutherland and its constant

and a substance-specific temperature S . By using short and wide tubes, the friction and time delay are minimal and can be neglected.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling and Reconstruction of State Variables for Low-Level Control of Soft Pneumatic Actuators

Ibrahim¹,

Krause²,

Olbrich³

et al. 2021

Front. Robot. AI

Self Cite

View full text Add to dashboard Cite

show abstract

“…Furthermore, these valves would still have a non-linear response. 27 Instead, our system uses inlet and outlet valves. In addition, we propose a proportional-integral-derivative (PID) position controller with gain scheduling to reduce the non-linear valve response behavior by considering the variance of valve flow rates secondary to differential pressures of various magnitudes.…”

Section: Introductionmentioning

confidence: 99%

A proposed soft pneumatic actuator control based on angle estimation from data-driven model

Mohamed¹,

Wagdy²,

Atalla

et al. 2020

Proc Inst Mech Eng H

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This article proposes a bending angle controller for soft pneumatic actuators, which could be implemented in soft robotic rehabilitation gloves to assist patients with hand impairment, such as stroke survivors. A data-driven model is used to estimate the angle as pneumatic pressure is applied to the actuator. Furthermore, a finite element model was used to manually optimize the dimensions of the actuator. An embedded flex sensor, which together with a custom testing rig, was used to gather input data for the data-driven model. This rig contains a pneumatic pressure control circuit as well as a camera for image acquisition. Collected data were fed into a linear regression model to predict the data-driven model. Experiments were carried out to validate model’s accuracy as well as modified proportional–integral–derivative controller angle controller performance. The latter controller is designed to mitigate the non-linear response of solenoid valves at different pressures of the actuator. The data-driven model along with the used controller allows more accurate estimation and quicker response.

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Design and Characterization of a 3D Printed Soft Pneumatic Actuator

Morales

Ibrahim

Cao

et al. 2020

Mechanisms and Machine Science

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In soft robotics, the successful development of soft robots involves careful designing that can benefit from current technologies. The use of Finite Element Method (FEM) software and additive manufacturing is essential to optimize the design before fabrication and to facilitate the process. Therefore, we present the design of a 3D printed low-pressure soft pneumatic actuator (SPA) with 3 DoF and a material characterization method to simulate the behaviour of the system. In attempt to define a suitable material modelling method and its reliability to simulate actuator behaviours, we introduce a characterization method and corroborate its efficiency through the evaluation of the performance using the FEM and preliminary tests of the actuator performance. The purpose of this article is to help future projects to effectively simulate the behaviour of 3D printed soft pneumatic actuators to improve the design before fabrication. Throughout the description of the process to effectively fabricate a functional SPA.

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Linear and Nonlinear Low Level Control of a Soft Pneumatic Actuator

Cited by 18 publications

References 11 publications

Modeling and Reconstruction of State Variables for Low-Level Control of Soft Pneumatic Actuators

Modeling and Reconstruction of State Variables for Low-Level Control of Soft Pneumatic Actuators

A proposed soft pneumatic actuator control based on angle estimation from data-driven model

Design and Characterization of a 3D Printed Soft Pneumatic Actuator

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