Soft Fabric-Based Pneumatic Sensor for Bending Angles and Contact Force Detection

Cheng, Nicholas; Low, Jin Huat; Ang, Benjamin W. K.; Goh, Aaron J. Y.; Yeow, Chen-Hua

doi:10.1109/jsen.2018.2882796

Cited by 19 publications

(12 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Soft fluidic robotics work by transferring fluidic power (flow and pressure) from one place to another. This power can be used for actuation 1 , sensing 3 , and control 2,4 . Soft fluidic actuators (SFAs) consist of mechanically compliant chambers that can be deformed using fluidic power.…”

Section: Introductionmentioning

confidence: 99%

Direct 3D Printing of Soft Fluidic Actuators with Graded Porosity

Willemstein¹,

Kooij²,

Sadeghi³

2022

Preprint

View full text Add to dashboard Cite

New additive manufacturing methods are needed to realize more complex soft robots. One example is soft fluidic robotics, which exploits fluidic power and stiffness gradients. Porous structures are an interesting type for this approach, as they are flexible and allow for fluid transport. Within this work, the Infill-Foam (InFoam) is proposed to print structures with graded porosity by liquid rope coiling (LRC). By exploiting LRC, the InFoam method could exploit the repeatable coiling patterns to print structures. To this end, only the characterization of the relation between nozzle height and coil radius and the extruded length were necessary (at a fixed temperature). Then by adjusting the nozzle height and/or extrusion speed the porosity of the printed structure could be set. The InFoam method was demonstrated by printing porous structures using styrene-ethylene-butylene-styrene (SEBS) with porosities ranging from 46% to 89%. In compression tests, the cubes showed large changes in modulus (more than 200 times), density (-89% compared to bulk), and energy dissipation. The InFoam method combined coiling and normal plotting to realize a large range of porosity gradients. This grading was exploited to realize rectangular structures with varying deformation patterns, which included twisting, contraction, and bending. Furthermore, the InFoam method was shown to be capable of programming the behavior of bending actuators by varying the porosity. Both the output force and stroke showed correlations similar to those of the cubes. Thus, the InFoam method can fabricate and program the mechanical behavior of a soft fluidic (porous) actuator by grading porosity.

show abstract

Section: Introductionmentioning

confidence: 99%

Direct 3D Printing of Soft Fluidic Actuators with Graded Porosity

Willemstein¹,

Kooij²,

Sadeghi³

2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Therefore, sensors are necessary in controlling a soft gripper. At present, the types of sensors used on soft grippers include resistive sensors [ 28 , 31 , 32 , 33 ], capacitive sensors [ 34 , 35 ], flexible electronics [ 36 ], strain sensitive fabrics [ 37 ], magnetic sensors [ 38 , 39 ], and soft pneumatic sensors [ 40 , 41 ]. As previous studies described, most of the above sensors are directly attached to the surface of the finger or manufactured together.…”

Section: Introductionmentioning

confidence: 99%

Modeling of a Soft-Rigid Gripper Actuated by a Linear-Extension Soft Pneumatic Actuator

Cheng

Jia

et al. 2021

Sensors

View full text Add to dashboard Cite

Soft robot has been one significant study in recent decades and soft gripper is one of the popular research directions of soft robot. In a static gripping system, excessive gripping force and large deformation are the main reasons for damage of the object during the gripping process. For achieving low-damage gripping to the object in static gripping system, we proposed a soft-rigid gripper actuated by a linear-extension soft pneumatic actuator in this study. The characteristic of the gripper under a no loading state was measured. When the pressure was >70 kPa, there was an approximately linear relation between the pressure and extension length of the soft actuator. To achieve gripping force and fingertip displacement control of the gripper without sensors integrated on the finger, we presented a non-contact sensing method for gripping state estimation. To analyze the gripping force and fingertip displacement, the relationship between the pressure and extension length of the soft actuator in loading state was compared with the relationship under a no-loading state. The experimental results showed that the relative error between the analytical gripping force and the measured gripping force of the gripper was ≤2.1%. The relative error between analytical fingertip displacement and theoretical fingertip displacement of the gripper was ≤7.4%. Furthermore, the low damage gripping to fragile and soft objects in static and dynamic gripping tests showed good performance of the gripper. Overall, the results indicated the potential application of the gripper in pick-and-place operations.

show abstract

“…Another alternative approach is to develop soft wearable sensors. For example, Cheng et al [ 22 ] proposed a soft fabric-based pneumatic sensor to detect bending angles and contact force in human-robot interaction. The developed sensor system is aimed at addressing the sensing problem of soft actuators.…”

Section: Introductionmentioning

confidence: 99%

Differential Soft Sensor-Based Measurement of Interactive Force and Assistive Torque for a Robotic Hip Exoskeleton

Wang

Zhang

et al. 2021

Sensors

View full text Add to dashboard Cite

With the emerging of wearable robots, the safety and effectiveness of human-robot physical interaction have attracted extensive attention. Recent studies suggest that online measurement of the interaction force between the robot and the human body is essential to the aspects above in wearable exoskeletons. However, a large proportion of existing wearable exoskeletons monitor and sense the delivered force and torque through an indirect-measure method, in which the torque is estimated by the motor current. Direct force/torque measuring through low-cost and compact wearable sensors remains an open problem. This paper presents a compact soft sensor system for wearable gait assistance exoskeletons. The contact force is converted into a voltage signal by measuring the air pressure within a soft pneumatic chamber. The developed soft force sensor system was implemented on a robotic hip exoskeleton, and the real-time interaction force between the human thigh and the exoskeleton was measured through two differential soft chambers. The delivered torque of the hip exoskeleton was calculated based on a characterization model. Experimental results suggested that the sensor system achieved direct force measurement with an error of 10.3 ± 6.58%, and torque monitoring for a hip exoskeleton which provided an understanding for the importance of direct force/torque measurement for assistive performance. Compared with traditional rigid force sensors, the proposed system has several merits, as it is compact, low-cost, and has good adaptability to the human body due to the soft structure.

show abstract

Soft Fabric-Based Pneumatic Sensor for Bending Angles and Contact Force Detection

Cited by 19 publications

References 25 publications

Direct 3D Printing of Soft Fluidic Actuators with Graded Porosity

Direct 3D Printing of Soft Fluidic Actuators with Graded Porosity

Modeling of a Soft-Rigid Gripper Actuated by a Linear-Extension Soft Pneumatic Actuator

Differential Soft Sensor-Based Measurement of Interactive Force and Assistive Torque for a Robotic Hip Exoskeleton

Contact Info

Product

Resources

About