Movement Detection in Soft Robotic Gripper Using Sinusoidally Embedded Fiber Optic Sensor

Abstract

Soft robotics is an emerging field, since it offers distinct opportunities in areas where conventional rigid robots are not a feasible solution. However, due to the complex motions of soft robots and the stretchable nature of soft building materials, conventional electronic and fiber optic sensors cannot be used in soft robots, thus, hindering the soft robots’ ability to sense and respond to their surroundings. Fiber Bragg grating (FBG)-based sensors are very popular among various fiber optic sensors, but their stiff nature makes it challenging to be used in soft robotics. In this study, a soft robotic gripper with a sinusoidally embedded stretchable FBG-based fiber optic sensor is demonstrated. Unlike a straight FBG embedding configuration, this unique sinusoidal configuration prevents sensor dislocation, supports stretchability and improves sensitivity by seven times when compared to a straight configuration. Furthermore, the sinusoidally embedded FBG facilitates the detection of various movements and events occurring at the soft robotic gripper, such as (de)actuation, object holding and external perturbation. The combination of a soft robot and stretchable fiber optic sensor is a novel approach to enable a soft robot to sense and response to its surroundings, as well as to provide its operation status to the controller.

Speckle-based high-resolution multimodal soft sensing

“…In the past decades, significant progress has been made to develop sensing capabilities with high sensitivity, high resolution, and fast response in flexible and stretchable substrates with a large area 27 . Different sensing mechanisms have been proposed and demonstrated, including electrical signal transduction strategies such as resistive 8 , capacitive 1 , piezoelectric 2 , and triboelectric 3 methods, or detection strategies based on optical waveguide structures, such as stretchable waveguides 16 , optical fibers 17 – 19 , and fiber Bragg gratings 28 , 29 . Although these sensing mechanisms can play a crucial role in detecting different types of physical stimuli, most of the currently available sensors focus on detecting only a single physical stimulus and cannot distinguish between multiple stimuli simultaneously.…”

Airflow vibration of diaphragmatic breathing: model and demonstration using optical biosensor

“…The principle of strain in FOS usually uses a bending method with various patterns such as circular [17], straight [18], and sinusoidal [19]. However, sinusoidal patterns proved to be more effective than other forms in detecting changes in sensor parameters in the human body [20]. Therefore, the FOS technology developed in this study uses a sinusoidal configuration of SMF and FBG arranged in an elastic belt which is then attached to the diaphragm.…”

Optical skin: Sensor-integration-free multimodal flexible sensing

“…In the past decades, significant progress has been made to develop sensing capabilities with high sensitivity, high resolution, and fast response in flexible and stretchable substrates with a large area [27]. Different sensing mechanisms have been proposed and demonstrated, including electrical signal transduction strategies such as resistive [8], capacitance [1], piezoelectric [2], and triboelectric [3] methods, or a detection strategy based on optical waveguide structures, such as stretchable waveguides [16], optical fibers [17][18][19], and fiber Bragg gratings [28,29]. Although these sensing mechanisms can play a crucial role in detecting different types of physical stimuli, most currently available sensors focus on detecting only a single physical stimulus and cannot distinguish between multiple stimuli simultaneously.…”