Design Considerations for 3D Printed, Soft, Multimaterial Resistive Sensors for Soft Robotics

Abstract

Sensor design for soft robots is a challenging problem because of the wide range of design parameters (e.g., geometry, material, actuation type, etc.) critical to their function. While conventional rigid sensors work effectively for soft robotics in specific situations, sensors that are directly integrated into the bodies of soft robots could help improve both their exteroceptive and interoceptive capabilities. To address this challenge, we designed sensors that can be co-fabricated with soft robot bodies using commercial 3D printers, without additional modification. We describe an approach to the design and fabrication of compliant, resistive soft sensors using a Connex3 Objet350 multimaterial printer and investigated an analytical comparison to sensors of similar geometries. The sensors consist of layers of commercial photopolymers with varying conductivities. We characterized the conductivity of TangoPlus, TangoBlackPlus, VeroClear, and Support705 materials under various conditions and demonstrate applications in which we can take advantage of these embedded sensors.

Soft Robotics: A Review of Recent Developments of Pneumatic Soft Actuators

“…Various soft robots with various actuation methods (a) Actuator with multi-material 3D printing [11]. (Open Access); (b) Soft linear actuator [12].…”

“…In turn, many soft robotics designs have been made using '2.5D' designs, limited primarily by 3D printed capabilities and model complexity, or use abstract approaches with the current software available [22][23][24]. Fabrication has also been an area of interest; however, thanks to rapid growth in digital design and fabrication tools, there are now many ways to develop soft robots with different material selections and as well as embedded needed electronics into channels of the material for system use [11,[25][26][27][28].…”

“…Existing solutions of the inverse-kinematics problem are neglecting the consideration of the pose of the end effector [9,29]. This limited computation creates difficulty in avoidance of autonomous obstacles and movement Various soft robots with various actuation methods (a) Actuator with multi-material 3D printing [11]. (Open Access); (b) Soft linear actuator [12].…”

“…Either change can be detected and utilized to locate the contact or estimate the curvature [78,110,140,141]. These sensors can be 3D printed with multi material printing [11,110], or by mixing carbon powder with silicone [140], or through the use of conductive hydrogels [141]. These sensors provide good consistency with a wide range of sensitivity and curvature constraints for different applications, as in Figure 21.…”

“…A soft robotic gripper is constructed and tested using a similar sensor technology and fabrication method by Shih et al [142]. 3D multi material prints can be leveraged to create embedded sensors within soft robotic actuators capable of holding many different objects (A-E), 3D perspective of the scatter plot (F) and 2D perspective of the scatter plot (G) [11]. Another similar project was completed in 2015 by Homberg et al [143] and again in 2019 by Truby et al [144] (Open Access).…”