Soft Controllable Carbon Fibre-based Piezoresistive Self-Sensing Actuators

Abstract

Soft robots and devices exploit deformable materials that are capable of changes in shape to allow conformable physical contact for controlled manipulation. While the use of embedded sensors in soft actuation systems is gaining increasing interest, there are limited examples where the body of the actuator or robot is able to act as the sensing element. In addition, the conventional feedforward control method is widely used for the design of a controller, resulting in imprecise position control from a sensory input. In this work, we fabricate a soft self-sensing finger actuator using flexible carbon fibre-based piezoresistive composites to achieve an inherent sensing functionality and design a dual-closed-loop control system for precise actuator position control. The resistance change of the actuator body was used to monitor deformation and fed back to the motion controller. The experimental and simulated results demonstrated the effectiveness, robustness and good controllability of the soft finger actuator. Our work explores the emerging influence of inherently piezoresistive soft actuators to address the challenges of self-sensing, actuation and control, which can benefit the design of next-generation soft robots.

Materials for Smart Soft Actuator Systems

“…Pneumatic/hydraulic actuated elastomers. Adapted and modified with permission, copyright 2020, Actuators. Surface tension-based elastomers .…”

Soft pneumatic actuator from particle reinforced silicone rubber: Simulation and experiments

“…Compared to the hard robotics, the soft actuators have good compliance, low impedance, and ability to achieve complex motions with single control inputs 1–3 . To further improve the performance of soft actuators, it is necessary to expand the materials and methods of chemistry and materials science into applications in soft actuators 4–7 . Flexible polymer materials, like silicone rubber are often adopted in fabricating such soft actuators 8–11 .…”

“…[1][2][3] To further improve the performance of soft actuators, it is necessary to expand the materials and methods of chemistry and materials science into applications in soft actuators. [4][5][6][7] Flexible polymer materials, like silicone rubber are often adopted in fabricating such soft actuators. [8][9][10][11] Nevertheless, the limited commercial silicone rubbers cannot fully meet the requirements, such as those actuators require higher stiffness.…”

Tough Bioinspired Composites That Self-Report Damage

“…Such sensors allow for the early detection of damage and thus prevent catastrophic failure . Moreover, recent developments in the fields of additive manufacturing and soft robotics have led to the successful design and implementation of piezoresistive components in functional and wearable composite materials. − In spite of these developments, several challenges remain. The inclusion of sensing networks in composite materials negatively impacts mechanical properties, , and strain-monitoring fiber optic sensors with diameters larger than typical reinforcing elements may even act as stress-concentrating structural defects that cause premature failure .…”