Design and Development of a Robotic Hand with Embedded Sensors Using 3D Printing Technology

摘要

This work presents the development of a robotic hand using 3D printing technology for robotic and prosthetic applications. The 3D printed hand presented herein is very cost-effective and involves elementary fabrication steps paving the way for rapid manufacturing at low cost. Fused deposition modeling (FDM) printers using polymer composites are used to print with optimized manufacturing settings to achieve a truly low-cost solution through minimal waste, minimal material requirement while achieving the required durability. Further, the 3D printed hand is embedded with pressure and strain sensors for tactile feedback required for human-like dexterity. A piezoresistive polymer-based flexible pressure sensor and an in-house carbon-coated elastic thread-based strain sensor are employed to realize the cost-effective 3D printed hand with tactile feedback. The sensors employed need a highly linear readout circuit for the effective implementation of the tactile feedback. Owing to this, a highly linear null detection-based Wheatstone bridge is proposed for the readout. Detailed analysis and their effect on the readout’s linearity are presented for the non-idealities involved in the design. A prototype is fabricated and tested to evaluate the performance of the circuit. Experimental results show that the circuit was able to reduce the nonlinearity error from 52% (in case of single-element Wheatstone bridge followed by a difference amplifier) to 0.14% for a wide resistance range from 1 kΩ to 1 MΩ. The circuit was further used as an analog readout for the sensors embedded in the 3D printed robotic hand. The complete system was finally evaluated under laboratory conditions verifying the design of the truly cost-effective and simple 3D printed robotic hand with tactile feedback.