Design and Control of a Biomimetic Octopus Wrist Flexible Arm

Introduction: Biomimetic flexible arms, with their outstanding flexibility, excellent environmental adaptability, and high flexibility, have shown broad application prospects in fields such as healthcare, detection, robotics, and human-computer interaction. Especially in minimally invasive surgery, disaster rescue, and complex environments, biomimetic flexible arms, as a new and efficient tool, have enormous market potential. This study takes the brachiopod octopus as a biomimetic blueprint and designs a control system for a biomimetic flexible arm based on control requirements. Methods: Based on the study of its mechanical structure and biological characteristics, a biomimetic flexible robotic arm driven by shape memory alloy (SMA) wires has been developed. We also proposed an SMA actuator linkage vector control method to achieve bending of flexible robot arms in any direction and angle. Results: We have successfully developed a biomimetic flexible arm prototype and built an experimental platform to test the motion and control performance of the flexible robotic arm. Discussion: The results of this study provide new ideas for the application of flexible robots in medical, rescue, and complex environments. Compared with traditional rigid robots, the design of biomimetic flexible arms not only improves the adaptability and flexibility of robots but also provides possibilities for their operation in narrow spaces. This innovation can significantly improve the operational accuracy of robots in minimally invasive surgery and other fields, thereby enhancing patient safety and surgical outcomes. Meanwhile, due to the fact that the experimental prototype in this study was handmade, there were significant differences in the prestress of the three groups of SMA wires during the installation process, which affected the control effect. And when we designed the SMA actuator linkage vector control strategy, multiple idealized assumptions were made, but these assumptions are difficult to fully implement in practical operation, resulting in deviations between experimental results and expectations. Conclusion: The maximum bending angle of the flexible robotic arm that we designed is 24 degrees. The variation law of the bending angle of the robot arm with voltage and time was obtained through experiments, and the experimental results were in good agreement with the theoretical analysis. The related achievements have been patented.