刚度增强型气动软体驱动器优化设计与试验

Optimization Design and Experiment of Pneumatic Soft Actuator with Stiffness Enhancement

针对软体机器人刚度不足的问题,设计了一种内置弹性骨架的刚度增强型气动软体驱动器。基于二参数Yeoh模型建立驱动器材料本构模型,通过拉伸试验获得材料参数。利用有限元分析软件优化驱动器设计,分别对气囊结构、几何参数,纤维线径、缠绕角,弹性骨架刚度等进行仿真分析,获得设计参数对驱动器弯曲角度和刚度的影响规律。由仿真结果可知:具有扇形截面气腔、较大长径比、较薄外壁厚、较大腔室角及较细纤维线径的驱动器能提供更高柔性,而内置的弹簧骨架能够在保证柔性的同时提升刚度。根据优化设计结论,制作驱动器样机并进行试验验证。结果表明:设计的软体驱动器动作灵活柔顺,在0.16 MPa气压下弯曲角度可达55°,增设适宜骨架后,刚度提升了65.4%。

A stiffness-enhanced pneumatic soft actuator with built-in elastic skeleton to address the under-rigidity of soft robots was designed.Based on the two-parameter Yeoh model,a constitutive model of the actuator material was developed and material parameters were obtained by tensile experiments.The design of the actuator was optimized by using finite element analysis software.The air chamber structure and geometrical parameters,fiber diameter and winding angle,and elastic skeleton stiffness were simulated and analyzed separately.The influence of the design parameters on the bending angle and stiffness of the actuator was obtained.Simulation results indicate that actuators equipped with fan-shaped cross-sectional air chambers,increased length-to-diameter ratio,thinner outer wall thickness,larger chamber angles,and finer wire diameters are capable of providing higher degree of flexibility.Additionally,the inclusion of built-in spring structures can ensure flexibility while simultaneously improving stiffness.Based on the conclusions of optimized design,the actuator prototype was fabricated and experimentally validated.The experimental results show that the designed soft actuator exhibits flexibility and compliance,with the ability to achieve a bending angle of 55°under air pressure of 0.16 MPa.Moreover,the inclusion of suitable skeleton increased the stiffness by 65.4%.