关节式内骨骼气动软体驱动器的结构设计  

Structure design of pneumatic soft actuator with jointed endoskeleton

作　　者：武兆平 李小宁[1] 郭钟华[1] Wu Zhaoping;Li Xiaoning;Guo Zhonghua(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学机械工程学院

出　　处：《农业工程学报》2019年第15期17-24,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金(51305202);江苏省自然科学基金(BK20130764)

摘　　要：软体驱动器具有优异的柔顺性,能适应不同形状的目标物体,且不易损伤被抓持物。为了在工业流水线上快速安全可靠地抓持诸如水果、精密元器件等不同质量、不同尺寸物体,该文介绍了一种新型关节式内骨骼气动软体驱动器,将驱动与承力功能分解,在保持柔顺性的同时,显著提高了抓持能力。推导了气压驱动下,驱动器的弯曲角度数学模型。以理论模型为基础,分析了驱动器的各项设计参数对弯曲角度的影响。以确定气压下自由端位姿作为输入条件,以驱动器整体质量最小为优化目标,优化了各参数值,并以得到的参数完成了软体驱动器的实物制造与装配,且试验获得了其弯曲角度与弯曲刚度。试验表明在最大工作压力为150 kPa时,总体误差控制在9%以内,证实了所建立驱动器理论模型的正确与有效性。驱动器的弯曲刚度在最大工作压力时达到4.50 N/rad,弯曲刚度得到大幅提高。该软体驱动器具有良好的开发和应用前景。Soft actuators are suitable for gripping fragile and delicate objects with irregular shapes and sizes owing to their high flexibility and have become a current research focus.But current soft actuators have a general problem of insufficient gripping force.To grip objects with different mass and sizes on assembly line safely and reliably,a novel pneumatic soft actuator with jointed endoskeleton structure was developed which separated the actuation and force bearing function.The bending action of the actuator was performed by the soft rubber with embedded radial-restrained fiber through pneumatic actuating,while the gripping force was bore and transferred by means of the jointed endoskeleton.To obtain the pose of free-end of the soft actuator,the theoretical model was built up.Firstly,the strain energy function of silicon rubber(Yeoh model)was used for deducing the stress and strain.Secondly,the relation between bending angle and input pressure was analyzed.Then the pot matrix of the free-end could be acquired through D-H method.Moreover,to determine the size parameters to facilitate the prototype,the sectional radius,the sectional height,the axial length and the wall thickness were chosen as the design parameters to analyze.The influences for bending of the actuator were discussed.The results showed that the input pressure reduced along with the increase of the sectional radius and the axial length while increased with the increase of the sectional height and the wall thickness.Furthermore,an optimization design algorithm was developed based on the theoretical model.At first,the strain-stress curve of the silicon rubber was measured by tensile test and the coefficients of Yeoh model were obtained.The determined pressure and the expected pose of the free-end were defined as the input while the minimum weight was the optimization target.Then 4 key design parameters could be calculated by the algorithm.With the obtained design parameters,the soft actuator was fabricated and relevant experiments were conducted.An expe

关 键 词：设计 优化 软体驱动器 气动 内骨骼 刚度 柔顺性 

分 类 号：TH138[机械工程—机械制造及自动化]