College of Mechanical Engineering, Beihua University, Jilin 132021, China.
Rev Sci Instrum. 2024 Feb 1;95(2). doi: 10.1063/5.0186757.
This paper develops an antagonistic variable-stiffness pneumatic flexible joint in which two groups of artificial muscles are symmetrically distributed on both sides of the elastic thin plate. The elastic thin plate restricts the axial movement of the joint. Therefore, the joint can achieve single-dimensional and bidirectional bending by controlling the air pressure value of the pneumatic artificial muscle. Two variable stiffness elastic dampers are also symmetrically installed on both sides of the elastic thin plate, using a positive-pressure driving method to achieve real-time posture maintenance function of the joint based on particle-blockage, wedge structure, and antagonistic effect. The mathematical models for the bending angle and stiffness of flexible joints were established, and relevant experiments were conducted. When the air pressure of the pneumatic artificial muscle is 0.32 MPa, the joint bending angle reaches 62.7°. When the bending angle is 60° and the air pressure of the variable-stiffness elastic damper is 0.5 MPa, the stiffness in the bending direction of the flexible joint with the variable-stiffness elastic damper is 6.9 times that of the flexible joint without the variable-stiffness elastic damper, and the stiffness in the reverse bending direction is 10.3 times that of the flexible joint without the variable-stiffness elastic damper under the same conditions.
本文研制了一种对偶变刚度气动软体关节，该关节在弹性薄板两侧对称布置两组人工肌肉。弹性薄板限制关节的轴向运动，通过控制气动人工肌肉的气压值，使关节实现单自由度双向弯曲。同时在弹性薄板两侧对称安装两组变刚度弹性阻尼器，采用正压驱动方式，基于颗粒阻塞、楔块结构和拮抗作用，实现关节的实时位姿保持功能。建立了软体关节弯曲角度和刚度的数学模型，并进行了相关实验。当气动人工肌肉气压为 0.32 MPa 时，关节弯曲角度达到 62.7°。当弯曲角度为 60°，变刚度弹性阻尼器气压为 0.5 MPa 时，带有变刚度弹性阻尼器的软体关节在弯曲方向的刚度是没有变刚度弹性阻尼器的软体关节的 6.9 倍，在反向弯曲方向的刚度是没有变刚度弹性阻尼器的软体关节的 10.3 倍，在相同条件下。
