ABS T R A C T In recent years, soft pneumatic actuators with soft and flexible materials have been widely studied in the field of soft gripper and soft bionic robot. Up to present, the soft actuators studied usually have one motion manner such as extending, bending, twisting or rotation. In this paper, we propose a new type of multi-degree-of-freedom soft pneumatic actuator (MDoF SPA) that can extend or rotate in response to pressured air inputted in different chambers. A fabrication method was proposed. A mathematical model based on large deformation theory was presented to predict the elongation displacement and bending angle. Moreover, finite element analysis and experimental investigation were performed to verify the theoretical results. The output force during elongation and blocking force during bending were also tested. Finally, two MDoF SPAs were utilized to fabricate a crawling robot. The gait and hardware of crawling robot were shown. The average moving speed of linear motion, maximum bending angle were investigated as well. Experiments revealed the robot actuated by MDoF SPAs has a good comprehensive performance, which has great potential in search, detection, rescue and other operations in a narrow environment. This work can guide the design and application of MDoF SPAs in the future.

Flexible sensing tends to be widely exploited in the process of human–computer interactions of intelligent robots for its contact compliance and environmental adaptability. A novel flexible capacitive tactile sensor was proposed for multi-directional force sensing, which is based on carbon black/polydimethylsiloxane (PDMS) composite dielectric layer and upper and lower electrodes of carbon nanotubes/polydimethylsiloxane (CNTs/PDMS) composite layer. By changing the ratio of carbon black, the resolution of carbon black/PDMS composite layer increases at 4 wt%, and then decreases, which was explained according to the percolation theory of the conductive particles in the polymer matrix. Mathematical model of force and capacitance variance was established, which can be used to predict the value of the applied force. Then, the prototype with carbon black/PDMS composite dielectric layer was fabricated and characterized. SEM observation was conducted and a ratio was introduced in the composites material design. It was concluded that the resolution of carbon sensor can reach 0.1 N within 50 N in normal direction and 0.2 N in 0–10 N in tangential direction with good stability. Finally, the multi-directional force results were obtained. Compared with the individual directional force results, the output capacitance value of multi-directional force was lower, which indicated the amplitude decrease in capacity change in the normal and tangential direction. This might be caused by the deformation distribution in the normal and tangential direction under multi-directional force.

In order to assist patients with finger rehabilitation training and grasping objects, we propose a new type of soft rehabilitation gloves (SRGs), which has both flexion/extension and abduction/adduction movement function for every finger. This paper describes the structure design of the bending actuator and rotating actuator, the fabrication process of the soft actuator, and the implementation of the soft wearable gloves based on a fabric glove. FEM simulation analysis and experiments were conducted to characterize the mechanical behavior and performance of the soft glove in terms of the angle output and force output upon pressurization. To operate this soft wearable glove, we designed the hardware system for SRGs with a flexible strain sensor and force sensor in the loop and introduced a force/position hybrid PID control algorithm to regulate the pressure inputted. Experiment evaluation focused on rehabilitation training gestures; motions and the precise grasping assistance function were executed. The rotating actuator between each finger can supply abduction/adduction motion manner for patients, which will improve rehabilitation effect. The experimental results demonstrated that the developed SRGs have the potential to improve hand movement freedom and the range of grasping successfully.

为了解决传统刚性机械手在水果采摘方面交互性差和安全性低等问题,设计了一种软体采摘机械手及其控制系统.机械手由4个驱动手指和法兰盘组成,每个手指由硅胶材料注入3D打印的模具固化形成,具有结构简单、成本低、效率高以及交互性好等优点.在正压和负压驱动下,可实现向内、外两个方向弯曲,抓取过程中能够自动适应抓取物体的形状大小.利用ABAQUS有限元仿真对其弯曲特性进行仿真,分析各个结构参数对弯曲角度的影响,得出最优的结构参数,据此设计制造软体机械手样机.机械手控制系统主要包括电路系统和气路系统,电路系统采用Stm32单片机与Labview上位机软件通讯,控制气路中电磁阀和比例阀的工作状态,并实时显示充气压力;气路系统中的比例阀用于调节气压大小,真空发生器用于提供负压实现向外侧弯曲,并通过电磁阀切换气路的工作模式(正压/负压).试验表明,研制的软体采摘机械手工作范围为0～ 60 kPa,能够抓取的最大负载大约为5.8 N,可实现对苹果、西红柿等水果的无损稳定抓取.

软体仿生机器人通常由软体材料制作,与环境交互时,相比刚性机器人拥有更好的柔顺性和适应性.详细综述了软体仿生机器人在仿生结构、抓取和医疗康复等领域的应用;在研究软体仿生机器人的仿生原理与方法、材料与驱动、建模与控制的基础上,分析了软体仿生机器人的研究现状以及未来发展趋势,变刚度和柔性传感器集成是软体机器人未来的发展方向.

设计了软体机械手的单指结构,利用有限元软件分析软体手指弯曲性能.通过失蜡法进行手指制作,然后对软体手指进行弯曲试验和末端力试验研究,最后集成在Dobot机械臂末端.搭建了软体机械手性能测试试验平台.同时对不同形状和大小的水果进行抓取试验,结果表明该多指软体机械手可完成对不同水果的无损抓取,具有良好的实用价值.