Angle Control of Antagonistic Pneumatic Driven and Inflatable Arm Joint The conventional robot arms applied in various fields are demanded to have high force output, high accuracy, high efficiency. But they are seldom applied in human life, because of large weight, rigidity, hazards to people caused by collisions. Therefore the soft robotic arm that is stretchable, light weight, softness without possible of hazards, and high precision control is suitable to deploy in human life. Thus the purpose of this research is to develop the soft robotic arm by using antagonistic pneumatic driven system. In order to realize this concept, the joint activation mechanism is the key component. This study focuses on the angle control of the joint. In this paper, the robot arm made by polyethylene is proposed. Air bags made of polyethylene inside the joint achieve antagonistic driven states. Helical tube made of polyethylene is adhered joint outside for realizing rigidity. It is characterized that control rigidity is realized by controlling the pressure in the helical tube and joint angle is preciously controlled in two degree of freedom by controlling pressure in the air bags. Furthermore, the joint angle can be controlled by controlling the air pressures in the air bags using stretch sensor measuring joint angle. The experimental result confirmed that the driving concept of the joint was well functioned, and the joint angle control was realized by feedback control.

Soft Pneumatic Helical Actuator with High Contraction Ratio Soft contraction actuator has always been an important research field in soft robotics. This paper presents a novel soft contraction actuator which can realize highratio contraction when pressurized by pneumatic power. This actuator can be easily made by soft materials including rubber tube, oneway extensible cloth, inextensible cloth and wire. 2 types of structures are presented based on different working circumstances. When pressurized, the actuator can curve and then coil to a helical shape due to the different extensibilities of its opposite sides, a high contraction length and large contraction force can be achieved synchronously. Experiments are conducted to show the relationship between contraction force and contraction ratio of this actuator. The high contraction ratio of this actuator is revealed by comparing with McKibben actuator under the same condition, the maximal contraction ratio reaches 78% and the actuation stress is 8.36kPa.