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.

Design and Fabrication of Long SoftRobotic Elastomeric Actuator Inspired by Octopus Arm The biomimetic soft robotic actuators can provide stable flexible multipoint contact to safely grip delicate objects. A lot of soft robotic actuators have been fabricated using silica gel materials through molding methods. However, owing to the difficulty of the demolding process, existing soft robotic arms are often designed to be short. To fabricate a long soft robotic arm, this paper proposes a novel design approach for fabricating the long soft robotic arm (1000 mm) inspired by the octopus arm that is a fiberreinforced pneumatic elastomeric actuator. First, we develop a set of molds of the long soft robotic elastomeric actuator. To easily achieve the demolding of the soft actuator chamber, we design the three core petals around the mandrels in the molds. Furthermore, there are also two halfsegment mandrels. The two halfsegment mandrels are respectively removed from both ends of the mold when demolding. Then, we manufacture the long soft robotic arm using the molds by the combination silica gel and nonextensible materials. We also perform the experiments to verify the feasibility of the long soft robotic elastomeric actuator. The experimental results show the proposed design method for fabricating the long soft robotic arm is feasible.