The necessity of the soft gripping devices is increasing day-by-day in medical robotics especially when safe, gentle motions and soft touch are necessary. In this paper, a novel asymmetric bellow flexible pneumatic actuator (AFPA) has been designed and fabricated to construct a miniaturised soft gripper that could be used to grip small objects. The model of AFPA is designed using solid works and its bending motion is simulated in Abaqus software for optimisation and compared with experimental results. The actuator is fabricated using compression molding process that includes micromachining of the molds. Experiments conducted show the bending characteristics of the actuator at different pressures. The actuator shows excellent bending performance and the eccentricity in its design supports increased bending or curling motion up to a certain extent compared to normal bellows without eccentricity. The effects of profile shape and eccentricity on the actuator performance are analysed and the results are presented. 1. Introduction Different types of soft actuators are developed that could generate the bending motion by themselves or by the mechanism that bends, due to their actuation [1, 2]. But most of these actuators are not single chamber or the actuator as a single cannot bend, but a combination of them with appropriate mechanism does the necessary bending motion [3–5]. Flexible pneumatic actuator (FPA) was designed by Joseph L. McKibben in the 1950s known as pneumatic muscle actuator. Toshiba Corp. (Japan) developed a three-degree-of-freedom actuator known as flexible microactuator (FMA) [6]. Even though the FMAs with two or more chambers with fiber reinforcement provide multiple DOF, they require multiple pressure supplies, valves, and sensors as well as complicated manufacturing. Asymmetric flexible pneumatic actuators (AFPAs) have been developed for the first time during the 1990s using asymmetric polymer/rubber tube and rubber bellow actuators with proper reinforcement to overcome the disadvantages of FMA and FPAs and proposed as an innovative method of fabricating a dexterous human hand [7, 8]. It has also been applied to fabricate a four fingered robot gripper [7–9] and microwalking robot [10]. The design and analysis for application to robotic hand using asymmetric nitrile rubber actuators have been studied [11–13]. Later symmetric thickness bellow actuators for miniature gripper fabricated by moulding technique and rubber bonding process with excimer light [14, 15] and asymmetric bellow actuator of about 10？mm diameter and 120？mm length that was
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