Development of a reliable microgripper system based on failure analysis.

Purpose – The purpose of this paper is to present the design of a microgripper system that comprises a dual jaw actuation mechanism with contact sensing. Design/methodology/approach – Interdigitated lateral comb-drive-based electrostatic actuator is used to move the gripper arms. Simultaneous contact sensing of the gripper jaws has been achieved through transverse comb-based capacitive sensor. The fabricated microgripper produces a displacement of 16 μm at gripper jaws for an applied actuation voltage of 45 V. Findings – It is observed that the microgripper fails to operate for the maximum performance limits (70 μm jaws displacement) and produces uncontrolled force at the tip of the jaws > 45 V. Originality/value – A novel behavioral model of the microgripper system is proposed using the fabricated dimensions of the system to carry out a detailed analysis to understand the cause of this failure. The failure analysis shows that the microgripper system failed to operate in its designed limits due to the presence of side instability in the designed combs structure. Our proposed failure model helps in redesigning the actuator to ensure its operation above 45 V so that the gripper jaw can be displaced to its maximum limit of 70 μm and also result in the increase of the controlled force from 250 to 303 μN at the microgripper jaws. [ABSTRACT FROM AUTHOR]