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The purpose of this paper is to present the design of a microgripper system that comprises a dual jaw actuation mechanism with contact sensing.

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.

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.

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.

This paper aims to present design and characterization of a micrograsping system which is capable of safely grasping micro‐objects.

The proposed micrograsping system consists of novel MEMS based microgripper integrated with capacitive contact sensor (fabricated in standard micromachining process SOI‐MUMPs), sense electronics, a controller, high voltage actuation circuit and graphical user interface.

Due to the improvement in the lateral comb‐drive design, the actuator requires low actuation voltages in the range of 0‐45 V. This requires a simple and low power actuation circuitry. Capacitive feedback control mechanism is used in the sensor to detect the contact between the jaws and micro‐object while providing high values of the capacitance.

The designed sense electronics can sense the capacitance ranging from 0‐330 fF. Due to the availability of integrated contact sensor, objects ranging from 54 μm to 70 μm can be gripped safely with the applied maximum force of 220 μN at the tip of the gripper.

The performance of the microgripper, controller algorithm and associated electronics were experimentally quantified through the gripping of 65 μm sized human hair.

The purpose of this paper is to fabricate and investigate sensing properties of a novel, flexible resistive tensile load cells based on multi-walled carbon nano-tubes (MWCNTs)/rubber composites. The use of carbon nanotubes makes it very attractive for being used as sensors.

On thin rubber substrate, MWCNTs powder was deposited and pressed at elevated temperature. Two types of samples were prepared: first sample was made by depositing MWCNTs suspension in water on the substrate, then the sample was dried at room temperature; the second sample was prepared by applying dry MWCNTs powder directly on the substrate.

The resistances of the cells made from wet MWCNT powder are much lower than those made with dry powder. It was found that the fabricated load cells were highly sensitive to the force and showed good repeatability. The resistance of the flexible resistive tensile MWCNTs/rubber composite load cells increased 1.37 times, on average, with the increasing force (up to 0.045 N). The sensitivity of the cells was equal to 142 N-1.

The device fabrication method used here provides a simple, less expensive and effective approach for preparing resistive tensile load cells.

A novel, flexible resistive tensile load cells using MWCNTs/rubber composites have been successfully fabricated and investigated. MWCNTs, in dry and wet form, have been deposited on thin rubber substrates by adopting a very simple and inexpensive technique.