Development and Experimental Analysis of a Soft Compliant Tactile Microsensor for Anthropomorphic Artificial Hand

This paper presents the development and preliminary experimental analysis of a soft compliant tactile microsensor (SCTM) with minimum thickness of 2 mm. A high shear sensitive triaxial force microsensor was embedded in a soft, compliant, flexible packaging. The performance of the whole system, including the SCTM, an electronic hardware and a processing algorithm, was evaluated by static calibration, maximum load tests, noise and dynamic tests, and by focusing on slippage experiments. A proper tradeoff between final robustness and sensitivity of the tactile device was identified. The experiments showed that the tactile sensor is sufficiently robust for application in artificial hands while sensitive enough for slip event detection. The sensor signals were elaborated with the cumulative summation algorithm and the results showed that the SCTM system could detect a slip event with a delay from a minimum of 24.5 ms to a maximum of 44 ms in the majority of experiments fulfilling the neurophysiological requirement.     

Transmission power requirements for novel ZigBee implants in the gastrointestinal tract

In this paper, a novel multinode wireless monitoring platform, based on ZigBee communication standard, is presented and tested in vivo. The transmission power levels needed to establish a reliable connection from the different gastrointestinal districts are reported and compared with safety levels from international guidelines. These findings can be useful to evaluate the effectiveness of a commercial and standardized approach to implantable and miniaturized monitoring of physiological parameters.     

An implantable telemetry platform system for in vivo monitoring of physiological parameters

This paper describes a microcontroller-based multichannel telemetry system, suitable for in vivo monitoring of physiological parameters. The device can digitalize and transmit up to three analog signals coming from different sensors. The telemetry transmission is obtained by using a carrier frequency of 433.92 MHz and an amplitude-shift keying modulation. The signal data rate is 13 kb/s per channel. The digital microcontroller provides good flexibility and interesting performance, such as the threshold monitoring, the transmission error detection, and a low power consumption, thanks to the implementation of a sleep mode. The small overall size (less than 1 cm3), the power density compatible with current regulations for the design of implantable devices, and the dedicated packaging make the system suitable for in vivo monitoring in humans. The design, fabrication, operation, packaging, and performance of the system are described in this paper. An in vivo pressure monitoring case study is described as well.     

A New Mechanism for Mesoscale Legged Locomotion in Compliant Tubular Environments

We present design and experimental performance results for a novel mechanism for robotic legged locomotion at the mesoscale (from hundreds of microns to tens of centimeters). The new mechanism is compact and strikes a balance between conflicting design objectives, exhibiting high foot forces and low power consumption. It enables a small robot to traverse a compliant, slippery, tubular environment, even while climbing against gravity. This mechanism is useful for many mesoscale locomotion tasks, including endoscopic capsule robot locomotion in the gastrointestinal tract. It has enabled fabrication of the first legged endoscopic capsule robot whose mechanical components match the dimensions of commercial pill cameras (11 mm diameter by 25 mm long). A novel slot-follower mechanism driven via lead screw enables the mechanical components of the capsule robot to be as small while simultaneously generating 0.63 N average propulsive force at each leg tip. In this paper, we describe kinematic and static analyses of the lead screw and slot-follower mechanisms, optimization of design parameters, and experimental design and tuning of a gait suitable for locomotion. A series of ex vivo experiments demonstrate capsule performance and ability to traverse the intestine in a manner suitable for inspection of the colon in a time period equivalent to standard colonoscopy.     

Wireless implantable electronic platform for chronic fluorescent-based biosensors

The development of a long-term wireless implantable biosensor based on fluorescence intensity measurement poses a number of technical challenges, ranging from biocompatibility to sensor stability over time. One of these challenges is the design of a power efficient and miniaturized electronics, enabling the biosensor to move from bench testing to long term validation, up to its final application in human beings. In this spirit, we present a wireless programmable electronic platform for implantable chronic monitoring of fluorescent-based autonomous biosensors. This system is able to achieve extremely low power operation with bidirectional telemetry, based on the IEEE802.15.4-2003 protocol, thus enabling over three-year battery lifetime and wireless networking of multiple sensors. During the performance of single fluorescent-based sensor measurements, the circuit drives a laser diode, for sensor excitation, and acquires the amplified signals from four different photodetectors. In vitro functionality was preliminarily tested for both glucose and calcium monitoring, simply by changing the analyte-binding protein of the biosensor. Electronics performance was assessed in terms of timing, power consumption, tissue exposure to electromagnetic fields, and in vivo wireless connectivity. The final goal of the presented platform is to be integrated in a complete system for blood glucose level monitoring that may be implanted for at least one year under the skin of diabetic patients. Results reported in this paper may be applied to a wide variety of biosensors based on fluorescence intensity measurement.     

Integration of a miniaturised triaxial force sensor in a minimally invasive surgical tool

This paper reports preliminary results on design and fabrication of a cutting tool with an integrated triaxial force sensor to be applied in fetal surgery procedures. The outer diameter of the proposed device is 7.4 mm, but a scaled down design can be easily achieved. Linearity and hysteresis tests have been performed for both normal and tangential loadings. A linear transformation relating the sensor output to the external applied force is introduced and discussed. The typical working range for the conceived instrument is around 0.3 N, while 20 N and 1 N are, respectively, maximum normal and tangential forces for which the device robustness has been assessed.