Mustafa Emre Karagozler

Miniature Endoscopic Capsule Robot using Biomimetic Micro-Patterned Adhesives

This paper presents a stopping and a locomotion mechanism to be used with an endoscopic microcapsule robot. In the diagnosis of gastrointestinal diseases, microcapsules have been developed recently as alternatives to conventional endoscopy. However, they have less accuracy and functionality in diagnosis as they lack the ability to control their position. We propose mechanisms to be used with such microcapsules that would enable them to anchor and crawl in any position inside the small intestines. The stopping mechanism, actuated by coil type shape memory alloys, makes use of dry and wet elastomer (PDMS) micro-patterned adhesives inspired by beetles to attach to the intestinal tract. The locomotion mechanism, inspired by the locomotion principles of inch-worms, is a modular expansion of the stopping mechanism. Both the stopping and the crawling locomotion mechanisms have been built and successfully tested inside a flexible vinyl tube. Results showed stopping with high repeatability and 0.5 mm/sec locomotion speed. The stopping mechanism was also integrated to a tethered camera for testing

Electrostatic latching for inter-module adhesion, power transfer, and communication in modular robots

A simple and robust inter-module latch is possibly the most important component of a modular robotic system. This paper describes a latch based on electric fields and capacitive coupling. Our design provides not only significant adhesion forces, but can also be used for inter-module power transmission and communication. The key insight presented in this paper, and the factor that enables electrostatic adhesion to be effective at the macroscale, is the use of electric field attraction to generate frictional shear forces rather than electric field attraction alone. A second important insight is that a specific degree of flexibility in the electrodes is essential to maximize their mutual coupling and the resulting forces - electrodes which are too flexible or too rigid will perform less well. To evaluate the effectiveness of our latch we incorporate it into a cubic module 28 cm on a side. The result is a latch which requires almost zero static power and yet can hold 0.6 N/cm2 of latch area.

A new endoscopic microcapsule robot using beetle inspired microfibrillar adhesives

The diagnosis of gastrointestinal diseases within the small intestine has been greatly advanced with the introduction of the endoscopic microcapsule in recent years. In an effort to increase its reliability and expand its functionality, a mechanism for stopping and locomoting the capsule within the digestive tract is proposed in this paper. This mechanism, actuated by shape memory alloy wires, utilizes a synthetic microfibrillar adhesive similar to the attachment mechanisms employed by beetles. This fibrillar attachment mechanism is a combination of molecular adhesion caused by van der Waals forces and liquid adhesion caused by capillary forces. The molecular adhesion is enhanced by the presence of microfibers, and the liquid adhesion arises from a secretion from the beetles footpad. A synthetic version of the beetles footpad was fabricated from PDMS using a silicon mold. Another version was created from SU-8 using photolithography. Testing revealed decent adhesion with glass and prepared pig intestine in vitro both with a silicone oil to simulate the secretion and without it. A prototype robot with simple polymer adhesive pads for stopping successfully attached and detached inside a flexible vinyl tube. An inch worm locomotion mechanism is proposed and is in the preliminary stages of fabrication and testing

Electrostatic actuation and control of micro robots using a post-processed high-voltage SOI CMOS chip

In this paper we present an energy efficient control and power conversion circuit in a 1µm HV SOI CMOS for a sub-millimeter robot known as a catom. The circuit provides power delivery through capacitive coupling and generates an internal high voltage that is then used to charge electrostatic actuation electrodes that move the robot. The architecture is implemented in a low power digital design and a novel high voltage driver that minimizes static power consumption for charging high voltage actuation electrodes. High voltage operation is extended by removing inherent parasitic FET gates through the post-processing removal of the Si backside carrier substrate of the SOI die.

Stress-driven MEMS assembly + electrostatic forces = 1mm diameter robot

As the size of the modules in a self-reconfiguring modular robotic system shrinks and the number of modules increases, the flexibility of the system as a whole increases. In this paper, we describe the manufacturing methods and mechanisms for a 1 millimeter diameter module which can be manufactured en masse. The module is the first step towards realizing the basic unit of claytronics, a modular robotic system designed to scale to millions of units.

A Highly Integrated 60 GHz 6-Channel Transceiver With Antenna in Package for Smart Sensing and Short-Range Communications

This work presents a highly integrated 57-64 GHz 4-channel receiver 2-channel transmitter chip targeting short range sensing and large bandwidth communications. The chip is housed in an embedded wafer level ball grid array package. The package includes 6 integrated patch antennas realized with a metal redistribution layer. The receiver patch antennas have a combined antenna gain of ≈10 dBi while each transmitter antenna has a gain of ≈6 dBi. The chip features a wide tuning range integrated VCO with a measured phase noise lower than -80 dBc/Hz at 100 kHz offset. Each of the differential transmitter channels shows a measured output power of 2-5 dBm over the complete frequency range. In addition, one transmitter channel features a modulator that can be digitally programmed to operate in either radar or communication mode. Each of the receiver channels has a measured conversion gain of 19 dB, a single-side-band noise figure of less than 10 dB and an input referred 1 dB compression point of less than 10 dBm. With all channels turned on the chip consumes a current of 300 mA from a 3.3 V supply. The functionality of the chip is demonstrated for both sensing and short range wireless communications.

Analysis and Modeling of Capacitive Power Transfer in Microsystems

As externally powered microsystems become more common, designers need better tools to understand power delivery systems such as non-resonant capacitive coupling. In this paper we present the first general method which allows a designer to easily model power delivery through capacitive coupling. The method uses a power iteration technique which allows one to analyze systems when the time to charge the coupling capacitor is longer than a charge cycle, enabling us to analyze a greater range of systems than previously possible. In fact, we are able to model the entire system with an equivalent resistance. We show that our model accurately reproduces both static and dynamic characteristics of the exact solution and that this model is general, in that it is valid for capacitor charge times that are longer as well as shorter than a charge cycle. This model also reveals several regions of operation where different parameters (e.g., capacitance, frequency and series resistance) dominate, allowing the designer to quickly and intuitively understand the design space for capacitive power transfer.

Paper generators: harvesting energy from touching, rubbing and sliding

We present a new energy harvesting technology that generates electrical energy from a users interaction with paper-like materials. The energy harvesters are flexible, light, and inexpensive, and they utilize a users gestures such as tapping, touching, rubbing and sliding to generate electrical energy. The harvested energy is then used to actuate LEDs, e-paper displays and various other devices to create novel interactive applications, such as enhancing books and other printed media with interactivity.

Electric flora: an interactive energy harvesting installation

We demonstrate an interactive, human-powered energy harvesting system that converts a persons movement into light. The installation explores the interaction of bodies in space, movement, materials, and electrostatic energy.