Prosthetics, exoskeletons, and rehabilitation devices that seamlessly respond to the user's motion intent are essential for improving the quality of life for individuals with physical disabilities. However, existing motion intent recognition systems based on Electromyography (EMG) often experience significant performance degradation over time and limb positions. To address this, this paper proposed a Hierarchical EMG-FMG Fusion (HEFF) framework that incorporates Force Myography (FMG) as a complementary modality to enhance robustness in long-term and multi-position motion intent recognition. The HEFF framework introduced three new strategies: (1) Complementary Pyramid Fusion, a neural network architecture that effectively integrates the complementary characteristics of EMG and FMG; (2) Position Compensation and Pairing, to increase the generalizability of the model by producing augmented training data mimicking the temporal and positional variability; and (3) Feedback-based Baseline Correction, to dynamically counteract FMG baseline drift. The robustness of the system was evaluated through 10 distinct motions performed in 3 different limb positions, retested after an interval of approximately 7 days. Notably, the training data were only collected in a single limb position on the first day. The real-time experiments with 15 subjects showed that the HEFF framework maintained 91.89% classification accuracy in the primary limb position and 85.39% across multiple unseen positions. According to offline analysis, HEFF improved classification accuracy by up to 34.99% across various limb positions compared to the conventional fusion method. These results highlight HEFF's robustness across various conditions, being well-suited for assistive technology applications.

This article reports an automated optically-induced dielectrophoresis (ODEP) system for characterizing the specific membrane capacitance (SMC) of individual cells. The simulation of cell motion is conducted to analyze the electrokinetic forces acting on the cell. A self-developed visual tracking algorithm for multicells is used to realize an automated process for determining the frequency-sweeping range, crossover frequencies, and cell radii. The SMC values of malignant bladder cancer cells (T24 and RT4) and normal urothelial cells (SV-HUC-1) were quantified using the automated system, demonstrating that the system has a measurement speed of ~1 cell/s, an accuracy of 1 kHz for the crossover frequency determination, and an accuracy of 0.2 μm for the cell radius measurement.

We present in this paper a novel indoor blimp that is propelled by a propulsion technology that uses no moving mechanical parts and thus is noiseless and vibration free. In our prior work reported at IEEE/ASME AIM 2007, we demonstrated several prototype propulsive units (with asymmetric capacitor configurations) that lift themselves into air. Using these basic propulsive units (“Ionic Flyers”), we have recently developed an indoor flying blimp that has a propulsion system with no moving mechanical parts and thus generates no noise or vibration - the Ionic Propulsion Blimp. The key to successfully create this novel indoor flying system is the development of a power generation system that includes an 11.1V battery which is capable of generating ∼20kV DC voltage continuously over time for a load in the MΩ range. The architecture of this ionic power system will be presented. A detailed parametric analysis and an optimal design methodology of the Ionic Flyer are also discussed. Initial experimental results of the Ionic Propulsion Blimp are also summarized in this paper.

This paper aims at developing a force-guided micromanipulation technology with in-situ PVDF beam force sensing and hybrid force/position control based on an infinite dimensional system model. By using the designed PVDF force sensing cantilever composite structure with high sensitivity, the micro contact force/impact signal and its derivative can be extracted and processed. As the sensor structure installed at the end of micromanipulator is a soft beam, when manipulation is performed, the cantilever beam is necessary to be considered as a distributed parameter flexible link, then we developed a hybrid micro contact force/position control scheme on the basis of an infinite dimension system model. Experimental results verify the performance of the developed micro force sensing and hybrid control scheme. Ultimately the technology will provide a critical and major step towards the development of automated manufacturing processes for batch assembly of micro devices.

A novel system for 3D microchannel fabrication based on CO/sub 2/ laser-micromachining is presented. The system consists of a CO/sub 2/ laser focusing system and a 3D precision positioning platform. The CO/sub 2/ laser focusing system can regulate a laser beam which is of appropriate energy level and of micron dimension in beam diameter. The fabrication of 3D microchannel system in PMMA (polymethyl methacrylate) can be realized by controlling the CO/sub 2/ laser and a 3-axis platform with micron-resolution movement. A special 'sacrificial mask' process was used to produce translucent channels of micron dimensions with low surface roughness using the developed system. The effectiveness of our developed system is confirmed by experimental results. Potentially, our developed system can be automated to produce 3D micro channels in PMMA substrates without the requirement for the costly and time-consuming lithography and hot-embossing processes that are needed currently.

A polymer based vortex micropump fabricated by micro molding replication technique is described in this paper. The optically transparent and biocompatible material used to fabricate the micropump will enable the pump to be applied on many biomedical and chemical analyses applications. Fluid transmission of the vortex micropump is driven by the circumrotating motion of an impeller inside the micropump. The pump rate can reach 2.5 ml/min at a low operating voltage of 3 V with a power consumption of 345 m W from the experimental results. The fabrication process and performance characterization of this novel micropump is described in this paper.

DNA electronics circuits require an efficient way to accurately position and individually manipulate DNA molecules. The recent development of atomic force microscopy (AFM) seems to be a promising solution. We have recently developed an AFM based augmented reality system. This new system can provide both real-time force feedback and real-time visual feedback during nanomanipulation. We have shown that nano-imprinting and manipulation of nano-particles and nano-rods can be easily performed under assistance of the augmented reality system. In this research, the system's ability is extended to manipulation of DNA molecules. Using a polynomial fitting method, the deformation of DNA molecules is displayed in real time in the augmented reality system during manipulation. Indeed, DNA molecules adopt many different structures including kinks, bends, bulges and distortions. These different structures and inappropriate physical contacts may result in the controversy of DNA conductivity reported over the last decade. The AFM based nanomanipulation system can be used either as a nanolithography tool to make small gap electrodes or a nanomanipulation tool to elongate, deform and cut DNA molecules. The measurement of the conductivity of DNA molecules in their different shapes and structures is a promising method to find conclusive evidences, which verify the electrical conductivity of DNA molecules.

This paper aims at advancing micromanipulation technology with in situ polyvinylidene fluoride (PVDF) piezoelectric force sensing during microassembly and packaging process. Based on the previously developed PVDF 1-D sensor, by employing the parallel beam structure, a novel 2-D force sensor with relatively high natural frequency and sensitivity is optimally designed. The sensor can detect micro force and force rate signals, which can be fed back so as to greatly, improve the reliability of microassembly. Preliminary calibration and experimental results on assembly of surface MEMS devices both verified the performance of the new 2-D sensor that demonstrates a high sensitivity and a resolution in the range of /spl mu/N. Ultimately the technology would provide a critical and major step towards the development of automated micro-manufacturing processes for batch assembly of micro devices.

The development of a novel polymer-based micro robotic gripper that can be actuated in a liquid medium is presented in this paper. The basic structure for the gripper is a trimorph thermal actuator with a platinum metal heater encapsulated by poly-para-xylene C (parylene C) polymer layers. Due to the large difference of thermal expansion coefficients of the different layers, the actuator can be actuated with much large deflection than conventional MEMS actuators. We have developed actuators operating in liquid environment (e.g., DI water) with only 3 V at /spl sim/33 mA input to achieve full deflection (90/spl deg/ change of tip direction). The actuators were also observed to response to 3 Hz square wave input in water with no visible delay. The temperature of the actuators at full deflection was estimated to be about 60/spl deg/C, which is much lower than the typical requirement of >100/spl deg/C to actuate other conventional MEMS actuators. Actuators with dimensions of /spl sim/2 mm/spl times/100/spl mu/m/spl times/0.6/spl mu/m were used to capture Danio rerio follicles (/spl sim/800/spl mu/m average cell diameter) in water. The design, fabrication process, and experimental results for these actuators are presented in this paper.

Heat generation is one of the major harming factors in the reaming process of the internal bone fixation surgery. In order to minimize the temperature rise of the bone during surgery, a reaming system with temperature sensation is developed to allow the real time tracking of the heat generation caused by rotational sliding friction. We have conducted experiments to calibrate and demonstrate the stability and sensitivity of the wireless transmitted temperature data. We have also analyzed the possible factors causing the temperature change of the bone cavity during surgery theoretically and performed experiments to validate these factors. An experiment was also conducted to demonstrate the sufficient penetrating power of the wireless temperature signals from a sensor inside a bone replicate.

Bundled multi-walled carbon nanotubes (MWNT) were successfully and repeatably manipulated by AC electrophoresis to form resistive elements between Au microelectrodes and were demonstrated to potentially serve as novel thermal and anemometrical sensor as well as simple electronic circuit elements. We have measured the temperature coefficient of resistance (TCR) of these MWNT bundles and also integrated them into constant current configuration for dynamic characterization. The I-V measurements of the resulting devices revealed that their power consumption were in /spl mu/W range. Besides, the frequency response of the testing devices was generally over 100 kHz in constant current mode operation. Using the same technique, bundled MWNT was manipulated between three terminal microelectrodes to form simple potential dividing device. This device was capable of dividing the input potential into 2.7:1 ratio. Based on these experimental evidences, carbon nanotube is a promising material for fabricating ultra low power consumption devices for future sensing and electronic applications. Hence, we are currently developing fast and low cost MEMS fabrication processes to incorporate carbon nanotubes as sensing elements for various types of micro sensors.

A novel bulk multi-walled carbon nanotubes (MWNT) based MEMS thermal sensor was fabricated using a polymer thin film to encapsulate MWNT sensing elements. The basic process includes AC electrophoretic manipulation of MWNT bundles on a silicon substrate and embedding them inside parylene C layers to provide a robust protection for the bundled MWNT. This encapsulation process ensures that the MWNT elements can be protected from moisture and contaminates in an operational environment, and thus, allow the sensors to be useful for potential application such as temperature measurement in water, sensing human touch and body temperature, or as ultra-sensitive sensors in manufacturing plants. We have measured the temperature coefficient of resistance (TCR) of these encapsulated MWNT-based micro sensors and also integrated them into constant current configuration for dynamic characterization. The I-V measurements of the resulting devices revealed that their power consumption were in the /spl mu/W range. Besides, the frequency response of the testing devices was generally over 100 kHz in constant current mode operation. Based on these experimental evidences, carbon nanotube is a promising material for fabricating ultra low power consumption and high frequency response micro sensors for future sensing and electronic applications.

Despite the enormous research efforts in creating new applications with MEMS, the research efforts at the backend such as packaging and assembly are relatively limited. We present our ongoing development of a polyvinylidene fluoride (PVDF) multi-direction micro-force sensing system that can be potentially used for force-reflective manipulation of micro-mechanical devices or micro-organisms over remote distances. Thus far, we have successfully demonstrated 1D and 2D sensing systems that are able to sense force information when a micro-manipulation probe-tip is used to lift a micro mass supported by 2 /spl mu/m/spl times/30 /spl mu/m/spl times/200 /spl mu/m polysilicon beams. Hence, we have shown that force detection in the 50 /spl mu/N range is possible with PVDF sensors integrated with commercial micro-manipulation probe-tips.

The ability to manipulate and control biological cells with reflective-force information is a key technology necessary for many new applications in Bio-MEMS, but is currently lacking in all cellular manipulators. We report in this paper our preliminary experimental work in using an ionic conducting polymer film (ICPF) to develop a biological cellular robotic gripper with force sensing capability. ICPF actuators are able to give large deflection with small input voltage (/spl sim/5V) in aqueous environments, and also able to give relatively large output voltage due to deflection by mechanical forces. Thus, ICPF actuators are investigated as possible cellular force-reflection controlled manipulators in our work. However, an universally accepted or accurate dynamic model for ICPF actuators does not exit yet due to the complex interdependent physical mechanisms which govern their actuation behavior electrical, chemical, and mechanical. This makes grasping control and manipulation hard ID achieve, especially if the ICPF actuators are to be used in manipulating moving biological targets. In this paper we propose a neural-fuzzy based scheme to control the movement of ICPF micro actuators.

The development of a medical surgical tool, packaged with micro sensors for transmission of supermedia information over the Internet is described in this paper. We define supermedia as a set of communication media, which encompasses acoustic, force, visual, audio, temperature, tactile, and chemical (e.g., taste and smell) information, and which can be physically experienced by a communicator. In this project, we specifically develop supermedia capability for a bone-reaming system that is used for intramedullary fixation procedure of fractured bone treatments. Thus far, transmission of temperature, force, and pressure information from MEMS sensors over the Internet has been demonstrated. Force-reflective control over the Internet using force information from a micro tip has also been shown. We have also packaged a MEMS pressure sensor inside a bone reaming guide-rod and proved that pressure variations inside a long cavity that simulated the environment inside a bone can be monitored, even with the guide-rod rotating up to 600 rpm. This paper describes our experimental methods and gives the experimental results for these accomplishments.

The ability to manipulate and control biological cells with reflective-force information is a key technology necessary for many new applications in bio-MEMS, but is currently lacking in all cellular manipulators. We report our preliminary experimental work in using an ionic conducting polymer film (ICPF) to develop a biological cellular robotic gripper with force sensing capability. ICPF actuators are able to give large deflection with small input voltage (/spl sim/5V) in aqueous environments, and also able to give relatively large output voltage due to deflection by mechanical forces. Thus, ICPF actuators are investigated as possible cellular force-reflection controlled manipulators in our work. Individual multi-finger grippers with dimensions of 200/spl mu/m /spl times/ 200/spl mu/m /spl times/ 3000/spl mu/m for each finger were realized. We report on the design, fabrication procedures, and operating performance of our ICPF actuators. Further development in the reduction of size of these actuators will enable effective force-feedback control of underwater micro objects and lead to new frontiers in cellular manipulation.

The index of the manipulative difficulty for a mobile robot towing and pushing multiple trailers to follow a straight line is proposed. It will be useful to design such a tractor-trailers system. Some examples of the manipulative difficulty index was calculated by changing the number of trailers when the mobile robot pushes and tows the trailers.