Showing papers by "Jianqing Wang published in 2019"

Development of an Immunity Test System With a Pseudo Biosignal Generator for Wearable Devices and Application to the ESD Test of an Artificial Hand

Abstract: In this study, we developed an immunity test system for wearable devices used for healthcare or assistance to people with disabilities. The immunity test system consists of a pseudo biosignal generator for generating various vital signals such as electrocardiogram or electromyography and a bioequivalent gel phantom for simulating a part of the human body. As an application to the electrostatic discharge (ESD) immunity test for a myoelectric artificial hand, we used the pseudo biosignal generator to generate various myoelectric signals and confirmed a high correlation between the generated and the real myoelectric signals. We then applied this system to the IEC61000-4-2 specified ESD test. Through a comparison between the ESD test results by using the immunity test system and the result for a real human body, we found a high similarity between them, which suggests that the proposed immunity test system is feasible for various immunity tests in wearable devices.

Wireless Control of Robotic Artificial Hand Using Myoelectric Signal Based on Wideband Human Body Communication

Abstract: A Myoelectric hand is a robotic artificial hand controlled by myoelectric signals and driven by motors. The myoelectric signals are detected on the arm and sent to the motor controller by wire for driving the artificial hand. However, from the point of view of convenience, wireless connection between the myoelectric signal detector and the motor controller is strongly desired. In this paper, we developed a human body communication-based wireless transmitter and receiver for transmitting the myoelectric signals from the arm to the motor controller of the myoelectric hand. The transmitter and the receiver employed a wideband impulse radio system at about 10-50-MHz extremely weak radio power band and were implemented on a field programmable gate array, respectively. The feasibility of the wireless myoelectric hand was confirmed by a wireless transmission experiment of myoelectric signals and an operation experiment of the myoelectric hand. The wireless transmission experiment achieved a correlation coefficient as high as 0.999 between the transmitted and received myoelectric signals, and the operation experiment demonstrated a normal movement of the myoelectric hand controlled by the wireless myoelectric signals. This result should be the first realization example of wireless control of a robotic artificial hand based on human body communication technology.

Motion-Induced Imbalance of Contact Impedance in ECG Capture: Comparison of Electrode Materials in Capacitive Coupling

Abstract: Differences in contact impedance of the ECG measurement electrodes lead to asymmetries of the signal paths and thus result in reduced common-mode rejection and artifacts. Here, the imbalance of contact impedance is investigated for different types of electrodes with capacitive coupling in terms of static imbalance as well as dynamic variation during body movement. Flexible and incompressible materials like conductive foam and fabric showed the best overall performance. The negative effect of rigidity can partly be compensated by adding conducting foam, while soft materials can profit from an increase of electrode area.

HBC-UWB Channel Modeling for In-body to On-body Communication Link

Abstract: Human Body Communication (HBC) uses the human body as a transmission medium, providing a new means for data transfer for body area networks (BANs). On the other hand, to improve low-profile high data rates communication performance for in-body to on-body (IB2OB) links, Ultra-Wideband (UWB) technology is a preferable candidate. Hence, in this work, channel characteristics based on HBC-UWB signals (10-50 MHz) for typical in-body to on-body links, such as heart, brain, arm, small intestine to sensor nodes attached on the body surface, are investigated to derive a comprehensive a path-loss model using an anatomical human model. The results show that a linear regulation term related to surface wave propagation should be added to construct a more accurate IB2OB path-loss model. The shadow fading is normally distributed around the derived mean path-loss. Moreover, the key parameters for channel characterization are summarized to provide useful insight for developing HBC-UWB implant communication system.

Circuit Design for Common-mode Noise Rejection in Biosignal Acquisition based on Imbalance Cancellation of Electrode Contact Resistance

Abstract: Common-mode (CM) noise is a primary interference to biological signal (biosignal) detection systems but is hardly solved with passive filtering. Conventionally, a driven-right-leg (DRL) circuit is employed to drive down the CM noise level. In this paper, we proposed a novel design of biosignal acquisition circuit based on canceling the imbalance between contact resistances of detection electrodes and made a comparison with the DRL circuit. We first theoretically analyzed how it works in rejecting the CM noise. Then we conducted circuit simulation and the result indicates that our design could realize a common-mode rejection of as high as 200 dB in experimental condition, which is better than the simulated DRL circuit.

Dual-Band Monopole-Helix Antenna System for MHz-Band Implant Body Area Networks

Abstract: A miniaturized dual-band antenna system is proposed for body area networks (BANs) at MHz-band. The implant transmitting antenna has a monopole-helix structure with unequal pitch angle, and a flexible magnetic sheet is used as substrate to realize antenna miniaturization. The receiving antenna has a planar monopole-spiral structure with two stacked layers of FR-4. The proposed implant antenna is fabricated and evaluated by the receiving antenna in a muscle-equivalent phantom. Measured −10 dB impedance bandwidth is 22.43-23.48 MHz and 43.08-48.46 MHz at two resonant frequencies of 22.8 MHz and 45.6 MHz, respectively. Simulation and measurement results demonstrate that the proposed dual-band antenna system is stable and suitable for high-speed implant transmission at MHz-band.

Noncontact Measurement Method for High-Frequency Impedance of Load at the End of Wire Harness

Abstract: Request for a noncontact measurement method of load impedance connected to a wire harness is increasing rapidly. A method using a network analyzer together with two current probes was previously proposed for this purpose, but it is valid only to $20\text{--}$ 30 MHz. In this study, we extended the above-mentioned noncontact measurement method to an FM band by applying a transmission line theory to the wire harness. The validity of the newly proposed measurement method was confirmed experimentally, and as a result the load impedance was measured with an error within 10% up to 100 MHz.