• Journal of KSNVE
• /
• v.2 no.1
• /
• pp.49-59
• /
• 1992

The motion analysis of a translation device driven by a piezoelectric actuator is performed to identify the mechanics of impact drive mechanism and to find the maximum speed waveform. The translation device is modeled as a semidefinite two-degree-of-freedom system. The motion analysis includes effects of friction force between moving mass and contact surface, dynamics of voltage amplifier and piezoelectric elements, and hysteresis of piezoelectric actuator. Base on the model, simulation studies are carried out and then compared with experimental results. It is found that the error between moving distances obtained by analysis and experiment is less than 15% and that the actual motion of moving mass is well predicted by the analytical work, finally, precision positioning experiments are carried out by using a proximity sensor as a feedback sensor. Position control of moving mass is initiated by the maximum speed waveform and finely tuned by the scaled down waveform so that accurate positioning is accomplished within the resolution of the sensor.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.11 no.3
• /
• pp.231-238
• /
• 2017

In this paper, we propose a method of analyzing exercise behavior to increase health care and exercise effect in personal fitness. In this study, a user wears a band-shaped acceleration sensor, an angular velocity sensor, and a motion sensor equipped with a geomagnetic module. Using the technique presented in this paper, we analyzed the motion of three resistive exercises which is consistent with previous studies. We have acquired a technique for processing personalized exercise information from the data generated in the resistive exercise situation.

• Proceedings of the KIEE Conference
• /
• 2004.11c
• /
• pp.583-585
• /
• 2004

In this paper we will deal with a calibration method for low cost motion capture system using psd(position sensitive detection) optical sensor. To measure the incident direction of the light from LED emitted marker, the PSD is used the output current ratio on the electrode of PSD is proportional with the incident position of the light focused by lens. In order to defect the direction of the light, the current output is converted into digital voltage value by opamp circuits peak detector and AD converter with the digital value the incident position is measured. Unfortunately, due to the non-linearly problem of the circuit poor position accuracy is shown. To overcome such problems, we compensated the non-linearly by using least-square fitting method. After compensated the non-linearly in the circuit, the system showed more enhanced position accuracy.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.12
• /
• pp.146-153
• /
• 2009

One of the most important issues in the wearable healthcare sensors is to minimize the motion artifacts in the vital signals for continuous monitoring. This paper presents a reflected type photoplethysmograph (PPG) sensor for monitoring heart rates at the artery of the wrist. Active noise cancellation algorithm was applied to compensate the distorted signals by motions with Least Mean Square (LMS) adaptive filter algorithms, using acceleration signals from a MEMS accelerometer. Experiments with a watch type PPG sensor were performed to validate the proposed algorithm during typical daily motions such as walking and running. The developed sensor is suitable for ubiquitous healthcare system and monitoring vital arterial signals during surgery.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.6
• /
• pp.1127-1134
• /
• 2017

In this study, the robot arm control system was implemented that is operated by human hands, which can be used in environments that are inaccessible to humans. This function has to be sent to the robot's arms after extracting coordinates of human hands. Through mapping and bluetooth communication we use a leap motion sensor with infrared light and Image recognition sensor.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.679-684
• /
• 1993

This article presents an approach to estimate the general 3D motion of a polyhedral object using multiple, sensory data some of which may not provide sufficient information for the estimation of object motion. Motion can be estimated continuously from each sensor through the analysis of the instantaneous state of an object. We have introduced a method based on Moore-Penrose pseudo-inverse theory to estimate the instantaneous state of an object. A linear feedback estimation algorithm is discussed to estimate the object 3D motion. Then, the motion estimated from each sensor is fused to provide more accurate and reliable information about the motion of an unknown object. The techniques of multisensor data fusion can be categorized into three methods: averaging, decision, and guiding. We present a fusion algorithm which combines averaging and decision.

• Journal of Sensor Science and Technology
• /
• v.29 no.5
• /
• pp.312-322
• /
• 2020

As the use of mobile devices increase, there is public interest in the utilization of the human motion generated mechanical energy. The human motion generated mechanical energies vary depending on the body region, type of motion, etc., and an appropriate device has to be designed to utilize them effectively. In this work, a device based on the principles of triboelectric generation and inertia was assessed in order to utilize the multi-axial mechanical energies generated by human motions. To improve the output performance we confirm the changes in the output that vary with the structural design, the reasons for such changes, and variations in performance based on the parts of the human body. In addition, the level of electrical energy generated based on motion type was measured; a maximum voltage of 30 V and a current of 2 ㎂ were generated. Finally, the proposed device was utilized in LEDs used for lighting, thus demonstrating that multi-axial mechanical energies can be harvested effectively. Based on the results, we expect that the developed device can be utilized as a sensor to detect mechanical energies, to sense changes in motion, or as a generator for auxiliary power supply for mobile devices.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.6 s.171
• /
• pp.30-39
• /
• 2005

• IEMEK Journal of Embedded Systems and Applications
• /
• v.5 no.2
• /
• pp.46-56
• /
• 2010

This study proposes a monitoring system by cooperating the image information and the sensor information in a sensor network system. The monitoring system proposed in this study is divided into internal spaces, such as offices and laboratories, and external spaces including other various spaces. In the internal spaces, motions in objects are detected through cameras while some peripherals like lights are controlled by analyzing some temperature, humidity, and illuminance data detected by sensor nodes. In the external spaces, it is to watch certain intruders to the internal spaces through the interested region for exceptional time by installing cameras, motion detectors, and body detectors in such interested regions. In the results of the test that was applied to a practically limited environment by implementing some interfaces for the proposed system, it was considered that it is possible to watch surroundings effectively using the image information obtained from cameras and sensor information acquisited from sensor nodes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.778-783
• /
• 2003

The problem considered in this paper is about the collocation of sensor and actuator for the active control of sound and vibration. It is well-known that a point collocated sensor-actuator pair offers an unconditional stability with very high performance when it is used with a direct velocity feedback (DVFB) control, because the pair has strictly positive real (SPR) property. In order to utilize this SPR characteristics, a matched piezoelectric sensor and actuator pair is considered, but this pair suffers from the in-plane motion coupling problem with the out-of$.$plane motion due to the piezo sensor and actuator interaction. This coupling phnomenon limits the stability and performance of the matched pair with DVFB control. As a new alternative, a point sensor and piezoelectric actuator pair is also considered, which provides SPR property in all frequency range except at the first resonance in very low frequency. This non-SPR resonance could be minimized by applying a phase lag compensator.