Large optical mirrors for space applications require accurate surface evaluation between successive corrective machining steps. Without proper compensation for self-weight, gravitational deformation can affect the measured surface figure and thereby reduce the reliability of the machining process. In this study, an air-cylinder-based gravity compensation device was developed to maintain the target support loads for large optical mirrors. A proportional–integral–derivative (PID) controller with load-cell feedback was implemented, and the initial gains obtained using the Ziegler–Nichols method were retuned on the basis of the measured system response. Single-axis experiments showed that the retuned controller met the specified performance requirements for overshoot, settling time, and steady-state error, even when applied to air cylinders with different spring reaction forces. The validated control method was then applied, via a sequential multi-channel control scheme, to a five-axis gravity compensation system to assess its applicability to multi-point gravity compensation. The experimental results confirmed stable convergence to the target support loads and effective load regulation at steady state, demonstrating that the proposed system is suitable for the multi-point gravity compensation of large optical mirrors.

Microfluidics allows for precise manipulation of small volumes of analytical solutions in diverse applications, including disease diagnostics, drug efficacy testing, chemical analysis, and water quality monitoring. Among these diverse applications, one of the most critical aspects is the precise and programmable control of flow within microfluidic control devices. However, microfluidic experiments that employ pressure control via a gas tank may encounter restricted mobility. To address these challenges, we developed an air pump feedback control system utilizing artificial intelligence image analysis and devised a method to enhance portability. In this paper, we utilized a commercially available portable pump to achieve the desired pressure and subsequently cease operation. In addressing the challenge of sustaining prolonged pressure, we implemented a strategy wherein the dimensions of the pressure vessel were modified, accompanied by iterative pump activations, thereby ensuring the sustained maintenance of pressure over time. The evaluation of the flow controller developed in this study involves conducting a comparative flow analysis with established pneumatic flow controllers. Furthermore, we employed artificial intelligence image analysis methods to automate the operation of iterative pumps. In conclusion, we anticipate that the developed portable microfluidic control device will lead to innovative advancements in modern technology and healthcare through its potential applications.

The pneumatic vibration isolator is economical, has no risk of contamination, and attains high vibration isolation performance by lowering the natural frequency. Pressure feedback control is used to improve the response speed of the pneumatic vibration isolator and keep the internal pressure of the pneumatic actuator constant. In this paper, the vibration isolator was actively controlled by estimating the internal pressure of the pneumatic actuator with the displacement signal. A pneumatic actuator was modeled and its dynamic characteristics were identified through frequency response measurements. A pressure observer based on relative displacement was designed, and the observer control gain was adjusted with nominal model and experiments. Pressure estimation performance and active vibration suppression performance using a pressure observer were verified through experiments. The pressure of the pneumatic actuator was estimated by the observer, and measurement noise was eliminated effectively. In addition, vibration isolation performances of direct and estimated pressure feedback showed no difference, verifying the effectiveness of the pressure observer.

Advances in cell culture technology have improved the understanding of the physiological principles of cells. Recently, the development of microfluidic chips has made it possible to observe single cells in a massively parallelized and accurate manner. However, in order to maximize the availability of the microfluidic cell chip, it is essential to use an incubator that can isolate the cell culture chip from the outside while minimizing contamination and maintaining the temperature and humidity required for cell culture for a long time period. Here, we developed a thermo-hygrostat incubator consisting of an Arduino-based feedback control module for controlling a temperature and humidity complex sensor, a humidifier, and a heater. The temperature and humidity of the incubator could be actively changed according to the needs and application by simple editing control variables of Arduino coding. To demonstrate the efficiency of the device, we conducted an experiment comparing the growth of bacterial cells and obtained optimal conditions necessary for culture. In conclusion, it is expected that the newly developed thermo-hygrostat incubator can be used for a variety of purposes that require active control of temperature and humidity, as well as for long-term cultivation of bacterial cells inside a microfluidic chip.

Recently, instrument stages using flexure guide mechanisms and piezo actuators have been widely used for an ultra-precision positioning system in various industries. Research into ultra-precision position control aiming at nanoscale position errors during stage driving is being actively conducted, as well as various studies on the motion profile adjusting the reference input. In this study, we suggested a motion profile with snap and feedforward for use with a high speed nano scanning system, as compared and analyzed with the position tracking error through feedback control, and also compared to the related feed with the forward control noted as minimized at the position error to 14.19 nm. As a result, a tracking error when applying the fourth profile with snaps to the piezoelectric stage, is obtained with an error reduction effect of about 15%, as compared to when the second profile is applied.

The purpose of this study was to develop and verify the smart insole based FSR sensor for measurement and improvement of the muscle strength imbalance. We recruited 15 subjects with muscle strength difference over 20% and 15 subjects with muscle strength balance below 10%. We developed the human body load insole and integrated modules using FSR sensor. Subjects walked for 5 minutes at a slope of 0% and a speed of 3 km / h on a treadmill with a smart insole. We measured the real-time muscle activity and foot pressure according to the muscle strength imbalance during gait. FSR data of the developed smart insole showed that the insole had similar accuracy and efficacy as muscle activity and foot pressure. This is the interval in which the muscle imbalance shifts from the stance phase to the load reaction, and the weight support is the largest, and the center of gravity of the human body passes over the whole foot, which is considered to cause the greatest imbalance. This suggests that there is a direct or indirect correlation between muscle strength imbalance of the lower limb and the imbalance of the body weight distribution during gait.

This paper describes the efficient equipment maintenance that can offer the exact time for repair and change of component in root industry. A conventional method offered the fixed time for repair and change of component because the method is based on early guarantee specification of the component. However the operating condition of manufacturing field is often under worse condition than early guarantee condition for high productivity. So, most components can’t use until early guarantee time due to the operation of various different condition. Therefore we suggest the useful method for efficient equipment-maintenance by manufacturing-field analysis and feedback database. For this, the classification of root industry and related equipment is performed and then the detail classification of the process and component for equipment maintenance. And the monitoring module is also designed to gather data for feedback process and the environment is basically implemented for aging and reliability test.