scholarly journals Analyses of the Temperature Field of a Piezoelectric Micro Actuator in the Endoscopic Biopsy Channel

2019 ◽  
Vol 9 (21) ◽  
pp. 4499 ◽  
Author(s):  
Zhu ◽  
Peng ◽  
Yang
Keyword(s):  
Human Body ◽  
Control Method ◽  
Safety Issue ◽  
Endoscopic Biopsy ◽  
Duty Ratio ◽  
Driving Voltage ◽  
Operation Condition ◽  
Micro Actuator ◽  
Fem Method ◽  
Biopsy Channel

Micro actuators have been used to realize the arrival of digestive tract lesions for the local targeted application of drugs in endoscopes. However, there still exists a key safety issue that casts a shadow over the practical and safe implementation of actuators in the human body, namely an overheated environment caused by actuators’ operation. Herein, with the aim of solving the temperature rising problem of a piezoelectric micro actuator operating in an endoscopic biopsy channel (OLYMPUS, Tokyo, Japan), a thermal finite element method (FEM) based on COMSOL Multiphysics software is proposed. The temperature distribution and its rising curves are obtained by the FEM method. Both the simulated and experimental maximum temperatures are larger than the safety value (e.g., 42 °C for human tissues) when the driving voltage of the actuator is 200 Vpp, which proves that the overheating problem really exists in the actuator. Furthermore, the results show that the calculated temperature rising curves correspond to the experimental results, proving the effectiveness of this FEM method. Therefore, we introduce a temperature control method through optimizing the duty ratio of the actuator. In comparison with a 100% duty ratio operation condition, it is found that a 60% duty ratio with a driving voltage of 200 Vpp can more effectively prevent the temperature rising issue in the first 3 min, as revealed by the corresponding temperatures of 44.4 and 41.4 °C, respectively. When the duty ratio is adjusted to 30% or less, the temperature rise of the actuator can be significantly reduced to only 36.6 °C, which is close to the initial temperature (36.4 °C). Meanwhile, the speed of the actuator can be well-maintained at a certain level, demonstrating its great applicability for safe operation in the human body.

scholarly journals Application and Control Method of Electromagnetic Synchronizer for Double Rotor Motor Power Coupling System

2016 ◽  
Vol 19 (2) ◽  
pp. 88
Author(s):  
Jiang Kejun ◽  
He Ren ◽  
Zhang Lanchun
Keyword(s):  
Pid Control ◽  
Control Method ◽  
Electromagnetic Coupling ◽  
Duty Ratio ◽  
Driving Voltage ◽  
Motor Power ◽  
Power Coupling ◽  
Coupling System ◽  
Optimal Pid Control ◽  
The Impact

On the double rotor motor power coupling system existing now, electromagnetic coupling of the inner motor is the only way to transmit engine power to drive axle. And this leads to the low transmission efficiency when the vehicle is driven by the engine. Aiming at this issue, this paper proposes the improvement measure, which is to add the electromagnetic synchronizer between the input shaft and the output shaft. According to the thinking of this measure, the paper analyzes the operating process of the electromagnetic synchronizer. Then using quadratic optimal control theory, the optimal PID control method is designed to control the duty ratio of the electromagnetic synchronizer driving voltage. In order to test the validity of the method, the paper builds the simulation model in Matlab/Simulink software. The simulation results indicate that the optimal PID control method can effectively control the work process of electromagnetic synchronizer. It can achieve the balance between frictional work and longitudinal jerk, and decrease the impact reasonably when the electromagnetic synchronizer switching its state.

Electric Wheelchair Controlled by Human Body Motion -Classification of Body Motion and Improvement of Control Method-

2010 ◽  
Vol 22 (4) ◽  
pp. 439-446 ◽  
Author(s):  
Sho Yokota ◽  
◽  
Hiroshi Hashimoto ◽  
Yasuhiro Ohyama ◽  
Jinhua She ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Human Body ◽  
Control Method ◽  
Body Movement ◽  
Single Point ◽  
Movement Pattern ◽  
Body Motion ◽  
Self Organizing Map ◽  
Electric Wheelchair ◽  
Wheelchair Control

This paper classifies human body movements when an electric wheelchair was controlled using a Human Body Motion Interface (HBMI) by a Self-Organizing Map (SOM) and proposes control based on classification results. The Human Body Motion Interface (HBMI) uses body movement following voluntary motion. This study focuses on electric wheelchair control as an application of the HBMI. The viability of the HBMI was confirmed using Center Of Weight (C.O.W.) from pressure distribution information on backrest in the wheelchair to control it. If body movement concentrated on a single point at C.O.W. in pressure distribution, a problem occurred because the system would recognize even different body-movement patterns as the same movement. We call body movement taking the same C.O.W. even if it has a different body-movement pattern movement confusion. We solve the movement confusion problem and enhance wheelchair control, classifying body movement using the SOM and reflecting this classification result to improve wheelchair control. Experimental results showed that movement confusion is solved and wheelchair control improved.

scholarly journals Optimized Modeling and Control Strategy of the Single-Phase Photovoltaic Grid-Connected Cascaded H-bridge Multilevel Inverter

Electronics ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 207 ◽  
Author(s):  
Seongjun Lee ◽  
Jonghoon Kim
Keyword(s):  
Single Phase ◽  
Control Method ◽  
Maximum Power ◽  
Multilevel Inverter ◽  
Duty Ratio ◽  
Control Loop ◽  
Partial Shading ◽  
Modeling And Control ◽  
Photovoltaic Array ◽  
And Control

This paper presents the modeling and control-loop design method with an inverted decoupling scheme of a single-phase photovoltaic grid-connected five-level cascaded H-bridge multilevel inverter. For the unity power factor, the proportional and integral current controller with a duty ratio feed-forward compensation is used. In addition, in order to achieve the maximum power point tracking of each photovoltaic array, when the stacked modules are in the partial shading condition, each direct current (DC) voltage is stably controlled to their maximum power points (MPP) by dedicated voltage controllers of each H-bridge module. This paper also presents a control method that minimizes the effect of the loop-interaction in the design of an individual DC-link voltage control loop in a two-input two-output system. The proposed control methods of the cascaded H-bridge multilevel inverter are validated through the simulation and experimental results of the 2-kW prototype hardware.

scholarly journals Assessment of method for measuring clo value using human body – Assessment of method for measuring clo value that assumes human body temperature adjustment

2019 ◽  
Vol 111 ◽  
pp. 06050
Author(s):  
Yoshiaki Yamato ◽  
Yoshihito Kurazumi ◽  
Kenta Fukagawa ◽  
Kunihito Tobita ◽  
Emi Kondo
Keyword(s):  
Heat Loss ◽  
Constant Temperature ◽  
Temperature Control ◽  
Human Body ◽  
Measurement Method ◽  
Heat Dissipation ◽  
Control Method ◽  
Thermal Manikin ◽  
Constant Heat ◽  
Human Body Temperature

In order to make it possible to measure the clo value in various postures, we are studying the measurement method using the human body. Our previous researches showed that clo value measured with the human body is less than that measured with a “constant temperature control”-type thermal manikin. In our previous experiments, human body changes its skin temperature in response to the amount of clothing or changes in the temperature to maintain heat loss, while a “constant temperature control”-type thermal manikin changes its heat loss in response to the temperature or amount of clothing. Human body reaction is similar to “constant heat dissipation” -type thermal manikin. In order to improve the clo value measurement method using the human body, clo value of same clothing by thermal manikin which changed control method to “constant temperature” and “constant heat dissipation” were measured. Relational expressions of thermal insulation of clothes measured by different control methods were shown.

scholarly journals AI based Vector Control Method for BLDC Motor with Multi Switch Three-Phase Topology

2021 ◽  
Vol 58 (1) ◽  
pp. 3132-3141
Author(s):  
Ch. Vinay Kumar, G. Madhusudhana Rao, A. Raghu Ram
Keyword(s):  
Neural Network ◽  
Control Method ◽  
Constant Load ◽  
Control Technique ◽  
Duty Ratio ◽  
Bldc Motor ◽  
Speed Sensor ◽  
Neural Network Controller ◽  
The Neural Network ◽  
Coupling System

Brushless direct current (BLDC) Motors are extensively used because of their characteristics. Such characteristics are high dynamic response and high-power density.  BLDCM control system is a nonlinear, multi-variable, strong-coupling system. In this paper it is proposed that a neural network controller is used for the five level switch of the BLDC motor to enhance the power factor and reduce the current distortions with respect to its rise time, startup torque. This method is also done in comparison with the PID controllers. The working principle of the BLDC is with the help of five-switch control scheme can be implemented here. The different values of load were used to consider the total operation of the BLDC motor is to be controlled. After the completion of the training and testing of the neural network, it might be maintain the constant load values and its variables. To calculate the duty ratio of the DC-DC converter, it will be adjusted to regulate the speed of the BLDC motor. However the DC link of the five switching inverter is used here for the boosting of the voltage.  The effectiveness of the proposed control technique can be realized with help of the speed sensor. Various tests have been conducted in the simulation the proposed technology is the robust technology and it is proven that very effective and suitable control technique. 

Development and Attitude Control of Flexible Robot Arm Using Flexible Pneumatic Cylinder with Simple Structure

2011 ◽  
Vol 5 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Tetsuya Akagi ◽  
◽  
Shujiro Dohta ◽  
Feifei Zhao ◽  
Takahiro Fujikawa
Keyword(s):  
Analytical Model ◽  
Human Body ◽  
Attitude Control ◽  
Simple Structure ◽  
Control Method ◽  
Control Valve ◽  
Pneumatic Cylinder ◽  
Robot Arm ◽  
Flexible Robot ◽  
Servo Valve

A wearable actuator needs to be flexible so as not to injure the human body. The purpose of our study is to develop a flexible and lightweight actuator which can be safe enough to be attached to the human body, and to apply it to a robot arm and rehabilitation device. New types of flexible pneumatic actuator that can be used even if the actuator is deformed by external force have been developed in our previous studies. In this paper, a robot arm using the flexible pneumatic cylinder that can realize a natural flowing movement with multi-motion such as bending, expanding, and contracting is described. The analytical model of the robot arm is proposed for attitude control. In addition, an inexpensive quasi-servo valve using the on/off control valve is utilized in the master-slave control system to improve the control performance. As a result, the usability of the proposed robot arm and the effectiveness of the attitude control method using the analytical model and the quasi-servo valve are confirmed.

scholarly journals Model Predictive Control Method with Constant Switching Frequency to Reduce Common-Mode Voltage for PMSM Drives

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hao Li ◽  
Shuo Chen ◽  
Xiang Wu ◽  
Guojun Tan
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Control Method ◽  
Control Period ◽  
Duty Ratio ◽  
Switching Frequency ◽  
Common Mode ◽  
Common Mode Voltage ◽  
Control Frequency ◽  
Finite Control

A model predictive control method to reduce the common-mode voltage (MPC-RCMV) with constant switching frequency for PMSM drives is proposed in this paper. Four nonzero VVs are adopted in future control period and the switching sequence is designed to ensure the switching frequency is fixed and equal to the control frequency. By substituting the finite-control nonzero voltage vectors in the current predictive model, a current predictive error space vector diagram is obtained to determine the adopted four VVs. The duty ratio calculating method for the selected four VVs is studied. Compared with the conventional MPC-RCMV method, the current and torque ripples are greatly reduced and the switching frequency is fixed. The simulation and experiment results validate the effectiveness of the proposed method.

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