scholarly journals Soft Controllable Carbon Fibre-based Piezoresistive Self-Sensing Actuators

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 79
Author(s):  
Min Pan ◽  
Chenggang Yuan ◽  
Hastha Anpalagan ◽  
Andrew Plummer ◽  
Jun Zou ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Position Control ◽  
Control Method ◽  
Feedforward Control ◽  
The Body ◽  
Physical Contact ◽  
Sensing Element ◽  
Resistance Change ◽  
Soft Robots ◽  
Loop Control

Soft robots and devices exploit deformable materials that are capable of changes in shape to allow conformable physical contact for controlled manipulation. While the use of embedded sensors in soft actuation systems is gaining increasing interest, there are limited examples where the body of the actuator or robot is able to act as the sensing element. In addition, the conventional feedforward control method is widely used for the design of a controller, resulting in imprecise position control from a sensory input. In this work, we fabricate a soft self-sensing finger actuator using flexible carbon fibre-based piezoresistive composites to achieve an inherent sensing functionality and design a dual-closed-loop control system for precise actuator position control. The resistance change of the actuator body was used to monitor deformation and fed back to the motion controller. The experimental and simulated results demonstrated the effectiveness, robustness and good controllability of the soft finger actuator. Our work explores the emerging influence of inherently piezoresistive soft actuators to address the challenges of self-sensing, actuation and control, which can benefit the design of next-generation soft robots.

scholarly journals Feedforward Control Based on Error and Disturbance Observation for the CCD and Fiber-Optic Gyroscope-Based Mobile Optoelectronic Tracking System

Electronics ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 223 ◽  
Author(s):  
Yong Luo ◽  
Wei Ren ◽  
Yongmei Huang ◽  
Qiunong He ◽  
Qiongyan Wu ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Control Method ◽  
Feedforward Control ◽  
Tracking System ◽  
Sampling Rate ◽  
Low Frequency ◽  
Integration Time ◽  
Fiber Optic Gyroscope ◽  
Loop Control ◽  
Boresight Error

In the mobile optoelectronic tracking system (MOTS) based on charge-coupled device (CCD) and fiber-optic gyroscope (FOG), the tracking performance (TP) and anti-disturbance ability (ADA) characterized by boresight error are of equal importance. Generally, the position tracking loop, limited by the image integration time of CCD, would be subject to a non-negligible delay and low-sampling rate, which could not minimize the boresight error. Although the FOG-based velocity loop could enhance the ADA of the system, it is still insufficient in the case of some uncertain disturbances. In this paper, a feedforward control method based on the results of error and disturbance observation was proposed. The error observer (EOB) based on the CCD data and model output essentially combined the low-frequency tracking feedforward and closed-loop disturbance observer (DOB), which could simultaneously enhance the low-frequency TP and ADA. In addition, in view of the poor low-frequency performance of the FOG due to drift and noise that may result in the inaccuracy of the observed low-frequency disturbance, the FOG-based DOB was used to improve the relatively high-frequency ADA. The proposed method could make EOB and DOB complementary and help to obtain a high-precision MOTS, for in practical engineering, we give more attention to the low-frequency TP and full-band ADA. Simulations and experiments demonstrated that the proposed method was valid and had a much better performance than the traditional velocity and position double-loop control (VPDC).

Research on the Hydraulic Actuator Control of the Quadruped Robot Based Dual-Loop

2012 ◽  
Vol 569 ◽  
pp. 533-538
Author(s):  
En Chao Yang ◽  
Qing Wei ◽  
Run Bin Cai ◽  
Hong Xu Ma
Keyword(s):  
Position Control ◽  
Control Method ◽  
Quadruped Robot ◽  
Order System ◽  
Control Loop ◽  
Hydraulic Actuator ◽  
Loop Control ◽  
Actual Force ◽  
Target Force ◽  
Actuator Control

This paper presents modeling and dual-loop control of a non-linear hydraulic actuator applied on the quadruped robot. The pure position control of the actuator is hard to achieve because it’s a three-order system. So we propose the dual-loop control method to decompose it. The controller structure of the system is composed of two loops namely outer position control loop and inner force control loop. Outer loop controller is used to calculate the optimum target force to reject the errors of the position control, while, the inner loop controller is used to keep the actual force close to this desired force.

CONTROL OF VORTEX SHEDDING BEHIND A CIRCULAR CYLINDER USING ELECTROMAGNETIC FORCES

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1627-1630 ◽  
Author(s):  
ZHIHUA CHEN ◽  
BAOCHUN FAN ◽  
BENMOU ZHOU ◽  
NADINE AUBRY
Keyword(s):  
Circular Cylinder ◽  
Lorentz Force ◽  
Vortex Shedding ◽  
Closed Loop ◽  
Permanent Magnets ◽  
Control Method ◽  
The Body ◽  
Closed Loop Control ◽  
Electromagnetic Forces ◽  
Loop Control

Both open and closed loop control algorithms have been developed for manipulating wake flows past a solid cylinder in an electrically low-conducting fluid. The intent is to avoid vortex shedding and flow separation from the body, which is achieved through the introduction of localized electromagnetic forces (Lorentz forces) in the azimuthal direction generated by an array of permanent magnets and electrodes on the surface of the circular cylinder. The array of actuators offers the advantage of making the Lorentz force time and space dependent. More specifically, one closed loop control method has been derived from the equations of motion capable of determining at all times the intensity of the Lorentz force in order to control the flow. This is accomplished first, independently of the flow (open loop algorithm) and second, based on some partial flow information measured on the surface of the solid body (closed loop algorithm).

An Efficient Approach for Modeling and Control of a Quadrotor

2016 ◽  
Vol 4 (2) ◽  
pp. 1-16
Author(s):  
Ahmed S. Khusheef
Keyword(s):  
Pid Control ◽  
Control Method ◽  
Mechanical Design ◽  
Loop Control ◽  
Modeling And Control ◽  
Loop Control System ◽  
And Control ◽  
Close Loop Control ◽  
Close Loop Control System ◽  
Made In

 A quadrotor is a four-rotor aircraft capable of vertical take-off and landing, hovering, forward flight, and having great maneuverability. Its platform can be made in a small size make it convenient for indoor applications as well as for outdoor uses. In model there are four input forces that are essentially the thrust provided by each propeller attached to each motor with a fixed angle. The quadrotor is basically considered an unstable system because of the aerodynamic effects; consequently, a close-loop control system is required to achieve stability and autonomy. Such system must enable the quadrotor to reach the desired attitude as fast as possible without any steady state error. In this paper, an optimal controller is designed based on a Proportional Integral Derivative (PID) control method to obtain stability in flying the quadrotor. The dynamic model of this vehicle will be also explained by using Euler-Newton method. The mechanical design was performed along with the design of the controlling algorithm. Matlab Simulink was used to test and analyze the performance of the proposed control strategy. The experimental results on the quadrotor demonstrated the effectiveness of the methodology used.

Fast Method for the Determination of Residual Solvents in Radiopharmaceutical Products

2017 ◽  
Vol 68 (4) ◽  
pp. 666-670 ◽  
Author(s):  
Mirela Mihon ◽  
Catalin Stelian Tuta ◽  
Alina Catrinel Ion ◽  
Dana Niculae ◽  
Vasile Lavric
Keyword(s):  
Gas Chromatography ◽  
Control Method ◽  
Limit Of Detection ◽  
The Body ◽  
Biologically Active ◽  
Injection Technique ◽  
Fast Method ◽  
Residual Solvent ◽  
Residual Solvents

The aim of this work was the development and validation of a fast analytical method to determine the residual solvents content in radiopharmaceuticals such as: 18F-Fluorodeoxyglucose (18F-FDG), 18F-Fluoroestradiol (18F-FES), 18F-Fluorothymidine (18F-FLT),18F-Fluoromisonidazole (18F-FMISO). Radiopharmaceuticals are radioactive preparations for medical purposes used in nuclear medicine as tracers in diagnostic imaging and treatment of certain diseases. Positron Emission Tomography (PET) is a medical imaging technique that consists in introducing into the body of a small amount of a biologically active chemical compound labelled with a short lived positron-emitting radioisotope (18F, 11C, 68Ga). Residual solvents are critical impurities in radiopharmaceuticals that can affect labelling, stability and physicochemical properties of drugs. Therefore, the determination of these solvents is essential for quality control of radiopharmaceuticals. Validation of the control method for residual solvents by gas chromatography is referred by the European Pharmacopoeia using a special injection technique (head space). The parameters of the method, which comply with International Conference on Harmonization guidelines, are: accuracy, precision, linearity, limit of detection, limit of quantification and robustness. The proposed method (direct gas chromatography injection) proved to be linear, precise, accurate and robust. Good linearity was achieved for all the solvents and correlation coefficients (R2) for each residual solvent were found more than 0.99.

Control of coagulation process by dual wavelength article analyzer

1997 ◽  
Vol 36 (4) ◽  
pp. 135-142 ◽  
Author(s):  
Norihito Tambo ◽  
Yoshihiko Matsui ◽  
Ken-ichi Kurotani ◽  
Masakazu Kubota ◽  
Hirohide Akiyama ◽  
...  
Keyword(s):  
Water Quality ◽  
Control System ◽  
Predictive Control ◽  
Control Method ◽  
Feedforward Control ◽  
Raw Water ◽  
Floc Size ◽  
Coagulation Process ◽  
Series Of Experiments ◽  
Size Data

A coagulation process for water purification plants mainly uses feedforward control based on raw water quality and empirical data and requires operator's help. We developed a new floc sensor for measuring floc size in a flush mixer to be used for floc control. A control system using model predictive control was developed on the floc size data. A series of experiments was performed to confirm controllability of settled water quality by controlling flush mixer floc size. An automatic control with feedback from the coagulation process was evaluated as practical and reliable. Finally this new control method was applied for actual plant and evaluated as practical.

scholarly journals Backstepping Sliding-Mode Control of Piezoelectric Single-Piston Pump-Controlled Actuator

Actuators ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 154
Author(s):  
Bin Wang ◽  
Pengda Ren ◽  
Xinhao Huang
Keyword(s):  
Sliding Mode Control ◽  
Position Control ◽  
Control Method ◽  
Sliding Mode ◽  
Piezoelectric Pump ◽  
Mode Control ◽  
Control Precision ◽  
Backstepping Sliding Mode Control ◽  
Actuator System ◽  
The Mathematical Model

A piston piezoelectric (PZT) pump has many advantages for the use of light actuators. How to deal with the contradiction between the intermittent oil supplying and position control precision is essential when designing the controller. In order to accurately control the output of the actuator, a backstepping sliding-mode control method based on the Lyapunov function is introduced, and the controller is designed on the basis of establishing the mathematical model of the system. The simulation results show that, compared with fuzzy PID and ordinary sliding-mode control, backstepping sliding-mode control has a stronger anti-jamming ability and tracking performance, and improves the control accuracy and stability of the piezoelectric pump-controlled actuator system.

Register control of roll-to-roll gravure-offset printing equipment considering time difference between measurement and actuation

2012 ◽  
Vol 226 (11) ◽  
pp. 2726-2738 ◽  
Author(s):  
Chung Hwan Kim ◽  
Ha-Il You ◽  
Seung-Hyun Lee
Keyword(s):  
Measurement System ◽  
Position Control ◽  
Printed Electronics ◽  
Control Method ◽  
Axial Direction ◽  
Time Difference ◽  
Offset Printing ◽  
Drying Time ◽  
Roll To Roll ◽  
The Web

The manufacture of printed electronics by roll-to-roll printing machine requires more accurate register performance than conventional media printing technology. Moreover, high drying temperature and long drying time to sinter the inks can induce the substantial changes in the length of the substrate and consequently register errors. Among the roll-to-roll printing methods, the gravure one, despite its relatively fast productivity and fine-line printing capacity, has difficulty in achieving the required register specifications for printed electronics because of the dependence of the register control on web dynamics. This study proposes a roll-to-roll gravure-offset printing equipment, including the register measurement system designed to enhance register performance and the related register control method for the application of printed electronics. Each cylinder constituting the printing unit is driven independently by an individual servomotor. Moreover, the printing patterns of the plate cylinder can move in the axial direction by position control, as well as in the web transport direction by a phase shift of the plate cylinder, without affecting the dynamics of the web. The time difference between the measurement and the actual control action is considered and modeled. The register measurement system, including selections of sensors and marks is also proposed to consider the effect of the time difference. The simulation results and the experiments of the register control are shown to verify the effect of the time difference on the control performances. It is found that a proper estimation of time difference should be obtained in order to guarantee more accurate and stable control performances.

The Lower Extremity Exoskeleton Coordinated Control Method Based on Human Electromechanical Coupling

2012 ◽  
Vol 220-223 ◽  
pp. 1012-1017
Author(s):  
Qing Guo ◽  
Dan Jiang
Keyword(s):  
Lower Extremity ◽  
Electromechanical Coupling ◽  
Position Control ◽  
Control Method ◽  
Angular Displacement ◽  
Stability Margin ◽  
Hydraulic Cylinder ◽  
Load Force ◽  
Hydraulic Cylinders ◽  
Coupling Characteristics

This paper has introduced electromechanical coupling characteristics in the lower extremity exoskeleton systems, considered model ,according to legs supporting gait when people walking, established the load torque compensation model , and a mathematical model of knee position control system which is made of the servo valve, hydraulic cylinders and other hydraulic components, designed hydraulic cylinder position control loop in case of existing load force interference compensation, and used the method of combining the PID and lead correction network for frequency domain design ,ensured system to meet a certain stability margin. The simulation results show that this position control method can servo on the knee angular displacement of normal human walking, reached a certain exoskeleton boost effect, at the same time, met the needs of human-machine coordinated motion.

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