Underwater Flexible Manipulator Double-Loop Feedback Control Based on Built-in Binocular Vision and Displacement Sensor

Abstract A real-time and effective double-loop feedback control system for underwater flexible manipulators is raised in this paper. The research object is a kind of underwater flexible manipulator driven by McKibben water hydraulic artificial muscle (WHAM) that can grasp, swallow, and disgorge target objects in its interior space. To make up for the lack of flexibility, an underwater flexible manipulator collaborative working strategy is proposed. A more flexible and smaller flexible manipulator is placed inside the flexible manipulator to assist it in performing difficult underwater works. The control system feeds back the position of internal objects through a built-in binocular camera and the working state of the manipulator through displacement sensors. The control system setups including underwater flexible manipulator subsystem, hydraulic drive subsystem, PLC control subsystem, displacement sensor subsystem, built-in binocular vision subsystem, and upper computer subsystem is built. PYTHON-based built-in binocular vision software and C++-based underwater flexible manipulator control software are also developed to facilitate observation and recording. The underwater flexible manipulator collaborative experiment is designed to verify the performance of the control system and the control algorithm.

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Stability analysis in machining process by using adaptive closed-loop feedback control system in turning process

Journal of Vibration and Control ◽

10.1177/1077546320952613 ◽

2020 ◽

pp. 107754632095261

Author(s):

Kashfull Orra ◽

Sounak K Choudhury

Keyword(s):

Control System ◽

Feedback Control ◽

Closed Loop ◽

Machining Process ◽

Feedback Control System ◽

Turning Process ◽

Tool Vibration ◽

Loop Feedback ◽

Closed Loop Feedback ◽

The Stability

The study presents model-based mechanism of nonlinear cutting tool vibration in turning process and the strategy of improving cutting process stability by suppressing machine tool vibration. The approach used is based on the closed-loop feedback control system with the help of electro–magneto–rheological damper. A machine tool vibration signal generated by an accelerometer is fed back to the coil of a damper after suitable amplification. The damper, attached under the tool holder, generates counter forces to suppress the vibration after being excited by the signal in terms of current. The study also discusses the use of transfer function approach for the development of a mathematical model and adaptively controlling the process dynamics of the turning process. The purpose of developing such mechanism is to stabilize the machining process with respect to the dynamic uncut chip thickness responsible for the type-II regenerative effect. The state-space model used in this study successfully checked the adequacy of the model through controllability and observability matrices. The eigenvalue and eigenvector have confirmed the stability of the system more accurately. The characteristic of the stability lobe chart is discussed for the present model-based mechanism.

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Operator-Based Robust Nonlinear Control Design of a Robot Arm with Micro-Hand

Journal of Robotics and Mechatronics ◽

10.20965/jrm.2016.p0568 ◽

2016 ◽

Vol 28 (4) ◽

pp. 568-578 ◽

Cited By ~ 1

Author(s):

Zhengxiang Ma ◽

◽

Aihui Wang ◽

Tiejun Chen ◽

Keyword(s):

Control System ◽

Feedback Control ◽

Nonlinear Control ◽

Angular Position ◽

Control Design ◽

Robot Arm ◽

Robust Nonlinear Control ◽

Precise Position ◽

Control Scheme ◽

Loop Feedback

[abstFig src='/00280004/14.jpg' width='300' text='Robot arm with micro-hand system' ] This work focuses on a robust nonlinear control design of a robot arm with micro-hand (RAMH) by using operator-based robust right coprime factorization (RRCF) approach. In the proposed control system, we can control the endpoint position of robot arm and obtain the desired force of micro-hand to perform a task, and a miniature pneumatic curling soft (MPCS) actuator which can generate bidirectional curling motions in different positive and negative pressures is used to develop the fingers of micro-hand. In detail, to control successively the precise position of robot arm and the desired force of three fingers according to the external environment or task involved, this paper proposes a double-loop feedback control architecture using operator-based RRCF approach. First, the inner-loop feedback control scheme is designed to control the angular position of the robot arm, the operator controllers and the tracking controller are designed, and the robust stability and tracking conditions are derived. Second, the complex stable inner-loop and micro-hand with three fingers are viewed as two right factorizations separately, a robust control scheme using operator-based RRCF approach is presented to control the fingers forces, and the robust tracking conditions are also discussed. Finally, the effectiveness of the proposed control system is verified by experimental and simulation results.

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Development of a New Type 4D Dynamic Seat Platform Control System Based on PLC

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.475-476.776 ◽

2013 ◽

Vol 475-476 ◽

pp. 776-781

Author(s):

Qing Kui Chen ◽

Yu Long Chen

Keyword(s):

Control System ◽

Linear Displacement ◽

Displacement Sensor ◽

Hydraulic Pump ◽

Cost Performance ◽

Loop Feedback ◽

New Type ◽

Working Principle ◽

Closed Loop Feedback ◽

Seat Control

This article has introduced the development method of a kind of 4d cinema dynamic seat control system based on PLC, expounds the system's hardware structure , working principle, function characteristics, etc. The system's power is provided by hydraulic pump, hardware adopts closed loop feedback control system constituted by omron PLC, A/D module, D/A module, linear displacement sensor and electromagnetic proportional directional valve. The system has good stability, high cost performance, miniaturization, intelligent, etc.

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The Study of Hydraulic Valve Position Control Based on PLC Controller

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.651-653.928 ◽

2014 ◽

Vol 651-653 ◽

pp. 928-931

Author(s):

Chun You Zhang ◽

Cong Rui Wang

Keyword(s):

Control System ◽

Automatic Control ◽

Closed Loop ◽

Position Control ◽

Angular Displacement ◽

Hydraulic Drive ◽

Displacement Sensor ◽

Prototype Model ◽

Valve Position ◽

Hydraulic Valve

With the growing shortage of water today, in order to control the flow of pipe conveyance, it is essential for further study of automatic control valves, especially the automatic control technology of control valve. In this paper, by using programmable control and signal transmission technologies etc. a prototype model of hydraulic valve position control is constructed. Prototype model is designed as the closed-loop of position control system, by using high-precision angular displacement sensor detecting the position of the valve plate, converting the output signal of sensor into an industrial process signal 4-20mA with the low-drift transmitter chip XTR101, and with modular PLC as system control center, using three-phase inverter controlling the steering and speed of motor and cooperating with closed pump control system for hydraulic drive, it achieves the closed-loop control hydraulic valve position. This paper provides some technical support for the better use of water resources.

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The Frequency-Domain Fusion Virtual Multi-Loop Feedback Control System with Measured Disturbance Feedforward Method in Telescopes

Electronics ◽

10.3390/electronics8101103 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1103 ◽

Cited By ~ 2

Author(s):

Yao Mao ◽

Jiuqiang Deng ◽

Xi Zhou ◽

Wei Ren

Keyword(s):

Control System ◽

Feedback Control ◽

Frequency Domain ◽

Image Sensor ◽

Feedback Control System ◽

Structural Vibrations ◽

Optical Telescope ◽

Mems Accelerometer ◽

Domain Fusion ◽

Loop Feedback

In the optical telescope, the stable precision of the optical path is affected by the structural vibrations. The image sensor with time delay and the micro electro-mechanical system (MEMS) accelerometer with massive drift limit the disturbance suppression performance of the closed loops. The current control methods cannot reject sufficiently vibrations due to the deficiency of the sensors, causality, and stability restrictions. In this study, the frequency-domain fusion virtual multi-loop feedback control system with measured disturbance feedforward method is proposed to suppress more structural vibrations. In spite of the deficiency of the sensors, we propose the frequency-domain fusion virtual gyroscopes (VGYR) to measure extra velocity of the system. The VGYR is estimated from the MEMS accelerometer with drift and corrected by the image sensor, and it replaces the fiber-optical gyroscopes (FOG) on the fast-stable platform because the weight of FOG is not negligible. To suppress more vibrations, the VGYR and the replaced FOG are utilized to build the virtual multi-loop feedback control system with measured disturbance feedforward, because it is not limited by the causality and stability restrictions. Therefore, the proposed method with causal ideal compensator can effectively improve stable precision and suppress much more structural vibrations in the wider frequency range. Detailed comparative experimental results adequately illustrate the advantages and effectiveness of this method.

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