Magnetic control of continuum devices

2017 ◽  
Vol 36 (1) ◽  
pp. 68-85 ◽  
Author(s):  
Janis Edelmann ◽  
Andrew J Petruska ◽  
Bradley J Nelson
Keyword(s):  
Closed Loop ◽  
Numerical Solutions ◽  
Control Method ◽  
Open Loop ◽  
Stabilizing Controller ◽  
Loop Control ◽  
Boundary Constraints ◽  
Stable Direction ◽  
Magnetic Components ◽  
Equilibrium Configurations

In this paper we apply Cosserat rod theory to catheters with permanent magnetic components that are subject to spatially varying magnetic fields. The resulting model formulation captures the magnetically coupled catheter behavior and provides numerical solutions for rod equilibrium configurations in real-time. The model is general, covering cases with different catheter geometries, multiple magnetic components, and various boundary constraints. The necessary Jacobians for quasi-static, closed-loop control using an electromagnetic coil system and a motorized advancer are derived and incorporated into a visual-feedback controller. We address the issue of solution bifurcations caused by the magnetic field by proposing an additional, stabilizing control method that makes use of system redundancies. We demonstrate the effectiveness of the model by performing 3D tip-position trajectories with root-mean-square distance errors of 2.7 mm in open-loop, 0.30 mm in closed-loop, and 0.42 mm in stabilizing closed-loop modes. The stabilizing controller achieved on average a factor of 1.6 increase in the restoring wrenches for the least stable direction.

ADAPTIVE OPEN-PLUS-CLOSED-LOOP CONTROL METHOD OF MODIFIED FUNCTION PROJECTIVE SYNCHRONIZATION IN COMPLEX NETWORKS

2011 ◽  
Vol 22 (12) ◽  
pp. 1393-1407 ◽  
Author(s):  
HONGYUE DU
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Open Loop ◽  
Projective Synchronization ◽  
Closed Loop Control ◽  
Loop Control ◽  
Function Projective Synchronization ◽  
Advantages And Disadvantages ◽  
Modified Function Projective Synchronization ◽  
Loop Feedback

This paper investigates the modified function projective synchronization (MFPS) in drive-response dynamical networks (DRDNs) with different nodes, which means that systems in nodes are strictly different. An adaptive open-plus-closed-loop (AOPCL) control method is proposed, which is a practically realizable method and can overcome the model mismatched to achieve synchronization. It is well known that each of the close-loop and open-loop control method possesses some advantages and disadvantages. By combining their advantages, the open-plus-closed-loop (OPCL) control method was proposed by Jackson and Grosu. For arbitrary nonlinear dynamic systems, dx/dt = F(x,t), Jackson and Grosu proved that there exists solutions, x(t), in the neighborhood of any arbitrary goal dynamics g(t) that are entrained to g(t), through the use of an additive controlling action, K(g,x,t) = H(dg/dt,g) + C(g,t)(g(t) - x), which is the sum of the open-loop action, H(dg/dt,g), and a suitable linear closed-loop (feedback) action C(g,t). This method is a practically realizable method and robust to limited accuracy of data and effects of noise. The AOPCL control method preserve the merits of OPCL control method and its closed loop control part can be automatically adapted to suitable constants. Considering time-delays are always unavoidably in the practical situations, MFPS in DRDNs with time-varying coupling delayed is further investigated by the proposed method. Corresponding numerical simulations are performed to verify and illustrate the analytical results.

A New Close-Loop Control Method for an Inspection Robot Equipped with Electropermanent-Magnets

2016 ◽  
Vol 28 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Pakpoom Kriengkomol ◽  
◽  
Kazuto Kamiyama ◽  
Masaru Kojima ◽  
Mitsuhiro Horade ◽  
...  
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Steel Structures ◽  
Open Loop ◽  
Closed Loop Control ◽  
Loop Control ◽  
Inspection Robot ◽  
Industrial Age ◽  
Set Up ◽  
Close Loop Control

[abstFig src='/00280002/09.jpg' width=""300"" text='ASTERISK use our proposed method to walk' ]Since the industrial age began, increasing numbers of manufacturing plants have been set up to serve economic growth demand. More bridges were built simultaneously to connect cities and to make transportation more convenient. As these facilities have aged, regular maintenance has increased. The limb mechanism project we started almost 20 years ago was to deliver new types of inspection and maintenance to industrial fields. Our first prototype, a six-limb robot called Asterisk, included such capabilities as walking on ceilings, climbing and descending stairs and ladders, walking tightropes, and transversing rough terrain. Asterisk's latest version uses electromagnets to work in antigravity environments such as steel structures. Unfortunately, this presented a major danger, requiring that we replace electromagnets with electropermanent magnets (EPMs). Limitations on EPMs, however, required a new control strategy. We propose and compare three control methods -- open-loop control, closed-loop control using torque feedback, and closed-loop control using angle feedback -- in the sections that follow. Our objective is to determine the best control for inspection robots having electropermanent magnets but not using additional sensors.

scholarly journals Analysis of Dynamic Characteristics of a 600 kW Storage Type Wind Turbine with Hybrid Hydraulic Transmission

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 397 ◽  
Author(s):  
Zengguang Liu ◽  
Yanhua Tao ◽  
Liejiang Wei ◽  
Peng Zhan ◽  
Daling Yue
Keyword(s):  
Power Generation ◽  
Energy Storage ◽  
Wind Energy ◽  
Wind Turbine ◽  
Closed Loop ◽  
Control Method ◽  
Open Loop ◽  
Wheel Speed ◽  
Loop Control ◽  
Storage Type

In order to improve the efficiency and convenience of wind energy storage and solve the reproducibility of the hydraulic wind turbine, we present a storage type wind turbine with an innovative hybrid hydraulic transmission, which was adopted in the development of a 600 kW storage type wind turbine experimental platform. The whole hydraulic system of the storage type wind turbine is mainly an ingenious combination of a closed loop transmission and an open loop one, which can also be divided into three parts: hydraulic variable speed, hydraulic energy storage, power generation. For the study focusing on the capture and storage of wind energy, the mathematical model of the wind turbine except for the power generation was established under MATLAB/Simulink. A double closed loop control strategy is proposed to achieve the wind wheel speed regulation and wind energy storage. The dynamic simulations of the 600 kW storage type wind turbine experimental prototype were carried out under two different input signals. The results show that the wind wheel speed achieves the desired value at fast response and high precision using the control method given in this paper, and the proposed new storage type wind turbine is reasonable and practical.

Enhancement of dynamic performance of wave energy converter by introducing a flow control

2022 ◽  
pp. 014233122110699
Author(s):  
Dazhou Geng ◽  
Qijuan Chen ◽  
Yang Zheng ◽  
Xuhui Yue ◽  
Donglin Yan
Keyword(s):  
Flow Control ◽  
Transient Process ◽  
Closed Loop ◽  
Control Method ◽  
Control Valve ◽  
Open Loop ◽  
Closed Loop Control ◽  
Flow Control Valve ◽  
Open Loop Control ◽  
Loop Control

The stabilization of power take-off (PTO) is imperative especially under circumstances of fluctuating input wave energy. In this paper, a flow control valve is introduced to optimize the transient process of the hydraulic PTO, which can contribute to a quicker adjustment and a stronger stability. Under variations of input power and load torque in transient process, an open-loop control method and a closed-loop control method are proposed as the opening law of the above valve, and the hydraulic motor speed, the pressure at the accumulator inlet and the generated power are chosen as indicators to examine the regulation performance. Then, the synergic effect of the flow control valve and the accumulator in the transient process is discussed. The effectiveness of the two presented control methods on the fluctuation suppression is respectively tested and compared in both regular wave and irregular wave situations via simulation. To validate the practical effectiveness of the proposed methods, field experiments are conducted. The results demonstrate that the open-loop control can only improve the damping ability of the hydraulic PTO in the speed raising stage, while the closed-loop control can improve the stability both in the speed raising stage and in the load increasing stage.

scholarly journals Modelling And Control Of Automated Polishing/Deburring Process

2021 ◽  
Author(s):  
Liang Liao
Keyword(s):  
Feedback Linearization ◽  
Closed Loop ◽  
Control Method ◽  
Minimum Degree ◽  
Open Loop ◽  
Pole Placement ◽  
Control Performance ◽  
Nonlinear Controller ◽  
Loop Control ◽  
And Control

In this thesis, a new approach is presented for the modelling and control of an automated polishing/deburring process that utilizes a dual-purpose complaint toolhead mounted on a parallel tripod robot. This toolhead has a pneumatic spindle that can be extended and retracted by three pneumatic actuators to provide tool compliance. By integrating a pressure sensor and a linear encoder, this toolhead can be used for polishing and deburring. For the polishing open-loop control, the desired tool pressure is pre-planned based on the given part geometry. To improve control performance, a closed-loop controller is applied for pressure tracking through pressure sensing. For the deburring control, another closed-loop controller is applied to regulate the tool length through tool extension sensing. The two control methods have been tested and implemented on a polishing/deburring robot, and the experiment results demonstrate the effectiveness of the presented methods. To future improve the control performance, an adaptive controller is developed to deal with the uncertainties in the compliant tool. This control method combines the adaptive control theory with the constant stress theory of the contact model. A recursive last squares (RLS) estimator is developed to estimate the pneumatic plant model, and then a minimum-degree pole placement (MDPP) is applied to design a self-tuning controller. Afterwards, the simulation and experiment results of the proposed controller are presented and discussed. Finally, a nonlinear model of the pneumatic plant is developed. The nonlinear controller developed by using feedback linearization method is applied on the nonlinear pneumatic system of the compliant toolhead. The simulation is carried out to test the effectiveness of the pressure tracking for the polishing process.

scholarly journals Modelling And Control Of Automated Polishing/Deburring Process

2021 ◽  
Author(s):  
Liang Liao
Keyword(s):  
Feedback Linearization ◽  
Closed Loop ◽  
Control Method ◽  
Minimum Degree ◽  
Open Loop ◽  
Pole Placement ◽  
Control Performance ◽  
Nonlinear Controller ◽  
Loop Control ◽  
And Control

In this thesis, a new approach is presented for the modelling and control of an automated polishing/deburring process that utilizes a dual-purpose complaint toolhead mounted on a parallel tripod robot. This toolhead has a pneumatic spindle that can be extended and retracted by three pneumatic actuators to provide tool compliance. By integrating a pressure sensor and a linear encoder, this toolhead can be used for polishing and deburring. For the polishing open-loop control, the desired tool pressure is pre-planned based on the given part geometry. To improve control performance, a closed-loop controller is applied for pressure tracking through pressure sensing. For the deburring control, another closed-loop controller is applied to regulate the tool length through tool extension sensing. The two control methods have been tested and implemented on a polishing/deburring robot, and the experiment results demonstrate the effectiveness of the presented methods. To future improve the control performance, an adaptive controller is developed to deal with the uncertainties in the compliant tool. This control method combines the adaptive control theory with the constant stress theory of the contact model. A recursive last squares (RLS) estimator is developed to estimate the pneumatic plant model, and then a minimum-degree pole placement (MDPP) is applied to design a self-tuning controller. Afterwards, the simulation and experiment results of the proposed controller are presented and discussed. Finally, a nonlinear model of the pneumatic plant is developed. The nonlinear controller developed by using feedback linearization method is applied on the nonlinear pneumatic system of the compliant toolhead. The simulation is carried out to test the effectiveness of the pressure tracking for the polishing process.

Active Control of Combustion Instability Using Symmetric and Asymmetric Premix Fuel Modulation

2007 ◽  
Author(s):  
Daniel Guyot ◽  
Christian Oliver Paschereit
Keyword(s):  
Heat Release ◽  
Closed Loop ◽  
Modulation Frequency ◽  
Combustion Instability ◽  
Open Loop ◽  
Closed Loop Control ◽  
Nox Emissions ◽  
Loop Control ◽  
Asymmetric Modulation ◽  
Control Schemes

Active instability control was applied to an atmospheric swirl-stabilized premixed combustor using open loop and closed loop control schemes. Actuation was realised by two on-off valves allowing for symmetric and asymmetric modulation of the premix fuel flow while maintaining constant time averaged overall fuel mass flow. Pressure and heat release fluctuations in the combustor as well as NOx, CO and CO2 emissions in the exhaust were recorded. In the open loop circuit the heat release response of the flame was first investigated during stable combustion. For symmetric fuel modulation the dominant frequency in the heat release response was the modulation frequency, while for asymmetric modulation it was its first harmonic. In stable open loop control a reduction of NOx emissions due to fuel modulation of up to 19% was recorded. In the closed loop mode phase-shift control was applied while triggering the valves at the dominant oscillation frequency as well as at its second subharmonic. Both, open and closed loop control schemes were able to successfully control a low-frequency combustion instability, while showing only a small increase in NOx emissions compared to, for example, secondary fuel modulation. Using premixed open loop fuel modulation, attenuation was best when modulating the fuel at frequencies different from the dominant instability frequency and its subharmonic. The performance of asymmetric fuel modulation was generally slightly better than for symmetric modulation in terms of suppression levels as well as emissions. Suppression of the instability’s pressure rms level of up to 15.7 dB was recorded.

Design and control of 2-DoF joystick using MR-fluid rotary actuator

2021 ◽  
pp. 1045389X2110639
Author(s):  
Bao Tri Diep ◽  
Quoc Hung Nguyen ◽  
Thanh Danh Le
Keyword(s):  
Pid Controller ◽  
Force Feedback ◽  
Control Method ◽  
Open Loop ◽  
Friction Torque ◽  
Feedback Controls ◽  
Loop Control ◽  
Fuzzy Logic Algorithm ◽  
Experimental Apparatus ◽  
Close Loop Control

The purpose of this paper is to design a control algorithm for a 2-DoF rotary joystick model. Firstly, the structure of the joystick, which composes of two magneto-rheological fluid actuators (shorten MRFA) with optimal configuration coupled perpendicularly by the gimbal mechanism to generate the friction torque for each independent rotary movement, is introduced. The control strategy of the designed joystick is then suggested. Really, because of two independent rotary movements, it is necessary to design two corresponding controllers. Due to hysteresis and nonlinear dynamic characteristics of the MRFA, controllers based an accurate dynamic model are difficult to realize. Hence, to release this issue, the proposed controller (named self-turning fuzzy controllers-STFC) will be built through the fuzzy logic algorithm in which the parameters of controllers are learned and trained online by Levenberg-Marquardt training algorithm. Finally, an experimental apparatus will be constructed to assess the effectiveness of the force feedback controls. Herein, three experimental cases are performed to compare the control performance of open-loop and close-loop control method, where the former is done through relationship between the force at the knob and the current supplied to coil while the latter is realized based on the proposed controller and PID controller. The experimental results provide strongly the ability of the proposed controller, meaning that the STFC is robust and tracks well the desirable force with high accuracy compared with both the PID controller and the open-loop control method.

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