Buoyancy Control for Low-Speed Under-Actuated AUVs

2014 ◽  
Vol 644-650 ◽  
pp. 735-740
Author(s):  
Yu Ling Ye
Keyword(s):  
Real Time ◽  
Control Algorithm ◽  
Sea Water ◽  
Water Tank ◽  
Low Speed ◽  
The Real ◽  
Control Approach ◽  
Control Scheme ◽  
Control Devices ◽  
Buoyancy Control

An engineering buoyancy control scheme was proposed to compensate the change of residual buoyancy for low-speed under-actuated AUVs. The buoyancy control system is made up of buoyancy controller and two sets of buoyancy control devices include: water tank, sea water pump, valve grouping, pipeline etc. Buoyancy control devices were configured to both head and tail part of the AUV symmetrical to its buoyant center. Depth control algorithm and buoyancy control algorithm were proposed separately. In the process of voyage at a constant depth, the real time speed, pitch angle and depth error were detected to evaluate the residual buoyancy indirectly, and then the real time buoyancy control was executed by pumping the water into or out of the tanks. The buoyancy control scheme was applied to the type of low-speed under-actuated AUV and simulation and experiments results show that the buoyancy control approach and the control laws are feasible and effective.

Research on Accurate Modeling and Control for Pneumatic Electric Braking System of Commercial Vehicle Based on Multi-Dynamic Parameters Measurement

2020 ◽  
Author(s):  
Yongtao Zhao ◽  
Yiyong Yang ◽  
Xiuheng Wu ◽  
Xingjun Tao
Keyword(s):  
Dynamic Response ◽  
Real Time ◽  
Predictive Control ◽  
Control Algorithm ◽  
Control Algorithms ◽  
Dynamic Parameters ◽  
Braking System ◽  
Control Scheme ◽  
Braking Force ◽  
Electric Braking

Abstract Accurate pressure control and fast dynamic response are vital to the pneumatic electric braking system (PEBS) for that commercial vehicles require higher regulation precision of braking force on four wheels when braking force distribution is carried out under some conditions. Due to the lagging information acquisition, most feedback-based control algorithms are difficult to further improve the dynamic response of PEBS. Meanwhile, feedforward-based control algorithms like predictive control perform well in improving dynamic performance. but because of the large amount of computation and complexity of this kind of control algorithm, it cannot be applied in real-time on single-chip microcomputer, and it is still in the stage of theoretical research at present. To address this issue and for the sake of engineering reliability, this article presents a logic threshold control scheme combining analogous model predictive control (AMPC) and proportional control. In addition, an experimental device for real-time measuring PEBS multi-dynamic parameters is built. After correcting the key parameters, the precise model is determined and the influence of switching solenoid valve on its dynamic response characteristics is studied. For the control scheme, numerical and physical validation are executed to demonstrate the feasibility of the strategy and for the performance of the controller design. The experimental results show that the dynamic model of PEBS can accurately reflect its pressure characteristics. Furthermore, under different air source pressures, the designed controller can stably control the pressure output of PEBS and ensure that the error is within 8KPa. Compared with the traditional control algorithm, the rapidity is improved by 32.5%.

Research of Paddle Wave-Maker Control System Based on Jonswap Spectrum

2014 ◽  
Vol 1006-1007 ◽  
pp. 679-684
Author(s):  
Xue Fei Huang ◽  
Mao Pang
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Energy Saving ◽  
Real Time ◽  
Personal Computer ◽  
Control Algorithm ◽  
Change Rate ◽  
The Real ◽  
Wave Maker ◽  
Jonswap Spectrum

According to large energy consumption, overload and re-reflection problemr, the control algorithm of wave-maker has been improved based on Jonswap spectrum. The control algorithm is comprised of the offline calculation of the control waveform and the real-time governing of the wave paddle. Offline algorithm is implemented on a personal computer, whereas paddle control is realized on a programmable automation controller. The experiments results show that the speed is continuous and stable, change rate of load has been optimized obviously and achieves the purpose of energy saving.

CONTROL OF CHAOS THROUGH AN INSTANTANEOUS LYAPUNOV EXPONENT TARGETING CONTROL ALGORITHM

2008 ◽  
Vol 18 (08) ◽  
pp. 2319-2344
Author(s):  
AHMED OTEAFY ◽  
MOHAMED ZRIBI ◽  
NEJIB SMAOUI
Keyword(s):  
Lyapunov Exponents ◽  
Chaotic Dynamics ◽  
Control Algorithm ◽  
Control Method ◽  
Chaotic Oscillator ◽  
Oscillator System ◽  
Control Approach ◽  
First Case ◽  
Control Scheme ◽  
The Lorenz System

This paper presents an approach to control the chaotic dynamics of discrete-time (or discretizable) systems. The objective of the paper is to focus on the suppression of the chaotic dynamics and the restoration of order with a state feedback controller. The proposed control method works by targeting instantaneous measures of the Lyapunov exponents of a system and setting them to desired values. At first, the paper presents an instantaneous measure of the Lyapunov exponents; this measure is used to control the system's dynamics. Then, the formulation of the control algorithm to suppress chaos is presented. Two cases for the control structure are considered. The first case corresponds to the case when the number of control inputs is equal to the number of states; the second case corresponds to the case when the number of control inputs is less than the number of states. The Lorenz system, the smooth Chua Oscillator system, the Rössler-hyperchaos system and a fourth order chaotic oscillator system are used as examples to illustrate the proposed control scheme. The simulation results show the efficacy of the proposed control approach.

Hovering Control Based on Buoyancy Control Approach for Under-Actuated AUVs

2014 ◽  
Vol 687-691 ◽  
pp. 402-406
Author(s):  
Bao Gen Liu ◽  
Yu Ling Ye
Keyword(s):  
Control System ◽  
Sea Water ◽  
Control Law ◽  
Control Approach ◽  
Depth Data ◽  
Pressure Water ◽  
Water Tanks ◽  
Hovering Control ◽  
Buoyancy Control

A buoyancy control system was presented to realize the powerless descent/ascent motion for an under-actuated AUV like REMUS. The sea water was injected into or drained out of the pressure water tanks to tunes the residual buoyancy of the vehicle, and the buoyancy control was realized. An engineering hovering control law based on buoyancy control approach was proposed to keep the vehicle hovering at the programmed depth. The injection and drainage instructs were worked out only based on depth data and its difference, so the hovering control system need not additional sensors. The simple and reliable hovering control system was applied to a type of huge under-actuated AUV, and the experiment results show that it is feasible.

scholarly journals Optimization of 3D controlled ELM-free state with recovered global confinement for tokamak fusion plasmas

2021 ◽  
Author(s):  
SangKyeun Kim ◽  
Ricardo Shousha ◽  
SangHee Hahn ◽  
Andrew Nelson ◽  
Josiah Wai ◽  
...  
Keyword(s):  
Real Time ◽  
Free State ◽  
Fusion Reactors ◽  
Fusion Plasmas ◽  
Real Time Control ◽  
The Real ◽  
Time Control ◽  
Control Scheme ◽  
Edge Localized Modes ◽  
Viable Approach

Abstract Mitigation of deleterious heat flux from edge-localized modes (ELMs) on fusion reactors is often attempted with 3D perturbations of the confining magnetic fields. However, the established technique of resonant magnetic perturbations (RMPs) also degrades plasma performance, complicating implementation on future fusion reactors. In this paper, we introduce an adaptive real-time control scheme as a viable approach to simultaneously achieve both ELM-free states and recovered high-confinement (βN~1.91$ and HN~0.9), demonstrating successful handling of a volatile complex system through adaptive measures. We show that, by exploiting a salient hysteresis process to adaptively minimize the RMP strength, stable ELM suppression can be achieved while actively encouraging confinement recovery. This is made possible by a self-organized transport response in the plasma edge which reinforces the confinement improvement through a widening of the ion pedestal and promotes control stability, in contrast to the deteriorating effect on performance observed in standard RMP experiments. These results establish the real-time approach as an up-and-coming solution towards an optimized ELM-free state, which is an important step for the operation of ITER and reactor-grade tokamak plasmas. Notably, the real-time adaptive control scheme introduced here provides a path towards economic fusion reactors by maximizing the fusion gain while minimizing damage to machine components.

Preemptive Control of Multiply Actuated Processes: Application to Moisture Content Control in Paper Manufacturing Using Surrogate Measurements

2001 ◽  
Author(s):  
Perry Y. Li ◽  
Petar J. Bjegovic ◽  
Shri Ramaswamy
Keyword(s):  
Moisture Content ◽  
Control Algorithm ◽  
Robustness Analysis ◽  
Manufacturing Processes ◽  
Simulation Studies ◽  
Energy Usage ◽  
Control Approach ◽  
Paper Manufacturing ◽  
Control Scheme ◽  
Vacuum Dewatering

Abstract Many manufacturing processes involve the successive processing of the substrate at multiple station on a transport medium, with the hope that at the end of the process, the product has the desired property. Paper manufacturing is an example in which over 90% of the water from pulp is sequentially removed through gravity, vacuum dewatering, pressing, and thermal drying. The consistency and uniformity of the moisture content at the end of process is important for paper quality. Current strategy for the control of moisture content uses a feedback sensor at the end of the process to adjust the dryers. This introduces a long deadtime and causes excessive use of the dryers, which translate to limitations in performance, robustness and inefficient energy usage. In this paper, we investigate a new control approach in which in-process moisture contents are estimated using air-flow as surrogate measurements, and the pressure settings in the multiple vacuum dewatering boxes are adjusted according to the surrogate measurements. A preemptive control algorithm is developed which has the ability to decouple and eliminate the effects of the disturbances that occur upstream in the process from downstream. Robustness analysis and simulation studies suggest that as long as the surrogate measurements are accurate, the proposed control scheme will be robust and accurate.

An enhanced computed-torque control algorithm for robot manipulators

1998 ◽  
Vol 212 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Q Li ◽  
S K Tso ◽  
A N Poo
Keyword(s):  
Control Algorithm ◽  
Internal Model Control ◽  
Torque Control ◽  
Simulation Studies ◽  
Control Approach ◽  
Computed Torque Control ◽  
Control Scheme ◽  
Model Control ◽  
Theoretical Analyses ◽  
Computed Torque

An enhanced computed-torque control approach, which is developed based on the intuitive design concept of the internal model control structure, is proposed in this paper. Both theoretical analyses and simulation studies on a two-link robot prove that the robustness of this enhanced algorithm can surpass that of the conventional computed-torque control scheme by a large extent.

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