7,589 research outputs found
Micro-peat as a potential low-cost adsorbent material for COD and NH3-N removal
Micro-peat (M-P) was demonstrated in the present study as a potential low cost natural adsorbent for the removal of COD and ammoniacal nitrogen (NH3-N) from landfill leachate. A series of batch experiments were carried out under fixed conditions and the influence of mixture ratio was investigated. The characteristics of leachate were then determined. Results indicated that leachate is non-biodegradable with high concentration of COD (2739.06 mg/L), NH3-N (1765.34 mg/L) and BOD5/COD ratio (0.09). The optimum ratio for activated carbon (AC) and M-P in the removal of COD and NH3-N obtained were at 2.5:1.5 (87%) and 1.0:3.0 (65%) respectively. The low-cost natural adsorbent used in the present investigation is an attractive alternative to the conventional adsorbent (AC). Thus, M-P can be appropriated for use in leachate treatment that could be cost-effective due its local availability and adsorption property
Adaptive-smith predictor for controlling an automotive electronic throttle over network
The paper presents a control strategy for an automotive electronic throttle,
a device used to regulate the power produced by spark-ignition engines. Controlling
the electronic throttle body is a difficult task because the throttle accounts strong
nonlinearities. The difficulty increases when the control works through communication
networks subject to random delay. In this paper, we revisit the Smith-predictor
control, and show how to adapt it for controlling the electronic throttle body over a
delay-driven network. Experiments were carried out in a laboratory, and the corresponding
data indicate the benefits of our approach for applications.Peer ReviewedPostprint (published version
Development of c-means Clustering Based Adaptive Fuzzy Controller for A Flapping Wing Micro Air Vehicle
Advanced and accurate modelling of a Flapping Wing Micro Air Vehicle (FW MAV)
and its control is one of the recent research topics related to the field of
autonomous Unmanned Aerial Vehicles (UAVs). In this work, a four wing
Natureinspired (NI) FW MAV is modeled and controlled inspiring by its advanced
features like quick flight, vertical take-off and landing, hovering, and fast
turn, and enhanced manoeuvrability when contrasted with comparable-sized fixed
and rotary wing UAVs. The Fuzzy C-Means (FCM) clustering algorithm is utilized
to demonstrate the NIFW MAV model, which has points of interest over first
principle based modelling since it does not depend on the system dynamics,
rather based on data and can incorporate various uncertainties like sensor
error. The same clustering strategy is used to develop an adaptive fuzzy
controller. The controller is then utilized to control the altitude of the NIFW
MAV, that can adapt with environmental disturbances by tuning the antecedent
and consequent parameters of the fuzzy system.Comment: this paper is currently under review in Journal of Artificial
Intelligence and Soft Computing Researc
Vibration suppression in multi-body systems by means of disturbance filter design methods
This paper addresses the problem of interaction in mechanical multi-body systems and shows that subsystem interaction can be considerably minimized while increasing performance if an efficient disturbance model is used. In order to illustrate the advantage of the proposed intelligent disturbance filter, two linear model based techniques are considered: IMC and the model based predictive (MPC) approach. As an illustrative example, multivariable mass-spring-damper and quarter car systems are presented. An adaptation mechanism is introduced to account for linear parameter varying LPV conditions. In this paper we show that, even if the IMC control strategy was not designed for MIMO systems, if a proper filter is used, IMC can successfully deal with disturbance rejection in a multivariable system, and the results obtained are comparable with those obtained by a MIMO predictive control approach. The results suggest that both methods perform equally well, with similar numerical complexity and implementation effort
MIMO PID Controller Tuning Method for Quadrotor Based on LQR/LQG Theory
In this work, a new pre-tuning multivariable PID (Proportional Integral Derivative)
controllers method for quadrotors is put forward. A procedure based on LQR/LQG (Linear Quadratic
Regulator/Gaussian) theory is proposed for attitude and altitude control, which suposes a considerable
simplification of the design problem due to only one pretuning parameter being used. With the aim to
analyze the performance and robustness of the proposed method, a non-linear mathematical model of
the DJI-F450 quadrotor is employed, where rotors dynamics, together with sensors drift/bias properties
and noise characteristics of low-cost commercial sensors typically used in this type of applications are
considered. In order to estimate the state vector and compensate bias/drift effects in the measures,
a combination of filtering and data fusion algorithms (Kalman filter and Madgwick algorithm for attitude
estimation) are proposed and implemented. Performance and robustness analysis of the control system
is carried out by employing numerical simulations, which take into account the presence of uncertainty
in the plant model and external disturbances. The obtained results show the proposed controller design
method for multivariable PID controller is robust with respect to: (a) parametric uncertainty in the plant
model, (b) disturbances acting at the plant input, (c) sensors measurement and estimation errors
A simulation of the instrument pointing system for the Astro-1 mission
NASA has recently completed a shuttle-borne stellar ultraviolet astronomy mission known as Astro-1. A three axis instrument pointing system (IPS) was employed to accurately point the science instruments. In order to analyze the pointing control system and verify pointing performance, a simulation of the IPS was developed using the multibody dynamics software TREETOPS. The TREETOPS IPS simulation is capable of accurately modeling the multibody IPS system undergoing large angle, nonlinear motion. The simulation is documented and example cases are presented demonstrating disturbance rejection, fine pointing operations, and multiple target pointing and slewing of the IPS
Neural-Network Vector Controller for Permanent-Magnet Synchronous Motor Drives: Simulated and Hardware-Validated Results
This paper focuses on current control in a permanentmagnet synchronous motor (PMSM). The paper has two main objectives: The first objective is to develop a neural-network (NN) vector controller to overcome the decoupling inaccuracy problem associated with conventional PI-based vector-control methods. The NN is developed using the full dynamic equation of a PMSM, and trained to implement optimal control based on approximate dynamic programming. The second objective is to evaluate the robust and adaptive performance of the NN controller against that of the conventional standard vector controller under motor parameter variation and dynamic control conditions by (a) simulating the behavior of a PMSM typically used in realistic electric vehicle applications and (b) building an experimental system for hardware validation as well as combined hardware and simulation evaluation. The results demonstrate that the NN controller outperforms conventional vector controllers in both simulation and hardware implementation
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