336 research outputs found
CAD enabled trajectory optimization and accurate motion control for repetitive tasks
As machine users generally only define the start
and end point of the movement, a large trajectory optimization potential rises for single axis mechanisms performing repetitive tasks. However, a descriptive mathematical model of the mecha- nism needs to be defined in order to apply existing optimization techniques. This is usually done with complex methods like virtual work or Lagrange equations. In this paper, a generic technique is presented to optimize the design of point-to-point trajectories by extracting position dependent properties with CAD motion simulations. The optimization problem is solved by a genetic algorithm. Nevertheless, the potential savings will only be achieved if the machine is capable of accurately following the optimized trajectory. Therefore, a feedforward motion controller is derived from the generic model allowing to use the controller for various settings and position profiles. Moreover, the theoretical savings are compared with experimental data from a physical set-up. The results quantitatively show that the savings potential is effectively achieved thanks to advanced torque feedforward with a reduction of the maximum torque by 12.6% compared with a standard 1/3-profil
Catalytic thermal degradation of Chlorella Vulgaris: Evolving deep neural networks for optimization
The aim of this study is to identify the optimum thermal conversion of Chlorella vulgaris with neuro-evolutionary approach. A Progressive Depth Swarm-Evolution (PDSE) neuro-evolutionary approach is proposed to model the Thermogravimetric analysis (TGA) data of catalytic thermal degradation of Chlorella vulgaris. Results showed that the proposed method can generate predictions which are more accurate compared to other conventional approaches (>90% lower in Root Mean Square Error (RMSE) and Mean Bias Error (MBE)). In addition, Simulated Annealing is proposed to determine the optimal operating conditions for microalgae conversion from multiple trained ANN. The predicted optimum conditions were reaction temperature of 900.0 °C, heating rate of 5.0 °C/min with the presence of HZSM-5 zeolite catalyst to obtain 88.3% of Chlorella vulgaris conversion
Catalytic thermal degradation of Chlorella Vulgaris: Evolving deep neural networks for optimization
The aim of this study is to identify the optimum thermal conversion of Chlorella vulgaris with neuro-evolutionary approach. A Progressive Depth Swarm-Evolution (PDSE) neuro-evolutionary approach is proposed to model the Thermogravimetric analysis (TGA) data of catalytic thermal degradation of Chlorella vulgaris. Results showed that the proposed method can generate predictions which are more accurate compared to other conventional approaches (>90% lower in Root Mean Square Error (RMSE) and Mean Bias Error (MBE)). In addition, Simulated Annealing is proposed to determine the optimal operating conditions for microalgae conversion from multiple trained ANN. The predicted optimum conditions were reaction temperature of 900.0 °C, heating rate of 5.0 °C/min with the presence of HZSM-5 zeolite catalyst to obtain 88.3% of Chlorella vulgaris conversion
Design and Simulation of a Neuroevolutionary Controller for a Quadcopter Drone
The problem addressed in the present paper is the design of a controller based on an evolutionary neural network for autonomous flight in quadrotor systems. The controller's objective is to govern the quadcopter in such a way that it reaches a specific position, bearing on attitude limitations during flight and upon reaching a target. Given the complex nature of quadcopters, an appropriate neural network architecture and a training algorithm were designed to guide a quadcopter toward a target. The designed controller was implemented as a single multi-layer perceptron. On the basis of the quadcopter's current state, the developed neurocontroller produces the correct rotor speed values, optimized in terms of both attitude-limitation compliance and speed. The neural network training was completed using a custom evolutionary algorithm whose design put particular emphasis on the cost function's definition. The developed neurocontroller was tested in simulation to drive a quadcopter to autonomously follow a complex path. The obtained simulated results show that the neurocontroller manages to effortlessly follow several types of paths with adequate precision while maintaining low travel times
Improving malware detection with neuroevolution : a study with the semantic learning machine
Project Work presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Knowledge Management and Business IntelligenceMachine learning has become more attractive over the years due to its remarkable adaptation and
problem-solving abilities. Algorithms compete amongst each other to claim the best possible results
for every problem, being one of the most valued characteristics their generalization ability.
A recently proposed methodology of Genetic Programming (GP), called Geometric Semantic Genetic
Programming (GSGP), has seen its popularity rise over the last few years, achieving great results
compared to other state-of-the-art algorithms, due to its remarkable feature of inducing a fitness
landscape with no local optima solutions. To any supervised learning problem, where a metric is used
as an error function, GSGP’s landscape will be unimodal, therefore allowing for genetic algorithms to
behave much more efficiently and effectively.
Inspired by GSGP’s features, Gonçalves developed a new mutation operator to be applied to the Neural
Networks (NN) domain, creating the Semantic Learning Machine (SLM). Despite GSGP’s good results
already proven, there are still research opportunities for improvement, that need to be performed to
empirically prove GSGP as a state-of-the-art framework.
In this case, the study focused on applying SLM to NNs with multiple hidden layers and compare its
outputs to a very popular algorithm, Multilayer Perceptron (MLP), on a considerably large classification
dataset about Android malware. Findings proved that SLM, sharing common parametrization with
MLP, in order to have a fair comparison, is able to outperform it, with statistical significance
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