Frederic Conrad Janzen

Position control of roboticmanipulator joints with twodegrees of free-domusing sdre control

This paper presents a control design for robotic manipulators with two links. The dynamic model of the manipulator is obtained in a closed form through the Lagrange equations. The control strategy involves the application of two control signals, a nonlinear feedforward control to maintain the controlled system in a desired point, and a state feedback control, obtained by the State Dependent Riccati Equation (SDRE), to bring the system trajectory into at a desired point. The control is realized through the control of motor voltage. A state-dependent equation is solved at each new point obtained for the variables from the problem, along the trajectory to obtain a nonlinear feedback controller. Numerical simulations demonstrate the effectiveness of the control strategy in leading the system from any initial condition to a desired point.

On an Optimal Control Applied in MEMS Oscillator with Chaotic Behavior including Fractional Order

The dynamical analysis and control of a nonlinear MEMS resonator system is considered. Phase diagram, power spectral density (FFT), bifurcation diagram, and the 0-1 test were applied to analyze the influence of the nonlinear stiffness term related to the dynamics of the system. In addition, the dynamical behavior of the system is considered in fractional order. Numerical results showed that the nonlinear stiffness parameter and the order of the fractional order were significant, indicating that the response can be either a chaotic or periodic behavior. In order to bring the system from a chaotic state to a periodic orbit, the optimal linear feedback control (OLFC) is considered. The robustness of the proposed control is tested by a sensitivity analysis to parametric uncertainties.

SDRE Control Applied to the Wheel Speed of a Compressed Air Engine with Crank-Connecting-Rod Mechanism

Renewable energy sources for vehicles have been the motivation of many researches around the world. The reduction of fossil fuels deposits and increase of the pollution in cities bring the need of more efficient and cleaner energy sources. In this way, this work will present the application of a compressed air engine applied to a bicycle. The engine is composed of two pneumatic cylinders connected to the bicycle wheel through a crank-connecting-rod mechanism. In order to control the velocity of the bicycle, a strategy of control composed of two controls was implemented: a feedback and a feedforward control. For feedback control, the State-Dependent Riccati Equation (SDRE) control and also a proportional-derivative (PD) control are considered, considering three cases for velocity bicycle variation: 10 km/h, 20 km/h, and 30 km/h. The equations of motion of the system were obtained through the Lagrangian energy method. Numerical simulations were performed in order to analyze the dynamics of the system and the efficiency of the controllers.

Optimal Control for Robot Manipulators with Three-Degress-of-Freedom

This work presents the modeling and simulation of a manipulator robot with three degrees of freedom and considering its structures with rigid behavior. The concepts of kinematics for the mathematical deduction and the Lagrangian mechanics were used to obtain the dynamic models of the manipulator and the DC actuators with permanent magnet. Due to nonlinearity and dynamics characteristics, both the states observer and the control used were based on State Dependet Ricatti Equation (SDRE). The simulations made for constant performance parameters demonstrated the effectiveness of the optimal control applied to the manipulator and to the chosen DC actuator models. The applications of trajectories to the manipulator enrich the applicability of the project and the results obtained with the techniques chosen show his efficiency.

Nonlinear control strategy based on discrete-time state dependent riccati equation for electronic throttle control

This paper aims to present a new control strategy for eletronic throttle control (ETC) used for the acceleration function in a vehicle. Firstly, an analitical model describing is developed with the purpose to evaluation the dynamic behaviour of ETC. The ETC is a non-linear system which the traditional control strategies cannot provide a great control performance. Thus, based on the discret-time state dependent riccati equation (D-SDRE) that has been successfull for the control of non-linear physical plants, we present the application of this control strategy for the ETC. Numerical simulations are done with the purpose to demonstrate a better performance and motivational application of our approach.

Position Control of a Manipulator Robotic Arm Considering Flexible Joints Driven by a DC Motor and a Controlled Torque by a MR-Brake

This paper presents a two-degree-of-freedom robotic arm design with flexible joints driven by a DC Motor and controlled by a Magnetorheological (MR) Brake, considering a feedback control. The MR Brake is used to provide adjustable constraints in motion of the manipulator and compensate overshoot by interactions between the robot’s links and flexible joints of the motor drive mechanism. The torque of the MR Brake is obtained by the Radial Basis Function Neural Networks (RBFNN), which is a widely used class of neural networks for prediction or approximation of function. The RBFNN provides the nonlinear curve of hysteresis of MR brake to use torque. Two controllers were proposed to control the manipulator. The first one is obtained by feedback linearization control with the objective to remove the non-dependent terms of the state space equation. The second one is the feedback control obtained using the State-Dependent Riccati Equation (SDRE) with the objective of controlling the position of the manipulator and the torque applied on the MR brake. The numerical simulation results showed that the proposed control using both signal feedback linearization control and a feedback control signal by a DC Motor and MR Brake is effective to control the flexible joint manipulators.Copyright

AVALIAÇÃO FLUIDODINÂMICA DA SECAGEM DE SUSPENSÃO DILUIDA EM LEITO FLUIDIZADO UTILIZANDO ANÁLISE ESPECTRAL GAUSSIANA

O presente trabalho consiste em avaliar as transições de regime de fluidização durante o processo de secagem de suspensão diluída utilizando a análise espectral Gaussiana, que se baseia na medição das flutuações de pressão no leito. Os ensaios experimentais foram realizados em escala laboratorial composto por uma coluna de acrílico de 0,11 m de diâmetro interno e 1,0 m de altura. O equipamento experimental foi instrumentado com transdutores de pressão de resposta rápida, termopares e termohigrômetros acoplados a um sistema de aquisição e processamento de sinais, composto por uma placa de aquisição de dados, um microcomputador e pelo software LabView 10.0. Esferas de alumínio com diâmetro médio de partícula de 1,55 mm foram usadas como material inerte, e suspensão de carbonato de cálcio com concentração de 9%, em massa, foi utilizada como material pastoso pulverizado sobre o leito. A vazão de atomização da suspensão foi de 12 e 15 mL/min. Os resultados mostraram que a transição dos regimes de fluidização durante o processo de secagem de suspensão aquosa pode ser monitorada com a técnica da análise espectral Gaussiana.

SDRE control strategy applied to a nonlinear robotic including drive motor

A robotic control design considering all the inherent nonlinearities of the robot-engine configuration is developed. The interactions between the robot and joint motor drive mechanism are considered. The proposed control combines two strategies, one feedforward control in order to maintain the system in the desired coordinate, and feedback control system to take the system into a desired coordinate. The feedback control is obtained using State-Dependent Riccati Equation (SDRE). For link positioning two cases are considered. Case I: For control positioning, it is only used motor voltage; Case II: For control positioning, it is used both motor voltage and torque between the links. Simulation results, including parametric uncertainties in control shows the feasibility of the proposed control for the considered system.

Suppression of chaotic vibrations in a nonlinear half-car model

The present work investigates the nonlinear response of a half-car model. The disturbances of the road are assumed to be sinusoidal. After constructing the bifurcation diagram, we using the 0-1 test for identify the chaotic motion. The principal objective of this study is to eliminate the chaotic behaviour of the chassis and reduce its vibration, and for this reason a control system for semi-active vehicle suspension with magnetorheological damper is proposed. The control mechanism is designed based on SDRE technique, where the control parameter is the voltage applied to the coil of the damper. Numerical results show that the proposed control method is effective in significantly reducing of the chassis vibration, increasing therefore, passenger comfort.

Peak Detection Algorithm for Fiber Bragg grating Sensors

Fiber Bragg gratings (FBGs) are widely studied because of their properties to measure variables like temperature, strain, pressure among others. This work proposes a simple and efficient FBG peak detection algorithm.