The paper addresses several control problems for a three-dimensional hopping machine. The machine consists of a ponderable torso and an imponderable leg. The leg is a kinematic chain with joints allowing rotation and ...
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The paper addresses several control problems for a three-dimensional hopping machine. The machine consists of a ponderable torso and an imponderable leg. The leg is a kinematic chain with joints allowing rotation and translation. The leg is attached at the torso's center of mass. The force in the leg is developed by a linear spring. A control system is synthesized within the framework of a periodic linear quadratic problem. The efficiency of the controller is exemplified by a case where the hopper changes the direction of its motion.
A genetic algorithm was used to optimize performance of a fuzzy inference system acting as a controller for a magnetically actuated CubeSat. A solely magnetically controlled satellite is a nonlinear, underactuated sys...
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A genetic algorithm was used to optimize performance of a fuzzy inference system acting as a controller for a magnetically actuated CubeSat. A solely magnetically controlled satellite is a nonlinear, underactuated system for which the uncontrollable axis varies as a function of orbit position and attitude;variation is approximately periodic with orbit position. Therefore, controllability is not guaranteed, making solely magnetic control a less than ideal option for spacecraft requiring a high degree of pointing accuracy or spacecraft subject to relatively large disturbances. However, for small spacecraft, such as CubeSats, with modest pointing and disturbance rejection requirements, solely magnetic actuation is a good option. The genetic-algorithm-tuned fuzzy controller solution was compared to a similar linear quadratic regulator solution that was tuned to minimize the cost function used by the genetic algorithm. Both were optimized with respect to a single set of initial conditions. The genetic-algorithm-tuned fuzzy controller was found to be a lower-cost solution than the linear quadratic regulator for the optimized set of initial conditions. Additionally, a MonteCarlo analysis showed the genetic-algorithm-tuned fuzzy controller tended to settle faster than the linear quadratic regulator over a variety of initial conditions.
As the clinical application of LVADs has increased, attempts have been made to develop smaller, less expensive, more durable and efficient implantable devices using rotary blood pumps. Since chronic circulatory suppor...
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As the clinical application of LVADs has increased, attempts have been made to develop smaller, less expensive, more durable and efficient implantable devices using rotary blood pumps. Since chronic circulatory support with implantable continuous-flow LVADs will be established in the near future, we need to determine the flow characteristics through an implantable continuous-flow LVAD. This study describes the flow characteristics through an implantable centrifugal blood pump as a left ventricular assist device (LVAD) to obtain a simple non-invasive algorithm to control its assist flow rate adequately. A prototype of the completely seal-less and pivot bearing-supported centrifugal blood pump was implanted into two calves, bypassing from the left ventricle to the descending aorta. Device motor speed, voltage, current, flow rate, and aortic blood pressure were monitored continuously. The how patterns revealed forward how in ventricular systole and backward flow in diastole. As the pump speed increased, an end-diastolic notch became evident in the flow profile. Although the flow rate (Q [l/min]) and rotational speed (R [rpm]) had a linear correlation (Q = 0.0042R - 5.159;r = 0.96), this linearity was altered after the end-diastolic notch was evident. The end-diastolic notch is considered to be a sign of the sucking phenomenon of the centrifugal pump. Also, although the consumed current (I [A]) and how rate had a linear correlation (I = 0.212Q + 0.29;r = 0.97), this linearity also changed after the end-diastolic notch was evident. Based upon the above findings, we propose a simple algorithm to maintain submaximal flow without inducing sucking. To maintain the submaximal flow rate without measuring flow rate, the sucking point is determined by monitoring consumed current according to gradual increases in voltage.
The objective of this study is to investigate the possibility of the application of a time domain learning algorithm for controlling a tab mounted at the trailing edge of a blade to diminish the rotor vibration level....
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The objective of this study is to investigate the possibility of the application of a time domain learning algorithm for controlling a tab mounted at the trailing edge of a blade to diminish the rotor vibration level. The learning control algorithm has been modified and applied to the nonlinear periodic system that models a helicopter rotor blade. The numerical simulations show that, with an appropriate tab length and selected control constant, the blade twist angle can be influenced in such a way that the blade follows the required motion. A somewhat impractical tab spanwise length is needed to fulfill this task, suggesting that mass and stiffness tailoring of the blade should be a necessary follow-up exercise to obtain effective control within acceptable design parameters. (AIAA)
We introduce particle swarm optimization (PSO) into adaptive polarization-mode dispersion (PMD) compensation in a 40-Gb/s optical time-division-multiplexing communication system. In the searching process for automatic...
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We introduce particle swarm optimization (PSO) into adaptive polarization-mode dispersion (PMD) compensation in a 40-Gb/s optical time-division-multiplexing communication system. In the searching process for automatic PMD compensation, the PSO algorithm has the merits of rapid convergence to the global optimum, without being trapped in local suboptima, and good robustness to noise. In this letter, we describe how to implement PSO as a component of a control algorithm in adaptive PMD compensation. Performance comparisons between global and local versions of PSO were carried out theoretically and experimentally. We also demonstrate that a time-varying PMD can be successfully tracked using the PSO technique.
In biped walking, dynamic balance ability is an important evaluation index. Zero-moment-point-based trajectory control is a common method for biped dynamic walking, but it requires complex control mechanisms that limi...
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In biped walking, dynamic balance ability is an important evaluation index. Zero-moment-point-based trajectory control is a common method for biped dynamic walking, but it requires complex control mechanisms that limit its applications. With the help of passive dynamics, the biped walking based on the inverted pendulum model can achieve dynamic walking in a simple way;however, it has no stopping ability, which is necessary for practical use. To solve this problem, this article proposes a footed inverted pendulum model and develops a simple three-part decomposition control algorithm for controlling biped dynamic walking based on the model. In the control algorithm, the biped walking is decomposed into three separate control parts: body posture, body height, and body velocity. Body posture is controlled by the stance hip, body height is controlled by the stance knee, and body velocity is controlled by the stance ankle and swing foot placement simultaneously. A simulation is presented to analyze the foot's effect on the inverted pendulum model. Two hardware experiments exploring velocity control and balance are described, with the results showing that the biped can achieve dynamic walking with stopping ability by using the simple control algorithm based on the footed inverted pendulum model.
Purpose: A control algorithm for radio-frequency-induced intestinal tissue fusion was developed to explore the effects of different control parameters on intestinal tissue fusion. Materials and methods: Radio-frequenc...
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Purpose: A control algorithm for radio-frequency-induced intestinal tissue fusion was developed to explore the effects of different control parameters on intestinal tissue fusion. Materials and methods: Radio-frequency-induced fusion was performed on ex vivo small intestine tissue. The effect on the fusion was observed by changing the control parameters (power, interval time, and terminal impedance) in the algorithm. The quality of fusion was evaluated using the burst pressure and thermal damage measurement. Histological evaluation was used to assess the fusion quality indirectly. Results: A maximum burst pressure of 8.460 +/- 0.2674 KPa was acquired when the power was set to 100 W, the interval time was set to 2000 ms, and the terminal impedance was set to 50 omega. Moreover, the thermal damage range increased with an increase in power but decreased with an increase in the interval time and terminal impedance. Furthermore, the thermal damage range and temperature were presumably related. Conclusions: For an ex vivo small intestine tissue, the appropriate control parameters could be set when the power was approximately 100 W, the interval time was approximately 2000 ms, and the terminal impedance was approximately 50 omega. This study could provide a basis for the selection of control parameters for intestinal tissue fusion.
Considering that the current cost control algorithm has the problems of poor control effect and high cost of manpower and material resources in enterprise cost control, a target cost control algorithm based on Hypercy...
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Considering that the current cost control algorithm has the problems of poor control effect and high cost of manpower and material resources in enterprise cost control, a target cost control algorithm based on Hypercycle model is proposed. By analyzing the relationship between capital, price, technology and target cost control, this paper analyzes the influence of uncertain factors on target cost, and constructs a cost control super cycle model to realize enterprise cost control. Examples show that the algorithm can effectively improve the cost effect of enterprises, and has the practicability of reducing enterprise costs and improving enterprise profits.
There are several algorithms for determining control forces of active devices in civil engineering structures. Uniform distribution of deformations theory is a structural concept which mainly focuses on equalizing def...
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There are several algorithms for determining control forces of active devices in civil engineering structures. Uniform distribution of deformations theory is a structural concept which mainly focuses on equalizing deformations in order to promote the utilization of ductility capacity of structural elements thereby mitigating damages to a structure. In common active control algorithms, deformation uniformity and reducing damages are barely noted. In this research, a new active control algorithm regarding uniform deformation theory will be proposed. Uniform distribution of Deformation control (UDC) algorithm consists of a massless optimized Virtual Added linear structure with Pinned connections (VAP) which is added to a desired original structure. This VAP can be treated as an added stiffness matrix. Once the parameters of the VAP were optimized in a manner that the desired responses were obtained from the new integrated structure, then, the new integrated structure is developed and analyzed in each time step. Finally, the VAP beams axial forces are extracted and applied to the original structure as control forces via active control devices such as active tendons. This proposed control algorithm is simple and effective in reducing responses especially drifts, making more uniform thereby reducing structural damages as well as decreasing the required capacity of actuators and the power consumption eventually. High potential and promising performance of the proposed UDC algorithm will be represented through numerical investigation in an office building example. The results are compared with Nonlinear Instantaneous Optimal control (NIOC) algorithm as a very common active control algorithm for linear and nonlinear structures.
When the state of the robot reaches the smooth sliding plane, the current algorithm will generate high-frequency chattering, resulting in larger tracking error and longer response time. To solve these problems, we hav...
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When the state of the robot reaches the smooth sliding plane, the current algorithm will generate high-frequency chattering, resulting in larger tracking error and longer response time. To solve these problems, we have proposed a trajectory tracking and control algorithm based on exponential reaching rate. The coordinate system of parallel robot system is established, and the kinetic energy and potential energy of the system are calculated. The results are brought into the Lagarnge equation to find the dynamic model of the system. The power amplifier, electro-hydraulic servo valve, hydraulic cylinder and its load are taken as generalized controlled objects, and the hydraulic servo system model is established. The exponential approaching rate is introduced to design the dynamics model and the trajectory tracking sliding controller of the hydraulic servo system model. By adjusting the upper and lower bounds of the external disturbance of the controller, the control rate is changed, the buffeting occurrence is reduced, and the response time is shortened, to realize the low error tracking of any trajectory of the robot. The experimental results show that the trajectory of the robot can be adjusted quickly and the desired trajectory is better tracked by the end.
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