Vibration Reduction of a Vision-Based Controlled Flexible Arm: Theoretical and Experimental Aspects

2005 ◽  
Author(s):  
Shuxin Wang ◽  
Bingquan Wen ◽  
Hongbo Yu ◽  
Jintian Yun
Keyword(s):  
Dynamic Models ◽  
Controller Design ◽  
Model Simulation ◽  
Sampling Rate ◽  
Experimental Results ◽  
Control Input ◽  
Actual System ◽  
Flexible Arm ◽  
Two Factors ◽  
Measured Position

For vision-based controlled flexible arm, the accuracy of the finite dimensional dynamic models and stability become very important for controller design. This paper addresses the issue of selecting the shape function and mode in developing finite dynamic models, and designs suitable controller for a flexible arm with vision-based control. Input of the controller is the measured position error of the beam tip, which can be directly obtained by camera. In spite of the observed differences between actual system and simulated system, experimental results are good enough to validate the arm model. Simulation and experimental results show that the PID controller is acceptable. It is also stressed that two factors, the camera sampling rate and a dead band in the velocity command, will influence the properties of the control system for vision-based controlled flexible arm.

Nonlinear Model-Based Adaptive Control of a Solenoid-Valve System

2010 ◽  
Author(s):  
DongBin Lee ◽  
C. Nataraj ◽  
Peiman Naseradinmousavi
Keyword(s):  
Dynamic Models ◽  
Controller Design ◽  
Current Source ◽  
Solenoid Valve ◽  
Projection Algorithm ◽  
Control Input ◽  
Valve System ◽  
Multiple Parameters ◽  
Model Based ◽  
Control Objective

In this paper, a model-based control algorithm is developed for a solenoid-valve system. Solenoids and butterfly valves have uncertainties in multiple parameters in the model, which make the system difficult to adjust to the environment. These are further complicated by combining the solenoid and butterfly dynamic models. The control objective of a solenoid-valve system is to position the angle of the butterfly valve through the electric-driven actuator in spite of the complexity presented by uncertainties. The novelty of the controller design is that the current source of the solenoid valve from the model of the electromagnetic force is substituted for the control input in order to reach the set-point of the butterfly disk based on the error signals, overcoming the uncertainties represented by lumped parameters groups, and a stable controller is designed via the Lyapunov-based approach for the stability of the system and obtaining the control objective. The parameter groups are updated by adaptation laws using a projection algorithm. Numerical simulation is shown to demonstrate good performance of the proposed approach.

scholarly journals Improved Model Predictive-Based Underwater Trajectory Tracking Control for the Biomimetic Spherical Robot under Constraints

2020 ◽  
Vol 10 (22) ◽  
pp. 8106
Author(s):  
Xihuan Hou ◽  
Shuxiang Guo ◽  
Liwei Shi ◽  
Huiming Xing ◽  
He Yin ◽  
...  
Keyword(s):  
Trajectory Tracking ◽  
Dynamic Models ◽  
Controller Design ◽  
State Space Model ◽  
Reference Trajectory ◽  
Control Input ◽  
Backstepping Method ◽  
Spherical Robot ◽  
Trajectory Tracking Control ◽  
Improved Model

To improve the autonomy of the biomimetic sphere robot (BSR), an underwater trajectory tracking problem was studied. Considering the thrusters saturation of the BSR, an improved model predictive control (MPC) algorithm that features processing multiple constraints was designed. With the proposed algorithm, the kinematic and dynamic models of the BSR are combined in order to establish the predictive model, and a new state-space model is designed that is based on an increment of the control input. Furthermore, to avoid the infeasibility of the cost function in the MPC controller design, a new term with a slack variable is added to the objective function, which enables the constraints to be imposed as soft constraints. The simulation results illustrate that the BSR was able to track the desired trajectory accurately and stably while using the improved MPC algorithm. Furthermore, a comparison with the traditional MPC shows that the designed MPC-based increment of the control input is small. In addition, a comparative simulation using the backstepping method verifies the effectiveness of the proposed method. Unlike previous studies that only focused on the simulation validations, in this study a series of experiments were carried out that further demonstrate the effectiveness of the improved MPC for underwater trajectory tracking of the BSR. The experimental results illustrate that the improved MPC is able to drive the BSR to quickly track the reference trajectory. When compared with a traditional MPC and the backstepping method used in the experiment, the proposed MPC-based trajectory is closer to the reference trajectory.

Dynamic Anti-Integrator-Windup Controller Design for Linear Systems With Actuator Saturation

2006 ◽  
Vol 129 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Mitsuru Kanamori ◽  
Masayoshi Tomizuka
Keyword(s):  
Linear Systems ◽  
Internal Model ◽  
Controller Design ◽  
Actuator Saturation ◽  
Control Input ◽  
Prime Factorization ◽  
Flexible Arm ◽  
Gain Term ◽  
The One ◽  
Stable Linear

The present paper is concerned with the design of dynamic anti-integrator-windup controllers for critically stable linear systems with a single pole at the origin. The constant gain term in the conventional anti-windup controller is extended to have dynamics represented by a transfer function. The proposed dynamic anti-windup compensator is similar to the one based on co-prime factorization of the plant. The overall controller includes an internal model for constant signals and achieves regulation for constant disturbance and reference inputs as long as the asymptotic control input stays within the saturation limits. The effectiveness of the proposed method is demonstrated on a one-link flexible arm through simulations and experiments.

Dynamic changes in spatial microbial distribution in mixed-population biofilms: experimental results and model simulation

1995 ◽  
Vol 32 (8) ◽  
pp. 67-74 ◽  
Author(s):  
Satoshi Okabe ◽  
Kikuko Hirata ◽  
Yoshimasa Watanabe
Keyword(s):  
Oxygen Diffusion ◽  
Loading Rate ◽  
Model Simulation ◽  
Mixed Population ◽  
Experimental Results ◽  
Synthetic Wastewater ◽  
Diffusion Limitation ◽  
Dynamic Changes ◽  
Microbial Distribution ◽  
Rotating Biological Contactors

Dynamic changes in spatial microbial distribution in mixed-population biofilms were experimentally determined using a microslicer technique and simulated by a biofilm accumulation model (BAM). Experimental results were compared with the model simulation. The biofilms cultured in partially submerged rotating biological contactors (RBC) with synthetic wastewater were used as test materials. Experimental results showed that an increase of substrate loading rate (i.e., organic carbon and NH4-N) resulted in the microbial stratification in the biofilms. Heterotrophs defeated nitrifiers and dominated in the outer biofilm, whereas nitrifiers were diluted out in the outer biofilm and forced into the inner biofilm. At higher organic loading rates, a stronger stratified microbial spatial distribution was observed, which imposed a severe internal oxygen diffusion limitation on nitrifiers and resulted in the deterioration of nitrification efficiency. Model simulations described a general trend of the stratified biofilm structure. However, the actual stratification was stronger than the simulated results. For implication in the reactor design, when the specific carbon loading rate exceeds a certain limit, nitrification will be deteriorated or require a long start-up period due to the interspecies competition resulting in oxygen diffusion limitation. The extend of microbial stratification in the biofilm is especially important for determination of feasibility of nitrification in the presence of organic matters.

scholarly journals A wug-shaped curve in sound symbolism: the case of Japanese Pokémon names

Phonology ◽  
2020 ◽  
Vol 37 (3) ◽  
pp. 383-418
Author(s):  
Shigeto Kawahara
Keyword(s):  
Optimality Theory ◽  
Experimental Results ◽  
Sound Symbolism ◽  
Japanese Speakers ◽  
Linguistic Patterns ◽  
Two Factors ◽  
Evolution Status ◽  
Stochastic Optimality

An experiment showed that Japanese speakers’ judgement of Pokémons’ evolution status on the basis of nonce names is affected both by mora count and by the presence of a voiced obstruent. The effects of mora count are a case of counting cumulativity, and the interaction between the two factors a case of ganging-up cumulativity. Together, the patterns result in what Hayes (2020) calls ‘wug-shaped curves’, a quantitative signature predicted by MaxEnt. I show in this paper that the experimental results can indeed be successfully modelled with MaxEnt, and also that Stochastic Optimality Theory faces an interesting set of challenges. The study was inspired by a proposal made within formal phonology, and reveals important previously understudied aspects of sound symbolism. In addition, it demonstrates how cumulativity is manifested in linguistic patterns. The work here shows that formal phonology and research on sound symbolism can be mutually beneficial.

scholarly journals Super-Twisting Algorithm Applied to Velocity Control of DC Motor without Mechanical Sensors Dependence

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6041
Author(s):  
Fredy A. Valenzuela ◽  
Reymundo Ramírez ◽  
Fermín Martínez ◽  
Onofre A. Morfín ◽  
Carlos E. Castañeda
Keyword(s):  
Controller Design ◽  
Sliding Mode ◽  
Dc Motor ◽  
Experimental Results ◽  
Resistive Load ◽  
Velocity Control ◽  
Velocity Sensor ◽  
Control Scheme ◽  
Mechanical Sensors ◽  
Twisting Algorithm

A DC motor velocity control in feedback systems usually requires a velocity sensor, which increases the controller cost. Additionally, the velocity sensor used in industrial applications presents several disadvantages such as maintenance requirements and signal conditioning. In this work, we propose a robust velocity control scheme applied to a DC motor based on estimation strategies using a sliding-mode observer. This means that measurements with mechanical sensors are not required in the controller design. The proposed observer estimates the rotational velocity and load torque of the motor. The controller design applies the exact-linearization technique combined with the super-twisting algorithm to achieve robust performance in the closed-loop system. The controller validation was carried out by experimental tests using a workbench, which is composed of a control and data acquisition Digital Signal Proccessor board, a DC-DC electronic converter, an interface board for signals conditioning, and a DC electric generator connected to an adjustable resistive load. The simulation and experimental results show a significant performance of the proposed control scheme. During tests, the accuracy, robustness, and speed response on the controller were evaluated and the experimental results were compared with a classic proportional-integral controller, which uses a conventional encoder.

scholarly journals Characterization of Moisture Diffusion in Cured Concrete Slabs at Early Ages

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Xiao Zhang ◽  
Hongduo Zhao
Keyword(s):  
Process Model ◽  
Model Simulation ◽  
Moisture Diffusion ◽  
Experimental Results ◽  
Concrete Slabs ◽  
Model Parameters ◽  
Early Age ◽  
Water Curing ◽  
Early Age Concrete

The objective of this paper is to investigate the characterization of moisture diffusion inside early-age concrete slabs subjected to curing. Time-dependent relative humidity (RH) distributions of three mixture proportions subjected to three different curing methods (i.e., air curing, water curing, and membrane-forming compounds curing) and sealed condition were measured for 28 days. A one-dimensional nonlinear moisture diffusion partial differential equation (PDE) based on Fick’s second law, which incorporates the effect of curing in the Dirichlet boundary condition using a concept of curing factor, is developed to simulate the diffusion process. Model parameters are calibrated by a genetic algorithm (GA). Experimental results show that the RH reducing rate inside concrete under air curing is greater than the rates under membrane-forming compound curing and water curing. It is shown that the effect of water-to-cement (w/c) ratio on self-desiccation is significant. Lower w/c ratio tends to result in larger RH reduction. RH reduction considering both effect of diffusion and self-desiccation in early-age concrete is not sensitive to w/c ratio, but to curing method. Comparison between model simulation and experimental results indicates that the improved model is able to reflect the effect of curing on moisture diffusion in early-age concrete slabs.

Multi-objective adaptive cruise controller design using nonlinear predictive controller with the objective function with variable weights determined by fuzzy logic controller

2021 ◽  
pp. 095440702110147
Author(s):  
Behzad Samani ◽  
Amir H. Shamekhi
Keyword(s):  
Objective Function ◽  
Fuzzy Logic Controller ◽  
Fuzzy Controller ◽  
Controller Design ◽  
Hierarchical Control ◽  
Control Input ◽  
Cruise Control ◽  
Model Predictive Controller ◽  
Control Step ◽  
Predictive Controller

In this paper, an adaptive cruise control system with a hierarchical control structure is designed. The upper-level controller is a model predictive controller (MPC) that by minimizing an objective function in the presence of the constraints, calculates the desired acceleration as control input and sends it to the lower-level controller. So the lower-level controller, which is a fuzzy controller, determines the amount of throttle valve opening or brake pressure to get the car to this desired acceleration. The model predictive controller performs optimization at each control step to minimize the objective function and achieve the reference values. Usually, the objective function has predetermined and constant weights to meet objectives such as maintain the driver’s desired speed and increase safety and in some cases increase comfort and reduce fuel consumption. In this paper, it is suggested that instead of using constant weights in the objective function, these weights should be determined by a fuzzy controller, depending on the different conditions in which the car is placed. The simulation results show that the variability of the weights of the objective function achieves control objectives much better than the optimization of the objective function with constant weights.

Web Page Ranking Algorithm Based on the Meta-Information

2014 ◽  
Vol 596 ◽  
pp. 292-296
Author(s):  
Xin Li Li
Keyword(s):  
Experimental Results ◽  
High Rank ◽  
Ranking Algorithm ◽  
Web Page ◽  
Page Ranking ◽  
Two Factors ◽  
Meta Information ◽  
The Web

PageRank algorithms only consider hyperlink information, without other page information such as page hits frequency, page update time and web page category. Therefore, the algorithms rank a lot of advertising pages and old pages pretty high and can’t meet the users' needs. This paper further studies the page meta-information such as category, page hits frequency and page update time. The Web page with high hits frequency and with smaller age should get a high rank, while the above two factors are more or less dependent on page category. Experimental results show that the algorithm has good results.

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