Omni-directional robots are becoming more and more common in recent robotic applications. They offer improved ease of maneuverability and effectiveness at the expense of increased complexity. Frequent applications inc...
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ISBN:
(纸本)9789898111319
Omni-directional robots are becoming more and more common in recent robotic applications. They offer improved ease of maneuverability and effectiveness at the expense of increased complexity. Frequent applications include but are not limited to robotic competitions and service robotics. The goal of this work is to find a precise dynamical model in order to predict the robot behavior. Models were found for two real world omni-directional robot configurations and their parameters estimated using a prototype that can have 3 or 4 wheels. Simulations and experimental runs are presented in order to validate the presented work.
This research applies the grey wolf optimization algorithm which includes the feature selection stage and implements borda count method to optimize the function selection problem in classification. The grey wolf optim...
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ISBN:
(纸本)9781538666630
This research applies the grey wolf optimization algorithm which includes the feature selection stage and implements borda count method to optimize the function selection problem in classification. The grey wolf optimization mimics the characteristics and movement of wolves which have more than one leader in a pack. The proposed algorithm presents the pack can have more than one pack which selects the most relevant features. The performance of proposed algorithm is compared with other classification techniques such as cAnt-Miner, C4.5 and PART. The experimental results show that the proposed algorithm is capable to optimized feature selection in classification problems.
The article deals with the issues of rational use of material and human resources of structural units of energy services of enterprises. Periodic statistics do not fully reflect dynamic processes. Forecasting should f...
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A novel adaptive sliding mode control (ASMC) algorithm is derived to deal with seam tracking control problem of welding robotic manipulator, during the process of large-scale structure component welding. The controlle...
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ISBN:
(纸本)9789897580406
A novel adaptive sliding mode control (ASMC) algorithm is derived to deal with seam tracking control problem of welding robotic manipulator, during the process of large-scale structure component welding. The controllers robustness is verified by the Lyapunov stability theory, and the analytical results show that the proposed algorithm enables better high-precision tracking performance with chattering-free than classic sliding mode control (SMC) algorithm.
The proposed work is devoted to the study of a two-dimensional problem with free boundaries, which arises in the mathematical modeling of medical problems. A new formulation of the two-dimensional problem with free bo...
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In continuous vertical descent, multi-rotor UAVs39; attitude will meet the problem of attitude fluctuation and tends to divergence. The problem comes from the flight controller instead of vortex-ring state. Based on...
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ISBN:
(纸本)9781510873377
In continuous vertical descent, multi-rotor UAVs' attitude will meet the problem of attitude fluctuation and tends to divergence. The problem comes from the flight controller instead of vortex-ring state. Based on an eight-rotor UAV's nonlinear model in hovering mode, the control law is analysed by using transfer function. The first reason is that the inner ring and outer ring bandwidths of the PID cascade controller do not match well. And the other one is that the lower linear operating point and lower average rotor speed during descent lead to less thrust and torque per propeller, which make it more difficult to resist wind disturbances. By adjusting the position loop's parameters in descent, the eight-rotor UAV reduced the requirement of horizontal position accuracy, and the stability of horizontal attitude control increased, which finally obtained a better performance.
Localization is the problem of determining a robot39;s location in an environment. Monte Carlo Localization (MCL) is a method of solving this problem by using a partially observable Markov decision process to find t...
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ISBN:
(纸本)9728865600
Localization is the problem of determining a robot's location in an environment. Monte Carlo Localization (MCL) is a method of solving this problem by using a partially observable Markov decision process to find the robot's state based on its sensor readings, given a static map of the environment. MCL requires a model of each sensor in order to work properly. One of the most important sensors involved is the estimation of the robot's motion, based on its encoders that report what motion the robot has performed. Since these encoders are inaccurate, MCL involves using other sensors to correct the robot's location. Usually, a motion model is created that predicts the robot's actual motion, given a reported motion. The parameters of this model must be determined manually using exhaustive tests. Although an accurate motion model can be determined in advance, a single model cannot optimally represent a robot's motion in all cases. With a terrestrial robot the ground surface, slope, motor wear, and possibly tire inflation level will all alter the characteristics of the motion model. Thus, it is necessary to have a generalized model with enough error to compensate for all possible situations. However, if the localization algorithm is working properly, the result is a series of predicted motions, together with the corrections determined by the algorithm that alter the motions to the correct location. In this case, we demonstrate a technique to process these motions and corrections and dynamically determine revised motion parameters that more accurately reflect the robot's motion. We also link these parameters to different locations so that area dependent conditions, such as surface changes, can be taken into account. These parameters might even be used to identify surface changes by examining the various parameters. By using the fact that MCL is working, we have improved the algorithm to adapt to changing conditions so as to handle even more complex situations.
In this paper, we propose a high order approximation for generalized Caputo fractional derivative of order alpha is an element of (0;1). The approximation order is shown to be O(tau(3-alpha)) which improves some previ...
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ISBN:
(纸本)9781665476874
In this paper, we propose a high order approximation for generalized Caputo fractional derivative of order alpha is an element of (0;1). The approximation order is shown to be O(tau(3-alpha)) which improves some previous work done to date. We then apply the new approximation to solve a class of generalized time fractional sub-diffusion problem. Some experiments are carried out to demonstrate the accuracy of the proposed methods. The numerical results indicate consistency with the theoretical results and good performance of the methods.
This paper presents a novel 2R parallel mechanism used as alt-azimuth pedestal, i. e. a 2-DOF (degree-of-freedom) pedestal for supporting and rotating equipment about two perpendicular axes. Its active joints are two ...
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This paper presents a novel 2R parallel mechanism used as alt-azimuth pedestal, i. e. a 2-DOF (degree-of-freedom) pedestal for supporting and rotating equipment about two perpendicular axes. Its active joints are two sliders equipped with servo control on a circular rail. The synchronous and asynchronous motions of the two sliders lead to the azimuth (rotation about the vertical axis) and pitch (rotation about the horizontal axis) of the rotatable platform, respectively. The DOF computation and kinematics are dealt with firstly, and then the dynamic model of the 2R parallel mechanism is established by using the Lagrange equation. Eventually, a numerical simulation of the typical trajectory motion is carried out, and the actuating torque needed in the actuators for the trajectory tracking motion is worked out by employing the derived inverse dynamic equations, which is consistent with the result obtained from commercial software. This study lays a solid base for the further investigation and engineering implementation of the 2R parallel mechanism.
Considering the problem of trajectory planning of redundant degree of freedom in autonomous operation for excavating robot, a method of trajectory planning for periodic operation of autonomous excavating robot based o...
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Considering the problem of trajectory planning of redundant degree of freedom in autonomous operation for excavating robot, a method of trajectory planning for periodic operation of autonomous excavating robot based on time-jerk synthetic optimum was proposed in this paper. Through a kinematic model establishment and forward/inverse kinematics analysis for working mechanism, the trajectory planning based on Hermite interpolation method was carried out. Taking the time-jerk as objective function, a mathematical model of nonlinear programming under the inequality constraints was established, and Genetic Algorithm was used to find out the globally optimal solution. The rapidity and stability of working process of excavating robot is effectively enhanced and it has an important significance to realize the intelligentization of construction machinery.
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