An obstacle avoidance algorithm for space hyper-redundant manipulators using combination of RRT and shape control method

Robotica ◽  
2021 ◽  
pp. 1-34
Author(s):  
Xiaobo Zhang ◽  
Jinguo Liu ◽  
Yangmin Li
Keyword(s):  
Obstacle Avoidance ◽  
Shape Control ◽  
Control Method ◽  
Random Tree ◽  
Redundant Manipulators ◽  
Control Methods ◽  
Backbone Curve ◽  
Tree Algorithm

Abstract This paper proposes a kinematic obstacle avoidance algorithm for Space hyper-redundant manipulators, and its basic idea is to use a static and a dynamic curve to constrain the macroshape of the manipulators simultaneously. The static curve is constructed based on a traditional rapidly exploring random tree algorithm, and a backbone curve is utilized as the dynamic curve. For these two curves, two novel shape control methods are proposed to accomplish the shape constraining process. Finally, we verify the reliability and effectiveness of our algorithm through simulations.

Obstacle Avoidance for 2D Hyper-Redundant Manipulators Using Harmonic Potential Functions and the Mode Shape Technique

2001 ◽  
Author(s):  
F. Fahimi ◽  
H. Ashrafiuon ◽  
C. Nataraj
Keyword(s):  
Obstacle Avoidance ◽  
Dimensional Space ◽  
Potential Functions ◽  
Harmonic Potential ◽  
Redundant Manipulators ◽  
Two Dimensional ◽  
Algebraic Equations ◽  
Backbone Curve ◽  
Cluttered Environments ◽  
Fitting Method

Abstract Obstacle avoidance for discrete-link two-dimensional (2D) hyper-redundant manipulators in known environments is considered. The manipulator is divided into two sections, a proximal section that has not entered the space among obstacles and a distal section among the obstacles. Harmonic potential functions were used, in order to avoid local minima in cluttered environments. A modified panel method is used to generate the potential of any arbitrary shaped obstacle in two-dimensional space. An alternative backbone curve concept and an efficient fitting method are introduced to control the trajectory of proximal links. The fitting method is recursive and avoids the complications involved with solving large systems of nonlinear algebraic equations. Combination of the safe path derived from the harmonic potential field and the backbone curve concept leads to an elegant kinematic control strategy that guarantees obstacle avoidance for planar hyper-redundant robotic manipulators.

Exploration on Shape of Profiles Determined by Chord Angle Control Method

2011 ◽  
Vol 314-316 ◽  
pp. 837-841
Author(s):  
Ling Ling ◽  
Yuan Sheng Zeng
Keyword(s):  
Theoretical Basis ◽  
Control Method ◽  
Angle Measurement ◽  
Mapping Method ◽  
Control Methods ◽  
Forming Process ◽  
Spline Curve ◽  
Curve Line ◽  
Line Measure

Through compassion of relative merits of the existing two control methods of straighten anti-curve line and chord line measure for cold-formed profiles, a three-pivot chord angle control method of non-endpoint measurement was proposed in this paper, and its feasibility was proved by using mathematical deduction. Using mapping method, the forming of profiles can be controlled by the only one set of orderly array chord angles and chord lines obtained by a spline curve of profiles, and meanwhile, the length of automation feedstock in forming process of profiles was explored. The present research achievements can provide a good theoretical basis for the further application on controlling profile forming with the chord angle measurement.

scholarly journals Emulation of grid-forming inverters using real-time PC and 4-quadrant voltage amplifier

2021 ◽  
Author(s):  
Wolf Schulze ◽  
Maurizio Zajadatz ◽  
Michael Suriyah ◽  
Thomas Leibfried
Keyword(s):  
Real Time ◽  
Control Method ◽  
Current Control ◽  
Control Methods ◽  
Test Bed ◽  
Test Scenario ◽  
Power Semiconductors ◽  
Voltage Amplifier ◽  
Grid Side ◽  
Virtual Synchronous Machine

AbstractA test bed for the evaluation of novel control methods of inverters for renewable power generation is presented. The behavior of grid-following and grid-forming control in a test scenario is studied and compared.Using a real-time capable control platform with a cycle time of 50 µs, control methods developed with Matlab/Simulink can be implemented. For simplicity, a three-phase 4‑quadrant voltage amplifier is used instead of an inverter. Thus, the use of modulation and switched power semiconductors can be avoided. In order to show a realistic behavior of a grid-side filter, passive components can be automatically connected as L‑, LC- or LCL-filter. The test bed has a nominal active power of 43.6 kW and a nominal voltage of 400 V.As state-of-the-art grid-following control method, a current control in the d/q-system is implemented in the test bed. A virtual synchronous machine, the Synchronverter, is used as grid-forming control method. In combination with a frequency-variable grid emulation, the behavior of both control methods is studied in the event of a load connection in an island grid environment.

A compliant control method for disassembly of non-elastic parts using realised motion

Robotica ◽  
1995 ◽  
Vol 13 (6) ◽  
pp. 591-598 ◽  
Author(s):  
Yagmur Denizhan
Keyword(s):  
Control Method ◽  
Recognition System ◽  
Automatic Recognition ◽  
Human Operator ◽  
Control Methods ◽  
Compliant Control ◽  
On Line

SummaryIn disassembly tasks, due to the large variety of objects and the different positions and orientations in which they appear, the disassembly trajectories supplied on-line by a human operator or an automatic recognition system can contain large errors. The classical compliant control methods turn out to be insufficient to eliminate sticking which is due to these errors. This paper presents a compliant control method for disassembly of non-elastic parts in non-elastic environments which adopts the trajectories according to realised motion. In case of sticking a new direction of motion is searched for until the manipulated part is set into motion.

Modelling and control of manipulators with flexible links working on land and underwater environments

Robotica ◽  
2010 ◽  
Vol 29 (3) ◽  
pp. 461-470 ◽  
Author(s):  
Levent Gümüşel ◽  
Nurhan Gürsel Özmen
Keyword(s):  
Fuzzy Control ◽  
Control Method ◽  
Robot Manipulator ◽  
Control Methods ◽  
Control Laws ◽  
Linear Ordinary Differential Equations ◽  
Intelligent Technique ◽  
Wide Range ◽  
Classical Control ◽  
And Control

SUMMARYIn this study, modelling and control of a two-link robot manipulator whose first link is rigid and the second one is flexible is considered for both land and underwater conditions. Governing equations of the systems are derived from Hamilton's Principle and differential eigenvalue problem. A computer program is developed to solve non-linear ordinary differential equations defining the system dynamics by using Runge–Kutta algorithm. The response of the system is evaluated and compared by applying classical control methods; proportional control and proportional + derivative (PD) control and an intelligent technique; integral augmented fuzzy control method. Modelling of drag torques applied to the manipulators moving horizontally under the water is presented. The study confirmed the success of the proposed integral augmented fuzzy control laws as well as classical control methods to drive flexible robots in a wide range of working envelope without overshoot compared to the classical controls.

Design and Error Estimates of Cut Tobacco Feeding by Wind System

2013 ◽  
Vol 722 ◽  
pp. 447-453
Author(s):  
Xiao Zhong Zhou
Keyword(s):  
Control Method ◽  
Production Quality ◽  
Control Methods ◽  
Wind System ◽  
Pipe Network ◽  
Process Stability ◽  
Process Indicators ◽  
Transportation Process ◽  
Cut Tobacco ◽  
Control Accuracy

The cut tobacco transporting is the absolutely necessarily important tache, whether the transportation process stability is a direct impact on production quality and manufacturing standards. The wind system is adopted by most tobacco companies because of it caused least disruptive of the cut tobacco structure and the pipe network layout of system is flexible, but the wind system is greater influence by itself, different control methods are caused greater difference of process indicators, for example essence and spice ingredients, moisture proportion and smoke flavor. Based on the above reasons, so we need to design the control method of wind system necessarily, in addition we must checkout the control accuracy opportunely, so that it is satisfied by the actual working conditions.

A finite-time H-infinite adaptive fault-tolerant controller considering time delay for flutter suppression of airfoil flutter

2019 ◽  
Vol 234 (2) ◽  
pp. 293-307
Author(s):  
Gao Ming-Zhou ◽  
Chen Xin-Yi ◽  
Han Rong ◽  
Yao Jian-Yong
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Controller Design ◽  
Fault Tolerant ◽  
Linear Matrix ◽  
Control Methods ◽  
Actuator Faults ◽  
Control Delay ◽  
Modeling Uncertainties ◽  
The Stability

To suppress airfoil flutter, a lot of control methods have been proposed, such as classical control methods and optimal control methods. However, these methods did not consider the influence of actuator faults and control delay. This paper proposes a new finite-time H∞ adaptive fault-tolerant flutter controller by radial basis function neural network technology and adaptive fault-tolerant control method, taking into account actuator faults, control delay, modeling uncertainties, and external disturbances. The theoretic section of this paper is about airfoil flutter dynamic modeling and adaptive fault-tolerant controller design. Lyapunov function and linear matrix inequality are employed to prove the stability of the proposed control method of this paper. The numeral simulation section further proves the effectiveness and robustness of the proposed control algorithm of this paper.

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