Asymptotic Solution and Trajectory Planning for Open-Loop Control of Mobile Robots

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Alan Whitman ◽  
Garrett Clayton ◽  
Alexander Poultney ◽  
Hashem Ashrafiuon
Keyword(s):  
Mobile Robots ◽  
Trajectory Planning ◽  
Control Method ◽  
Open Loop ◽  
Order Correction ◽  
Reference Trajectory ◽  
Open Loop Control ◽  
Loop Control ◽  
First Order ◽  
First Order Correction

A novel open-loop control method is presented for mobile robots based on an asymptotic inverse dynamic solution and trajectory planning. The method is based on quantification of sliding by a small nondimensional parameter. Asymptotic expansion of the equations yields the dominant nonslip solution along with a first-order correction for sliding. A trajectory planning is then introduced based on transitional circles between the robot initial states and target reference trajectory. The transitional trajectory ensures smooth convergence of the robot states to the target reference trajectory, which is essential for open-loop control. Experimental results with a differential drive mobile robot demonstrate the significant improvement of the controller performance when the first-order correction is included.

Positioning of Pneumatic Actuator Using Open-Loop System

2015 ◽  
Vol 816 ◽  
pp. 160-164
Author(s):  
Ivan Virgala ◽  
Michal Kelemen ◽  
Erik Prada ◽  
Tomáš Lipták
Keyword(s):  
Mathematical Model ◽  
Control Method ◽  
Open Loop ◽  
Pneumatic Actuator ◽  
Open Loop Control ◽  
Open Loop System ◽  
Precise Positioning ◽  
Loop Control ◽  
Experimental Stand ◽  
Loop Control System

In the paper, we experimentally analyze a pneumatic actuator and possibilities of piston positioning. Paper shows mathematical model of pneumatic actuator. Actuator is experimentally tested and therefor experimental stand is assembled for the purposes of positioning of actuator piston. The changing parameters during the experiment are weight of load and pneumatic pressure. The results show how these parameters can have influence on precise positioning of pneumatic actuator. For experiment there is purposely used open loop control system. The aim of the study is not to show control method for positioning but to show influence of mentioned parameters.

scholarly journals Trajectory Planning for Micromanipulation With a Nonredundant Digital Microrobot: Shortest Path Algorithm Optimization With a Hypercube Graph Representation

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Vincent Chalvet ◽  
Yassine Haddab ◽  
Philippe Lutz
Keyword(s):  
Trajectory Planning ◽  
Graphical Representation ◽  
Open Loop ◽  
Graph Representation ◽  
Open Loop Control ◽  
Algorithm Optimization ◽  
Shortest Path Algorithm ◽  
Loop Control ◽  
Computation Speed

Microrobotics is an ongoing study all over the world for which design is often inspired from macroscale robots. We have proposed the design of a new kind of microfabricated microrobot based on the use of binary actuators in order to generate a highly accurate and repeatable tool for positioning tasks at microscale without any sensor (with open-loop control). Our previous work consisted in the design, modeling, fabrication, and characterization of the first planar digital microrobot. In this paper, we focus on the motion planning of this robot for micromanipulation tasks. The complex motion pattern of this robot requires the use of algorithms. Graph theory is well suited for the discrete workspace generated by this robot. The comparison between several well-known trajectory-planning algorithms is done. A new graphical representation, named the hypercubic graph, is used for improving the computation speed of the algorithm. This is particularly useful for large workspace robots.

Melnikov-Based Open-Loop Control of Escape for a Class of Nonlinear Systems

1997 ◽  
Vol 119 (3) ◽  
pp. 590-594 ◽  
Author(s):  
Emil Simiu ◽  
Marek Franaszek
Keyword(s):  
Stochastic Systems ◽  
Control Method ◽  
Open Loop ◽  
Heteroclinic Orbits ◽  
Time Interval ◽  
Open Loop Control ◽  
Loop Control ◽  
Random Forcing ◽  
Scale Factors ◽  
System Properties

The performance of certain nonlinear stochastic systems is deemed acceptable if during a specified time interval, the systems have sufficiently low probabilities of escape from a preferred region of phase space. We propose an open-loop control method for reducing these probabilities. The method is applicable to stochastic systems whose dissipation- and excitation-free counterparts have homoclinic or heteroclinic orbits. The Melnikov relative scale factors are system properties containing information on the frequencies of the random forcing spectral components that are most effective in inducing escapes. Numerical simulations show that substantial advantages can be achieved in some cases by designing control systems that take into account the information contained in the Melnikov scale factors.

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