scholarly journals Coordinated Control of Slip Ratio for Wheeled Mobile Robots Climbing Loose Sloped Terrain

2014 ◽  
Vol 2014 ◽  
pp. 1-13
Author(s):  
Zhengcai Li ◽  
Yang Wang
Keyword(s):  
Control System ◽  
Mobile Robots ◽  
Coordinated Control ◽  
Challenging Problem ◽  
Adaptive Neural Network ◽  
Wheeled Mobile Robots ◽  
Slip Ratio ◽  
Planetary Rovers ◽  
State Variable ◽  
Longitudinal Slip

A challenging problem faced by wheeled mobile robots (WMRs) such as planetary rovers traversing loose sloped terrain is the inevitable longitudinal slip suffered by the wheels, which often leads to their deviation from the predetermined trajectory, reduced drive efficiency, and possible failures. This study investigates this problem using terramechanics analysis of the wheel-soil interaction. First, a slope-based wheel-soil interaction terramechanics model is built, and an online slip coordinated algorithm is designed based on the goal of optimal drive efficiency. An equation of state is established using the coordinated slip as the desired input and the actual slip as a state variable. To improve the robustness and adaptability of the control system, an adaptive neural network is designed. Analytical results and those of a simulation using Vortex demonstrate the significantly improved mobile performance of the WMR using the proposed control system.

Optimal Longitudinal Slip Ratio Allocation and Control of a Hybrid Electric Vehicle With eAWD Capabilities

2016 ◽  
Author(s):  
Jose Velazquez Alcantar ◽  
Francis Assadian ◽  
Ming Kuang ◽  
Eric Tseng
Keyword(s):  
Control System ◽  
Electric Vehicle ◽  
Optimization Algorithm ◽  
Hybrid Electric Vehicle ◽  
Rear Axle ◽  
Surface Condition ◽  
Road Surface ◽  
Slip Ratio ◽  
Hybrid Electric ◽  
Longitudinal Slip

This paper introduces a Hybrid Electric Vehicle (HEV) with eAWD capabilities via the use of a traditional Series-Parallel hybrid transaxle at the front axle and an electric Rear Axle Drive (eRAD) unit at the rear axle. Such a vehicle requires proper wheel torque allocation to the front and rear axles in order to meet the driver demands. A model of the drivetrain is developed using Bond Graphs and is used in co-simulation with a vehicle model from the CarSim software suite for validation purposes. A longitudinal slip ratio control architecture is proposed which allocates slip ratio to the front and real axles via a simple optimization algorithm. The Youla parametrization technique is used to develop robust controllers to track the optimal slip targets generated by the slip ratio optimization algorithm. The proposed control system offers a unified approach to longitudinal vehicle control under both traction and braking events under any road surface condition. It is shown in simulation that the proposed control system can properly allocate slip ratio to the front and rear axles such that tires remain below their force saturation limits while vehicle acceleration/braking is maximized while on a low friction road surface.

scholarly journals Coordinated Control Of Mobile Robots Based On Artificial Vision

2006 ◽  
Vol 1 (2) ◽  
pp. 85 ◽  
Author(s):  
Carlos M. Soria ◽  
Ricardo Carelli ◽  
Rafael Kelly ◽  
Juan M. Ibarra Zannatha
Keyword(s):  
Control System ◽  
Mobile Robots ◽  
Equilibrium Point ◽  
Control Strategy ◽  
Visual Information ◽  
Coordinated Control ◽  
Experimental Results ◽  
Artificial Vision ◽  
Asymptotically Stable ◽  
Multiple Robots

This work presents a control strategy for coordination of multiple robots based on artificial vision to measure the relative posture between them, in order to reach and maintain a specified formation. Given a leader robot that moves about an unknown trajectory with unknown velocity, a controller is designed to maintain the robots following the leader at a certain distance behind, by using visual information about the position of the leader robot. The control system is proved to be asymptotically stable at the equilibrium point, which corresponds to the accomplishment of the navigation objective. Experimental results with two robots, a leader and a follower, are included to show the performance of the vision-based control system.

Stable contour-following control of wheeled mobile robots

Robotica ◽  
2009 ◽  
Vol 27 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Juan Marcos Toibero ◽  
Flavio Roberti ◽  
Ricardo Carelli
Keyword(s):  
Control System ◽  
Mobile Robots ◽  
Control Algorithms ◽  
Wheeled Mobile Robots ◽  
Distance Information ◽  
Straight Wall ◽  
The Stability ◽  
Office Environments ◽  
Wall Following ◽  
Velocity Command

SUMMARYThis paper presents a continuous wall-following controller for wheeled mobile robots based on odometry and distance information. The reference for this controller is the desired distance from the robot to the wall and allows the robot to follow straight wall contour as well as smoothly varying wall contours by including the curvature of the wall into the controller. The asymptotic stability of the control system is proved using a Lyapunov analysis. The controller is designed so as to avoid saturation of the angular velocity command to the robot. A novel switching scheme is also proposed that allows the robot to follow discontinuous contours allowing the robotic system to deal with typical problems of continuous wall-following controllers such as open corners and possible collisions. This strategy overcomes these instances by switching between dedicated behavior-based controllers. The stability of the switching control system is discussed by considering Lyapunov concepts. The proposed control systems are verified experimentally in laboratory and office environments to show the feasibility and good performance of the control algorithms.

Planetary rovers’ wheel–soil interaction mechanics: new challenges and applications for wheeled mobile robots

2010 ◽  
Vol 4 (1) ◽  
pp. 17-38 ◽  
Author(s):  
Liang Ding ◽  
Zongquan Deng ◽  
Haibo Gao ◽  
Keiji Nagatani ◽  
Kazuya Yoshida
Keyword(s):  
Mobile Robots ◽  
Wheeled Mobile Robots ◽  
Planetary Rovers ◽  
New Challenges
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