Path Tracking Experimentation With Epi.q-Mod 2: An Obstacle Climbing Mobile Robot

2016 ◽  
Author(s):  
Giuseppe Quaglia ◽  
Matteo Nisi ◽  
Luca Bruzzone ◽  
Pietro Fanghella
Keyword(s):  
Mobile Robot ◽  
Closed Loop ◽  
Kinematic Model ◽  
Open Loop ◽  
Path Tracking ◽  
Multibody Model ◽  
Experimental Activity ◽  
Robot Trajectory ◽  
Position Controller ◽  
Climbing Ability

In this paper, an experimental activity on the path tracking for a hybrid wheeled-legged mobile robot is presented. The activity has been conducted on the Epi.q-Mod 2 prototype, a mobile robot with obstacle climbing ability. This feature has been obtained using a smart rotating leg architecture. Unfortunately, this solution introduces complexity on the kinematic and dynamic modeling of the robot. In order to understand the behavior of the robot during the motion on a generic trajectory, an open loop position controller has been implemented. In particular, the experimental robot trajectory has been reconstructed from odometric quantities through a simplified kinematic model. This trajectory has been compared with the trajectory obtained from a multibody model of the real prototype in order to evaluate the differences between the two approaches. This activity represents a preliminary step for the development of a self-guidance vehicle. In future works the developed model will be used to provide a position feedback for a closed loop position controller without the necessity to use additional sensors.

A Spatial Linkage Exoskeleton for a Shape-Adaptive Mobile Robot

2019 ◽  
Author(s):  
David E. Geyer ◽  
Cameron J. Turner
Keyword(s):  
Mobile Robot ◽  
Analytical Model ◽  
Spatial Model ◽  
Closed Loop ◽  
Kinematic Model ◽  
Virtual Model ◽  
Actuation Mechanism ◽  
Planar Model ◽  
Future Work ◽  
Initial Research

Abstract With the goal of developing a spatial linkage exoskeleton for a shape-adaptive mobile robot, capable of navigating obstacle-laden environments through changes in geometry, initial research focused on the nature of axis transformations, and parameters affecting linkages, such as the Denavit-Hartenberg (DH) parameters. Building on this background, angulated linkages are developed such that a series of scissor pairs, two angulated linkages connected at their midpoints, forming a closed-loop. Using the DH parameters, the geometries are considered in the development of a planar model. A kinematic model is also developed to replicate the design in future work. A linkage was designed using SolidWorks, and then imported into MATLAB’s Simscape Multibody software where a visual, analytical model was developed. The nominal planar model acts as the basis of a spatial model. Using the spatial model, initial prototypes were built to verify the virtual model. A concept for an actuation mechanism is discussed, with a prototype built to identify any limitations. Through experimentation and analysis of the prototypes, areas for improvement in the design are identified. Future work is discussed to further mature the design and development of this solution.

Visual Servo Control for Wheeled Robot Trajectory Tracking

2011 ◽  
Vol 346 ◽  
pp. 650-656
Author(s):  
Guang Yan Xu ◽  
Xiao Yan Jia ◽  
Hong Shi ◽  
Jian Guo Cui
Keyword(s):  
Mobile Robot ◽  
Trajectory Tracking ◽  
Sliding Mode ◽  
Kinematic Model ◽  
Variable Structure ◽  
Visual Servo ◽  
Trajectory Tracking Control ◽  
Structure Control ◽  
Robot Trajectory ◽  
Sliding Mode Variable Structure

In this paper, we discussed the trajectory tracking control problem of the kinematic model of wheel mobile robot. Designed an asymptotic stability tracking controller, using visual servo method based on inverse system and sliding mode variable structure control, and proposed a method to measure motion state of a target mobile robot. Simulation results show this method is feasible.

Path Tracking Control of Micro-Tracked Mobile Robot

2014 ◽  
Vol 644-650 ◽  
pp. 265-271 ◽  
Author(s):  
Jian Gao ◽  
Shi Long Zhang
Keyword(s):  
Mobile Robot ◽  
Tracking Control ◽  
Tracking Error ◽  
Kinematic Model ◽  
Path Tracking ◽  
Positioning Accuracy ◽  
And Control ◽  
Tracked Mobile Robot ◽  
The Given ◽  
Motor Model

The positioning accuracy of tracked mobile robot is low because of sliding in steering process. Taking the micro-tracked mobile robot as the platform, the interface force between tracks and ground was analyzed, and the motor model, kinematic model and dynamic model were established further. A tracking error controller was built based on the tracking error equations, and the co-simulation of mechanical and control system was applied to predict the robot’s trajectory. That controller was applied on a small tracked mobile robot designed by the authors’ laboratory, and the path tracking experiments with and without obstacles had been done. The results show that the robot can accurately track the given path, whether there are obstacles or not.

Clearance-induced orientation uncertainty of spherical linkages

2021 ◽  
pp. 1-9
Author(s):  
Cody Chan ◽  
Kwun-Lon Ting
Keyword(s):  
Closed Loop ◽  
Kinematic Model ◽  
Parallel Manipulators ◽  
Open Loop ◽  
Joint Clearance ◽  
Worst Case ◽  
End Effector ◽  
Uncertainty Range ◽  
Uncertainty Region ◽  
Spherical Linkages

Abstract This paper proposes a kinematic model to evaluate the orientation uncertainty range of spherical linkages caused by the joint clearances. Based on the concepts of imaginary clearance link, spherical N-bar rotatability laws, and the invariant link rotatability, the uncertainty of the output angle can be treated as a mobility problem. And the uncertainty region of the end-effector is treated as a workspace problem for the remodeled linkage. The paper highlights the orientation error by isolating the kinematic effects of joint clearance from other error factors. The discussion is carried out through spherical four-bar linkages and five-bar linkages. Numeric examples are presented to demonstrate the uncertainty range of the output angle and the uncertainty region of the end-effector. The result shows that, in the worst case, the error of each joint clearance will be magnified in a closed-loop structure compared with linearly adding all the clearance error. This implies that from a kinematics point of view, closed-loop spherical linkages or parallel manipulators will lead to a greater deviation on the end-effector than its open-loop counterpart. Using more passive joints in the manipulator may result in more error possibilities.

Path Tracking Control for a Wheeled Mobile Robot

2010 ◽  
Vol 29-32 ◽  
pp. 2076-2081 ◽  
Author(s):  
Yuan Liang Zhang
Keyword(s):  
Mobile Robot ◽  
Control Strategy ◽  
Tracking Control ◽  
Kinematic Model ◽  
Nonholonomic Constraints ◽  
Path Tracking ◽  
Wheeled Mobile Robot ◽  
Mac Method ◽  
Model Algorithm

In this paper a model algorithm control (MAC) method is proposed to do the path tracking control of a wheeled mobile robot (WMR). This mobile robot is a three-wheel differentially steered wheeled mobile robot subject to nonholonomic constraints. The kinematic model of this mobile robot is presented and used as the mobile robot model to be controlled. Simulations are conducted to show the performance and feasibility of the proposed control strategy for the path tracking of a wheeled mobile robot.

On closed-loop equilibrium strategies for mean-field stochastic linear quadratic problems

2020 ◽  
Vol 26 ◽  
pp. 41
Author(s):  
Tianxiao Wang
Keyword(s):  
Optimal Control ◽  
Closed Loop ◽  
Optimal Control Problems ◽  
Mean Field ◽  
Open Loop ◽  
Time Inconsistency ◽  
Control Problems ◽  
Linear Quadratic ◽  
Linear Quadratic Optimal Control ◽  
Equilibrium Strategies

This article is concerned with linear quadratic optimal control problems of mean-field stochastic differential equations (MF-SDE) with deterministic coefficients. To treat the time inconsistency of the optimal control problems, linear closed-loop equilibrium strategies are introduced and characterized by variational approach. Our developed methodology drops the delicate convergence procedures in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. When the MF-SDE reduces to SDE, our Riccati system coincides with the analogue in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. However, these two systems are in general different from each other due to the conditional mean-field terms in the MF-SDE. Eventually, the comparisons with pre-committed optimal strategies, open-loop equilibrium strategies are given in details.

Comparison of Dc-Dc SEPIC, CUK and Flyback Converters Based LED Drivers

2020 ◽  
pp. 99-107
Author(s):  
Erdal Sehirli
Keyword(s):  
Integrated Circuit ◽  
Closed Loop ◽  
Input Voltage ◽  
Open Loop ◽  
Current Sensor ◽  
Switching Frequency ◽  
Led Driver ◽  
Advantages And Disadvantages ◽  
Led Drivers ◽  
Conduction Mode

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.

scholarly journals Parallel Point Clouds: Hybrid Point Cloud Generation and 3D Model Enhancement via Virtual–Real Integration

2021 ◽  
Vol 13 (15) ◽  
pp. 2868
Author(s):  
Yonglin Tian ◽  
Xiao Wang ◽  
Yu Shen ◽  
Zhongzheng Guo ◽  
Zilei Wang ◽  
...  
Keyword(s):  
Point Cloud ◽  
Closed Loop ◽  
Real Data ◽  
Point Clouds ◽  
Autonomous Driving ◽  
Training Model ◽  
Labor Cost ◽  
Open Loop ◽  
Training Dataset ◽  
Data Annotation

Three-dimensional information perception from point clouds is of vital importance for improving the ability of machines to understand the world, especially for autonomous driving and unmanned aerial vehicles. Data annotation for point clouds is one of the most challenging and costly tasks. In this paper, we propose a closed-loop and virtual–real interactive point cloud generation and model-upgrading framework called Parallel Point Clouds (PPCs). To our best knowledge, this is the first time that the training model has been changed from an open-loop to a closed-loop mechanism. The feedback from the evaluation results is used to update the training dataset, benefiting from the flexibility of artificial scenes. Under the framework, a point-based LiDAR simulation model is proposed, which greatly simplifies the scanning operation. Besides, a group-based placing method is put forward to integrate hybrid point clouds, via locating candidate positions for virtual objects in real scenes. Taking advantage of the CAD models and mobile LiDAR devices, two hybrid point cloud datasets, i.e., ShapeKITTI and MobilePointClouds, are built for 3D detection tasks. With almost zero labor cost on data annotation for newly added objects, the models (PointPillars) trained with ShapeKITTI and MobilePointClouds achieved 78.6% and 60.0% of the average precision of the model trained with real data on 3D detection, respectively.

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