Design and experimental characterization of an omnidirectional unmanned ground vehicle for unstructured terrain

Robotica ◽  
2014 ◽  
Vol 33 (9) ◽  
pp. 1984-2000
Author(s):  
Chenghui Nie ◽  
Marin Assaliyski ◽  
Matthew Spenko
Keyword(s):  
Energy Consumption ◽  
Real World ◽  
Experimental Validation ◽  
Mechanical Design ◽  
Unmanned Ground Vehicle ◽  
Experimental Characterization ◽  
Ground Vehicle ◽  
Confined Spaces ◽  
Outdoor Environments

SUMMARYThis paper describes the design and experimental validation of an omnidirectional unmanned ground vehicle built for operation on real-world, unstructured terrains. The omnidirectional capabilities of this robot give it advantages over skid-steered or Ackermann-steered vehicles in tight and confined spaces. The robot's conventional wheels allow for operation in natural, outdoor environments as compared to omnidirectional robots that use specialized wheels with small, slender rollers and parts that can easily become obstructed with debris and dirt. Additionally, the robot's active split offset caster design allows the robot to kinematically follow continuous but non-differentiable paths and heading angles regardless of its current kinematic configuration. The active split offset caster design also results in less scrubbing torque and therefore less energy consumption during steering as compared to actively steered caster designs. The focus of this paper is the robot's mechanical design as it relates to kinematic isotropy and experimental validation of the design.

Water Hazard Detection Based on 3D LIDAR

2014 ◽  
Vol 668-669 ◽  
pp. 1174-1177 ◽  
Author(s):  
Hai Yan Shao ◽  
Zhen Hai Zhang ◽  
Ke Jie Li ◽  
Jian Wang ◽  
Tao Xu ◽  
...  
Keyword(s):  
Unmanned Ground Vehicle ◽  
Data Format ◽  
Ground Vehicle ◽  
Air Water Interface ◽  
Water Hazard ◽  
Outdoor Environments ◽  
Bodies Of Water ◽  
3D Lidar ◽  
Water Hazards ◽  
Complicated Task

Autonomous off-road navigation is a highly complicated task for a robot or unmanned ground vehicle (UGV) owing to the different kinds of obstacles it could encounter. In-particular, water hazards such as puddles and ponds are very common in outdoor environments and are hard to detect even with ranging devices due to the specular nature of reflection at the air water interface. In recent years, many researches to detect the water bodies have been done. But there still has been very little work on detecting bodies of water that could be navigation hazards, especially at night. In this paper, we used Velodyne HDL-64ES2 3D LIDAR to detect water hazard. The approach first analyzes the data format and transformation of 3D LIDAR, and then writes the data acquisition and visualizations algorithm, integrated data based on ICP algorithm. Finally according the intensity distribution identifies the water hazard. Experiments are carried out on the experimental car in campus, and results show the promising performance.

A Tracked Double-Bodied Vehicle for Use in Outdoor Environments

2017 ◽  
Author(s):  
Michael Benson ◽  
Garrett M. Clayton
Keyword(s):  
Vehicle Dynamics ◽  
Nonlinear Models ◽  
Computation Time ◽  
Contact Forces ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicle ◽  
Surface Conditions ◽  
Outdoor Environments ◽  
Fixed Axis ◽  
Two Bodies

This paper presents an unmanned ground vehicle for use in outdoor environments. The vehicle features a two-bodied design in which the two bodies can rotate relative to each other about a fixed axis. The vehicle uses tracked locomotion for performance in rugged environments and a linear actuator for control of the bodys’ relative orientation. A spring-damper is used to mitigate vibrations due to surface conditions that would add noise to the sensors. A nonlinear model for the vehicle is introduced, and linearized. Design considerations of the suspension system are discussed, including the reduction of vibrations and the maximization of contact forces. Finally, the vehicle dynamics are simulated for the linear and nonlinear models, and the effectiveness and computation time of the two are compared.

scholarly journals Negotiating Uneven Terrain by a Simple Teleoperated Tracked Vehicle with Internally Movable Center of Gravity

2022 ◽  
Vol 12 (1) ◽  
pp. 525
Author(s):  
Yasuhiro Fukuoka ◽  
Kazuyuki Oshino ◽  
Ahmad Najmuddin Ibrahim
Keyword(s):  
Mechanical Design ◽  
Center Of Gravity ◽  
The Body ◽  
Unmanned Ground Vehicle ◽  
Tracked Vehicle ◽  
Ground Vehicle ◽  
High Position ◽  
Uneven Terrain ◽  
Dc Motors ◽  
Mass Position

We propose a mechanical design for a simple teleoperated unmanned ground vehicle (UGV) to negotiate uneven terrain. UGVs are typically classified into legged, legged-wheeled, wheeled, and tanked forms. Legged vehicles can significantly shift their center of gravity (COG) by positioning their multi-articulated legs at appropriate trajectories, stepping over a high obstacle. To realize a COG movable mechanism with a small number of joints, a number of UGVs have been developed that can shift their COG by moving a mass at a high position above the body. However, these tend to pose a risk of overturning, and the mass must be moved quite far to climb a high step. To address these issues, we design a novel COG shift mechanism, in which the COG can be shifted forward and backward inside the body by moving most of its internal devices. Since this movable mass includes DC motors for driving both tracks, we can extend the range of the COG movement. We demonstrate that a conventional tracked vehicle prototype can traverse a step and a gap between two steps, as well as climb stairs and a steep slope, with a human operating the vehicle movement and the movable mass position.

scholarly journals Experimental Validation of Linear and Nonlinear MPC on an Articulated Unmanned Ground Vehicle

2018 ◽  
Vol 23 (5) ◽  
pp. 2023-2030 ◽  
Author(s):  
Erkan Kayacan ◽  
Wouter Saeys ◽  
Herman Ramon ◽  
Calin Belta ◽  
Joshua M. Peschel
Keyword(s):  
Experimental Validation ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicle ◽  
Linear And Nonlinear

scholarly journals An Imaging Network Design for UGV-Based 3D Reconstruction of Buildings

2021 ◽  
Vol 13 (10) ◽  
pp. 1923
Author(s):  
Ali Hosseininaveh ◽  
Fabio Remondino
Keyword(s):  
3D Reconstruction ◽  
Network Design ◽  
Real World ◽  
Continuous Image ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicle ◽  
Localization And Mapping ◽  
Image Capturing ◽  
Slam Algorithm ◽  
Selection Of

Imaging network design is a crucial step in most image-based 3D reconstruction applications based on Structure from Motion (SfM) and multi-view stereo (MVS) methods. This paper proposes a novel photogrammetric algorithm for imaging network design for building 3D reconstruction purposes. The proposed methodology consists of two main steps: (i) the generation of candidate viewpoints and (ii) the clustering and selection of vantage viewpoints. The first step includes the identification of initial candidate viewpoints, selecting the candidate viewpoints in the optimum range, and defining viewpoint direction stages. In the second step, four challenging approaches—named façade pointing, centre pointing, hybrid, and both centre & façade pointing—are proposed. The entire methodology is implemented and evaluated in both simulation and real-world experiments. In the simulation experiment, a building and its environment are computer-generated in the ROS (Robot Operating System) Gazebo environment and a map is created by using a simulated robot and Gmapping algorithm based on a Simultaneously Localization and Mapping (SLAM) algorithm using a simulated Unmanned Ground Vehicle (UGV). In the real-world experiment, the proposed methodology is evaluated for all four approaches for a real building with two common approaches, called continuous image capturing and continuous image capturing & clustering and selection approaches. The results of both evaluations reveal that the fusion of centre & façade pointing approach is more efficient than all other approaches in terms of both accuracy and completeness criteria.

Modeling and Experimental Characterization of a Permanent Magnet Linear Alternator for Free-Piston Engine Applications

2009 ◽  
Author(s):  
Hans T. Aichlmayr ◽  
Peter Van Blarigan
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
Experimental Validation ◽  
Experimental Characterization ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine ◽  
Linear Alternator ◽  
The Mathematical Model

Sandia National Laboratories is developing a prototype 30kW free-piston internal-combustion-based linear generator for vehicular applications. This paper describes the development and experimental validation of a mathematical model for the permanent magnet linear alternator that will be used by the prototype. A magnetic-flux versus mover-position function is used to correlate individual coil fluxes to the motion of the mover. This function is derived from a finite element electromagnetic simulation of the linear alternator. The mathematical model of the alternator is compared to experiments with prototype hardware driving 0.5–2kW loads; excellent correspondence to measured voltage and current waveforms is found.

Sign in / Sign up

Export Citation Format

Share Document