Tire-Terrain Normal and Longitudinal Dynamics and Slip Power Losses of an Unmanned Ground Vehicle

2013 ◽  
Author(s):  
Mostafa Salama ◽  
Vladimir V. Vantsevich
Keyword(s):  
Rolling Resistance ◽  
Computational Time ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicles ◽  
Power Losses ◽  
Ground Vehicle ◽  
Longitudinal Dynamics ◽  
Straight Line ◽  
On Line ◽  
Terrain Characteristics

Studies of the tire-terrain interaction have mostly been completed on vehicles with steered wheels, but not much work has been done regarding skid-steered Unmanned Ground Vehicles (UGV). This paper introduces a mathematical model of normal and longitudinal dynamics of a UGV with four skid-steered pneumatic tire wheels. Unlike the common approach, in which two wheels at each side are treated as one wheel (i.e., having the same rotational speeds), all four wheels in this study are independently driven. Thus the interaction of each tire with deformable terrain is introduced as holonomic constraints. The stress-strain characteristics for tire-soil interaction are analyzed based on modern Terramechanics methods and then further used to determine the circumferential wheel forces of the four tires. Contributions of three components of each tire circumferential force to tire slippages are modeled and analyzed when the tire normal loads vary during vehicle straight-line motion. The considered tire-soil characteristics are mathematically reduced to a form that allows condensing the computational time for on-line computing tire-terrain characteristics. Additionally, rolling resistance of the tires is analyzed and incorporated in the UGV dynamic equations. Moreover, the paper describes the physics of slip power losses in the tire-soil interaction of the four tires and applies it to small skid-steered UGV. This study also formulates an optimization problem of the minimization of the power losses in the tire-soil interactions due to the tire slippage.

scholarly journals Towards Energy Efficient Follow Behaviors for Unmanned Ground Vehicles Over Rugged Terrains

2012 ◽  
Author(s):  
Madan M. Dabbeeru ◽  
Joshua D. Langsfeld ◽  
Petr Svec ◽  
Satyandra K. Gupta
Keyword(s):  
State Space ◽  
Energy Efficient ◽  
The State ◽  
Unmanned Ground Vehicles ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicles ◽  
Ground Vehicle ◽  
Rugged Terrain ◽  
Simulation Results ◽  
The Relationship

This paper focuses on the development of a follow behavior for an unmanned ground vehicle (UGV) in collaborative scenarios. The scenario being studied involves a human traveling over a rugged terrain on foot. The UGV follows the human. We present an approach for automatically generating a reactive energy-efficient follow behavior that maps the vehicle’s states into motion goals. We start by partitioning the state space that encodes the relationship between the state of the vehicle and the human’s state, and the environment. For each cell in the partitioned state space, we either directly generate the motion goal for the vehicle to execute or a function that produces the motion goal. The motion goal defines not only the location towards which the vehicle should move but also specifies a zero activity zone around the human within which the vehicle is supposed to slow down and remain stationary to save its energy until it gets outside the margin caused by the movement of the human. Our approach utilizes off-line simulations to assess the performance of the generated behavior. Our simulation results show that the automatically generated follow behavior significantly outperforms a simple conservative tracking rule in terms of distance traveled and violation of proximity constraints. We anticipate that the approach presented in this paper will ultimately enable us to implement energy efficient follow behaviors on physical UGVs.

Mechatronics Implementation of Inverse Dynamics-Based Controller for an Off-Road UGV

2015 ◽  
Author(s):  
Mostafa Salama ◽  
Vladimir V. Vantsevich
Keyword(s):  
Power Distribution ◽  
Control Algorithm ◽  
Inverse Dynamics ◽  
Dc Motor ◽  
Unmanned Ground Vehicle ◽  
Power Losses ◽  
Wheel Load ◽  
Ground Vehicle ◽  
Dc Motors ◽  
And Control

This paper presents a project developed at the University of Alabama at Birmingham (UAB) aimed to design, implement, and test an off-road Unmanned Ground Vehicle (UGV) with individually controlled four drive wheels that operate in stochastic terrain conditions. An all-wheel drive off-road UGV equipped with individual electric dc motors for each wheel offers tremendous potential to control the torque delivered to each individual wheel in order to maximize UGV slip efficiency by minimizing slip power losses. As previous studies showed, this can be achieved by maintaining all drive wheels slippages the same. Utilizing this approach, an analytical method to control angular velocities of all wheels was developed to provide the same slippages of the four wheels. This model-based method was implemented in an inverse dynamics-based control algorithm of the UGV to overcome stochastic terrain conditions and minimize wheel slip power losses and maintain a given velocity profile. In this paper, mechanical and electrical components and control algorithm of the UGV are described in order to achieve the objective. Optical encoders built-in each dc motor are used to measure the actual angular velocity of each wheel. A fifth wheel rotary encoder sensor is attached to the chassis to measure the distance travel and estimate the longitudinal velocity of the UGV. In addition, the UGV is equipped with four electric current sensors to measure the current draw from each dc motor at various load conditions. Four motor drivers are used to control the dc motors using National Instruments single-board RIO controller. Moreover, power system diagrams and controller pinout connections are presented in detail and thus explain how all these components are integrated in a mechatronic system. The inverse dynamics control algorithm is implemented in real-time to control each dc motors individually. The integrated mechatronics system is distinguished by its robustness to stochastic external disturbances as shown in the previous papers. It also shows a promising adaptability to disturbances in wheel load torques and changes in stochastic terrain properties. The proposed approach, modeling and hardware implementation opens up a new way to the optimization and control of both unmanned ground vehicle dynamics and vehicle energy efficiency by optimizing and controlling individual power distribution to the drive wheels.

Research on Inductive Power Charging Device of Unmanned Ground Vehicle

2014 ◽  
Vol 852 ◽  
pp. 660-664
Author(s):  
Zhi Ning Li ◽  
Jian Wei Chen ◽  
Ying Tang Zhang ◽  
Gang Yin
Keyword(s):  
Power Converter ◽  
Air Gap ◽  
Constant Current ◽  
Resonant Circuit ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicles ◽  
Ground Vehicle ◽  
Charging System ◽  
Series Resonant ◽  
Inductive Power

It is important to charge accumulator automatically on unmanned ground vehicles. A kind of inductive power charging system, with rotary type coupler and series-resonant power converter of full bridge, is designed. The working progress of resonant circuit and main circuit is simulated. The result of experiments shows that the simulation model of main circuit agrees well with practice and can instruct design of power converter in the future. The efficiency of power transferring decreases with coupler air gap increasing. The designed inductive charging device can charge accumulator with constant current while the air gap is 1.2 mm.

Motion and Energy Efficiency Parameters of the Unmanned Ground Vehicle

2015 ◽  
Vol 220-221 ◽  
pp. 934-939 ◽  
Author(s):  
Eero Väljaots ◽  
Raivo Sell ◽  
Mati Kaeeli
Keyword(s):  
Energy Efficiency ◽  
Data Acquisition ◽  
Real Time ◽  
Design Process ◽  
Field Tests ◽  
Unmanned Ground Vehicles ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicles ◽  
Ground Vehicle ◽  
Acquisition Method

The paper investigates the data acquisition method and a system of wheeled mobile unmanned ground vehicles (UGV) for characterization and optimization of motion and energy efficiency. This enables to conduct real-time and conditional field tests. The obtained results are used for an advanced methodology framework for robotic design targeted on the development, simulation and testing of vehicle platforms along the entire design process.

scholarly journals Multi-Role Unmanned Ground Vehicle for Bomb Detection and Surveillance

2019 ◽  
Vol 8 (6S2) ◽  
pp. 558-561
Keyword(s):  
Modular Design ◽  
Robotic Arm ◽  
Unmanned Ground Vehicles ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicles ◽  
Metal Detector ◽  
Security Forces ◽  
Ground Vehicle ◽  
Emergency Operations ◽  
Key Aspects

Nowadays the world is very insecure due to various problems like terrorism , natural disasters , emergency health situations and surveillance. Valuable lives are being lost in various situation due to human negligence when carrying out rescue or emergency operations. Even though when our security forces are tireless working to save us everyday , we still have problem to entirely secure ourselves in different situation. To counter these issues we propose a project. Our project is a multi-role capable unmanned ground vehicle. It has three key aspects the modular design , robotic arm and surveillance The current types of unmanned ground vehicles are designed for doing only one specific task like handling a bomb or only carrying payloads but our unmanned ground vehicle is designed to undertake multiple tasks. When required the unmanned ground vehicle can be fitted with a robotic arm , metal detector or storage compartment for carrying supplies and even wireless camera for surveillance .The operations to be performed are done using two control methods RF control and through microcontroller chips. By implementing a mix of modular design, simple and cheap circuitry we can develop an effective and reliable multi-role capable unmanned ground vehicles.

Magnetic surveying with an unmanned ground vehicle

2018 ◽  
Vol 6 (4) ◽  
pp. 249-266
Author(s):  
A. Hay ◽  
C. Samson ◽  
L. Tuck ◽  
A. Ellery
Keyword(s):  
Separation Distance ◽  
Field Conditions ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicles ◽  
Ground Vehicle ◽  
Development Platform ◽  
Full Speed ◽  
Aerial Vehicle ◽  
The Impact ◽  
Vehicle Market

With the recent proliferation of unmanned aerial vehicles for geophysical surveying, a novel opportunity exists to develop unmanned ground vehicles in parallel. This contribution features a study to integrate the Husky A200 robotic development platform with a GSMP 35U magnetometer that has recently been developed for the unmanned aerial vehicle market. Methods to identify and reduce the impact of magnetically noisy components on the unmanned ground vehicle platforms are discussed. The noise generated by the platform in laboratory and gentle field conditions, estimated using the fourth difference method for a magnetometer–vehicle separation distance of 121 cm and rotation of the chassis wheels at full speed (1 m/s), is ±1.97 nT. The integrated unmanned ground vehicle was used to conduct two robotic magnetic surveys to map cultural targets and natural variations of the magnetic field. In realistic field conditions, at a full speed of 1 m/s, the unmanned ground vehicle measured total magnetic intensity over a range of 1730 nT at 0.1 m spatial resolution with a productivity of 2651 line metres per hour.

scholarly journals Can you feel it? What does it mean? Notifications for Operators of Unmanned Ground Vehicles (UGVs) During Operational Missions

2019 ◽  
Vol 63 (1) ◽  
pp. 817-821
Author(s):  
Nuphar Katzman ◽  
Tal Oron-Gilad
Keyword(s):  
Performance Metrics ◽  
Response Times ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicles ◽  
Semantic Meaning ◽  
Ground Vehicle ◽  
Sensory Modalities ◽  
Series Of Experiments ◽  
Tactile Interfaces ◽  
Tactile Modality

Vibro-tactile interfaces can support users in various aspects and contexts. Despite their inherent advantages, it is important to realize that they are limited in the type and capacity of information they can convey. This study is part of a series of experiments that aim to develop and evaluate a “tactile taxonomy” for dismounted operational environments. The current experiment includes a simulation of an operational mission with a remote Unmanned Ground Vehicle (UGV). During the mission, 20 participants were required to interpret notifications that they received in one (or more) of the following modalities: auditory, visual and/or tactile. Three specific notification types were chosen based on previous studies, in order to provide an intuitive connection between the notification and its semantic meaning. Response times to notifications, the ability to distinguish between the information types that they provided, and the operational mission performance metrics, were collected. Results indicate that it is possible to use a limited “tactile taxonomy” in a visually loaded and auditory noisy scene while performing a demanding operational task. The use of the tactile modality with other sensory modalities leverages the participants’ ability to perceive and identify the notifications.

scholarly journals Coverage path planning for a flock of aerial vehicles to support autonomous rovers through traversability analysis

ACTA IMEKO ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 9 ◽  
Author(s):  
Dario Calogero Guastella ◽  
Luciano Cantelli ◽  
Domenico Longo ◽  
Carmelo Donato Melita ◽  
Giovanni Muscato
Keyword(s):  
Path Planning ◽  
Autonomous Navigation ◽  
Complete Solution ◽  
Volcanic Eruptions ◽  
Aerial Imagery ◽  
Unmanned Ground Vehicle ◽  
Ground Vehicles ◽  
Ground Vehicle ◽  
Coverage Path Planning ◽  
Definition Of

In rough terrains, such as landslides or volcanic eruptions, it is extremely complex to plan safe trajectories for an Unmanned Ground Vehicle (UGV), since both robot stability and path execution feasibility must be guaranteed. In this paper, we present a complete solution for the autonomous navigation of ground vehicles in the mentioned scenarios. The proposed solution integrates three different aspects. The first is the coverage path planning for the definition of UAV trajectories for aerial imagery acquisition. The collected images are used for the photogrammetric reconstruction of the considered area. The second aspect is the adoption of a flock of UAVs to implement the coverage in a parallel way. In fact, when non-coverable zones are present, decomposition of the whole area to survey is performed. A solution to assign the different regions among the flying vehicles composing the team is presented. The last aspect is the path planning of the ground vehicle by means of a traversability analysis performed on the terrain 3D model. The computed paths are optimal in terms of the difficulty of moving across the rough terrain. The results of each step within the overall approach are shown.

Design and Realization of an All-terrain Unmanned Ground Vehicle

ROBOT ◽  
2013 ◽  
Vol 35 (6) ◽  
pp. 657 ◽  
Author(s):  
Taoyi ZHANG ◽  
Tianmiao WANG ◽  
Yao WU ◽  
Qiteng ZHAO
Keyword(s):  
Unmanned Ground Vehicle ◽  
Ground Vehicle
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