Jody D Priddy's research while affiliated with United States Army and other places

Publications (29)

Conference Paper
Full-text available
Numerical vehicle performance simulations can be used to better interpret field tests and can give preliminary data for vehicles still in the planning and design stage and no physical prototype yet exists. Although high-fidelity models exist for vehicle mechanics, vehicle-terrain interaction is still in its infancy. The discrete element method (DEM...
Conference Paper
Full-text available
This paper presents an update from a multi-year research program to create and expand the Database Records for Off-road Vehicle Environments (DROVE), one of the most comprehensive physical testing databases for off-road vehicles in existence. DROVE was created and has been expanded by a multi-year data mining effort through published and unpublishe...
Article
With over 8000 field and laboratory tests, the Database for Off-Road Vehicle Environments (DROVE) provides a consolidated database of parameters for the assessment of tracked and wheeled vehicles on fine-and coarse-grained soils. This paper presents a new release of DROVE, version 2.0, which adds 294 results from the test performed by powered and u...
Article
The one-pass vehicle cone index (VCI1) is a measurement of the softest soil over which a vehicle can consistently drive at least once. In the last few decades, VCI1 has become a common quantitative indicator for the soft-soil performance of wheeled and tracked ground vehicles. Because VCI1 depends on not only the strength (as measured by Cone Index...
Article
Vehicle traction between the wheel and the ground surface is a critical design element for on-road and off-road mobility. Adequate traction in dry sand relates to the vehicle’s ability to negotiate deserts, sand dunes, climb slopes, and ingress/egress along beaches. The existing traction equations predict values for only one mode of operation (brak...
Article
The Vehicle-Terrain Interface (VTI) model for off-road vehicle performance is often used in virtual proto-typing to support preliminary vehicle design. Five VTI algorithms for wheeled vehicles on fine-grained soils are calibrated in this study using a Bayesian calibration technique and the Database Records for Off-road Vehicle Environments (DROVE):...
Article
The development of high-fidelity, physics-based software for analyzing ground vehicle concept designs and the mobility performance of wheeled and tracked ground vehicles is increasing important. The CREATE-GV toolset’s three modules are integrated to provide a complete performance evaluation of vehicle concept designs.
Article
The Vehicle-Terrain Interface (VTI) model is commonly used to predict off-road mobility to support virtual prototyping. The Database Records for Off-road Vehicle Environments (DROVE), a recently developed database of tests conducted with wheeled vehicles operating on loose, dry sand, is used to calibrate three equations used within the VTI model: d...
Conference Paper
Full-text available
Off-road mobility is an important field of study for agricultural, construction, and military communities. In order to assist with a variety of applications a consolidated database of test results named Database Records Off-road Vehicle Environments (DROVE) has been developed. This paper provides a summary of the current status of DROVE and its rel...
Article
Mercury is a high-fidelity, physics-based object-oriented software for conducting simulations of vehicle performance evaluations for requirements and engineering metrics. Integrating cutting-edge, massively parallel modeling techniques for soft, cohesive and dry granular soil that will integrate state-of-the-art soil simulation with high-fidelity m...
Article
Full-text available
Predicting the resisting forces against a vehicle's wheel during movement in loose sand is critical for optimizing tractive capabilities in desert regions, sand dunes, and beaches. We review existing braked, powered, and towed motion resistance equations and present improved algorithms based on field and laboratory measurements when the cone index...
Article
Full-text available
A gap in off-road mobility is the availability of the test data necessary for the development and validation of tyre, track and soil models. This paper presents the results from a multi-year program to create the database records for off-road vehicle environments (DROVE), a consolidated database of laboratory and field test results. A fine-grained...
Article
Full-text available
A gap in off-road mobility is the availability of the test data necessary for the development and validation of tyre, track and soil models. This paper presents the results from a multi-year program to create the database records for off-road vehicle environments (DROVE), a consolidated database of laboratory and field test results. A fine-grained...
Article
Modeling and simulation of vehicles in sand is critical for characterizing off-road mobility in arid and coastal regions. This paper presents improved algorithms for calculating sinkage (z) of wheeled vehicles operating on loose dry sand. The algorithms are developed based on 2737 tests conducted on sand with 23 different wheel configurations. The...
Conference Paper
Full-text available
This paper presents the results from a multi-year research program to create the Database Records for Off-road Vehicle Environments (DROVE), which is a consolidated database of test results conducted on coarse-and fine-grained soils. Published results were assembled from several technical reports for laboratory and field tests into a database (DROV...
Conference Paper
Full-text available
Effective modelling of off-road vehicle mobility at diverse fidelities and on various terrains is an important task for many vehicle design applications. The Vehicle-Terrain Interface (VTI) model is a low-fidelity model often used to support virtual prototyping of off-road vehicle designs. The VTI model is an assembly of several equations which pre...
Article
A work optimization strategy is combined with algorithms within the vehicle-terrain interface (VTI) model to maximize the traction of a four-wheel vehicle operating on loose dry sand. The optimization model distributes traction among the steered and non-steered wheels with the work optimum coefficient (WOC) of each wheel treated as an independent d...
Article
A substantial number of laboratory and field tests have been conducted to assess performance of various wheel designs in loose soils. However, there is no consolidated database which includes data from several sources. In this study, a consolidated database was created on tests conducted with wheeled vehicles operating in loose dry sand to evaluate...
Conference Paper
Full-text available
A data mining study was performed to consolidate laboratory and field tests for assessing the performance of various wheel designs in sand. The database included wheels of different diameters, widths, heights, and inflation pressures, operating under varying loading conditions. Nine technical reports were identified containing 5,253 records, based...
Conference Paper
Full-text available
_____________________________________________________________________________________ Abstract Test procedures are presented, defining the measured minimum soil strength for a wheeled or tracked vehicle to consistently complete one pass successfully (one-pass Vehicle Cone Index, VCI1). The VCI1 is often used in the procurement process of off-road v...
Article
The cone penetrometer test has been used for decades to quantify the soft soil mobility performance of ground vehicles. As physics-based methods for modeling soil are developed, it is necessary to validate these simulations against databases relating Cone Index (CI) to vehicle mobility. However, in order to make this comparison, the relationship be...
Article
History has repeatedly demonstrated the potentially negative influence of near-surface hydrology on military mobility. Increased moisture and saturation in soil results in a transition from solid to somewhat liquid states. As soil approaches the liquid state, the shear strength available for supporting traffic of ground vehicles or aircraft diminis...
Article
Physics-based simulations of autonomous unmanned ground vehicles (UGV) present unique challenges and advantages compared to real-time simulations with lower-fidelity models. We have created a high-fidelity simulation environment, called the Virtual Autonomous Navigation Environment (VANE), to perform physics-based simulations of UGV. To highlight t...
Article
Full-text available
Simulations provide a safe, controlled setting for testing and are therefore ideal for rapidly developing and testing autonomous mobile robot behaviors. However, algorithms for mobile robots are notorious for transitioning poorly from simulations to fielded platforms. The difficulty can in part be attributed to the use of simplistic sensor models t...
Conference Paper
The Virtual Autonomous Navigation Environment (VANE) is a high-fidelity simulation environment for ground robotics. Physics-based realism is the primary goal of the VANE. The VANE simulation incorporates realistic lighting, vehicle-terrain interaction, environmental attributions, and sensors. The sensor models, including camera, laser ranging, and...
Conference Paper
Full-text available
The research described in this paper is developing a high performance computing simulation testbed to produce a Virtual Autonomous Navigation Environment (VANE). The VANE will facilitate virtual testing of unmanned systems for evaluation of autonomous navigation systems and their associated hardware/software subsystems. The research is using mature...
Article
The US Army developed Vehicle Cone Index (VCI) as a metric for directly quantifying the ability of vehicles to traverse soft-soil terrain. In order to ensure minimum soft-soil performance capabilities for their new military vehicles, the US Army has used VCI for many years as a performance specification. The United Kingdom’s Ministry of Defence (UK...
Article
The approach used here consists of an axisymmetric gage with a tapered exterior. Raw outputs are normal stress in three directions in the plane perpendicular to the gage axis of symmetry. From these outputs, the time history of the complete state of stress in this plane can be determined. Of special interest is the plane of symmetry which is the ve...

Citations

... Du assessed the mechanical properties of soft ground with low moisture, low viscosity and high friction [5]. Peters established a vehicle-terrain simulation model based on the DEM and proved the accuracy of traditional drawbar-pull tests [6]. Zhou proposed a systematic and accurate discrete element modeling method for sandy roads [7]. ...
... Both NTVPM and TPPMTV models have been validated with experimental data. Williams et al. [10] developed and used various field-tested data through "Database for Off-Road Vehicle Environments (DROVE 2.0)" and coupled with various "Vehicle-Terrain Interaction (VTI)" models to analyses mobility performance in terms of drawbar pull, sinkage, and to a extend powered torque for tracked vehicles. ...
... To ascertain gross traction and rolling resistance force of a driving wheel, several mathematical models with various assumptions have been suggested by researchers (Ashmore et al. 1987;Evans et al. 1991;Gee-Clough 1980;Hayes & Ligon 1981;Maclaurin 2014;Mason et al. 2018;Rosca et al. 2014;Sharma & Pandey 1998;Sharma & Pandey 2001;Sitkei 1966;Srivastava et al. 2006;Upadhyaya et al. 1989;Vechinski et al. 1998;Williams et al. 2019;Wismer & Luth 1973;Wismer & Luth 1974;Wulfsohn et al. 1988) based on soil characteristics, size, and slip of the wheel. According to results of review studies conducted by some researchers (Keen et al. 2013;Sunusi et al. 2020;Tiwari et al. 2010), some of the models are limited to specific slip value, tire type (radial-ply and biasply), tested surface and environment, and soil texture (sandy, clay, and silt). ...
... To date, 8473 records are contained in DROVE that span decades of testing with wheeled and tracked vehicles in conjunction with varying soil types. The previous release of DROVE, DROVE 1.0 and associated analysis efforts have focused largely on wheeled vehicles (e.g., Williams et al., 2017a,b;Mason et al., 2016;Dettwiller et al., 2017;Mason et al., 2018;Dettwiller et al., 2018). This paper presents a new release of DROVE, version 2.0, which adds 294 tests from powered and unpowered tracks on fine-grained soils where drawbar pull, motion resistance, sinkage, torque, trim angle, and slip were measured alongside track geometry and loads. ...
... Specifically, strides were made in the accuracy of the DBP, MR, and T equations coarse-grained soils as well as for all five equations for fine-grained soils. In addition to calibration, other statistical analyses of DROVE 1.0 contents have led to the development of improved predictive algorithms for wheeled vehicles Williams et al., 2017Williams et al., , 2019b. ...
... As examples of other types of simulations enabled by Chrono::Vehicle we mention studies of wheeled vehicles with flexible tires on granular terrain [9,10] to investigate the effect of tire and terrain deformation on mobility metrics; and design of model predictive controllers for obstacle avoidance on deformable terrain [19] to investigate controller performance and robustness. Chrono::Vehicle is an integral part of the Mercury framework for mobility simulation of wheeled ground vehicles [32]. ...
... Dettwiller [95] compares the results of simulation and test after calibrating the parameters of vehicle terrain model to estimate the drawbar pull, traction, and motion resistance. Table 4. Identified validation type 1 in automotive vehicle-dynamics analysed according to its use of statistical methods showing the degree of statistical validation (DSV). ...
... To ascertain gross traction and rolling resistance force of a driving wheel, several mathematical models with various assumptions have been suggested by researchers (Ashmore et al. 1987;Evans et al. 1991;Gee-Clough 1980;Hayes & Ligon 1981;Maclaurin 2014;Mason et al. 2018;Rosca et al. 2014;Sharma & Pandey 1998;Sharma & Pandey 2001;Sitkei 1966;Srivastava et al. 2006;Upadhyaya et al. 1989;Vechinski et al. 1998;Williams et al. 2019;Wismer & Luth 1973;Wismer & Luth 1974;Wulfsohn et al. 1988) based on soil characteristics, size, and slip of the wheel. According to results of review studies conducted by some researchers (Keen et al. 2013;Sunusi et al. 2020;Tiwari et al. 2010), some of the models are limited to specific slip value, tire type (radial-ply and biasply), tested surface and environment, and soil texture (sandy, clay, and silt). ...
... Accuracy assessment of soil-tire interaction by direct comparison of simulations to experiments is another important component of test bed development. The assessment is based on comparisons of simulations to physical experiments documented in the DROVE database (Vahedifard et al., 2017). The parameters of interest include the torque T applied at the axle, the drawbar pull force F s , and the slip ratio s r , defined in fractional form as ...
... These parameters are determined by means of the Bevameter test [4]. Because the equipment required is big and the interpretation of the results is not simple, often the usage of the Cone Penetrometer (CP) is preferred to estimate the rolling resistance and performance of off-road vehicles [5]. CP is a portable device to measure the strength of the soil. ...