Velocity Selection for High-Speed UGVs in Rough Unknown Terrains Using Force Prediction

Abstract

Abstract. Enabling high speed navigation of Unmanned Ground Vehicles (UGVs) in unknown rough terrain where limited or no information is available in advance requires the assessment of terrain in front of the UGV. Attempts have been made to predict the forces the terrain exerts on the UGV for the purpose of determining the maximum allowable velocity for a given terrain. However, current methods produce overly aggressive velocity profiles which could damage the UGV. This paper presents three novel safer methods of force prediction that produce effective velocity profiles. Two models, Instantaneous Elevation Change Model (IECM) and Sinusoidal Base Excitation Model: using Excitation Force (SBEM:EF), predict the forces exerted by the terrain on the vehicle at the ground contact point, while another method, Sinusoidal Base Excitation Model: using Transmitted Force (SBEM:TF), predicts the forces transmitted to the vehicle frame by the suspension.

Terrain Roughness Identification for High-Speed UGVs

“…Although the local unevenness calculation method from [25] provides a method of measuring variability of the neighbouring normal vectors, essential original geometric point cloud information may have been lost from the fitting of the planes. A method that avoids this potential loss of geometric information is proposed by El-Kabbany and Ramirez-Serrano in [26] and improved by Wilson et al in [27]. This method identifies terrain roughness through the variance of the point elevations in a point cloud.…”

“…The method of terrain identification through geometric based roughness identification proposed by El-Kabbany and Ramirez-Serrano in [26] and improved by Wilson et al in [27] provides a measure of the level of traversability of terrain and is a promising technique. The work in [26] and [27] provides the theoretical basis for this terrain identification technique; however, this work does not fully investigate the challenges of implementing such a technique on a real-world UGV platform, not does it provide experimental testing and results of this technique operating on a moving UGV in typical outdoor terrains.…”

“…The work in [26] and [27] provides the theoretical basis for this terrain identification technique; however, this work does not fully investigate the challenges of implementing such a technique on a real-world UGV platform, not does it provide experimental testing and results of this technique operating on a moving UGV in typical outdoor terrains. This paper will develop metrics for determining the required point density of the point cloud for calculating the terrain roughness for the technique developed in [27].…”

“…The work in [26] and [27] provides the theoretical basis for this terrain identification technique; however, this work does not fully investigate the challenges of implementing such a technique on a real-world UGV platform, not does it provide experimental testing and results of this technique operating on a moving UGV in typical outdoor terrains. This paper will develop metrics for determining the required point density of the point cloud for calculating the terrain roughness for the technique developed in [27]. Specifically this work will contribute a novel measure of determining the minimum number of points from a point cloud for calculating an effective roughness identification, an experimental method of selecting an appropriate grid cell size based on this minimum point threshold, and (for the first time) realworld experimental testing of this roughness identification method on a UGV travelling under field conditions in typical rough outdoor terrains.…”

Design and Implementation of Navigation Control System for Unmanned Ground Vehicles

“…In addition to, a detailed description of the development of unmanned technology. G. Wilson, et al [6] designed three prediction models for calculating maximum allowable velocity of UGV for traveling on rough unknown terrain. J. Lee, [7] designed a remote control station and its software architecture for efficient control of UGV in combat fields.…”