Accurate estimation of drawbar pull of wheeled mobile robots traversing sandy terrain using built-in force sensor array wheel

Abstract

Abstract-The wheels of planetary rovers that are used in space explorations sometimes slip or lose contact with the ground while traversing a sandy terrain. In order to estimate the behavior of these rovers moving on loose soil, it is very important to accurately estimate the drawbar pull of their wheels. Some wheel-soil interaction models based on terramechanics have been proposed for the estimation of the normal stress distribution and drawbar pull of such rovers. However, our experimental results (normal stress distributions are directly measured using a pressure sensor array, which is attached to the wheels of a rover) show that the distribution range of normal stress for small wheeled rovers obtained using the proposed method is considerably smaller than that obtained by using conventional method. Consequently, the drawbar pull estimated using conventional methods is inaccurate. Therefore, in this study, the normal stress distribution is directly measured using pressure sensors in order to estimate drawbar pull accurately. From the data obtained using the sensors, a soil parameter, which is generally very difficult to measure, is estimated. Then, the drawbar pull is estimated using this parameter. The drawbar pull estimated by using the proposed method is more accurate than that estimated using conventional methods. In this study, we propose a new method for the estimation of drawbar pull and also validate this method.

Investigation into use of piezoelectric sensors in a wheeled robot tire for surface characterization

“…Nagatani et al [44] used a 12 kg robot equipped with four rigid wheels with grousers. The wheels had normal force sensors embedded on the outside of the tires.…”

Modeling, Analysis, and Control of an Actively Reconfigurable Planetary Rover for Traversing Slopes Covered with Loose Soil

“…Wheel‐soil interactions have been studied in the field of “terramechanics” (Bekker, ; Wong, ), and terramechanics theory has recently been applied to mobility problems in planetary rovers: modeling and traveling ability studies (Bauer et al., ; Krenn and Hirzinger, ; Trease et al., ), terrain parameter estimation (Iagnemma et al., ; Lite et al., ), and terrain classification and its application to the prediction of traveling ability (Brooks and Iagnemma, ). Our research group has also been analyzing the mobility of planetary rovers based on terramechanics and applying terramechanics theory to motion control (Ishigami et al., , ; Nagatani et al., ; Yoshida and Hamano, ). However, terramechanics theory has mainly been applied to wheels that make vertical contact with the soil, and not to a mobility analysis of reconfigurable rovers with wheels that are able to make sidling contact with the soil.…”

Slope traversability analysis of reconfigurable planetary rovers

“…Our research group has also been studying mobility of planetary rovers based on terramechanics [10]- [12]. Nonetheless, the terramechanical theory has mainly been applied to wheels making vertical contact with the soil and not to a mobility analysis of reconfigurable rovers whose wheels can make sidling contact with the soil.…”