Slope traversability analysis of reconfigurable planetary rovers

Abstract

Abstract-Future planetary rovers are expected to probe over steep sandy slopes, such as crater rims, where wheel slippage can be a critical issue. One solution to this issue is to mount redundant actuators on the locomotion mechanisms of the rovers such that they can actively reconfigurate themselves to adapt to the driven terrain. In this study, we propose a mechanical model of a rover based on a wheel-soil contact model combined with the classical terramechanic theory. The effects of the rover reconfiguration on its slippage tendencies are analyzed based on slope traversing experiments and numerical simulations. The validation of the proposed contact model is also discussed based on experimental and numerical simulation results. According to the experimental results, both longitudinal and lateral slippages are greatly reduced by tilting the rover in an uphill direction. The results of the numerical simulation match the experimental results quantitatively, and indicate the possible need to include a slope failure model.

Development of multi-D.O.F. tracked vehicle to traverse weak slope and climb up rough slope

“…To reduce this slip, To reduce this slip, Prof. Wettergreen suggested that the posture of the robot should be controlled to remain vertical with respect to gravity [7]. In our research group, we confirmed this suggestion empirically using our wheeled mobile robot and proposed a mechanical model of sideslip based on terramechanics theory [8]. It can be intuitively understood that the horizontal contact configuration shown in Fig.…”

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

“…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. To analyze the effects of reconfiguration over sandy terrain, we extended the conventional terramechanics model to an inclined wheel and applied it to the mechanical model of a reconfigurable rover (Inotsume et al., ). This successfully modeled the relationship between the configuration of a rover and its slippage.…”

High‐speed mobility on planetary surfaces: A technical review

“…Another important limitation in the application of the classical terramechanic model resides in its two‐dimensional representation and the simplification of the wheel geometry. Lateral forces acting on the wheels during certain operations (e.g., steering or slope climbing) are dismissed and, although some authors have extended these models to take into account side forces (Inotsume et al, ; Ishigami et al, ), their effects are often neglected. In addition, planetary robots make use of grousered wheels to facilitate driving over sandy terrains and, recently, flexible metallic wheels are once again becoming the preferred solution (Richter et al, ; Sharma, Tiwary, Kumar, Suresha Kumar, & Keshava Murthy, ).…”

“…These types of passive‐rolling, self‐balancing suspensions have been proven to exhibit great off‐road and obstacle surmounting capabilities but their use and analysis have been limited to a quasistatic framework in which the maximum driving speed considered often does not surpass 10 cm/s. As a result, the quasistatic interaction of this type of robots with sandy, unconsolidated terrains has been widely documented (Ding, Gao, Deng, Nagatani, & Yoshida, ; Inotsume, Sutoh, Nagaoka, Nagatani, & Yoshida, ; Ishigami & Yoshida, ; Ishigami, Miwa, Nagatani, & Yoshida, ; Ishigami, Nagatani, Miwa, & Yoshida, ; Lindemann & Voorhees, ; Oikawa, Yoshida, & Carletti, ). To the extent of the authors’ knowledge, published studies on the performance of planetary robots locomotion subsystems under a dynamic regime are still rather scarce.…”