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Owing to different gravities, the same manned lunar rover shows different acceleration properties on the earth and the moon; therefore, it is of great significance for astronauts to be trained on the earth under the condition of the acceleration properties found on the moon. In this article, a novel acceleration imitation method focused on a single wheel is proposed to obtain equivalent acceleration when using the same acceleration driver input under different gravities, and the acceleration imitation algorithm is derived based on a mechanical model of a special metal wheel with a mesh surface. To reduce the complexity and improve the real-time properties of the algorithm, a fitting function for the imitation torque ratio is proposed to adjust the relationship between the acceleration driver input and the driving torque of the wheel. Finally, experiments were conducted to verify the acceleration imitation algorithm, and the results revealed that the wheel with an imitation torque ratio could effectively approximate on the earth the same acceleration experienced by a single wheel of a manned lunar rover on the moon, given equivalent acceleration driver inputs. [ABSTRACT FROM AUTHOR]

The lunar surface is a complicated and unknown terrain, and hence, astronauts must be trained to travel on that surface by using a prototype vehicle on the Earth's terrain. However, the gravity of the Earth is six times that of the Moon; thus, the acceleration of a prototype vehicle on the Earth will differ from that of a manned lunar rover on the Moon, when the same acceleration handling input is provided. To obtain the same acceleration in the prototype vehicle on the Earth as that obtained on the Moon, an imitation handling ratio describing the relationship between the acceleration handling input and the wheel rolling speed is proposed in order to replicate the lunar gravitational conditions on the Earth. First, a whole-vehicle acceleration model was established based on the mechanical model of a deformable wheel with a mesh surface. Thereby an acceleration imitation algorithm was derived. A prototype vehicle for use on the Earth is proposed for the purpose of imitating the manned lunar rover under four different vehicle conditions. Fitted functions were used in order to obtain the imitation handling ratio. Finally, experiments were conducted to verify the imitation method; the results revealed that the prototype vehicle on the Earth could effectively approximate the same accelerations experienced by a manned lunar rover, when equivalent acceleration handling inputs were provided. [ABSTRACT FROM AUTHOR]

A lunar roving vehicle is of great significance in the processing of manned lunar exploration for long-duration space exploration missions. The mechanical model of the lunar roving vehicle’s wheel directly affects the mobility performance. However, the wheel of lunar roving vehicle is a special one with the metal mesh surface, and the soil can penetrate through its surface. In this paper, the mechanical model of a rigid normal wheel is deduced, and four stress correction coefficients are introduced to obtain the mechanical model of the lunar roving vehicle’s wheel. These four stress correction coefficients are identified in several groups of experiment of the lunar roving vehicle’s wheel, and using the functional coefficients can have a high precision for the mechanical model of the lunar roving vehicle’s wheel. [ABSTRACT FROM AUTHOR]

As an indispensable tool for astronauts on lunar surface, the lunar roving vehicle (LRV) is of great significance for manned lunar exploration. An LRV moves on loose and soft lunar soil, so the mechanical property of its wheels directly affects the mobility performance. The wheels used for LRV have deformable and mesh pattern, therefore, the existing mechanical theory of vehicle wheel cannot be used directly for analyzing the property of LRV wheels. In this paper, a new mechanical model for LRV wheel is proposed. At first, a mechanical model for a rigid normal wheel is presented, which involves in multiple conventional parameters such as vertical load, tangential traction force, lateral force, and slip ratio. Secondly, six equivalent coefficients are introduced to amend the rigid normal wheel model to fit for the wheels with deformable and mesh-pattern in LRV application. Thirdly, the values of the six equivalent coefficients are identified by using experimental data obtained in an LRV’s single wheel testing. Finally, the identified mechanical model for LRV’s wheel with deformable and mesh pattern are further verified and validated by using additional experimental results. [ABSTRACT FROM AUTHOR]

To investigate and improve the mobility of the Lunar Roving Vehicle (LRV), it is necessary to consider the mechanical properties of the interaction between the wheels and the ground. In this paper, a new solution method, the forced-slip solution method, which uses a semi-empirical approach, was presented. That is, given the wheel’s vertical load and drawbar pull or driving torque as known input values, the unknown slip ratio can be resolved. The alternative method involves predicting the mechanics for a given slip ratio. The proposed method correlates better with actual wheel movements, and by studying a single wheel, this solution method can also be used to resolve the mechanical properties of the front and rear wheels in a four-wheel-drive (4WD) LRV configuration. It can also be used to consider the multi-pass effect of the rear wheels on lunar soil. The calculation results show that the 4WD LRV driving efficiency varies with the position of the center of mass. Thus, the LRV driving efficiency can be optimized by adjusting the position of its center of mass. [ABSTRACT FROM AUTHOR]