Robots equipped with anchoring mechanisms have attractive applications in asteroid exploration. However, complex application scenarios bring great challenges to the modeling and control of anchoring mechanisms. This paper presents a grasping model and control method for an anchoring mechanism for asteroid exploration. First, the structure of the anchoring mechanism is demonstrated. Second, stochastic grasping models based on surface properties are established. The effectiveness of the grasping model is verified by experiments. A stiffness-modeling method of the microspine is proposed. On this basis, the stochastic grasping model of the anchoring mechanism is established, and the grasping cloud diagram of the anchoring mechanism is drawn. Third, in order to reduce the collision force between the anchor mechanism and the asteroid surface, a control method for the anchoring mechanism in the movement process is proposed based on the motion mode of the asteroid-exploration robot. Finally, a prototype is developed, and the experimental results validate the motion ability of the robot and the control method.

Multi-legged robots with rigid-flexible coupling grippers have appealing applications to asteroid exploration with the microgravity. However, these robots usually have significantly complicated structures, which leads to a great challenge for the kinematic design.This paper proposes the kinematic design method for a novel multi-legged robot with the microspine gripper. First, the structure of the multi-legged asteroid exploration robot and the microspine gripper are demonstrated. Second, four performance evaluation indices, which are used to evaluate the stiffness, velocity, motion / force transfer efficiency and gripper attachment efficiency of the robot, are derived from the kinematic model. Non-dimensional design spaces of parameters to be optimized are drawn, and performance atlases are presented in design spaces. Third, the stiffness model of the microspine is derived. In addition, the constraint condition of the restoring spring is established, and the stiffness of restoring springs are optimized using the genetic algorithm. Several experiments are conducted to verify the stiffness model of the microspine. Finally, the prototype is developed and the experimental results validates the kinematic design method.

Multi-legged climbing robots have appealing applications to extreme terrain on asteroids with the microgravity. The robot usually consists of multiple legs and grippers with hierarchical arrays of microspines. The dimensional optimization of the robot with the complicated structure is still a challenge. This paper proposes a multi-parameter grouping optimization method for the multi- legged climbing robot based on performance atlas. First, the structure of the multi-legged climbing robot is described and the kinematic model is established. Second, four performance evaluation indices of the robot, namely the global conditioning index (GCI), the global stiffness index (GSI), the global transmission index(GTI), and the global adhesion efficiency index (GAEI), are derived from the kinematic equations. Third, 11 dimensional parameters of the robot are catergorized into three groups and the detailed optimization process is poposed. Non-dimensional design spaces of three groups of parameters are established and performance atlases regarding the aforementioned evaluation indices are drawn. Finally, the optimal diemensions of the robot are obtained. Besides, the proposed multi-parameter optimization method can be further applied to other legged robots, and the global adhesion efficiency index can be used to guide the design of other grippers.

No abstract