Exploring Mars is beneficial to increasing our knowledge, understanding the possibility of ancient microbial life there, and discovering new resources beyond the Earth to prepare for future human missions to Mars. To assist ambitious uncrewed missions to Mars, specific types of planetary rovers have been developed for performing tasks on Mars’ surface. Due to the fact that the surface is composed of granular soils and rocks of various sizes, contemporary rovers can have difficulties in moving on soft soils and climbing over rocks. To overcome such difficulties, this research develops a quadruped creeping robot inspired by the locomotion characteristics of the desert lizard. This biomimetic robot features a flexible spine, which allows swinging movements during locomotion. The leg structure utilizes a four-linkage mechanism, which ensures a steady lifting motion. The foot consists of an active ankle and a round pad with four flexible toes that are effective in grasping soils and rocks. To determine robot motions, kinematic models relating to foot, leg, and spine are established. Moreover, the coordinated motions between the trunk spine and leg are numerically verified. In addition, the mobility on granular soils and rocky surface are experimentally demonstrated, which can imply that this biomimetic robot is suitable for Mars surface terrains.

To increase the knowledge and exploit new resources beyond the Earth, planetary surface exploration on the Moon or Mars attracts significant attention around the globe. Due to the fact that these planetary surfaces are widely covered by soil-like materials, various structures of planetary rovers have been proposed to adapt to the terrains. Nonetheless, the traditional rover structures, such as wheeled and leg-wheeled, have shown limitations in moving on granular soils. To improve the mobility, this paper proposes a multi-toe quadruped robot inspired by the desert chameleon animal. The key features are that each bionic foot possesses four toes to stabilize them on granular materials. Moreover, a bionic flexible spine is designed to coordinate with walking and turning gaits and to make the robot approach an animal-like mobility. To assess the robot performances, kinematics analysis and analytical modeling of foot, leg, and spine movements are carried out. The results demonstrate that this robot can effectively walk and turn in accordance with the adopted gaits. Finally, field tests of moving over sands have been conducted. It shows that the robot can stably walk and turn on sands, which indicates that it is adaptable to planetary granular terrains.