Design and analysis of an electro-adhesive hexapod robot with convertible limbs in microgravity

Service space robotics can provide on-orbit maintenance for faulty spacecrafts to extend life and reduce economic losses. In many cases, spacecraft failures are minor and can be easily recovered by completing simple manipulations or by providing observations. In this study, we propose a spacecraft surface adhesion-crawling-manipulation hexapod robot that can provide such services. To avoid increasing the payload, both of the robot’s forelimbs were designed to be convertible, integrating manipulation and locomotion capabilities; the manipulation methods for the novel convertible limb are analyzed. A novel foot trajectory generation method is proposed to reduce the contact force generated when the foot of the robot touches the spacecraft surface and increase dynamic stability. Theoretical and experimental analyses of our robot are presented. Kinematic analyses are performed to validate the manipulation methods using convertible forelimbs. The stability of the robot’s static adherence and dynamic crawling are analyzed in a microgravity simulation environment. A physical ground test is conducted to demonstrate the mobility and manipulation capabilities of the robot.