Abstract: A small and bio-inspired intermittent hopping robot is designed for planetary surface exploration.Based on the fundamentals of metamorphic mechanisms and the force-transforming characteristics of geared linkages containing closed kinematic chains,a kangaroo-inspired hopping mechanism of the robot with controllable link-length and asymmetric geared six-bar linkage is proposed.The intermittent hopping process of the mechanism is analyzed,and the configuration and dimension parameters of the robot are optimally designed for improving the hopping capabilities and the stability of the robot's trunk in take-off phase.Based on the results of optimal design,the dynamic simulation analysis and prototype experiment are implemented.The results show that the bio-inspired hopping robot has such capabilities as nonlinearly increasing driving force,stable jumping posture and high mechanical energy utilization efficiency,and can realize intermittent jumping by using solar energy power and a single micro-motor.