This paper introduces RHex, a power autonomous, untethered, compliant-legged hexapod robot designed for robust and reliable operation in real-world tasks. RHex features only six actuators, each located at a hip joint, achieving mechanical simplicity and promoting reliable performance. The robot's locomotion is driven by a simple clock-driven, open-loop tripod gait, allowing it to rotate its legs fully in circles and prevent toe stubbing during the protraction phase. Experimental results demonstrate RHex's significant "intrinsic mobility," enabling it to traverse rugged, broken, and obstacle-ridden terrain without terrain sensing or active adaptation. RHex can achieve fast and robust forward locomotion at speeds up to one body length per second and navigate height variations exceeding its body clearance. The design emphasizes mechanical simplicity and autonomy, with limited actuation and reliance on sensing. The control strategy is based on a four-parameter family of controllers that enable translation and turning on flat terrain without explicit enforcement of quasi-static stability. The paper also presents simulation studies and experimental results, showing RHex's ability to move over various terrains, including rough surfaces and obstacles, with high speed and efficiency. The robot's performance is evaluated through specific resistance measurements, and its endurance is tested in standby and walking modes. The authors conclude by discussing the potential for further improvements in RHex's performance by applying biomimetic principles and developing more sophisticated control strategies.This paper introduces RHex, a power autonomous, untethered, compliant-legged hexapod robot designed for robust and reliable operation in real-world tasks. RHex features only six actuators, each located at a hip joint, achieving mechanical simplicity and promoting reliable performance. The robot's locomotion is driven by a simple clock-driven, open-loop tripod gait, allowing it to rotate its legs fully in circles and prevent toe stubbing during the protraction phase. Experimental results demonstrate RHex's significant "intrinsic mobility," enabling it to traverse rugged, broken, and obstacle-ridden terrain without terrain sensing or active adaptation. RHex can achieve fast and robust forward locomotion at speeds up to one body length per second and navigate height variations exceeding its body clearance. The design emphasizes mechanical simplicity and autonomy, with limited actuation and reliance on sensing. The control strategy is based on a four-parameter family of controllers that enable translation and turning on flat terrain without explicit enforcement of quasi-static stability. The paper also presents simulation studies and experimental results, showing RHex's ability to move over various terrains, including rough surfaces and obstacles, with high speed and efficiency. The robot's performance is evaluated through specific resistance measurements, and its endurance is tested in standby and walking modes. The authors conclude by discussing the potential for further improvements in RHex's performance by applying biomimetic principles and developing more sophisticated control strategies.