Development of a Bio-Inspired Hopping Leg for Lunar Exploration Rover

The goal of this project is to develop and build a jumping robotic leg to be mounted in a rover for lunar terrain exploration. As we may know that most rovers are using wheels for locomotion, the purpose of replacing the wheels with a jumping robotic leg in this project is to enhance the ability of rovers to travel further distances in a shorter time. The improved speed and distance will make lunar missions more efficient on resources and time. The leg design also helps prevent a rover from getting stuck on the exploration due to geographic obstacles such as mountains, canyons, and other miscellaneous terrains. While this idea is not new, this project attempted to create a unique design using the biomechanics of a kangaroo leg to improve jump capabilities such as height and speed. It is expected that a kangaroo-inspired rover model offers a faster speed and better locomotive capacity in the low gravitational environment and allows the rover to navigate the rough lunar terrain more efficiently in comparison to a wheeled rover. Three student teams have been working on this project in different academic years. This year’s team focuses on improving jumping height through energy conservation and reduction of weight. The new three-link leg spring mechanism model is designed, built, and tested. The hop is generated by an actuation system that includes three springs and a pull cable. In the design phase, a CAD model was created, and the jumping leg’s static analysis and dynamic simulation were conducted. The jumping heights were calculated and compared with theoretical calculation and simulation. The conservation of energy law was applied to solve the jump height for the theoretical calculation. In the dynamic simulation, the jump height was measured and recorded by adjusting several leg parameters. The jump heights from the calculation and dynamic simulation were compared. The optimum design of the leg, therefore, was determined to achieve the best jumping height. This paper will discuss the process of this year’s senior team to develop this bio-inspired hopping rover for lunar exploration. The leg prototype was built and made of ABS plastic, and it stands 50 cm high with a weight of 1.56 kg. A testing rig was also developed to measure the leg’s jumping height. This bio-inspired rover could pave the way for improved mobility in unknown, rugged terrains and low gravity environments by overcoming the limitations of the wheeled rovers altogether. This model could lead to the pioneering of using the flexibility of locomotion and miniaturization for lunar exploration.