[
    {
        "id": "osp-26787",
        "type": "article-journal",
        "title": "Learning to Exploit Passive Dynamics for Energy-Efficient Target Hopping of a Spring-Legged Quadcopter",
        "author": [
            {
                "family": "Chen",
                "given": "Ruigang"
            },
            {
                "family": "Zhang",
                "given": "Qi"
            },
            {
                "family": "Zhong",
                "given": "Zhicheng"
            },
            {
                "family": "Yun",
                "given": "Zhuorui"
            },
            {
                "family": "Or",
                "given": "Yizhar"
            },
            {
                "family": "Liu",
                "given": "Mingyi"
            }
        ],
        "URL": "https://omanscience.com/ar/articles/learning-to-exploit-passive-dynamics-for-energy-efficient-target-hopping-of-a-spring-legged-quadcopter",
        "language": "en",
        "issued": {
            "date-parts": [
                [
                    2026
                ]
            ]
        },
        "abstract": "Combining aerial thrust with spring-loaded hopping makes monopedal quadcopters promising for locomotion over complex terrain, but heuristic proportional-integral-derivative (PID) tuning limits coordination between active thrust and passive contact dynamics. We present a direct estimated-state-to-motor Proximal Policy Optimization (PPO) policy that commands four motors without an explicit hopping state machine or low-level attitude PID. Its reward combines Energy-Manifold Shaping for mass-normalized vertical-energy tracking and apex-state anchoring with Efficiency Shaping, which uses a history-aware power estimator to penalize general power use, impose an additional airborne-power cost, and penalize airborne near-stationarity. In representative hardware runs, the PPO-based control stack reduced cycle-averaged measured electrical power by 30.7% and mean total normalized thrust by 49.8% relative to the tuned PID-based control stack, while retaining repeatable commanded-height hopping and more concentrated landings. These observations are consistent with improved use of passive dynamics and reduced measured electrical demand."
    }
]