发表机构
Iowa State University（爱荷华州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文针对类人机器人投掷美式橄榄球的自旋控制问题，提出耦合全身控制策略，在宇树G1机器人上实现高自旋效率的紧密螺旋投掷，达到93.6%自旋效率等性能。
AI 中文摘要
精准投掷美式橄榄球需要精确控制释放条件，其中耦合的线动量与角动量决定飞行稳定性和瞄准精度。此前机器人投掷物体的研究大多聚焦于采用开式夹具范式生成动态可行的释放速度，而对分离时的自旋注入的明确控制仍探索不足，尤其针对美式橄榄球这类空气动力学各向异性的物体。本文提出类人机器人实现美式橄榄球的自旋稳定受控紧密螺旋投掷，要达成这一目标需满足两点：一是精准达到所需的耦合动量，这通常需要在约半秒内完成多自由度（DoF）运动；二是管理100毫秒以内释放阶段产生的复杂瞬态接触动力学，此时橄榄球在手指间部分移动，本质上处于欠驱动状态。为此，我们开发了一种耦合全身控制策略，其中下肢执行智能稳定，而上身进一步分为两个阶段：（i）投掷阶段，通过轨迹优化与跟踪将橄榄球加速至目标状态；（ii）随挥阶段，利用模型预测控制主动控制手腕及剩余接触的手指。所提框架在29自由度的宇树G1（Unitree G1）类人机器人上得到实证验证，该机器人配备7自由度的Dex3-1三指夹具。被投掷的美式橄榄球在最高5.35米/秒的线速度、14.5弧度/秒的角速度下，达到93.6%的自旋效率和0.286弧度的线速度-鼻端对准（鼻角）误差（其中“理想”紧密螺旋对应100%的自旋效率和0弧度的鼻角误差）。
英文摘要
Accurate throwing of the American football requires precise regulation of release conditions, where coupled linear and angular momentum determine flight stability and targeting accuracy. While prior work on robotic object throwing has largely focused on generating dynamically feasible release velocities using open-gripper paradigms, explicit control of spin injection at detachment remains underexplored, particularly for aerodynamically anisotropic objects like the American football. In this paper, we present the spin-stabilized controlled tight spiral throw of an American football by a humanoid robot. Achieving this requires (i) accurately reaching the desired coupled momentum, which often involves high degrees-of-freedom (DoF) movements completed within approximately half a second, and (ii) managing the complex transient contact dynamics that arise during the sub-100-millisecond release phase, when the football is effectively underactuated as it moves partially across the fingers. To this end, we develop a coupled whole-body control strategy where the lower body is performing informed stabilization while the upper body is further divided into two phases with (i) a throw phase accelerating the football to a target state through trajectory optimization and tracking, and (ii) a follow-through phase utilizing model predictive control to actively control the wrist and remaining in-contact fingers. The proposed framework is empirically validated on a 29-DoF Unitree G1 humanoid equipped with a 7-DoF Dex3-1 three-fingered gripper. The thrown American football reaches up to 93.6% spin efficiency and a 0.286 radians linear-velocity-to-nose-alignment (nose-angle) error (where an ``ideal'' tight spiral corresponds to 100 % spin efficiency and 0 radians nose-angle error) at up to a 5.35 m/s linear velocity and an angular velocity of 14.5 rad/s.
