We present SPARC, a compact, open-source 3-DoF sagittal-plane spine module that combines revolute (pitch) and prismatic (axial) motion with programmable task-space impedance for quadruped robots. The system integrates three torque-controlled actuators, a 1~kHz control board, and protected power electronics in a 1.26~kg package. A floating-base impedance controller with dynamics compensation renders tunable spring-damper behavior along horizontal, vertical, and rotational axes. Benchtop experiments validate the approach: quasi-static tests demonstrate linear force-displacement characteristics with commanded horizontal stiffness spanning 300--700~N/m ($\leq 1.5\%$ error, $R^2 \geq 0.992$), while dynamic trials confirm predictable damping behavior across multiple settings. Furthermore, simulation studies reveal that adapting spine stiffness based on terrain slope and stride length significantly reduces the cost of transport. SPARC provides an open-source platform for systematic studies of spine compliance in legged locomotion, with complete hardware and firmware resources available for community use. Github repository: https://github.com/YueWang996/sparc.git

翻译：本文提出SPARC，一种紧凑、开源的三自由度矢状面脊柱模块，结合了旋转（俯仰）与棱柱（轴向）运动，并为四足机器人提供可编程任务空间阻抗。该系统集成了三个扭矩控制执行器、1千赫兹控制板及受保护的功率电子器件，总重1.26千克。采用带动力学补偿的浮动基阻抗控制器，实现了沿水平、垂直和旋转轴的可调弹簧-阻尼行为。台架实验验证了该方案：准静态测试显示力-位移呈线性特征，水平刚度指令范围300-700牛/米（误差≤1.5%，R²≥0.992）；动态试验则证实了多参数设置下可预测的阻尼行为。此外，仿真研究表明，根据地形坡度和步幅长度自适应调整脊柱刚度可显著降低运输能耗。SPARC为系统研究腿式运动中脊柱柔顺性提供了开源平台，其完整的硬件与固件资源已向社区开放。代码仓库：https://github.com/YueWang996/sparc.git