This work presents methods for the seamless execution of arbitrary spherical trajectories with a seven-degree-of-freedom robotic arm as a sample holder. The sample holder is integrated into an existing X-ray computed tomography setup. We optimized the path planning and robot control algorithms for the seamless execution of spherical trajectories. A precision-manufactured sample holder part is attached to the robotic arm for the calibration procedure. Different designs of this part are tested and compared to each other for optimal coverage of trajectories and reconstruction image quality. We present experimental results with the robotic sample holder where a sample measurement on a spherical trajectory achieves improved reconstruction quality compared to a conventional circular trajectory. Our results demonstrate the superiority of the discussed system as it outperforms single-axis systems by reaching nearly 82\% of all possible rotations. The proposed system is a step towards higher image reconstruction quality in flexible X-ray CT systems. It will enable reduced scan times and radiation dose exposure with task-specific trajectories in the future, as it can capture information from various sample angles.

翻译：本文提出了利用七自由度机械臂作为样品架，无缝执行任意球形轨迹的方法。该样品架被集成到现有X射线计算机断层扫描装置中。我们优化了路径规划与机器人控制算法，以实现球形轨迹的无缝执行。为校准流程，在机械臂上安装了精密加工的样品架部件。通过对比测试不同设计方案，评估其对轨迹覆盖范围及重建图像质量的优化效果。实验结果表明，相较于传统圆形轨迹，采用球形轨迹的样品测量显著提升了重建质量。本系统在可达旋转角度方面达到近82%，展现出超越单轴系统的优越性。该研究为柔性X射线CT系统实现更高图像重建质量奠定了基础，未来可通过任务特异性轨迹从多个样品角度采集信息，从而缩短扫描时间并降低辐射剂量。