This paper presents the design and control of a ballbot drivetrain that aims to achieve high agility, minimal footprint, and high payload capacity while maintaining dynamic stability. Two hardware platforms and analytical models were developed to test design and control methodologies. The full-scale ballbot prototype (MiaPURE) was constructed using off-the-shelf components and designed to have agility, footprint, and balance similar to that of a walking human. The planar inverted pendulum testbed (PIPTB) was developed as a reduced-order testbed for quick validation of system performance. We then proposed a simple yet robust LQR-PI controller to balance and maneuver the ballbot drivetrain with a heavy payload. This is crucial because the drivetrain is often subject to high stiction due to elastomeric components in the torque transmission system. This controller was first tested in the PIPTB to compare with traditional LQR and cascaded PI-PD controllers, and then implemented in the ballbot drivetrain. The MiaPURE drivetrain was able to carry a payload of 60 kg, achieve a maximum speed of 2.3 m/s, and come to a stop from a speed of 1.4 m/s in 2 seconds in a selected translation direction. Finally, we demonstrated the omnidirectional movement of the ballbot drivetrain in an indoor environment as a payload-carrying robot and a human-riding mobility device. Our experiments demonstrated the feasibility of using the ballbot drivetrain as a universal mobility platform with agile movements, minimal footprint, and high payload capacity using our proposed design and control methodologies.

翻译：本文介绍了一种可在保持动态稳定性的同时实现高灵活性、最小占地面积和高负载能力的球驱机器人传动系统设计与控制。我们开发了两个硬件平台及分析模型以验证设计与控制方法。全尺寸球驱机器人原型(MiaPURE)采用商用组件构建，其灵活性、占地面积和平衡能力与步行人类相当。我们开发了平面倒立摆试验台(PIPTB)作为降阶测试平台，用于快速验证系统性能。随后提出了一种简单而鲁棒的LQR-PI控制器，用于在重负载下平衡并操控球驱机器人传动系统。该控制器至关重要，因为传动系统常因扭矩传输系统中的弹性元件而存在高静摩擦力。该控制器首先在PIPTB上与传统LQR及级联PI-PD控制器进行对比测试，随后在球驱机器人传动系统中实现。MiaPURE传动系统能够承载60千克负载，沿选定平移方向达到2.3米/秒的最大速度，并能从1.4米/秒的速度在2秒内停止。最后，我们演示了球驱机器人传动系统在室内环境中作为载物机器人和人类骑行移动设备的全向运动能力。实验结果表明，采用我们提出的设计与控制方法，可将球驱机器人传动系统用作兼具灵活运动、最小占地面积和高负载能力的通用移动平台。