Balance impairment is critical for many patient groups such as those with neural and musculoskeletal disorders and also the elderly. Accurate and objective assessment of balance performance has led to the development of several indices based on the measurement of the center of pressure. In this study, a robotic device was designed and fabricated to provide controlled and repeatable mechanical perturbations to the standing platform of the user. The device uses servo-controlled actuators and two parallel mechanisms to provide independent rotations in mediolateral and anterior-posterior directions. The device also provides visual feedback of the center of pressure position to the user. Functional tests were run and showed that the device is able to provide an appropriate dynamics (time constant of 0.19 s and bandwidth of 0.85 Hz) for the two motions. The efficacy of the device on the balance assessment was then evaluated experimentally. Ten healthy subjects performed a balance task with and without perturbations and seven center of pressure indices were measured. It was shown that the sensitivity of the indices to the user's performance was statistically increased in all indices particularly in anterior/posterior direction when the mechanical perturbations were present.

平衡障碍对许多患者群体至关重要，例如患有神经和肌肉骨骼疾病的患者以及老年人。对平衡性能的准确和客观的评估导致了一些基于压力中心测量的指标的发展。在这项研究中，设计和制造了一个机器人设备，为用户的站立平台提供可控和可重复的机械扰动。该设备使用伺服控制的执行器和两个平行机构来提供在中间和前后方向的独立旋转。该设备还向用户提供压力中心位置的视觉反馈。运行功能测试并表明该设备能够为两种运动提供适当的动力学（时间常数为 0.19 秒，带宽为 0.85 Hz）。然后通过实验评估该装置对平衡评估的功效。十名健康受试者在有和没有扰动的情况下执行平衡任务，并测量了七个压力中心指数。结果表明，当存在机械扰动时，指标对用户表现的敏感性在所有指标中都有统计学意义的增加，特别是在前/后方向。