Small obstacles on the ground often lead to a fall when caught with commercial prosthetic feet. Despite some recently developed feet can actively control the ankle angle, for instance over slopes, their flat and rigid sole remains a cause of instability on uneven grounds. Soft robotic feet were recently proposed to tackle that issue; however, they lack consistent experimental validation. Therefore, this paper describes the experimental setup realized to test soft and rigid prosthetic feet with lower-limb prosthetic users. It includes a wooden walkway and differently shaped obstacles. It was preliminary validated with an able-bodied subject, the same subject walking on commercial prostheses through modified walking boots, and with a prosthetic user. They performed walking firstly on even ground, and secondly on even ground stepping on one of the obstacles. Results in terms of vertical ground reaction force and knee moments in both the sagittal and frontal planes show how the poor performance of commonly used prostheses is exacerbated in case of obstacles. The prosthetic user, indeed, noticeably relies on the sound leg to compensate for the stiff and unstable interaction of the prosthetic limb with the obstacle. Therefore, since the limitations of non-adaptive prosthetic feet in obstacle-dealing emerge from the experiments, as expected, this study justifies the use of the setup for investigating the performance of soft feet on uneven grounds and obstacle negotiation.

翻译：地面上的微小障碍物常导致使用商用假肢足部时发生跌倒。尽管近年来开发的某些假肢足部能主动控制踝关节角度（例如在斜坡上），但其扁平僵硬的鞋底在不平整地面上仍会导致失稳。软体机器人假肢足部近期被提出以解决该问题，但缺乏一致的实验验证。为此，本文描述了为测试下肢假肢使用者佩戴软体和刚性假肢足部所搭建的实验装置，包括木质步道和不同形状的障碍物。该装置经一名健全受试者（通过改良行走靴穿戴商用假肢行走）及一名假肢使用者进行了初步验证。受试者首先在平坦地面行走，随后在平坦地面踩踏障碍物行走。矢状面和冠状面上的垂直地面反作用力和膝关节力矩结果表明，商用假肢的较差性能在障碍物情况下被加剧。事实上，假肢使用者显著依赖健侧腿补偿假肢侧与障碍物之间僵硬且不稳定的交互作用。由于非自适应假肢足部在障碍处理中的局限性如预期般从实验中显现，本研究为利用该装置探究软体假肢足部在不平整地面上的性能及避障能力提供了合理性依据。