Field Usability Testing of a robotic wheelchair with passive-active suspension for seat stability in uneven terrains

目前，现有的电动轮椅（EPWs）主要限于在室内使用 和户外的ADA兼容表面。EPW使用者经常接触不规则的表面 其包括倾斜表面（即，斜坡和路缘坡道）和/或地面变化的表面 （一）e.人行道、路缘斜坡、减速带、鹅卵石）。试图在这样的表面上开车 由于轮椅的局限性和使用者有限的空间意识，可能导致稳定性的丧失。 此外，具有建筑障碍物的表面，例如被阻挡的路边坡道或处于不良状况的表面， 限制轮椅使用者进入人行道，限制他们参与社区活动。 移动增强机器人（MEBot）EPW的开发旨在降低尖端和 面对这些具有挑战性的地形时，通过先进的移动应用福尔斯。期间 CDA-1，MEBot重新设计了被动主动驱动和悬挂（MEBot-PAAS） 系统提供更快和可靠的反应，以保持稳定的倾斜表面（格兰特 #A3076-M）与市售EPW及其先前版本相比。虽然稳定性 成功，有人指出，其座位方向显着改变，在突然变化， 表面上在地面变化较大的路面上驾驶（例如，人行道裂缝，路缘 滴、坑）可能导致MEBot-PAAS翻转。因此，本CDA-2建议目标1） 实施MEBot-PAAS能力，以穿越不规则表面（CDA-1中未涉及） 同时保持稳定。此外，目标2）将通过以下方式确定其特征和临床使用限制： 利益攸关方群体。目标3）将评估MEBot-PAAS在退伍军人中的可用性， 残疾人在现实世界中的环境，以实现技术准备，把它给退伍军人。 目标1（1-2年）：MEBot-PAAS应用的实施和评估（自调平和 步骤协商）以在不规则表面上导航。目标将分三个阶段进行： 第1阶段：执行MEBot-PAAS应用程序实施的工程变更： ·开发动态模型以减少压力中心位移并保持稳定性 ·结合深度传感器，用于表面表征和表面前方的速度限制。 ·实现腿轮运动，以导航具有显著地面变化的表面。 第2阶段：工程分析将使用 受控不规则表面上的“救援假人”，以满足第1阶段的设计标准。 第3阶段：评估MEBot-PASS与MEBot-nPAAS相比的性能（应用 停用）在受控的不规则表面上。MEBot-nPAAS将模拟传统的EPWs。 我们假设：H1 A。MEBot-PAAS将显示更少的压力中心位移和H1b。 座椅角度变化小于MEBot-nPAAS。H1c。振动水平的显著差异将 在MEBots之间进行观察。此外，参与者将报告H1 d。更小的倾斜幅度，H1 e。更高 与MEBot-nPAAS相比，MEBot-PAAS的可用性和更低的不适评分。 目标2（第3年）。根据临床使用限制确定MEBot-PAAS的益处和局限性 工具（法规判例法）。这些工具包括轮椅标准和利益攸关方的反馈。 目标3（第4年）。MEBot-PAAS在户外环境中的现场可用性评估。我们 假设H3 a。MEBot-PAAS将显示更少的座椅角度变化和振动水平， 与参与者自己的EPWs进行比较。H3b。参与者将报告显着减少精益 振幅（安全感知），更高的可用性，更少的不适，以及更低的任务负荷需求， 使用MEBot-PAAS与他们自己的EPWs进行比较

At present, existing Electric Powered Wheelchairs (EPWs) are limited primarily to use indoors and outdoors with ADA compliant surfaces. EPW users are often exposed to irregular surfaces that include inclined surface (i.e., slopes and, curb-ramps) and/or surfaces with ground changes (i. e. sidewalks, curb drops, speed-bumps, cobblestones). Attempting to drive over such surfaces may cause loss of stability due to wheelchair limitations and user’s limited spatial awareness. Further, surfaces with architectural barriers such as blocked curb-ramps or in bad condition may constrain wheelchair user from accessing sidewalks, limiting their participation in the community. The Mobility Enhancement Robotic (MEBot) EPW was developed to reduce the risk of tips and falls when facing these challenging terrains through advanced mobility applications. During the CDA-1, MEBot was re-designed with a passive-active actuation and suspension (MEBot-PAAS) system to offer a faster and reliable response to maintain stability on inclined surfaces (Grant #A3076-M) compared to commercial EPWs and its previous iteration. While stability was successful, it was noted that its seat orientation significantly changed during sudden changes in the surface. Driving on surfaces with significant ground changes (e.g., sidewalk cracks, curb drops, potholes) may cause MEBot-PAAS to roll-over. Therefore, this CDA-2 proposes to Aim 1) implement MEBot-PAAS capabilities to traverse irregular surfaces (not addressed in the CDA-1) while maintaining stability. Further, Aim 2) will identify its features and clinical limits of use by a group of stakeholders. Aim 3) will evaluate the usability of MEBot-PAAS with Veterans with disabilities in real-world environments to achieve technology readiness to bring it to Veterans. Aim 1 (Year 1-2): Implementation and evaluation of MEBot-PAAS applications (self-leveling and step negotiation) to navigate on irregular surfaces. Aim will be conducted in three phases: Phase 1: Perform engineering changes for implementation of MEBot-PAAS applications: • Develop a dynamic model to reduce Center of Pressure displacement and maintain stability • Incorporate depth sensors for surface characterization and speed limitation ahead of surfaces. • Implement legged-wheel motion to navigate surfaces with significant ground changes. Phase 2: Engineering analysis will evaluate the implemented MEBot-PAAS applications using a ‘rescue dummy’ on controlled irregular surfaces to meet Phase 1 design criteria. Phase 3: Evaluate the performance of MEBot-PASS compared to MEBot-nPAAS (applications de-activated) on controlled irregular surfaces. MEBot-nPAAS will simulate conventional EPWs. We hypothesize that: H1a. MEBot-PAAS will show less center of pressure displacement and H1b. less seat angle variation than MEBot-nPAAS. H1c. A significant difference in vibration levels will be observed between MEBots. Also, participants will report H1d. less lean amplitude, H1e. higher usability and less discomfort scores with MEBot-PAAS compared to MEBot-nPAAS. Aim 2 (Year 3). Identify MEBot-PAAS benefits and limitations following the Clinical Limits of Use Tools (CLOUT). These tools include wheelchair standards and stakeholders’ feedback. Aim 3 (Year 4). Field usability evaluation of MEBot-PAAS in outdoor environments. We hypothesize that H3a. MEBot-PAAS will show less seat angle variation and vibration levels in comparison to participants’ own EPWs. H3b. Participants will report significantly less lean amplitude (safety perception), higher usability, less discomfort, and lower task load demand when using MEBot-PAAS in comparison to their own EPWs