The effects of ground-irregularity-cancelling prosthesis control on balance over uneven surfaces

Over half of individuals with a lower-limb amputation are unable to walk on uneven terrain. Using a prosthesis emulator system, we developed an irregularity-cancelling controller intended to reduce the effect of disturbances resulting from uneven surfaces. This controller functions by changing the neutral angles of two forefoot digits in response to local terrain heights. To isolate the effects of the controller, we also programmed a spring-like controller that maintained fixed neutral angles. Five participants with transtibial amputation walked on a treadmill with an uneven walking surface. Compared to the spring-like controller, the irregularity-cancelling controller reduced ankle torque variability by 41% in the sagittal plane and 64% in the frontal plane. However, user outcomes associated with balance were mostly unaffected; only trunk movement variability was reduced, whereas metabolic rate, mediolateral center of mass motion, and variabilities in step width, step length, and step ...超过半数的下肢截肢受试者无法在不平坦地形上行走。本研究采用假肢仿真系统（prosthesis emulator system），开发了一款不规则地形抵消控制器（irregularity-cancelling controller），旨在削弱不平坦地形所引发的干扰效应。该控制器通过响应局部地形高度，调整两枚前足趾的中立角以实现工作功能。为单独验证该控制器的作用效果，本研究同时编写了一款维持固定中立角的类弹簧控制器。5名经胫骨截肢（transtibial amputation）受试者在带有不平行走表面的跑台上完成了行走试验。与类弹簧控制器相比，不规则地形抵消控制器可使踝关节力矩变异性在矢状面降低41%，在冠状面（frontal plane）降低64%。但与平衡相关的受试者指标大多未受显著影响；仅躯干运动变异性有所降低，而代谢率、左右方向质心运动以及步宽、步长和步...的变异性均未出现明显变化。