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 with 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 centre of mass motion, and variabilities in step width, step length and step time were unchanged. We conclude that reducing ankle torque variability of the affected limb is not sufficient for reducing the overall effect of disturbances due to uneven terrain. It is possible that other factors, such as changes in step height or disturbances to the intact limb, play a larger role in difficulty balancing while walking over uneven surfaces.

下肢截肢的个人中有超过一半的人无法在崎terrain的地形上行走。通过使用假体仿真器系统，我们开发了一种消除不规则性的控制器，旨在减少因表面不平整而造成的干扰的影响。该控制器通过响应于当地地形高度来改变两个前掌数字的中性角而起作用。为了隔离控制器的影响，我们还编程了一个类似弹簧的控制器，该控制器保持固定的中性角。五名行胫骨截肢的参与者在跑步机上行走，行走表面不平坦。与类似弹簧的控制器相比，取消不规则的控制器在矢状面和前额面将踝部扭矩的变化性降低了41％，将其降低了64％。但是，与平衡相关的用户结果大多不受影响；仅降低了躯干运动的可变性，而代谢率，中外侧质心运动以及步长，步长和步长的变化均未改变。我们得出的结论是，减少患肢的踝关节扭矩变化性不足以减少由于地形不平坦而造成的整体干扰。在不平坦的地面上行走时，其他因素（例如步高变化或对完整肢体的干扰）可能会在平衡难度方面发挥更大的作用。