Adaptive Knee Orthosis with Power Support to assist the Elderly

该合作研究项目的目的是为开发具有动力支持的适应性膝关节矫形器提供科学知识，以缓解老年人的行动不便。传统的固定支撑，如升降椅和楼梯升降机，一旦有了升降和爬楼梯的辅助装置，就会变得过时，这种辅助装置可以很容易地应用在身体上，使用舒适，操作直观。对支持需求的独立识别是主动矫形器适应性的特征。这种机电辅助系统可以支持老年人的行动能力。此外，治疗用途是可以想象的。在第一阶段的研究中，开发了连续弹性致动器（SEA）和专用运动学来跟踪膝关节的生理运动，并构建了测试矫形器。通过表面肌电图证实，在转移运动过程中，在外力支持下，膝关节伸肌的激活相应减少。因此，当使用者从坐姿站起来时，矫形器实际上减轻了使用者的负担。坐到站过程的自主控制是通过使用矫形器的用户模型和矫形器脚踏板处的力测量作为输入变量来实现的。这使得用户感知的矫形器的功率和透明度都可以动态缩放。为了实现态势感知，在大腿周围设计了一个机械肌肉活动传感器。惯性传感器提供了矫形器的冗余方向确定，增强了未来的态势感知。目前的演示器仍然相当大，系统由许多外部设备控制，因此难以进行面向实践的测试。在第二个研究阶段，仿生启发分布式弦致动器的开发，使重量和空间显著减少。与运动学和传感器类似，它们将尽可能多地集成在矫形器的框架中。这个现场测试演示者应该接受进一步科学问题的密集测试，例如膝关节运动支持下生物力学负荷的再分配。检查矫形器可能引起的绊倒和跌倒风险。研究结果将在未来用作开发增强移动能力的辅助系统的基础。

The aim of this cooperative research project is to develop scientific knowledge for the development of an adaptive knee orthosis with power support to ease mobility for the elderly. Conventional stationary supports such as rising chairs and stair lifts may become obsolete once an uprising and stair climbing aid is available which is easily applied at the body, comfortable in use and intuitive to operate. The independent recognition of support demand characterizes the adaptive nature of the active orthosis. This kind of mechatronic assistance system could support the elderly in their mobility. Furthermore, therapeutic use is conceivable.In the first phase of research, a serial-elastic actuator (SEA) and special kinematics have been developed to follow the physiological knee motion and test orthoses were built. By means of surface electromyography it was verified that under external power support during the transfer movement, the activation of the knee extensors is reduced accordingly. Hence, the orthosis actually relieves the user when standing up from a sitting position. The autonomous control of the sit-to-stand process is implemented using a model of the user with orthosis and force measurement at the foot-plate of the orthosis as input variable. This allows both, the power and the transparency of the orthosis perceived by the user to be scaled dynamically. For situational awareness, a mechanical muscle activity sensor is designed for use around the thigh. Inertial sensors provide redundant orientation determination of the orthosis and enhance situational awareness in the future.The current demonstrator is still rather large and the system is controlled by a number of external devices, so that a practice-oriented testing is difficult. In the second research phase, bionically inspired distributed string-actuators are developed that allow significant weight and space reduction. Similar to the kinematics and sensors, they will be integrated in the framework of the orthosis as much as possible. This field test demonstrator should then be subject of intensive tests for further scientific issues such as the redistribution of biomechanical loads under motor support at the knee. Possible tripping and falling risks induced by the orthosis are examined. The results will be used in the future as a basis for the development of mobility-enhancing assistance systems.