Design, Optimization and Energetic Evaluation of an Efficient Fully Powered Ankle-Foot Prosthesis With a Series Elastic Actuator
Design, Optimization and Energetic Evaluation of an Efficient Fully Powered Ankle-Foot Prosthesis With a Series Elastic Actuator
复制标题
具有串联弹性执行器的高效全动力踝足假肢的设计、优化和能量评估
作者：
Dianbiao Dong;W. Ge;Bryan Convens;Yuanxi Sun;T. Verstraten;B. Vanderborght
为膝下截肢者使用动力踝足假体会带来一些挑战，比如所应用的致动器的峰值功率和假足的生物力学特征。提出了一种采用串联弹性作动器的高效动力踝足假体。将齿轮五杆弹簧（GFBS）机构与传统的串联弹性作动器（SEA）相结合，构建了串联弹性齿轮五杆作动器（SGFB）。新的SGFB驱动器具有GFBS和SEA在模仿人类踝关节生物力学和降低电机峰值功率方面的优点。实验结果表明，优化后的SGFB假足（含150W Maxon直流电机）在跑步机试验中可为70kg受试者提供足够的净正能量，能量效率为35.3%。半主动模式下的SGFB假足实验表明，在控制背屈阶段，SGFB假足具有密切模仿人体生物力学的优势，在动力跖屈阶段，注入正能量的重要性。实验结果还表明，考虑到整个传动系统的效率，对机电模型内的不同参数进行优化，可以有效地将电机的峰值功率降低到132 W，使电机在大功率条件下更有效。
The use of powered ankle-foot prostheses for below-knee amputees leads to challenges like the peak power of the applied actuator and biomechanical features of the prosthesis foot. This paper proposes an efficient powered ankle-foot prosthesis with a series elastic actuator. By combining the geared five-bar spring (GFBS) mechanism and the traditional series elastic actuator (SEA), a series elastic with geared five-bar (SGFB) actuator is built. The new SGFB actuator has the benefits of both the GFBS and the SEA on mimicking biomechanics of the human ankle and reducing the peak power of the motor. The healthy walking gait in the experiment results indicates that the optimized SGFB prosthesis foot including a 150W Maxon DC motor can provide a 70kg subject enough net positive energy with an energy efficiency of 35.3% during normal speed walking in the treadmill trials. The experiment of the SGFB prosthesis foot in semi-active mode shows the advantage on closely mimicking the human biomechanics during the control dorsiflexion phase and the importance of injecting positive energy during the powered plantarflexion phase. The experiment results also show that the optimization of different parameters within the electromechanical model considering the efficiency of the whole drive train can effectively reduce the motor’s peak power to 132 W by making the motor more effective in high-power conditions.