Design and Control of a Novel Two Different Stiffness Series Elastic Actuator

新型雙剛度串聯彈性驅動器的設計與控制

尹凱陽(Kai-Yang Yin) ； 向馗(Kui Xiang) ； 陳靜(Jing Chen) ； 龐牧野(Mu-Ye Pang)

《中國機械工程學刊》 40卷6期 (2019/12) Pp. 693-701

摘要

Series elastic actuators (SEA) are desirable for human-centered robotics. However, conventional series elastic actuators face a performance limitation due to the compromise on the elastic element stiffness selection. This paper presents a novel two different stiffness series elastic actuator (DSSEA) and an optimal controller for it to address the performance limitation. In particular, two both stiffness and length are different springs were chosen as the elastic element of the DSSEA. The low stiffness spring single used to deal with the low force operation and the two spring combined used to handle the large force operation. To address the challenge of the smooth transition between those two operation cases, a segmental model-based feedback controller with feedforward compensation is proposed, and a smooth switching controller is designed to handle the transition interval. The experimental results from DSSEA prototype demonstrate that the proposed controller can achieve excellent force tracking performance at both low, high, and wide-bound force range operation.

關鍵字

Series Elastic Actuator ； Segmental control ； Smooth switching control ； Linear quadratic regulator

並列摘要

串聯彈性驅動器被廣泛應用於人機協作機器人，傳統串聯彈性驅動器面臨著由於彈性器件的折中選擇引起的性能限制。本文提出一種新型的雙剛度串聯彈性驅動器並設計配套優化控制演算法，以解決這一性能限制。主要表現為，兩個剛度與長度都不相同的線性彈簧並聯作為彈性器件。在低作用力輸出範圍內，剛度小的彈簧其作用，而在高作用力範圍內，兩個彈簧共同作用。設計一種平滑控制器用於解決在高低作用力區間的平滑切換的問題。實驗結果表明，提出雙剛度串聯彈性驅動器在低作用力區間、高作用力區間、和同時包含高低作用力區間都能達到滿意的力輸出跟蹤性能。