A series elastic actuator (SEA) using an ultrasonic motor (USM) and an elastic element has attracted attention as a compact actuator with high torque–weight ratio and high force control performance. However, an elastic element in a SEA often causes mechanical vibrations. To suppress these vibrations, studies implemented the state feedback of the motor‐ and load‐side angles. However, as the controller has many integrators, the control system becomes unstable when the angular‐velocity of the USM is saturated. Therefore, in this study, integrators in the controller were reduced in number. Furthermore, a limit error feedback controller was designed to suppress the windup phenomenon caused by the integrators. The frequency analysis using a describing function showed that stability is guaranteed even if the angular‐velocity is saturated. In addition, the experimental results indicate that an overshoot of the torque response is suppressed.

中文翻译：

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使用具有角速度饱和的超声波马达对串联弹性执行器进行扭矩控制

使用超声波马达（USM）和弹性元件的串联弹性执行器（SEA）作为具有高扭矩重量比和高力控制性能的紧凑型执行器而备受关注。但是，SEA中的弹性元件通常会引起机械振动。为了抑制这些振动，研究实施了电机和负载侧角度的状态反馈。但是，由于控制器具有许多积分器，因此当USM的角速度达到饱和时，控制系统变得不稳定。因此，在这项研究中，控制器中的积分器数量减少了。此外，设计了极限误差反馈控制器来抑制积分器引起的缠绕现象。使用描述函数的频率分析表明，即使角速度达到饱和，也可以保证稳定性。此外，