A torque-ripple compensation scheme for harmonic drive systems

Yu-Shen Lu, Shuan Min Lin, Markus Hauschild, Gerd Hirzinger

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


This paper presents a scheme for controlling the output torque of a harmonic drive actuator equipped with a torque sensor. The proposed control is composed of a feedback control and a feedforward learning control, in which the feedback control shapes nominal system dynamics using the internal model control structure. The feedforward learning controller employs a disturbance observer (DOB) to evaluate compensation error of the feedforward control for the learning, so as to compensate for torque ripples induced by harmonic drives. Robust stability conditions of the proposed DOB-based learning control system are provided. Experimental results show the effectiveness of the proposed scheme in alleviating the major component of torque ripples whose frequency is twice the angular frequency of the input shaft.

Original languageEnglish
Pages (from-to)357-365
Number of pages9
JournalElectrical Engineering
Issue number4
Publication statusPublished - 2013 Dec 1


  • Disturbance observer
  • Harmonic drive actuator
  • Repetitive learning control
  • Torque control
  • Torque ripple

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Applied Mathematics


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