Force sensorless compliance control of a lower-limb exoskeleton robot

Chung Hsien Kuo*, Andika Pramanta Yudha, Suvendu Kumar Mohapatra

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

3 Scopus citations


Lower limb rehabilitation machines are widely used to enhance the mobility function of elderly people and patients suffering from spinal cord injury and stroke. In this paper, a four degrees of freedom (DOF) lower body exoskeleton with a model-based compensation control framework is proposed to support hip-knee rehabilitation. The exoskeleton control movement is realized by designing a trajectory for each leg movement. A function approximation technique (FAT) based adaptive control is applied to each two DOF legs during a rehabilitation task. Using the FAT based adaptive control, the natural system dynamic is adaptively compensated for without knowing the acceleration feedback and system dynamics. Simulation results show the disturbance observer successfully estimated the user's applied leg force. The leg force is given as the input to compliance control applied in 2 DOF motors when performing a walking sequence on a treadmill. Moreover, the FAT-based adaptive control outperformed the standard proportional-differential (PD) control and could accommodate different subjects without any changes to control parameters.

Original languageEnglish
Pages (from-to)51-60
Number of pages10
JournalInternational Journal of Automation and Smart Technology
Issue number1
StatePublished - 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 International Journal of Automation and Smart Technology.


  • Disturbance observer
  • Exoskeleton rehabilitation
  • FAT based adaptive control
  • Locomotors training
  • Rehabilitation robots


Dive into the research topics of 'Force sensorless compliance control of a lower-limb exoskeleton robot'. Together they form a unique fingerprint.

Cite this