Motion control of passive intelligent walker using servo brakes

Yasuhisa Hirata, Asami Hara, Kazuhiro Kosuge

Research output: Contribution to journalArticlepeer-review

173 Citations (Scopus)


We propose a new intelligent walker based on passive robotics that assists the elderly, handicapped people, and the blind who have difficulty in walking. We developed a prototype of the Robot Technology Walker (RT Walker), a passive intelligent walker that uses servo brakes. The RT Walker consists of a support frame, two casters, two wheels equipped with servo brakes, and it has passive dynamics that change with respect to applied force/moment. This system is intrinsically safe for humans, as it cannot move unintentionally, i.e., it has no driving actuators. In addition, the RT Walker provides a number of navigational features, including good maneuverability, by appropriately controlling the torque of servo brakes based on RT. We propose a human adaptive motion control algorithm that changes the apparent dynamics to adapt to user difficulties, and an environmentally adaptive motion control algorithm, which incorporates environmental information to provide obstacle/step avoidance and gravity compensation functions. The proposed control algorithms are experimentally applied to the RT Walker to test their validity.

Original languageEnglish
Pages (from-to)981-990
Number of pages10
JournalIEEE Transactions on Robotics
Issue number5
Publication statusPublished - 2007 Oct


  • Brake control
  • Intelligent walker
  • Passive robotics
  • Physical interaction
  • Robot technologies (RTs)


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