A serial-type dual actuator unit with planetary gear train: Basic design and applications

Byeong Sang Kim, Jae Bok Song, Jung Jun Park

Research output: Contribution to journalArticlepeer-review

68 Citations (Scopus)


Control of a robot manipulator in contact with the environment is usually conducted by a direct feedback control system using a forcetorque sensor or an indirect impedance control scheme. Although these methods have been successfully applied to many applications, simultaneous control of force and position cannot be achieved. To cope with such problems, this paper proposes a novel design of a dual actuator unit (DAU) composed of two actuators and a planetary gear train to provide the capability of simultaneous control of position and stiffness. Since one actuator controls position and the other actuator modulates stiffness, the DAU can control the position and stiffness simultaneously at the same joint. Both the torque exerted on the joint and the stiffness of the environment can be estimated without an expensive force sensor. Various experiments demonstrate that the DAU can provide good performance for position tracking, force estimation, and environment estimation.

Original languageEnglish
Article number4840358
Pages (from-to)108-116
Number of pages9
JournalIEEE/ASME Transactions on Mechatronics
Issue number1
Publication statusPublished - 2010 Feb

Bibliographical note

Funding Information:
Manuscript received July 26, 2008; revised October 23, 2008. First published April 24, 2009; current version published November 18, 2009. Recommended by Technical Editor O. Kaynak. This work was supported by a Korea Science and Engineering Foundation (KOSEF) Grant funded by the Korean Government (MOST) (R11-2007-028-01002-0).


  • Environment estimation
  • Force estimation
  • Planetary gear train
  • Redundant actuation
  • Variable impedance approach (VIA)

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering


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