Multi-DOF counterbalance mechanism for a service robot arm

Hwi Su Kim, Jae Bok Song

Research output: Contribution to journalArticlepeer-review

85 Citations (Scopus)


Low-cost but high-performance robot arms are required for widespread use of service robots. Most robot arms use expensive motors and speed reducers to provide torques sufficient to support the robot mass and payload. If the gravitational torques due to the robot mass, which is usually much greater than the payload, can be compensated for by some means; the robot would need much smaller torques, which can be delivered by cheap actuator modules. To this end, we propose a novel counterbalance mechanism which can completely counterbalance the gravitational torques due to the robot mass. Since most 6-DOF robots have three pitch joints, which are subject to gravitational torques, we propose a 3-DOF counterbalance mechanism based on the double parallelogram mechanism, in which reference planes are provided to each joint for proper counterbalancing. A 5-DOF counterbalance robot arm was built to demonstrate the performance of the proposed mechanism. Simulation and experimental results showed that the proposed mechanism had effectively decreased the torque required to support the robot mass, thus allowing the prospective use of low-cost motors and speed reducers for high-performance robot arms.

Original languageEnglish
Article number6774435
Pages (from-to)1756-1763
Number of pages8
JournalIEEE/ASME Transactions on Mechatronics
Issue number6
Publication statusPublished - 2014 Dec


  • Counterbalance mechanism
  • counterbalance robot arm
  • low-cost robot
  • manipulator design

ASJC Scopus subject areas

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


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