Mechanism Design of a Robotic Leg for Running Considering Radial Force Producibility and Tangential Mobility


A robotic leg of high-speed locomotion should be designed such that the mobility and the force producibility are maximized simultaneously. The mobility is crucial in a direction perpendicular to a line spanning from the head of upper limb to the tip of the lower limb, which is related to the rapid movement of the leg during swing. On the other hand, the force producibility is crucial in the same direction to the line, which is related to the thrust force of a leg in stance. In this paper, the tangential mobility and radial force producibility being defined mathematically, the mechanism design factors, i.e., an actuator configuration and a length ratio of upper limb and lower limb, are introduced, analysed, and determined for the leg to maximize both the tangential mobility and the radial force producibility. Applying the proposed design parameters, a robotic leg is fabricated, and the running motion is realized in experiment.

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Correspondence to Kyoungchul Kong.

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Recommended by Editor-in-Chief Keum-Shik Hong. This work was supported by Korea Evaluation Institute of Industrial Technology (KEIT) funded by the Ministry of Trade, Industry and Energy (MOTIE)(10080320).

Jungsoo Cho received his B.Eng. and M.S. degrees in Mechanical Engineering from Sogang University, Seoul, Korea, in 2012 and 2014, respectively. He is currently pursuing a doctorate degree at Sogang Graduate School. His main research interests include robust control and mechanism design of mechatronic systems.

Kyoungchul Kong received his B.Eng. (summa cum laude) degree in mechanical engineering and a B.S. degree in physics from Sogang University, Seoul, Korea, in 2004, an M.S. degree in mechanical engineering from Sogang University in 2006, and his Ph.D. degree in mechanical engineering from the University of California at Berkeley, Berkeley, CA, USA, in 2009. In 2011, he joined the Department of Mechanical Engineering, Sogang University, as an assistant and associate professor. Since 2019, he has been working at Korea Advanced Institute of Science and Technology (KAIST) as an associate professor. He has authored or co-authored about 200 technical articles in journals and conference proceedings in the area of mechatronics, including locomotive robotics and human-robot interactive systems. His current research interests include design, modeling, and control of mechatronic systems with an emphasis on locomotion and mobility of robotic systems. Dr. Kong received the Best Innovation Award from the President of South Korea in 2017, the Commendation by the Minister of Commerce, Industry and Energy in 2017, the Bronze Medal of Cybathlon in 2016, and the Young Researcher Award from the IFAC Mechatronics TC in 2016.

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Cho, J., Kong, K. Mechanism Design of a Robotic Leg for Running Considering Radial Force Producibility and Tangential Mobility. Int. J. Control Autom. Syst. 18, 1782–1791 (2020).

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  • Force producibility
  • legged robot
  • mechanism design
  • mobility
  • running