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Journal of Vibration Testing and System Dynamics

C. Steve Suh (editor), Pawel Olejnik (editor),

Xianguo Tuo (editor)

Pawel Olejnik (editor)

Lodz University of Technology, Poland


C. Steve Suh (editor)

Texas A&M University, USA


Xiangguo Tuo (editor)

Sichuan University of Science and Engineering, China


Modeling and Control of the Locomotion of a Monopod Robot Mounted to a Vertical Slider

Journal of Vibration Testing and System Dynamics 6(4) (2022) 413--430 | DOI:10.5890/JVTSD.2022.12.005

Siyuan Xing$^1$, Bradley Y.N. Kwan$^1$, Pengji Duan$^2$

$^1$ Department of Mechanical Engineering, California Polytechnic State University, San Luis Obispo, CA 93047, USA

$^2$ TuSimple, 9538 E Old Vail Rd, Tucson, AZ 85747, USA

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This paper studies the locomotion of a monopod robot mounted to a vertical slider. The robot is driven by two electric motors attached to its hip. Although the system is often used to develop and test low-level controllers of legged robots, its dynamics was only studied from the lumped model with massless legs. The actual system is more complex and interesting because it is over-actuated and single-degree-of-freedom during the stance phase but under-actuated and three-degree-of-freedom during the flight phase. In this paper, the equations of motion of the legged robot during stance and flight phases are established through the Euler-Lagrange method. The switching law governing phase transitions is derived based on the assumption of conversation of angular momentum. A phase-switching controller is proposed to stabilize dynamic gaits of the robot. Numerical simulations of the robot's locomotion with/without control are carried out through a Stateflow model. Results are validated through numerical simulations powered by Simscape Multibody. The effect of mass distribution of the hip and legs on jump height is discussed for optimized deign.


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