Development and Balancing Control of Control Moment Gyroscope (CMG) Unicycle–Legged Robot

Shin, Seungchul; Choi, Minjun; Ahn, Seongmin; Hur, Seongyong; Kim, David; Choi, Dongil

doi:10.3390/machines13100937

Open AccessArticle

Development and Balancing Control of Control Moment Gyroscope (CMG) Unicycle–Legged Robot

by

Seungchul Shin

¹,

Minjun Choi

²,

Seongmin Ahn

³,

Seongyong Hur

⁴

,

David Kim

⁴ and

Dongil Choi

^4,*

¹

HL Klemove, Next M, Yongin 13453, Republic of Korea

²

Neuromeka, Econet Center, Seoul 04782, Republic of Korea

³

DH AUTOEYE, WOOMI NEWV, Hwaseong 18468, Republic of Korea

⁴

Department of Mechanical System Engineering, Myongji University, Yongin 17058, Republic of Korea

^*

Author to whom correspondence should be addressed.

Machines 2025, 13(10), 937; https://doi.org/10.3390/machines13100937

Submission received: 16 August 2025 / Revised: 30 September 2025 / Accepted: 7 October 2025 / Published: 10 October 2025

(This article belongs to the Special Issue Advances in Robot Kinematics and Dynamics: Innovations, Control Strategies, and Practical Applications)

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Abstract

A wheeled–legged robot has the advantage of stable and agile movement on flat ground and an excellent ability to overcome obstacles. However, when faced with a narrow footprint, there is a limit to its ability to move. We developed the control moment gyroscope (CMG) unicycle–legged robot to solve this problem. A scissored pair of CMGs was applied to control the roll balance, and the pitch balance was modeled as a double-inverted pendulum. We performed Linear Quadratic Regulator (LQR) control and model predictive control (MPC) in a system in which the control systems in the roll and pitch directions were separated. We also devised a method for controlling the rotation of the robot in the yaw direction using torque generated by the CMG, and the performance of these controllers was verified in the Gazebo simulator. In addition, forward driving control was performed to verify mobility, which is the main advantage of the wheeled–legged robot; it was confirmed that this control enabled the robot to pass through a narrow space of 0.15 m. Before implementing the verified controllers in the real world, we built a CMG test platform and confirmed that balancing control was maintained within

\pm 1^{\circ}

.

Keywords: wheeled–legged robot; motion control; balance stabilization

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MDPI and ACS Style

Shin, S.; Choi, M.; Ahn, S.; Hur, S.; Kim, D.; Choi, D. Development and Balancing Control of Control Moment Gyroscope (CMG) Unicycle–Legged Robot. Machines 2025, 13, 937. https://doi.org/10.3390/machines13100937

AMA Style

Shin S, Choi M, Ahn S, Hur S, Kim D, Choi D. Development and Balancing Control of Control Moment Gyroscope (CMG) Unicycle–Legged Robot. Machines. 2025; 13(10):937. https://doi.org/10.3390/machines13100937

Chicago/Turabian Style

Shin, Seungchul, Minjun Choi, Seongmin Ahn, Seongyong Hur, David Kim, and Dongil Choi. 2025. "Development and Balancing Control of Control Moment Gyroscope (CMG) Unicycle–Legged Robot" Machines 13, no. 10: 937. https://doi.org/10.3390/machines13100937

APA Style

Shin, S., Choi, M., Ahn, S., Hur, S., Kim, D., & Choi, D. (2025). Development and Balancing Control of Control Moment Gyroscope (CMG) Unicycle–Legged Robot. Machines, 13(10), 937. https://doi.org/10.3390/machines13100937

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

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Development and Balancing Control of Control Moment Gyroscope (CMG) Unicycle–Legged Robot

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