Robust and high-mobility walking control for uneven terrain without zero-moment-point feedback

2017 ◽  
Author(s):  
Kazuya Tamura ◽  
Atsuo Kawamura
Keyword(s):  
High Mobility ◽  
Zero Moment Point ◽  
Uneven Terrain ◽  
Walking Control ◽  
Zero Moment

scholarly journals A Robust Balance-Control Framework for the Terrain-Blind Bipedal Walking of a Humanoid Robot on Unknown and Uneven Terrain

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4194 ◽  
Author(s):  
Hyun-Min Joe ◽  
Jun-Ho Oh
Keyword(s):  
Humanoid Robot ◽  
Balance Control ◽  
Humanoid Robots ◽  
Bipedal Walking ◽  
Leg Length ◽  
Zero Moment Point ◽  
Uneven Terrain ◽  
Control Framework ◽  
Zero Moment ◽  
Capture Point

Research on a terrain-blind walking control that can walk stably on unknown and uneven terrain is an important research field for humanoid robots to achieve human-level walking abilities, and it is still a field that needs much improvement. This paper describes the design, implementation, and experimental results of a robust balance-control framework for the stable walking of a humanoid robot on unknown and uneven terrain. For robust balance-control against disturbances caused by uneven terrain, we propose a framework that combines a capture-point controller that modifies the control reference, and a balance controller that follows its control references in a cascading structure. The capture-point controller adjusts a zero-moment point reference to stabilize the perturbed capture-point from the disturbance, and the adjusted zero-moment point reference is utilized as a control reference for the balance controller, comprised of zero-moment point, leg length, and foot orientation controllers. By adjusting the zero-moment point reference according to the disturbance, our zero-moment point controller guarantees robust zero-moment point control performance in uneven terrain, unlike previous zero-moment point controllers. In addition, for fast posture stabilization in uneven terrain, we applied a proportional-derivative admittance controller to the leg length and foot orientation controllers to rapidly adapt these parts of the robot to uneven terrain without vibration. Furthermore, to activate position or force control depending on the gait phase of a robot, we applied gain scheduling to the leg length and foot orientation controllers, which simplifies their implementation. The effectiveness of the proposed control framework was verified by stable walking performance on various uneven terrains, such as slopes, stone fields, and lawns.

scholarly journals Dynamic Walking of a Legged Robot in Underwater Environments

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3588 ◽  
Author(s):  
Portilla ◽  
Saltarén ◽  
Espinosa ◽  
Barroso ◽  
Cely ◽  
...  
Keyword(s):  
Legged Robot ◽  
Dynamic Walking ◽  
Zero Moment Point ◽  
Hydraulic Actuators ◽  
External Perturbations ◽  
Underwater Environment ◽  
Zero Moment

In this research, the dynamic walking of a legged robot in underwater environments is proposed. For this goal, the underwater zero moment point (Uzmp) is proposed in order to generate the trajectory of the centre of the mass of the robot. Also, the underwater zero moment point auxiliary (Uzmp aux.) is employed to stabilize the balance of the robot before it undergoes any external perturbations. The concept demonstration of a legged robot with hydraulic actuators is developed. Moreover, the control that was used is described and the hydrodynamic variables of the robot are determined. The results demonstrate the validity of the concepts that are proposed in this article, and the dynamic walking of the legged robot in an underwater environment is successfully demonstrated.

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