TY - JOUR
T1 - Compensation of nonlinear dynamics for energy/phase control of hopping robot
AU - Abe, Yoshitaka
AU - Katsura, Seiichiro
N1 - Funding Information:
This research was partially supported by the Ministry of Internal Affairs and Communications, Strategic Information and Communications R&D Promotion Programme (SCOPE) , 201603011 , 2020.
Publisher Copyright:
© 2021 Elsevier Inc.
PY - 2021/5
Y1 - 2021/5
N2 - Hopping height control is one of the difficult problems in legged control. Many kinds of research employ a leg spring for the supplement of energy, and model the robot as a spring-mass model. Feedback linearization enables to cancel the nonlinear terms theoretically. However, it is difficult to identify the nonlinear terms including the parameters precisely in the real world. This paper nominalizes the robot dynamics as the desired spring-mass system applying a disturbance observer. In order to realize the desired characteristics of the spring and the mass, the disturbance including the nonlinear terms is rejected firstly by a disturbance observer. To make the mass in the workspace as constant, the nominal inertia of the disturbance observer in the joint space is varied. Next, by adding the desired virtual elastic force, the robot dynamics is nominalized as the desired spring-mass system. Based on the nominalized spring-mass dynamics, hopping-height control using energy/phase control is implemented. While energy control is often used for hopping height control, the energy/phase control enables the hopping-height control and the spring-mass oscillation simultaneously. Constant hopping-height and stepwise hopping height are realized experimentally through the proposed control method. The simulations in the case of the ideal dynamics are also conducted for comparison.
AB - Hopping height control is one of the difficult problems in legged control. Many kinds of research employ a leg spring for the supplement of energy, and model the robot as a spring-mass model. Feedback linearization enables to cancel the nonlinear terms theoretically. However, it is difficult to identify the nonlinear terms including the parameters precisely in the real world. This paper nominalizes the robot dynamics as the desired spring-mass system applying a disturbance observer. In order to realize the desired characteristics of the spring and the mass, the disturbance including the nonlinear terms is rejected firstly by a disturbance observer. To make the mass in the workspace as constant, the nominal inertia of the disturbance observer in the joint space is varied. Next, by adding the desired virtual elastic force, the robot dynamics is nominalized as the desired spring-mass system. Based on the nominalized spring-mass dynamics, hopping-height control using energy/phase control is implemented. While energy control is often used for hopping height control, the energy/phase control enables the hopping-height control and the spring-mass oscillation simultaneously. Constant hopping-height and stepwise hopping height are realized experimentally through the proposed control method. The simulations in the case of the ideal dynamics are also conducted for comparison.
KW - Energy control
KW - Energy/phase control
KW - Hopping robot
KW - Hopping-height control
UR - http://www.scopus.com/inward/record.url?scp=85100241499&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85100241499&partnerID=8YFLogxK
U2 - 10.1016/j.precisioneng.2021.01.004
DO - 10.1016/j.precisioneng.2021.01.004
M3 - Article
AN - SCOPUS:85100241499
SN - 0141-6359
VL - 69
SP - 36
EP - 47
JO - Precision Engineering
JF - Precision Engineering
ER -