TY - JOUR
T1 - Directional singularity-robust torque control for gyroscopic actuators
AU - Berry, Andrew
AU - Lemus Perez, D.S.
AU - Babuska, Robert
AU - Vallery, Heike
N1 - Accepted Author Manuscript
PY - 2016
Y1 - 2016
N2 - Gyroscopic actuation is appealing for wearable applications due to its ability to impart free moments on a body without exoskeletal structures on the joints.We recently proposed an unobtrusive balancing aid consisting of multiple parallelmounted control moment gyroscopes (CMGs) contained within a backpack-like orthopedic corset. Using conventional CMG control techniques, geometric singularities result in a number of performance issues, including either unintended oscillations or freezing of the gimbals at certain alignments, which are typically mitigated by the addition of redundant actuators or by allowing errors in the generated moment; however, because of the minimalistic design of the proposed device and focus on accurate moment tracking, a new methodology is required. In this paper, a control scheme is proposed for non-redundant CMG systems in which oscillations at saturated states are avoided and all remaining singularities are efficiently escaped by exploiting the system geometry; due to its use of classification-specific singularity proximity measures that account for the command moment orientation, it is named the directional singularity-robust (DSR) control law. The performance of this control law is assessed in both simulations and hardware testing. The proposed method is suitable for a wide range of CMG systems, including both balancing and aerospace applications.
AB - Gyroscopic actuation is appealing for wearable applications due to its ability to impart free moments on a body without exoskeletal structures on the joints.We recently proposed an unobtrusive balancing aid consisting of multiple parallelmounted control moment gyroscopes (CMGs) contained within a backpack-like orthopedic corset. Using conventional CMG control techniques, geometric singularities result in a number of performance issues, including either unintended oscillations or freezing of the gimbals at certain alignments, which are typically mitigated by the addition of redundant actuators or by allowing errors in the generated moment; however, because of the minimalistic design of the proposed device and focus on accurate moment tracking, a new methodology is required. In this paper, a control scheme is proposed for non-redundant CMG systems in which oscillations at saturated states are avoided and all remaining singularities are efficiently escaped by exploiting the system geometry; due to its use of classification-specific singularity proximity measures that account for the command moment orientation, it is named the directional singularity-robust (DSR) control law. The performance of this control law is assessed in both simulations and hardware testing. The proposed method is suitable for a wide range of CMG systems, including both balancing and aerospace applications.
KW - control moment gyroscope (CMG)
KW - fall prevention
KW - torque control
KW - wearable robotics
UR - http://www.scopus.com/inward/record.url?scp=84988419472&partnerID=8YFLogxK
UR - http://resolver.tudelft.nl/uuid:83cf033a-8dfb-446b-958c-6d2c7b35d85b
U2 - 10.1109/TMECH.2016.2603601
DO - 10.1109/TMECH.2016.2603601
M3 - Article
SN - 1083-4435
VL - 21
SP - 2755
EP - 2763
JO - IEEE - ASME Transactions on Mechatronics
JF - IEEE - ASME Transactions on Mechatronics
IS - 6
ER -