US 12,124,228 B1
Learning control system and method for nano-precision motion stage
Fazhi Song, Harbin (CN); Kaixin Liu, Harbin (CN); Shuaiqi Chen, Harbin (CN); Yang Liu, Harbin (CN); and Jiubin Tan, Harbin (CN)
Assigned to Harbin Institute of Technology, Harbin (CN)
Filed by Harbin Institute of Technology, Harbin (CN)
Filed on May 31, 2024, as Appl. No. 18/731,174.
Claims priority of application No. 202310751744.6 (CN), filed on Jun. 25, 2023.
Int. Cl. G05B 13/02 (2006.01); G05B 19/19 (2006.01)
CPC G05B 13/0265 (2013.01) [G05B 19/19 (2013.01); G05B 2219/34048 (2013.01); G05B 2219/41439 (2013.01); G05B 2219/41453 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A learning control system for a nano-precision motion stage, comprising a closed-loop feedback section Sfb and a feedforward section Sff;
wherein the closed-loop feedback section Sfb comprises a motion trajectory generator Cr, a feedback controller Cfb a motion stage P, and a first Fourier transformer Cfft1; the motion trajectory generator Cr generates a desired motion trajectory r(t); the desired motion trajectory r(t) minus a position measurement signal yj(t) results in a motion error signal ej(t); the motion error signal ej(t) added to a feedforward signal uff,j(t) results in a feedback input signal efb,j(t); the feedback input signal efb,j(t) is input into the feedback controller Cfb to generate a feedback control signal ufb,j(t); the feedback control signal ufb,j(t) added to a disturbance signal dj(t) results in a total control signal uall,j(t); the total control signal uall,j(t) is transmitted to the motion stage P to generate an actual position signal yp,j(t); the actual position signal yp,j(t) added to a measurement noise signal vj(t) results in a position measurement signal yj(t); and the position measurement signal yj(t) is transformed into a frequency domain position measurement signal γj(w) by the first Fourier transformer Cfft1;
the feedforward section Sff comprises a second Fourier transformer Cfft2, a learning controller CILC, an iteration backward shift operator Cz, and a Fourier inverse transformer Cifft; the second Fourier transformer Cfft2 is configured to transform the motion error signal ej(t) to a frequency domain error signal ζj(w); the frequency domain error signal ζj(w) and a j-th frequency domain feedforward signal μff,j(w) are jointly input to the learning controller CILC to obtain a (j+1)-th frequency domain feedforward signal μff,j+1(w); the (j+1)-th frequency domain feedforward signal μff,j+1(w) is input into the iteration backward shift operator Cz to generate the j-th frequency domain feedforward signal μff,j(w); and the j-th frequency domain feedforward signal μff,j(w) is transformed into the feedforward signal uff,j(t) by the Fourier inverse transformer Cfft1; and
j represents an iteration experiment count, j≥1, t represents time, and w represents frequency.