State/Model-Free Variable-Gain Discrete Sliding Mode Control for an Ultraprecision Wafer Stage

2017 ◽  
Vol 64 (8) ◽  
pp. 6695-6705 ◽  
Author(s):  
Min Li ◽  
Kaiming Yang ◽  
Yu Zhu ◽  
Haihua Mu ◽  
Chuxiong Hu
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Free Variable ◽  
State Model ◽  
Variable Gain ◽  
Mode Control ◽  
Model Free ◽  
Discrete Sliding Mode Control

A Variable-Gain Discrete Sliding Mode Control Strategy With PID-Type Sliding Surface for an Ultra-Precision Wafer Stage

2016 ◽  
Author(s):  
Min Li ◽  
Yu Zhu ◽  
Kaiming Yang ◽  
Chuxiong Hu ◽  
Haihua Mu
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Frequency Noise ◽  
Main Concern ◽  
Sliding Surface ◽  
External Disturbances ◽  
Variable Gain ◽  
Mode Control ◽  
Ultra Precision ◽  
Discrete Sliding Mode Control

The ultra-precision wafer stage is an important mechatronic unit in a wafer scanner for manufacturing integrated circuits while its motion control is still the main concern. To overcome the performance-limiting trade-offs of fixed-gain discrete sliding mode control (DSMC), a novel variable-gain DSMC strategy with PID-type sliding surface is proposed for an ultra-precision wafer stage. Specially, PID-type sliding surface is employed to avoid the steady-state error induced by external disturbances. Via the exponential reaching law approach, DSMC with PID-type sliding surface is synthesized. Variable-gain control methodology is newly introduced into DSMC, and the control gain varies with the trajectory phase that the wafer stage is in and the tracking error magnitude. Performance assessment on a developed wafer stage validates that with nano-scale tracking accuracy the proposed strategy not only improves the low-frequency tracking ability without the amplification of high-frequency noise, but also possesses the excellent robustness to external disturbances.

scholarly journals Fractional Order Adaptive Fast Super-Twisting Sliding Mode Control for Steer-by-Wire Vehicles with Time-Delay Estimation

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2424
Author(s):  
Yong Yang ◽  
Yunbing Yan ◽  
Xiaowei Xu
Keyword(s):  
Time Delay ◽  
Sliding Mode Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Time Delay Estimation ◽  
Lyapunov Theory ◽  
Delay Estimation ◽  
Mode Control ◽  
Model Free ◽  
Steer By Wire

It is difficult to model and determine the parameters of the steer-by-wire (SBW) system accurately, and the perturbation is variable with complex and changeable tire–road conditions. In order to improve the control performance of the vehicle SBW system, an adaptive fast super-twisting sliding mode control (AFST-SMC) scheme with time-delay estimation (TDE) is proposed. The proposed scheme uses TDE to acquire the lumped dynamics in a simple way and establishes a practical model-free structure. Then, a fractional order (FO) sliding mode surface and a fast super-twisting sliding mode control structure were designed on the basic super-twisting sliding mode to ensure fast convergence and high control accuracy. Since the uncertain boundary information of the actual system is unknown, a novel adaptive algorithm is proposed to regulate the control gain based on the control errors. Theoretical analysis concerning system stability is given based on the Lyapunov theory. Finally, the effectiveness of the method is verified through comparative experiments. The results show that the proposed TDE-AFST-FOSMC control scheme has the advantages of model-free, fast response and high accuracy.

Discrete sliding mode control with forgetting dynamic sliding surface

Mechatronics ◽  
2004 ◽  
Vol 14 (7) ◽  
pp. 737-755 ◽  
Author(s):  
Wen-Chun Yu ◽  
Gou-Jen Wang ◽  
Chun-Chin Chang
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Sliding Surface ◽  
Mode Control ◽  
Discrete Sliding Mode Control
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