Development of an Inverse Control Theory for Backlash Coupled Systems and Its Application to Mechatronics Systems

• Main Authors: J.L. Ou, 歐俊良
• Other Authors: 鄭榮偉
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/52963122947965453761

碩士 === 國立中正大學 === 機械系 === 89 === Non-smooth nonlinearities such as friction, backlash, and hysteresis appear in most real physical systems. For such systems, existing control theory offers some analysis tools but severely lacks of control synthesis methodologies. This thesis is aimed at developing appropriate control synthesis approaches for systems with non-smooth nonlinear coupling. The backlash-coupled system was adopted as the research carrier throughout the development. For backlash-coupled systems, Cheng and Hsu recently proposed a multi-loop backlash compensation scheme based on the inverse control principle. The primary advantage of their scheme is that it provides a standard design process directly taking into account of the non-smooth nonlinearity of interest, in this case, the backlash. The proposed approach can be applied to motion drive systems, robot manipulators, optical disk drives, gun turrets, etc. The objective of this research is to conduct a further comprehensive investigation into this inverse control approach including an experimental validation. The success of this study was hinged upon the introduction of a new two degrees-of-freedom pole placement control design into existing multi-loop design. The new design includes an extra design degree-of-freedom allowing for the incorporation of an internal model control or a loop-shaping mechanism for robustness and performance improvement without affecting the Diophantine equation used in the conventional pole placement control. The theoretical issues investigated include asymptotic stability, tracking performance and input saturation. Both numerical simulations and laboratory experiments were employed to validate the effectiveness of the proposed control approach. In addition to the multi-loop control design, an inverse control with backstepping design named backstepping inverse control for backlash coupled systems was also developed. The advantage of the backstepping approach lies in the sound stability analysis coming with the backstepping design when addressing the interaction between inner and outer loops. In summary, the contributions of this study are: 1.A new two degrees-of-freedom pole placement control design. The new design includes an extra design degree-of-freedom allowing for the incorporation of an internal model control or a loop-shaping mechanism for robustness consideration without affecting the Diophantine equation used in the pole placement control. 2.An improved multi-loop inverse control for backlash-coupled systems. Theoretical issues investigated include asymptotic stability, tracking performance, and an anti-windup compensation for input magnitude constraint. Both simulation and experimental validation were successfully conducted. 3.A backstepping inverse control scheme for backlash-coupled system. The backstepping design was proposed to explicitly take into account the dynamic interaction between inner and outer loops. Simulation study was conducted to illustrate the effectiveness of the backstepping inverse control scheme.