Study on the state-dependent path-tracking for smart pneumatic shock-absorber

Abstract

The paper presents an analysis of the state-dependent path-tracking method devoted to mitigation of dynamic response of systems and structures under impact excitations. The objective of the study is an evaluation of the adaptive performance and robustness of the novel control method. Robust and adaptive control methods are intensively developed by researchers and control engineers. Progress in the field influences various areas including mechanical engineering, within which these methods are applied for control of industrial processes as well as mitigation of structure dynamic response. Commonly solved problems relate especially to mitigation of vibrations, e.g. for protection of seismically excited structures. Another closely related area is the field of impact absorption, which is still challenging because of short time periods of energy absorption and number of process uncertainties. Nevertheless, due to higher and higher performance of smart sensors and actuators, as well as increasing efficiency of data processing systems, novel high-performance solutions also for impact mitigation problems can be proposed. This fact is reflected in the paper and important contribution to the field of Adaptive Impact Absorption is demonstrated. The importance of presented study results from the fact that applied smart absorber controlled with the use of kinematics-based approach ensures efficient mitigation of the impact excitation and automatic adaptation to various loading conditions. In contrast to shock-absorbers developed so far, the system implemented in laboratory provides adaptation to unknown impact conditions and compensates the influence of unpredictable perturbations. Within the paper an experimental validation of the novel control method is discussed and the system robustness to contact conditions, as well as to different values of operational medium parameters, is demonstrated. Possible extension of the method is analyzed and directions of further research are indicated.

Identification-based predictive control of semi-active shock-absorbers for adaptive dynamic excitation mitigation

“…The disadvantage of the classical approach is the fact that system relies on the quality of initial excitation identification and robustness to possible disturbances in the impact absorption process is not provided. This problem was addressed by the authors in previous papers, where consequences of imprecise initial identification of the excitation has been revealed [35], the method providing self-adaptive performance of the fluid-based absorbers has been introduced [36] and experimentally validated using drop tests [37]. This paper proposes new control methods, which are based on the identification of excitation parameters, but in contrast to the original AIA approach the identification is not treated as a separate process performed before single calculation of the control strategy at the beginning of impact absorption process.…”

Adaptive Impact Mitigation Based on Predictive Control with Equivalent Mass Identification

“…Such an approach leads to the state-dependent path-tracking problem, which can be repeatedly solved at each control step in order to determine the actually optimal valve control. The simplified solution to the problem is hybrid prediction control (HPC) [42] based on combination of digital (on/off) and analogue (proportional) control, which has been tested numerically and validated experimentally using drop tests [43]. A more exact solution determined for the case of unknown excitation and disturbance force leads to identification-based predictive control (IPC) [44], which includes the identification of external forces, repeated at each control step, and sequential solution of the optimal control problem.…”

Semi-active vibration control based on switchable transfer of bending moments: study and experimental validation of control performance

“…A compromise between passive and active solutions is offered by the semi-active approach, which combines their advantages [3]. It operates by flexibly adapting local stiffness and damping characteristics in order to achieve the desired level of mitigation of vibrations without introducing large external control forces [4]. The actuators are characterized by low energy consumption, and acceptable weight and volume.…”