Wind-tolerant optimal closed loop controller design for a domestic atmospheric research airship. Issue 6 (20th April 2022)

• Record Type: Journal Article
• Authors: Amani, Sasan; Pourtakdoust, Seid H.; Pazooki, Farshad
• Is Part Of: Mechanics based design of structures and machines. Volume 50:Issue 6(2022)
• Page Start: 2046
• Page End: 2066
• Publication Date: 2022-04-20
• Subjects: Airship -- buoyancy -- LQR -- LQT -- optimal control; Structural analysis (Engineering) -- Periodicals; Structural design -- Periodicals; 624.17
• DOI: 10.1080/15397734.2020.1768865
• Languages: English
• ISSNs: 1539-7734

Abstract

Abstract: Airships are inherently sensitive to random atmospheric disturbances that could potentially make their data gathering and observation missions a formidable task. In this context robust closed loop feedback controllers are important. The present study is therefore focused on optimal feedback controller design of an indigenous domestically designed airship (DA) for added robustness against atmospheric disturbances. While the general airship six degrees of freedom (6DoF) governing equations of motion are mathematically nonlinear, one often needs to resort to local linearization methods to benefit from proven linear closed loop controller (CLC) design approaches. In this sense an optimal linear quadratic regulator/tracker (LQR/LQT) seems to be a viable alternative for DA control purposes whose implementation relies on local linearization of the 6DoF nonlinear equations around the instantaneous airship trajectory. In order to demonstrate the capabilities of the proposed CLC design against external turbulences, a random wind profile over the DA hull is assumed and the airship behavior is analyzed in regulation as well as the tracking mode. The results show that the proposed CLC design complies with the all mission requirements and adequately reduces the impact of environmental random wind fluctuations. Given the small computational time required for control gain and command determination within the LQR/LQT algorithm against the DA mission flight time, the proposed CLC can be utilized online as a feedback control strategy while the airship is performing any physical atmospheric experiment.