{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T02:52:16Z","timestamp":1760151136189,"version":"build-2065373602"},"reference-count":39,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,2,17]],"date-time":"2022-02-17T00:00:00Z","timestamp":1645056000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012226","name":"Fundamental Research Funds for the Central Universities of China","doi-asserted-by":"publisher","award":["YWF-21-BJ-J-541"],"award-info":[{"award-number":["YWF-21-BJ-J-541"]}],"id":[{"id":"10.13039\/501100012226","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper proposes a unified attitude controller based on the modified linear active disturbance rejection control (LADRC) for a dual-tiltrotor unmanned aerial vehicle (UAV) with cyclic pitch to achieve accurate attitude control despite its nonlinear and time-varying characteristics during flight mode transitions. The proposed control algorithm has higher robustness against model mismatch compared with the model-based control algorithms. The modified LADRC utilizes the state feedbacks from the onboard sensors like IMU and Pitot tube instead of the mathematical model of the plane. It has less dependency on the accurate dynamics model of the dual-tiltrotor UAV, which can hardly be built. In contrast to the original LADRC, an actuator model is integrated into the modified LADRC to compensate for the non-negligible slow rotor flapping dynamics and servo dynamics. This modification eliminates the oscillation of the original LADRC when applied on the plant with slow-response actuators, such as propeller and rotors of the helicopter. In this way, the stability and performance of the controller are improved. The controller replaces the gain-scheduling or the control logic switching by a unified controller structure, which simplifies the design approach of the controller for different flight modes. The effectiveness of the modified LADRC and the performance of the unified attitude controller are demonstrated in both simulation and flight tests using a dual-tiltrotor UAV. The attitude control error is less than \u00b14\u00b0 during the conversion flight. The control rising time in different flight modes is all about 0.5 s, despite the variations in the airspeed and tilt angle. The flight results show that the controller guarantees high control accuracy and uniform control quality in different flight modes.<\/jats:p>","DOI":"10.3390\/s22041559","type":"journal-article","created":{"date-parts":[[2022,2,17]],"date-time":"2022-02-17T20:26:41Z","timestamp":1645129601000},"page":"1559","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Unified Accurate Attitude Control for Dual-Tiltrotor UAV with Cyclic Pitch Using Actuator Dynamics Compensated LADRC"],"prefix":"10.3390","volume":"22","author":[{"given":"Zexin","family":"Wang","sequence":"first","affiliation":[{"name":"School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yingxun","family":"Wang","sequence":"additional","affiliation":[{"name":"Institute of Unmanned System, Beihang University, Beijing 100191, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhihao","family":"Cai","sequence":"additional","affiliation":[{"name":"School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jiang","family":"Zhao","sequence":"additional","affiliation":[{"name":"School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ningjun","family":"Liu","sequence":"additional","affiliation":[{"name":"Institute of Unmanned System, Beihang University, Beijing 100191, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yanqi","family":"Zhao","sequence":"additional","affiliation":[{"name":"School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2534","DOI":"10.1109\/TMECH.2020.2983255","article-title":"Transition Optimization for a VTOL Tail-Sitter UAV","volume":"25","author":"Li","year":"2020","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Panigrahi, S., Krishna, Y.S.S., and Thondiyath, A. (2021). Design, Analysis, and Testing of a Hybrid VTOL Tilt-Rotor UAV for Increased Endurance. Sensors, 21.","DOI":"10.3390\/s21185987"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1695","DOI":"10.1007\/s11071-017-3759-8","article-title":"Trajectory tracking of a class of under-actuated thrust-propelled vehicle with uncertainties and unknown disturbances","volume":"90","author":"Kabiri","year":"2017","journal-title":"Nonlinear Dyn."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/j.paerosci.2018.03.007","article-title":"A survey of hybrid Unmanned Aerial Vehicles","volume":"98","author":"Saeed","year":"2018","journal-title":"Prog. Aerosp. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1114","DOI":"10.1109\/TMECH.2018.2820222","article-title":"Design and Implementation of a Hybrid UAV with Model-Based Flight Capabilities","volume":"23","author":"Ke","year":"2018","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"356","DOI":"10.1016\/j.comcom.2019.10.016","article-title":"An evaluative review of the VTOL technologies for unmanned and manned aerial vehicles","volume":"149","author":"Zhou","year":"2019","journal-title":"Comput. Commun."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/j.cja.2016.11.001","article-title":"Control techniques of tilt rotor unmanned aerial vehicle systems: A review","volume":"30","author":"Liu","year":"2017","journal-title":"Chin. J. Aeronaut."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"843","DOI":"10.1016\/j.cja.2016.06.001","article-title":"Numerical simulation of aerodynamic interaction for a tilt rotor aircraft in helicopter mode","volume":"29","author":"Ye","year":"2016","journal-title":"Chin. J. Aeronaut."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Johnson, W., Yamauchi, G., Derby, M., and Wadcock, A. (2002, January 6\u20139). Wind Tunnel Measurements and Calculations of Aerodynamic Interactions Between Tiltrotor Aircraft. Proceedings of the 41st Aerospace Sciences Meeting and Exhibit, Reno, NV, USA.","DOI":"10.2514\/6.2003-47"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Avanzini, G., Torasso, A., and de Matteis, G. (2011, January 6\u20139). Assessment of Helicopter Model Fidelity through Inverse Simulation. Proceedings of the AIAA Atmospheric Flight Mechanics Conference, Montreal, QC, Canada.","DOI":"10.2514\/6.2011-6299"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Haycock, B., and Grant, P. (2011, January 6\u20139). A Real-time Helicopter Model with Flexible Main Rotor Blades. Proceedings of the AIAA Modeling and Simulation Technologies Conference, Montreal, QC, Canada.","DOI":"10.2514\/6.2011-6278"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"723","DOI":"10.1016\/j.mechatronics.2012.03.003","article-title":"Design and construction of a novel quad tilt-wing UAV","volume":"22","author":"Cetinsoy","year":"2012","journal-title":"Mechatronics"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2535","DOI":"10.1016\/j.jfranklin.2013.01.014","article-title":"Fault tolerant flight control system for the tilt-rotor UAV","volume":"350","author":"Park","year":"2013","journal-title":"J. Frankl. Inst."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"673","DOI":"10.2514\/1.32750","article-title":"Flight Testing of the T-Wing Tail-Sitter Unmanned Air Vehicle","volume":"45","author":"Stone","year":"2008","journal-title":"J. Aircr."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Horn, J. (2019). Non-Linear Dynamic Inversion Control Design for Rotorcraft. Aerospace, 6.","DOI":"10.3390\/aerospace6030038"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Papachristos, C., Alexis, K., Nikolakopoulos, G., and Tzes, A. (2011, January 27\u201330). Model predictive attitude control of an unmanned Tilt-Rotor aircraft. Proceedings of the 2011 IEEE International Symposium on Industrial Electronics, Gdansk, Poland.","DOI":"10.1109\/ISIE.2011.5984282"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Valasek, J., Ito, D., and Ward, D. (2001, January 5\u20138). Robust dynamic inversion controller design and analysis for the X-38. Proceedings of the AIAA Guidance, Navigation, and Control Conference and Exhibit, Monterey, CA, USA.","DOI":"10.2514\/6.2001-4380"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"402","DOI":"10.2514\/2.4411","article-title":"Adaptive Model Inversion Flight Control for Tilt-Rotor Aircraft","volume":"22","author":"Rysdyk","year":"1999","journal-title":"J. Guid. Control. Dyn."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"156","DOI":"10.1016\/j.ifacol.2015.08.076","article-title":"INDI Control with Direct Lift for a Tilt Rotor UAV","volume":"48","author":"Mattei","year":"2015","journal-title":"IFAC-PapersOnLine"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"943","DOI":"10.1177\/0954410019886963","article-title":"Practical control implementation of tri-tiltRotor flying wing unmanned aerial vehicles based upon active disturbance rejection control","volume":"234","author":"Wang","year":"2020","journal-title":"Proc. Inst. Mech. Eng. Part G J. Aerosp. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1065","DOI":"10.1016\/j.conengprac.2013.03.009","article-title":"An acceleration measurements-based approach for helicopter nonlinear flight control using Incremental Nonlinear Dynamic Inversion","volume":"21","author":"Simplicio","year":"2013","journal-title":"Control Eng. Pr."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s11432-018-9647-6","article-title":"On the characteristics of ADRC: A PID interpretation","volume":"63","author":"Jin","year":"2020","journal-title":"Sci. China Inf. Sci."},{"key":"ref_23","unstructured":"Gao, Z. (2003, January 9\u201313). Scaling and bandwidth-parameterization based controller tuning. Proceedings of the 2003 American Control Conference, New York, NY, USA."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"32349","DOI":"10.1109\/ACCESS.2018.2842198","article-title":"Generalized Extended State Observer Based High Precision Attitude Control of Quadrotor Vehicles Subject to Wind Disturbance","volume":"6","author":"Shi","year":"2018","journal-title":"IEEE Access"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1400","DOI":"10.1109\/TCST.2017.2710951","article-title":"Active Disturbance Rejection Attitude Control for a Dual Closed-Loop Quadrotor Under Gust Wind","volume":"26","author":"Yang","year":"2017","journal-title":"IEEE Trans. Control Syst. Technol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1007\/s10846-019-01013-1","article-title":"Evaluation of the Disturbance Rejection Performance of an Aerial Manipulator","volume":"97","author":"Aydemir","year":"2019","journal-title":"J. Intell. Robot. Syst."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Cai, Z., Wang, Z., Zhao, J., and Wang, Y. (2021). Equivalence of LADRC and INDI controllers for improvement of LADRC in practical applications. ISA Trans., in press.","DOI":"10.1016\/j.isatra.2021.07.039"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Stevens, B.L., and Lewis, F.L. (2003). Aircraft Control and Simulation, Wiley-Interscience. [2nd ed.].","DOI":"10.1108\/aeat.2004.12776eae.001"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Dreier, M.E. (2007). Aerodynamic and Dynamic Modeling of Rotors. Introduction to Helicopter and Tiltrotor Flight Simulation, AIAA.","DOI":"10.2514\/4.862083"},{"key":"ref_30","unstructured":"Bernard, M. (2003). Identification of the Model. Identification Modeling and Characteristics of Miniature Rotorcraft, Springer."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Remple, R.K., and Tischler, M.B. (2006). Aircraft and Rotorcraft System Identification, Amer Inst of Aeronautics.","DOI":"10.2514\/4.861352"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s11432-019-2712-7","article-title":"A parameter formula connecting PID and ADRC","volume":"63","author":"Zhong","year":"2020","journal-title":"Sci. China Inf. Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"16606","DOI":"10.1109\/ACCESS.2020.2967806","article-title":"Linear Active Disturbance Rejection Control for Processes with Time Delays: IMC Interpretation","volume":"8","author":"Fu","year":"2020","journal-title":"IEEE Access"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1077","DOI":"10.1109\/TIE.2020.2970617","article-title":"Linear Active Disturbance Rejection Control for Servo Motor Systems with Input Delay via Internal Model Control Rules","volume":"68","author":"Li","year":"2020","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"75","DOI":"10.1049\/iet-cta:20050138","article-title":"Active disturbance rejection control for uncertain multivariable systems with time-delay","volume":"1","author":"Xia","year":"2007","journal-title":"IET Control Theory Appl."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"882","DOI":"10.1016\/j.isatra.2013.09.013","article-title":"Modified active disturbance rejection control for time-delay systems","volume":"53","author":"Zhao","year":"2014","journal-title":"ISA Trans."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Durham, W., Bordignon, K.A., and Beck, R. (2016). Solutions. Aircraft Control Allocation, Wiley.","DOI":"10.1002\/9781118827789"},{"key":"ref_38","first-page":"1756829319861370","article-title":"Attitude control of tiltwing aircraft using a wing-fixed coordinate system and incremental nonlinear dynamic inversion","volume":"11","author":"Binz","year":"2019","journal-title":"Int. J. Micro Air Veh."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1270","DOI":"10.1016\/j.mechmachtheory.2008.07.004","article-title":"A new trifilar pendulum approach to identify all inertia parameters of a rigid body or assembly","volume":"44","author":"Dan","year":"2009","journal-title":"Mech. Mach. Theory"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/4\/1559\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:21:31Z","timestamp":1760134891000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/4\/1559"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,2,17]]},"references-count":39,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2022,2]]}},"alternative-id":["s22041559"],"URL":"https:\/\/doi.org\/10.3390\/s22041559","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2022,2,17]]}}}