Siri Marte Schlanbusch

• Schlanbusch, Siri Marte & Zhou, Jing (2026). Predictor-based attitude control for rigid body systems with input delays. Automatica. ISSN 0005-1098. 187. doi: 10.1016/j.automatica.2026.112893. Full text in Research Archive Show summary

  Time-delays are a prevalent challenge for systems controlled over networks. This paper addresses the attitude tracking control problem of rigid bodies subject to input delays, where the attitude is parameterized by unit quaternions. A predictor-feedback controller is developed to compensate the delay, and achieve tracking. Two different cases are considered, where in the first case a stability result is given based on Lyapunovs method. In the second case, a dual to Lyapunov’s stability theorem based on a density function is used for analyzing the system stability for convergence of almost all solutions to the desired equilibrium. The theoretical results are validated through experiments on a two-degrees-of-freedom (2-DOF) helicopter system, illustrating the effectiveness of the proposed approach.

• Schlanbusch, Siri Marte; Zhou, Jing & Schlanbusch, Rune (2025). Quantized Predictor-Based Tracking Control for Input Delay Systems: Application to a Helicopter System. IEEE Conference on Decision and Control. Proceedings. ISSN 0743-1546. doi: https:/ieeexplore.ieee.org/document/10886553. Full text in Research Archive Show summary

  In this paper, the tracking control problem is studied for systems with quantized signals and communication delays. A bounded type of quantizer is introduced to reduce the communication transmission burden, where both control inputs and states are quantized. A predictor-feedback controller is designed to compensate for delays in the inputs, while boundedness of the tracking errors are achieved and practical stability is ensured. An application to a helicopter system is presented to show the effectiveness of the proposed predictor-based controller in a closed-loop configuration, and to illustrate the main findings.

• Hua, Minh Tuan; Sveen, Emil Mühlbradt; Schlanbusch, Siri Marte & Sanfilippo, Filippo (2024). Robust-Adaptive Two-Loop Control for Robots with Mixed Rigid-Elastic Joints. In NN, . (Eds.), International Conference on Intelligent Robots and Systems (IROS). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9798350377705. p. 11332–11339. doi: 10.1109/IROS58592.2024.10802178. Full text in Research Archive Show summary

  In robotics, while rigid joints are common due to their accuracy and fast response ability, elastic joints are wellknown for their safety when interacting with the environment. To harmonise the advantages of these joint types, robots with mixed rigid-elastic joints can be considered. In this paper, a robust-adaptive two-loop control algorithm is proposed to control this type of hybrid robots when there are uncertainties in system parameters. In the outer loop, a robust control algorithm is proposed to deal with the uncertainties in the parameters of the joint dynamics, together with an adaptive controller for the rigid joints. In the inner loop, another robust control algorithm is proposed to handle the uncertainties in system parameters of the elastic joint’s motor contribution, and a similar adaptive control algorithm is presented to manipulate the elastic joints’ motors. The stability of the system is assured by Lyapunov’s stability theory. Finally, simulations are conducted to verify the proposed control algorithm.

• Schlanbusch, Siri Marte & Zhou, Jing (2024). Adaptive Super-Twisting Sliding Mode Control of Uncertain Underactuated Cranes. IEEE Xplore Digital Library. doi: 10.1109/ICIT58233.2024.10540715. Full text in Research Archive
• Schlanbusch, Siri Marte & Zhou, Jing (2024). Adaptive predictor-based control for a helicopter system with input delays: Design and experiments. Journal of Automation and Intelligence (JAI). 3(1), p. 50–56. doi: 10.1016/j.jai.2024.02.001. Full text in Research Archive
• Schlanbusch, Siri Marte & Zhou, Jing (2023). Adaptive Control of an Uncertain 2-DOF Helicopter System with Input Delays. Proceedings of the Annual Conference of the IEEE Industrial Electronics Society (IECON). ISSN 1553-572X. Full text in Research Archive Show summary

  In this paper, we consider a 2-degrees-of-freedom (DOF) helicopter system subject to input delays and uncertain system parameters. To address this challenge in control design, we develop an adaptive predictor-feedback control law. The control law is designed to compensate for a known delay while considering the system uncertainty. Stability of the closed-loop system is established, where tracking is achieved. We demonstrate the effectiveness of our proposed control approach through simulations of the helicopter system, where the input delays are compensated in the control-loop.

• Schlanbusch, Siri Marte & Zhou, Jing (2023). Adaptive quantized control of uncertain nonlinear rigid body systems. Systems & control letters (Print). ISSN 0167-6911. 175. doi: 10.1016/j.sysconle.2023.105513. Full text in Research Archive Show summary

  This paper investigates the attitude tracking control problem for uncertain nonlinear rigid body systems, where both inputs and states are quantized. It is common in networked control systems that sensor and control signals are quantized before they are transmitted via a communication network. An adaptive backstepping control algorithm is developed for a class of uncertain multiple-input multiple-output (MIMO) systems where a class of sector bounded quantizers is considered. It is shown that all the closed-loop signals are ensured uniformly bounded and tracking is achieved. Further, the tracking errors are shown to converge towards a compact set containing the origin and the set can be made small by the choice of the quantization parameters and the control parameters. For illustration of the proposed control scheme, experiments were conducted on a 2 degrees-of-freedom (DOF) helicopter system.

• Zhou, Jing & Schlanbusch, Siri Marte (2022). Adaptive Quantized Control of Offshore Underactuated Cranes with Uncertainty. IEEE International Conference on Control and Automation. ISSN 1948-3449. p. 297–302. doi: 10.1109/ICCA54724.2022.9831937. Full text in Research Archive Show summary

  The anti-swing control of offshore cranes presents much more challenges. Most existing controllers for offshore cranes are designed based on linearized dynamics and require the accurate values of the plant parameters. In this paper, an adaptive sliding mode control scheme is investigated for a nonlinear underactuated crane system with unmodeled dynamics. The proposed control method can ensure asymptotic stability and does not need linearization of the complicated nonlinear dynamic equations during controller design and stability analysis. To reduce the communication burden in a network, a uniform quantizer is introduced in the input communication channel. A quantized adaptive sliding mode control scheme is further developed for the underactuated cranes to compensate for the effects of input quantization and uncertain parameters. The proposed controller together with the quantizer ensures the asymptotic stability of the closed-loop system in the sense of signal boundedness and zero stabilization error. Numerical simulations are conducted to illustrate the effectiveness of proposed schemes.

• Schlanbusch, Siri Marte; Aamo, Ole Morten & Zhou, Jing (2022). Attitude Control of a 2-DOF Helicopter System with Input Quantization and Delay. Proceedings of the Annual Conference of the IEEE Industrial Electronics Society (IECON). ISSN 1553-572X. doi: 10.1109/IECON49645.2022.9968994. Full text in Research Archive Show summary

  In this paper the attitude tracking control problem of a 2 degrees-of-freedom helicopter system with network induced constraints is studied. A predictor feedback control law is developed to compensate a known delay in the communication, where the inputs are quantized before transmitted over the network. Stability of the closed-loop system is established, where tracking is achieved with bounded tracking errors due to the network issues. The developed predictor-based controller is experimentally tested on the helicopter system, where we demonstrate that tracking is achieved in presence of both input delay and quantization.

• Schlanbusch, Siri Marte; Zhou, Jing & Schlanbusch, Rune (2021). Adaptive Attitude Control of a Rigid Body with Input and Output Quantization. IEEE transactions on industrial electronics (1982. Print). ISSN 0278-0046. 69(8), p. 8296–8305. doi: 10.1109/TIE.2021.3105999. Full text in Research Archive Show summary

  In this paper, the adaptive attitude tracking the problem of a rigid body is investigated where the input and output are transmitted via a network. To reduce the communication burden in a network, a quantizer is introduced in both uplink and downlink communication channels. An adaptive backstepping-based control scheme is developed for a class of multiple-input and multiple-output (MIMO) rigid body systems. The proposed control algorithm can overcome the difficulty to proceed with the recursive design of virtual controls with quantized output vector and a new approach to stability analysis is developed by constructing a new compensation scheme for the effects of the vector output quantization and input quantization. It is shown that all closed-loop signals are ensured uniformly bounded and the tracking errors converge to a compact set containing the origin. Experiments on a 2 degrees-of-freedom helicopter system illustrate the effectiveness of the proposed control scheme.

• Schlanbusch, Siri Marte & Zhou, Jing (2021). Adaptive Backstepping Control of a 2-DOF Helicopter System in the Presence of Quantization. In Plapper, Peter (Eds.), 2021 IEEE The 9th International Conference on Control, Mechatronics and Automation. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781728137865. doi: 10.1109/ICCMA54375.2021.9646184. Full text in Research Archive Show summary

  This paper studies the attitude tracking control for an uncertain 2-degrees of freedom helicopter system where the inputs and the states are quantized. An adaptive backstepping based control scheme is proposed to handle the effect of quantization for tracking of reference angles for pitch and yaw. All closed-loop signals are ensured uniformly bounded and the tracking errors will converge to a compact set containing the origin. Experiments on the helicopter system illustrate the proposed control scheme.

• Schlanbusch, Siri Marte; Zhou, Jing & Schlanbusch, Rune (2021). Adaptive Backstepping Attitude Control of a Rigid Body with State Quantization, Proceedings of 60th IEEE Conference on Decision and Control. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781728113982. p. 372–377. doi: 10.1109/CDC45484.2021.9683579. Full text in Research Archive Show summary

  In this paper, the attitude tracking control problem of a rigid body is investigated where the states are quantized. An adaptive backstepping based control scheme is developed and a new approach to stability analysis is developed by constructing a new compensation scheme for the effects of the vector state quantization. It is shown that all closed-loop signals are ensured uniformly bounded and the tracking errors converge to a compact set containing the origin. Experiments on a 2 degrees-of-freedom helicopter system illustrate the proposed control scheme.

• Schlanbusch, Siri Marte & Zhou, Jing (2020). Adaptive Backstepping Control of a 2-DOF Helicopter System with Uniform Quantized Inputs. Proceedings of the Annual Conference of the IEEE Industrial Electronics Society (IECON). ISSN 1553-572X. doi: 10.1109/IECON43393.2020.9254497. Full text in Research Archive Show summary

  This paper proposes a new adaptive controller for a 2-Degree of Freedom (DOF) helicopter system in the presence of input quantization. The inputs are quantized by uniform quantizers. A nonlinear mathematical model is derived for the 2-DOF helicopter system based on Euler-Lagrange equations, where the system parameters and the control coefficients are uncertain. A new adaptive control algorithm is developed by using backstepping technique to track the pitch and yaw position references independently. Only quantized input signals are used in the system which reduces communication rate and cost. It is shown that not only the ultimate stability is guaranteed by the proposed controller, but also the designers can tune the design parameters in an explicit way to obtain the required closed loop behavior. Experiments are carried out on the Quanser helicopter system to validate the effectiveness, robustness and control capability of the proposed scheme.

• Schlanbusch, Siri Marte & Zhou, Jing (2019). Adaptive Backstepping Control of a 2-DOF Helicopter. In Herder, J. & HosseinNia, Hassan (Ed.), Proceedings, 2019 IEEE 7th International Conference on Control, Mechatronics and Automation. IEEE Press. ISSN 9781728137865. p. 210–215. doi: 10.1109/ICCMA46720.2019.8988761. Full text in Research Archive

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• Schlanbusch, Siri Marte & Zhou, Jing (2020). Adaptive Backstepping Control in the Presence of Quantization: Application to a 2-DOF Helicopter System. Full text in Research Archive
• Schlanbusch, Siri Marte & Zhou, Jing (2023). Adaptive Control of Systems with Quantization and Time Delays. Universitetet i Agder. ISSN 9788284271286. Full text in Research Archive Show summary

  This thesis addresses problems relating to tracking control of nonlinear systems in the presence of quantization and time delays. Motivated by the importance in areas such as networked control systems (NCSs) and digital systems, where the use of a communication network in NCS introduces several constraints to the control system, such as the occurrence of quantization and time delays. Quantization and time delays are of both practical and theoretical importance, and the study of systems where these issues arises is thus of great importance. If the system also has parameters that vary or are uncertain, this will make the control problem more complicated. Adaptive control is one tool to handle such system uncertainty. In this thesis, adaptive backstepping control schemes are proposed to handle uncertainties in the system, and to reduce the effects of quantization. Different control problems are considered where quantization is introduced in the control loop, either at the input, the state or both the input and the state. The quantization introduces difficulties in the controller design and stability analysis due to the limited information and nonlinear characteristics, such as discontinuous phenomena. In the thesis, it is analytically shown how the choice of quantization level affects the tracking performance, and how the stability of the closed-loop system equilibrium can be achieved by choosing proper design parameters. In addition, a predictor feedback control scheme is proposed to compensate for a time delay in the system, where the inputs are quantized at the same time. Experiments on a 2-degrees of freedom (DOF) helicopter system demonstrate the different developed control schemes.

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