Context:

Orbit removal and servicing tasks are expected to play a key role in future space missions. These challenging operations often rely on robotic manipulation to achieve mission objectives. Although robotic manipulators are already used in current space missions, they are typically teleoperated, due to the complexity of controlling them from a free-floating platform.

The goal of this PhD thesis is to design autonomous control strategies for performing rendezvous and grasping of a non-cooperative object using a Space Manipulator System (SMS).

Research Objectives:

In on-orbit capture scenarios, the integration of visual sensors can significantly enhance the autonomy of an SMS operating in a complex and dynamic environment [1]. Vision-based control strategies enable the approach, capture, and manipulation of a target by controlling the relative motion between the robot and the object based on real-time visual feedback. However, several challenges must be overcome to ensure reliable on-orbit servicing, including robust target identification, precise trajectory planning, and accurate control during the approach and contact phases [2, 3, 4]. These scenarios highlight the need for advanced control algorithms capable of handling complex dynamics and constraints. Model Predictive Control (MPC) represents a promising approach in this context: it formulates an optimization problem using a system’s dynamic model to compute an optimal control sequence that satisfies multiple constraints (e.g., on states, inputs, or outputs). Moreover, to address model uncertainties—such as flexible elements or the capture of an unknown target—adaptive control strategies offer an effective framework for enhancing the robustness of model-based control laws previously proposed [5].

In terms of modeling and simulation, our research group at ONERA has developed a high-fidelity simulation platform for the design, validation, and benchmarking of different control strategies [5, 6]. In the course of an ONERA project in which On-Orbit Assembly of a large structure with crawling robot is studied,, these tools are extended to include contact and grasping dynamics based on Lagrangian approaches. 

Therefore, the main objectives of this PhD thesis are as follows:

    • Investigate predictive control strategies to ensure a smooth and safe approach of the servicer towards the target.

    • Develop adaptive control strategies for the detumbling phase, i.e., stabilizing the captured object without disturbing the base satellite.

    • Leverage ONERA’s simulation tools to extend their capabilities, integrate new features, and validate the proposed control strategies.

    • Propose and benchmark novel control solutions against state-of-the-art approaches in realistic mission scenarios.

Project Description:

To achieve these objectives, the research will follow the steps outlined below:

    • Conduct an extensive literature review on vision-based control approaches, focusing on adaptive and predictive control strategies for on-orbit operations with SMS [1].

    • Extend ONERA’s simulation tools and platform [6] to validate the proposed control strategies in representative capture scenarios.

    • Design and compare control algorithms against state-of-the-art methods.

    • Investigate Model Reference Adaptive Control (MRAC) strategies to reduce reliance on accurate system models in model-based approaches.

    • Develop and implement MPC-based control laws to safely approach and capture uncooperative targets under actuator and workspace constraints.

    • Integrate and test the proposed control laws within the simulation platform to assess performance, robustness, and feasibility.

References:

[1] L. M. Amaya-Mejıa, M. Ghita, J. Dentler, M. Olivares-Mendez Miguel et Carol, Visual Servoing for Robotic On-Orbit Servicing: A Survey, International Conference on Space Robotics (iSpaRo) (2024).

[2] Y. Shi, B. Liang, X. Wang, W. Xu et H. Liu, Modeling and simulation of space robot visual servoing for autonomous target capturing, in 2012 IEEE International Conference on Mechatronics and Automation, pp. 2275–2280. IEEE (2012).

[3] . P. Alepuz, M. R. Emami et J. Pomares, Direct image-based visual servoing of free-floating space manipulators, Aerospace Science and Technology, 55, pp. 1–9 (2016).

[4] . Zhao, M. R. Emami et S. Zhang, Image-based control for rendezvous and synchronization with a tumbling space debris, Acta Astronautica, 179, pp. 56–68 (2021).

[5] S. Kraïem, Development of steering law for On Orbit Servicing operation, Thèse de doctorat, Institut Supérieur de l’Aéronautique et de l’Espace (ISAE) (2022)

[6] S. Kraïem, M. Rognant, S. Waitman, Simulation platform to design and validate control laws for a space manipulator system performing on-orbit servicing, International Conference on Space Robotics (iSpaRo) (2024).

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For more Information about the topics and the co-financial partner (found by the lab!); contact Directeur de thèse - sofiane.kraiem@onera.fr

Then, prepare a resume, a recent transcript and a reference letter from your M2 supervisor/ engineering school director and you will be ready to apply online before March 13th, 2026 Midnight Paris time!