A flexible brush mechanism is designed and mounted at the end of a seven-degree-of-freedom robotic arm to despin a tumbling target. The dynamics model of the flexible brush is established using the absolute nodal coordinate method (ANCF), and its contact collision with the solar wing of the tumbling target is analysed. The optimal control is proposed for a seven-degree-of-freedom robotic arm during despinning of a tumbling target while ensuring the global robustness and stability. Simulations verify that the despinning strategy can successfully eliminate the rotation speed and is feasible and effective.

In this paper, the whale optimization algorithm is used to realize the mission planning of Multi-Agile Earth Observation Satellites for multiple target points. First of all, in the face of the observation problem of mul ti-satellite multitarget points, the fitness function, which satisfies the constraints faced by satellites when observing target points, is proposed in this paper. Secondly, in order to solve the task allocation problem of Multi-satellite to Multi-target points, a task allocation method based on the maximal time window is proposed in this paper. Next, the new whale optimization algorithms that have emerged in recent years is introduced in this paper. Considering that there has been no research on applying this algorithm to the mission planning problem so far, this paper proposes a method to map its iterative formula from the real number domain to the observation sequence domain based on the iterative characteristics of the whale optimization algorithm. This method enables the whale optimization algorithm to realize the iteration of the satellite observation sequence. Finally, the effectiveness of the whale optimization algorithm in solving the multi-satellite multi-target points planning problem is verified by simulation experiments.

In this study, a fusion splicing system that facilitates the splicing of a monolithic linear array fiber end cap is constructed. The fusion splicing thermal field of the end cap irradiated by a CO₂ laser is theoretically simulated using the finite element method. The experimental fusion splicing temperature agrees well with the simulation results. The splicing strength, misalignment, and high-power withstanding capacity of the fusion-spliced monolithic linear 3-fiber end cap are investigated. The use of the fabricated device in a dual-grating spectral beam combination (SBC) is also demonstrated with three-channel laser beams, achieving a combined beam with near-diffraction-limited beam quality M²=1.101. It shows that the development of the monolithic linear array fiber end cap is meaningful for achieving a compact high-brightness SBC system.

This paper presents a novel solution to the control problem of end-effector robust trajectory tracking for space robot. External disturbance and system uncertainties are addressed. For the considered robot operating in free-floating mode, a Chebyshev neural network is introduced to estimate system uncertainties and external disturbances. An adaptive controller is then proposed. The closed-loop system is guaranteed to be ultimately uniformly bounded. The key feature of this proposed approach is that, by choosing appropriate control gains, it can achieve any given small level ofL2gain disturbance attenuation from external disturbance to system output. The tracking performance is evaluated through a numerical example.

To address challenges associated with high-dimensional coordination and strict physical constraints in fixed-base space manipulator tool transfer under zero gravity, this paper proposes a preference-conditioned safe reinforcement learning algorithm, which is called $\alpha$PPO-LAG ($\alpha$-Preference Proximal Policy Optimization with Lagrangian). The algorithm introduces a preference factor $\alpha$ to regulate the trade-off between task performance and physical safety through constraint-aware policy optimization. Meanwhile, an adaptive Lagrangian regulation mechanism based on constraint estimation is developed to improve safety satisfaction during training. Experimental results demonstrate that with $\alpha =0.5$, the proposed method achieves an average reward of 990, outperforming PPO-LAG with 881 and CPO with 915. Furthermore, $\alpha$PPO-LAG obtains a safety score of 0.935 while reducing the contact-force violation rate to 1.0% and maintaining a low end-effector velocity violation rate of 10.0%. The empirical safety-performance analysis reveals effective operating points under different safety preferences, providing a practical solution for safe and compliant fixed-base tool transfer in zero-gravity environments.