Since space intelligent robots are not restricted by physiological conditions, it is an attractive choice for the development of automation technology to use them for space exploration and utilization. It is currently the key development direction of the major space powers over the world. This paper first investigates the robotic manipulators and humanoid robot systems for space station applications and reviews theories and methods for robots to achieve large-range stable motion and intelligent dexterous manipulation. Then, the intelligent robot systems for on-orbit satellite maintenance are reviewed, and the related technologies of multirobot collaboration are analyzed. Finally, we investigate the intelligent robot systems for on-orbit assembly of large-scale spatial structures and summarize the technologies of modular assembly and on-orbit manufacture. Overall, this paper reviews the technological progress and development trends of space robots, which provides a good reference for further technical research in this field.

Using robots to assist or even replace rescuers for searching and rescuing has always been a research hotspot. Robots that can carry out dexterous operations at the scene are of great significance to reduce the life threat of rescue workers. Aiming at the characteristics of narrow space and frequent physical interaction in rescue scene, a dual-arm mobile robot BIT-DMR composed of humanoid upper body and tracked mobile platform is developed in this letter. The main work is as follows: a) A high-performance lightweight and heavy payload human-machine cooperative manipulator is developed, which has a slender shape and a large flexible workspace, improving the operation ability of the robot in complex rescue environment. b) A highly integrated tracked mobile platform is developed, which can change a variety of forms leading to a high trafficability in complex terrain. The flexibility of BIT-DMR to carry out rescue operation is verified by a series of experiments like payload testing, mobile platform performance, obstacle removing, door opening and casualty rescuing. This letter provides technical reserves for robots to assist or replace human beings to carry out rescue operations at the scene.

Safe and efficient coordinated motion planning is crucial for the dual-arm robot's manipulation in the constrained environment. This article studies a fast optimization-based coordinated motion planning method for dual-arm robots based on a parallel differential dynamic programming (DDP) solver. First, the proposed method models the unstructured environment using swept sphere volumes and turns the safety and task constraints, including collision avoidance, path constraints, and closed kinematics constraints, into mathematical equalities and inequalities in an optimization problem. Second, to efficiently solve this high-dimensional and multiconstraint optimization problem, a parallel constrained differential dynamic programming (PC-DDP) solver is developed based on a new multiple shooting strategy. It utilizes the augmented Lagrangian method to handle various constraints and achieves high solving efficiency using the parallelization strategy with an approximation and the serial correction of the value function. Simulations and experiments of opening doors and transferring the box are conducted on the robot with dual 7-DOF manipulators. The results show that the proposed method works well in the motion planning of coordinated manipulations in constrained environments and that the PC-DDP is much faster than other DDP variants and large-scale optimization solvers.

Controlling a robot astronaut to move in the same way as a human astronaut to realize a wide range of motion in a space station is an important requirement for the robot astronauts that are meant to assist or replace human astronauts. However, a robot astronaut is a nonlinear and strongly coupled multibody dynamic system with multiple degrees of freedom, whose dynamic characteristics are complex. Therefore, implementing a robot astronaut with wide-ranging motion control in a space station is a tremendous challenge for robotic technology. This article presents a wide-ranging stable motion control method for robot astronauts in space stations based on human dynamics. Focusing on the astronauts’ parking motion in a space station, a viscoelastic dynamic humanoid model of parking under microgravity environment was established using a mass–spring–damper system. The model was used as the expected model for stable parking control of a robot astronaut, and the complex dynamic characteristics were mapped into the robot astronaut system to control the stable parking of the robot astronaut in a manner similar to a human astronaut. This provides a critical basis for implementing robots that are capable of steady wide-ranging motion in space stations. The method was verified on a dynamic system of a robot astronaut that was constructed for this research. The experimental results showed that the method is feasible and effective and that it is a highly competitive solution for robot astronauts with human-like moving capabilities in space stations.

On-orbit assembly has become a crucial aspect of space operations, where the manipulator frequently and directly interacts with objects in a complex assembly process. The traditional manipulator control has limitations in adapting to diverse assembly tasks and is vulnerable to vibration, leading to assembly failure. To address this issue, we propose a human-like variable admittance control method based on the variable damping characteristics of the human arm. By collecting the velocity and contact force of human arm operations in assembly, we analyze the damping change of human arm and establish the active compliance model based on S-type damping variation rule in assembly. Furthermore, 3 passive contact models are proposed between the end of the human arm and the environment: one-sided bevel contact, both sides bevel contact, and pin–hole contact. On the basis of these active and passive models, a typical space assembly task for a robot is designed, and a human-like variable admittance controller is established and simulated. Finally, we build a ground verification platform and complete different assembly tasks, thereby successfully verifying the safety, robustness, and adaptability of the human-like variable admittance control method.