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The purpose of this paper is to develop an easily implemented and practical stabilizing strategy for the hardware-in-the-loop (HIL) system. As the status of HIL system in the ground verification experiment for space equipment keeps rising, the stability problems introduced by high stiffness of industrial robot and discretization of the system need to be solved ungently. Thus, the study of the system stability is essential and significant.

To study the system stability, a mathematical model is built on the basis of control circle. And root-locus and 3D root-locus method are applied to the model to figure out the relationship between system stability and system parameters.

The mathematical model works well in describing the HIL system in the process of capturing free-floating targets, and the stabilizing strategy can be adopted to improve the system dynamic characteristic which meets the needs of the practical application.

A method named 3D root-locus is extended from traditional root-locus method. And the improved method graphically displays the stability of the system under the influence of multivariable. And the strategy that stabilize the system with elastic component has a strong feasible and promotional value.

The purpose of this paper is to solve the ground verification and test method for space robot system capturing the target satellite based on visual servoing with time-delay in 3-dimensional space prior to space robot being launched.

To implement the approaching and capturing task, a motion planning method for visual servoing the space manipulator to capture a moving target is presented. This is mainly used to solve the time-delay problem of the visual servoing control system and the motion uncertainty of the target satellite. To verify and test the feasibility and reliability of the method in three-dimensional (3D) operating space, a set of ground hardware-in-the-loop simulation verification systems is developed, which adopts the end-tip kinematics equivalence and dynamics simulation method.

The results of the ground hardware-in-the-loop simulation experiment validate the reliability of the eye-in-hand visual system in the 3D operating space and prove the validity of the visual servoing motion planning method with time-delay compensation. At the same time, owing to the dynamics simulator of the space robot added in the ground hardware-in-the-loop verification system, the base disturbance can be considered during the approaching and capturing procedure, which makes the ground verification system realistic and credible.

The ground verification experiment system includes the real controller of space manipulator, the eye-in-hand camera and the dynamics simulator, which can veritably simulate the capturing process based on the visual servoing in space and consider the effect of time delay and the free-floating base disturbance.

The purpose of this paper is to develop a set of ground experiment system to verify the basic functions of space effector and the capturing reliability of space end-effector for the free-floating target payload in the three-dimensional space. The development of ground experiment system for space end-effector is essential and significant, because it costs too much to launch a space robot or other spacecraft and carry out operation tasks in space. Owing to the negligible gravity in space, which is different from that in the ground environment, ground experiment system for space end-effector should have the capability of verifying the basic functions of space effector and the reliability of space end-effector in capturing the free-floating target payload in space.

The ground experiment system for space end-effector mainly adopts the hybrid simulation method, which includes the real hardware experiment and software simulation. To emulate the micro-gravity environment, the contact dynamics simulator is applied to emulating the motion state of the free-floating target payload, while the admittance control is used to realize the “soft” capturing of space end-effector to simulate the real situation in space.

With the gravity compensation, the influence of gravity is almost eliminated and the results meet the requirements of the experiment. In the ground experiment, the admittance control is effective and the actual motion state of space end-effector capturing the target in space can be simulated. The experiment results show that space end-effector can capture the free-floating target payload successfully and hopefully have the ability to capture a free-floating target in space.

The system can verify space end-effector capturing the free-floating target payload in three-dimensional space and imitate the motion of space end-effector capturing the free-floating target in space. The system can also be modified and improved for application in the verification of space robot capturing and docking the target, which is valuable for the ground verification of space applications.

The purpose of this paper is to study the path optimization method of the manipulator in the lunar soil excavation and sampling process. The current research is a practical need for the excavation and sampling of the lunar soil in the lunar exploration project.

This paper proposes the objective function and constraints for path optimization during the excavation process of the lunar soil, regarding excavation time and energy consumption as the two key fitness indexes by analyzing the whole excavation process of the lunar soil. Specifically, the optimization is divided into two consecutive phases, one for the excavation path and the other one for joint motions. In the first phase, the Bézier polynomial is adopted to get the optimal excavation angle and reduce energy consumption. In the second phase, a method based on convex optimization, variable conversion and dynamic process discretization, is used to reduce excavation time and energy consumption.

Controlled experiments on the fine sand and the simulant lunar soil were conducted to verify the feasibility and effectiveness of the two phases of the optimization method, respectively.

The optimization method of the excavation tasks in this paper is of great value in theoretical and practical engineering, and it can be applied in other robotic operational tasks as well.

The aim of this paper is to prove that the manipulator is able to contact the environment compliantly, and reduce the instantaneous collision impact.

Cartesian impedance control law is introduced to interrelate the external force with the Cartesian position.

When the estimated external force sensor feedback is the input of the on‐line trajectory regeneration, a novel online motion plan could be performed in a task‐consistent manner keeping the interaction force within the acceptable tolerance. The proposed approach also proves that the manipulator is able to contact the environment compliantly, and reduce the instantaneous collision impact. The virtual decomposition control, simplifying the Cartesian impedance control application of the manipulator and guaranteeing the asymptotical stability of the entire system, is implemented to actualize the approach. Furthermore, adaptive dynamics joint controller is extended to all the joints for complementing the biggish friction.

With the proposed adaptive Cartesian impedance control and the online path planner, the robot will be manipulation‐friendly in an unstructured environment.