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The purpose of this research is to achieve a novel magnetic nutation drive for an industry robotic wrist reducer.

A novel magnetic nutation drive is proposed, and the structure and principle of the designed magnetic nutation drive are described in this study. Three-dimensional finite element analysis is used to compute the magnetic and torque of the magnetic nutation drive. Furthermore, a prototype of this novel magnetic nutation drive device is developed with 3D printing technology and tested to verify the feasibility of the proposed structure and principle.

The simulation and experimental results indicated that the proposed magnetic nutation drive device could meet the desired specifications, and that this novel magnetic nutation drive device successfully realized the non-contact transmission ratio of 105:1 required for a robotic wrist reducer.

This novel magnetic nutation drive is low-cost and easy to make and use, and which provides the non-contact transmission ratio of 105:1 required for a robotic wrist reducer.

For the first time, this research applies the permanent magnet drive technology to nutation drive and puts forward a new non-contact nutation drive mode. The novel drive mode can solve some problems of the traditional mechanical contact nutation drive, such as vibration, friction loss, mechanical fatigue and necessity of lubrication. The proposed non-contact nutation drive device can achieve a high reduction ratio with compact structure and can be suitable for industry application.

The purpose of this paper is to obtain the single-tooth stiffness, single-tooth time-varying meshing stiffness and comprehensive meshing stiffness of the internal and external face gears and to analyze the influence of the modulus, pressure angle and tooth width of each face gear on the single-tooth stiffness of the gear in nutation face gear transmission.

From the point of view of material mechanics, the gear teeth of nutation face gear are simplified as spacial variable cross-section beams. The shear deformation of gear teeth, the bending deformation of tooth root and the additional elastic deformation caused by the base deformation are gotten by simplified trapezoidal section method, thus the stiffness of nutation face gear teeth can be obtained. The comparison with finite element method results verifies the rationality of simplified trapezoidal section method for calculating the tooth stiffness of nutation face gear.

The variation of stiffness of internal and external face gears along the meshing line and tooth height in nutation face gear transmission is studied, and the variation laws of single tooth stiffness, single-tooth-pair mesh stiffness and single tooth time-varying meshing stiffness of nutation face gear teeth are obtained.

Nutation face gear transmission is a new type of transmission. The stiffness of face gear teeth is analyzed, and the variation rules of single tooth stiffness, single-tooth-pair mesh stiffness and single tooth time-varying meshing stiffness of nutation face gear teeth are obtained, which not only enriches the research of nutation face gear transmission but also has important guiding significance for the application of nutation face gear in engineering practice.

The purpose of this paper is to calculate the meshing stiffness of nutation face gear considering the roughness, establish the calculation method of time-varying meshing stiffness of rough tooth surface and analyze the influence of roughness, load and other factors on the meshing stiffness of tooth surface.

The Weierstrass–Mandelbrot (W-M) function in the Majumdar–Bhushan model is used to characterize the rough contact line of the tooth surface, the normal height and radius of the micro convex body are calculated and the contact flexibility of the contact point of the tooth surface is obtained. The contact flexibility and the bending shear deformation flexibility obtained previously are substituted into the improved deformation compatibility equation for iterative calculation, and the time-varying meshing stiffness of the nutation face gear considering the roughness is obtained.

Compared with ABAQUS finite element simulation results, it is found that the meshing stiffness curve of rough tooth surface is more gentle than that of smooth tooth surface, the meshing stiffness value is smaller and the meshing stiffness change is smaller at the position where the number of gear teeth coincide changes.

In the process of calculating contact deformation, the fractal theory W-M function is used to characterize the contact line of the rough nutation face gear, and the deformation coordination condition considering roughness is improved. Therefore, the method of time-varying meshing stiffness considering roughness can obtain more accurate results, which provides theory and data for the subsequent dynamics analysis of the nutation face gear transmission.

According to the requirements of servicing and deorbiting the failure satellites, especially the tumbling ones on geosynchronous orbit, this paper aims to design a docking mechanism to capture these tumbling satellites in orbit, to analyze the dynamics of the docking system and to develop a new collision force-limited control method in various docking speeds.

The mechanism includes a cone-rod mechanism which captures the apogee engine with a full consideration of despinning and damping characteristics and a locking and releasing mechanism which rigidly connects the international standard interface ring (Marman rings, such as 937B, 1194 and 1194A mechanical interface). The docking mechanism was designed under-actuated, aimed to greatly reduce the difficulty of control and ensure the continuity, synchronization and force uniformity under the process of repeatedly capturing, despinning, locking and releasing the tumbling satellite. The dynamic model of docking mechanism was established, and the impact force was analyzed in the docking process. Furthermore, a collision detection and compliance control method is proposed by using the active force-limited Cartesian impedance control and passive damping mechanism design.

A variety of conditions were set for the docking kinematics and dynamics simulation. The simulation and low-speed docking experiment results showed that the force translation in the docking phase was stable, the mechanism design scheme was reasonable and feasible and the proposed force-limited Cartesian impedance control could detect the collision and keep the external force within the desired value.

The paper presents a universal docking mechanism and force-limited Cartesian impedance control approach to capture the tumbling non-cooperative satellite. The docking mechanism was designed under-actuated to greatly reduce the difficulty of control and ensure the continuity, synchronization and force uniformity. The dynamic model of docking mechanism was established. The impact force was controlled within desired value by using a combination of active force-limited control approach and passive damping mechanism.

The characteristics of spherical robots, such as under-drive, non-holonomic constraints and strong coupling, make it difficult to establish its motion control model accurately. To improve the anti-interference performance of spherical robots in practical engineering, this paper proposes a spherical robot motion controller based on auto-disturbance rejection control (ADRC) with parameter tuning.

This paper considers the influences of the spherical shell, internal frame and pendulum on the movement of the spherical robot during the rotation to establish the multi-body dynamics model of the XK-I spherical robot. Due to the serious coupling problem of the dynamic model, the motion control state equation is constructed using linearization and decoupling. The XK-I spherical robot PSO-ADRC motion controller with parameter tuning function is designed by combining the state equation with the particle swarm optimization (PSO) algorithm. Finally, experiments are performed to evaluate the feasibility of PSO-ADRC in an actual case compared to ADRC, PSO-PID and PID.

By analyzing the required time to reach the expected value, the control stability and the fluctuation range of the standard deviation after reaching the expected value, the superiority of PSO-ADRC to ADRC, PSO-PID and PID is demonstrated in terms of the speed and anti-interference ability.

The proposed method can be applied to the robot control field.

A parameter-tuning method for auto-disturbance-rejection motion control of the spherical robot is proposed. According to the experimental results, the anti-interference ability of the spherical robot moving on uneven ground is improved. Therefore, it provides a foundation for the autonomous environmental monitoring of the spherical robot equipped with sensors.

This study aims to design a controller which can improve the end-effector low-frequency chattering resulting from the measurement noise and the time delay in the on-orbit tasks. The rendezvous point will move along the rendezvous ring owing to the error of the camera, and the manipulators’ collision need be avoided. In addition, owing to the dynamics coupling, the manipulators’ motion will disturb the spacecraft, and the low tracking accuracy of the end-effector needs to be improved.

This paper proposes a minimum disturbance controller based on the synchronous and adaptive acceleration planning to improve the tracking error and the disturbance energy. The synchronous and adaptive acceleration planning method plans the optimal rendezvous point and designs synchronous approaching method and provides an estimation method of the rendezvous point acceleration. A minimum disturbance controller is designed based on the energy conservation to optimize the disturbance resulting from the manipulator’s motion.

The acceleration planning method avoids the collision of two end-effectors and reduces the error caused by the low-frequency chattering. The minimum disturbance controller minimizes the disturbance energy of the manipulators’ motion transferred to the spacecraft. Experiment results show that the proposed method improves the low-frequency chattering, and the average position tracking error reduces by 30%, and disturbance energy reduces by 30% at least. In addition, it has good performances in the synchronous motion and adaptive tracking.

Given the immeasurability of the target satellite acceleration in space, this paper proposes an estimation method of the acceleration. This paper proposes a synchronous and adaptive acceleration planning method. In addition, the rendezvous points are optimized to avoid the two end-effectors collisions. By the energy conservation, the minimum disturbance controller is designed to ensure a satisfying tracking error and reduce the disturbance energy resulting from the manipulators’ motion.

With the continuous development of aerospace technology, space exploration missions have been increasing year by year, and higher requirements have been placed on the upper level rocket. The purpose of this paper is to improve the ability to identify and detect potential targets for upper level rocket.

Aiming at the upper-level recognition of space satellites and core components, this paper proposes a deep learning-based spatial multi-target recognition method, which can simultaneously recognize space satellites and core components. First, the implementation framework of spatial multi-target recognition is given. Second, by comparing and analyzing convolutional neural networks, a convolutional neural network model based on YOLOv3 is designed. Finally, seven satellite scale models are constructed based on systems tool kit (STK) and Solidworks. Multi targets, such as nozzle, star sensor, solar,etc., are selected as the recognition objects.

By labeling, training and testing the image data set, the accuracy of the proposed method for spatial multi-target recognition is 90.17%, which is improved compared with the recognition accuracy and rate based on the YOLOv1 model, thereby effectively verifying the correctness of the proposed method.

This paper only recognizes space multi-targets under ideal simulation conditions, but has not fully considered the space multi-target recognition under the more complex space lighting environment, nutation, precession, roll and other motion laws. In the later period, training and detection can be performed by simulating more realistic space lighting environment images or multi-target images taken by upper-level rocket to further verify the feasibility of multi-target recognition algorithms in complex space environments.

The research in this paper validates that the deep learning-based algorithm to recognize multiple targets in the space environment is feasible in terms of accuracy and rate.

The paper helps to set up an image data set containing six satellite models in STK and one digital satellite model that simulates spatial illumination changes and spins in Solidworks, and use the characteristics of spatial targets (such as rectangles, circles and lines) to provide prior values to the network convolutional layer.

SIGNIFICANT strides have been made in the development of advanced electrically‐suspended inertial components and systems capable of utilizing them. At Honeywell, considerable contract support by both the United States Navy and the United States Air Force, in addition to Company‐sponsored effort, has resulted in Electrically‐Suspended Gyros that have achieved accuracies of one or two orders of magnitude better than those of the best conventional gyros.

THE earliest origins of the Trident may be said to lie as far back as 1944 when we made some preliminary studies of the ways in which the newly arrived turbojet engine could be exploited for civil use. Our first thoughts were that the high consumption of the early centrifugal engines would restrict their practical use to short and medium hauls, and we envisaged a three‐engined aircraft with tail booms and engines buried in the rear of a short fuselage somewhat on the lines of a scaled‐up Vampire, capable of carrying 20 passengers over stages up to 750 statute miles and operating from 3,500—4,000 ft. runways.

This paper aims to present a novel method for identification and classification of rotational motion for uncontrolled satellites. These processes are shown in context of close proximity orbital operations. In particular, it includes a manipulator arm mounted on chaser satellite and used to capture target satellites. In such situations, a precise extrapolation of the target’s docking port position is needed to determine the manipulator arm motion. The outcome of this analysis might be used in future debris removal or servicing space missions.

Nonlinear, and in some special cases, chaotic nature of satellite rotational motion was considered. Four parameters were defined: range of motion toward docking port, dominant frequencies, fractal dimension of the motion and its time dependencies.

The qualitative analysis was performed for presented cases of spacecraft rotational motion and for each case the respective parameters were calculated. The analysis shows that it is possible to detect the type of rotational motion.

A novel procedure allowing to estimate the type of satellite rotational motion based on fractal approach was proposed.