Search

The focus of this paper is the tolerance analysis of the deployable support truss frame structure. A parameter-driven three-dimensional tolerance analysis model is established, and the second-order tolerance analysis method is applied to obtain the contribution of the rod tolerance to the angle error of the antenna plates. To reduce manufacturing cost, the accuracy of the antenna plates is taken as the constraints, and the tolerance of each rod is regarded as a variable. The multi-island genetic algorithm is used to optimize the distribution of the tolerances of each member and obtain the minimum manufacturing cost which meets the functional requirements.

There are some problems in the design process of the separation system, such as the long time of modeling, simulation and analysis, and the difficulty of managing analysis results, which lead to low design efficiency and high error rate. In this paper, based on the secondary development of CAD/CAE software and the application of database, the automatic design method of spacecraft separation system is put forward. The simulation and analysis software of spacecraft separation is developed based on the integration of C++ and python, which effectively improves the efficiency and quality of product design.

In order to facilitate the design of the modular parabolic deployable mechanism, dimensional synthesis is carried out and a set of independent design variables are selected. Based on the parametric design, the structural dynamic analysis model of the mechanism is established, and the fundamental frequency and vibration mode are obtained. The fundamental frequency and mass are selected as indicators for the performance of the mechanism. The sensitivity analysis of independent design variables is carried out by the design of experiments method. The influence of independent design variables on the two indicators is obtained, which provides a basis for further design of the modular parabolic deployable mechanism.

To analyze the mechanical characteristics of cable-strut deployable articulated mast, its finite element analysis model was established. The first-order bending and torsional vibration frequencies were obtained by modal testing of 6 modules prototype. Based on the experimental results, the finite element model was updated considering uncertain conditions, and the model frequency error is reduced from 1.7% to 0.3%. Based on the updated simulation model, the effects of different module numbers and cable pre-tension on the fundamental frequency are studied. The results indicate that the number of modules is negatively correlated with the fundamental frequency, and the effect of cable pre-tension is positively.

The Heterogeneous Extensible Robot Open (HERO) platform is designed for autonomous robotic research. While bringing in the flexible computational capacities by CPU and FPGA, it addresses the challenges of heterogeneous computing by embracing OpenCL programming. We propose heterogeneous computing approaches for three fundamental robotic tasks: simultaneous localization and mapping (SLAM), motion planning and convolutional neural network (CNN) inference. With FPGA acceleration, the SLAM and motion planning tasks are performed 2–4 times faster on the HERO platform against fine-tuned software implementation. For CNN inference, it can process 20–30 images per second with the network of VGG-16 or ResNet-50. We expect the open platform and the developing experiences shared in this paper can facilitate future robotic research, especially for those compute intensive tasks of perception, movement and manipulation.

A dynamic analysis model of the novel lander is created, and all possible landing conditions at touchdown are considered. Through analyzing the landing process of free-fall landing mode, some shortcomings are found. To improve the landing stability of the novel lander, low-speed landing mode is proposed, namely, the main engine and attitude control engines are switched off soon after the lander is in contact with the landing surface. However, engine thrusts cannot disappear at the exact time when the lander contacts with the landing surface. So the influence of engine thrust on landing stability must be taken into consideration in the construction of the lander's model. Eleven forces, one of which is the thrust of the main engine and others simulate attitude control engines, are applied to the main body of the lander to create the analysis model for the low-speed landing mode. After analyzing and comparing the landing process of free-fall landing mode and low-speed landing mode, the conclusion that the low-speed landing mode has the better landing stability is obtained.

A novel approach to solving the robust topology optimization problem under loading uncertainty was developed. According to the superposition principle of linear structure, computational method for the excepted value and standard deviation of the compliance by Monte Carlo sampling is adopted. In order to avoid the computation of the sensitivity of the objective and improve computational efficiency, the proportional topology optimization method which shows comparable efficiency and accuracy with gradient-based method is used. The numerical examples demonstrate the effectiveness of the proposed approach.