3 research outputs found
Interactive Physically-Based Simulation of Roadheader Robot
Roadheader is an engineering robot widely used in underground engineering and
mining industry. Interactive dynamics simulation of roadheader is a fundamental
problem in unmanned excavation and virtual reality training. However, current
research is only based on traditional animation techniques or commercial game
engines. There are few studies that apply real-time physical simulation of
computer graphics to the field of roadheader robot. This paper aims to present
an interactive physically-based simulation system of roadheader robot. To this
end, an improved multibody simulation method based on generalized coordinates
is proposed. First, our simulation method describes robot dynamics based on
generalized coordinates. Compared to state-of-the-art methods, our method is
more stable and accurate. Numerical simulation results showed that our method
has significantly less error than the game engine in the same number of
iterations. Second, we adopt the symplectic Euler integrator instead of the
conventional fourth-order Runge-Kutta (RK4) method for dynamics iteration.
Compared with other integrators, our method is more stable in energy drift
during long-term simulation. The test results showed that our system achieved
real-time interaction performance of 60 frames per second (fps). Furthermore,
we propose a model format for geometric and robotics modeling of roadheaders to
implement the system. Our interactive simulation system of roadheader meets the
requirements of interactivity, accuracy and stability
A Visual Interpretation-Based Self-Improved Classification System Using Virtual Adversarial Training
The successful application of large pre-trained models such as BERT in
natural language processing has attracted more attention from researchers.
Since the BERT typically acts as an end-to-end black box, classification
systems based on it usually have difficulty in interpretation and low
robustness. This paper proposes a visual interpretation-based self-improving
classification model with a combination of virtual adversarial training (VAT)
and BERT models to address the above problems. Specifically, a fine-tuned BERT
model is used as a classifier to classify the sentiment of the text. Then, the
predicted sentiment classification labels are used as part of the input of
another BERT for spam classification via a semi-supervised training manner
using VAT. Additionally, visualization techniques, including visualizing the
importance of words and normalizing the attention head matrix, are employed to
analyze the relevance of each component to classification accuracy. Moreover,
brand-new features will be found in the visual analysis, and classification
performance will be improved. Experimental results on Twitter's tweet dataset
demonstrate the effectiveness of the proposed model on the classification task.
Furthermore, the ablation study results illustrate the effect of different
components of the proposed model on the classification results
Design and Test of the Clearing and Covering of a Minimum-Tillage Planter for Corn Stubble
Conservation tillage technology can reduce wind erosion and soil erosion, improve soil fertility, avoid straw burning and relieve ecological pressure. It is an important measure to achieve sustainable agricultural development. In northeast China, there is a large amount of straw covering the ground after the corn machine harvest, which can easily lead to the blockage of the soil-touching parts during no-tillage seeding, affecting sowing quality and crop yield. In order to solve the above problems, the clearing and covering of a minimum-tillage planter for corn stubble was developed. The machine can complete multiple processes, such as seedbed preparation, seeding, fertilization, covering and suppression, straw covering, etc., in a single entity. This paper focuses on the design of the straw cleaning device and uses discrete element method software (EDEM 2018, Altair Engineering, Troy, MI, USA) to establish the straw cleaning device–straw–soil discrete element simulation model. The quadratic-regression orthogonal center-of-rotation combination test method is used to optimize the parameter combination of the machine, using the operating speed, the speed of the knife roller and the penetration depth of the knife as the test factors and using the rate of cleaning straw and the equivalent power consumption as the evaluation index. The results show that each factor has a significant influence on the performance evaluation indices, and the order of influence of each factor on the rate of cleaning straw is operation speed > penetration depth of knife > speed of knife roller, and the order of influence of each factor on the equivalent power consumption is penetration depth of knife > speed of knife roller > operation speed. The optimal combination of parameters is a 5.5–6.2 km/h operation speed, a 500 rpm speed of the knife roller, a 40 mm penetration depth of the knife, a straw-cleaning rate of more than 90% and an equivalent power consumption of less than 8 kW. This study provides technical and equipment support for the promotion of conservation tillage technology in Northeast China