With the development of technology, parallel mobile robots have been paid more attention in various industries due to the strong load capacity, high running stability and rapid response speed. However, step-length opt...
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With the development of technology, parallel mobile robots have been paid more attention in various industries due to the strong load capacity, high running stability and rapid response speed. However, step-length optimization is an important but challenging task for this kind of mobile robot. Step length has dramatic effect on the stability of robot and the performance of electric cylinder. Balancing the speed characteristics and stability margin, we propose a genetic algorithm to solve this problem and design a novel fitness function that can measure the motion characteristics of parallel mobile robot. Effectiveness of our method is verified by experiments.
The brain-computer interface (BCI) plays an important role in assisting the disabled in life support and entertainment. In this study, a wireless retrieval robot system for steady-state visual evoked potential (SSVEP)...
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ISBN:
(数字)9781728176871
ISBN:
(纸本)9781728176888
The brain-computer interface (BCI) plays an important role in assisting the disabled in life support and entertainment. In this study, a wireless retrieval robot system for steady-state visual evoked potential (SSVEP) based BCI system was proposed. In order to improve the recognition accuracy and system stability of BCI system for subjects' instructions, in this study, offline and online experiments are used to study and solve the performance parameters, obstacle avoidance and retrieval performance of BCI respectively. In the offline experiment, 5 types of SSVEP data of 4 subjects were used. Based on CCA algorithm, the multi-channel fusion recognition accuracy, time window length (TWL), command activation margin and other aspects are studied. The optimal experimental parameters are determined. Online experiments are based on the optimal test parameters of offline experiments, 8 subjects were used to study the performance of obstacle avoidance and retrieval. The online experiments achieved an average accuracy of 87.89 ± 6.62% with an ITR of 23.6 ± 4.76 bit/min. Furthermore, the rate of success in grasping three kinds of different difficulty preset targets was 61.38%.
The demand for lightweight vehicles that achieve energy conservation and emission reduction continues to grow. Aluminum alloys were commonly applied to the automotive industry to reduce the structural quality of the e...
The demand for lightweight vehicles that achieve energy conservation and emission reduction continues to grow. Aluminum alloys were commonly applied to the automotive industry to reduce the structural quality of the entire vehicle. However, the cost of aluminum alloy was higher than that of steel, so the industry considered the use of aluminum in combination with low-cost materials such as steel. Traditional welding technology was limited by the great physical difference between aluminum alloy and steel. Friction Stir Welding, a solid phase welding technology, can overcome the connection problem of aluminum and its alloys with steel, but the process parameters of FSW directly affect the welding quality. This paper established the FSW process of two different metals of DC05 and AL6061. Aimed to get a good welding joint, the error of tool speed is reduced by fuzzy PID system established in this paper, and the tool speed is controlled stably. Simulink simulation was established, and compared with the simulation results, fuzzy PID control can control the precision and stability of the tool speed of FSW, improve the welding quality, and provide a certain theoretical basis for the tool speed control.
Nonlinear energy sink (NES) has garnered significant attention since its inception due to its notable broadband vibration reduction capability. However, the introduction of strong nonlinear characteristics by NESs com...
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Nonlinear energy sink (NES) has garnered significant attention since its inception due to its notable broadband vibration reduction capability. However, the introduction of strong nonlinear characteristics by NESs complicates system responses, leading to a loss of effectiveness when the excitation force exceeds a specific threshold. Consequently, NESs have limited applicability in engineering because they are effective only within a constrained range of excitation amplitude. In this study, a compound NES (CNES) with multiple motion types is designed to extend the effective force range while maintaining broadband vibration reduction capability. The CNES is distinguished by its piecewise stiffness, collision mechanisms, and unique design of two-degree-of-freedom oscillators. The wide effective range of the CNES is demonstrated through slow linear sweep and fixed-frequency tests. The results indicate that the CNES effectively reduces vibrations in the primary oscillator (PO) with various resonant frequencies. Notably, the CNES achieves significant vibration reduction over a particularly wide range of excitation amplitude when controlling the PO with relatively high resonance frequencies (approximately 10.5 Hz and 19 Hz). However, a nonnegligible limitation of the CNES is its restricted effective range of excitation amplitude when the PO resonates at lower frequency (approximately 7 Hz). Moreover, five motion types of the CNES are identified and analyzed, with one motion type autonomously emerging in response to changes in excitation parameters, ensuring excellent vibration reduction performance across a wide excitation range. Finally, the performance of the CNES and a degraded single-degree-of-freedom CNES are compared to further demonstrate the extension effect of the multiple motion types on the effective range. The CNES can be used in scenarios where the parameters of protected systems and excitations vary widely, providing a thought to improve the NESs.
The micro-texture on the tool surface is an effective way to improve the quality of the drilling. While high-performance micro-texture plays an important role in improving the quality of working surface and prolonging...
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As one of the core mission of computer vision, object detection has been widely applied with the rapid development of computer technology, especially in the fields of face detection, behavior detection, auto driving, ...
ISBN:
(数字)9781728164168
ISBN:
(纸本)9781728164175
As one of the core mission of computer vision, object detection has been widely applied with the rapid development of computer technology, especially in the fields of face detection, behavior detection, auto driving, and intelligent monitoring. Aiming at the shortcomings of the traditional object detection, such as low detection accuracy, low efficiency and poor robustness, this article summarizes deep learning-based detectors of two kinds of modules: Anchor-Based and Anchor-Free. The performance of each detector is compared and analyzed in this paper as well. In addition, we summarize the development of object detection's key technologies from the aspect of improvement of Backbone, the optimization of NMS, imbalance of positive and negative samples' solution etc. Finally, the development trend of object detection is discussed from the prospect of lightweight detection model, weakly supervision detection and small object detection etc.
The actuation and control of mini-scale swimming robots have exhibit promising potential in limited and constrained environments, such as biomedical, micro-assembly and microfluidic applications. However, closed-loop ...
The actuation and control of mini-scale swimming robots have exhibit promising potential in limited and constrained environments, such as biomedical, micro-assembly and microfluidic applications. However, closed-loop control is still a challenging for the precision and repeatability in those applications. In this paper, a new type of soft-micro swimming robot based on magnetoelastic composite material is designed, and the swimmer can move freely on the water surface controlled by a rotating magnetic field with visual servoing. The visual feedback control strategy is proposed based on Mean Shift Algorithm and Fast Template Matching. The algorithm includes three parts: prediction, template matching, target positioning and template updating. To understand the characteristics of the swimmer, the relationship between swimming speed and magnetic field strength and frequency is verified by the algorithm in experiments. Furthermore, the proposed path following method with visual servoing applied in this controlsystem. The experimental results show that the algorithm runs fast, has high accuracy and good real-time performance, and can provide great potential in mini-scale robot applications.
Chlorophyll is a critical indicator of marine primary productivity and is essential in assessing aquatic ecosystem health. To address the limitations of current prediction models regarding accuracy, mobility, and reli...
Chlorophyll is a critical indicator of marine primary productivity and is essential in assessing aquatic ecosystem health. To address the limitations of current prediction models regarding accuracy, mobility, and reliability, this study proposes a novel Transformer-LSTM-KOA model for Chlorophyll prediction. Leveraging remote sensing data from the South China Sea, the model synergistically integrates Transformer's global analytical capabilities via self-attention and multi-head attention mechanisms with LSTM's proficiency in capturing long-term dependencies through gated mechanisms. The Kepler Optimization Algorithm (KOA) is subsequently employed to systematically optimize both global and local model parameters, thereby enhancing adaptability and robustness across diverse prediction datasets. Experimental results demonstrate superior performance with MSE and MAE values of 0.00011 and 0.00685, respectively, outperforming benchmark models. This enhanced modeling framework provides crucial technical support for marine ecological forecasting and early warning systems.
Cable-less micro-robots have exhibit great capabilities for remote applications in small and constrained environments, especially in biotechnology and healthcare. This paper presents a swimmer propelled by its undulat...
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The actuation and control of mini-scale swimming robots have exhibit promising potential in limited and constrained environments, such as biomedical, micro-assembly and microfluidic applications. However, closed-loop ...
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