This paper presents a low-frequency vibration energy harvester based on a magnetic spring and a rolling magnet, designed to harvest energy from human motion and low-frequency mechanical vibrations. A theoretical model is established and numerically analyzed to investigate the dynamic and output characteristics, enabling the optimization of the rolling magnet dimensions and structural parameters. A prototype is fabricated and experimentally characterized under different excitation frequencies and amplitudes. The results show that a maximum output is achieved at an amplitude of 20 mm and a frequency of 6 Hz, with an RMS voltage of 8.17 V and an output power of 6.36 mW. In the frequency range of 3 6 Hz, the voltage frequency amplification factor ranges from 6.13 to 9.33, with an average value of 8.15. Application tests demonstrate that the prototype can successfully harvest kinetic energy from human body movements to power a Xiaomi temperature and humidity sensor, and when mounted on a bicycle, it captures road-induced vibrations to illuminate a LED panel consisting of 26 lights. These results confirm the feasibility of the proposed harvester for powering low-power electronics.

In this paper, an airflow energy harvester based on diamagnetic levitation is investigated to optimize the floating magnet configuration for enhanced energy conversion and harvesting performance. The influence of the notch radius of the floating magnet on its rotational characteristics is analyzed through simulation, leading to an improved structural design with the floating magnet encapsulated by a resin housing. Comparative simulation and experiment are conducted on the airflow energy harvester before and after the improvements. The results demonstrate that the corresponding steady-state levitation gap at the same upper spacing increases. The housing does not affect the energy conversion coefficient, and both the rotational speed of the combined floating magnet and the induced electromotive force (EMF) generated in the coils increase as the housing's external notch radius decreases. At an airflow rate of 3000 sccm through both nozzles, the improved harvester yields an average peak voltage of 3.463 V, an effective voltage of 2.449 V, and an average harvested power of 237.94 mW without an external circuit. The optimal output power is 112 mW, with a power density of 1.2556 mW/cm3, and an energy conversion efficiency of 28.96%. 60 LEDs are illuminated by the improved energy harvester, verifying its application feasibility.

The vibration energy harvester based on diamagnetic levitation can increase the amplitude of the floating magnet by adjusting the natural frequency of the diamagnetic levitation structure. However, due to size constraints, the floating magnet frequently collides with the shell. To collect the energy generated by the collision and improve the output performance of the harvester, we introduce piezoelectric cantilever beams into the shell of the vibration energy harvester. The piezoelectric cantilever beam comprises a structural layer, a piezoelectric layer (PZT-5H) and a seismic block. This structure exhibits high energy density and excellent structural stability. The collision provides the initial velocity for the vibration of the piezoelectric cantilever beam, thereby enhancing its output voltage. The simulation results show that collision between the floating magnet and the shell can increase the output voltage of the piezoelectric cantilever beam by more than 10 times. Experimental results show that when the resonance frequency is 3.8 Hz and the external amplitude is 5 mm, the effective output voltage of the piezoelectric cantilever beam is 3034 mV, and the error between the simulation and experiment results is 8.7%. Following the addition of piezoelectric cantilever beams, the output performance of the vibration energy harvester is increased by 7.15 times. This research provides an effective solution for collecting energy generated by impacts and collisions.

In this paper, an array of permanent magnets is proposed as a floating magnet to enhance the levitation characteristics of the diamagnetic levitation structure. Experimental results show that the maximum steady levitation gap of the diamagnetic levitation structure can be increased by 80.21% with the new floating magnet, and the axial size of the diamagnetic levitation structure can be reduced by up to 39.73%. A prototype of a vibration energy harvester based on the diamagnetic levitation structure was constructed. The experimental results show that when the external excitation frequency is 4.8 Hz and the amplitude is 6 mm, the maximum effective voltage of the vibration energy harvester is 1663 mV. Compared with the original structure, the output performance of the vibration energy harvester is improved by 33.87%. This study shows that using this permanent magnet array as a floating magnet not only improves the levitation characteristics of the diamagnetic levitation structure, but also enhances the output performance of the vibration energy harvester.

In this paper, the levitation characteristics of the floating magnet in an airflow energy harvester based on diamagnetic levitation structure is studied by theoretical analysis and simulation calculation. According to the simulation with COMSOL Multiphysics, we obtained the relationship between the inductive voltage and the values of the notch radius, the floating magnet radius and the floating magnet thickness. At the same time, the coil parameters, including inner diameter, outer diameter, wire diameter and coil layer, were analyzed to study the influence of energy conversion factor (ECF) and energy conversion efficiency of the airflow energy harvester. Based on the analysis results, corresponding parameters are selected for experiment. And the results show that the peak voltage is 1.892 V, and the average power is 94.70 mW when the left and right nozzles’ gas flow rate is 3000 sccm. The simulation analysis provides a good reference for parameters selection of the floating magnet and the coil in the diamagnetic airflow energy harvester, which can increase the energy harvesting efficiency of the harvester.

During the operation of outdoor heavy-duty Automated Guided Vehicle (AGV), the stability and safety of AGV are easily reduced due to load transfer. In order to solve this problem, a trajectory tracking control strategy considering load transfer is proposed to realize the trajectory tracking of AGV and the adaptive distribution of driving torque. The three-degree-of-freedom (3-DOF) kinematics model and pose error model of heavy-duty AGV vehicles are established. The lateral load transfer and longitudinal load transfer rules are analyzed. The vehicle trajectory tracking control strategy is composed of an improved model predictive controller (IMPC) and drive motor torque adaptive distribution controller considering load transfer. By optimizing the lateral acceleration of the vehicle body, the IMPC controller improves the problem of large driving force difference between the left and right sides of the wheel caused by the lateral transfer of the load and the problem of large wheel adhesion rate caused by the longitudinal transfer of the load is improved by the speed controller and the torque proportional distribution controller. The joint simulation platform of MATLAB/Simulink and CarSim is built to simulate and analyze the trajectory tracking of heavy-duty AGV under different pavement adhesion coefficients. The simulation results have shown that compared with the control strategy without considering load transfer, on the two types of pavements with different adhesion coefficients, the maximum lateral acceleration is reduced by 19.7%, and the maximum tire adhesion rate is reduced by 11.5%.

This paper proposes an airflow energy harvester based on dual-pull diamagnetic levitation with a center-symmetric rotor, aiming to investigate its levitation stability and energy harvesting efficiency. Simulation calculations were performed to analyze how the coil’s and symmetrical rotor’s structural parameters affect the harvester’s levitation and output characteristics, thereby determining the coils’ appropriate layout and structural parameter. Subsequently, the influence of the thickness and notch radius of the symmetrical rotor on the levitation characteristics and output performance of the airflow energy harvester was analyzed by experiment. Simulation and experimental results indicate that a 4-mm-thick symmetrical rotor with a 2.5-mm notch radius is identified as the most suitable choice in the study. When left and right nozzles maintain an airflow rate of 3000 sccm, the stable rotational speed of the symmetrical rotor is 25,827 rpm, the peak output voltage of the airflow energy harvester is 3.206 V, and the power of the airflow energy harvester is 383.52 mW. The optimal external load for this airflow energy harvester is 13.4 Ω. With the load circuit connected, the total power of the airflow energy harvester is 191.76 mW, and the maximum power of the external load circuit is 95.88 mW. In practical application experiment, 60 LED lights were successfully illuminated, verifying the feasibility of the airflow energy harvester.

Traditional contact-separation mode triboelectric nanogenerators (CS-TENGs) and lateral sliding mode TENGs exhibit distinct strengths and weaknesses in terms of their charge generation capability and durability. In this study, by leveraging a bistable compliant mechanism (BHM-TENG), we propose a hybrid mode TENG, which synthesizes the features of two traditional working modes to achieve both high durability and satisfactory performance. The proposed design exhibited a 78.6% surge in voltage output and a 142% surge in power density compared to CS-TENG. The design also maintains over 95% power generation capability after 100 000 cycles. Moreover, the compliant bistable mechanism offers a reliable actuation method at low frequencies, validated through experiments supported with a mathematical model. Real-world energy harvesting applications enabled by BHM-TENG are also discussed.

The commonly-used single vision lens has the problem of variational refractive power when it is worn and actually perceived.Response to this problem,a new design method based on lens-eye joint model for single vision lens was proposed.According to the new design method,the variational visual angles were matched to different areas of lens,and the constant perceived diopter on the corneal surface was set as precondition.The diopter on the lens surface was recomputed,and finally the diopter distribution and the corresponding surface shape data were obtained.Based on the proposed design method,the diopter of-6.00 D actually felt on the corneal surface was taken as an example to generate surface shape data for lens manufacturing,and the surface shape and diopter of the manufactured lens were measured and evaluated.The test results show that the central diopter of the manufactured lens is-6.30 D,the diopter values gradually vary from the center to the edge of the manufactured lens,and the maximum diopter error is smaller than±0.23 D,which verifies the effectiveness of the proposed designed method.

In order to solve the defect that the intrinsic frequency ω 0 of the diamagnetic levitation electromagnetic vibration energy harvester cannot be adjusted, a pulling magnet with downward attraction to the floating magnet is added below the floating magnet of the original structure. The simulation found multiple ω 0 exist in the structure with the pulling magnet, and the relationship between ω 0 and the vertical distance L L from the lifting magnet’s lower surface to the floating magnet’s upper surface is determined. It is found that ω 0 can be varied from 2.36 to 12.3 Hz by adjusting L L . The dynamic characteristics of the floating magnet is studied to obtain its amplitude-frequency curve. The output performance of the energy harvester at different ω 0 is calculated and the simulation results are well verified experimentally. The experiments show that the effective voltages can all reach their maximum after arranging the induction coil when the excitation frequency is from 2.2 to 6.1 Hz. The frequency band width for effective voltages greater than 400 mV is made up to 7.6 Hz. The maximum effective voltage of the structure with the pulling magnet is 749 mV, which is 1.98 times larger than the structure without a pulling magnet; the maximum power is 779 µW, which is 7.9 times larger than the structure without a pulling magnet. Experiments show that the structure with the pulling magnet not only significantly broadens the effective bandwidth of the energy harvester, but also significantly improves the output performance of the energy harvester. In addition, the nonlinear characteristics of the system make it possible to obtain good output performance even when the vibration frequency is far from ω 0 .

In order to improve the energy harvesting efficiency of airflow energy harvester based on diamagnetic levitation, structure parameters and position relationships between the coils and the floating magnet were investigated theoretically and experimentally. The output performance of the energy harvester was conducted, and the concept of energy conversion factor was proposed and defined. Seven control variables affecting the peak-induced electromotive force generated by the coils were analyzed using the Taguchi method. The result shows that all seven control factors are significantly related to the peak-induced electromotive force. Among them, the percentage contribution of the notch radius of the floating magnet is 69.17%, so it is the most significant factor. Further research on the notch radius of the floating magnet was carried out to obtain the important conclusion that the energy conversion factor is maximum when the ratio of the floating magnet's surface area to the notches' surface area is approximately 2:1. According to the experimental results, for the floating magnet with 9 mm radius, the airflow energy harvester has the maximum energy conversion factor when its notch radius is 3.8 mm, and the variation trend of experimental results is basically consistent with that of simulation results. This study could provide a valuable reference for designing the diamagnetic levitation airflow energy harvester with optimal energy harvesting efficiency.

针对机器人手动示教存在的精度不稳定、编程时间长、机器人工作效率低的问题,研究基于MATLAB的离线仿真系统.采用MATLAB编程实现了机器人三维模型的控制和仿真,解析获得机械臂在实际工作时的控制语言,生成相应的控制程序从而实现虚拟和现实中六自由度机器人的控制.最后,以电芯涂胶工作单元作为原型来搭建相应的虚拟工作环境,并在实际中以库卡公司的KR16验证离线仿真系统的有效性,证明该系统可以出色完成涂胶任务.

研究了一种推挽式抗磁悬浮结构.通过对其悬浮特性的研究,探索了其在能量采集器领域的应用潜力.使用MATLAB进行数值仿真发现,提升磁铁和悬浮磁铁的间距LL存在一个变化范围,悬浮磁铁可以在该范围内的任意一点稳定悬浮,具有悬浮点可调的特点.基于轴向合力和轴向势能研究了悬浮磁铁的悬浮特性随着LL的变化趋势,结果表明该结构的悬浮点、最大单稳悬浮空间和轴向磁弹簧刚度均可调节.基于该抗磁悬浮结构搭建了气流能量采集器样机,当气体体积流量为3 000 mL/min时,可以采集并输出1.924 V的峰值电压和90.25 mW的输出功率,能量采集器的输出性能有了明显提升,可以为无线传感网络中的传感节点供电.同时,该结构在执行器和传感器等领域也具有良好的应用潜力.

This paper presents an improved solution for the airflow energy harvester based on the push-pull diamagnetic levitation structure. A four-notch rotor is adopted to eliminate the offset of the floating rotor and substantially increase the energy conversion rate. The new rotor is a centrally symmetrical-shaped magnet, which ensures that it is not subjected to cyclically varying unbalanced radial forces, thus avoiding the rotor's offset. Considering the output voltage and power of several types of rotors, the four-notch rotor was found to be optimal. Furthermore, with the four-notch rotor, the overall average increase in axial magnetic spring stiffness is 9.666% and the average increase in maximum monostable levitation space is 1.67%, but the horizontal recovery force is reduced by 3.97%. The experimental results show that at an airflow rate of 3000 sccm, the peak voltage and rotation speed of the four-notch rotor are 2.709 V and 21,367 rpm, respectively, which are 40.80% and 5.99% higher compared to the three-notch rotor. The experimental results were consistent with the analytical simulation. Based on the improvement, the energy conversion factor of the airflow energy harvester increased to 0.127 mV/rpm, the output power increased to 138.47 mW and the energy conversion rate increased to 58.14%, while the trend of the levitation characteristics also matched the simulation results. In summary, the solution proposed in this paper significantly improves the performance of the airflow energy harvester.

In this article, a new diamagnetic levitation structure is proposed to explore its potential in the application of sensors and actuators through the study of its levitation and dynamic characteristics. Compared with our old diamagnetic levitation structure, the levitation point, maximum monostable levitation space, horizontal magnetic spring stiffness, and axial resultant force distribution of the new structure are all adjustable. At the same time, the maximum horizontal radial recovery force of the floating magnet could reach 34 $780\, \mu \text{N}$ , which is 542.41% higher than that of the floating magnet in the old structure. Accordingly, when the range of the horizontal radial displacement is 0–15 mm, the maximum axial resultant force of the floating magnet is $439.7 \,\mu \text{N}$ , which is only 5.72% of that in the old structure. In the experiment, when the floating magnet is blown by nitrogen gas with a flow rate of 3000 sccm, the maximum horizontal radial displacement of the floating magnet is 2.27 mm, which is only 22.976% of that in the old structure. Under the same gas flow rate, the maximum tilt angle of the floating magnet is 0.482°, which is only 3.998% of that in the old structure. In summary, the theoretical analysis, numerical simulation, and experiment results are consistent with each other, which indicates the great potential of the new structure in the application of sensors and actuators.

The commonly used correction methods of ametropia are all focused on correcting a certain static value of human-eye aberration;however,these methods cannot effectively correct the dynamic changes in human-eye aberration.To solve this problem,a dynamic compensation system is developed to correct the eye's defocusing of humans based on image processing.The system consists of a dynamic measurement system for pupil size composed of an infrared camera and an image processing program,and a dynamic correction system for refractive power composed of a transmission deformable mirror and a control program as the core.The system prototype is built on the optical experimental platform,where the corresponding experiments are performed.The results show that the system can assess the accurate measurement of the pupil size and ensure an accurate,fast,and smooth correction of the corresponding defocus aberration under different light intensities,thereby preliminarily confirming the feasibility and effectiveness of the proposed method and system.

In this paper, the proposed diamagnetic levitation structure was studied to explore its potential in energy harvesting. It is proved that the floating magnet rotor can be levitated stably under the joint action of two highly oriented pyrolytic graphite (HOPG) sheets and the lifting magnet. Simulation calculation was carried out to analyze the influence of different coil radius and wire diameter on peak voltage and average power in scheme A or scheme B, so as to obtain appropriate layout and wire diameter for the coils which was built the experimental platform. Subsequently, the center hole, notch radius and thickness of the floating rotor are analyzed by experiment. And the influence of different parameters on rotation speed of the rotor and peak output voltage of coils is obtained. Through experimental results, it is found that the notch radius of the floating rotor has the greatest influence on the rotation speed of the rotor. Based on the experiment, a new-type rotor was designed, with an outer shell to reduce the notch radius. Compared with the original floating rotor, there was 49.73% increase in voltage, 55.70% increase in rotation speed and 124.50% increase in power according to the experimental results. Test was performed with the optimization, the LED array of Zhengzhou University logo, which was composed of 60 LED lights, was lighting up. According to the oscilloscope measurement, the diamagnetic levitation energy harvester has an output voltage up to 1.294 V and average power of 60.67 mW under gas flow rate of 3000 sccm and nozzle exit velocity of 6.173 m/s. Obviously, the new-type rotor proposed in this paper could significantly increase the energy conversion efficiency, and make the future application of airflow energy harvester a step further.

In this article, an airflow energy harvester based on a push–pull diamagnetic levitation structure with double stabilizing magnets is proposed to explore its energy harvesting efficiency and environmental adaptability. The static and dynamic mechanical characteristics of the floating magnet are studied. Then, three structure parameters resulting in the change of energy conversion factor (ECF) are analyzed using COMSOL software. A platform was constructed to carry out experiments, and the results are as follows. First, when both the air flow rates from left nozzle ( ${Q}_{\text {NL}}$ ) and the air flow rate from right nozzle ( ${Q}_{\text {NR}}$ ) are 3000 sccm, the average peak voltage (APV) is 1.924 V, the average power (AP) is 97.93 mW and the energy conversion ratio (ECR) is 41.12%. Second, when ${Q}_{\text {NL}}$ is 3000 sccm and ${Q}_{\text {NR}}$ is 2000 sccm, the APV is 1.245 V, the AP is 41.01 mW, and the ECR is 26.57%. Third, when ${Q}_{\text {NL}}$ is 3000 sccm and ${Q}_{\text {NR}}$ is 0 sccm, the APV is 0.666 V, the AP is 11.68 mW, and the ECR is 9.82%. The experimental results show that it is feasible and performs well in a real-life situation, which is a major step toward the application as an energy harvester.

This paper proposes a novel piezoelectric energy harvester attached with a trailing-edge flap under various installation angles, for enhancing the aeroelastic vibration and improving the harvesting performance. The mathematical models of the fluid-structure-electric coupled fields are derived, the simulation models of the multi-physical coupled fields of the harvester system with various installation angle flaps are established, and the experimental prototypes of the harvester are fabricated. The influences of the flap installation angles on the flow field and output characteristics are investigated theoretically, numerically, and experimentally. The results demonstrate that the flap stiffness and damping coefficients exert less influence on vibration characteristics and harvesting performance. The flap at a certain installation angle alters the flow field, affects the flow pattern, restricts the vortex shedding, and offsets the aerodynamic force and moment. A decrease in the flap installation angles results in increasing the vibration response and output performance. The obtained numerical results are in good agreement with the experimental and theoretical values, which verifies the effectiveness of the simulation model. The maximum plunge amplitude is 0.029 m and the output voltage is 15.51 V at 17.74 m/s and an installation angle of 0o. The enhancement ratio of the output voltage at 0o is up to 148.6% over 45o, which achieves better harvesting performance. The designed harvester system powers indirectly the pedometer for 104 s at 13.58 m/s. This research offers an essential foundation for achieving better tradeoffs in energy harvesting and vibration suppressing by appropriately selecting the flap installation angle.

对抗磁悬浮气流能量采集器的悬浮转子的悬浮特性进行分析,选定合适的悬浮间距后分析了优化前后两种不同的线圈布置方式和线圈结构参数对输出特性的影响.使用COMSOL5.5进行有限元仿真分析,发现感应电压和平均功率随着线圈外径的增大表现出先增大后减小的特性,找到输出电压最高时线圈的布置方式及结构参数,最终确定线圈外径6 mm,导线直径0.02 mm,匝数为600匝,在2 000 r/min时采集器得到了 2.33 V的峰值电压和0.32 mW的电源平均功率.