Search Results (23)

Blind and visually impaired (BVI) people face significant challenges in perception, navigation, and safety during travel. Existing infrastructure (e.g., blind lanes) and traditional aids (e.g., walking sticks, basic audio feedback) provide limited flexibility and interactivity for complex environments. To solve this problem, we propose a real-time travel assistance system based on deep learning. The hardware comprises an NVIDIA Jetson Nano controller, an Intel D435i depth camera for environmental sensing, and SG90 servo motors for feedback. To address embedded device computational constraints, we developed a lightweight object detection and segmentation algorithm. Key innovations include a multi-scale attention feature extraction backbone, a dual-stream fusion module incorporating the Mamba architecture, and adaptive context-aware detection/segmentation heads. This design ensures high computational efficiency and real-time performance. The system workflow is as follows: (1) the D435i captures real-time environmental data; (2) the processor analyzes this data, converting obstacle distances and path deviations into electrical signals; (3) servo motors deliver vibratory feedback for guidance and alerts. Preliminary tests confirm that the system can effectively detect obstacles and correct path deviations in real time, suggesting its potential to assist BVI users. However, as this is a work in progress, comprehensive field trials with BVI participants are required to fully validate its efficacy. Full article

This paper presents the design and development of a new modular wall-climbing robot—Modular Wall Climbing-1 (MC-1)—for solving the problem of autonomous wall switching observed in wall-climbing robots. Each modular robot is capable of independently adhering to vertical surfaces and maneuvering, making it a fully autonomous robotic system. Multiple modules of MC-1 are connected by an electromagnet-based magnetic attachment method, and wall transitions are achieved using a servo motor mechanism. Moreover, an ultrasonic sensor is employed to measure the unknown wall-inclination angle. Mechanical analysis is conducted for MC-1 at rest individually and in combination to determine the required suction force. Experimental investigations are performed to assess the robot’s crawling ability, loading capacity, and wall-transition performance. The results demonstrate that the MC-1 robot is capable of multi-angle wall transitions for executing multiple tasks. It provides a new approach for wall-climbing robots to collaborate during wall transitions through a quick attachment-and-disassembly device and an efficient wall detection method. Full article

In response to the situation in the Huanghuai region, where corn fertilization and pesticide application primarily rely on manual methods such as hand broadcasting fertilizer and using manual backpack sprayers, resulting in low levels of mechanization, this study designed an electric integrated work vehicle in line with the trend of developing new energy. The vehicle is powered by six 12 V, 100 Ah lead-acid batteries and integrates the functions of fertilization and pesticide spraying. It can achieve precise hole-fertilization, applying fertilizer to a depth of 100 to 150 mm near the roots of corn, and can also perform multi-row pesticide spraying. The vehicle’s electronic control system is divided into two functional areas: 220 V and 24 V. The walking system uses a 220 V, 2 kW AC servo motor, which is driven by converting the voltage of the 72 V battery group into a 220 V sine wave AC through an inverter, and the motor speed can be adjusted. The working width is adjusted by two fixed electric cylinders at the top of the rear wheel frame. The user can preset the width through the control panel, and during operation, the electric cylinders can be automatically controlled to the optimal working width via a whisker-type limit switch. Analysis using ADAMS software shows that when the vehicle speed is 2, 3, and 5 km per hour, the opening angles of the duckbill controller are 66°, 58°, and 48°, respectively, indicating that the higher the speed, the smaller the opening angle. This shortens the fertilization interval time and makes the fertilization spacing more stable. The maximum opening angle of the adjacent duckbill is 25°, indicating that the fertilization amount remains stable. When the vehicle is moving in reverse, the duckbill always remains closed, and at different speeds, the opening angle change curve of the duckbill controller is smooth and regular. This vehicle significantly improves the efficiency and precision of corn planting. However, improvements are still needed in battery technology, control system optimization, and the high cost of electric agricultural machinery to promote the widespread application of agricultural mechanization. Full article

In order to solve the problems of frequent pressure fluctuations caused by frequent action of the unloading valve of the pump station and serious hydraulic shock due to the variable amount of fluid used in the hydraulic support system of the coal mining face and the irregularity of the load suffered by the system, a pump–valve cooperative multi-mode stabilizing control method based on a digital unloading valve was proposed. Firstly, a prototype of a digital unloading valve under high-pressure and high water-based conditions was developed, and a digital control scheme was proposed to control the pilot valve by a servo motor to adjust the system pressure in real time. Then, an experimental platform for simulating the hydraulic bracket and a co-simulation model was constructed, and the validity of the co-simulation model was verified through experiments. Secondly, a collaborative multi-mode pressure stabilization control method for the pump valve based on a GRNN (General Regression Neural Network) was established to control the flow and pressure output of the emulsion pumping station according to the actual working conditions. Finally, numerical research and experimental verification were carried out for different working conditions to prove the effectiveness of this method. The results showed that the proposed pressure stabilization control method could adaptively adjust the working state of the digital unloading valve and the liquid supply flow of the emulsion pump station according to the working condition of the hydraulic support, effectively reducing the frequency and amplitude of the system pressure fluctuations and making the system pressure more stable. Full article

This paper introduces an extended state observer-based command filtered backstepping control method to improve the tracking accuracy and synchronization performance of multi-motor-driving servo systems under the condition of low-speed nonlinear friction dynamics. Firstly, a novel and effective four-motor synchronization scheme is designed and various groups of synchronization feedback signals are introduced to achieve accurate synchronization performance among motors. Then, the observer is designed to estimate the friction torque. And the controller is developed via command filtered backstepping technique to avoid additional computational complexity, making the control signals suitable for practical application. Finally, the stability of the closed-loop system is analyzed, and the tracking and synchronization performance is verified through designed experiments. Full article

Dimensional and profile measurements of deep-hole parts are key processes both in manufacturing and product lifecycle management. Due to the particularity of the space conditions of deep-hole parts, the existing measurement instruments and methods exhibit some limitations. Based on the multi-axis, highly precise servo drive system, a novel measuring device is developed. The laser displacement sensors are fed by the flux-switching permanent magnet linear motor, and the part is rotated by the servo motor. On this basis, the assessment methods of roundness, straightness, and cylindricity are proposed by employing the least square method (LSM). Additionally, considering the axial center deviation between the sensors and the part, the rotating center coordinate is optimized by the gradient descent algorithm (GDM). Then, the measurement system is constructed and the experiment study is conducted. The results indicate favorable evaluation error of the LSM fitting and GDM iteration. Compared with the coordinate measuring machine (CMM), the measured results show good consistency. In the error analysis, the angle positioning error of measured point is less than 0.01°, and the axial positioning error is less than 0.05 mm. The proposed system and assessment method are regarded as a feasible and promising solution for deep-hole part measurements. Full article

Multi-motor servo systems are widely used in industrial control. However, the single-core microprocessor architecture based on the microcontroller unit (MCU) and digital signal processor (DSP) is not well suited for high-performance multi-motor servo systems due to the inherent limitations in computing performance and serial execution of code. The bus-based distributed architecture formed by interconnecting multiple unit controllers increases system communication complexity, reduces system integration, and incurs additional hardware and software costs. Field programmable gate array (FPGA) possesses the characteristics of high real-time performance, parallel processing, and modularity. A single FPGA can integrate multiple motor servo controllers. This research uses MCU + FPGA as the core to realize high-precision multi-axis real-time control, combining the powerful performance of the MCU processor and the high-speed parallelism of FPGA. The MCU serves as the central processor and facilitates data interaction with the host computer through the controller area network (CAN). After data parsing and efficient computation, MCU communicates with the FPGA through flexible static memory controller (FSMC). A motor servo controller intellectual property (IP) core is designed and packaged for easy reuse within the FPGA. A 38-axis micro direct current (DC) motor control system is constructed to test the performance of the IP core and the heterogeneous embedded platforms. The experimental results show that the designed IP core exhibits robust functionality and scalability. The system exhibits high real-time performance and reliability. Full article

Pointing accuracy is a crucial performance index for a fully steerable large-aperture radio telescope and is subject to external and internal disturbances. Improvement of the antenna’s servo control performance is meaningful for pointing, especially for blind pointing of the antenna. This paper firstly establishes a multi-motor-driving four-degrees-of-freedom (DOF) model of an antenna servo system, then optimizes the original design consisting of the active disturbance rejection (ADR)-based velocity controller and lead–lag-based position controller, making the velocity controller a novel linear ADR-based controller coupled with a disturbance-velocity compensation (DLADRC) and the position controller the simplest proportional (P) controller. Simulation results based on a 100 m class radio telescope servo model indicate that the new control system’s velocity-loop response is smoother, the position-loop peak disturbance response is reduced by 17.8%, the position-loop dynamic performance with the short settling time and slight overshoot remains the same as the former PD-LADRC system, and the RMS pointing/tracking error is 2.16 arcsec under a mean wind of 3 m/s, less than the design specification of 2.5 arcsec RMS required. Full article

This paper presents a biomimetic fish robot featuring a flexible spine driven by cables, which integrates the cable-driven mechanism with a flexible spine. The drive system separates the body and tail fin drives for control, offering enhanced flexibility and ease in achieving phase difference control between the body and tail fin movements compared to the conventional servo motor cascaded structure. A prototype of the biomimetic fish robot was developed, accompanied by the establishment of a kinematic model. Based on this model, a control method for the biomimetic fish is proposed. Additionally, we introduce the concept of prestress to establish a numerical model for the biomimetic fish. Using multi-physical field simulation software, we simulate the two-dimensional autonomous swimming process of the biomimetic fish under different flapping frequencies and solve for its swimming characteristics as well as hydrodynamic properties. Both the simulation and experimental results validate the accuracy of our kinematic model. Full article

Solid-state LiDAR offers multiple advantages over mechanism mechanical LiDAR, including higher durability, improved coverage ratio, and lower prices. However, solid-state LiDARs typically possess a narrow field of view, making them less suitable for odometry and mapping systems, especially for mobile autonomous systems. To address this issue, we propose a novel rotating solid-state LiDAR system that incorporates a servo motor to continuously rotate the solid-state LiDAR, expanding the horizontal field of view to 360°. Additionally, we propose a multi-sensor fusion odometry and mapping algorithm for our developed sensory system that integrates an IMU, wheel encoder, motor encoder and the LiDAR into an iterated Kalman filter to obtain a robust odometry estimation. Through comprehensive experiments, we demonstrate the effectiveness of our proposed approach in both outdoor open environments and narrow indoor environments. Full article

The linear motor feeding system is a typical electromechanical coupling system. Conventional characteristic analyses of electromechanical coupling often overlook the influence of flexible deformation in critical components of the linear motor feeding system. Moreover, when employing genetic algorithms to optimize servo system PID control parameters, slow convergence, nonconvergence, or premature convergence problems may arise. To address these issues, this paper proposes a new performance optimization method for a linear motor feeding system. The method uses a combination of “multi-body theory + finite element” to accurately account for the flexible deformation of critical components of the feeding system, establishes a rigid–flexible electromechanical coupling model of the linear motor feeding system, and optimizes the PID parameters of the established model with an improved adaptive genetic algorithm. Simulation results demonstrate that, when utilizing an adaptive genetic algorithm to optimize the rigid–flexible electromechanical coupling model and a control system model that disregards flexible body deformation, the system achieves stability in 0.02 s and 0.027 s with overshoots of 13% and 27%, respectively. These outcomes confirm the accuracy and importance of considering flexible body deformation in the optimization performance of a linear motor feeding system. At the same time, the time required to reach the steady state of the rigid–flexible electromechanical coupling model optimized by the adaptive genetic algorithm is shortened from 0.035 s to 0.02 s. The sinusoidal signal response curve of the optimized system does not exhibit any peak overshoot compared with that of the nonoptimized system, and the response speed is also faster. These results demonstrate the effectiveness of the rigid–flexible electromechanical coupling model optimized by the nonlinear adaptive genetic algorithm. The displacement response curves of the linear motor feeding system under different workbench loads are obtained through experiments and compared with those obtained from simulations to verify the established model and the correctness of the proposed method. Full article

The Lunar Gravity Compensation Facility (LGCF) is a critical component in ground tests for a crewed lunar roving vehicle (CLRV). The track-following servo subsystem’s performance is of critical importance in the LGCF, as it needs to achieve high-precision tracking of the CLRV’s fast, wide range of motion in the horizontal direction. The subsystem must also operate within various constraints, including those related to speed, acceleration, and position. These requirements introduce new challenges to both the design and control of the subsystem. To tackle these challenges, this paper employs a Permanent-Magnet Synchronous Motor (PMSM) vector control method based on Space Vector Pulse Width Modulation (SVPWM) to achieve accurate speed tracking. Additionally, this paper presents an Explicit Model Predictive Control (EMPC) strategy for precise position servo control of the track-following system under multi-parameter constraints. The simulation model of the track-following servo subsystem is established based on the above methods. The simulation results demonstrate that the position tracking error of the gravity compensation system, constructed using the above method combined with EMPC control, is less than 0.2 m. The control performance of the EMPC is significantly better than those of the PI and LQI controllers. The influence of errors on the drawbar pull is within 12.5%, and its effect on the compensation force is negligible. These results provide theoretical support for the design of a track-following servo subsystem. Full article

This paper presents a servo control method for the multiple launch rocket system (MLRS) launcher during marching fire operations. The MLRS, being a complex nonlinear system, presents challenges in designing its servo controller. To address this, we introduce the fuzzy adaptive sliding mode control (FASMC) approach. The permanent magnet synchronous motor (PMSM) and controller of the MLRS were simulated in the MATLAB/Simulink environment. The dynamic model of the MLRS during marching fire was established using multi-body system theory, vehicle mechanics, and launch dynamics. The dynamic model was then integrated with the FASMC-based controller using the Adams/View module. Numerical calculations were performed to demonstrate the control performance and the effectiveness and applicability of the proposed approach were validated through a comparison experiment between FASMC and other common control methods. Full article

The multi-axis servo control system has been extensively used in industrial control. However, the applications of traditional MCU and DSP chips in high-performance multi-axis servo control systems are becoming increasingly difficult due to their lack of computing power. Although FPGA chips can meet the computing power requirements of high-performance multi-axis servo control systems, their versatility is insufficient, and the chip is too costly for large-scale use. Therefore, when designing the universal SoC, it is better to directly embed the coprocessor IP core dedicated to accelerating the multi-motor vector control current loop operation into the universal SoC. In this study, a coprocessor IP core that can be flexibly embedded in a universal SoC was designed. The IP core based on time division multiplexing (TDM) technology could accelerate the multi-motor vector control current loop operation according to the hardware–software coordination scheme proposed in this study. The IP was first integrated into a universal SoC to verify its performance, and then the FPGA prototype verification for the SoC was performed under three-axis servo control systems. Secondly, the ASIC implementation of the IP was also conducted based on the CSMC 90 nm process library. The experimental results revealed that the IP had a small area and low power consumption and was suitable for application in universal SoC. Therefore, the cheap and low-power single universal SoC with the coprocessor IP can be suitable for multi-axis servo control. Full article

Carbon fiber-reinforced composites represent a broadly utilized class of materials in aeronautical applications, due to their high-performance capability. The studied CFRP is manufactured from a 3K carbon biaxial fabric 0°/90° with high tensile resistance, reinforced with high-performance thermoset molding epoxy vinyl ester resin. The macroscale experimental characterization has constituted the subject of various studies, with the scope of assessing overall structural performance. This study, on the other hand, aims at evaluating the mesoscopic mechanical behavior of a single-ply CFRP, by utilizing tensile test specimens with an average experimental study area of only 3 cm². The single-ply tensile testing was accomplished using a small scale custom-made uniaxial testing device, powered by a stepper motor, with measurements recorded by two 5-megapixel cameras of the DIC Q400 system, mounted on a Leica M125 digital stereo microscope. The single-ply testing results illustrated the orthotropic nature of the CFRP and turned out to be in close correlation with the multi-ply CFRP tensile and bending tests, resulting in a comprehensive material characterization. The results obtained for the multi-ply tensile and flexural characteristics are adequate in terms of CFRP expectations, having a satisfactory precision. The results have been evaluated using a broad experimental approach, consisting of the Dantec Q400 standard digital image correlation system, facilitating the determination of Poisson’s ratio, correlated with the measurements obtained from the INSTRON 8801 servo hydraulic testing system’s load cell, for a segment of the tensile and flexural characteristics determination. Finite element analyses were realized to reproduce the tensile and flexural test conditions, based on the experimentally determined stress–strain evolution of the material. The FEA results match very well with the experimental results, and thus will constitute the basis for further FEA analyses of aeronautic structures. Full article