Traditional multipoint hybrid maglev systems cannot realize the zero-power horizontal levitation state under eccentric load, which means the steady-state current is zero, and the air gap of each magnet is equal. This article proposes a new maglev system with two rotary magnets to solve this problem. The two magnets can move on an annular guideway to counteract the moment caused by the eccentric load. At first, we established the linear parameter varying model of this maglev system. Then, the control strategy is designed, which consists of a zero-power horizontal levitation controller and rotation controller. The levitation control is realized by introducing feedback of integral current and deviation of air gap in the proportional-derivative control system. The rotation controller employs a centroid observer and centroid Jacobian. It outputs the rotating angle at the demand of the zero-power and horizontal levitation. Experimental results demonstrate that the proposed maglev system has a better zero power and horizontal levitation performance than without rotary magnets. The direction of the air gap variation is opposite to that of the loading direction. The variation size of air gap length depends on the load weight, whereas rotation angle is related to the load weight and loading position.

This paper focuses on the analysis of the quasi-zero power characteristic for a permanent magnetic levitation system with a variable flux path control mechanism. The system mainly consists of a disk permanent magnet, a pair of yokes, and a rotary actuator. The permanent magnet magnetized diametrically is rotated by the actuator, which can achieve the control of the levitation force by changing the flux. Unlike the electromagnetic system, the input to the actuator is used to maintain the rotation angle corresponding to the equilibrium position, not to directly produce a magnetic force. Therefore, the proposed system possesses a lower power consumption. Analysis of mechanism, current model, and different levitation control strategies are presented in this paper. With the variable air gap length control and the constant air gap length control, the permanent magnetic levitation system performs well in levitation with quasi-zero power in loading experiments. The constant air gap control is demonstrated to possess higher safety when the levitation mass is changed, which has the potential for magnetic levitation transportation.

The variable-stiffness joint (VSJ) plays an important role in creating compliant and powerful motions. This paper presents a novel wire-driven VSJ based on a permanent magnetic mechanism (PMM). The proposed joint regulates the joint stiffness with lower energy consumption through a wide range via the permanent magnetic mechanism. This effect possibly depends on the novel nonlinear combination of a permanent magnet-spring and wire-driven system that achieves the same stiffness with lower wire tension. A trapezoidal layout of the joint is proposed. Because of the relationship among the stiffness, the position of the joint and the stiffness of the PMM, the stiffness model is also been established. Based on this model, the decoupling controller is built to independently control the position and stiffness of the joint. Experiments show that the VSJPMM achieves position and stiffness independently and also reduces energy and power required to regulate the stiffness compared with the traditional approach. In addition, the proposed mechanism displays a powerful motion and short stiffness adjustment time.

Aiming at the efficiency and precision in micro electrical discharge machining (micro-EDM) is affected because the interpole voltage is unstable in conventional micro-EDM. This paper describes a five-degrees-of-freedom (5-DOF) controlled, wide-bandwidth, and high-precision magnetic levitation actuator. The conventional micro-EDM can install the actuator to maintain a stable interpole voltage between the electrode and workpiece to realize the high-speed micro-EDM. In this paper, the structure of the magnetic levitation actuator is designed, and the magnetic field characteristics are analyzed. On this basis, an integrator and regulator are used along with a controller with local current feedback to eliminate steady-state errors, stabilize the control system, and improve the bandwidth and positioning accuracy of the magnetic levitation actuator, and the dynamic performance of the actuator is evaluated. The experimental results show that the developed actuator has excellent positioning performance with micron-level positioning accuracy to meet the demand for the real-time, rapid, and accurate adjustment of the interpole gap during micro-EDM.

This paper describes improvement of the ability to recognize sweet peppers for picking robot in greenhouse horticulture. A prototype of the picking robot for sweet peppers has been manufactured. This robot has an image processing system, a camera positioning system, and a cutting device. However the ability to recognize sweet peppers was low, the picking ability was also low. The color of fruits of sweet peppers is almost same color of leaves of it. For identifying a fruit from leaves, this system needs the lighting system. At first we used the fluorescent lamp on the lighting system. In this system, it was possible to identify only fruits in the condition of mixed fruits and leaves. However, if the fruits overlapping with several other fruits, the shapes of these fruits did not exactly recognize, and it is possible to be different the two fruits that are recognized by right and left camera. In this case, because it cannot to exactly measure by stereovision system, the picking ability became low. So we use the new lighting system with LED. In the result of experiments, this CDD lighting system improves the ability to recognize the sweet peppers

Electrical discharge machining (EDM) is not limited to the strength and hardness of conductive materials, and is a non-contact special processing technology. In micro-EDM, there are problems such as untimely axial positioning, unstable inter-electrode machining voltage, and difficulty in discharging inter-electrode electric erosion products. This paper considers a magnetic actuator with fast response and high accuracy as the local actuator for a micro-EDM. By introducing a domain adjustment mechanism, a variable domain fuzzy PID controller was designed to control the inter-electrode voltage control system of the magnetic actuator for micro-EDM using an intelligent control strategy. During the micro-EDM machining process, the controlled magnetic actuator drives the tool electrode in the axial direction for rapid micro-positioning, thus maintaining effective inter-electrode machining voltage and achieving a high-speed and high precision EDM. Simulation and experimental results showed that compared with traditional micro-EDM, the machining efficiency of the variable domain fuzzy PID control magnetic actuator, and traditional micro-EDM cooperative control, was increased by 40%, the machining process was more stable, and the quality of the machined surface was better.