Magnetic tracking method can achieve wireless tracking and has no line-of-sight problem, therefore it is a good choice to track micro devices inside human body for minimally invasive examination or operation. This method is mainly based on the sensing of the magnetic field generated by small permanent magnets. Usually magnetic dipole model is used to estimate the magnetic field. The disadvantage is that only 5 degree-of-freedom (DoF) pose information can be estimated, with the self rotation information missed. In this paper, we proposed an improved 6D pose detection method, which is based on multiple magnets tracking method. Two magnets with opposite magnetic direction have been combined together to serve as the tracking target. Therefore, we can estimate the missing self rotation information according to the relative movement of these two magnets. Experimental results verified the proposed method. The average position error is 3.0mm and the orientation error is 5.1°.

Magnetic tracking method is mainly based on sensing of the magnetic field generated by the magnetic source. Usually a small permanent magnet is used as the magnetic source, and magnetic dipole model is used to estimate the magnetic field. The disadvantage of this approach is that only 5-D pose information can be estimated, but the spin rotation with respect to the direction of magnetic moment cannot be detected. In our previous work, we proposed a novel 6-D (3-D position and 3-D orientation) pose detection method, which was based on an opposing-magnet pair system. The disadvantage is that different rotational parameters may lead to the same pose result due to the symmetric structure of object magnets. In order to solve this problem, we propose an improved 6-D pose detection method in this paper, which is based on a novel constraint multiple magnets tracking algorithm. Two magnets of different sizes with opposite magnetic directions have been combined together to serve as the tracking target. By applying the constraint multi-magnet tracking algorithm, 5-D pose of each magnet can be obtained. Therefore, we can estimate the missing spin rotational information according to the relative movement between these two magnets. Experimental results verified the feasibility of the proposed method. The average position error is 2.3 mm and the orientation error is 4.36°, when the volume ratio between these two magnets is 1:1.5.

Flexible manipulator enables curvilinear accessibility through small incisions or natural orifices for minimally invasive surgery and diagnosis, which makes it a good choice for minimally invasive surgery. In order to control the robot precisely and safely, the real-time position and shape information of the robot need to be measured well. In this paper, we propose a magnetic tracking based tip pose and shape detection method for wire driven flexible robots. A permanent magnet is mounted at the distal end of the robot. Its magnetic field can be sensed with a sensor array. Therefore, position and orientation of the tip can be estimated utilizing the tracking method. A shape sensing algorithm is then carried out to estimate the real-time shape based on the tip pose. With the tip pose and shape display in the reconstructed visual environment, navigation can be achieved. This method provides the advantages that no sensors are needed to mount on the robot and has no line-of-sight problem. Experimental results verified the feasibility of the proposed method. A navigation error of 1.9mm is achieved.

Magnetic tracking technology is emerging to provide an occlusion-free tracking scheme for the estimation of full pose of various instruments. This brings substantial benefits for intra-corporeal applications, such as tracking of flexible robots or wireless endoscopic devices, and thus is helpful for further computer-assisted diagnosis, interventions, and surgeries. Towards efficient magnetic tracking, we propose a magnetic localization and orientation system in this paper. By modeling the cylindrical magnet, the magnetic models have been compared and analyzed. Moreover, we present a sensor layout strategy based on grid method and its optimization method for better performance. Based on the magnetic model and the layout optimization results, we have built a sensor array for magnetic positioning. Extensive simulations and experiments have shown the feasibility of the proposed system with the average positional and orientational errors of 1.4mm and 3.4°, respectively.

Magnetic tracking method can achieve wireless tracking and has no line-of-sight problem; therefore, it is a good choice to track micro devices inside human body for minimally invasive examination or operation. In this letter, we propose a novel six-degree-of-freedom (DoF) pose detection method, which is based on multiple magnets tracking method. Two magnets with opposite magnetic moment directions have been combined together to serve as the tracking target. By defining pose parameters based on the position and orientation constrains of the two magnets, 6-DoF pose information can be estimated with the optimization method. Experimental results verified the proposed method. The average position error is 3.5mm and the orientation error is 1.9°.

Stable control of the ball mill grinding process is very important to reduce energy losses, enhance operation efficiency, and recover valuable minerals. In this work, a controller for the ball mill grinding process is designed using a combination of model predictive control (MPC) with the equivalent-input-disturbance (EID) approach. MPC has been researched and applied widely as one of the multi-variable control algorithms for grinding. It is used to decouple in real time. The controller design does not deal with the disturbances directly. However, strong disturbances such as those caused by ore hardness and feed particle size exist in the ball mill grinding. EID estimates the equivalent disturbance of the grinding circuit in the control input channel and integrates this disturbance directly into the control law in order to suppress disturbances promptly and effectively. This results in good disturbance suppression performance. Simulation results demonstrate that the combination of MPC with EID for controlling the ball mill grinding circuit yields better performance in terms of disturbance rejection, rapid response, and strong robustness as compared to the performance of the MPC and proportional-integral (PI) decoupling control.

Magnetically manipulated untethered robot, such as an active wireless capsule endoscope, has shown great potential for controlled inspection inside the gastrointestinal tract. To enable the effective manipulation of the robot, real-time pose (position and orientation) information of the robot must be obtained as an important sensory feedback. Usually, a magnetic tracking method is used to provide the pose information. Due to the magnetic disturbance, a traditional magnetic tracking method cannot work simultaneously with the magnetic manipulation system. In this paper, a simultaneously tracking and navigation method is proposed to realize a closed-loop control of the magnetically manipulated untethered robot. The main approach is to conduct a multi-object tracking of the involved magnetic objects. With the proposed method, real-time pose information can be estimated during the manipulation, and both the tracking and manipulation are carried out by a magnetic manner. Therefore, the mobile navigation of the magnetically manipulated untethered robot can be achieved by using a pre-defined map. Experimental results verified the proposed method, and a mean position error of 1.2 mm for the passive magnet has been obtained.

This paper is devoted to investigation of Holling type II predator–prey systems with prey refuges and predator restricts. Using a transformation technique, we change the system into a generalized Liénard system and give sufficient conditions to ensure the global stability of the positive equilibrium and existence and uniqueness of a stable limit cycle. We also find the property of alternation for phase structure of the system.

All the leading products and services, such as iPod and Sony Walkman, are the practices of design-led strategy firms. Design is in the center of business value generation and sustainable competitive advantage. The general perception of design is that it is about creating something that looks capability or larruping. Many firms are realizing design's potential to drive their competitive position.The paper introduces a new model of design leadership strategy in firms. First, It describes what is design leadership strategy (design leadership strategy are driven by design and insist that design and design thinking be embedded throughout the firm, and is responsible for moving company out of its business stalemate) and the benefit of the strategy.Second, it analyses how design-led strategy model work, through contrast the design-led strategy model with a classic model. Then, with a example of Ziba, validate the model. It leads to a conclusion that Design leadership strategy is the bridge to attract an almost-fanatical following, gain much-needed free publicity, and even improve the image of brand. Whether that design is incremental or a surprising breakthrough, it contributes heavily to our life.At last, it suggests a number of important practices which should be paid attention to for designers and managers in order to establish the model, design-led strategy.

To satisfy users diversified requirements, the concept of product design DNA was proposed and became a hot research topic in industrial design. In this experimental study an approach of shape perception is proposed to extract the product design DNA; the relation between shape perception and product design DNA is explored. Taken the gas-cooker's shape design as an example, the novel approaches, cluster analysis and semantic differential (SD) method, were employed. Then four design elements (DNA) of designers' shape perception are explored; the weight factors of these elements are obtained; thereby providing a certain methodology direction for the extraction of product design DNA and for the combination between designers' shape perception and product design DNA in the product design.

Image segmentation method based on level set model has wide potential application for its excellent seg-mentation result. However its complex computing restricts its application in video segmentation. In order to improve the speed of image segmentation, this paper presents a new level set initialization method based on Chan-Vese level set model. After a simple iterative, we can separate out the outline of objects. Experiments show that the method is simple and efficient, with good separation effects. The improved Chan-Vese method can be applied in video segmentation.