Xiufen Ye

Motion-control analysis of ICPF-actuated underwater biomimetic microrobots

This paper introduces the development of biomimetic underwater microrobots consisting of AVR microcontroller, an infrared ray communication system, and ionic conducting polymer film (ICPF) actuators. We use AVR ATmega16 as the control unit and an infrared ray receiver to provide feedback to the AVR unit. The spiral particle pathway searching approach is developed to search for particles. We also use MATLAB and OpenGL to simulate the path planning and optimisation according to the particle swarm optimisation algorithm. We implemented and demonstrated wireless control over the trajectory of individual microrobot, and extended this to three units in an expect formation.

A survey of off-line signature verification

This paper presents a survey of off-line siwature verification. Off-line signature verification systems are widely used in many areas. The off-line signature features are classified. Many approaches of verification have been investigated. We will discuss these approaches respectively in details and make a comparison. Finally, we will propose some problems existed in the off-line signature verification system. A conclusion of all ithese works and an outlook into the future work will also be presented.

Highly Precise Catheter Driving Mechanism for Intravascular Neurosurgery

Recently, MIS (minimum invasive surgery) has attracted most of doctors and patient. It has been widely used in many kinds of surgeries, especially in intravascular neurosurgery. But there are several problems in intravascular neurosurgery: doctors exposure to X-ray, few well skilled doctors, high risk of the catheter insertion. To solve these problems, we developed a highly precise remote control system by using a master-slave system. In this paper, we expatiate on the design concept of the system and then test the precision of the system. The experiment results basically achieve our design purpose

Design and realization of a remote control centimeter-scale robotic fish

A centimeter-scale robotic fish is proposed and realized in this paper. The robotic fish mimics a type of small crucian. Its swimming pattern of cruise-straight, cruise-in-turning, burst and coast are realized respectively. The remote control function is realized at the base of an infrared sensor. An IPMC actuator and two pieces of PVC film construct a caudal fin to mimic the swing of the small crucian in structure. The whole size of the robotic fish is 98 mm times 45 mm times 20 mm. The length of rigid part of the robotic fish is 2/3 of the whole length. So the payload of the robotic fish is ensured. The optimal size of the IPMC actuator is got through theoretical analysis and experimental validation. To improve the efficiency of experiments, we use modular design in the robotic fish. Every part of the robotic fish can be disassembled.

The computational design of a water jet propulsion spherical underwater vehicle

Underwater vehicles have become an important tool to develop oceans. The design of the shape, hardware circuit and software of a water jet propulsion spherical underwater vehicle was introduced, and the characteristics of water jet pump were presented. The design of the thruster and computation of the thrust was proposed, too. A desired movement result was achieved by the designed spherical underwater vehicle in static water experiments. The experiments proved that the design was feasible, and the spherical underwater vehicle could be regarded as a carrier for further research on correlative control algorithm.

A centimeter-scale autonomous robotic fish actuated by IPMC actuator

This paper presents the research toward centimetre-scale autonomous robotic fish mimicking a kind of goldfish. The robotic fish is propelled by an iconic polymer-metal composite (IPMC) actuator and equipped with a microcontroller and an infrared sensor for wireless control, autonomous navigation and obstacle avoidance. To improve turning ability of the robotic fish, we set the length of caudal fin and the flexible part to half of the whole length. The overall size of the robotic fish is 98 mm in length, 30 mm in width, and 22 mm in thickness. The weight of the robotic fish is 21.9g. The obstacle avoidance method, remote control and turning mechanism of the robotic fish are described respectively in this paper. The experimental results show that the structure of the robotic fish and its avoidance function, remote control and turning method are feasible. In centimetre-scale autonomous robotic fish driven by IPMC actuator, the obstacle avoidance function makes our robotic fish smarter. With the help of this robotic fish we can do some low speed and high maneuver tasks in limited space easily.

A New Jellyfish Type of Underwater Microrobot

In the medical field and industry application, fishlike microrobot and micro biped robot with multi DOF that can swim smoothly in water or aqueous medium has urgently been demanded. And IPMC (ionic polymer metal composite) can generate large bending motions under a low driving voltage (about 1 V), and it has a good response and soft characteristic. In this paper, we have developed a new jellyfish type of microrobot which can imitate the jellyfish. It has a movement process as the jellyfish does when it is floating and sinking. The process of floating and sinking can be controlled. Four legs using IPMC actuators are designed to replace the antennae of the jellyfish. Characteristic of the underwater microrobot is measured. Some improvement has been done for higher efficiency. The experimental results indicate that the moving and swimming speed of underwater microrobot can be controlled by changing the frequency of input voltage.

Grid Search Optimized SVM Method for Dish-like Underwater Robot Attitude Prediction

The control of dish-like underwater robot motion is complex. It involves many kinds of influencing factors and its also a nonlinear process. The model of attitude motion control is very important for the accuracy control and self adapting predictive control. For establishing the attitude motion model and predicting the attitude, SVM algorithm was used to construct a MIMO identifier in this paper. Moreover, in order to improve the effect of the identification and prediction, the grid search method was adopted to optimize the key parameter C and g in SVM. At last the effects were contrasted with GA and PSO optimized SVM algorithm by the data from the experiments in the pool, the results proved the superiority of grid search method in both calculating time and optimizing results. The results show the well performance of this GS-SVM on the identification and prediction for the attitude of dish-like underwater robot.

A simplified dynamics modeling of a spherical underwater vehicle

This paper proposes a spherical underwater vehicle which is propelled by water-jetted motors. It has many characteristics such as small size, light weight, flexibility of motion and noiselessness. In this paper, the dynamics model of the vehicle is analysed according to its design; and the vehicles dynamics model is developed. The dynamics model of propellers for the vehicle is also analysed for modeling. For the sake of simplification, only two hydrodynamic damping forces are taken into account when dealing with this spherical underwater vehicle. Dynamics modeling is simplified according to the architecture and kinematic characteristics of this spherical underwater vehicle.

A novel segmentation algorithm for side-scan sonar imagery with multi-object

Automatic detection of underwater objects using side-scan sonar imagery is complicated by the variability of objects, noises, and background signatures. In recent years, as the resolution of side-scan sonar is much higher than before, the sonar imagery can be generated from sonar signal for processing. The first step of underwater object detection is to segment the underwater objects from sonar imagery. In typical sonar imagery, the object contains two parts: high-light areas (echo) and the shadow behind the object. By analyzing the features of the side- scan sonar imagery, we propose a novel segmentation algorithm for multi-object side-scan sonar imagery. First we utilize a self- adaptive window to scan the imagery and calculate the variance of the window to segment the high-light areas in sonar imagery. Then the shadows of the objects are segmented by fractal dimension. At last, the final segmentation results are achieved by combining the results from the above two steps for further analysis. This segmentation algorithm is based on analyzing the structure of objects in sonar imagery and works well in the multi- object sonar imagery.