Huafang Huang

Study on underwater wet arc welding training with haptic device

Underwater wet arc welding is hard and sometime involves risks to welder divers. To help welder divers gain their underwater wet arc welding skills, a new underwater wet arc welding training method is proposed in this paper based on haptic device. In this method, self-consuming technique is focused on, and fillet welding in different positions is mainly discussed. The haptic device simulates the impacts of seawater acted on an electrode holder, and also guides a trainee to maintain the virtual electrodes proper moving path, proper travel speed, proper compensation speed, proper work angle and the lead angle, and proper arc length. The proposed system is implemented using a Phantom Desktop, and its feasibility is verified. The introduction of a haptic device makes the welder divers training for underwater wet arc welding risk free, convenient and efficient.

Study on one-direction bendable articulated needle

In minimally invasive surgery, steerable needle is needed to perform medical tasks in the deep of a human body. In some cases, a one-direction bendable needle can satisfy actual needs. Therefore, a one-direction bendable articulated needle is proposed in this paper. The proposed needle consists of a beveltip head, articulations, and sections. Articulations can only be bent along the tip direction. Needles structures are analyzed with different head lengths, section lengths, and bending angles of articulations. Basic force analysis is performed to indentify the steering force and the force acting on an articulation. Finally, basic steering analysis is performed to understand a needles trajectory. The proposed needle is more easily to be controlled to avoid obstacles in human body while insertion.

Modeling of one-direction bendable articulated needle

Steerable needles are widely used in minimally invasive surgery. To perform medical tasks well in the deep of a human body, it is required that a needle is easier and more accurate to be controlled and steered. In this paper, the thrusting performances of a one-direction bendable needle are investigated in detail. Such a needle consists of a bevel-tip head, several articulations, and several sections. Articulations are designed that they can only be bent in the direction that is opposite to the bevel-tip, and they are more flexible than the other parts of the needle. The maximum bending angles of articulations are fixed. By changing the lengths of head and sections, and the maximum bending angles of articulations, the possible needle thrusting routes are analyzed. Also, the thrusting forces and moments are calculated based on the structure of the needle. The study results demonstrate that it is easier and more accurate to control and steer a one-direction bendable compared with previous needles. The developments of articulated needle provide the opportunities to design different articulated needle to suit different clinical cases.

Color identification and fuzzy reasoning based monitoring and controlling of fermentation process of branched chain amino acid

The main production method of branched chain amino acid (BCAA) is microbial fermentation. In this paper, to monitor and to control the fermentation process of BCAA, especially its logarithmic phase, parameters such as the color of fermentation broth, culture temperature, pH, revolution, dissolved oxygen, airflow rate, pressure, optical density, and residual glucose, are measured and/or controlled and/or adjusted. The color of fermentation broth is measured using the HIS color model and a BP neural network. The networks input is the histograms of hue H and saturation S, and output is the color description. Fermentation process parameters are adjusted using fuzzy reasoning, which is performed by inference rules. According to the practical situation of BCAA fermentation process, all parameters are divided into four grades, and different fuzzy rules are established.

Study on measurement accuracy of stereo visual sensor based on experimental design

The impact of stereo visual sensor parameters on the measurement accuracy of the sensor is studied based on experimental design. Using a mathematical model of stereo vision, errors caused by stereo visual sensor parameters are analyzed. Based on this, main parameters are identified and used in experimental design. In order to find the optimized combination of the parameters, optimum regression design method is used. Eleven primary experiments with different combinations of parameters are designed and conducted. According to the experiment results, a regressive equation is established. By resolving it, the optimized combination of the parameters is got.