Applied Mechanics and Materials Vols. 190-191

Abstract: For the need of accuracy orientation location about work piece with circle features in vision-based automatic assemble industry, a kind of orientation detection method about work piece based on monocular vision was presented to locate the work piece and then adjust the orientation of assembly parts to guarantee the assembly precision. Ellipse parameters and center point of contours about holes was solved by extracting the center and edge about given the work piece with four holes in the experiment, orientation and location about surface of work piece can be derived. And then Automatic assemble was implemented by orientation of work piece feeding back to robot manipulator to adjust the orientation of assembling part. Experiment analysis has demonstrated that the uncertain of position is less than 8 um and the uncertain of orientation is less than 5 degree.

Abstract: For the path planning for the chassis of duct cleaning robot in an obstacle environment, ant colony algorithm and grid method are adopted to achieve an optimal path between two different arbitrary points and establish the environment model. The results of computer simulation experiments demonstrate the effectiveness of ant colony algorithm applied in path planning for the chassis of duct cleaning robot.

Abstract: A PID controller is designed for an electric clutch actuator, which adopts ball screw as the speed reduction mechanism. Ball screw has high transmission efficiency. However, it does not self-lock. Moreover, the nonlinear friction force, load force, and the nonlinear characteristics of the motor drive circuit increase the difficulty of the position control of the actuator. Model-based control development is used, and the PID coefficients are calibrated based on a simulation model. Then the tuned parameters are used for experimental test. Through experimental results, it is shown that the designed PID controller provides satisfied position tracking performance of the electric clutch actuator.

Abstract: The traditional time series predictive models are not able to achieve a satisfying prediction effect in the problem of a non-linear system and nonstationary time series. To solve these problems, ship course time series prediction, which is based on back propagation wavelet neural network structure and algorithm, was proposed. It combined wavelet analysis and neural network characteristics, and employed the nonlinear Morlet wavelet radices as the activation function. This method was applied to ship rolling motion prediction, and simulation results showed the validity to improving the prediction accuracy.

Abstract: It becomes the urgent and necessary to the development about wide range of manufacturing a multi-functional and human intelligence rescue robots because of difficulty of rescuing the wounded person in a disaster such as earthquakes and other disasters. A rescue robot prototype has been designed, assembled and commissioned based on the rescue mission and rescue needs of the students in Zhejiang Province mechanical design contest. The rescue robot is able to implement going through the tunnel and the bridge, removing the rescue objectives and other actions tasks. The rescue robot has a structure of four-wheel drive, variable center distance which can improve the ability of walking on the bridge and grabbing the rescue target by suction cups to complete the contest tasks. Experiment verified that the design of actuators and control system is reasonable. It took a total of 1 minute 18 seconds to complete the rescue work in Zhejiang Province mechanical design competition.

Abstract: Hybrid-driven mechanism synthesis the constant speed motor and the servo motor as the power source through a multi degree of freedom mechanism. The text study on the trajectory planning of hybrid-driven planar 3-RRR mechanism. Firstly, based on compatible link combinations, all possible basic configurations of planar 3-dof kinematics chains were derived. Based on the requirements of hybrid-driven mode, the kinematics chains were selected one by one Planar 3-RRR mechanism was determined to be the research object finally. Then, based on the conclusions of inverse kinematics analysis, using the cubic spline function on point to point path planning, the servo motor rotation laws were presented. Comparing the different speed situation of constant motor, the influence trends on planning results were analyzed.

Abstract: A novel frequency shift keying (FSK) receiver is presented, including receiving antennas, a low noise amplifier (LNA), band-pass filters (BPF) and a novel all-digital 2-level FSK demodulator. The Matlab simulation results of the all-digital FSK demodulator show that it can improve bit error ratio (BER) performance compared with pseudo-coherent FSK demodulation (PCFSK). The novel FSK demodulator defined using Verilog HDL is easy to be implemented on Field Programmable Gate Array (FPGA) and in CMOS integrated circuit. The whole FSK receiver designed and implemented on a PCB board can receive FSK signal and send the recovered data to computer through RS-232 interface.

Abstract: The thesis describes the feature and system principle of a new type automatic solar tracker in the Solar Radiation Observing System. The new type automatic solar tracker is absolutely automatic、all-weather and with high precision. The system plans two control modes: orbit tracking mode and sensor tracking mode. In the paper the rationale and the project of the two control modes in the system is elaborated and the smooth switch between the two control modes is discussed.

Abstract: Inspired by the research of human visual system in neuroanatomy and psychology, the paper proposes an road traffic sign identification model based on vision bionics.The model combines data-driven and task-driven visual attention mechanism to focus on traffic sign target rapidly and accuractly.Firstly,It simulates the Itti attention model to obtain “what” information and uses the priori knowledge of positional distribution of traffic sign as “where” information.Then,it adjusts saliency map according to “what” and “where” stream so as to select traffic sign focus preferentially.Secondly,it measures the similarity of shape and color features between traffic sign and attention region to get interested region.Finally, it segments traffic sign based on color characteristics and classify shape of traffic sign based on the Support Vector Machine method. The experimental results demonstrate that the feasibility and effectiveness of the proposed model; Furthermore, the average accuracy rate of shape classification on DtBs matrix reaches 98%.

Abstract: Due to demands for stability, accuracy and lower postoperative complication in surgery, robotic surgical assistants may assist surgeons by performing specific subtasks such as suturing and knot-tying to reduce surgeon tedium and duration of some exhausting operations. To improve the surgical knot quality and accelerate healing for patients in surgery, trajectory planning of suture clamping point in knot-tying manipulation using a master-slave robot is discussed based on the surgeon’s manual motion of knot-tying. First, the manual knot-tying process is described, and then according to task sequences, trajectories planning of suture clamping point in looping step based on motion synthesis of rotating joint and swinging joint and pulling step based on slip knot theory are proposed separately to form a knot. To verify the reasonability of trajectory planning, knot-tying motion is simulated by Solidworks. And finally the knot-tying experiment is implemented on the specific robotic setup. The results show that the proposed trajectory planning of knot-tying is feasible in the automation of surgical knot-tying manipulation.