Qu Dongsheng

Research of 2-DOF planar parallel high speed/high accuracy robot

Reports a novel high-speed/high-accuracy robot: two permanent, linear, DC servomotors drive a 2-DOF planar parallel mechanism to realize high-speed/high-accuracy planar motion. In the design of the planar parallel mechanism, considering the impacted structure and suppressing residual vibration, we separately adopt simulated annealing algorithm and finite element analysis software ANSYS to optimize mechanisms geometrical dimension and section parameter. Test presents that the planar parallel mechanism being optimized includes high stiffness and the robots settling time is decided by linear motors. At last, in order to reduce influence of nonlinear factors (force ripple, loads disturbance and so on) on the settling time of linear motors set-point control, the paper proposes a novel fuzzy self-tuning PID controller. Experiments show that linear motors settling time has been shortened significantly after the novel fuzzy self-tuning PID controller is applied in the system.

On Target Positioning Parallel Robot Control

Designing and manufacturing a type of precision parallel robot for positioning, and realized 6 DOF spacial precision target positioning in micro meter scale are presented in this paper. Principle of the system is dissertated, and a high integrated and accurate control system for parallel robot is designed. All the control modules are integrated in the computer. Based on the research of the parallel robots positioning control arithmetic, the model of target positioning is deduced. A method based on vision for target positioning closed-loop control is studied. In the method, 6 DOF precision target positioning is realized by the loop adjustment of each DOF of the parallel robot on the condition of the relation between coordinate systems is not known completely. Experiments proved this robot system realized 6 DOF auto closed-loop target positioning.

The research of microscopic vision and force sensing signal feedback hybrid position control on cochlear microelectrode testing system

For cochlear microelectrode array the current way of testing is manual operation and it exist technical problems such as difficult to precision positioning, easy to damage electrode surface. The microelectrode automated testing system is developed with the visual image deflection and force feedback hybrid position control. The experimental results show that the use of image information to achieve the positioning error within 20 µm; using force feedback for the position fine-tuning of the probe detecting, keep testing force in 80–150 mN and the error is within 10 mN. Meet the requirement of testing for precise positioning and flexible contact.

Design and Experiment of The Wafer Pre-alignment System

The wafer pre-alignment system is a fundamental part of the lithography. A system for automated pre-alignment of wafer with a diameter of 8 inches is developed. The system consists of three functional units that can achieve the pre-alignment task with high efficiency and high precision, including positioning unit, transporting manipulator and transferring unit. The requirement of positioning and transportation accuracy (less than 7 mum) is essential to design and development of integrated system due to the high precision of IC manufacturing. In this paper, a liner CCD camera with a resolution of 0.1 mum is used to detect the wafer edge and the notch. Major methodology issues, including least square circle fitting approach for calculating the center and radius of the wafer, an edge flexion method for detecting the range of wafer notch, of alignment strategies are introduced. The experimental results show that the accuracy of the wafer notch detection is 3.49 mum and the overall accuracy of wafer positioning is 6.11 mum.

Development of Precision Parallel Robot in ICF Research

In the research of ICF accurate orientation of the sensor is one key factor to guarantee target exactly. So one 6-DOF parallel robot is developed, in which Hooke articulated structure is adopted to suit the heavy-load and requirement of orientation precision. For further enhancing the orientation and repetition precision of the robot, speed of the integrated linear motor is programmed in reason with closed-loop controlling strategy. In the mean while, inverse kinematics model of the parallel robot is set up and network communication based on sever and client is developed to realize remote control of the robot. The results of experiment show that the repeated orientation-precision of the robot proposed is of 1 mum, which can fulfill the accurate adjustment on the pose of robot.

Research of iterative learning control for a novel 2-DOF planar parallel robot

This paper proposes a novel 2-DOF high-speed/high-accuracy robotic system: two permanent linear motors drive a planar parallel mechanism. Analysis of mechanism dynamical model verifies that load variation is violent. Due to the direct-drive principle of a linear motor, the load disturbance can have a significant effect on motor performance. For this purpose, designs a zero phase error iterative learning feedforward controller and feedback controller. At last, experiment results validate that using a causal zero phase error approach, high-performance motion system is obtained. The maximum acceleration is 8 m/s/sup 2/, the maximum speed is 0.5 m/s and the zero phase ILC design has converged after 5 steps to an average error 0.004 mm.