An innovative subdivision-ICP registration method for tool-path correction applied to deformed aircraft parts machining

A new and fast registration algorithm has been proposed to update the tool-path of a deburring robot, intended to machining composite workpieces under gravity and clamping deformations. A Subdivision Iterative Closest Point algorithm, which considers different parts of the contour with respect to curvature, allows to obtain far better results than classical methods, without complicated assumptions or computations. The procedure has shown to be effective for porthole and nose-cone deburring. Experimental tests conducted on robotic milling workcell demonstrated the efficiency of the registration method

A hybrid-type active vibration isolation system using neural networks

Vibration isolation of mechanical systems is achieved through either passive or active vibration control systems. Although a passive vibration isolation system offers simple and reliable means to protect mechanical systems from a vibration environment, it has inherent performance limitations, that is, its controllable frequency range is limited and the shape of its transmissibility does not change. Recently, in some applications, such as active suspensions or precise vibration systems, active vibration isolation systems have been employed to overcome the limitations of the passive systems. In this paper, a hybrid-type active vibration isolation system that uses electromagnetic and pneumatic force is developed, and a new control algorithm adopting neural networks is proposed. The characteristics of the hybrid system proposed in the paper were investigated via computer simulation and experiments. It was shown that the transmissibility of the vibration isolation system could be kept below 0.63 over the entire frequency range, including the resonance frequency.close101

INTEGRATED PRECISION INSPECTION SYSTEM FOR MANUFACTURING OF MOLDS HAVING CAD DEFINED FEATURES

An integrated precision inspection system has been developed for manufacturing moulds having CAD defined features. The techniques of precision measurement are implemented for CAD/CAI integration for moulds having sculptured surfaces with some basic features, such as, holes, slots and bosses. Features to be inspected are chosen in the CAD environment, and inspection planning is performed for each feature. The sampling-point strategies are: uniform distribution, curvature dependent distribution, or hybrid distribution of the two depending on the complexity of the sculptured surface. Line and plane features are divided into subintervals, and the measurement points are distributed at random positions in the subinterval. Prime number subintervals are considered for a circle feature, in order to avoid possible periodic distortion of the measurement features. The measurement path planning is performed considering collision avoidance and coordinate matching between the coordinates. The output of the planning is the machine code for a specific CMM having CNC capability. The machine code is downloaded to a specific CMM, and the measurement results are fed back to the computer. A new algorithm, called MINIMAXSURF, is developed to evaluate the form error precisely for sculptured surfaces. The algorithm considers the radius of the touch probe and evaluates the profile tolerance successfully by removing the unavoidable setup errors. The developed measurement system has been applied to real moulds, demonstrating high performance and accuracy.close142

Analysis of the accuracy of the CAD model reconstruction of spiral bevel gears by CMM's digitisation

Springer-Verla