Axis Of Turntable Research Articles

An efficient automated measurement method for aero-engine fan blade geometric parameters

The length of aero-engine fan blades usually exceeds 1 m, making contact-based coordinate measuring machines (CMM) costly and time-consuming. To enhance measurement efficiency and accuracy, we developed a large-field flexible measurement system. We propose the system calibration method using a standard sphere as the reference and taking the turntable axis into account. A model-driven path planning and multi-view data fusion (MVDF) strategy was introduced to enhance efficiency and reduce misalignment due to the robotic arm’s lower positioning accuracy. To improve cross-sectional data sorting and thinning, we proposed an adaptive threshold synchronous sorting and noise suppression method. Additionally, we developed algorithms for chord length and maximum thickness extraction to streamline the process. Experiments show improved accuracy for blade thickness (0.092 mm) and chord length (0.096 mm).

Perpendicularity Detection of Multistage Rotor Considering Compensation of Datum Error

Perpendicularity is an orientation tolerance, and the perpendicularity of end face can be utilized to assess the axial assembly precision of multistage rotor. The aim of this article is to detect the perpendicularity and parallelism of rotor using turntable-rotating approach. The misalignment between datum system of rotor and measurement datum of turntable will introduce the datum error, which is difficult to be thoroughly eliminated by the mechanical device of centering and leveling. To ensure that each measurement is carried out in the same datum system of rotor, the residual error of tilt and eccentricity between two datum systems is studied and compensated. The direction of assessment datum axis of rotor perpendicularity is determined by rotor axis rather than extrinsic measurement datum e.g. turntable axis. The experiment of rotor is performed to verify the effectiveness of the presented detection approach. The difference and relationship between rotor perpendicularity and parallelism are investigated and discussed. It is recommended that parallelism and perpendicularity should be considered together to fully reflect the axial geometric tolerance of rotor. The presented approach is general, which can also be conveniently utilized to detect axial geometric tolerances of other rotating components. For example, compressor rotor, motor rotor, gas turbine rotor, etc.

光学测量系统中相机主点与转台轴线的对中方法

光学测量系统中相机主点与转台轴线的对中方法

Experimental Investigation on Fuzzy PID Control of Dual Axis Turntable Servo System

The paper presents a fuzzy PID control method for a dual axis turntable servo system, which is used to reflect the sun light to the window of the residents. First, the mathematical model of dual axis turntable is established, which is expressed in the state space. Second, a fuzzy PID control method is proposed, and the parameters of PID controller are adjusted online by fuzzy logic to be optimized. Third, the simulation module is built in Matlab to prove the effectiveness of the fuzzy PID method, and it shows that the fuzzy PID method can meet the task requirement. At last, the experiments are performed to verify the rationality and feasibility of the dual axis turntable servo system.

The Research of Algorithm to Obtain High Precision of Angle Sensor

This paper introduces how to use the testing circuit board of measuring accuracy ofthe sensor, testing circuit board is made by the SCA100T - D01 biaxialanglesensor, ATmega8 MCU, ADS8344AD converter, MAX232 and other related components.Through the three axis turntable to rotate a precise angle, which makes thesensor in the testing circuit board has the output value, the output value indata processing, to find out the best coefficient, so as to achieve therequirements of high precision.

A Tool-Free Calibration Method for Turntable-Based 3D Scanning Systems.

Turntable-based 3D scanners are popular but require calibration of the turntable axis. Existing methods for turntable calibration typically make use of specially designed tools, such as a chessboard or criterion sphere, which users must manually install and dismount. In this article, the authors propose an automatic method to calibrate the turntable axis without any calibration tools. Given a scan sequence of the input object, they first recover the initial rotation axis from an automatic registration step. Then they apply an iterative procedure to obtain the optimized turntable axis. This iterative procedure alternates between two steps: refining the initial pose of the input scans and approximating the rotation matrix. The performance of the proposed method was evaluated on a structured light-based scanning system.

Moving Target Detection and Tracking Control Simulation Platform

Moving target detection and tracking simulation platform of two-dimensional translational and three axis turntable are used to target the screen drag and three-dimensional angle attitude simulation of the control problem in essence belongs to the electric servo control. In terms of the design of the servo control, motion control platform including hardware design, the control law design of the control system and software design. Detailed describes the motion platform of mathematical modeling, control circuit and the control law design, through simulation and experiment verify the validity of the motion platform control system.

New Redundant Architectures in Machining: Serial and Parallel Robots

New machine architectures were born during these last years pushed by industrial exigencies in terms of productivity. In this paper, we propose to study the performances that two new machining architecture including hybrid robot with a parallelogram closed loop and a parallel structure can offer. These two robots are combined with a 2 axis turntable in a 8 DoFs robotic cell. Three redundant parameters are used to optimize the path planning. The criteria used to optimize the behavior of each robotic cell and to assess their behavior are presented in this paper along with a comparative study of the kinematic performances and stiffness performances of the two architectures.

Hardware-in-the-Loop Simulation and Flight Experimentation of the Control System on a Small Solid Rocket

By using the Perturbation Theory and solidification coefficient method, based on the interpolation parameters for optimal control feedback matrix, the design of optimal roll control system for a small solid rocket is achieved. The hardware-in-the-loop simulation platform built with DSPACE real-time simulator and high-precision three axis turntable is designed to validate the optimal control law. As for no feedback device of the steering gear, the radios are used to transfer the signals between the devices in the closed loop simulation system. Finally, through the flight-testing, the results confirm a good stability of the roll control system and the high reliability of the hardware-in-the-loop simulation platform.

Design and Test of MEMS Attitude Measurement Unit for Fall Detection

Fall is a risky event in the elderly people’s daily life, it often cause serious injury both in physiology and psychology. A MEMS attitude measurement system is designed for fall detection in real time. This paper presents the design and error test of the attitude measurement unit. Each unit contains orthogonally mounted triads of accelerometers, magnetometers and gyros. With an integrated microcontroller for attitude calculating and flash for data storage, the size of the unit is 32mm×23mm×12mm. An extended Kalman filter based on quaternions is designed for attitude measurement. The digital angle output rate is 100Hz. A new method based on coordinate transformation for attitude measurement error test is introduced, using a single axis turntable and a fixed angle wedge. Theory of the testing method is presented and test experiments are performed. Test results show that attitude measurement error is less than 2°, which meets the requirement of fall detection precision. The fall detection system consists of five attitude measurement units fixed on the human legs and waist.

Application of CAD and Finite Element Method in the Gravity Center Analysis of Body Rotating Cable-Stayed Bridge

Body rotating bridges are mostly rotation system in balance, whose gravity center are basically located in the rotation axis of turntable. In order to ensure bridges’ swivel construction successfully accomplished, the structural center of gravity should be made clear before the rotation. In the past, the structural center of gravity was usually ascertained in the method of mathematics, but the tedious calculation couldn’t get results with enough accuracy. In this paper, structural gravity center of cable-stayed bridge is calculated in the method of CAD and finite element, whose process and result are proved handy and accurate calculation. Taking Sui Fenhe cable-stayed bridge as an example, its theoretical eccentricity is 1.3cm.

Calibration of a multiple axes 3-D laser scanning system consisting of robot, portable laser scanner and turntable

A multiple axes 3-D laser scanning system consisting of a portable 3-D laser scanner, a industrial robot and a turntable is demonstrated. By using a criterion sphere, a robot tool center point (TCP) calibration approach is proposed to calibrate the relation between the laser 3-D scanner and the robot end-effector. In this approach, two different translational motions of robot are first made to determine the rotation part, and then at least three different rotational motions are made to determine the translation part. Meanwhile, by using the criterion sphere, a turntable approach is proposed to calibrate the pose of the turntable relative to the robot. In this approach, several rotational angles of turntable and two different heights of the sphere are made to determine the rotational axis of turntable. Experiment is performed on a portable laser scanner mounted on an industrial robot ABB IRB4400 with a turntable. The experiment results show that the two proposed calibration algorithms are stable and flexible. The application of 3-D measurement is also given to demonstrate the effectiveness and stability of the multiple axes 3-D laser scanning system.

A novel method for adjusting CCD camera in geometrical calibration based on a two-dimensional turntable

In order to ensure the accuracy of the collimator viewing angles in geometrical calibration of the CCD camera, a novel method for adjusting CCD camera with wide field of view based on a two-dimensional turntable was presented. The method involves two steps: the first is to adjust collimator parallel to a rotation axis of turntable by estimating a fixed point image of collimator on the CCD when the camera is orientated around this rotation axis; the second step is to adjust the camera axis parallel collimator by estimating the symmetry of point images when the camera is orientated around another rotation axis of turntable. As an example, the adjustment accuracy of the wide field of view radiometer developed by us is analyzed and discussed in the article.

Horizontal Linear and Angular Responses of Neurons in the Medial Vestibular Nucleus of the Decerebrate Cat

Responses to linear accelerations in the earth-horizontal plane (typically provoked by tilts of the head or body) are characterized by a stimulus direction that produces the maximal excitation. Although changes in cardiovascular, sympathetic, and respiratory outflow are maximized during pitch, no collection of central vestibular neurons had been identified where pitch responses predominate. In the present study, response properties of neurons in the medial vestibular nucleus were examined in decerebrate cats placed on a turntable. Activation of otolith afferents was provided by constant velocity rotation with the turntable axis tilted 5 degrees from the vertical. Responsive neurons exhibited a sinusoidal modulation in their firing rate; the optimal excitatory stimulus direction was derived from responses to clockwise and counterclockwise rotations. Many of these neurons were also tested for input from horizontal semicircular canals using 0.5 Hz sinusoidal rotation about an earth-vertical axis. Of 22 tilt-sensitive neurons in the medial vestibular nucleus whose optimal stimulus direction was determined, 9 were best stimulated by pitch, 10 by stimuli in one of the two vertical semicircular canal planes, and 3 by roll. Of the 33 neurons in this nucleus tested for possible convergent inputs from the otolith organs and the horizontal semicircular canals, 8 responded to both the constant velocity (otolith) stimulus and to the sinusoidal rotation, 7 appeared to receive otolith, but not horizontal canal, input, while 18 had a canal, but no otolith, response. Thus, besides serving as a relay for horizontal canal signals, the medial vestibular nucleus may also be an important relay for information about orientation within the sagittal (pitch) plane.

A patient rotator for stereotactic radiosurgery

A new technique for stereotactic radiosurgery by use of a patient rotator is described. Using the rotator with a small collimated beam of 6 MV X-rays, a small well-defined region of the brain can be irradiated to a high dose with rapid fall off of the dose outside the target volume. Since the linear accelerator gantry does not move during therapy the possibility of a collision between the gantry and the patient or stereotactic equipment is eliminated. The system is also independent of the rotational stability of the linear accelerator gantry axis and turntable axis. Dose distributions measured in a Lucite head phantom with film exhibited properties well suited for radiotherapy. Tests carried out to evaluate the ability to irradiate a selected target point within the brain with the rotator system showed a maximum positional error of 1.0 and 2.0 mm for angiography and CT localisation respectively.