The Motion Control and Processing Software Design of an On-line Automatic Aluminum Wheel Recognition System

Abstract

This paper presents the motion control and software design of an on-line automatic recognition system for automobile aluminum wheels. The system mainly consists of a recognition station, two laser displacement sensors, a ball-screw, an industrial computer with data processing software, and a programmable logic controller (PLC). The motion control, which incorporates technologies of microelectronic and computer combining the information and intelligence with mechanical devices and power equipments, ensures stability of the wheel recognition system. Each wheel can be identified correctly in less than 20 seconds due to the robust processing software, and the designed action has been achieved accurately. In addition, the man-machine interface is concisely clear and can be easily manipulated and upgraded. The recognition system could meet the requirement of modern wheel manufacturing with a great deal of flexibility. Introduction The growth of economy and enhancement of consumption ability in China has help to popularize automobiles, which brings Chinese automobile industry’s quite rapid development during the past 20 years [1]. It is well known that, the aluminum wheels are one of the most important automobile parts and their extensive use put forward a higher requirement for quality and quantity. The typical production processes of the automobile aluminum wheels are metal melting, purification process, low-pressure casting, X ray radiographic inspection, heat treatment, machining, dynamic balancing detection, leakage test and painting in sequence [2]. After the casting stage, the wheel blanks usually are transferred on a roller bed in random order through a series of process steps. Therefore, each wheel should be identified and classified correctly before each processing step. Fig.1 shows a typical aluminum wheel. Fig.1 The typical configuration of the aluminum wheel Traditionally, the wheel identification is based on operators’ observation and practical experience, which could be unreliable, costly and time consuming. It is becoming harder and harder for traditional recognition method to address market requirements. To improve productivity and reduce cost, the development of an on-line aluminum wheel recognition system is necessary. Wheel spoke Bolt hole Wheel lip Wheel riser Wheel rim 4th International Conference on Computer, Mechatronics, Control and Electronic Engineering (ICCMCEE 2015) © 2015. The authors Published by Atlantis Press 423 This paper aims to propose the motion control and processing software design for the on-line automatic wheel recognition system, which incorporates technologies of microelectronic and computer to combine the information and intelligence with mechanical devices and power equipments. System design for recognition Recognition System Structure. Fig.2 shows the schematic diagram of the automation aluminum wheel recognition system. In this system, a recognition station is used to center, lift and turn the wheel; a roller bed is used to deliver the wheel; two laser displacement sensors are used to scan the wheel; and a ball-screw is used to drive laser displacement sensors with a servo motor. Fig.3 The structure of the wheel recognition system Mechanical Kinematic Scheme Design. During the recognition process, when a wheel is delivered to the recognition station by the roller bed, a signal is sent to PLC to control the recognition station to clamp the wheel. As the wheel being adjusted centering and lifted, PLC generate a signal to the industrial computer, and then the industrial computer control laser displacement sensor 1 driven by a ball-screw to scan the wheel at a uniform velocity of 250mm/s along the centerline of the wheel from point a to point b. As long as laser displacement sensor 1 reaches point b, it stops scanning and initiates a signal to PLC which will stop the movement of laser displacement sensor 1. Then, PLC controls the station to rotate the wheel. Laser displacement sensor 2 then scans the spokes while the wheel is rotated. It is worth noting that the height of laser displacement sensor 2 can be adjusted automatically to meet the measurement of various wheels. When one rotation is finished, the movement of the wheel and laser scanning stops. After the above procedures, the laser displacement sensors and wheel recognition station return to the initial state. The data collected by the two laser displacement sensors are transferred to the industrial computer through universal serial bus (USB) communication. The scanning strategy of the two laser displacement sensors is shown in Fig.3 [3].