The Research Of The Interior Panel's Laser Weakening System Of Automobiles And The Control Of Remaining Thickness

With the vigorous development of China's automobile industry and people's need of car safety,delicacy and comfort,laser weakening technology will have broad market.Laser weakening technology combines robot automatic control and laser processing technology to ensure the efficiency and precision of laser weakening. This paper reseaches and designes robot automatic control and the remaining thickness control.The electrical control of laser weakening mainly relates to laser control and clamp cylinder control.Through in-depth study of Rofin CO2 laser electrical control,ABB robot fieldbus control and SMC rotary cylinder electrical control, this paper designs control scheme of the laser and the clamp cylinder by ABB robot DeviceNet fieldbus extended I/O ports.In order to control the remaining thickness, it requires a closed loop control system for real-time monitoring.The paper brings up a contol strategy: using a sensor to detect physical quantity that relates with weakening remaining thinkness and according to the output signal's value from the sensor to control the open and close of the laser beam. Closed loop control system mainly consists of two modules: the feedback signal acquisition module and the feedback signal processing module.The feedback signal acquisition module propounds a plan that provides coaxial optical detection on the backside of the workpiece .Comparing the performance and cost of HgCdTe detector,thermocouple and pyroelectric detector, the paper ultimately selects the pyroelectric detector. This module analyzes the pyroelectric detector's response to the pulse radiation theoretically and makes simulaions using Matlab.Comparing capacitance compensation preamplifier,voltage and current preamplifiers it finally selects current preamplifier and makes noise analysis for preamplifier circuit,TINA simulation and actually testing.The test results is consistent with the theoretical analysis and the detection scheme is feasible.The design of the feedback signal processing module mainly relates to pulse signal generator module,duty cycle adjustable module,pulse modulation module and level matching module.Pulse signal generator module is achieved by 555 chip;duty cycle adjustable module is achieved by register and adder; pusle modulation module is achieved using and gate; level match module is achieved using level conversion chip.The final step is to simulate the duty cycle adjustable module and pulse modulation module by Protel DXP.