CN101059694A

CN101059694A - Friction welding machine closed loop control device

Info

Publication number: CN101059694A
Application number: CN 200710017997
Authority: CN
Inventors: 杜随更; 陈强; 傅莉
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2007-06-05
Filing date: 2007-06-05
Publication date: 2007-10-24

Abstract

The invention discloses a friction welding machine closed controller, comprising an electrohydraulic ratio steering speed-adjusting valve, an electrohydraulic ratio overflow valve, A and B power amplifying plates, a D/A module, an A/D module, a pressure sensor and a man-machine interface module, wherein the pressure sensor uses the AD module to convert the analogue signal of cylinder pressure value into digit signal, to be compared with a preset pressure value in a PLC controller and process error calculation, to adjust the overflow pressure of the electrohydraulic ratio overflow valve, to realize the axial pressure control of function cylinder, and the PLC controller receives the direction and speed command transmitted from the man-machine interface module, while the output digit signal via the DA module is converted into analogue signal, to adjust the pressure of the electrohydraulic ratio steering speed-adjusting valve to control the open direction and size of the valve, to realize the motion speed and direction controls of the cylinder piston. The invention uses the PLC controller with analogue amount and man-machine interface function to reduce the valves, accident and realize real-time closed control in welding process.

Description

Friction welding machine closed loop control device

Technical field

The present invention relates to a kind of friction welding machine closed loop control device.

Background technology

With reference to Fig. 2, existing friction welding machine control device comprises slide unit 1, oil pump 4,

fuel tank

5,2/2-way reversal valve 6, surplus valve 7, Programmable Logic Controller (hereinafter to be referred as the PLC controller) 11, oil cylinder 14, pressure switch 16, three position four-way directional control valve 17, two position and four-way reversing valves 18, flow speed control valve 19, retaining valve 20 and reduction valve 21, described PLC controller 11 is the switching mode controller, by six magnet control four direction valves on the PLC controller 11 driving pressure relays 16, and cooperate four pressure and speed control valve to control the friction welding machine axle pressure, slide unit travel direction and speed.In friction welding process, these eight frequent alternating movements of valve, the probability that breaks down is big.In addition, this control device is the process control of PLC controller switches amount, scan round by PLC controller internal processes, read the basis for estimation of such as the switching signal of pushbutton switch, pressure switch, the time relay, travel switch etc. as switch valve output, switch valve and manual governing valve can only make axle pressure be the step evolution variation, can't automatically adjust, can not be to the disturbing factor in the welding process, carry out effectively regulating in real time as the fluctuation of the variation of oil temperature, variation of ambient temperature, welding material and surface state etc.; And parameter such as pressure, flow velocity is regulated inconvenience by manual adjustments, and reappearance is relatively poor.

Document " friction welding process electric-hydraulic proportion computer close-loop control system development [J]. Du Suigeng; Fu Li; Yan Junhui etc. " mechanical engineering journal "; 2002; 38 (12): 135-137 " a kind of use electric-hydraulic proportion commutation flow speed control valve is disclosed and electricity liquid ratio relief valve cooperates industrial control computer to build the pressure closed loop electro-hydraulic proportional control system, this system can control welding pressure accurately, function admirable, pressure controling precision reaches 2%, and be applied to many production scenes maturely, but system complex, manufacturing cost is higher, the software programming difficulty.

Summary of the invention

In order to overcome the many and deficiency that probability is big and can not carry out real-time closed-loop control that causes breaking down of the used valve of prior art, the invention provides a kind of friction welding machine closed loop control device, employing has the PLC controller of analog quantity function and human-machine interface function and electric-hydraulic proportion commutation flow speed control valve and electricity liquid ratio relief valve and controls axle pressure in the friction welding process, can reduce the usage quantity of valve, reduce failure rate.Simultaneously, utilize the PLC controller can also carry out real-time closed-loop control, to keep pressure stable in friction and packing stage.

The technical solution adopted for the present invention to solve the technical problems: a kind of friction welding machine closed loop control device, comprise slide unit, oil pump, fuel tank, the 2/2-way reversal valve, surplus valve, PLC controller and oil cylinder, be characterized in also comprising electric-hydraulic proportion commutation flow speed control valve, electricity liquid ratio relief valve, A power amplification plate, B power amplification plate, the D/A module, the A/D module, pressure transducer and human-computer interface module, described pressure transducer will detect the simulating signal of oil cylinder working-pressure value, become digital signal to give PLC controller by the AD module converts, with the force value of setting by human-computer interface module in the PLC controller relatively and carry out the error computing, the digital signal of output becomes simulating signal through the DA module converts, amplify through A power amplification plate, regulate the oil pressure relief of electricity liquid ratio relief valve, realize the control of application of force oil cylinder axle pressure; Simultaneously, the PLC controller is accepted direction and the speed command that human-computer interface module is transmitted, the digital signal of output becomes simulating signal through the DA module converts, amplify through B power amplification plate, opening direction and size that the electromagnetic force of adjusting electric-hydraulic proportion commutation flow speed control valve is come operation valve realize the movement velocity and the direction control of oil cylinder piston.

The invention has the beneficial effects as follows: owing to adopt PLC controller with analog quantity function and human-machine interface function and electric-hydraulic proportion commutation flow speed control valve and electricity liquid ratio relief valve to control axle pressure in the friction welding process, reduce the usage quantity of valve, reduced failure rate.Simultaneously, the PLC controller can be realized closed-loop control, to the disturbing factor in the welding process, as the fluctuation of the variation of oil temperature, variation of ambient temperature, welding material and surface state etc., can carry out effectively regulating in real time.Parameter such as pressure, flow velocity is easy to adjust, favorable reproducibility.System compares with computer close-loop control, and hardware cost is lower, and programming easily.

Below in conjunction with drawings and Examples the present invention is elaborated.

Description of drawings

Fig. 1 is a friction welding machine closed loop control device synoptic diagram of the present invention.

Fig. 2 is a prior art friction welding machine control device synoptic diagram.

Fig. 3 adopts device welding parameter curve map shown in Figure 1.

Among the figure, 1-slide unit, 2-electric-hydraulic proportion commutation flow speed control valve, 3-electricity liquid ratio relief valve, the 4-oil pump, 5-fuel tank, 6-2/2-way reversal valve, 7-surplus valve, 8-A power amplification plate, 9-B power amplification plate, 10-D/A module, 11-PLC controller, the 12-A/D module, 13-pressure transducer, 14-oil cylinder, 16-pressure switch, the 17-three position four-way directional control valve, 18-two position and four-way reversing valves, 19-flow speed control valve, the 20-retaining valve, 21-reduction valve, 22-human-computer interface module.

Embodiment

With reference to Fig. 1, the force value that drags the oil cylinder 14 of slide unit 1 converts the simulating signal of curtage to by pressure transducer 13, by AD module 12 convert to digital signal deliver in the PLC controller 11 with setting value relatively.Setting value passes to PLC controller 11 by human-computer interface module 22.PLC controller 11 carries out the error computing, to export digital value then and convert the output current that magnitude of voltage removes to control A power amplification plate 8 to by DA module 10, the electromagnetic force of proportion electro-magnet is come the oil pressure relief of control ratio surplus valve 3 on the A power amplification plate 8 output currents adjusting electricity liquid ratio relief valve 3, realizes the pressure control of axial force distribution oil cylinder 14.Simultaneously, PLC controller 11 is accepted direction and the speed command that human-computer interface module 22 is transmitted, the output digital quantity converts the output current that magnitude of voltage removes to control B power amplification plate 9 to by DA module 10, the pressure of proportion electro-magnet comes control ratio direction valve 2 on the B power amplification plate 9 output currents adjusting electric-hydraulic proportion commutation flow speed control valve 2 opening direction and size realize the movement velocity of axial force distribution oil cylinder 14 pistons and the control of direction.Oil pump 4 provides the pressure of hydraulic system.Fuel tank 5 provides system required hydraulic oil.Whether 2/2-way valve 6 control system build pressure.Surplus valve 7 is adjusted hydraulic system pressure.

PLC controller 11 comprises fault detect, cycle time of welding process control, welding pressure linear regulation and control in order to realize the coordination control of whole welding process.Human-computer interface module 22 shows pressure curve and welding parameter is set, the data storage area of PLC controller 11 has stored that slide unit in the welding process moves that needed F.F., worker are advanced, flow and the pressure data of friction, upset, rewind down, PLC controller 11 detects the state of each ingredient in real time in the welding process, provides each stage desired data in real time.By the scan round of PLC controller 11 closed loop programs, real-time control system pressure.Wherein, adopt the pressure closed loop of PID computing to control in friction heating and two stages of upset pressurize.

Slide unit 1 is driving to-and-fro movement by oil cylinder 14.Electric-hydraulic proportion commutation flow speed control valve 2 is by the direction of motion and the speed of oil cylinder 14 control slide units 1.Electricity liquid ratio relief valve 3 control oil cylinders 14 back cavity pressures.Oil pump 4 provides the pressure of hydraulic system.Fuel tank 5 provides system required hydraulic oil.Whether 2/2-way valve 6 control system build pressure.Surplus valve 7 is adjusted hydraulic system pressure.The digital signal that PLC controller 11 provides is converted to current signal through A power amplification plate 8, B power amplification plate 9 respectively through the voltage signal that D/A module 10 is converted to, and controls electricity liquid ratio relief valve 3 and electric-hydraulic proportion commutation flow speed control valve 2 respectively.Pressure transducer 13 detects the back cavity pressure of oil cylinder 14, and the analog signal conversion that A/D module 12 provides pressure transducer 13 is a digital quantity.PLC controller 11 is finished the comparison and control of signal, human-computer interface module 22 shows pressure curves and welding parameter is set, and the data storage area of PLC controller 11 has stored that slide unit in the welding process moves that needed F.F., worker are advanced, the flow and the pressure data of friction, upset, rewind down.This system can realize in the friction welding process closed-loop control of axial pressure, the open loop proportional control of slide unit speed of feed, the axle pressure control accuracy can reach ± and 5%.Parameter regulation is convenient, the reliability height, and system stability is good, and is good to oil sources adaptability, improved the friction welding process controlling level.

Utilize friction welding machine closed loop control device welding Φ 64mm drilling rod of the present invention, adopt C320 type friction welding machine, friction pressure is set at 3.2MPa in the welding variables, and upsetting force is set at 5.0MPa.In system, install speed probe, current sensor, displacement transducer additional, from pressue-graph (referring to Fig. 3), can see, fast in closed-loop control downforce reaction velocity, be straightened condition in friction heating and upset packing stage.From the real data of gathering, in the friction heating period, pressure average 3.2MPa, maximum pressure are 3.27MPa, and minimum pressure is 3.12MPa, and undulating quantity remains in 5%; Upset packing stage pressure average is 5.0MPa, and maximum pressure is 4.79MPa for the 5.24MPa minimum pressure, and the undulating quantity of pressure is not more than 5%, and promptly the pressure controling precision of system is greater than 5%.The welding overlap size uniformity of drilling rod actual production.Monitoring in real time draws to the PLC controller, this closed-loop control system is 16ms in the scan period of friction heating and two stage PLC of upset pressurize controller, be that every 16ms closed-loop control system detects, compares, regulates a pressure, the pressure governing speed is fast, in time systems stabilisation pressure can satisfy the requirement of welding machine pressure control fully.With respect to the closed-loop control system of industrial control computer, the hardware of the closed-loop control system that this PLC controller makes up drops into low, and control accuracy also can meet the demands, but can not show monitoring parameters ruuning situation, program and parameter modification difficulty in real time.With respect to the switch valve control system of routine, the axle pressure control accuracy improves, welding production process parameters favorable reproducibility.

Claims

1, a kind of friction welding machine closed loop control device, comprise slide unit, oil pump, fuel tank, the 2/2-way reversal valve, surplus valve, PLC controller and oil cylinder, it is characterized in that: also comprise electric-hydraulic proportion commutation flow speed control valve, electricity liquid ratio relief valve, A power amplification plate, B power amplification plate, the D/A module, the A/D module, pressure transducer and human-computer interface module, described pressure transducer will detect the simulating signal of oil cylinder working-pressure value, become digital signal to give PLC controller by the AD module converts, with the force value of setting by human-computer interface module in the PLC controller relatively and carry out the error computing, the digital signal of output becomes simulating signal through the DA module converts, amplify through A power amplification plate, regulate the oil pressure relief of electricity liquid ratio relief valve, realize the control of application of force oil cylinder axle pressure; Simultaneously, the PLC controller is accepted direction and the speed command that human-computer interface module is transmitted, the digital signal of output becomes simulating signal through the DA module converts, amplify through B power amplification plate, opening direction and size that the pressure of adjusting electric-hydraulic proportion commutation flow speed control valve comes operation valve realize the movement velocity and the direction control of oil cylinder piston.

2, friction welding machine closed loop control device according to claim 1, it is characterized in that: slide unit motion in the welding process of described PLC controller data storage area stores---F.F., worker advance, friction, upset, the needed flow of rewind down and pressure data, with the real-time detected slide unit motion of PLC controller in the welding process---F.F., worker advance, friction, upset, the needed flow of rewind down and pressure data relatively, by the scan round of PLC controller closed loop program, real-time control system pressure.