CN100422451C - Mechanical digger full power control system and method - Google Patents
Mechanical digger full power control system and method Download PDFInfo
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- CN100422451C CN100422451C CNB2005102001851A CN200510200185A CN100422451C CN 100422451 C CN100422451 C CN 100422451C CN B2005102001851 A CNB2005102001851 A CN B2005102001851A CN 200510200185 A CN200510200185 A CN 200510200185A CN 100422451 C CN100422451 C CN 100422451C
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Abstract
The present invention relates to a full power control system and a method for a digger, which is characterized in that the pressure of a main pump and the pressure of the negative flow quantity of the main pump are detected, the signals which are obtained by detection are transmitted to a feedforward-feedback regulator to be processed, and the signals which are processed by the feedforward-feedback regulator are superimposed with PID regulator signals to drive an electro-hydraulic proportional valve; the feedforward-feedback regulator is used for regulation within certain time delta T (20 to 150 ms) after the negative flow quantity of the main pump starts to lower. A PID regulator is used as a main regulator to regulate the absorption power of an oil pump; the PID regulator has the advantages that the energy is saved, the utilization ratio of the power is improved, the operation efficiency is enhanced, the impact is eliminated, the smoothness of a diesel engine curve is improved, the absorption power of the oil pump can be regulated, and the rotation speed of a diesel engine can be stabilized in a specified value. Thus, the absorption power of the oil pump and the output power of the diesel engine can be fully matched; the work efficiency is improved, and the functions of energy saving and environmental protection can also be realized.
Description
Technical field
The present invention relates to a kind of mechanical digger full power control method.
Background technology
When original excavator design, the mode that power match adopts is the peak power that the peak power that allows oil pump absorb is slightly less than the corresponding throttle position of diesel engine.As long as the driving torque of oil pump is slightly less than the clean output torque of the corresponding throttle position of diesel engine, just can satisfy the fundamental prerequisite of system stability work in other words, shown in Figure 1 as appendix.Because the hyperbola of the approximate constant power that the characteristic curve of constant output pump is the straight line of two Different Slope to be constituted, as shown in Figure 2: when load pressure surpass main pump work play pressure regulation power the time, dcb regulates automatically along characteristic curve.Load variations is indefinite during operate as normal, if diesel engine speed is constant, the power of its output also is constant, but because load variations is indefinite, its power absorbed also changes.The power of diesel engine output much just has been wasted like this.Fig. 3 is exactly the speed curves of diesel engine output under original power match mode: desired stable rotating speed (set-point 2100rpm) when the straight line among the figure is represented excavator work.When load was light, the rotating speed of diesel engine was higher than or near set-point.If load is heavier, this moment, diesel engine fell speed seriously, and was lower than set-point for a long time.In this case, the utilization rate of diesel engine is very low, and the equipment action is obviously slowed down.In order to overcome above-mentioned shortcoming, can regulate the absorbed power of oil pump by adjuster, be operated under the state of permanent power thereby reach the control machine.Manually can't regulate,,, because some parts actions lag behind, under the lighter situation of load, could reach the control requirement reluctantly simultaneously because control accuracy is low if adopt simple process control.So having only the microprocessor of employing is that the control core system just can reach accurate control.Realize the total power coupling of oil pump and diesel engine.
Through overtesting, adopt traditional its effect of PID closed-loop control not reach the ideal control requirement.Its closed-loop control block diagram such as appendix are shown in Figure 4.The diesel engine curve of output as shown in Figure 5 at this moment: from the graph as can be seen, can be stabilized in set-point substantially during diesel engine work.But it is level and smooth not enough.And each control crank impacts when beginning to excavate greatlyyer, and it is more that diesel engine falls speed.
Adopt traditional PID closed-loop control process as follows: the signal of measuring the speed probe that diesel engine carries is as feedback signal, this feedback signal drawn the value of control electric current after by the computing of digital PID control algolithm, thereby drive electro-hydraulic proportional valve.The absorbed power that the hydraulic pressure that electro-hydraulic proportional valve produces is regulated oil pump.Make the absorption maximum power of oil pump be not more than the power output of diesel engine.Realized the power match of diesel engine and oil pump by such closed loop.The absorbed power of oil pump increases when the given electric current of electro-hydraulic proportional valve increases, and the oil pump absorbed power reduces when reducing.
Although after Fig. 4 can find to use the PID closed-loop control obvious effects has been arranged, control accuracy also is not fine.
Summary of the invention
Purpose of the present invention just provide a kind of energy-conservation, improve power utilization, improve operating efficiency, eliminate and impact, improve the flatness of diesel engine output speed curve, the absorbed power that can regulate oil pump, guarantee that diesel engine speed can be stabilized in the error range under the set-point.The absorbed power of realization oil pump and the power output of diesel engine are mated fully; Not only improve operating efficiency but also had the mechanical digger full power control method of energy-conserving and environment-protective.
Solution of the present invention is: design a kind of mechanical digger full power control system, this system:
(1), have the main pump pressure sensor, main pump pressure is detected;
(2), have main pump minus flow pressure sensor, main pump minus flow pressure is detected;
(3), have a feed-forward and feedback regulatory function, by detecting the data that main pump pressure sensor and main pump minus flow sensor are sent, carry out feed-forward and feedback control computing, and with output signal after the computing and PID regulator signal superposition rear drive electro-hydraulic proportional valve.
In above-mentioned control system, adopt following method to control:
(1), main pump pressure and minus flow pressure are detected; Detected data are delivered in the feed-forward and feedback adjuster handle according to approximate FUZZY ALGORITHMS FOR CONTROL; Calculate the size of feed-forward and feedback output signal.
(2), the rotating speed to diesel engine detects; Calculate the size of PID conditioning signal by the digital PID control algolithm.
(3), increase suddenly detecting load, the main pump minus flow begin to have descended after a period of time Δ T be between 20～150ms in, feed-forward and feedback output signal and PID conditioning signal are carried out superposition rear drive electro-hydraulic proportional valve.
Advantage of the present invention be energy-conservation, improve power utilization, strengthen operating efficiency, eliminate and impact, improve the flatness of diesel engine output speed curve, the absorbed power that can regulate oil pump, guarantee that diesel engine speed can be stabilized in the error range under the set-point, the absorbed power of realization oil pump and the power output of diesel engine are mated fully; Not only improve operating efficiency but also had energy-conserving and environment-protective.
Description of drawings
Accompanying drawing 1 is conventional hydraulic oil pump P-Q and input torque curve.
Accompanying drawing 2 is single pump performance curves of traditional permanent power and variable pump hydraulic system.
Accompanying drawing 3 is speed curves of diesel engine under original power match mode.
Accompanying drawing 4 is the system block diagrams that adopt traditional PI D closed-loop control.
The speed curves of diesel engine when accompanying drawing 5 is to use the PID closed-loop control.
Accompanying drawing 6 is characteristic curves of main pump under the control system of accompanying drawing 5.
Accompanying drawing 7 is hydraulic system pressure and diesel engine speed variation diagrams when adopting original power match.
Accompanying drawing 8 is normal state type degrees of membership.
Accompanying drawing 9 is system block diagrams that the present invention adopts feed-forward and feedback PID control.
Accompanying drawing 10 is that the present invention adopts feed-forward and feedback PID when control diesel engine speed curve map.
Accompanying drawing 11 is theory diagrams of control system of the present invention.
The specific embodiment
Among the present invention, include for control system:
(1), have the main pump pressure sensor, main pump pressure is detected;
(2), have main pump minus flow pressure sensor, main pump minus flow pressure is detected;
(3), have the feed-forward and feedback regulatory function, be used to receive the data that main pump pressure sensor and main pump minus flow sensor are sent, carry out feed-forward and feedback control computing, and with output signal after the computing and PID conditioning signal superposition rear drive electro-hydraulic proportional valve.
For said system, minus flow pressure changes the variation early than diesel engine speed during load variations.As shown in Figure 7.As can be seen, before the rotating speed of diesel engine dropped to set-point, minus flow pressure had begun to descend life period difference Δ T.Should time difference Δ T through actual measurement, its scope is between 20～150ms.This time difference has enough been regulated.By Fig. 7 also corresponding relation of main pump pressure and load variations as can be seen.If can control in advance by detecting main pump pressure and minus flow pressure, even load rises, and the PID adjuster plays a major role again after certain degree.
Therefore, the control method of the present invention's employing is:
(1), main pump pressure and minus flow pressure are detected; Detected data are delivered in the feed-forward and feedback adjuster handle: the size that calculates the feed-forward and feedback output signal according to approximate FUZZY ALGORITHMS FOR CONTROL.
(2), the rotating speed to diesel engine detects; Calculate the size of PID conditioning signal by the digital PID control algolithm.
(3), increase suddenly detecting load, the main pump minus flow begin to have descended after a period of time Δ T be between 20～150ms in, feed-forward and feedback output signal and PID conditioning signal are carried out superposition rear drive electro-hydraulic proportional valve.
Setting up a precise math model for this feed-forward and feedback controller has certain difficulty, and therefore the FUZZY ALGORITHMS FOR CONTROL of taking to be similar to is set up model.Utilization is two-dimensional fuzzy controller more widely at present, and the control effect is apparent in view.Two input variable all selects for use controlled variable and given deviation E and the deviation of input to change EC basically.And our input variable has two: main pump pressure and minus flow pressure.In order to use two-dimensional fuzzy controller.Both are created as a two-dimensional fuzzy controller respectively.At last with the signal of both output quantity summation backs as feed-forward and feedback.We claim fuzzy controller 1 for the two-dimensional fuzzy controller that is built up by minus flow pressure; We claim fuzzy controller 2 for another two-dimensional fuzzy controller that is built up by main pump pressure:
Rule for fuzzy controller 1 described two-dimentional FUZZY ALGORITHMS FOR CONTROL is:
(1). the word set of the input and output variable of employing is: negative big, negative little, zero, just little, honest;
(2), when deviation when being honest, and deviation variation rate is for negative, the trend that at this moment has error to increase, it is honest should getting controlled quentity controlled variable; When deviation for just hour, and deviation variation rate is being for just, the trend that at this moment has error to reduce should be got controlled quentity controlled variable for negative big; When deviation for negative, the trend of system existing minimizing deviation itself is not so export.Input variable is deviation and deviation variation rate, and output variable is an electric current.
Fuzzy control rule table 1
| EC is negative big | EC is negative little | EC zero | EC is just little | EC is honest | |
| E is negative big | 0 | 0 | 0 | 0 | 0 |
| E is negative little | 0 | 0 | 0 | 0 | 0 |
| E zero | 0 | 0 | 0 | 0 | 0 |
| E is just little | Honest | Just little | 0 | Just little | Honest 0 |
| E is honest | 0 | Honest | 0 | 0 | 0 |
Rule for fuzzy controller 2 described two-dimentional FUZZY ALGORITHMS FOR CONTROL is:
(1), the word set of the input and output variable that adopts is: { negative big, negative little, zero, just little, honest };
(2), when deviation when being honest, and deviation variation rate is being for just, the trend that at this moment has error to increase should be got controlled quentity controlled variable for just little; When deviation for just hour, and deviation variation rate is for negative, the trend that at this moment has error to reduce should be got controlled quentity controlled variable for negative little; When deviation for negative, the trend of system existing minimizing deviation itself is not so export.Input variable is deviation and deviation variation rate, and output variable is an electric current.
Fuzzy control rule table 2
| EC is negative big | EC is negative little | EC zero | EC is just little | EC is honest | |
| E is negative big | 0 | 0 | 0 | 0 | 0 |
| E is negative little | 0 | 0 | 0 | 0 | 0 |
| E zero | 0 | 0 | 0 | 0 | 0 |
| E is just little | Negative little | Negative little | 0 | 0 | 0 |
| E is honest | 0 | 0 | 0 | Just little | Just little |
Only when load shock is big, enable feed-forward and feedback control in actual use.Be that the growth of load selects when very fast controlled quentity controlled variable to impact to eliminate as early as possible; Other times are controlled to be the master by the PID controller.FUZZY ALGORITHMS FOR CONTROL combines with traditional pid control algorithm like this.Solved the total power coupling of diesel engine and oil pump like this.Be referred to as feed-forward and feedback PID control.Its control block diagram as shown in Figure 9.
Because it is unsatisfactory that effect is controlled in desirable PID differential control in actual use.So adopt actual PID differential control algolithm.Its transfer function is:
Wherein Kp is proportional gain, and Ti is the time of integration, and Td is derivative time, and Kd is the differential gain.
Owing to be the digital PID control algolithm, must eliminate the insensitive interval and the saturated influence of integration of some integrations of integration, above-mentioned algorithm is done suitable adjustment in programming process, eliminate adverse effect.
Use through reality, record the diesel engine speed curve map as shown in Figure 10 when adopting feed-forward and feedback PID control.
As can be seen from Figure 10, by the absorbed power that this control system just can be regulated oil pump, guarantee that diesel engine speed can be stabilized in set-point.The absorbed power of realization oil pump and the power output of diesel engine are mated fully; Not only improve operating efficiency but also had energy-conserving and environment-protective etc.This control system can be used as the upgraded product of some excavators, also can improve excavator complete machine performance or the like.
Claims (6)
1. mechanical digger full power control method is characterized in that:
(1), main pump pressure and minus flow pressure are detected; Detected data are delivered in the feed-forward and feedback adjuster handle according to approximate FUZZY ALGORITHMS FOR CONTROL; Calculate the size of feed-forward and feedback output signal;
(2), the rotating speed to diesel engine detects; Calculate the size of PID conditioning signal by the digital PID control algolithm,
(3), increase suddenly detecting load, the main pump minus flow begin to have descended after a period of time Δ T be between 20～150ms in, feed-forward and feedback output signal and PID conditioning signal are carried out superposition rear drive electro-hydraulic proportional valve.
2. mechanical digger full power control method according to claim 1 is characterized in that described approximate FUZZY ALGORITHMS FOR CONTROL is to adopt two-dimentional FUZZY ALGORITHMS FOR CONTROL.
3. mechanical digger full power control method according to claim 2 is characterized in that described two-dimentional FUZZY ALGORITHMS FOR CONTROL adopts two fuzzy controllers, and one is for the two-dimensional fuzzy controller 1 that is built up by minus flow pressure; For another two-dimensional fuzzy controller 2 that builds up by main pump pressure.
4. mechanical digger full power control method according to claim 3 is characterized in that the algorithmic rule of described two-dimensional fuzzy controller 1 is:
(1), the word set of the input and output variable that adopts is: { negative big, negative little, zero, just little, honest };
(2), when deviation when being honest, and deviation variation rate is for negative, the trend that at this moment has error to increase, it is honest should getting controlled quentity controlled variable; When deviation for just hour, and deviation variation rate is being for just, the trend that at this moment has error to reduce should be got controlled quentity controlled variable for negative big; When deviation for negative, the trend of system existing minimizing deviation itself, so do not export, input variable is deviation and deviation variation rate, output variable is an electric current.
5. mechanical digger full power control method according to claim 3 is characterized in that the algorithmic rule of described two-dimensional fuzzy controller 2 is:
(1), the word set of the input and output variable that adopts is: { negative big, negative little, zero, just little, honest };
(2), when deviation when being honest, and deviation variation rate is being for just, the trend that at this moment has error to increase should be got controlled quentity controlled variable for just little; When deviation for just hour, and deviation variation rate is for negative, the trend that at this moment has error to reduce should be got controlled quentity controlled variable for negative little; When deviation for negative, the trend of system existing minimizing deviation itself, so do not export, input variable is deviation and deviation variation rate, output variable is an electric current.
6. mechanical digger full power control method according to claim 1 is characterized in that described digital PID control algolithm is to adopt actual PID differential control algolithm to calculate.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101624941B (en) * | 2008-11-15 | 2011-09-14 | 徐州师范大学 | Energy-saving control method of engineering machinery and constant-resistance moment energy-saving control system of diesel with pressure sense and discharge capacity direct compensation |
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| CN102251546B (en) * | 2011-06-14 | 2013-04-24 | 三一重机有限公司 | Control method for reducing oil consumption of excavator engine |
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Assignee: Liugong Machinery Co., Ltd. Assignor: Guangxi Liugong Machinery Co., Ltd. Contract record no.: 2010450000025 Denomination of invention: Mechanical digger full power control system and method Granted publication date: 20081001 License type: Exclusive License Open date: 20050810 Record date: 20100628 |
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