CN104485860B - The control method of electric tool and the electric tool for performing the control method - Google Patents
The control method of electric tool and the electric tool for performing the control method Download PDFInfo
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- CN104485860B CN104485860B CN201410624039.0A CN201410624039A CN104485860B CN 104485860 B CN104485860 B CN 104485860B CN 201410624039 A CN201410624039 A CN 201410624039A CN 104485860 B CN104485860 B CN 104485860B
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Abstract
The present invention relates to a kind of control method of electric tool, wherein electric tool includes output shaft, and the control method comprises the following steps：Measure the parameter for being used for representing to export axle load changed over time；Obtain the first derivative of the parameters versus time；Obtain the second dervative or higher derivative of the parameters versus time；According to the first derivative and the product or the first derivative of second dervative and the corresponding control signal of product generation of higher derivative；And change the output of the output shaft according to the control signal.The invention further relates to a kind of electric tool for performing the control method.Whether the electric tool and its control method that the present invention is provided can reach precalculated position with the work package of automatic detection work head driving, and perform corresponding actions detecting after the work package reaches precalculated position, it is ensured that it will not further cross the precalculated position.
Description
Technical field
The present invention relates to a kind of control method of electric tool, more particularly to a kind of output for being used to control electric screw driver
The method of the output of axle.
The invention further relates to a kind of electric tool for performing above-mentioned control method, more particularly to a kind of execution control method
Electric screw driver.
Background technology
Existing electric tool, such as electric screw driver, electric current is provided by the power supply of loading, carrys out motor rotation, from
And the rotation of work head is crept into screw in plank.Different types of screw has different main diameters, or with not
Same head shape, in this way, its situation crept into same plank is also different.In addition, different planks due to material not
With make it that its hardness is also different, in this way, the situation in the plank of same screw drilling unlike material is also not quite similar.Generally in electricity
During the use of dynamic screwdriver, user needs screw being drilled into the surface that workpiece is pressed close on head, in this way, user's needs are non-
Drilling process is carefully often paid close attention to, controlled motor is stalled when pressing close to the surface of workpiece with the head when screw.So as on the one hand keep away
Screwless head is pierced inside plank too far, on the other hand avoids screw head from being crept into by imprudence after plank, due to meeting with
Made motor overload by excessive resistance.
Usual this electric tool can be provided with overload protection arrangement.This overload protection arrangement can be it is a kind of mechanical from
Clutch, in the case of above-mentioned current overload, can be such that the work head of electric tool departs from motor and coordinate.Protected using this overload
The electric tool of protection unit would generally simultaneously in the front portion of its casing provided with torque cover, i.e., one indicate some scales can
The cover of rotation.These scales represent the limit torsion gear of electric tool work.User can be beforehand through rotation when using
Torque cover sets the limit torque value of electric tool work, that is to say, that when the torsional moment that exports reaches in electric tool work
Arrive or during more than the threshold values set in advance, clutch system can automatically begin to work and make the work head and motor of electric tool
Depart from and coordinate.In addition, can also extend one in the front end of its casing using the electric screw driver of this overload protection arrangement
Remain basically stable the front end of individual sleeve pipe, the front end of the sleeve pipe and the work head of electric screw driver.By this set, when screw is got into
Its head when being attached to the surface of plank, the leading section of sleeve pipe is also attached to the surface of plank, further bores dynamic screw, sleeve pipe meeting
Compressed by plank and it is touched the clutch mechanism in casing, coordinated so that work head and motor depart from.But on
State mechanical clutch structure all complex, make trouble, cost is higher.
The content of the invention
The present invention provides a kind of control method of electric tool, and it can be automatically ensured that by the work head driving of electric tool
Work package reaches precalculated position, and the work package will not further cross the precalculated position.
To achieve the above object, the technical scheme that provides of the present invention is：A kind of control method of electric tool, wherein electronic
Instrument includes motor and the output shaft by motor rotation driving, and the output shaft is used to export rotation torque to drive work head to exist
Worked on workpiece, the control method comprises the following steps：Measure the parameter for being used for representing to export axle load changed over time；
Obtain the first derivative of the parameters versus time；Obtain the second dervative or higher derivative of the parameters versus time；According to described
First derivative and the product or the first derivative of second dervative and the corresponding control signal of product generation of higher derivative；And
Change the output of the output shaft according to the control signal.
To achieve the above object, the technical scheme that also provides of the present invention is：A kind of control method of electric tool, wherein electricity
Power driven tools include motor and the output shaft by motor rotation driving, and the output shaft is used to export rotation torque to drive work head
Worked on workpiece, the control method comprises the following steps：Measure the ginseng for being used for representing to export axle load changed over time
Number；Obtain the first derivative of the parameters versus time；Obtain the second dervative or higher derivative of the parameters versus time；According to institute
State first derivative and the product or the first derivative of second dervative and the corresponding control signal of product generation of higher derivative；With
And the output of the output shaft is adjusted according to the control signal.
The present invention also provides a kind of electric tool for performing above-mentioned control method, and it has Electronic Control Unit, can avoid
The work package driven by work head further crosses the position after precalculated position is reached.
To achieve the above object, the technical scheme that provides of the present invention is：A kind of electric tool, the electric tool includes：
Output shaft, for driving work head, so that work head has rotary speed；Motor, output shaft described in rotation driving；Power supply, is used
In the supply motor electric power；Sensor, the parameter of output shaft load is represented for measuring；Control assembly, it is described for obtaining
The first derivative of parameters versus time；Obtain the second dervative or higher derivative of the parameters versus time；According to the first derivative
With the corresponding control signal of product generation of the product or the first derivative of second dervative with higher derivative；According to the control
Signal changes the output of the output shaft.
To achieve the above object, the technical scheme that also provides of the present invention is：A kind of electric tool, the electric tool includes：
Output shaft, for driving work head, so that work head has rotary speed；Motor, output shaft described in rotation driving；Power supply, is used
In the supply motor electric power；Sensor, the parameter of output shaft load is represented for measuring；Control assembly, it is described for obtaining
The first derivative of parameters versus time；Obtain the second dervative or higher derivative of the parameters versus time；According to the first derivative
With the corresponding control signal of product generation of the product or the first derivative of second dervative with higher derivative；According to the control
Signal adjusts the output of the output shaft.
Compared with prior art, the present invention in electric tool by setting up the Electronic Control Unit of correlation come automatic detection
Whether the work package of work head driving has reached precalculated position, and performs phase detecting after the work package reaches precalculated position
It should act, it is ensured that it will not further cross the precalculated position.Also, due to without using complicated mechanical clutch knot
Structure, makes to be simple to manufacture, cost reduction.
Brief description of the drawings
The invention will be further described with embodiment below in conjunction with the accompanying drawings.
Electric current and the graph of relation of time when Fig. 1 is existing electric screw driver work.
Fig. 2 is the derivative curve figure after derivation of Current versus time in Fig. 1.
Fig. 3 is the derivative curve figure after the secondary derivation of Current versus time in Fig. 1.
Fig. 4 is operation principle block diagram of the electric tool based on the first inventive principle of the present invention.
Fig. 5 is power screw to the electric current and the graph of relation of time during work, and which show two kinds of differences of correspondence
Operative scenario when two different electric current i1, i2 curve.
Fig. 6 be in Fig. 5 difference electric current i1, i2 to the derivative curve figure after derivation of time.
Fig. 7 is according to songs of difference electric current i1, the i2 to control signal s1, s2 obtained from the first derivative of time in Fig. 6
Line chart.
Fig. 8 is operation principle block diagram of the electric tool based on the second inventive principle of the present invention.
Fig. 9 is similar to Fig. 3, is the operating current of electric screw driver to the derivative curve figure after time secondary derivation.
Figure 10 is the derivative curve figure after three derivations of Current versus time in Fig. 9.
Figure 11 is operation principle block diagram of the electric tool based on the 3rd inventive principle of the present invention.
Figure 12 is the schematic cross-sectional view of another embodiment of electric tool of the present invention.
Figure 13 is partial enlarged drawing in Figure 12.
Figure 14 is the schematic perspective view of blanking disc in Figure 13.
Figure 15 is the schematic perspective view of another embodiment of blanking disc in Figure 13.
Embodiment
The control method of the present invention can be applied to polytype electric tool, and main below is specific using electric screw driver
Embodiment is illustrated.
Electric current versus time curve figure when electric screw driver as shown in Figure 1 works.Coordinate shown in reference picture 4, should
Electric screw driver 2 is depressed by a user to drive work package 14, and the work package is screw in the present embodiment, pierces a plank
In 16.The pressing force of user is substantially near a constant.Wherein letter t represents that screw pierces the time of plank and spiral shell therewith
Nail corresponding position in plank.Alphabetical i is represented to be supplied to the electric current of the motor of electric screw driver and is accordingly carried in therewith
Load or driving force on motor.
Curve in Fig. 1 includes Part I A, Part II K, and Part III B.Wherein Part I A is on one section
Curve is risen, it represents that the main part of screw pierces the drilling process of plank, and this section of ascending curve is substantially linear, or
Can be with somewhat curved and setback.The Part II K for following hard on Part I A may also be referred to as inflection portions (knee) K.Should
Inflection portions K is a positive curvilinear motion, that is to say, that inflection portions K has acclivitous prominent relative to Part I A
Become, this represents that the head of screw comes into contact with the surface of plank.That follow inflection portions K closely is Part III B, and it is equally one
Section is substantially linear, or can be with somewhat curved and setback ascending curves.But curve B is more precipitous than curve A to be obtained
It is many.
In fact, what the curve in Fig. 1 represented is the electric tool protected of control method not no using the present invention
Working condition, so the Part III B of curve represents that now electric tool can produce very high electric current and cause screw
Head pierce in plank.Therefore, it is necessary to take necessary measure after inflection portions K to avoid the too high electricity of above-mentioned generation
The situation of stream occurs.
When screw is drilled into position corresponding with inflection portions K, continuing to pierce process not only can pierce the head of screw
In plank, and it may also can damage motor.So, the present invention be based on automatic detection inflection portions K, then detect with
Take corresponding precautionary measures automatically afterwards.
Fig. 2 and Fig. 3 will explain in present embodiment how to detect inflection portions K.
Fig. 2 is that electric current i seeks time t the curve map after first derivative di/dt in Fig. 1.Wherein, the Part I A in Fig. 1
With Part II B on the figure the corresponding straight line being shown as parallel to horizontal axis t, and to be then shown as one anxious by Part II K
The curve that speed rises.
Fig. 2 is that electric current i seeks second dervative d to time t in Fig. 12i/dt2Curve map afterwards.Wherein, the Part I in Fig. 1
A and Part II the B numerical value after secondary derivation have turned into zero, and Part II K is then shown as the parabola that Open Side Down, and
A peak signal p is formed in parabolical top area (including a specific interval including parabola summit).Coordinate reference
Shown in Fig. 4, when peak signal p is formed, a control signal s can be produced therewith.Certainly, in a preferred embodiment,
Can preset a threshold values v, control signal s only when peak signal p be on the occasion of and when being numerically more than default threshold values v
Produce.It can be readily occurred in for one of ordinary skill in the art, control signal s also can be in electric current i to time t first
Produced after secondary derivation, such as by way of capacitor, control is produced after first derivative is detected more than a predetermined threshold values
Signal s processed.
Shown in Fig. 4 is the electric tool of the above-mentioned control method of application of the present invention, below still by taking electric screw driver as an example
Illustrate.Electric screw driver 2 includes work package 4, power supply 18 and switch 20.Wherein work package 4 includes motor 6, is used for
First 8 rotation of the work of driving one, a screw 14 is crept into plank 16.Motor 6 is mechanical to passing sequentially through one between work first 14
Formula spring is connected with the chuck 10 of clutch system 12 and one.Certainly in the present embodiment, clutch system can also be saved.
In present embodiment, power supply 18 is dc source, or rechargeable battery, and the direct current of motor 6 is supplied when can be closed switching 20
Electricity.Certainly, one of ordinary skill in the art can also be readily occurred in, and the direct current in present embodiment is substituted using AC power
Source.
Electronic-controlled installation 22 and the sensor 24 for detecting electric current are connected between power supply 18 and motor 6.This is electronic
Screwdriver also includes one first derivation unit 26 and the second derivation unit 28.In present embodiment, sensor 24 can be detected in real time
The electric current i of motor is supplied, while the generation signal proportional with the electric current that detects and passing to the first derivation unit 26；
Then the first derivation unit 26 tries to achieve first derivative di/dt as shown in Figure 2 according to electric current and time, while generation one is with being somebody's turn to do
The proportional signal of first derivative simultaneously further passes to the second derivation unit 28；Then, the second derivation unit 28 is tried to achieve
Second dervative as shown in Figure 3, and when preparatory condition is produced, it is as noted above when peak signal p be on the occasion of and numerical value
When being above more than default threshold values v, control signal s is generated.In the present embodiment, control signal s be used to reduce motor
Rotating speed is interrupted to motor offer electric power.That is, control signal s be used to the electric current i for supplying motor being reduced to one
Relatively low level reduces to zero, so as to reduce the rotating speed of motor or stall motor.Certainly, control signal s also can by with
In the flow direction for changing electric current i, so that motor 6 can rapidly stop.In the present embodiment, control signal s can be passed
To electronic-controlled installation 22, corresponding action is then performed by electronic-controlled installation 22, these actions can be in peak value letter
Number p is produced or produced after delay a period of time immediately after producing, and the delay can be real in electronic-controlled installation 22
It is existing, it can also be realized by the delay cell being separately provided.
Electronic control circuit in Fig. 4 can include a transistor switch, for disconnecting the electric current of supply motor.
In a preferred embodiment, electronic-controlled installation 22 can include a microprocessor, above-mentioned first derivation unit
26th, the function that the second derivation unit 28 or delay cell that may be present etc. are realized can be by being solidificated in microprocessor
Instruction in device is performed.That is, whole electronic-controlled installation 22 can be a microprocessor.
In other optional embodiments, the electric current i of supply motor 6 can be measured in continuous time interval Δ t,
These continuous time interval Δ t can be identical.The electric current i detected asks two companies respectively then by digitized processing
The first derivative di/dt of Current versus time in continuous time interval, then compares the two first derivatives；If the knot compared
Fruit shows that both are not substantially identical (equivalent to the secondary derivation in aforementioned embodiments), that is, means that the head of screw has been arrived
Up to the surface of plank 16, above-mentioned control signal s can be generated with that.
Above-mentioned embodiment is driven by setting up the Electronic Control Unit of correlation in electric tool come automatic detection work head
Whether dynamic work package has reached precalculated position, and performs corresponding actions detecting after the work package reaches precalculated position,
Ensure that it will not further cross the precalculated position.
Shown in Fig. 5-8 be the present invention control method and electric tool the second inventive principle, below can be to based on this
Each embodiment of inventive principle is elaborated.
Shown in Fig. 5 is the electric current i of motor with time t change curve.In the present embodiment, the electric current of the motor
I is the direct current that an electric screw driver supplies motor when driving a work head job.Two electricity detected are shown in figure
Flow curve A1 and A2.Identical with what it is above, the electric current of detection and processing motor is carried out by clock pulses principle, this category
In technology well-known to those skilled in the art, applicant repeats no more.Shown in Fig. 6 is current curve A1 and A2 through once asking
Corresponding first derivative curve after leading.First curve A1 and the workpiece of relatively soft material, such as plank, or relatively small screw
It is relevant；And the second curve A2 and the workpiece of relatively hard softwood matter, or relatively large screw are relevant.No matter which kind of situation, to song
Line A1 and A2 detection and processing can all be carried out in control assembly 22 (Fig. 8 shows), and in the present embodiment, the control assembly is also
A microprocessor can be included.
In the first embodiment based on the second inventive principle, in a time point T1 set in advance, current of electric i1
It is collected.In the microprocessor, the threshold values of one, referred to as the first threshold values P1 are previously stored with.First threshold values P1 is probably,
For example, at T1 time points, P1=5A (ampere).If now i1<5A, it is meant that current electric screw driver is just softer at one piece
Screw is played on plank；If now i1>5A, it is meant that current electric screw driver just plays screw on one piece of harder plank.Match somebody with somebody
Close shown in reference picture 6, if i1<5A, microprocessor will assign one first default first derivative values q1；If i1<5A, it is micro-
Processor will assign one second default first derivative values q2.Above-mentioned first and second default first derivative values q1, q2 all by
Prestore in the microprocessor.First default first derivative values q1 can be, for example, q1=0.4A/s；Second default single order
Derivative value q2 is more than the first default first derivative values q1, Ke Yishi, for example, q2=1A/s.If that is, in time point T1
When motor current value i1 less than the first threshold values P1, the first default first derivative values q1 can be chosen, whereas if in time point T1
When motor current value i1 be higher than the first threshold values P1, then the second default first derivative values q2 can be chosen.
In figure 6, homologous thread A1 and A2 electric current corresponding first derivative curve after a derivation is respectively indicated as
A1 and a2.
It is to be appreciated that curve A1 and A2 mutation are curved in curve a1 and a2 rapidly ascent stage corresponding diagram 5 in Fig. 6
Tune, that is, curve A1 and A2 inflection portions K1 and K2.Mistake already mentioned before, inflection portions K1 and K2 represent the head of screw
Portion comes into contact with the surface of plank.These inflection portions K1 and K2 be used to generate control signal s1 respectively in the microprocessor
With s2 (as shown in Figure 7).As shown in fig. 6, default first derivative values q1, q2 are located at curve a1, a2 rapidly ascent stage respectively.
As shown in fig. 7, when the first default first derivative values q1 is selected, as the first derivative values di/ of current of electric
When dt reaches q1, being now placed in time point t1 the first control signal s1 can be generated by microprocessor.If according at time point
Detection during T1 has determined the second curve A2 of selection, then when first derivative values di/dt reaches the second default first derivative values
During q2, the second control signal s2 positioned at time point t2 is just generated.
According to the first control signal s1 or the second control signal s2 of generation, the rotating speed of the direct current generator of electric tool will
Reduction is even stalled.
That is：In preset time point T1, such as at 1 second or 2 seconds after starting motor, microcomputer reads electricity
Electromechanics stream i.If work head is Screw and/or workpiece is that operating current i now is relatively compared with the plank of softwood matter
Small, the curve that electric current is changed over time is just as the first curve A1 in Fig. 5.The electric current collected in time point T1 is first
Electric current i1, can be 3A or so, and microprocessor will select the first first derivative values q1 (having previously been stored in wherein) to come and electric current
The first derivative di/dt of time is compared.In this way, when di/dt value reaches q1, correspondence time point is t1, correspondence is supplied
Electric current to motor is l1, and now, the first control signal s1 that the rotating speed of motor will be triggered by q1 is controlled and reduction of speed.If
Work head is big screw and/or workpiece is the plank of harder material, and the curve that now electric current is changed over time is just as Fig. 5
In the second curve A2.The the second electric current i2 so collected in time point T1 can be higher than the first electric current i1, for example, i2=
7A.Therefore, in preset time point T1, microprocessor will select the second first derivative values q2 (having previously been stored in wherein).Work as a2
When di/dt values on curve reach q2, correspondence time point is t2, and the electric current of correspondence supply motor is l2, now, the rotating speed of motor
The the second control signal s2 that will be generated is controlled and reduction of speed.
In the second embodiment based on the second inventive principle, the current of electric i in preset time point T1 equally can
It is collected.Now, microprocessor can judge whether the electric current i detected in T1 value can be less than default first threshold values
Current value i1 in P1, such as above-mentioned embodiment, or whether it is higher than default first threshold values P1, but less than default second
Current value i2 in threshold values P2, such as above-mentioned embodiment.If the current value detected is i1, the first curve A1 will be by
It is assigned to a default first derivative values q1；If the current value detected is i2, the second curve A2 will be dispatched to one
Individual larger default first derivative values q2.Next, just as the individual step being previously mentioned in first embodiment, positioned at flex point
K1, K2 first derivative di/dt will be used to generate corresponding control signal s1, s2 again by microprocessor.
It should be noted that only one of which pre-set threshold value P1 is used in the first embodiment, and implement second
There are two pre-set threshold values P1, P2 to be used in mode.
This can also be equally applied in second embodiment：If work head is very big screw and/or work
The material of part is stone, and microprocessor can be equally using to the 3rd threshold values P3 (as shown in Figure 5) being set in advance in it and
Three first derivative values q3 (as shown in Figure 6).It should be noted that these threshold values P1, P2, P3 and these first derivative values q1,
Q2, q3 are stored beforehand in microprocessor, in preset time point T1, according to the different current value i1 detected, i2,
I3 and individually waken up respectively.Certainly, visual situation uses more threshold values P and first derivative values q.
These threshold values P and first derivative values q can be (for example, the screw of test different size by a series of test
It is operated on unlike material or the workpiece of specification) and obtain and have previously been stored in microprocessor.
Electric tool 2 shown in Fig. 8, such as electric screw driver has used the above-mentioned embodiment party based on the second inventive principle
Formula is operated.Wherein, the embodiment shown in most of elements and Fig. 4 is same or like seemingly, so, these elements are used
Identical label.
The work package 4 of electric screw driver shown in Fig. 8 right side includes direct current generator 6, and instrument is clamped in for driving
Work first 8 on chuck 10.It is connected between hammer 10 and motor 6 by a mechanical type spring with clutch system 12.Work
Making first 8 is used to rotate a screw 14 to be screwed into 16 in plank.Power supply 18 is dc source, can be rechargeable battery, can
The DC current i of motor 6 is supplied when trigger 20 is closed.
Electronic-controlled installation 22 and the sensor 24 for detecting electric current are connected between power supply 18 and motor 6.Electric current is passed
Sensor 24 can the motor of detection supply in real time electric current, while the generation signal proportional with the electric current that detects and passing to
Derivation unit 26.Derivation unit 26 subsequently generates a signal proportional with the first derivative di/dt of Current versus time.
The output end of derivation unit 26 is connected to a storage and the input of processing unit 32.
Storage in processing unit 32 with storing, as described in above-mentioned first embodiment, single threshold values P1 and
First and second first derivative values q1 and q2.In preset time point T1, if electric current i1 is less than threshold values P1, storage and processing unit
32 the first first derivative values q1 of selection；If electric current i2 is higher than threshold values P1, storage selects the second single order to lead with processing unit 32
Numerical value q2.Wherein the second first derivative values q2 is more than the first first derivative values q1.When the first derivative di/dt reaches first or second
During default first derivative values q1 or q2, generation control signal s1 or s2 corresponding to processing unit 32 are stored.Now, screw head has been
Through the surface for reaching plank.Control signal s1 or s2 are passed to electronic-controlled installation 22 by storage with processing unit 32.The electronics
Control device 22 is used for the electric power for reducing or disconnecting supply motor 6.That is, control signal s1 or s2 are used to make supply
The electric current i of motor is reduced to zero or relatively low value so that motor stalling or rotating speed are substantially zero.In present embodiment
In, control signal s realizes this purpose by electronic control circuit 30.Reduction of speed control to motor can be in pulse signal p
Perform or delay the specific time to perform immediately after generation.Control signal s1 or s2 may also be used for changing electricity
I flow direction is flowed, so that motor is stalled rapidly.
In a preferred embodiment, electronic-controlled installation can include a microprocessor, above-mentioned derivation unit 26, storage
It can pass through with processing unit 32, electronic control circuit 30 or for delayed control signal s delay cell (not shown)
The instruction in microprocessor is solidificated in perform.That is, electronic-controlled installation 22 can be replaced by a microprocessor.
Shown in Fig. 9-11 is the control method of the present invention and the 3rd inventive principle of electric tool, and it is to be based on Fig. 1-4
Extended out in the first shown inventive principle, therefore, below only in place of both differences of explanation.3rd inventive principle is used
The third time derivation of Current versus time reduces the rotating speed of electric tool 2.
In a specific embodiment, control method may proceed to each step shown in Fig. 1-3.Fig. 9 is the two of Current versus time
The reproduction of secondary derivation curve, the curve was shown in figure 3.As shown in Figure 10, in second dervative d2i/dt2Basis
On, further obtain three order derivative d of Current versus time3i/dt3.After the crest section of three order derivative curves occurs, if
Detect three order derivative value d3i/dt3More than the threshold values v1 provided in advance, and on the occasion of when, control signal s is just generated.
Control signal s is subsequently used in the rotating speed of reduction electric tool 2.
Those skilled in the art can be learnt according to secondary, and control is realized by detecting the derivative of quadravalence, five ranks or higher order
Signal s generation.Because these can all be inferred to easily, applicant is not repeating herein.
Circuit with reference to shown in Figure 11, it should be noted that the signal that secondary derivation unit 28 is exported has been passed to three times
Derivation unit 34, then generates three order derivative d3i/dt3.With the 3rd derivation element output signal, a positive pulse value p1 quilt
Electronic control circuit 30 is have input, it is considered control signal s.By electronic control circuit 30, control signal s causes supply electricity
The DC current i of machine 6 is reduced or is even disconnected completely.
Need to be noted again that, all component units of electronic-controlled installation 22 can be taken by a microprocessor
Generation.
According in the second embodiment mentioned before, storage can store first derivative values with processing unit 32 in it
Q2, or can comprising some first derivative values q1, q2, q3 ... qn and some threshold values P1, P2, P3 ... Pn is carried out
Processing.
Step and protection device described in Fig. 5-8, which equally have, reaches generation behind the surface of plank 16 on the head of screw 14
Quick and reliable response.The protection device is all realized by electronically.
It should be noted that the first derivative mentioned in the respective embodiments described above, second dervative or higher order derivative and not only
It is limited to the Derivative Definition in pure mathematics meaning, can also includes simple etc. based on the progress of derivative principle in practical engineering application
Effect conversion.For example, first derivative can also be expressed as the curent change Δ i in continuous time interval Δ t, i.e. Δ i/ Δs t.For
Facilitate engineer applied, Δ t can be taken as to a very small equivalence, such as Δ t=10ms, so, it is only necessary to constantly judge electricity
Stream i difference, which can just be realized, is equivalent to the computing for seeking first derivative.For example, detecting electricity in continuous Fixed Time Interval point
Flow valuve is i1, i2, i3, i4, i5 ..., and so corresponding first derivative is i2-i1, i3-i2, i4-i3, i5-i4 ..., second order
Derivative is i3-2i2+i1, i4-2i3+i2, i5-2i4+i3 ....Also, in this way, it may not be necessary to try to achieve in advance
First derivative and directly obtain second dervative.Analogize accordingly, the similar equivalent transformation made to higher order derivative is included in this
In invention in the implication of derivative.
It is discussed below based on second dervative or higher order derivative to generate another embodiment of control signal.With second order
Exemplified by derivative, electric screw driver operationally can meet some abnormal conditions sometimes and cause operating current to occur improper dash forward
Become, so that the second dervative obtained is disturbed.These abnormal conditions such as, when screw runs into wood during plank is screwed into
Knot in plate and cause electric current to raise suddenly；Or electric current is substantially increased and flat being also introduced into suddenly when motor just starts
Just detected during the steady phase；Or when using dc-battery bag as power supply, under battery bag causes voltage rapid because putting excessively
Drop, and then electric current is undergone mutation；Or unexpected shake occurs user for arm in use, and electric current is caused to be dashed forward
Become.If screw is not fully screwed into plank also when above-mentioned situation occurs, two obtained are calculated according to Current versus time at this moment
Order derivative is possible to produce interference, that is to say, that the second dervative now generated may can also meet or exceed pre-set threshold value v
(as shown in Figure 3), and now control assembly, electronic-controlled installation 22 as shown in Figure 4, will be mistakenly considered screw
It is fully screwed into plank and cuts off the electric power for supplying motor, this is clearly that user is unwilling what is seen.
When running into above-mentioned abnormal conditions, current value when current value now is often fully screwed into plank compared to screw is wanted
It is small, so to solve the above problems, control assembly can by the value of second dervative and corresponding current value (i.e. using this current value as
Value that is basic and accordingly calculating the obtained second dervative) product is carried out, and a new threshold values is preset for the product value, when this
The product of second dervative and phase induced current be on the occasion of and numerical value be more than or equal to new threshold values when generate corresponding control signal and drop
The speed of low motor or shutdown.Obviously, new threshold values is more much bigger than former threshold values v, in this way so that actually want to
Gap between second dervative and the second dervative for producing interference is exaggerated, and will be actually wanted to thereby using bigger threshold values
Second dervative is screened.Certainly in other embodiments, can be solid by electric current or first derivative or second dervative and one
The product of the n powers of the product of permanent number, electric current or first derivative or second dervative, electric current and corresponding first derivative, second order are led
Number and product, the second dervative of corresponding first derivative add with corresponding first derivative and the product of electric current, single order or second dervative
It is upper some level off to 90 value after ask tan value (such as tan (89+ single orders or second dervative)), single order or second dervative again
Cotangent value (such as ctan (single order or second dervative)) or by the truth of a matter and numerical value 1 of arbitrary value a with single order or second dervative
Difference is compared for the logarithmic function value (such as loga (1- single orders or second dervative)) of antilog with corresponding threshold values, when above-mentioned value
When being more than or equal to its corresponding threshold values (threshold values is a positive number) on numerical value (i.e. absolute value), reduction is generated control signals to
The speed of motor or shutdown.Those of ordinary skill in the art can readily occur in when, above-mentioned embodiment is similarly applied to
Higher derivative, applicant is no longer repeated herein.
In above-mentioned embodiment, output shaft (i.e. Fig. 8 and Figure 11 middle positions are represented using the electric current of motor as detection parameter
Connecting shaft between chuck 10 and clutch system 12) load, that is to say, that when screw is during plank is screwed into,
Output shaft can be by the moment of resistance, by detecting that electric current can just reflect the change of the moment of resistance, so as to judge whether screw is complete
It is screwed into plank.Certainly, those skilled in the art can readily occur in, for representing that the parameter for exporting axle load is not limited to
Electric current, can also be voltage, such as detect the ohmically pressure drop connected with motor；Either rotating speed, is such as examined using Hall effect
Element (Hall Sensor) is surveyed to detect the rotating speed of motor or output shaft；Or the efficiency of motor, as by calculating motor
Export with input power ratio to detect the efficiency of motor.
Figure 12 to Figure 15 discloses a kind of specific detection mode.As shown in figure 12, in the present embodiment, or with electricity
Exemplified by dynamic screwdriver 2, it include casing 5, the motor being arranged in casing 6, output shaft 9, be connected to motor 6 and output shaft 9 it
Between gear reduction 7 and the chuck 10 that is arranged on output shaft 9.In the present embodiment, gear reduction 7 is
Three-stage planetary gear reducing gear, it includes first, second and third planet carrier 71,72,73, is arranged on some on corresponding planet carrier
First, second and third planetary gear 711,721,731, and be arranged on corresponding some planetary gear peripheries first, second and third gear ring 712,
722、732.In present embodiment, a torsion spring 51 is arranged between the gear ring 732 of casing 5 and the 3rd, wherein one end of torsion spring 51 and
Casing 5 is relatively fixed setting, and the other end and the 3rd gear ring 732 are fixedly connected.When the load suffered by output shaft 9 changes,
3rd gear ring 732 can overcome the torsion of torsion spring 51 and rotate.Sensor cluster 24 is similarly disposed at the gear ring 732 of casing 5 and the 3rd
Between.As shown in Figure 13 structure for amplifying, sensor cluster 24 includes the sensing member 241 being fixedly installed on casing 5, and fixed
It is arranged in the moving member 242 on the 3rd gear ring 732, present embodiment, sensing member 241 is preferably photoelectric sensor, moving member
242 be preferably the blanking disc of annular.Coordinate shown in Figure 14, blanking disc 242 includes being uniformly arranged circumferentially multiple logical
Hole 2421, in addition, shown in Figure 15, blanking disc 242 can also use light transmissive material to be made, on the circumference of blanking disc 242
It is even to be provided with multiple lighttight stripeds 2422.
When the 3rd gear ring 732 produces rotation, it can drive blanking disc 242 to be rotated relative to photoelectric sensor 241, so that light
The light that electric transducer 241 is sent will be blocked disk 242 and cover, or through the through hole 2421 of blanking disc 242, photoelectric sensing
Device 241 records the number of the through hole 2421 passed through and generates pulse signal (each pulse represents angular displacement, i.e. angular displacement
Amount/pulse), the signal passes to control assembly, and pulse signal is converted into corresponding angular displacement by control assembly by calculating
Amount, while the moment of torsion suffered by obtaining torsion spring 51 that is multiplied according to the rigidity (moment of torsion/angle) of torsion spring 51 with angular displacement, so as to draw
The size of load torque suffered by output shaft 9.In the present embodiment, obtained by detecting gear ring with respect to the displacement of casing
The load torque of output shaft, certainly in other embodiments, can also be by detecting that ring gear acts on the pressure of casing (such as
By pressure sensor), or detect the rotating speed (Hall detecting element) of planet carrier to represent or further calculate output shaft
The size of load torque.
Above-mentioned to be illustrated by taking electric screw driver as an example, certainly, control method of the invention can also be applied to other electricity
Power driven tools, such as electric drill, electric wrench.Due to this application for the ordinary skill in the art, can be by above-mentioned
Embodiment is realized easily, so applicant is no longer repeated herein.
Claims (8)
1. a kind of control method of electric tool, wherein electric tool include motor and the output shaft by motor rotation driving, institute
Stating output shaft is used to export rotation torque to drive work head to work on workpiece, it is characterised in that the control method includes
Following steps：
Measure the parameter for being used for representing to export axle load changed over time；
Obtain the first derivative of the parameters versus time；
Obtain the second dervative or higher derivative of the parameters versus time；
According to the product of the product or the first derivative and higher derivative of the first derivative and second dervative
Generate corresponding control signal；And
Change the output of the output shaft according to the control signal.
2. control method according to claim 1, it is characterised in that：The parameter is the electric current of supply electric tool.
3. control method according to claim 1, it is characterised in that：The parameter for output rotating speed, the voltage of motor,
One in motor speed or electric efficiency.
4. control method according to claim 1, it is characterised in that：The electric tool also includes casing and is housed in machine
Planetary gear mechanism in shell, the planetary gear mechanism include planet carrier, set planet carrier on planetary gear,
The gear ring set around planetary gear；The parameter is the rotating speed of planet carrier, gear ring acts on casing with respect to the displacement of casing, gear ring
Pressure in one.
5. control method according to claim 1, it is characterised in that：Also wrapped the step of generating corresponding control signal before
Include and preset pre-set threshold value, when the product of the product or the first derivative and higher derivative of first derivative and second dervative is big
Corresponding control signal is generated when the pre-set threshold value.
6. control method according to claim 1, it is characterised in that：The control signal is led when first derivative with second order
Several products or the product of the first derivative and higher derivative are when being more than or equal to pre-set threshold value immediately or in predetermined delay
Generated after time.
7. a kind of electric tool, it is characterised in that the electric tool includes：
Output shaft, for driving work head, so that work head has rotary speed；
Motor, output shaft described in rotation driving；
Power supply, for supplying the motor electric power；
Sensor, the parameter of output shaft load is represented for measuring；
Control assembly, is used for
Obtain the first derivative of the parameters versus time；
Obtain the second dervative or higher derivative of the parameters versus time；
It is corresponding with the product or the first derivative of second dervative and the product generation of higher derivative according to the first derivative
Control signal；
Change the output of the output shaft according to the control signal.
8. electric tool according to claim 7, it is characterised in that：The control assembly is stored with pre-set threshold value, when one
When the product of the product or the first derivative and higher derivative of order derivative and second dervative is more than or equal to the pre-set threshold value,
The control assembly generates corresponding control signal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410624039.0A CN104485860B (en) | 2009-01-04 | 2009-01-04 | The control method of electric tool and the electric tool for performing the control method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410624039.0A CN104485860B (en) | 2009-01-04 | 2009-01-04 | The control method of electric tool and the electric tool for performing the control method |
| CN200910001862.5A CN101771379B (en) | 2009-01-04 | 2009-01-04 | Control method of electric tool and electric tool executing same |
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| Application Number | Title | Priority Date | Filing Date |
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| CN200910001862.5A Division CN101771379B (en) | 2009-01-04 | 2009-01-04 | Control method of electric tool and electric tool executing same |
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| CN104485860A CN104485860A (en) | 2015-04-01 |
| CN104485860B true CN104485860B (en) | 2017-08-22 |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106483846B (en) * | 2015-09-01 | 2019-12-13 | 苏州宝时得电动工具有限公司 | Control method of electric tool and electric tool for executing control method |
| CN105818088B (en) * | 2016-03-14 | 2017-09-08 | 郑州时享电子技术有限公司 | The number of shocks detection method and device of impact type fastening tool |
| KR102393070B1 (en) * | 2017-12-08 | 2022-05-03 | 커넥텍 재팬 가부시키가이샤 | Tool, work management device, work management method and work management system |
| CN109995307A (en) * | 2017-12-29 | 2019-07-09 | 苏州宝时得电动工具有限公司 | The control method of electric tool and the electric tool for executing the control method |
| CN114871983B (en) * | 2022-05-18 | 2023-11-24 | 深圳市冠腾达科技有限公司 | Electric screw driver control method and system, computer storage medium and program product |
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| US4418765A (en) * | 1981-01-16 | 1983-12-06 | Matsushita Electric Industrial Company, Limited | Power-driven screwdriver with a torque control |
| CN1962199A (en) * | 2005-11-08 | 2007-05-16 | 车王电子股份有限公司 | Electric tool |
| CN201093036Y (en) * | 2007-08-31 | 2008-07-30 | 苏州宝时得电动工具有限公司 | Speed changing tool |
| CN101247100A (en) * | 2007-02-16 | 2008-08-20 | 苏州宝时得电动工具有限公司 | Electric tool control method and electric tool using the same |
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2009
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4418765A (en) * | 1981-01-16 | 1983-12-06 | Matsushita Electric Industrial Company, Limited | Power-driven screwdriver with a torque control |
| CN1962199A (en) * | 2005-11-08 | 2007-05-16 | 车王电子股份有限公司 | Electric tool |
| CN101247100A (en) * | 2007-02-16 | 2008-08-20 | 苏州宝时得电动工具有限公司 | Electric tool control method and electric tool using the same |
| CN201093036Y (en) * | 2007-08-31 | 2008-07-30 | 苏州宝时得电动工具有限公司 | Speed changing tool |
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