CN108931328A - A kind of joint of robot torque sensor - Google Patents
A kind of joint of robot torque sensor Download PDFInfo
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- CN108931328A CN108931328A CN201810343497.5A CN201810343497A CN108931328A CN 108931328 A CN108931328 A CN 108931328A CN 201810343497 A CN201810343497 A CN 201810343497A CN 108931328 A CN108931328 A CN 108931328A
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- voltage signal
- torsional spring
- npn silicon
- silicon phototransistor
- plane
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L3/00—Measuring torque, work, mechanical power, or mechanical efficiency, in general
- G01L3/02—Rotary-transmission dynamometers
- G01L3/14—Rotary-transmission dynamometers wherein the torque-transmitting element is other than a torsionally-flexible shaft
- G01L3/1407—Rotary-transmission dynamometers wherein the torque-transmitting element is other than a torsionally-flexible shaft involving springs
- G01L3/1421—Rotary-transmission dynamometers wherein the torque-transmitting element is other than a torsionally-flexible shaft involving springs using optical transducers
Abstract
The invention discloses a kind of joint of robot torque sensors.Traditional sensors are present in joint drive structure as individual member, increase the cost of complexity and torque measurement.The present invention fixes NPN silicon phototransistor and infrared light-emitting diode on the first plane torsional spring, PCB signal processing circuit board is amplified and is filtered to four NPN silicon phototransistor transmission tetra- road voltage signals of Lai, analog voltage after filtering processing is converted to digital voltage signal, linearity correction is carried out to four railway digital voltage signals using the algorithm of least square method linear fit, then four railway digital voltage signals after linearity correction are subjected to calibration decoupling processing, so that corresponding voltage value is converted to torque value.Hysteresis error of the present invention and temperature drift errors are small, and measurement accuracy is high, while reducing influence of the torque sensor to flexibility of joint.
Description
Technical field
The invention belongs to joint of robot to measure torque sensor technology field, and in particular to one kind is used for joint of robot
The integrated form torque sensor of place's measurement plane torsion spring torque.
Background technique
In machine driven system, torque is one of the important parameter of reaction system performance.For being passed at joint of robot
The flexibility of joint drive may be implemented in dynamic driving unit-double layer planar torsional spring (application number 201611059925.9), reduces
Joint transmission rigidity.In the transmission process of plane torsional spring, the torque and corner information that plane torsional spring is born are that robot closes
The essential part of drive control is saved, and power or torque sensor are the necessary sensors for perceiving torque information suffered by torsional spring
Part.
In traditional sensor design, sensor is present in joint drive structure as an independent component, this
Kind sensor design increases the complexity of joint structure and the cost of torque measurement.And the use in plane torsional spring is used to answer
The method (patent No. CN105606279A) for becoming piece measurement torque is influenced vulnerable to factors such as temperature, humidity and fatigues, is caused late
Stagnant error, repeatability error, temperature drift error is larger, reduces sensor accuracy class.
Summary of the invention
In view of the above-mentioned deficiencies in the prior art, it is an object of the present invention to provide a kind of plane torsional spring integrated optical sensor, solve
The problems such as certainly traditional sensors hysteresis error and temperature drift errors are big, and measurement accuracy is low, while reducing torque sensor pair
The influence of flexibility of joint.
In order to achieve the above object, the technical solution adopted by the present invention is as follows：
The present invention includes end cap one, splined shaft, the first plane torsional spring, the second plane torsional spring, end cap two, PCB signal processing
Circuit board and light-sensitive device；PCB signal processing circuit board is mounted on one inside of end cap.
The structure of the first plane torsional spring and the second plane torsional spring is completely the same, includes inner ring, outer ring and elastomer
Unit；Transition plane is equipped between that side that first boss is not connected with elastomer unit and outer ring；In four first boss, phase
Angle between the transition plane and outer ring end face of adjacent two of them first boss isAnd this two
The transition plane of a first boss is towards the different ends of outer ring；The transition plane of other two first boss and outer ring end face are hung down
Directly；The splined hole of the splined hole of the inner ring of first plane torsional spring and the second plane torsional spring and end cap two with spline axis connection,
The center hole of end cap one is nested on splined shaft；Mounting hole and end on the outer ring of first plane torsional spring and the second plane torsional spring
The mounting hole of lid one and driver output is bolted；First plane torsional spring and the second plane torsional spring are oppositely arranged.
The light-sensitive device includes infrared light-emitting diode and NPN silicon phototransistor；Four of first plane torsional spring
NPN silicon phototransistor is respectively and fixedly provided in the transition plane of first boss；On four elastomer units of the first plane torsional spring
It is fixed with infrared light-emitting diode, the receiving end of the transmitting terminal of each infrared light-emitting diode and a NPN silicon phototransistor
It is oppositely arranged, and the first plane torsion spring torque is under nought state, the transmitting light optical axis and NPN silicon photoelectricity of infrared light-emitting diode are brilliant
The angle that the central axis of body pipe projects on outer ring end face is θ, θ=165 °；NPN silicon phototransistor receives infraluminescence two
The transmitting light of pole pipe, and voltage signal is sent to PCB signal processing circuit board.
Line between the launch point of the infrared light-emitting diode and the receiving point of NPN silicon phototransistor is d, infrared
The transmitting light optical axis of light emitting diode and the angle of line d are α, the central axis of NPN silicon phototransistor and the angle of line d
For β, α=7 °, β=8 °.
Power supply circuit in the PCB signal processing circuit board is supplied to infrared light-emitting diode and NPN silicon phototransistor
Electricity；PCB signal processing circuit board to four NPN silicon phototransistors transmission tetra- road voltage signals of Lai amplify and filtering at
Reason；ADUC7022 microcontroller in PCB signal processing circuit board have A D conversion module, by the simulation electricity after filtering processing
Pressure is converted to digital voltage signal.ADUC7022 microcontroller is using the algorithm of least square method linear fit to four railway digitals electricity
Signal is pressed to carry out linearity correction.Then, the dsp chip in ADUC7022 microcontroller is by four railway digital voltages after linearity correction
Signal carries out calibration decoupling processing, so that corresponding voltage value is converted to torque value.
The filtering processing is using first-order low-pass wave circuit.
The linearity correction process is specific as follows：With the plane parallel with the first plane torsional spring end face for the face XOY, Z axis
Vertical first plane torsional spring end face, the first plane torsional spring center are coordinate origin, establish coordinate system；In driver output or flower
Apply the power F of equivalent variation on X, Y of key axis, Z-direction respectivelyx、Fy、Fz, alternatively, being applied on driver output or splined shaft
Add the torque M of Z-directionz, then with measurement Fx、Fy、FzOr MzCorresponding NPN silicon phototransistor voltage signal corrected value and Fx、
Fy、FzOr MzRelationship a linear equation unify formula u=A*F+B expression；Wherein, coefficient A, B is quasi- by least square linear
Conjunction acquires, and F represents Fx、Fy、FzOr Mz, u represents u1、u2、u3Or u4；u1Characterization measurement FxNPN silicon phototransistor in Fx、Fy、
FzOr MzUnder effect it is calibrated after voltage signal output valve；u2Characterization measurement FyNPN silicon phototransistor in Fx、Fy、FzOr Mz
Under effect it is calibrated after voltage signal output valve；u3Characterization measurement FzNPN silicon phototransistor in Fx、Fy、FzOr MzEffect
Under it is calibrated after voltage signal output valve；u4Characterization measurement MzNPN silicon phototransistor in Fx、Fy、FzOr MzThe lower warp of effect
Voltage signal output valve after correction.
Only consider the power F in X, Y, Z axis directionx、Fy、FzTo MzCoupled interference, calibration decoupling treatment process it is as follows：Through school
The road Zheng Houmei voltage signal output valve u1、u2、u3Or u4Subtract remaining each road voltage signal bring interference in addition to itself
Power retinoic acid syndrome error amount, just eliminates retinoic acid syndrome error.The road Hou Mei voltage signal is corrected to believe remaining each road voltage
Number bring perturbed force retinoic acid syndrome error amount and corresponding Fx、Fy、FzOr MzIt is directly proportional, but due to Fx、Fy、FzOr MzFor
Unknown number to be measured, so with corresponding u1、u2、u3、u4Instead of Fx、Fy、FzOr Mz, secondary coupling error is introduced, after obtaining correction
Every road voltage signal for remaining each road voltage signal bring perturbed force retinoic acid syndrome error amount；To establish Fx、Fy、Fz、
MzDecoupling function it is as follows, decouple function in, although introducing secondary coupling error, the percentage of the road Dan Zhanmei voltage signal is very
It is small, influence of the secondary coupling error to every road voltage signal values is not considered：
Wherein, kij, i=1,2,3,4, j=1,2,3,4 be the coefficient of coup, and solution formula is as follows：
Wherein, b12、b13And b14Respectively FxEffect is lower to export u2、u3And u4NPN silicon phototransistor corresponding to it is residual
Remaining zero drift value, b21、b23And b24Respectively FyEffect is lower to export u1、u3And u4NPN silicon phototransistor corresponding to it is residual
Remaining zero drift value, b31、b32And b34Respectively FzEffect is lower to export u1、u2And u4NPN silicon phototransistor corresponding to it is residual
Remaining zero drift value, b41、b42And b43Respectively MzEffect is lower to export u1、u2And u3NPN silicon phototransistor corresponding to it is residual
Remaining zero drift value；All remnants zero drift value numerical value very littles, ignore here.Final torque is calculated using following formula：
Mz=k44(u4-k14u1-k24u2-k34u3) (6)
Formula (2) to formula (5) is obtained by rating test, specific as follows：In driver output or X, Y, Z of splined shaft
Apply the power F of equivalent variation on direction respectivelyx、Fy、Fz, alternatively, applying the power of Z-direction on driver output or splined shaft
Square Mz, each NPN silicon phototransistor measures and the calibrated road Hou Ge voltage signal output valve when recording load every time, and will
FxThe corresponding road the correction Hou Ge voltage signal output valve of each NPN silicon phototransistor is fitted to obtain with least square method when load
Formula (2), by FyThe each NPN silicon phototransistor corresponding road correction Hou Ge voltage signal output valve least square method when load
Fitting obtains formula (3), by FzThe corresponding road the correction Hou Ge voltage signal output valve of each NPN silicon phototransistor is with most when load
Small square law is fitted to obtain formula (4), by MzThe corresponding road the correction Hou Ge voltage signal of each NPN silicon phototransistor is defeated when load
Value is fitted to obtain formula (5) with least square method out, to solve coefficient of coup kijBest estimate.
The beneficial effects of the invention are as follows：
1, since the present invention is the integrated torque sensor in plane torsional spring, so not needing end resolving, pass is not increased
Section is flexible, and working method is simple, and measurement efficiency is high, and instantaneity is good.
2, due to light-sensitive device, in arrangement, initial position carried out optimization, and the selection of the initial position is located at light-sensitive device
The position sensitive to torsional spring corner, improves the sensitivity of sensor.
3, signal acquisition uses four pairs of light-sensitive devices, point four tunnels acquisition torque caused voltage letter between Sensitive Apparatus
Number, and pass through amplifying circuit, after the processing of filter circuit, the high frequency impurity signal passed through in circuit is eliminated, while eliminating torque
Caused vibration in mechanism improves the reliability and stability of torque voltage signal, its excess-three road can in four road signals
With for detecting other direction force signals in addition to axial torque, and calibration decoupling is carried out in the processor, to reduce axial direction
The error of torque measurement.
4, the present invention passes through linearity correction, so that sensor can obtain preferable linear result in torque measurement；Pass through
Least square method linear fit carries out non-linear partial correction, improves measurement accuracy.
5, the present invention is embedded in the measurement of optical sensitive device wherein and turns round using plane torsional spring as the ontology of sensor design
Square has light weight, the advantages such as small in size；Elastomer unit caused by torque suffered by plane torsional spring deformation, by inner and outer rings it
Between relative displacement amplification after, should become larger, with elastomer unit replace sensor elastomer, do not change joint structure, rigidity and
Flexibility, and optical device is influenced small by environment temperature and fatigue, improves measurement accuracy.
Detailed description of the invention
Fig. 1 is structural perspective of the invention.
Fig. 2 is the voltage signal extraction figure after each NPN silicon phototransistor is calibrated in the present invention.
Fig. 3 is light-sensitive device position figure of the invention.
Fig. 4 is the relative position schematic diagram of infrared light-emitting diode and NPN silicon phototransistor in the present invention.
Fig. 5 is the performance diagram of light-sensitive device in the present invention.
Fig. 6 is that the first plane torsional spring or the second plane torsional spring bear torque and inner and outer rings relative torsional angle in the present invention
Graph of relation.
Fig. 7 is the structure chart of first-order low-pass wave circuit in the present invention.
In figure：1, end cap one, 2, splined shaft, the 3, first plane torsional spring, 4, NPN silicon phototransistor, the 5, second plane are turned round
Spring, 6, end cap two, 7, infrared light-emitting diode.
Specific embodiment
To make the object, technical solutions and advantages of the present invention clearer, invention is further retouched with reference to the accompanying drawing
It states.
As shown in Figure 1, a kind of joint of robot torque sensor of the present invention, is turned round by end cap 1, splined shaft 2, the first plane
Spring 3, the second plane torsional spring 5, end cap 26, PCB signal processing circuit board and light-sensitive device composition；End cap 1 is for installing PCB
Signal processing circuit board.
As shown in Figures 2 and 3, the structure of the first plane torsional spring 3 and the second plane torsional spring 5 is completely the same, is for application
First plane torsional spring or the second improved structure of plane torsional spring in numbers 201611059925.9 patent, i.e., include inner ring,
Outer ring and elastomer unit, but do not include tie-down cable, and the shape of first boss changes；The change in shape of first boss has
Body is as follows：That side structure that first boss is connected with elastomer unit changes and (can not also do and change, this part-structure does not produce
Raw substantial effect), transition plane is equipped between that side that first boss is not connected with elastomer unit and outer ring；Four first
In boss, wherein the angle between the transition plane of two neighboring first boss and outer ring end face is And it should
The transition plane of two first boss does not exist towards the different ends of outer ring, the i.e. exterior normal of the transition plane of two first boss
In same plane；The transition plane of other two first boss is vertical with outer ring end face；First plane torsional spring and the second plane are turned round
The splined hole of the inner ring of spring and the splined hole of end cap 26 are connect with splined shaft 2, and the center hole of end cap 1 is nested in flower
On key axis 2；Splined shaft is connect with joint driver active part；Peace on the outer ring of first plane torsional spring and the second plane torsional spring
Dress hole and the mounting hole of end cap one and driver output are bolted；5 phase of first plane torsional spring 3 and the second plane torsional spring
To setting, i.e. circumferential position is corresponding on the first plane torsional spring 3 and the second plane torsional spring 5 and the transition of angle is equipped with outer ring end face
Plane is towards inconsistent；The deformation that the torque that first plane torsional spring 3 and the second plane torsional spring 5 are born passes through elastomer unit
Light-sensitive device is passed to for the relative angular displacement of inner and outer rings.
As shown in figure 4, light-sensitive device includes infrared light-emitting diode (LED) 7 and NPN silicon phototransistor (PD) 4；First
NPN silicon phototransistor 4 is respectively and fixedly provided in the transition plane of four first boss of plane torsional spring；Four of first plane torsional spring
Infrared light-emitting diode, the transmitting terminal of each infrared light-emitting diode and a NPN silicon photoelectricity are respectively and fixedly provided on elastomer unit
The receiving end of transistor is oppositely arranged, and 3 torque of the first plane torsional spring is the transmitting light light of infrared light-emitting diode under 0 state
The angle that the central axis of axis and NPN silicon phototransistor projects on outer ring end face is θ, θ=165 °；NPN silicon photoelectric crystal
Pipe receives the transmitting light of infrared light-emitting diode, thus by the mechanical signal of the inner and outer rings relative angular displacement of the first plane torsional spring 3
It is changed into voltage signal, is sent to PCB signal processing circuit board.
Torque is reached elastomer unit by the load rotation of driver output when work, or input driving torque reaches flower
Key axis and elastomer unit can load elastomer unit, so that the rotation of the either side of input and load can be direct
Drive the rotation of another party；Wherein, each elastomer unit generates series connection flexible deformation, buffering and accumulation of energy through flexible deformation
Afterwards, then by the torque after conversion input or load are transmitted to.
It is torque suffered by the first plane torsional spring that the present invention, which measures target, but only according to finite element result and experimental data point
Analysing plane torsional spring, (i.e. plane torsional spring bears torque and inner and outer rings relative torsion angular dependence is substantially in line with the good linearity
Property variation) when, on the first plane torsional spring add light-sensitive device just have application value.It is illustrated in figure 6 the present embodiment use
First plane torsional spring or the second plane torsional spring bear the relation curve of torque T and inner and outer rings relative torsional angle γ.
It is illustrated in figure 5 the graph of relation that the response voltage value of NPN silicon phototransistor voltage signal changes with θ, it can
See, when θ is less than 150 °, the response voltage value of NPN silicon phototransistor (model SDP8436) voltage signal is almost nil,
In θ=180 °, it is maximum that NPN silicon phototransistor responds voltage value, and when θ=165 °, and response voltage value is that response voltage is maximum
The 65% of value；Curve slope at θ=165 ° reaches maximum value, and at this moment, light-sensitive device is meeting the first plane torsional spring range
Under the premise of it is most sensitive to deforming at θ=165 °, and sensor can be detected in the first plane torsional spring positive and negative rotation it is dull
Voltage signal.Line between the launch point of infrared light-emitting diode and the receiving point of NPN silicon phototransistor is d, infrared hair
The transmitting light optical axis of optical diode and the angle of line d are α, and the angle of the central axis and line d of NPN silicon phototransistor is
β, according to the nominal of selected infrared light-emitting diode (model SEP8736) and NPN silicon phototransistor (model SDP8436)
Angular aperture is respectively 6.8 ° and 8.2 °, and selecting the preferable value of α and β is respectively α=7 ° and β=8 °.
Power supply circuit in PCB signal processing circuit board is powered to infrared light-emitting diode and NPN silicon phototransistor；
PCB signal processing circuit board is amplified and is filtered to four NPN silicon phototransistor transmission tetra- road voltage signals of Lai；
ADUC7022 microcontroller in PCB signal processing circuit board have A D conversion module, the analog voltage after filtering processing is turned
It is changed to digital voltage signal.ADUC7022 microcontroller believes four railway digital voltages using the algorithm of least square method linear fit
Number carry out linearity correction, improve measurement accuracy.Then, the dsp chip in ADUC7022 microcontroller is by four after linearity correction
Railway digital voltage signal carries out calibration decoupling processing, so that corresponding voltage value is converted to torque value.Calibration decoupling is processed
Journey includes eliminating the process of retinoic acid syndrome error, and obtain the process of decoupling function by rating test.
Wherein, it is filtered to inhibit extraneous High-frequency Interference and the first plane torsional spring to vibrate using first-order low-pass wave circuit
Caused frequency content allows direct current and low frequency signal to pass through, and cutoff frequency is 1/ (2 π RC)；Specific cutoff frequency is with reality
Change using the resistance R of selection, capacitor C value size, as shown in fig. 7, first-order low-pass wave circuit uses voltage follower, band is negative
Loading capability is strong, wherein Ui is the input voltage of voltage follower, and U is the output voltage of voltage follower.
Linearity correction process is specific as follows：With the plane parallel with 3 end face of the first plane torsional spring for the face XOY, Z axis vertical the
One plane torsional spring end face, 3 center of the first plane torsional spring are coordinate origin, establish coordinate system；In driver output or splined shaft
X, Y, apply the power F of equivalent variation in Z-direction respectivelyx、Fy、Fz, alternatively, applying the side Z on driver output or splined shaft
To torque Mz, then with measurement Fx、Fy、FzOr MzCorresponding NPN silicon phototransistor voltage signal corrected value and Fx、Fy、FzOr
MzRelationship a linear equation unify formula u=A*F+B expression, the voltage signal of each NPN silicon phototransistor is using correction
Value guarantees that measurement accuracy and the linearity get a promotion before calibration decouples；Wherein, coefficient A, B is asked by least square linear fit
, F represents Fx、Fy、FzOr Mz, u represents u1、u2、u3Or u4；u1Characterization measurement FxNPN silicon phototransistor in Fx、Fy、FzOr Mz
Under effect it is calibrated after voltage signal output valve；u2Characterization measurement FyNPN silicon phototransistor in Fx、Fy、FzOr MzEffect
Under it is calibrated after voltage signal output valve；u3Characterization measurement FzNPN silicon phototransistor in Fx、Fy、FzOr MzThe lower warp of effect
Voltage signal output valve after correction；u4Characterization measurement MzNPN silicon phototransistor in Fx、Fy、FzOr MzIt is calibrated under effect
Voltage signal output valve afterwards.
Calibration decoupling treatment process is following (only to consider the power F in X, Y, Z axis direction in the present embodimentx、Fy、FzTo Mz's
Coupled interference)：The calibrated road Hou Mei voltage signal output valve u1、u2、u3Or u4Subtract remaining each road voltage in addition to itself
Signal bring perturbed force retinoic acid syndrome error amount, just eliminates retinoic acid syndrome error.Correct the road Hou Mei voltage signal for
Remaining each road voltage signal bring perturbed force retinoic acid syndrome error amount and corresponding Fx、Fy、FzOr MzIt is directly proportional, but by
In Fx、Fy、FzOr MzFor unknown number to be measured, so with corresponding u1、u2、u3、u4Instead of Fx、Fy、FzOr Mz, introduce two secondary couplings
Error obtains the correction road Hou Mei voltage signal for remaining each road voltage signal bring perturbed force retinoic acid syndrome error amount；
To establish Fx、Fy、Fz、MzDecoupling function it is following (in decoupling function, although introducing secondary coupling error, the road Dan Zhanmei voltage
The percentage very little of signal does not consider influence of the secondary coupling error to every road voltage signal values)：
Wherein, kij, i=1,2,3,4, j=1,2,3,4 be the coefficient of coup, and solution formula is as follows：
Wherein, b12、b13And b14Respectively FxEffect is lower to export u2、u3And u4NPN silicon phototransistor corresponding to it is residual
Remaining zero drift value, b21、b23And b24Respectively FyEffect is lower to export u1、u3And u4NPN silicon phototransistor corresponding to it is residual
Remaining zero drift value, b31、b32And b34Respectively FzEffect is lower to export u1、u2And u4NPN silicon phototransistor corresponding to it is residual
Remaining zero drift value, b41、b42And b43Respectively MzEffect is lower to export u1、u2And u3NPN silicon phototransistor corresponding to it is residual
Remaining zero drift value；All remnants zero drift value numerical value very littles, ignore here.Final torque is calculated using following formula：
Mz=k44(u4-k14u1-k24u2-k34u3) (6)
Formula (2) to formula (5) is obtained by rating test, specific as follows：In driver output or X, Y, Z of splined shaft
Apply the power F of equivalent variation on direction respectivelyx、Fy、Fz, alternatively, applying the power of Z-direction on driver output or splined shaft
Square Mz, each NPN silicon phototransistor measures and the calibrated road Hou Ge voltage signal output valve when recording load every time, and will
FxThe each NPN silicon phototransistor corresponding road correction Hou Ge voltage signal output valve (u when load1、u2、u3And u4) use minimum two
Multiplication is fitted to obtain formula (2), by FyThe each NPN silicon phototransistor corresponding road correction Hou Ge voltage signal output valve when load
It is fitted to obtain formula (3) with least square method, by FzThe each NPN silicon phototransistor corresponding road correction Hou Ge voltage letter when load
Number output valve is fitted to obtain formula (4) with least square method, by MzIt is each after the corresponding correction of each NPN silicon phototransistor when load
Road voltage signal output valve is fitted to obtain formula (5) with least square method, to solve coefficient of coup kijBest estimate.
In the above process, although introducing signal caused by other dimension power or torque in the design of sensor, its
It ties up voltage signal and is served only for eliminating retinoic acid syndrome error during demarcating decoupling, improves sensor accuracy class, not
To except MzPower or torque other than direction are resolved.
Since sensor of the invention measurement depends on the variation of α and β, PCB signal processing when plane torsional spring zero load
Circuit board detecting to voltage value be by being optimized according to response relation between infrared light-emitting diode and NPN silicon phototransistor
Initial relative position (i.e. θ=165 °) detection afterwards, make transducer sensitivity and output electricity by optimizing initial relative position
Range is pressed to maximize.
Wherein, when plane torsional spring is acted on by torque in the present invention, between infrared light-emitting diode and NPN silicon phototransistor
Distance change it is smaller and be reflected in the curent change of PCB signal processing circuit board, do not do independent consideration to it.
Claims (7)
1. a kind of joint of robot torque sensor, including end cap one, splined shaft, the first plane torsional spring, the second plane torsional spring, end
Lid two, PCB signal processing circuit board and light-sensitive device；PCB signal processing circuit board is mounted on one inside of end cap；Its feature exists
In：The structure of the first plane torsional spring and the second plane torsional spring is completely the same, includes inner ring, outer ring and elastomer unit；
Transition plane is equipped between that side that first boss is not connected with elastomer unit and outer ring；It is adjacent in four first boss
Angle between the transition plane and outer ring end face of two of them first boss is And this two
The transition plane of one boss is towards the different ends of outer ring；The transition plane of other two first boss is vertical with outer ring end face；The
The splined hole of the splined hole of the inner ring of one plane torsional spring and the second plane torsional spring and end cap two with spline axis connection, end cap one
Center hole be nested on splined shaft；Mounting hole on the outer ring of first plane torsional spring and the second plane torsional spring and end cap one and
The mounting hole of driver output is bolted；First plane torsional spring and the second plane torsional spring are oppositely arranged；
The light-sensitive device includes infrared light-emitting diode and NPN silicon phototransistor；Four first of first plane torsional spring
NPN silicon phototransistor is respectively and fixedly provided in the transition plane of boss；It is fixed on four elastomer units of the first plane torsional spring
There is infrared light-emitting diode, the transmitting terminal of each infrared light-emitting diode is opposite with the receiving end of a NPN silicon phototransistor
Setting, and the first plane torsion spring torque is the transmitting light optical axis and NPN silicon phototransistor of infrared light-emitting diode under nought state
The angle that is projected on outer ring end face of central axis be θ, θ=165 °；NPN silicon phototransistor receives infrared light-emitting diode
Transmitting light, and voltage signal is sent to PCB signal processing circuit board.
2. a kind of joint of robot torque sensor according to claim 1, it is characterised in that：Two pole of infraluminescence
Line between the launch point of pipe and the receiving point of NPN silicon phototransistor is d, the transmitting light optical axis of infrared light-emitting diode with
The angle of line d is α, and the central axis of NPN silicon phototransistor and the angle of line d are β, α=7 °, β=8 °.
3. a kind of joint of robot torque sensor according to claim 1, it is characterised in that：The PCB signal processing
Power supply circuit in circuit board is powered to infrared light-emitting diode and NPN silicon phototransistor；PCB signal processing circuit board is to four
A NPN silicon phototransistor transmission tetra- road voltage signal of Lai is amplified and is filtered；In PCB signal processing circuit board
ADUC7022 microcontroller have A D conversion module, the analog voltage after filtering processing is converted into digital voltage signal；
ADUC7022 microcontroller carries out linearity correction to four railway digital voltage signals using the algorithm of least square method linear fit；So
Afterwards, four railway digital voltage signals after linearity correction are carried out calibration decoupling processing by the dsp chip in ADUC7022 microcontroller,
To which corresponding voltage value is converted to torque value.
4. a kind of joint of robot torque sensor according to claim 3, it is characterised in that：The filtering processing is
Using first-order low-pass wave circuit.
5. a kind of joint of robot torque sensor according to claim 3, it is characterised in that：The linearity correction
Journey is specific as follows：With the plane parallel with the first plane torsional spring end face for the face XOY, the vertical first plane torsional spring end face of Z axis, first
Plane torsional spring center is coordinate origin, establishes coordinate system；Apply respectively in X, Y of driver output or splined shaft, Z-direction
The power F of equivalence variationx、Fy、Fz, alternatively, applying the torque M of Z-direction on driver output or splined shaftz, then with measurement Fx、
Fy、FzOr MzCorresponding NPN silicon phototransistor voltage signal corrected value and Fx、Fy、FzOr MzRelationship with unitary linearly side
Cheng Tongyi formula u=A*F+B expression；Wherein, coefficient A, B is acquired by least square linear fit, and F represents Fx、Fy、FzOr Mz, u
Represent u1、u2、u3Or u4；u1Characterization measurement FxNPN silicon phototransistor in Fx、Fy、FzOr MzUnder effect it is calibrated after voltage
Signal value output；u2Characterization measurement FyNPN silicon phototransistor in Fx、Fy、FzOr MzUnder effect it is calibrated after voltage signal
Output valve；u3Characterization measurement FzNPN silicon phototransistor in Fx、Fy、FzOr MzUnder effect it is calibrated after voltage signal output
Value；u4Characterization measurement MzNPN silicon phototransistor in Fx、Fy、FzOr MzUnder effect it is calibrated after voltage signal output valve.
6. a kind of joint of robot torque sensor according to claim 3, it is characterised in that：Only consider X, Y, Z axis side
To power Fx、Fy、FzTo MzCoupled interference, calibration decoupling treatment process it is as follows：The calibrated road Hou Mei voltage signal output valve
u1、u2、u3Or u4Remaining each road voltage signal bring perturbed force retinoic acid syndrome error amount in addition to itself is subtracted, is just eliminated
Retinoic acid syndrome error；The road Hou Mei voltage signal is corrected to miss remaining each road voltage signal bring perturbed force retinoic acid syndrome
Difference and corresponding Fx、Fy、FzOr MzIt is directly proportional, but due to Fx、Fy、FzOr MzFor unknown number to be measured, so with corresponding
u1、u2、u3、u4Instead of Fx、Fy、FzOr Mz, secondary coupling error is introduced, it is each for remaining to obtain the correction road Hou Mei voltage signal
Road voltage signal bring perturbed force retinoic acid syndrome error amount；To establish Fx、Fy、Fz、MzDecoupling function it is as follows, decouple letter
In number, although introducing secondary coupling error, the percentage very little of the road Dan Zhanmei voltage signal does not consider secondary coupling error to every
The influence of road voltage signal values：
Wherein, kij, i=1,2,3,4, j=1,2,3,4 be the coefficient of coup, and solution formula is as follows：
Wherein, b12、b13And b14Respectively FxEffect is lower to export u2、u3And u4NPN silicon phototransistor corresponding to remaining zero point
Drift value, b21、b23And b24Respectively FyEffect is lower to export u1、u3And u4NPN silicon phototransistor corresponding to remaining zero point
Drift value, b31、b32And b34Respectively FzEffect is lower to export u1、u2And u4NPN silicon phototransistor corresponding to remaining zero point
Drift value, b41、b42And b43Respectively MzEffect is lower to export u1、u2And u3NPN silicon phototransistor corresponding to remaining zero point
Drift value；All remnants zero drift value numerical value very littles, ignore here；Final torque is calculated using following formula：
Mz=k44(u4-k14u1-k24u2-k34u3) (6)。
7. a kind of joint of robot torque sensor according to claim 6, it is characterised in that：Formula (2) to formula (5) be by
What rating test obtained, it is specific as follows：Apply equivalent variation respectively in X, Y of driver output or splined shaft, Z-direction
Power Fx、Fy、Fz, alternatively, applying the torque M of Z-direction on driver output or splined shaftz, record each when load every time
NPN silicon phototransistor measures and the calibrated road Hou Ge voltage signal output valve, and by FxEach NPN silicon photoelectricity is brilliant when load
The corresponding road the correction Hou Ge voltage signal output valve of body pipe is fitted to obtain formula (2) with least square method, by FyEach NPN when load
The corresponding road the correction Hou Ge voltage signal output valve of silicon phototransistor is fitted to obtain formula (3) with least square method, by FzLoad
When the corresponding road the correction Hou Ge voltage signal output valve of each NPN silicon phototransistor be fitted to obtain formula (4) with least square method,
By MzThe corresponding road the correction Hou Ge voltage signal output valve of each NPN silicon phototransistor is fitted with least square method when load
To formula (5), to solve coefficient of coup kijBest estimate.
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