CN114061741A - Measuring device and measuring method for measuring resonance frequency of industrial robot - Google Patents
Measuring device and measuring method for measuring resonance frequency of industrial robot Download PDFInfo
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Abstract
The invention discloses a measuring device and a measuring method for measuring the resonance frequency of an industrial robot, wherein the industrial robot comprises a base, N joints and N motors, wherein the N joints and the N motors are sequentially numbered from near to far away from the base and are respectively used for driving the corresponding joints to rotate, and N is more than or equal to 4; the measuring device comprises an end plate connected with the Nth joint, m three-way accelerometers, a multi-channel dynamic signal analyzer, an upper computer and a force hammer. The invention has the characteristics of high efficiency and high accuracy in measuring the resonance frequency of the industrial robot.
Description
Technical Field
The invention relates to the technical field of robots, in particular to a measuring device and a measuring method for measuring the resonance frequency of an industrial robot, which are high in efficiency and accuracy.
Background
Industrial robot all can produce the vibration under transportation or operating condition, and when excitation source vibration frequency was close or equal with industrial robot's resonant frequency, industrial robot can produce violent vibration, seriously influences its working property, reduces production efficiency, consequently, need measure industrial robot's resonant frequency to make excitation source vibration frequency keep away industrial robot's resonant frequency, guarantee industrial robot's normal work.
In the prior art, a single-response-point method is usually adopted to measure the resonance frequency of the industrial robot, and the problems of large measurement error and low measurement precision exist.
Disclosure of Invention
The invention aims to overcome the defects of large measurement error and low measurement precision of the single-response-point method for measuring the resonance frequency of the industrial robot in the prior art, and provides a measuring device and a measuring method for measuring the resonance frequency of the industrial robot, which have high efficiency and high precision.
In order to achieve the purpose, the invention adopts the following technical scheme:
a measuring device for measuring the resonance frequency of an industrial robot comprises a base, N joints and N motors, wherein the N joints and the N motors are sequentially numbered from near to far away from the base and are respectively used for driving the corresponding joints to rotate, and N is more than or equal to 4; the device is characterized in that the measuring device comprises a tail end plate connected with the Nth joint, m three-way accelerometers, a multi-channel dynamic signal analyzer, an upper computer and a force hammer; 1 three-way accelerometer is respectively arranged in the middle of the outer surface of the tail end plate, and m-1 three-way accelerometers are respectively arranged on the (N-m + 2) th joint to the Nth joint, wherein m is less than or equal to N; the three-way accelerometer is electrically connected with the multi-channel dynamic signal analyzer, the multi-channel dynamic signal analyzer is electrically connected with the upper computer, and the multi-channel dynamic signal analyzer is electrically connected with the force sensor arranged on the peripheral surface of the force hammer.
Preferably, the joint comprises a cylinder with an opening at one end, and a bottom plate of the cylinder is fixedly connected with a rotating shaft of the corresponding motor; among the (N-m + 2) th joints to the (N) th joint, for the joint of which the outer end of the opening end of the cylinder is exposed out of the outer peripheral surface of the industrial robot, the three-way accelerometer is installed on the outer end surface of the opening end of the cylinder; of the N-m +2 th to N-th joints, for the joint in which the cylinder is located inside the outer peripheral surface of the industrial robot, a three-way accelerometer is mounted on the outer peripheral surface of the industrial robot near the outer end surface of the open end of the cylinder; a three-way accelerometer on the nth joint is mounted on the base plate of the cylinder.
Preferably, of the (N-m + 2) th to nth joints, for the joint of which the outer end of the opening end of the cylinder is exposed outside the outer peripheral surface of the industrial robot, two slide rails are arranged on the outer end surface of the opening end of the cylinder, the extending directions of the two slide rails are parallel to one diameter of the end surface of the opening end of the cylinder, and the two slide rails are respectively positioned on two sides of the diameter;
the two slide rails are provided with a plurality of groups of through holes which are arranged at intervals along the extending direction of the slide rails, and one group of through holes comprises two through holes which are respectively positioned on the opposite side surfaces of the two slide rails; the two slide rails are fixedly connected with the corresponding three-dimensional accelerometer through a clamp, the clamp comprises a base plate, a rectangular groove arranged on the upper surface of the base plate, a threaded hole arranged on the rectangular groove, and a front clamping plate and a rear clamping plate which are arranged on two sides of the threaded hole on the lower surface of the base plate; a rectangular lug is arranged on the lower surface of the base plate between the front clamping plate and the rear clamping plate, a vertical hole corresponding to the threaded hole is arranged on the upper surface of the rectangular lug, and threads are arranged on the inner side wall of the vertical hole; a back clearance is arranged between the back side face of the rectangular convex block and the back splint, a front clearance is arranged between the front side face of the rectangular convex block and the front splint, the back clearance and the front clearance are respectively matched and connected with the two guide rails, and a threaded rod arranged on the three-way accelerometer is matched and connected with the threaded hole and the vertical hole.
Preferably, two front elastic protrusions are arranged on the front side face of the rectangular bump, two rear elastic protrusions are arranged on the rear side face of the rectangular bump, the two front elastic protrusions are respectively matched and connected with 2 front through holes of the 2 groups of through holes, and the two rear elastic protrusions are respectively matched and connected with two rear through holes of the 2 groups of through holes.
The front elastic bulge, the rear elastic bulge and the through hole pair are arranged, so that the sliding block can move relative to the sliding rail, the three-way accelerometer can be arranged at different positions of the outer end face of the opening end of the articulated cylinder, the detected position is more variable, and the detection requirement is met.
Preferably, the device also comprises a moving mechanism for driving the power hammer to move, wherein the moving mechanism comprises a rear vertical plate, a horizontal supporting arm arranged on the upper part of the front surface of the rear vertical plate, a vertical supporting plate arranged on the front part of the lower surface of the horizontal supporting arm, and a cylinder arranged on the inner side of the joint of the vertical supporting plate and the horizontal supporting arm; the vertical support plate is provided with a strip-shaped opening, the right end of a telescopic rod of the air cylinder extends out of the front of the strip-shaped opening and is connected with the upper end of the lever, the middle part of the lever is rotatably connected with a support piece arranged on the edge of the strip-shaped opening, the lower end of the lever is hinged with the right end of the horizontal rod, the left end of the horizontal rod is connected with the force hammer, the lower end of the vertical support plate is provided with a horizontal plate, a transverse sliding groove is arranged on the upper surface of the horizontal plate, the lower side of the force hammer is connected with a guide rod, the guide rod is in sliding connection with the transverse sliding groove, and the distance between the support piece and the upper end of the lever is greater than the distance between the support piece and the lower end of the lever; the industrial robot is located between back riser and the vertical support plate, and the power hammer is located the drum periphery place ahead of the nth joint.
According to the moving mechanism, the telescopic rod of the cylinder of the moving mechanism drives the upper end of the lever to move back and forth, so that the power hammer is driven to move back and forth, when the power hammer approaches and hits the front side of the outer peripheral surface of the cylinder of the Nth joint, the force sensor on the power hammer detects an excitation signal, and each three-way accelerometer detects a response signal. The air cylinder of the moving mechanism can ensure that the amplitude of the forward and backward movement of the force hammer is the same during each test through controlling the stroke of the telescopic rod, so that the striking force of the force hammer is kept stable during each test.
A measuring method of a measuring device for measuring a resonant frequency of an industrial robot, comprising the steps of:
the upper computer performs Fourier transform on the response signal y (t) of each three-way accelerometer to obtain a frequency response function, maximum value points of a curve of the frequency response function are read from the frequency response function according to the sequence of frequency values from small to large, and the frequency corresponding to the read maximum value points is the resonance frequency of the industrial robot measured by each three-way accelerometer;
Preferably, step 3 comprises the steps of:
step 3-1, knowing the transfer function of the industrial robot with Z degree of freedom:
wherein b is the serial number of m three-way accelerometers, and b is more than or equal to 1 and less than or equal to m; k represents the kth excitation point, and k is more than or equal to 1; a. theb,k,iIdentifying the obtained residue according to the structure of the industrial robot; lambda [ alpha ]iBeing the pole of the ith order mode of the industrial robot,
is Ab,k,iIn the form of a dual of (a),
is λiω is the angular frequency of the transfer function, j is an imaginary number;
and 3-2, setting the error e (omega) of the transfer function as:
wherein the content of the first and second substances,
wherein Hb,k(ω) is a function frequency response prediction value of the industrial robot at ω,
is the average value, H ', of actual frequency response measured values of each joint of the industrial robot at omega'b,k,i1(ω) is the actual frequency response measurement at ω for each joint of the industrial robot; and the error of the transfer function is the comprehensive result of each joint error, namely:
wherein Hb,k,i1(ω) is the transfer function for each joint;
step 3-3, optimizing e (omega) by adopting a least square algorithm, and setting a function f (e (omega)) obtained after optimization as a weight function W (omega);
step 3-4, calculating f1，f2，…，fmAverage value of (2)
Step 3-5, calculating f1，f2，…，fmWeighted w of1，w2,...,wm:
And 3-6, calculating the resonance frequency f of the industrial robot by using the following formula:
the base of the industrial robot is arranged on the shock insulation base, so that the vibration of the industrial robot in the measuring process is reduced, the three-way accelerometer is connected to the multi-channel dynamic signal analyzer, the multi-channel dynamic signal analyzer realizes data exchange and communication with an upper computer through a USB port, and is used for processing and analyzing the vibration data of the industrial robot and obtaining the resonance frequency of the industrial robot, meanwhile, the multi-channel dynamic signal analyzer is connected with the force sensor, and the force hammer is used for knocking the Nth joint of the industrial robot, so that the vibration of the end plate and each joint is generated.
According to the invention, the resonance frequency of the industrial robot is obtained through efficient and accurate measurement and calculation, so that the vibration frequency of the excitation source can effectively avoid the resonance frequency of the industrial robot, the working performance of the industrial robot is improved, and the production efficiency and the service life of the industrial robot are improved.
Therefore, the invention has the following beneficial effects: the resonance frequency of the industrial robot can be obtained by efficient and accurate measurement and calculation, so that the resonance frequency of the industrial robot can be effectively avoided by the vibration frequency of the excitation source, and the working performance, the production efficiency and the service life of the industrial robot are improved.
Drawings
FIG. 1 is a side view of the displacement mechanism of the present invention;
FIG. 2 is a functional block diagram of the present invention;
FIG. 3 is a top view of the guide rail of the present invention;
FIG. 4 is a top view of the clamp of the present invention;
FIG. 5 is a bottom view of the clip of the present invention;
fig. 6 is a schematic structural view of an industrial robot in an embodiment of the invention;
FIG. 7 is a graph comparing the results of the measurements of the present invention and the single point method.
Detailed Description
The invention is further described with reference to the following figures and detailed description.
The embodiment shown in fig. 6 is a measuring device for measuring the resonant frequency of an industrial robot, and the industrial robot 10 comprises a base 11, 6 joints 12 and 6 motors 13, wherein the joints 12 and the motors 13 are sequentially numbered from near to far from the base and are respectively used for driving the corresponding joints to rotate; the measuring device comprises a circular end plate 14 connected with the 6 th joint, as shown in figure 2, 5 three-way accelerometers 1, a multi-channel dynamic signal analyzer 2, an upper computer 3 and a force hammer 4; 1 three-way accelerometer is arranged in the middle of the outer surface of the end plate, and the other 4 three-way accelerometers are respectively arranged on the 3 rd joint to the 6 th joint; the three-way accelerometer is electrically connected with a multi-channel dynamic signal analyzer, the multi-channel dynamic signal analyzer is electrically connected with an upper computer, and the multi-channel dynamic signal analyzer is electrically connected with a force sensor 401 arranged on the peripheral surface of the force hammer.
As can be seen from fig. 6, the base is connected with the 1 st joint through the first motor, the 1 st joint is connected with the second motor through the first connecting rod, the second motor is connected with the third joint through the second connecting rod, the third joint is connected with the fourth motor through the third connecting rod, the fourth motor is connected with the fourth joint, the fourth joint is connected with the fifth motor through the fourth connecting rod, the fifth motor is connected with the fifth joint through the belt pulley and the belt, the fifth joint is connected with the sixth motor, and the sixth motor is connected with the sixth joint;
as shown in fig. 6, the joint includes a cylinder 121 with an opening at one end, and a bottom plate of the cylinder is fixedly connected with a rotating shaft of a corresponding motor; the outer ends of the opening ends of the cylinders of the 3 rd joint and the 6 th joint are exposed out of the outer peripheral surface of the industrial robot, and the three-way accelerometer is installed on the outer end surface of the opening end of the cylinder; the cylinder of the 4 th joint is positioned in the outer peripheral surface of the industrial robot, and the three-way accelerometer is arranged on the outer peripheral surface of the industrial robot close to the outer end surface of the opening end of the cylinder; the three-way accelerometer on the 6 th joint is mounted on the bottom plate of the cylinder.
As shown in fig. 3, 4 and 5, two sliding rails 2 are arranged on the outer end faces of the opening ends of the cylinders of the 3 rd joint and the 6 th joint, the extending directions of the two sliding rails are both parallel to one diameter of the end face of the opening end of the cylinder, and the two sliding rails are respectively positioned on two sides of the diameter;
the two slide rails are provided with 5 groups of through holes which are arranged at intervals along the extension direction of the slide rails, and one group of through holes comprises two through holes which are respectively positioned on the opposite side surfaces of the two slide rails; the two slide rails are fixedly connected with the corresponding three-way accelerometer through a clamp 3, the clamp comprises a base plate 31, a rectangular groove 32 arranged on the upper surface of the base plate, a threaded hole 33 arranged on the rectangular groove, and a front clamping plate 34 and a rear clamping plate 35 which are arranged on two sides of the threaded hole on the lower surface of the base plate; a rectangular bump 36 is arranged on the lower surface of the base plate between the front clamping plate and the rear clamping plate, a vertical hole corresponding to the threaded hole is arranged on the upper surface of the rectangular bump, and threads are arranged on the inner side wall of the vertical hole; a back clearance is arranged between the back side face of the rectangular convex block and the back splint, a front clearance is arranged between the front side face of the rectangular convex block and the front splint, the back clearance and the front clearance are respectively matched and connected with the two guide rails, and a threaded rod arranged on the three-way accelerometer is matched and connected with the threaded hole and the vertical hole.
The front side face of the rectangular bump is provided with two front elastic bulges, the back side face of the rectangular bump is provided with two back elastic bulges, the two front elastic bulges are respectively matched and connected with 2 front through holes of the 2 groups of through holes, and the two back elastic bulges are respectively matched and connected with two back through holes of the 2 groups of through holes.
As shown in fig. 1, the device further comprises a moving mechanism for driving the power hammer to move, wherein the moving mechanism comprises a rear vertical plate 40, a horizontal supporting arm 41 arranged on the upper part of the front surface of the rear vertical plate, a vertical supporting plate 42 arranged on the front part of the lower surface of the horizontal supporting arm, and a cylinder 43 arranged on the inner side of the joint of the vertical supporting plate and the horizontal supporting arm; the vertical support plate is provided with a strip-shaped opening, the right end of a telescopic rod of the air cylinder extends out of the front of the strip-shaped opening and is connected with the upper end of a lever 44, the middle part of the lever is rotatably connected with a support piece 45 arranged on the edge of the strip-shaped opening, the lower end of the lever is hinged with the right end of a horizontal rod 46, the left end of the horizontal rod is connected with a force hammer, the lower end of the vertical support plate is provided with a horizontal plate 47, the upper surface of the horizontal plate is provided with a transverse sliding groove, the lower side of the force hammer is connected with a guide rod 48, the guide rod is in sliding connection with the transverse sliding groove, and the distance between the support piece and the upper end of the lever is larger than the distance between the support piece and the lower end of the lever; the industrial robot is located between back riser and the vertical support plate, and the power hammer is located 6 th articular drum periphery place ahead.
A measuring method of a measuring device for measuring a resonant frequency of an industrial robot, comprising the steps of:
the upper computer performs Fourier transform on the response signal y (t) of each three-way accelerometer to obtain a frequency response function, reads 1-order maximum value point of a curve of the frequency response function according to the sequence of frequency values from small to large, and takes the 1-order maximum value point as the resonance frequency of the industrial robot measured by each three-way accelerometer;
step 3-1, the transfer function of the known 6-degree-of-freedom industrial robot is:
wherein b is the serial number of 5 three-way accelerometers, and b is more than or equal to 1 and less than or equal to 5; k represents the k excitation point, the front side of the cylinder of the 6 th joint is knocked by a force hammer, the force hammer only knocks at the position, the invention only has one excitation point, and k is 1; if the hammer can strike other positions, a plurality of excitation points exist;
Ab,k,irepresenting the residue obtained by the structure identification of the industrial robot; lambda [ alpha ]iBeing the pole of the ith order mode of the industrial robot,
is Ab,k,iIn the form of a dual of (a),
is λiThe dual form of (a), ω is the angular frequency of the transfer function;
and 3-2, setting the error e (omega) of the transfer function as:
wherein the content of the first and second substances,
wherein Hb,k(ω) is a function frequency response prediction value of the industrial robot at ω,
is the average value, H ', of actual frequency response measured values of each joint of the industrial robot at omega'b,k,i1(ω) is the actual frequency response measurement at ω for each joint of the industrial robot; and the error of the transfer function is the comprehensive result of each joint error, namely:
wherein Hb,k,i1(ω) is the transfer function for each joint;
step 3-3, optimizing e (omega) by adopting a least square algorithm, and setting a function f (e (omega)) obtained after optimization as a weight function W (omega);
step 3-4, calculating f1，f2，…，fmAverage value of (2)
Step 3-5, calculating f1，f2，…，fmWeighted w of1，w2,...,wm:
And 3-6, calculating the resonance frequency f of the industrial robot by using the following formula:
the purpose of simultaneously measuring a plurality of joints is to ensure the accuracy of the measurement result, and 2 three-way accelerometers can be added to the 1 st joint and the 2 nd joint to form 7 pieces of acceleration data, and then the resonance frequency of the industrial robot is obtained by a data average weighting method.
And (3) analyzing an experimental effect:
the method comprises the steps of measuring the resonance frequency of the six-axis industrial robot S5A901 by using a frequency sweep method, and determining that the 1 st order resonance frequency is 10.2HZ, wherein the frequency sweep method has the defects of long measurement time, more required equipment, complex operation and high measurement cost.
Meanwhile, the resonance frequency of the six-axis industrial robot S5A901 is measured by adopting the method and the frequency sweep method, and the average value is obtained by measuring for 5 times in all the methods.
The three-direction accelerometer is an MEMS zero-frequency sensor with the model of BWJ38511, the sensitivity of 2000mV/g, the measurement range of 2g, the frequency range (+/-3 dB) of 0-200Hz and the appearance of 23mm multiplied by 20 mm.
The model of the dynamic signal analyzer is as follows: MI-7008, class A;
the impact hammer has the following model: 086D05, 0.23 mV/N; the single-response-point method is simply referred to as a single-point method.
The results of the two tests are shown in the following table:
it can be seen from the above figure that the error of the resonance frequency measured by the multipoint method is only 1.3%, while the error measured by the single-point method reaches 6.9%, the accuracy of the multipoint measurement is obviously improved compared with the single-point method, and the measurement result of the resonance frequency measured by the multipoint measurement is more accurate than that of the measurement method of only measuring 1 point.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (7)
1. A measuring device for measuring the resonance frequency of an industrial robot is disclosed, wherein the industrial robot (10) comprises a base (11), N joints (12) and N motors (13) which are sequentially numbered from near to far away from the base and are respectively used for driving the corresponding joints to rotate, and N is more than or equal to 4; the device is characterized in that the measuring device comprises a tail end plate (14) connected with an Nth joint, m three-way accelerometers (1), a multi-channel dynamic signal analyzer (2), an upper computer (3) and a force hammer (4); 1 three-way accelerometer is respectively arranged in the middle of the outer surface of the tail end plate, and m-1 three-way accelerometers are respectively arranged on the (N-m + 2) th joint to the Nth joint, wherein m is less than or equal to N; the three-way accelerometer is electrically connected with a multi-channel dynamic signal analyzer, the multi-channel dynamic signal analyzer is electrically connected with an upper computer, and the multi-channel dynamic signal analyzer is electrically connected with a force sensor (401) arranged on the peripheral surface of the force hammer.
2. A measuring device for measuring the resonance frequency of an industrial robot according to claim 1, characterized in that the joint comprises a cylinder (121) with an open end, the bottom plate of which is fixedly connected to the rotating shaft of the corresponding motor; among the (N-m + 2) th joints to the (N) th joint, for the joint of which the outer end of the opening end of the cylinder is exposed out of the outer peripheral surface of the industrial robot, the three-way accelerometer is installed on the outer end surface of the opening end of the cylinder; of the N-m +2 th to N-th joints, for the joint in which the cylinder is located inside the outer peripheral surface of the industrial robot, a three-way accelerometer is mounted on the outer peripheral surface of the industrial robot near the outer end surface of the open end of the cylinder; a three-way accelerometer on the nth joint is mounted on the base plate of the cylinder.
3. The measuring device for measuring the resonance frequency of an industrial robot according to claim 2, wherein of the N-m +2 th to nth joints, two slide rails (2) are provided on the outer end surface of the open end of the cylinder with respect to the joint of which the outer end of the open end is exposed outside the outer peripheral surface of the industrial robot, the two slide rails each extending in a direction parallel to one diameter of the end surface of the open end of the cylinder, the two slide rails being located on both sides of the diameter;
the two slide rails are provided with a plurality of groups of through holes which are arranged at intervals along the extending direction of the slide rails, and one group of through holes comprises two through holes which are respectively positioned on the opposite side surfaces of the two slide rails; the two slide rails are fixedly connected with the corresponding three-way accelerometer through a clamp (3), the clamp comprises a base plate (31), a rectangular groove (32) arranged on the upper surface of the base plate, a threaded hole (33) arranged on the rectangular groove, and a front clamping plate (34) and a rear clamping plate (35) which are arranged on two sides of the threaded hole on the lower surface of the base plate; a rectangular lug (36) is arranged on the lower surface of the base plate between the front clamping plate and the rear clamping plate, a vertical hole corresponding to the threaded hole is arranged on the upper surface of the rectangular lug, and a thread is arranged on the inner side wall of the vertical hole; a back clearance is arranged between the back side face of the rectangular convex block and the back splint, a front clearance is arranged between the front side face of the rectangular convex block and the front splint, the back clearance and the front clearance are respectively matched and connected with the two guide rails, and a threaded rod arranged on the three-way accelerometer is matched and connected with the threaded hole and the vertical hole.
4. A measuring apparatus for measuring the resonant frequency of an industrial robot according to claim 3, wherein two front elastic protrusions are provided on the front side of the rectangular protrusion, two rear elastic protrusions are provided on the rear side of the rectangular protrusion, the two front elastic protrusions are respectively connected with 2 front through holes of the 2 sets of through holes, and the two rear elastic protrusions are respectively connected with two rear through holes of the 2 sets of through holes.
5. The measuring device for measuring the resonance frequency of an industrial robot according to claim 2, further comprising a moving mechanism for moving the power hammer, wherein the moving mechanism comprises a rear vertical plate (40), a horizontal supporting arm (41) arranged on the upper part of the front surface of the rear vertical plate, a vertical supporting plate (42) arranged on the front part of the lower surface of the horizontal supporting arm, and a cylinder (43) arranged on the inner side of the joint of the vertical supporting plate and the horizontal supporting arm; the vertical support plate is provided with a strip-shaped opening, the right end of a telescopic rod of the air cylinder extends out of the front of the strip-shaped opening and is connected with the upper end of a lever (44), the middle part of the lever is rotatably connected with a support piece (45) arranged on the edge of the strip-shaped opening, the lower end of the lever is hinged with the right end of a horizontal rod (46), the left end of the horizontal rod is connected with a force hammer, the lower end of the vertical support plate is provided with a horizontal plate (47), the upper surface of the horizontal plate is provided with a transverse chute, the lower side of the force hammer is connected with a guide rod (48), the guide rod is in sliding connection with the transverse chute, and the distance between the support piece and the upper end of the lever is larger than the distance between the support piece and the lower end of the lever; the industrial robot is located between back riser and the vertical support plate, and the power hammer is located the drum periphery place ahead of the nth joint.
6. A measuring method of a measuring device for measuring a resonant frequency of an industrial robot according to claim 1, characterized by comprising the steps of:
step 1, enabling the X, Y, Z direction of each three-way accelerometer to coincide with the base coordinate system of the industrial robot, and installing a vibration isolation base between the base of the industrial robot and the ground; electrifying each motor to work and driving each joint to rotate;
step 2, knocking the Nth joint by using a force hammer to provide a transient impact force for the industrial robot, reading an input excitation signal delta (t) detected by a force sensor by a dynamic signal analyzer, and reading a response signal y (t) of each three-way accelerometer by the dynamic signal analyzer, wherein t is time;
the upper computer performs Fourier transform on the response signal y (t) of each three-way accelerometer to obtain a frequency response function, maximum value points of a curve of the frequency response function are read from the frequency response function according to the sequence of frequency values from small to large, and the frequency corresponding to the read maximum value points is the resonance frequency of the industrial robot measured by each three-way accelerometer;
step 3, setting the resonance frequencies measured by the m three-way accelerometers to be f respectively1、f2、…、fmUsing f1,f2,…,fmCalculating the resonance frequency f of the industrial robot.
7. The measuring method of a measuring device for measuring a resonant frequency of an industrial robot according to claim 6, characterized in that step 3 comprises the steps of:
step 3-1, knowing the transfer function of the industrial robot with Z degree of freedom:
wherein b is the serial number of m three-way accelerometers, and b is more than or equal to 1 and less than or equal to m; k represents the kth excitation point, and k is more than or equal to 1; a. theb,k,iRepresenting the residue obtained by the structure identification of the industrial robot; lambda [ alpha ]iBeing the pole of the ith order mode of the industrial robot,
is Ab,k,iIn the form of a dual of (a),
is λiω is the angular frequency of the transfer function, j is an imaginary number;
and 3-2, setting the error e (omega) of the transfer function as:
wherein the content of the first and second substances,
wherein Hb,k(ω) is a function frequency response prediction value of the industrial robot at ω,
is the average value, H ', of actual frequency response measured values of each joint of the industrial robot at omega'b,k,i1(ω) is the actual frequency response measurement at ω for each joint of the industrial robot; and the error of the transfer function is the comprehensive result of each joint error, namely:
wherein Hb,k,i1(ω) is the transfer function for each joint;
step 3-3, optimizing e (omega) by adopting a least square algorithm, and setting a function f (e (omega)) obtained after optimization as a weight function W (omega);
step 3-4, calculating f1，f2，…，fmAverage value of (2)
Step 3-5, calculating f1，f2，…，fmWeighted w of1，w2,...,wm:
And 3-6, calculating the resonance frequency f of the industrial robot by using the following formula:
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