CN103056759A - Robot grinding system based on feedback of sensor - Google Patents

Abstract

The invention discloses and relates to a robot grinding system based on feedback of a sensor. The robot grinding system based on the feedback of the sensor is capable of detecting an contour of a workpiece and regulating grinding tracks in real time and comprises a robot (1), a workpiece contour detection unit (2), an electro-spindle unit (3), a grinding wheel wear detection unit (4), a grinding force detection unit (5) and a system control host (6). The robot grinding system based on the feedback of the sensor achieves automatic grinding on workpiece surface by detecting the grinding force between a grinding wheel and a workpiece, the three-dimensional measuring data of the outline of the workpiece and wear degree of the grinding wheel and controlling feed speed and rotating speed of the grinding wheel through a control algorithm.

Description

A kind of robot grinding system based on sensor feedback

Technical field

The present invention relates to a kind of robot grinding system for grinding work piece, belong to the robot grinding manufacture field.

Background technology

The range of application of grinding is widely used, and the quality of grinding often determines the final mass of product.Along with the extensive use of the materials such as special mild steel, aluminium alloy or nickel alloy in the fields such as Aero-Space, national defence, electric power, boats and ships, such as the manufacturing of a large amount of employing such as aero-engine, large-size steam turbine, gas turbine, marine propeller, blade of wind-driven generator above-mentioned material, challenging requirement has been proposed the grinding-polishing technology.

Traditional large-scale workpiece grinding mainly contains several modes such as artificial grinding, special purpose machine tool grinding and Digit Control Machine Tool grinding.The mode workload of artificial grinding is large, efficient is low, and the quality of workpiece processing can not be guaranteed; The special purpose machine tool versatility is bad, is mainly used in the production process of parts in enormous quantities; The Digit Control Machine Tool cost is higher.All do not have the process control for stock removal in these grinding process, grinding process mainly improves the roughness of workpiece.In addition, manually homogeneity and the quality thereof of inefficiency, grinding and the polishing of grinding-polishing can not ensure, the environment such as dust in grinding place are abominable, and are serious to workman's health hazard.Therefore, development automatic grinding polishing machine robot system has important application value.

Compare with Digit Control Machine Tool, the grinding robot has the higher flexibility workpiece of different size and unlike material (can the grinding different size), better versatility and adaptability (by researching and developing new software module, can make robot in the complex work environment, finish efficiently the grinding task).The robot grinding technology becomes present assurance grinding quality, improves one of main development direction of grinding efficiency.

Publication number is the Chinese invention patent (a kind of grinding process position-stance error automatic adjusting method and system) of CN101462255A, by online position and the attitude information that detects in real time workpiece of automatic detection device, feed back to control system analysis, determine the Position and orientation parameters of workpiece, then adjust position and the attitude of workpiece by executing agency.Publication number is that the patent of invention (based on the robot grinding method of robot learning) of CN101738981A is at the stages of abrasive band work, workpiece to unlike material carries out grinding, obtain the contact force of workpiece and emery wheel, the curvature of workpiece grinding face and stock removal, process velocity.Utilize initial data, adopt the method for machine learning, carry out the Dynamic Modeling of grinding system, and according to the measurement data of current working condition, set up the current robot self-adapting power and learn model, optimize the grinding track of robot.Publication number is that the patent of invention (a kind of method for shaping, grinding and processing abrasive band based on standard workpiece) of CN101462248 adopts the mode of sbrasive belt grinding to realize that the automation of complex profile workpiece repaiies the type grinding, the method generates each grinding parameter automatically according to the stock removal of each point of input, then according to these parameters, generate actual machining path; Grinding unit adopts belt grinding machine, and it can accept the instruction of robot, finishes the type of the repairing grinding of workpiece.

Above-mentioned method mainly adopts off-line to set up grinding parameter, generates the robot grinding track, and control is finished according to the grinding track and repaiied the type grinding.In grinding process, the abrasion of grinding wheel that causes of friction, the workpiece position errors that vibration causes etc. all can produce the grinding deviation of robot.If the grinding track according to off-line planning is repaiied the type grinding, probably can't remove the workpiece of setting and repair the type amount.

Summary of the invention

The technical problem that (one) will solve

Technical problem to be solved by this invention is that existing robot grinding system can not revise and causes reaching the problem that predetermined workpiece is repaiied the type amount the workpiece position error in the grinding process

(2) technical scheme

Ask for solving above-mentioned technology, the present invention proposes a kind of robot grinding system, be used for workpiece is carried out grinding, comprise system's main control system, robot, be installed on robot end's spindle motor unit and the emery wheel that is installed on the end of spindle motor unit, described system main control system is by the rotation to emery wheel of control spindle motor unit, and the control end is finished grinding process to workpiece to the translation of emery wheel, described robot grinding system also comprises the workpiece profile detecting unit, it produces the workpiece profile data and flows to system's main control system for detection of the profile of workpiece; Described system main control system produces rotary speed data and feed speed data according to these workpiece profile data, respectively it is inputed to spindle motor unit and robot, to control described emery wheel for the grinding process of workpiece.

(3) beneficial effect

Robot grinding of the present invention system regulates velocity of rotation and the feed speed of emery wheel by employing power sensor information FEEDBACK CONTROL robot and electric main shaft, can grinding workpiece dissimilar, complex profile.

Description of drawings

Fig. 1 is the structural representation of an embodiment of the robot grinding system based on force feedback of the present invention;

Fig. 2 is arbitrfary point P on the reconstruct surface of the work of the present invention _iThree-dimensional coordinate (x _i, y _i, z _i) schematic diagram;

Fig. 3 is the schematic diagram of grinding angle α;

Fig. 4 is of the present invention by m experimental calculation grinding COEFFICIENT K _tAnd K _nFlow chart;

Fig. 5 is the control structure figure of the robot grinding system of systems main control system 6 based on force feedback of the present invention;

Figure 6 shows that the operational flowchart of grinding trajectory planning module 61 of the present invention;

Figure 7 shows that the operational flowchart of control of grinding force module 62 of the present invention.

The specific embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in further detail.

Fig. 1 is the structural representation of an embodiment of the robot grinding system based on force feedback of the present invention.As shown in Figure 1, this system is used for workpiece 7 is carried out grinding, and system comprises robot 1, workpiece profile detecting unit 2, spindle motor unit 3, abrasion of grinding wheel detecting unit 4, grinding force detecting unit 5 and system's main control system 6.

Wherein, robot 1 is used for installing spindle motor unit 3, and controls spindle motor unit 3 and carry out translation, to arrive the precalculated position that workpiece 7 is carried out grinding.Robot 1 can adopt existing robot, for example the IRB4400 of robot of ABB AB.

Workpiece profile detecting unit 2 produces the workpiece profile data and flows to system's main control system 6 for detection of the profile of workpiece.The present invention is preferably and adopts binocular camera shooting head (two cameras) to detect the reference position of surface of the work, and utilizes the two-dimentional workpiece image of two camera Real-time Collections, adopts three-dimensional reconstruction method to make up three-dimensional workpiece profile data.As shown in Figure 1, workpiece profile detecting unit 2 comprises two cameras 21,22, has consisted of the binocular camera shooting head.

Spindle motor unit 3 comprises electric main shaft 31, emery wheel 32, electric spindle controller 33 and electric spindle driver 34; Electricity main shaft 31 is installed on the end of worker robot 1, and emery wheel 32 is installed on the end of electric main shaft 31.Electricity spindle controller 33 is used for receiving the rotary speed data that is sent by system's main control system 6, is converted into to be delivered to electric spindle driver after driving signal; Electricity spindle driver 34 is controlled electric main shaft 31 according to this driving signal and is reached predetermined velocity of rotation.Thus, spindle motor unit 3 can drive 32 pairs of workpiece of emery wheel 7 and carries out grinding under the control of system's main control system 6.Electricity main shaft 31 can adopt HCS180-24000/41 type electricity main shaft.Electricity spindle controller 33 can adopt the LNCT520i spindle controller, and electric spindle driver 34 can adopt Ai Mo to give birth to the EV6000 frequency converter.

Abrasion of grinding wheel detecting unit 4 obtains the abrasion of grinding wheel level data and is transferred to system's main control system 6 for detection of the degree of wear of emery wheel 32.Abrasion of grinding wheel detecting unit 4 can adopt laser vision sensor 41.

Grinding force detecting unit 5 produces the grinding force data and flows to system's main control system 6 for detection of the grinding force between workpiece 7 and the emery wheel 32.Grinding force detecting unit 5 comprises six-dimension force sensor 51 and data acquisition module 52.Six-dimension force sensor 41 is installed in the end of robot 1, for detection of the grinding force between workpiece in the grinding process 7 and the emery wheel 32.Data acquisition module 52 is used for gathering tangential component and the normal component of grinding force, and generation grinding force data also are input in system's main control system 6.

System's main control system 6 is used for the rotation of 3 pairs of emery wheels 32 of control spindle motor unit and robot 1 end grinding process to workpiece 7 is finished in the translation of emery wheel 32.Specifically, system's main control system 6 produces rotary speed data and feed speed data according to workpiece profile data, abrasion of grinding wheel level data and grinding force data, respectively it is inputed to electric spindle controller 33 and the robot 1 of spindle motor unit 3, with the grinding process of control emery wheel 32 for workpiece 7.

Specifically, system's main control system comprises three inputs and two outputs.As shown in Figure 1, input 641 connects the output of sand workpiece profile detecting unit 2; Input 642 connects the output of abrasion of grinding wheel detecting unit 4; Input 643 connects the output of grinding force detecting unit 5.Output 651 connects the input of robot 1; Output 653 connects the input of spindle motor unit 3.The output 651 of the input connected system main control system 6 of robot 1 is used for the feed speed data that receiving system main control system 6 sends, thereby drives the emery wheel translation.

In addition, system's main control system 6 comprises grinding trajectory planning module 61, Robot calibration module 62 and control of grinding force module 63.The function of modules and operation will describe in detail hereinafter.

The reconstruct workpiece profile

The present invention is preferably and adopts the binocular camera shooting head as workpiece profile detecting unit 3, with the 3 d measurement data of three-dimensionalreconstruction workpiece profile as previously mentioned.The below specifies the method for the coordinate of arbitrfary point Pi on the three-dimensionalreconstruction surface of the work:

Fig. 2 is arbitrfary point P on the reconstruct surface of the work _iThree-dimensional coordinate (x _i, y _i, z _i) schematic diagram.As shown in Figure 2, the present invention adopts the method for different surface beeline to find the solution P _iCoordinate.Arbitrfary point P on the three-dimensionalreconstruction surface of the work _iThe job step of coordinate as follows:

Steps A 1: the two-dimensional pixel coordinate (u that sets up camera 21 ^L, v ^L) and three dimensional space coordinate (x ^L, y ^L, z ^L) between relation, shown in (1):

$\left[\begin{array}{c}{\mathrm{su}}^L\\ {\mathrm{sv}}^L\\ s^L\end{array}\right]=\left[\begin{array}{cccc}{m}_{11}^L& m_{12}^L& m_{13}^L& m_{14}^L\\ m_{21}^L& m_{22}^L& m_{23}^L& m_{24}^L\\ m_{31}^L& m_{32}^L& m_{33}^L& m_{34}^L\end{array}\right]\left[\begin{array}{c}x\\ y\\ z\\ 1\end{array}\right]---\left(1\right)$

Parameter m in the formula (1) _Ij(i=1,2,3; J=1,2,3,4) in the camera calibration process, can obtain, s is proportionality coefficient.

Steps A 2: the two-dimensional pixel coordinate (u that sets up camera 22 ^R, v ^R) and three dimensional space coordinate (x ^R, y ^R, z ^R) between relation, shown in (2):

$\left[\begin{array}{c}{\mathrm{su}}^R\\ {\mathrm{sv}}^R\\ s^R\end{array}\right]=\left[\begin{array}{cccc}{m}_{11}^R& m_{12}^R& m_{13}^R& m_{14}^R\\ m_{21}^R& m_{22}^R& m_{23}^R& m_{24}^R\\ m_{31}^R& m_{32}^R& m_{33}^R& m_{34}^R\end{array}\right]\left[\begin{array}{c}x\\ y\\ z\\ 1\end{array}\right]---\left(2\right)$

Steps A 3: camera 21 and 22 is collection point P simultaneously _iImage.In the image of camera 21 and in the image of camera 22, identify respectively and calculate a P _iThe image coordinate in two width of cloth images: the image coordinate at camera 21 is (u _i ^R, v _i ^R), be (u in the image coordinate of camera 22 _i ^L, v _i ^L).

Steps A 4: with coordinate [(u _i ^R, v _i ^R), (u _i ^L, v _i ^L)] in substitution formula (1) and the formula (2), elimination factor s obtains about a P _iCoordinate (x _i, y _i, z _i) equation.This equation of finding the solution is suc as formula shown in (3):

$\left\{\begin{array}{c}(u_i^L{m}_{31}^L-m_{11}^L)x_i+(u_i^L{m}_{32}^L-m_{12}^L)y_i+(u_i^L{m}_{33}^L-m_{13}^L)z_i=m_{14}^L-u_i^L{m}_{34}^L\\ (v_i^L{m}_{31}^L-m_{21}^L)x_i+(v_i^L{m}_{32}^L-m_{22}^L)y_i+(v_i^L{m}_{33}^L-m_{23}^L)z_i=m_{24}^L-v_i^L{m}_{34}^L\\ (u_i^R{m}_{31}^R-m_{11}^R)x_i+(u_i^R{m}_{32}^R-m_{12}^R)y_i+(u_i^R{m}_{33}^R-m_{13}^R)z_i=m_{14}^R-u_i^R{m}_{34}^R\\ (v_i^R{m}_{31}^R-m_{21}^R)x_i+(v_i^R{m}_{32}^R-m_{22}^R)y_i+(v_i^R{m}_{33}^R-m_{23}^R)z_i=m_{24}^R-v_i^R{m}_{34}^R\end{array}\right.---\left(3\right)$

Steps A 5: with top formula simultaneous solution equation group, obtain a P _iThree-dimensional coordinate (x _i, y _i, z _i).In order to reduce the error of finding the solution, utilize least square method to find the solution transfiniting of top simultaneous and decide the homogeneous equation group, obtain a little 23, namely put P _iThree-dimensional coordinate (x _i, y _i, z _i).

Under ideal model, the defined straight line 211 of formula (3) and straight line 221 meet at 1: 23.If, when camera 21 and 22 model are not complete perspective model, and there is noise during imaging, straight line 211 and straight line 221 are different surface beelines, thereby can not meet at a bit.Thereby we also can use the mid point 24 of different surface beeline common vertical line to approach P _i

Detect the abrasion of grinding wheel degree

As previously mentioned, abrasion of grinding wheel detecting unit 3 adopts laser vision sensor to detect the abrasion of grinding wheel degree.In grinding process, every the set time, utilize the degree of wear of abrasion of grinding wheel detecting unit 3 detection emery wheels 32, make up the real-time characteristic profile of wheel face.

Adopt laser vision sensor to detect the abrasion of grinding wheel degree, at first utilize laser sensor to detect in real time the surface of emery wheel, by three-dimensional reconstruction method, the feature of real-time reconstruction wheel face.The real-time characteristic profile of rebuilding and the feature contour of presetting are compared, calculate the wear extent of emery wheel 32, produce the abrasion of grinding wheel level data.Laser vision sensor comprises binocular camera shooting head and line structure light source.Adopt the line-structured light triangulation to rebuild the real-time characteristic profile of wheel face, key step comprises:

Step B1: shine testee with line-structured light.When the reference stripe of structured light projected the testee surface, because body surface is uneven, distortion had occured in striped, and this distortion has comprised the three-dimensional information of object surface shape.

Step B2: taken by the subject image of the light-struck different parts of structure by the binocular camera shooting head.According to the Mathematical Modeling of corresponding relation between distortion striped and the object surface shape, the shape of stripes information after the distortion is inferred the three-dimensional information of object surface shape.

Detect grinding force

Grinding force detecting unit 5 is by being installed in the six-dimension force sensor 41 of robot 1 end, and the grinding force in the detection grinding process between workpiece 7 and the emery wheel 32 obtains the grinding force data.By detecting the tangential component F of the grinding force that obtains _tWith normal component F _n, system's main control system 6 is by rotation and the translation of control spindle motor unit 3 and industrial machine 1, and velocity of rotation and the feed speed of regulating emery wheel 32 are to remove the unnecessary part on workpiece 7 surfaces by grinding process.The tangential component F of the grinding force of grinding force _tWith normal component F _nRemove the relationship between quantities as shown in the formula expression with the velocity of rotation of emery wheel, feed speed and grinding:

The tangential grinding force of unit width is on the surface of the work:

$F_t=K_t\frac{V_W}{V_C}\left(\frac{1}{2}{\sin }^2\left(\mathrm{\α}\right)\right)---\left(1\right)$

The normal grinding force of unit width is on the surface of the work:

$F_n=K_n\frac{V_W}{V_C}\left(\frac{1}{2}{\sin }^2\left(\mathrm{\α}\right)\right)---\left(2\right)$

In the formula, V _CThe velocity of rotation of emery wheel, V _WIt is the feed speed of emery wheel; K _tAnd K _nBe the grinding coefficient, can calculate by experiment; α is the grinding angle that represents grinding removal amount SG.Be illustrated in figure 3 as the schematic diagram of grinding angle α.

Fig. 4 is for passing through m experimental calculation grinding COEFFICIENT K _tAnd K _nStep:

In 1: the i time experiment of steps A, the velocity of rotation of system's main control system 6 control emery wheels is V _Ci, feed speed is V _Wi, grinding force detecting unit 5 is measured the tangential component F of grinding force by six-dimension force sensor 41 _TiWith normal component F _Ni

Steps A 2: measure grinding removal amount SG by workpiece profile detecting unit 2 _i

Steps A 3: among repeating step A1 and the A2, finish m experiment, obtain training data set { (V _C1, V _W1, F _T1, F _N1, α ₁) ..., (V _Cm, V _Wm, F _Tm, F _Nm, α _m).

Steps A 4: based on m group training data, calculate optimum grinding COEFFICIENT K _tAnd K _n, computing formula is:

$K_t=\frac{1}{m}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}{F}_{\mathrm{ti}}\frac{{2V}_{\mathrm{Ci}}}{V_{\mathrm{Wi}}{\sin }^2\left({\mathrm{\α}}_i\right)}$

$K_n=\frac{1}{m}\underset{i=1}{\overset{m}{\mathrm{\Σ}}}{F}_{\mathrm{ni}}\frac{{2V}_{\mathrm{Ci}}}{V_{\mathrm{Wi}}{\sin }^2\left({\mathrm{\α}}_i\right)}$

System's control

Be illustrated in figure 5 as the control structure figure of system's main control system 6.As shown in Figure 5, system's main control system comprises grinding trajectory planning module 61, Robot calibration module 62 and control of grinding force module 63.Wherein, grinding trajectory planning module 61 is used for obtaining the grinding track of surface of the work according to the workpiece profile data of measuring in real time and the design data of workpiece profile, then plans the grinding motion track; Robot calibration module 62 is used for setting up the coordinate transform relation between robot coordinate system and the workpiece coordinate system, and the grinding motion track is converted to the end movement track of robot; Control of grinding force module 63 is used for according to described grinding force data, abrasion of grinding wheel data, workpiece profile data and location of workpiece data, calculate feed speed and the velocity of rotation of emery wheel, and with the velocity of rotation transfer of data to the described spindle motor unit (3), described feed speed is transferred in the robot (1).

Be illustrated in figure 7 as the algorithm flow of grinding trajectory planning module 61:

Step D1: detect data acquisition system { SR from workpiece profile detecting unit 2 input workpiece profiles _i(i=1,2 ..., n; N is the quantity of data).

Step D2: in advance storage workpiece profile design data set { SI in system's main control system 6 _i(i=1,2 ..., n; N is the quantity of data).

Step D3:{SR _iAnd { SI _iData carry out man-to-man comparison, difference is exactly the removal amount set { SG of surface of the work _i(i=1,2 ..., n; N is the quantity of data).

Step D4: according to removal amount set { SG _iAnd the best grinding force of emery wheel interval, calculate back and forth back and forth grinding number of times t, and j (the inferior removal amount set { SG of 1≤j≤t) _iJ.T is for satisfying t _Min≤ t≤t _MaxAn integer, wherein

$t_{\min }=\mathrm{<figure-callout\; id="2"\; label="arcsin"\; filenames="HDA00002637027500011.png"\; state="\{\{state\}\}">arcsin</figure-callout>}\sqrt{2\&CenterDot;\frac{\min \left(F_t\right)\min \left(V_C\right)}{K_t\max \left(V_W\right)}}$

$t_{\max }=\mathrm{<figure-callout\; id="2"\; label="arcsin"\; filenames="HDA00002637027500011.png"\; state="\{\{state\}\}">arcsin</figure-callout>}\sqrt{2\&CenterDot;\frac{\max \left(F_t\right)\max \left(V_C\right)}{K_t\min \left(V_W\right)}}$

Min (F _t) and max (F _t) be minimum tangential grinding force and the maximum tangential grinding force in the best grinding force interval of emery wheel.Min (V _C) and max (V _C) be minimum rotation speed and the maximum rotational speed of emery wheel.Min (V _W) and max (V _W) be minimum feed speed and the maximum feed speed of emery wheel.

Step D5: select the grinding track: if the surface of workpiece is the plane, then adopt the grinding track of cycloidal type; If surface of the work is surface of revolution, then adopt the grinding track of fractal scanning formula; If surface of the work is other complex profile, then adopt scan line formula grinding track.

The following description of the job step of Robot calibration module 62:

Step e 1: place tactile sensing element and optical sensing element at workpiece, and touching or stimulating apparatus are installed to determine the position relationship between robot end and the workpiece the robot end;

Step e 2: obtain the coordinate transform relation between robot coordinate system and the workpiece coordinate system.

Step e 3: according to the relation of the coordinate transform between robot coordinate system and the workpiece coordinate system, the grinding track that obtains in the grinding trajectory planning module 61 is converted to the end movement track of robot.

Be illustrated in figure 7 as the algorithm flow in the control of grinding force module 63:

Step F 1: in the contactless constraint space of emery wheel 32 and workpiece 7, namely when emery wheel 32 does not contact workpiece 7, in order to remedy the position deviation that causes robot 1 end orbit and surface of the work owing to abrasion of grinding wheel, workpiece installation site deviation, online adaptive Compensating Robot 1 end orbit can keep in touch with surface of the work emery wheel.

Step F 2: in the contiguity constraint space of emery wheel 32 and workpiece 7, namely when emery wheel 32 grinding work piece 7, grinding force data (feedback signal of six-dimension force sensor 51) based on 5 inputs of grinding force detecting unit, the emery wheel 32 of installing on the end of control 1 and the contact force of workpiece 7, concrete steps comprise:

Step F 21: (1≤j≤t) inferior removal amount is gathered { SG according to j _i} _j, and current velocity of rotation and the feed speed of emery wheel, in formula (1) and the j time grinding process of formula (2) calculating, expectation tangential grinding force and expectation normal grinding force.

Step F 22: according to the difference of actual tangential grinding force and expectation tangential grinding force, the difference of actual normal grinding force and expectation normal grinding force, adoption rate-differential-integration (PID) control algolithm, the velocity of rotation V of adjusting emery wheel _CWith feed speed V _W

Step F 23: repeating step F21 and step F 22, until finish the back and forth number of times t of reciprocal grinding.

Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; be understood that; the above only is specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (11)

1. robot grinding system, be used for workpiece (7) is carried out grinding, comprise system's main control system (6), robot (1), be installed on the terminal spindle motor unit (3) of robot (1) and be installed on the emery wheel (32) of the end of spindle motor unit (3), described system main control system (6) is by the rotation to emery wheel (32) of control spindle motor unit (3), and control (1) is terminal that grinding process to workpiece (7) is finished in the translation of emery wheel (32), it is characterized in that:

Described robot grinding system also comprises workpiece profile detecting unit (2), and it produces the workpiece profile data and also flow to system's main control system (6) for detection of the profile of workpiece (7);

Described system main control system (6) produces rotary speed data and feed speed data according to these workpiece profile data, respectively it is inputed to spindle motor unit (3) and robot (1), to control described emery wheel (32) for the grinding process of workpiece (7).

2. robot grinding as claimed in claim 1 system, it is characterized in that, described working profile detecting unit (3) comprises two cameras (21,22), the two-dimentional workpiece image of this two cameras (21,22) Real-time Collection of this working profile detecting unit (3) adopts three-dimensional reconstruction method to make up three-dimensional workpiece profile data.

3. robot grinding as claimed in claim 1 system, it is characterized in that, also comprise abrasion of grinding wheel detecting unit (4), it obtains the abrasion of grinding wheel level data and is transferred to system's main control system (6) for detection of the degree of wear of emery wheel (32);

Described system main control system (6) also produces rotary speed data and feed speed data according to this abrasion of grinding wheel level data.

4. robot grinding as claimed in claim 3 system, it is characterized in that, described abrasion of grinding wheel detecting unit (4) is rebuild the real-time characteristic profile of wheel face by the degree of wear that detects in real time emery wheel (32), this real-time characteristic profile and the feature contour of presetting are compared, calculate the wear extent of emery wheel (32), produce the abrasion of grinding wheel level data.

5. robot grinding as claimed in claim 4 system, it is characterized in that, described abrasion of grinding wheel detecting unit (3) is laser vision sensor, and it comprises binocular camera shooting head and line structure light source, and rebuilds the real-time characteristic profile of wheel face by the line-structured light triangulation.

6. robot grinding as claimed in claim 3 system, it is characterized in that, also comprise grinding force detecting unit (5), it produces the grinding force data and flows to system's main control system (6) for detection of the grinding force between workpiece described in the described grinding process (7) and the described emery wheel (32);

Described system main control system (6) also produces rotary speed data and feed speed data according to these grinding force data.

7. robot grinding as claimed in claim 6 system is characterized in that, described grinding force detecting unit (5) comprises six-dimension force sensor (51) and data acquisition module (52),

Described six-dimension force sensor (41) is installed in the end of described robot (1), for detection of the grinding force between workpiece in the grinding process 7 and the emery wheel 32;

Described data acquisition module (52) is used for gathering tangential component and the normal component of grinding force, and generation grinding force data also are input in system's main control system (6).

8. robot grinding as claimed in claim 6 system is characterized in that, described system main control system (6) comprises grinding trajectory planning module (61), Robot calibration module (62) and control of grinding force module (63), wherein,

Described grinding trajectory planning module (61) is used for obtaining the grinding track of surface of the work according to the workpiece profile data of measuring in real time and the design data of workpiece profile, planning grinding motion track;

Described Robot calibration module (62) is used for setting up the coordinate transform relation between robot coordinate system and the workpiece coordinate system, and the grinding motion track is converted to the end movement track of robot;

Described control of grinding force module (63) is used for according to described grinding force data, abrasion of grinding wheel data, workpiece profile data and location of workpiece data, calculate feed speed and the velocity of rotation of emery wheel, and with the velocity of rotation transfer of data to the described spindle motor unit (3), described feed speed is transferred in the robot (1).

9. robot grinding as claimed in claim 8 system is characterized in that, the algorithm flow of grinding trajectory planning module 61 is:

Step D1: detect data acquisition system { SR from workpiece profile detecting unit (2) input workpiece profile _i(i=1,2 ..., n; N is the quantity of data);

Step D2: in advance storage workpiece profile design data set { SI in system's main control system (6) _i(i=1,2 ..., n; N is the quantity of data);

Step D3:{SR _iAnd { SI _iData carry out man-to-man comparison, calculate its difference, this difference is exactly the removal amount set { SG of surface of the work _i, wherein, i=1,2 ..., n, n are the quantity of data;

Step D4: according to removal amount set { SG _iAnd the best grinding force of emery wheel interval, calculate back and forth back and forth grinding number of times t, and j (the inferior removal amount set { SG of 1≤j≤t) _i} _j, t is for satisfying t _Min≤ t≤t _MaxAn integer, wherein

$t_{\min }=\arcsin \sqrt{2\&CenterDot;\frac{\min \left(F_t\right)\min \left(V_C\right)}{K_t\max \left(V_W\right)}}$

$t_{\max }=\arcsin \sqrt{2\&CenterDot;\frac{\max \left(F_t\right)\max \left(V_C\right)}{K_t\min \left(V_W\right)}},$

Min (F _t) and max (F _t) be minimum tangential grinding force and the maximum tangential grinding force in the best grinding force interval of emery wheel, min (V _C) and max (V _C) be minimum rotation speed and the maximum rotational speed of emery wheel, min (V _W) and max (V _W) be minimum feed speed and the maximum feed speed of emery wheel;

Step D5: select the grinding track: if the surface of workpiece is the plane, then adopt the grinding track of cycloidal type; If surface of the work is surface of revolution, then adopt the grinding track of fractal scanning formula; If surface of the work is other complex profile, then adopt scan line formula grinding track.

10. robot grinding as claimed in claim 8 system is characterized in that, the algorithm flow in the described control of grinding force module (63) is:

Step F 1: in the contactless constraint space of emery wheel (32) and workpiece (7), namely when emery wheel (32) does not contact workpiece (7), in order to remedy the position deviation that causes robot (1) end orbit and surface of the work owing to abrasion of grinding wheel, workpiece installation site deviation, online adaptive Compensating Robot (1) end orbit can keep in touch with surface of the work emery wheel;

Step F 2: in the contiguity constraint space of emery wheel (32) and workpiece (7), namely when emery wheel (32) grinding work piece (7), based on the grinding force data of grinding force detecting unit (5) input, the emery wheel (32) of installing on the end of control (1) and the contact force of workpiece (7).

11. robot grinding as claimed in claim 10 system is characterized in that, described step F 2 comprises:

Step F 21: (1≤j≤t) inferior removal amount is gathered { SG according to j _i} _j, and current velocity of rotation and the feed speed of emery wheel calculated in the j time grinding process expectation tangential grinding force and expectation normal grinding force;

Step F 22: according to the difference of actual tangential grinding force and expectation tangential grinding force, the difference of actual normal grinding force and expectation normal grinding force, adoption rate-differential-integration (PID) control algolithm, the velocity of rotation V of adjusting emery wheel _CWith feed speed V _W

Step F 23: repeating step F21 and step F 22, until finish the back and forth number of times t of reciprocal grinding.

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