Intelligent surface burnishing tool system

Abstract

An intelligent surface burnishing tool system is provided. A surface burnishing tool can directly machine a surface of an irregular rotating workpiece and have a capability of sensing a cutting force and a vibration signal. In addition, according to the present disclosure, based on a multi-sensor integrated intelligent tool combined with a method for on-line monitoring of changes in surface roughness, the changes in workpiece surface roughness during machining are determined. Finally, based on on-line monitoring of the changes in surface roughness of the workpiece, functions such as real-time collection of a multidimensional force and vibration signals during surface burnishing and on-line monitoring of the changes in surface roughness are realized.

What is claimed is: 
     
         1 . An intelligent surface burnishing tool system, comprising an intelligent surface burnishing tool and an on-line sensing device for changes in surface roughness of a workpiece being machined,
 wherein the intelligent surface burnishing tool comprises a burnishing tool head, an intelligent burnishing tool handle, and a laser displacement sensor, the burnishing tool head is mounted on the intelligent burnishing tool handle by a burnishing tool holder of the burnishing tool head;   the intelligent burnishing tool handle comprises a vibration signal sensing measurement section, a cutting force sensing measurement section, and a tool handle clamping section connected to the cutting force sensing measurement section, the vibration signal sensing measurement section measures a vibration signal based on a vibration sensing chip, the cutting force sensing measurement section measures a cutting force signal based on a piezoelectric quartz crystal group, and the laser displacement sensor is mounted on the vibration signal sensing measurement section;   the on-line sensing device for changes in surface roughness of a workpiece being machined is configured to acquire the cutting force signal; calculate a cutting coefficient; reconstruct a phase space; calculate, for each of pairs of points in the phase space, a proportion of a number of the pairs of points meeting a distance threshold to a total number of the pairs of points to obtain a correlation integral; linearly fit the correlation integral and the distance threshold to obtain a correlation dimension of the cutting coefficient, wherein steps of calculating the correlation dimension of the cutting coefficient are as follows:
 1) calculating a delay time by a mutual information method, and calculating an optimal embedding dimension by a false nearest neighbor method; 
 2) reconstructing a phase space: based on a known delay time and the optimal embedding dimension, reconstructing a one-dimensional time series to obtain a reconstruction matrix; 
 3) calculating a correlation integral C(r): firstly selecting a series of distance thresholds r, wherein if a volume element with a radius r contains all phase points in the phase space, a value of C(r) is 1; and if the volume element with a radius r contains no phase point, the value of C(r) is 0; then calculating a Euclidean distance between each of pairs of points in the phase space; finally, calculating, for each of the distance thresholds r, a proportion of a number of the pairs of the points with a distance therebetween less than r to a total number of the pairs of the points: 
   
       
         
           
             
               
                 
                   C 
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                         i 
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                       N 
                     
                     
                       
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                             j 
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                             j 
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                             i 
                           
                         
                         N 
                       
                       
                         H 
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                           ( 
                           
                             r 
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                                   X 
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           wherein X i  and X j  are points in the phase space; N is a number of points in the phase space; and H(⋅) is a Heaviside step function; and 
           4) calculating the correlation dimension: taking a logarithm for each of the distance thresholds r and the correlation integral C(r) for linear fitting, and finally calculating a slope of a fitted straight line to obtain the correlation dimension of the cutting coefficient; and 
         
         determine changes in the surface roughness of the workpiece during surface burnishing machining based on a relationship between the correlation dimension and a surface root mean square height of a workpiece surface after being surface burnishing machined. 
       
     
     
         2 . The intelligent surface burnishing tool system according to  claim 1 , wherein the burnishing tool head comprises a ball head end cover, a burnishing ball head, a burnishing tool holder, and a burnishing ball, wherein the burnishing tool holder is of a cylindrical head bolt structure, and has a front end being of a cylindrical structure and a rear end being of a screw structure; the cylindrical front end is provided with a hemispherical cavity which is internally provided with a positioning groove for the burnishing ball; an annular oil storage cavity is provided below the hemispherical cavity, and an annular oil guide groove is provided between the hemispherical cavity and the annular oil storage cavity; a low end of the annular oil storage cavity is provided with an oil filling hole; the burnishing ball head and the burnishing ball are mounted in the hemispherical cavity by means of the ball head end cover; the ball head end cover is in threaded connection with the burnishing tool holder; and a rear end of the burnishing tool holder is fixedly mounted onto the intelligent burnishing tool handle by the screw structure. 
     
     
         3 . The intelligent surface burnishing tool system according to  claim 1 , wherein the vibration signal sensing measurement section comprises a vibration signal sensing component carrier and a vibration signal sensing component, wherein the vibration signal sensing component carrier is a cuboid with a square cross-section, and has a side surface provided with an L-shaped through groove; the vibration signal sensing component comprises a vibration signal sensing unit carrier and a vibration signal sensing unit; the vibration signal sensing unit carrier is L-shaped and is mounted in the L-shaped through groove of the vibration signal sensing component carrier, and an inner surface of a longer end of the vibration signal sensing unit carrier is provided with a cavity for placing the vibration signal sensing unit; and the vibration sensing unit comprises a circuit board and a vibration sensing chip. 
     
     
         4 . The intelligent surface burnishing tool system according to  claim 1 , wherein the cutting force sensing measurement section comprises a cutting force sensing unit carrier and a cutting force sensing unit, wherein the cutting force sensing unit carrier is a cuboid with a square cross-section provided with a cavity for placing the cutting force sensing unit; and the cutting force sensing unit comprises piezoelectric quartz crystal groups. 
     
     
         5 . The intelligent surface burnishing tool system according to  claim 4 , wherein the cutting force sensing unit is six piezoelectric quartz wafers, the wafers are assembled in pairs to form three crystal groups that are placed in the cavity of the cutting force sensing unit carrier, an electrode sheet is placed between two wafers of each of the three crystal groups, and charges generated by a stress acting on the wafers are collected by the electrode sheet. 
     
     
         6 . The intelligent surface burnishing tool system according to  claim 5 , wherein the cutting force sensing unit uses three quartz crystal groups, comprising an X0° cut crystal group and two Y0° cut crystal groups, force-sensitive directions of which are perpendicular to one another, wherein axial tension-compression forces of the intelligent surface burnishing tool are measured based on a tension-compression effect of the X0° cut crystal group, and tangential shear forces of the intelligent surface burnishing tool are measured based on shear effects of the two Y0° crystal groups. 
     
     
         7 . The intelligent surface burnishing tool system according to  claim 5 , wherein the cutting force sensing measurement section further comprises a cutting force sensing unit end cover, wherein the cutting force sensing unit end cover is in direct contact with the piezoelectric quartz wafers, and a pre-tightening force is applied to the piezoelectric quartz wafers and the vibration signal sensing unit carrier by a bolt to mount the cutting force sensing unit end cover. 
     
     
         8 . The intelligent surface burnishing tool system according to  claim 1 , wherein the laser displacement sensor is configured to measure a distance between a laser probe and a curved surface of a workpiece being tested, keeping a depth by which the burnishing ball is pressed into the surface of the workpiece unchanged during surface burnishing machining.