Surface shape measuring apparatus and control method thereof

Abstract

To provide a surface shape measuring device and a control method capable of minimizing breakage of a stylus, a workpiece or both of them.SOLUTION: And a control device (30) configured to, when the vertical movement section (16) starts to move from a stopped state to an approaching side in the approaching / separating direction where the stylus (22) approaches the surface of the workpiece (W), retract the vertical movement section (16) to a separating side where the stylus (22) separates from the surface of the workpiece (W) and then move the vertical movement section (16) to the approaching side.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a surface shape measuring apparatus and a control method thereof. [Background technology]

[0002] There is known a shape measuring device that measures the surface roughness, contour, and other surface shapes of a workpiece from the displacement of the stylus by moving a detector equipped with a stylus along the surface of the object to be measured (workpiece) using a drive unit. In such a shape measuring device, it is required to prevent damage to the stylus, the workpiece, or both, to improve the life of the stylus, and to preserve the workpiece.

[0003] For example, in the measuring device of Patent Document 1, a holder for a fine stylus is attached to a micro-motion actuator, and when the fine stylus comes into contact with the object to be measured in its axial direction, the stylus is pulled up to remove it from contact to prevent the fine stylus from buckling, and furthermore, the stylus is not allowed to remove it from contact when there is no risk of buckling. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-340544 Summary of the Invention [Problem to be solved by the invention]

[0005] However, providing an actuator as shown in Patent Document 1 requires, for example, a component layout that creates a space for the actuator, which places design restrictions on the device. Furthermore, adding an actuator increases costs.

[0006] Furthermore, in a shape measurement device, when the drive unit supporting the detector starts moving from a stopped state, it suddenly starts moving due to a switch from static friction to dynamic friction. If the stylus is in contact with a workpiece or the like at this time, the energy is transmitted from the tip of the stylus to the workpiece, and the stylus is subjected to a repulsive force. The repulsive force may cause the stylus to separate from the workpiece, which may then collide with the workpiece, potentially damaging the stylus, the workpiece, or both.

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide a surface shape measuring apparatus and a control method thereof that can minimize damage to the stylus, the workpiece, or both. [Means for solving the problem]

[0008] a horizontal drive unit supported by the vertical movement unit and capable of movably holding the detector in a direction perpendicular to the longitudinal direction of the column; a measurement direction information acquisition unit that acquires measurement direction information indicating the measurement direction in which the stylus is brought into contact with the object to be measured; a contact information acquisition unit that acquires contact information indicating whether the stylus is in contact with the object to be measured; and a movement control unit that, upon receiving a movement instruction for the vertical movement unit, controls the movement of the vertical movement unit based on the movement instruction; and, based on the measurement direction information and the contact information, if the stylus is in contact with the object to be measured and the instructed movement direction of the vertical movement unit is the same as the measurement direction, the movement control unit performs a small retraction movement by temporarily moving the vertical movement unit in the direction opposite to the instructed movement direction, and then moves the vertical movement unit in the instructed movement direction.

[0009] In the second aspect of the surface shape measuring device, when the stylus is not in contact with the object to be measured, the movement control unit moves the vertical movement unit in the movement instruction direction without first moving the vertical movement unit in the direction opposite to the movement instruction direction.

[0010] In the third aspect of the surface shape measuring device, when the movement instruction direction of the vertical movement unit instructed to move is opposite to the measurement direction, the movement control unit moves the vertical movement unit in the movement instruction direction without first moving the vertical movement unit in the opposite direction to the movement instruction direction.

[0011] In the surface profile measuring apparatus of the fourth aspect, the movement control section performs a slight retraction movement while maintaining contact between the stylus and the measurement object.

[0012] In the fifth aspect of the surface shape measuring device, when the movement control unit performs a small retraction movement and then moves the vertical movement unit in the movement instruction direction at a specified speed, after performing the small retraction movement, it moves the vertical movement unit in the movement instruction direction at a speed slower than the specified speed, and then moves the vertical movement unit in the movement instruction direction at the specified speed.

[0013] The surface shape measuring apparatus of the sixth aspect includes a setting unit that sets the amount of movement of the vertical moving unit in the minute retraction movement.

[0014] In the seventh aspect of the surface profile measuring device, when measuring the surface profile of the inner surface of a hole formed in the object to be measured, the setting unit sets the movement amount of the vertical movement unit in the minute retraction movement so that it is smaller than the difference between the inner diameter of the hole and the effective height of the stylus.

[0015] In the surface shape measuring device of the eighth aspect, the detector has a measuring force imparting mechanism that can switch the direction of the measuring force imparted to the stylus depending on the measurement direction of the stylus relative to the measurement object, and the measurement direction information acquisition unit acquires measurement direction information based on the switching state of the measuring force in the measuring force imparting mechanism.

[0016] A ninth aspect of the surface shape measuring device further includes a tilt drive unit that tilts the detector relative to the object to be measured by rotating around a direction perpendicular to both the movement direction of the vertical movement unit and the movement direction of the detector by the horizontal drive unit, and a rotation control unit that, upon receiving a rotation instruction from the tilt drive unit, controls the rotation of the tilt drive unit based on the rotation instruction, and when the rotation instruction direction of the tilt drive unit that has been instructed to rotate matches the direction in which the stylus contacts the object to be measured, the rotation control unit performs a small retraction rotation movement to rotate the tilt drive unit in the direction opposite to the rotation instruction direction, and then rotates the tilt drive unit in the rotation instruction direction.

[0017] A tenth aspect of the control method for a surface profile measuring device is a control method for a surface profile measuring device that measures the surface profile of a measurement object, the surface profile measuring device comprising: a detector having a stylus that contacts the surface of the measurement object and a displacement detection unit that detects displacement of the stylus; a column that is erected vertically relative to a base on which the measurement object is placed; a drive unit provided on the column; a vertical movement unit connected to the drive unit and capable of sliding movement along the longitudinal direction of the column; and a horizontal drive unit supported by the vertical movement unit and holding the detector movably in a direction perpendicular to the longitudinal direction of the column, the surface profile measuring device acquiring measurement direction information that indicates the measurement direction in which the stylus is brought into contact with the measurement object; acquiring contact information that indicates whether the stylus is in contact with the measurement object; accepting a movement instruction for the vertical movement unit; and, based on the measurement direction information and the contact information, if it is determined that the stylus is in contact with the measurement object and the instructed movement direction of the vertical movement unit is the same as the measurement direction, performing a small retraction movement in which the vertical movement unit is temporarily moved in the opposite direction to the instructed movement direction, and then moving the vertical movement unit in the instructed movement direction. [Effects of the Invention]

[0018] The present invention can minimize damage to the stylus, the workpiece, or both. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram of a surface profile measuring device. [Figure 2] FIG. 2 is a schematic diagram of the horizontal drive and detector. [Figure 3] Figure 3 is a schematic diagram of the column and vertical movement section. [Figure 4] FIG. 4 is a diagram for explaining the force that the vertical moving part receives from the column. [Figure 5] FIG. 5 is a diagram illustrating the movement of the stylus when the movement of the vertical moving part switches from static friction to dynamic friction. [Figure 6] FIG. 6 shows the results of measuring the damage to the workpiece. [Figure 7] Figure 7 is a graph showing the relationship between the thrust required to start moving and the stopping time. [Figure 8] FIG. 8 is a block diagram showing the configuration of the surface shape measuring device. [Figure 9] FIG. 9 is a flowchart showing a method for controlling the surface shape measuring device. [Figure 10] FIG. 10 is a diagram for explaining the minute retreat movement of the vertical moving part and the movement in the designated movement direction when the measurement direction is downward. [Figure 11] FIG. 11 is a diagram for explaining the speed command value, the actual speed, and the actual position of the vertical moving part in the minute retreat movement of the vertical moving part and the movement in the designated movement direction. [Figure 12] FIG. 12 is a diagram showing an example of the movement of the vertical moving part when the stylus is not in contact with the workpiece. [Figure 13] FIG. 13 is a diagram showing an example of the movement of the vertical moving part when the stylus comes into contact with the workpiece and the movement instruction direction and the measurement direction are opposite to each other. [Figure 14] FIG. 14 is a diagram for explaining the minute retreat movement and movement in the designated movement direction when the measurement direction is upward. [Figure 15] FIG. 15 is a diagram for explaining the setting of the movement amount in the minute retreat movement. [Figure 16] FIG. 16 is a schematic diagram of another type of surface shape measuring device. [Figure 17] FIG. 17 is a diagram for explaining the minute retraction rotational movement of the tilt drive unit and the rotation of the tilt drive unit. DETAILED DESCRIPTION OF THE INVENTION

[0020] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0021] <Surface shape measuring device> Fig. 1 is a schematic diagram of a surface profile measuring apparatus 10. As shown in Fig. 1, the surface profile measuring apparatus 10 measures the shape of the surface of a workpiece W, specifically, the contour shape or surface roughness, etc. Here, the workpiece W corresponds to the measurement object of the present invention. In addition, of the mutually orthogonal X, Y and Z directions in the figure, the XY plane including the XY directions is a plane parallel to the horizontal direction, and the Z direction is an up-down direction perpendicular to the horizontal direction.

[0022] The surface profile measuring device 10 comprises a flat-topped, plate-shaped base 12, a column 14, a vertical moving unit 16, a horizontal driving unit 18, a detector 20 having a stylus 22, an operating unit 24, a monitor 26, and a control device 30.

[0023] A workpiece W is placed on the upper surface of the base 12, which is parallel to the XY plane. A column 14 is erected in the Z direction (vertical direction) relative to the upper surface of the base 12. A vertical moving unit 16 is attached to the column 14 so as to be slidable along the longitudinal direction of the column 14.

[0024] A horizontal drive unit 18 is supported by the vertical movement unit 16. The horizontal drive unit 18 holds the detector 20 so that it can move in a direction (X direction) perpendicular to the longitudinal direction of the column 14. By driving the horizontal drive unit 18, the detector 20 (the stylus 22) is moved in the X direction relative to the workpiece W. It is possible.

[0025] The operation unit 24 uses, for example, a keyboard, a mouse, an operation panel, and operation buttons, and receives inputs of various operations by an operator.

[0026] Various displays such as a known liquid crystal display are used as the monitor 26. The monitor 26 displays the surface shape measurement results obtained by the surface shape measuring device 10, various setting screens, various operation screens, and the like.

[0027] The control device 30 includes an arithmetic circuit configured with various processors, memories, etc. The various processors include a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), and a programmable logic device (e.g., simple programmable logic device (SPLD), complex programmable logic device (CPLD), and field programmable gate array (FPGA)). The various functions of the control device 30 may be realized by a single processor, or may be realized by multiple processors of the same or different types.

[0028] <Horizontal drive unit> 2 is a schematic diagram of the horizontal drive unit 18 and the detector 20. As shown in FIG. 2, the horizontal drive unit 18 includes a rail 40, a slider 42, a ball screw 44, a motor 46, and an X-position detection mechanism 48.

[0029] The rail 40 extends along the X direction. A slider 42 is attached on the rail 40 so as to be movable in the X direction. A ball screw 44 is provided along the rail 40. The slider 42 is screwed onto the ball screw 44.

[0030] A motor 46 is attached to rotate the ball screw 44. The motor 46 rotates the ball screw 44, and this rotational motion is converted into linear motion by the slider 42 and the ball screw 44, allowing the detector 20 attached to the slider 42 to move in the X direction (horizontal direction).

[0031] The X-position detection mechanism 48 can detect the position of the slider 42 in the X direction, thereby detecting the X-direction position of the detector 20, i.e., the X-direction position of the detector 20 relative to the workpiece W. The detection result of the X-position detection mechanism 48 is input to the control device 30.

[0032] <Detector> As shown in FIG. 2, the detector 20 includes a stylus 22, an arm 50, a swing fulcrum 52, a measuring force imparting mechanism 54, and a displacement detection unit 56.

[0033] The swing support 52 supports the arm 50 so that it can swing freely around a rotation axis (swing axis) parallel to the Y direction.

[0034] The arm 50 is supported so as to be able to swing freely on a swing fulcrum 52. For example, the arm 50 can be configured with an arm tip 50A extending in one direction in the X direction (the side opposite to the column 14) and having the stylus 22 provided thereon, and an arm base 50B extending in the other direction in the X direction.

[0035] By making the arm tip end 50A and the arm base end 50B detachable, a plurality of types of stylus 22 according to the shape of the workpiece W can be easily replaced.

[0036] A stylus 22 (also called a contactor or a measuring element) is provided on the tip side of the arm tip portion 50A. The stylus 22 comes into contact with the surface of the workpiece W. The stylus 22 is displaced in the Z direction as the arm 50 swings around the swing fulcrum 52. Furthermore, the horizontal drive unit 18 moves the detector 20 in the X direction, causing the stylus 22 to trace (scan) the surface of the workpiece W along the X direction.

[0037] When the stylus 22 is brought into contact with the workpiece W, the measuring force imparting mechanism 54 imparts a measuring force, which is a biasing force toward the workpiece W, to the stylus 22. This causes the tip of the stylus 22 to abut against the surface of the workpiece W.

[0038] The measuring force imparting mechanism 54 is configured to be able to switch the direction of the measuring force imparted to the stylus 22 depending on the measurement direction of the stylus 22 relative to the workpiece W.

[0039] 2, when the workpiece W is located below the stylus 22 in the Z direction, a downward measuring force in the Z direction is applied to the stylus 22. On the other hand, when the workpiece W is located above the stylus 22 in the Z direction, an upward measuring force in the Z direction is applied to the stylus 22.

[0040] The measurement direction of the measuring force imparting mechanism 54 is set by the control device 30. A spring, a weight, or the like is used as the measuring force imparting mechanism 54. There are no limitations on the configuration of the measuring force imparting mechanism 54 as long as it can impart a measuring force.

[0041] The displacement detection unit 56 can detect the rotation angle or displacement in the Z direction due to the swing of the stylus 22. The detection results of the displacement detection unit 56 are input to the control device 30. As the displacement detection unit 56, for example, a Linear Variable Differential Transformer (LVDT), a linear scale, or a circular scale is applied. There are no limitations on the displacement detection unit 56 as long as it can detect the displacement of the stylus 22.

[0042] <Column and vertical moving part> Fig. 3 is a schematic diagram of the column 14 and the vertical moving unit 16. As shown in Fig. 3, the column 14 has a columnar housing that extends in the vertical direction (Z direction) relative to the base 12 (see Fig. 1).

[0043] The column 14 has an accommodation space therein, and a ball screw 62 is attached to this accommodation space. The ball screw 62 extends along the Z direction of the column 14. The upper end of the ball screw 62 protrudes from the column 14.

[0044] A motor 64 for rotating the ball screw 62 is provided at the upper end of the ball screw 62, and the ball screw 62 and motor 64 function as a drive unit that drives the vertical moving unit 16. A Z-position detection mechanism 66 is provided, which can detect the Z-direction position of the vertical moving unit 16 (the amount of movement in the Z direction). As the Z-position detection mechanism 66, for example, an encoder, a Z-position scale, or the like can be used. However, there are no particular limitations on the Z-position detection mechanism 66 as long as it can detect the Z-direction position of the vertical moving unit 16. The detection result of the Z-position detection mechanism 66 is input to the control device 30.

[0045] The vertical moving portion 16 includes a column insertion hole 70 through which the column 14 can be inserted, a nut 72, a sliding member 74, and a pressure mechanism 76.

[0046] As shown in FIG. 3, the column insertion hole 70 of the vertical moving portion 16 extends in the Z direction, and the column 14 is inserted therethrough.

[0047] The nut 72 of the vertical moving unit 16 is threadedly engaged with the ball screw 62 that constitutes the drive unit, thereby connecting the vertical moving unit 16 to the drive unit. When the ball screw 62 is rotated by the motor 64, this rotational motion is converted into linear motion by the nut 72 and the ball screw 62, and the nut 72 moves along the longitudinal direction of the ball screw 62. The movement direction and speed of the vertical moving unit 16 are controlled by movement instructions and speed instructions from the control device 30.

[0048] On each surface constituting the column insertion hole 70 of the vertical moving part 16, a sliding member 74 is provided that frictionally slides against the side surface of the column 14 when the vertical moving part 16 moves up and down along the column 14. Furthermore, each sliding member 74 is provided with a pressure mechanism 76 that applies a pressing force to the sliding member 74 against the column 14.

[0049] The relative position between the vertical moving part 16 and the column 14 is determined by the position to which the nut 72 is moved by the rotation of the ball screw 62 , and the relative position is maintained by the frictional force of the sliding member 74 .

[0050] The vertical moving part 16 moves along the longitudinal direction of the column 14 via this nut 72 while sliding with friction on the side surface of the column 14 .

[0051] <Background of the Invention> The inventors have thoroughly investigated damage to the stylus 22 and the workpiece W in the above-described surface shape measuring device 10, and as a result have found the following problem, leading to the present invention. The problem found by the inventors will now be described.

[0052] When the vertical moving part 16 supporting the detector 20 starts moving from a stopped state on the column 14, the vertical moving part 16 may suddenly start moving due to the change from static friction to dynamic friction.

[0053] 4 is a diagram for explaining the forces acting on the vertical moving section 16 and the column 14. For ease of understanding, the pressurizing mechanism 76 and gravity are omitted.

[0054] 1004A shows the state when the stopped vertical moving part 16 moves downward along the longitudinal direction of the column 14. As shown in 1004A, the vertical moving part 16 and the column 14 are subjected to a normal force F NF , thrust F T and static friction force F S receive.

[0055] Normal force F NF is the reaction force of the pressing force applied to the sliding member 74 by the pressurizing mechanism 76. NF is a force perpendicular to the longitudinal direction of the column 14 and directed toward the sliding member 74. NF The magnitude of the pressure is determined by the pressing force of the pressure mechanism 76.

[0056] Thrust F T is a force that the nut 72 receives from the ball screw 62 due to the rotation of the motor 64, and is an upward or downward force along the longitudinal direction of the column 14. T The magnitude and orientation of the is determined by a motor 66 controlled by the controller 30.

[0057] Static friction force F S is the coefficient of static friction and normal force F NF The force determined by the thrust F T The static friction coefficient is determined by the materials and surface properties of the column 14 and the sliding member 74.

[0058] In order to move the vertical moving part 16, a static friction force F S The output torque of the motor 64 is increased until it balances with the thrust F T The output of the motor 64 is controlled by a control device 30 (not shown).

[0059] 1004B shows a state in which the vertical moving part 16 starts to move downward along the longitudinal direction of the column 14. As shown in 1004B, the vertical moving part 16 and the column 14 are subjected to a normal force F NF , thrust F T and kinetic friction force F D receive.

[0060] Dynamic friction force F D is the coefficient of kinetic friction and normal force F NF The force determined by the thrust F T This results in a force in the opposite direction to that of the force.

[0061] Generally, the coefficient of kinetic friction is smaller than the coefficient of static friction, so the static friction force F S >Dynamic friction force F D As a result, the frictional force decreases as shown by 1004B, and the vertical moving part 16 receives a large acceleration and moves downward.

[0062] 1004C shows the state in which the vertical moving part 16 moves downward along the longitudinal direction of the column 14 after starting to move.

[0063] After the vertical moving part 16 starts moving, as shown in 1004C, the vertical moving part 16 and the column 14 are subjected to a normal force F NF , thrust F T and kinetic friction force F D receive.

[0064] In order to move the vertical moving part 16 at the target speed, a kinetic friction force F D The output torque of the motor 64 is suppressed to balance out the thrust F T The output of the motor 64 is controlled by the control device 30 (not shown) in accordance with the detection result of the Z position detection mechanism 66 so as to achieve a target speed.

[0065] In the state of 1004C, the vertical moving part 16 and the column 14 are subjected to a stable kinetic friction force F D Therefore, the movement of the vertical moving part 16 is stably controlled by the control device 30.

[0066] Next, the movement of the stylus 22 caused by the switch from static friction to dynamic friction when the vertical moving part 16 starts moving from a stopped state will be explained with reference to Figure 5. For ease of understanding, the horizontal driving part 18 and the detector 20 are omitted from Figure 5.

[0067] 5 correspond to 1004A, 1004B and 1004C in FIG. 4, respectively.

[0068] 5, the measurement direction is downward, with the workpiece W positioned below the stylus 22, and the movement direction of the vertical moving unit 16 is downward. Therefore, this is the case where the movement direction of the vertical moving unit 16 instructed by the control device 30 is the same as the measurement direction.

[0069] 1005A shows a state in which the stylus 22 is in contact with the workpiece W and the vertical moving unit 16 is being moved downward along the longitudinal direction of the column 14 as indicated by the arrow A by the control device 30 from a stopped state. T is the static friction force F S The vertical moving part 16 will not move until it is balanced by the force.

[0070] 1005B shows the state where static friction is switched to dynamic friction and the vertical moving part 16 starts to move. When static friction is switched to dynamic friction, the static friction force F SFrom the kinetic friction force F D Therefore, energy E is generated to start the movement, and this energy E is completed throughout the entire system. At this time, if the stylus 22 is in contact with the workpiece W, this energy E is transmitted from the tip of the stylus 22 to the workpiece W. Then, the stylus 22 receives a repulsive force R from the workpiece W, causing it to jump up in the direction of arrow B.

[0071] 1005C shows a state in which the vertical moving part 16 slides along the longitudinal direction of the column 14 at a constant speed. At this time, the stylus 22 that has bounced up to 1005B falls as shown by arrow C, collides with the workpiece W, and returns to its normal position. This collision causes damage to the workpiece W (a dent) or damage to the stylus 22.

[0072] 6 shows the results of measuring the needle mark (workpiece dent) on the workpiece W after the stylus 22 collides with the workpiece W using a white light interference microscope (manufactured by Tokyo Seimitsu Co., Ltd.: product name "Opt-scope"). 1006A shows the results when the amount of bouncing of the stylus 22 is small, and 1006B shows the results when the amount of bouncing of the stylus 22 is large. The circled area in the figure indicates the position and depth of the needle mark.

[0073] 1006A and 1006B each indicate by a shade of color the height (μm) of the surface of the workpiece W. In 1006A and 1006B, the range of the surface height is a scale from −4.0 (μm) to 3.0 (μm).

[0074] In 1006A, the circled region is approximately 2.5 μm deep, and in 1006B, the circled region is approximately 4.0 μm deep. It can be seen that the damage depth in 1006B is deeper than that in 1006A, and that the damage depth increases as the bounce of the stylus 22 increases.

[0075] It is also possible to predict the energy E in advance and control the movement of the vertical moving part 16. However, depending on the time that the vertical moving part 16 is stopped on the column 14, the thrust F required to start moving may be TSince the distance between the vertical moving portion 16 and the vertical moving portion 16 changes, it is difficult to predict the distance between the vertical moving portion 16 and the vertical moving portion 16 in advance.

[0076] FIG. 7 is a graph showing the relationship between the thrust force required to start moving and the stopping time. The horizontal axis shows the stopping time [s], and the vertical axis shows the thrust force required to start moving [arb.: arbitrary unit]. As shown in the graph of FIG. 7, the thrust force F required to start moving depends on the time that the vertical moving part 16 is stopped on the column 14. T The relationship between the stopping time and the increase in thrust is presumed to depend on the materials and temperatures of the column 14 and the sliding member 74, and sticking of the sliding member 74 to the column 14 is also considered to be a factor.

[0077] The thrust required to start moving is F T As the force increases, the drive system (belt and feed screw) accumulates energy E due to elastic deformation, and when it starts moving, this energy is suddenly released, causing a sudden acceleration of the vertical moving part 16. As a result, the stylus 22 jumps up, which can cause damage to the stylus 22 and the workpiece W.

[0078] In order to reduce the energy E, the pressing force applied from the pressurizing mechanism 76 to the sliding member 74 is reduced, and the static friction force F S However, the static friction force F S Reducing this distance weakens the holding force of the vertical moving part 16 relative to the column 14, which may result in a decrease in the positioning accuracy of the vertical moving part 16 and the occurrence of drift, where the vertical moving part 16 moves even when stopped.

[0079] <Control of surface shape measuring device> In order to solve the above-mentioned problems, the inventor discovered that when the probe 22 is in contact with the workpiece W, if the measurement direction, which is the direction in which the probe is brought into contact with the workpiece W, is the same as the movement command direction of the vertical moving unit 16, damage to the probe 22, the workpiece W, or both can be minimized by performing a slight retraction movement in which the vertical moving unit 16 is first moved in the opposite direction to the movement command direction, and then moving the vertical moving unit 16 in the movement command direction, and thus came up with the present invention.

[0080] The control of the vertical moving unit 16 of the surface profile measuring apparatus 10 will now be described.

[0081] FIG. 8 is a block diagram showing an example of the configuration of the surface profile measuring device 10. As shown in FIG.

[0082] The control device 30 includes a control unit 100, a memory unit 102, an input unit 104, a display control unit 106, a detection data acquisition unit 108, a movement control unit 110, a measuring force application control unit 112, a measurement direction information acquisition unit 114, a contact information acquisition unit 116, and a movement amount setting unit 118.

[0083] The control unit 100 manages the overall operation of the surface profile measuring apparatus 10. The control unit 100 executes various programs based on acquired or input information, and transmits control signals, various data, processing results, various programs, etc. to each unit.

[0084] The storage unit 102 stores various programs, detected data, processing results based on the detected data, etc. The storage unit 102 is configured with, for example, a ROM, a RAM, a hard disk, etc.

[0085] The input unit 104 acquires information input from the operation unit 24. The input unit 104 transmits a signal corresponding to the input information to each unit, such as the control unit 100.

[0086] The display control unit 106 transmits a signal corresponding to the information to be displayed on the monitor 26 to the monitor 26. The monitor 26 displays the information represented by the signal transmitted from the display control unit 106.

[0087] The detection data acquisition unit 108 acquires detection data from the displacement detection unit 56, the X-position detection mechanism 48, and the Z-position detection mechanism 66. The displacement amount of the stylus 22 is detected from the displacement detection unit 56, the X-position detection mechanism 48 detects the amount of movement of the detector 20 in the X-axis direction (horizontal direction), and the Z-position detection mechanism 66 detects the amount of movement of the vertical movement unit 16 in the Z-axis direction (vertical direction).

[0088] The movement control unit 110 controls the movement, direction and speed of the vertical movement unit 16 and the horizontal drive unit 18 based on a movement instruction signal from the control unit 100 or a movement instruction signal manually input from the operation unit 24 via the input unit 104. The direction and speed of movement can be controlled by, for example, the direction and speed of rotation of the motors 46 and 64.

[0089] As will be described later, based on the specified movement direction of the vertical moving unit 16, measurement direction information, and contact information, if the stylus 22 is in contact with the workpiece W and the specified movement direction of the vertical moving unit 16 is the same as the measurement direction, the movement control unit 110 performs a small retraction movement to move the vertical moving unit 16 in the opposite direction to the specified movement direction, and then moves the vertical moving unit 16 in the specified movement direction.

[0090] The measuring force application control unit 112 controls the operation, measuring force, and measurement direction of the measuring force application mechanism 54 provided in the detector 20. The measuring force application control unit 112 is controlled based on a signal from the control unit 100 or a signal input from the operation unit 24 via the input unit 104.

[0091] The measurement direction information acquisition unit 114 acquires measurement direction information indicating the measurement direction, which is the direction in which the stylus 22 is brought into contact with the workpiece W. The measurement direction information acquisition unit 114 acquires measurement direction information relating to the up and down measurement direction from the measurement direction setting in the control unit 100 or the switching state of the measuring force imparting mechanism 54.

[0092] The contact information acquisition unit 116 acquires contact information indicating whether or not the stylus 22 is in contact with the workpiece W. The contact information acquisition unit 116 acquires the contact information indicating whether or not there is contact from information from the displacement detection unit 56 of the detector 20.

[0093] The movement amount setting unit 118 sets the movement amount of the vertical movement unit 16 in the micro-retraction movement described below. The movement amount setting unit 118 can acquire the movement amount input from the operation unit 24 via the input unit 104. A signal including information on the movement amount set by the movement amount setting unit 118 is transmitted to the movement control unit 110.

[0094] 9 is a flowchart of the control of the surface profile measuring apparatus 10 according to the embodiment. The control of the surface profile measuring apparatus 10 will be described with reference to FIG.

[0095] Here, as shown in FIG. 1, an example will be described in which the workpiece W is placed on the upper surface of the base 12, the stylus 22 faces downward relative to the workpiece W, and the measurement direction is downward.

[0096] 1, a workpiece W is placed on a base 12, and the vertical moving unit 16 and the horizontal driving unit 18 are driven to bring the stylus 22 into contact with the surface of the workpiece W. The stylus 22, to which a measuring force is applied by the measuring force applying mechanism 54, traces (scans) the surface of the workpiece W along the X direction as the detector 20 is moved in the X direction by the horizontal driving unit 18.

[0097] When measuring the workpiece W, there may arise a situation where the vertical moving unit 16 needs to be moved in the same direction as the measurement direction or in the opposite direction to the measurement direction, such as when it is desired to change the relative position between the detector 20 (the stylus 22) and the workpiece W, or when the measurement of the workpiece W has been completed. In such a situation, the control method of the embodiment can be suitably applied.

[0098] 9, measurement direction information indicating the measurement direction, which is the direction in which the stylus 22 is brought into contact with the workpiece W, is acquired (step S10). As described above, the measurement direction information acquiring unit 114 acquires the measurement direction information from the measurement direction setting in the control unit 100 or the switching state of the measuring force imparting mechanism 54. Here, downward measurement direction information is acquired.

[0099] Next, contact information indicating whether or not the stylus 22 is in contact with the workpiece W is acquired (step S12). As described above, the contact information indicating whether or not there is contact is acquired by the contact information acquiring unit 116 from information from the displacement detecting unit 56 of the detector 20.

[0100] Next, the movement control unit 110 receives an instruction to move the vertical movement unit 16 (step S14). As described above, the movement control unit 110 receives an instruction to move the vertical movement unit 16 from the control unit 100 or the operation unit 24. However, the movement control unit 110 does not move the vertical movement unit 16 until it executes the determination in step S16 and / or step S18 below.

[0101] Next, the movement control unit 110 determines whether or not the contact stylus 22 is in contact with the workpiece W based on the contact information acquired by the contact information acquisition unit 116 (step S16). In step S16, if the movement control unit 110 determines that the contact stylus 22 and the workpiece W are in contact (are in contact), the determination is Yes. If the determination is Yes, the process proceeds to step S18.

[0102] On the other hand, in step S16, the determination is No if the movement control unit 110 determines that there is no contact (is not in contact) between the stylus 22 and the workpiece W. If the determination is No, the process proceeds to step S22.

[0103] Next, based on the measurement direction information acquired by the measurement direction information acquisition unit 114, the movement control unit 110 determines whether the movement instruction direction of the instructed vertical movement unit 16 and the measurement direction are the same (step S18). In step S18, if the movement control unit 110 determines that the movement instruction direction and the measurement direction are the same, the result is Yes. If the result is Yes, the process proceeds to step S20.

[0104] On the other hand, in step S18, if the movement control unit 110 determines that the movement instruction direction and the measurement direction are opposite directions, the result is No. If the result is No, the process proceeds to step S22.

[0105] Next, the movement control unit 110 performs a minute retraction movement to temporarily move the vertical movement unit 16 in the direction opposite to the instructed movement direction (step S20). In step S20, the movement control unit 110 issues a command to the motor 64 to move the vertical movement unit 16 by a minute amount in the direction opposite to the instructed movement direction.

[0106] Next, the movement control unit 110 moves the vertical movement unit 16 in the movement instruction direction (step S22). In step S22, the movement control unit 110 issues a command to the motor 64 to move the vertical movement unit 16 in the movement instruction direction to the specified target position.

[0107] Next, the minute retraction movement and movement in the movement instruction direction of the vertical moving unit 16 in steps S20 and S22 will be described with reference to Fig. 10. Fig. 10 shows the case where the workpiece W is positioned below the stylus 22 and faces downward in the measurement direction.

[0108] 1010A indicates the state in which the stylus 22 is in contact with the workpiece W and the measurement direction D M and the movement instruction direction D are the same direction. In this case, in step S20, the movement control unit 110 temporarily causes the vertical movement unit 16 to slightly retreat in the movement direction M1 (upward) indicated by the arrow in the opposite direction to the movement instruction direction D.

[0109] 1010C is a graph in which the horizontal axis represents time and the vertical axis represents velocity. As shown in 1010C, in the minute retreat movement of 1010A, the movement control unit 110 controls the vertical movement unit 16 at a velocity V bk Then, the object is slightly retracted in the direction of movement M1 for a certain period of time.

[0110] When the vertical moving part 16 is slightly retracted in the moving direction M1, the vertical moving part 16 starts to move suddenly due to the change from static friction to dynamic friction.

[0111] However, the vertical moving part 16 moves in the measuring direction D M Since the vertical movement part 16 moves in the opposite direction (the direction of movement M1) to the workpiece W, even if the probe 22 is in contact with the workpiece W, energy is not transmitted from the tip of the probe 22 to the workpiece W. The probe 22 does not receive a reaction force from the workpiece W, so the probe 22 does not jump up. In other words, since the vertical movement part 16 first moves a small amount in a direction away from the workpiece W, no energy (impact) is applied to the workpiece W, and therefore damage to the probe 22 and the workpiece W can be minimized.

[0112] Next, as shown in 1010B, in step S22, the movement control unit 110 moves the vertical movement unit 16 that has performed the minute retreat movement in the movement direction M2 indicated by the arrow, which is the movement instruction direction D (downward).

[0113] As shown in 1010C, in the movement in the movement instruction direction D of 1010B, the movement control unit 110 controls the vertical movement unit 16 at a speed V fw1 Then, the robot moves in the direction M2, which is the movement instruction direction D, for a certain period of time. ... fw1 The specified velocity V fw2 and moves it in movement direction M2, which is the commanded movement direction D. In the movement of 1010B in the commanded movement direction D, the friction has been switched to dynamic friction, so that the vertical moving unit 16 can move stably in the commanded movement direction D.

[0114] In addition, since the movement of the vertical moving unit 16 is switched from the movement direction M1 of the minute retraction movement to the movement direction M2 of the movement command direction D in a short time, there is no time to switch to static friction force, or sticking of the sliding member 74 due to the passage of time (see FIG. 7) can be minimized. As a result, it is possible to prevent the vertical moving unit 16 from suddenly starting to move when starting to move in the movement command direction D.

[0115] In either step S20 or step S22, the energy when the stylus 22 moves toward the workpiece W can be minimized, and damage to the workpiece W and the tip of the stylus 22 can be minimized, contributing to an improvement in the life of the stylus 22 and the preservation of the workpiece W. Furthermore, since there is no need to provide an actuator or the like in the detector 20, design constraints can be relaxed.

[0116] In step S20, it is preferable to perform the slight retraction movement while maintaining contact between the stylus 22 and the workpiece W. If the stylus 22 is in contact with the workpiece W, it is possible to avoid the stylus 22 colliding with the workpiece W when the vertical moving unit 16 moves in the movement direction M2 of the movement instruction direction D.

[0117] In the movement in the movement instruction direction D of 1010B, as shown in 1010C, the operation command from the movement control unit 110 is “to move in the movement instruction direction D at a speed V fw2 In the case of "move with V", first fw1 <V fw2 The velocity V fw1 The vertical moving unit 16 is moved in the movement instruction direction D for a certain period of time, and then moved at a specified speed V fw2 and move in the movement command direction D.

[0118] That is, a movement sequence is executed in which the movement in the instructed movement direction D is made up of two steps: a movement in the instructed movement direction D at a low speed, and a movement in the instructed movement direction D at the instructed speed.

[0119] If the specified speed V is V, the movement direction M1 of the minute retreat movement is switched to the movement direction M2 of the movement instruction direction D. fw2 If the vertical moving unit 16 is moved by the command of V, the speed difference is large, so there is a possibility that a large impact will occur. fw2 before reaching a speed V fw2 Slower speed V fw1 By performing the movement time in this manner, it is possible to mitigate the impact and more effectively protect the tip of the stylus 22 and the workpiece W. However, the movement in the movement direction M2 is not limited to two steps. For example, one step, three steps, etc. can be applied.

[0120] Next, the speed command value, actual speed, and actual position of the vertical moving unit 16 when switching from the movement direction M1 of the minute retreat movement to the movement direction M2 of the movement instruction direction D will be described with reference to FIG.

[0121] 1011A is a graph with the horizontal axis representing time and the vertical axis representing the speed command value, and shows the speed command value given to the motor 64 by the movement control unit 110 over time. As shown in 1011A, the speed command value V bk , V fw1 , V fw2 A signal having a waveform (square wave and triangular wave) representing the above is sent to the motor 64.

[0122] 1011B is a graph with the horizontal axis representing time and the vertical axis representing actual speed, showing the actual speed of the vertical moving part 16 over time. Also, 1011C is a graph with the horizontal axis representing time and the vertical axis representing the position of the vertical moving part 16, showing the actual position of the vertical moving part 16 over time. As circled by the dashed line, when viewed over a short period of time, the initial movement is caused by the stickiness between the sliding member 74 and the surface of the column 14, and the thrust F T is insufficient, the vertical moving part 16 does not move, and the thrust F of the motor 64 T When the arrow rises, the vertical moving part 16 starts to move.

[0123] Furthermore, as shown in 1011C, when the moving direction M1 of the vertical moving part 16 is switched to the moving direction M2 as circled by a solid line, the time for which the vertical moving part 16 is in the same position is short, so the thrust F T It is considered that there is no increase in the amount of energy generated when the moving direction M1 is switched to the moving direction M2.

[0124] 12, an example of the movement of the vertical moving part 16 when the stylus 22 is not in contact with the workpiece W will be described. That is, this is the case where the determination in step S16 is No and the process proceeds to step S22.

[0125] 1012A indicates a state in which the stylus 22 is not in contact with the workpiece W and the measurement direction D M is opposite to the instructed movement direction D. In this case, in step S22, the movement control unit 110 moves the vertical movement unit 16 in a movement direction M1 that is the same direction as the instructed movement direction D (upward).

[0126] 1012C is a graph with the horizontal axis representing time and the vertical axis representing velocity, and corresponds to the movement of 1012A. As shown in 1012C, the movement control unit 110 moves the vertical moving unit 16 at a velocity V fw1 Then, the robot moves in the direction M1, which is the movement instruction direction D, for a certain period of time. ... fw1 The specified velocity Vfw2 and moves in a movement direction M1, which is the instructed movement direction D. However, the movement in the movement direction M1 is not limited to two steps.

[0127] 1012B is a state in which the stylus 22 is not in contact with the workpiece W and the measurement direction D M and the instructed movement direction D are the same direction. In this case, in step S22, the movement control unit 110 moves the vertical movement unit 16 in a movement direction M1 that is the same direction as the instructed movement direction D (downward).

[0128] 1012D is a graph with time on the horizontal axis and velocity on the vertical axis, and corresponds to the movement of 1012B. As shown in 1012D, the movement control unit 110 moves the vertical moving unit 16 at a velocity V fw1 Then, the robot moves in the direction M1, which is the movement instruction direction D, for a certain period of time. ... fw1 The specified velocity V fw2 and moves in a movement direction M1, which is the instructed movement direction D. However, the movement in the movement direction M1 is not limited to two steps.

[0129] In FIG. 12, the vertical moving unit 16 is moved in a movement direction M1, which is the movement instruction direction D, without first moving the vertical moving unit 16 in the direction opposite to the movement instruction direction D.

[0130] Next, based on FIG. 13, when the stylus 22 and the workpiece W are in contact with each other and the movement instruction direction D and the measurement direction D are M An example of the movement of the vertical moving unit 16 when the direction of movement is opposite to that of the vertical moving unit 16 will be described below. That is, the determination in step S16 is Yes, and the determination in step S18 is No, so the process proceeds to step S22.

[0131] 1013A indicates the state where the stylus 22 is in contact with the workpiece W and the measurement direction D M is opposite to the instructed movement direction D. In this case, in step S22, the movement control unit 110 moves the vertical movement unit 16 in a movement direction M1 that is the same direction as the instructed movement direction D (upward).

[0132] 1013B is a graph with time on the horizontal axis and velocity on the vertical axis. As shown in 1013B, the movement control unit 110 moves the vertical movement unit 16 at a velocity V fw1 Then, the robot moves in the direction M1, which is the movement instruction direction D, for a certain period of time. ... fw1 The specified velocity V fw2 and moves in a movement direction M1, which is the instructed movement direction D. However, the movement in the movement direction M1 is not limited to two steps.

[0133] In FIG. 13, the vertical moving unit 16 is moved in a movement direction M1, which is the movement instruction direction D, without first moving the vertical moving unit 16 in the direction opposite to the movement instruction direction D.

[0134] 14, a description will be given of the minute retraction movement and movement in the movement instruction direction when the workpiece W is positioned above the stylus 22 and facing upward in the measurement direction. The measurement direction is different from that in FIG.

[0135] 1014A is the measurement direction D M is facing upward, the stylus 22 is in contact with the workpiece W, and the measurement direction D M and the movement instruction direction D are the same direction. In this case, in step S20, the movement control unit 110 temporarily causes the vertical movement unit 16 to slightly retreat in the direction of movement direction M1 (downward) indicated by the arrow opposite to the movement instruction direction D.

[0136] 1014C is a graph in which the horizontal axis represents time and the vertical axis represents velocity. As shown in 1014C, in the minute retreat movement of 1014A, the movement control unit 110 controls the vertical movement unit 16 at a velocity V bk Then, the object is slightly retracted in the direction of movement M1 for a certain period of time.

[0137] Next, as shown in 1014B, in step S22, the movement control unit 110 moves the vertical movement unit 16 that has performed the minute retreat movement in the movement direction M2 indicated by the arrow, which is the movement instruction direction D (upward).

[0138] As shown in 1014C, in the movement in the movement instruction direction D of 1014B, the movement control unit 110 controls the vertical moving unit 16 at a speed V fw1 Then, the robot moves in the direction M2, which is the movement instruction direction D, for a certain period of time. ... fw1 The specified velocity V fw2 and moves in the movement direction M2, which is the movement instruction direction D.

[0139] 14, as in FIG. 10, in either step S20 or step S22, the energy when the stylus 22 moves toward the workpiece W can be minimized, and damage to the workpiece W and the tip of the stylus 22 can be minimized, thereby contributing to an improvement in the life of the stylus 22 and the preservation of the workpiece W.

[0140] Although not described here, even when the measurement direction is upward, the vertical moving unit 16 can be moved by the movement control unit 110 in the same manner as in Figures 12 and 13. That is, the vertical moving unit 16 can be moved in the movement direction M1, which is the movement instruction direction D, without first moving the vertical moving unit 16 in the direction opposite to the movement instruction direction D.

[0141] Next, setting of the movement amount in the minute retraction movement will be described with reference to Fig. 15. Fig. 15 shows an example in which the surface shape of the inner surface of a hole formed in a workpiece W is measured.

[0142] As shown in 1015A, a hole H with an inner diameter D1 is formed in the workpiece W. A stylus 22 is attached to the tip of the arm 50, facing downward in the measurement direction.

[0143] It is preferable that the movement amount of the vertical moving part 16 during the minute retraction movement is set by the movement amount setting part 118 so that the stylus 22 located inside the hole H does not collide with the inner surface of the hole H on the side of the movement direction M1 when the vertical moving part 16 makes a minute retraction movement in the movement direction M1.

[0144] For example, the movement amount M D is the inner diameter of the hole D1 and the effective height of the stylus E HIt can be calculated from the difference using the following formula:

[0145] Travel amount M D <Inner diameter D1 - effective height of stylus E H Here, the effective height of the stylus E H is the sum of the height of the stylus 22 and the height of the arm 50.

[0146] As shown in 1015B, similar to 1015A, a hole H with an inner diameter D1 is formed in the workpiece W. Meanwhile, a stylus 22A facing downward in the measurement direction and a stylus 22B facing upward in the measurement direction are attached to the tip of the arm 50.

[0147] In 1015B, as in 1015A, the movement amount M D is the inner diameter of the hole D1 and the effective height of the stylus E H It can be calculated from the difference using the following formula:

[0148] Travel amount M D <Inner diameter D1 - effective height of stylus E H Here, the effective height of the stylus E H is the sum of the height of the stylus 22A, the height of the stylus 22B, and the height of the arm 50.

[0149] In Figure 15, the inner diameter D1 and the effective height E of the stylus H By inputting the above from the operation unit 24, the movement amount setting unit 118 determines the movement amount M D can be calculated and set. D is input from the operation unit 24, and the movement amount M D can be set.

[0150] The movement control unit 110 is controlled to move the object by the movement amount M set by the movement amount setting unit 118. D When making the minute retraction movement, the stylus 22 (22B) does not collide with the surface of the hole H in the direction of movement M1, so that the workpiece W and the stylus 22 can be more effectively protected.

[0151] Next, a surface profile measuring apparatus 10A according to another embodiment of the surface profile measuring apparatus 10 will be described with reference to FIG.

[0152] As shown in Figure 16, the surface shape measuring device 10A includes a flat base 12, a column 14, a vertical moving unit 16, a horizontal driving unit 18, a detector 20 equipped with a stylus 22, an operation unit 24, a monitor 26, a control device 30, and an inclination driving unit 60.

[0153] The surface profile measuring apparatus 10A differs from the surface profile measuring apparatus 10 in that it includes a tilt driving unit 60.

[0154] The tilt drive unit 60 rotates around a rotation axis 60A in a direction perpendicular to both the direction of movement of the vertical movement unit 16 and the direction of movement of the detector 20 by the horizontal drive unit 18.

[0155] The horizontal drive unit 18 is connected to the vertical movement unit 16 via the tilt drive unit 60, and the tilt drive unit 60 rotates around a rotation axis 60A, thereby tilting the detector 20 with respect to the workpiece W. This allows the stylus 22 provided in the detector 20 to tilt according to the tilt state of the surface of the workpiece W (surface to be measured).

[0156] The control device 30A has the same configuration as the control device 30, and further includes a rotation control unit 120 that controls the rotation of the tilt drive unit 60.

[0157] The rotation control unit 120 controls the rotation of the tilt drive unit 60 when it receives a rotation instruction from the control unit 100 or the like.

[0158] FIG. 17 is a diagram illustrating a case where the tilt driving unit 60 executes a slight retreat rotation movement in the direction opposite to the rotation instruction direction, and a rotation in the direction that matches the rotation instruction direction.

[0159] As shown in 1017A, the rotation control unit 120 rotates the tilt drive unit 60 in the rotation instruction direction R D and the direction in which the stylus 22 contacts the workpiece W coincide with each other, the rotation indicating direction RD The tilt drive unit 60 is rotated once in a rotation direction R1, which is the opposite direction to the rotation direction R1.

[0160] Next, as shown in 1017B, the rotation control unit 120 rotates the tilt driving unit 60 to slightly retreat in the rotation direction R1, and then rotates the tilt driving unit 60 in the rotation instruction direction R D The rotation is made in the direction R2.

[0161] Even when the detector 20 is rotated by the tilt drive unit 60, damage to the workpiece W and the tip of the stylus 22 can be minimized.

[0162] When the rotation instruction direction is opposite to the contact direction, the tilt drive unit 60 is rotated in the rotation instruction direction without making the slight retraction rotational movement.

[0163] The rotation control unit 120 can determine whether the rotation direction matches the contact direction based on the horizontal position of the detector 20, the type of the stylus 22, and the measurement direction of the detector.

[0164] <Effects of the embodiment> As described above, according to the surface profile measuring apparatus 10 (10A) of the embodiment, when a movement instruction to move the vertical moving unit 16 along the longitudinal direction of the column 14 is received, the movement control unit 110, based on the contact information acquired by the contact information acquisition unit 116 and the measurement direction information acquired by the measurement direction information acquisition unit 114, performs control to move the vertical moving unit 16 in the instructed direction by performing a small retraction movement to temporarily move the vertical moving unit 16 in the opposite direction to the instructed movement direction, and then moves the vertical moving unit 16 in the instructed movement direction, if the stylus 22 is in contact with the workpiece W and the instructed movement direction of the vertical moving unit 16 is the same as the measurement direction. This makes it possible to prevent effects (such as damage to the stylus 22 or the workpiece W) associated with the switch from static friction to kinetic friction when the vertical moving unit 16 starts to move.

[0165] Furthermore, according to the surface shape measuring apparatus 10 (10A) of the embodiment, when either the stylus 22 is not in contact with the workpiece W or the instructed movement direction of the vertical movement unit 16 is opposite to the measurement direction, the movement control unit 110 controls the vertical movement unit 16 to move in the instructed movement direction without first moving the vertical movement unit 16 in the direction opposite to the instructed movement direction. That is, in such a case, there is little or no effect associated with the switch from static friction to kinetic friction when the vertical movement unit 16 starts to move, so it is possible to efficiently change the relative position between the detector 20 (stylus 22) and the workpiece W by moving the vertical movement unit 16 in the instructed movement direction without performing a small retraction movement.

[0166] Furthermore, according to the surface profile measuring apparatus 10 (10A) of the embodiment, when executing a micro-retraction movement, the movement control unit 110 performs the micro-retraction movement while maintaining contact between the stylus 22 and the workpiece W. As a result, the micro-retraction movement is performed without separating the stylus 22 from the workpiece W, and therefore, when the vertical movement unit 16 is moved in the movement instruction direction after the micro-retraction movement, it is possible to avoid the stylus 22 colliding with the workpiece W from a position away from the workpiece W. As a result, it is possible to further prevent damage to the stylus 22 and the workpiece W.

[0167] Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the spirit of the present invention. Some modifications will be described below.

[0168] <Variation 1> In the above-described embodiment, when the stylus 22 is in contact with the workpiece W and the instructed direction of movement of the vertical moving unit 16 is the same as the measurement direction, the vertical moving unit 16 is controlled to temporarily move in a small retraction direction opposite to the instructed direction of movement, and then move in the instructed direction of movement. However, this control is not limited to this. For example, even when the stylus 22 is not in contact with the workpiece W, even when the instructed direction of movement of the vertical moving unit 16 is the same as the measurement direction, the vertical moving unit 16 may be controlled to temporarily move in a small retraction direction opposite to the instructed direction of movement, and then move in the instructed direction of movement. In other words, regardless of whether the stylus 22 is in contact with the workpiece W, whether to perform a small retraction may be determined depending on whether the instructed direction of movement of the vertical moving unit 16 is the same as the measurement direction.

[0169] <Variation 2> In the above-described embodiment, the movement control unit 110 controls the micro-retraction movement so that the micro-retraction movement is performed while maintaining contact between the stylus 22 and the workpiece W, but this control is not limited to this. For example, the micro-retraction movement may be performed until the contact between the stylus 22 and the workpiece W is released (non-contact state). Furthermore, depending on the thrust required to start moving the vertical moving unit 16 and the time the vertical moving unit 16 is stopped on the column 14, the micro-retraction movement may be selectively switched between performing the micro-retraction movement while maintaining contact between the stylus 22 and the workpiece W and performing the micro-retraction movement until the contact between the stylus 22 and the workpiece W is released (non-contact state).

[0170] <Variation 3> In the above-described embodiment, the contact information acquisition unit 116 acquires contact information indicating whether or not the stylus 22 is in contact with the surface of the workpiece W based on information from the displacement detection unit 56 of the detector 20, but the manner in which the contact information is acquired is not limited to this. For example, a camera may be attached to a position (such as the base 12, the detector 20, or the horizontal drive unit 18) from which the measurement position (contact position of the stylus 22) on the surface of the workpiece W can be observed, and the contact information may be acquired based on image information captured by the camera. Alternatively, the user may directly observe the contact state of the stylus 22 with the surface of the workpiece W. In this case, the contact information acquisition unit 116 acquires the user's observation results (the contact state of the stylus 22 with the surface of the workpiece W) input to the input unit 104 from the operation unit 24. [Explanation of symbols]

[0171] 10...Surface shape measuring device, 10A...Surface shape measuring device, 12...Base, 14...Column, 16...Vertical moving part, 18...Horizontal driving part, 20...Detector, 22...Sensor, 22A...Sensor, 22B...Sensor, 24...Operation part, 26...Monitor, 30...Control device, 30A...Control device, 40...Rail, 42...Slider, 46...Motor, 48...X position detection mechanism, 50...Arm, 50A...Arm tip, 50B...Arm base, 52...Swing fulcrum, 54...Measuring force imparting mechanism, 5 6...Displacement detection unit, 60...Tilt drive unit, 60A...Rotation axis, 64...Motor, 66...Z position detection mechanism, 70...Column insertion hole, 72...Nut, 74...Sliding material, 76...Pressure mechanism, 100...Control unit, 102...Memory unit, 104...Input unit, 106...Display control unit, 108...Detection data acquisition unit, 110...Movement control unit, 112...Measuring force application control unit, 114...Measurement direction information acquisition unit, 116...Contact information acquisition unit, 118...Movement amount setting unit, 120...Rotation control unit, W...Workpiece

Claims

1. a detector that detects the displacement of a stylus that comes into contact with the surface of the measurement object; a moving unit that holds the detector and is movable in a direction in which the stylus approaches and moves away from the surface of the object to be measured; a control unit that, when the moving unit starts moving from a stopped state toward an approaching side in which the stylus approaches the surface of the object to be measured in the approaching and separating directions, retracts the moving unit toward a separating side in which the stylus moves away from the surface of the object to be measured, and then moves the moving unit toward the approaching side; A surface shape measuring apparatus comprising:

2. a detection unit that detects a contact state between the surface of the measurement object and the stylus, When the detection unit detects the contact state, the control unit moves the moving unit to the approaching side after retreating, and when the detection unit does not detect the contact state, moves the moving unit to the approaching side without retreating. The surface shape measuring apparatus according to claim 1 .

3. A control method for a surface profile measuring instrument including: a detector that detects displacement of a stylus that contacts a surface of a measurement object; and a moving unit that holds the detector and is movable in a direction in which the stylus approaches and moves away from the surface of the measurement object, comprising: a control step of, when the moving unit starts moving from a stopped state toward the approaching side in the approaching and separating directions in which the stylus approaches the surface of the object to be measured, retracting the moving unit toward the separating side in which the stylus moves away from the surface of the object to be measured, and then moving the moving unit toward the approaching side, A method for controlling a surface shape measuring device.

4. a detection step of detecting a contact state between the surface of the measurement object and the stylus, In the control step, when the contact state is detected in the detection step, the moving unit is retracted and moved to the separating side and then moved to the approaching side, and when the contact state is not detected in the detection step, the moving unit is moved to the approaching side without being retracted and moved to the separating side. A method for controlling the surface shape measuring apparatus according to claim 3.

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