JP3099645B2 - Articulated 3D measuring machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an articulated three-dimensional measuring device for measuring the shape and position of an object placed in a three-dimensional space.

[0002]

2. Description of the Related Art Conventionally, in order to measure the shape and position of an object placed in a three-dimensional space, a multi-joint type three-dimensional measuring machine for obtaining a three-dimensional position of a specific point of an object to be measured. It has been known. This type of multi-joint type three-dimensional measuring machine generally connects the arms by a joint mechanism having two degrees of freedom, attaches an angle detector to the rotation axis of the joint to measure the amount of rotation, and has a maximum of three joints and six degrees of freedom. A multi-joint measurement arm mechanism having a degree is configured. Then, spherical and conical contacts are attached to the tip of the measurement arm mechanism, and the three-dimensional position of the contact point with the contact, or a laser displacement meter is attached to the tip of the measurement arm mechanism, and the laser displacement is set. The three-dimensional position of the point indicated by the meter is calculated and obtained from the values of the respective arm lengths and the angle detector attached to the joint.

[0003]

However, in the operation of measuring with this type of measuring instrument, the measuring operator is holding the tip of the measuring arm mechanism and supporting the weight of the arm. There was a problem that the measuring work at the measuring point became bitter work by bending the waist while supporting the weight of the measuring arm. In addition, since each joint of the measurement arm mechanism moves freely, as soon as the worker releases his / her hand from the measurement arm mechanism, the tip of the measurement arm hangs down due to its own weight, and the measurement elements such as the contact element and the laser displacement gauge are measured on the ground or the measurement object. There was a danger of colliding with the machine base, etc., so care was required in handling.

Further, in the articulated three-dimensional measuring machine, since the measuring range is limited by the length of the measuring arm mechanism, the measuring machine needs to be moved to measure a larger range.
The leveling work of the measuring instrument must be performed every time it moves. In this leveling work, the operator adjusts the height of the measuring machine base height adjusting feet by hand while observing two spirit levels attached to the measuring machine base in directions perpendicular to each other. Was a time-consuming task.

It is an object of the present invention to provide a multi-joint type three-dimensional measuring machine capable of reducing a burden on a measuring operation and reducing a leveling operation time.

[0006]

In order to achieve the above object, a multi-joint type three-dimensional measuring device according to the present invention is provided with a three-dimensionally movable measuring element attached to a base via an articulated arm mechanism. In a three-dimensional measuring machine that outputs a three-dimensional position of a point indicated by the measuring element, a support is erected on the base so as to be pivotable, and an extendable horizontal arm is attached to the support. , A balancer is attached, and the measuring element or an arm provided with the same is suspended and held through the balancer.

In addition to the above configuration, two inclinometers are installed on axes perpendicular to each other on the measurement base surface and a lifting mechanism such as a jack is provided on the measuring machine base in order to shorten the leveling operation time. When the measuring instrument is installed in a state where it is tilted beyond the measuring range of the inclinometer, it refers to only the sign of the output signal of the inclinometer, detects the inclination of the measuring instrument, and operates a jack or other elevator to operate the measuring instrument. Can be configured to detect the amount of inclination of the three-dimensional coordinates with high accuracy and correct the measured three-dimensional coordinate values.

[0008]

According to the above arrangement, the measurement arm mechanism is suspended via a suspending means such as a wire instead of the operator, but this is supported via the balancer, so that the burden on the measurement operator can be reduced. it can. When a wire is used as the suspending means, it is premised that the wire drawn from the balancer vertically moves up and down, and if the wire is inclined obliquely beyond an allowable angle, it may not operate. For this purpose, it is only necessary that the balancer moves following the position movement of the measuring arm mechanism moving in an arbitrary direction, and that the connecting means such as a wire drawn from the balancer be always maintained in a vertical state. Therefore, by fixing the balancer to the tip of the horizontal arm that expands and contracts in the horizontal direction above the measurement arm mechanism, the balancer can follow the forward and backward movement of the tip of the measurement arm mechanism. Further, since the telescopic horizontal arm is mounted on a vertical support provided with a rotation guide mechanism and can be horizontally turned, it can follow the left and right movement of the tip of the measurement arm mechanism. In this case, the support standing on the base can be integrally attached to the side surface of the main shaft of the measurement arm mechanism that stands vertically from the base of the measuring instrument. In this way, the spindle rotation guide mechanism of the measurement arm mechanism can be used, and no special rotation mechanism is required. The column rotates about the main axis, which can be absorbed by the expansion and contraction of the horizontal arm.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the articulated three-dimensional measuring machine according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a side view showing the configuration of an articulated three-dimensional measuring machine according to an embodiment. As shown in the figure, this articulated three-dimensional measuring machine has a base 10 also serving as a cart, and an arm spindle 12 is erected on the base 10. The mechanism 14 is attached. As shown, the articulated arm mechanism 14 includes a first arm 18 connected to an upper end of the arm main shaft 12 by a joint 16 having two degrees of freedom so that the base end can rotate and swing. The proximal end of the second arm 22 is connected to the distal end of the first arm 16 by a joint 20 having two degrees of freedom. Further, a probe arm 26 connected via a joint 24 having two degrees of freedom is attached to the distal end of the second arm 22. Therefore, the multi-joint measurement arm mechanism 14 has a maximum of 3 joints, 6 joints.
The structure has a degree of freedom. In addition, each joint 16,
An angle detector for measuring the amount of rotation is attached to the rotation shafts 20 and 24 so that the arm bending angle can be detected.

A spherical and conical contact 28 is attached to the tip of the measuring arm 26, and the three-dimensional position of the contact with the contact 28 is determined by the length of each arm and the angle attached to the joint. It is configured to calculate and obtain from the value of the detector. Instead of the contact 28, a laser displacement meter is attached to the tip of the measurement arm 26, and the three-dimensional position of the point indicated by the laser displacement meter is calculated from each arm length and the value of the angle detector attached to the joint. It can be configured as required.

In addition to such a basic configuration, in the articulated three-dimensional measuring machine according to the present embodiment, the contact 28 or the arm mechanism to which the contact 28 is attached is suspended and supported while being balanced in weight. Make up. That is, a support 30 is integrally attached to a side portion of the arm main shaft 12, particularly to a shaft portion for rotating the articulated arm mechanism 14 so as not to interfere with the operation of the arm mechanism 14. I have. Thus, the column 30 is turned around the main shaft 12 with the rotation of the arm mechanism 14.

The turning column 30 is set sufficiently higher than the height of the arm main shaft 12, and a horizontal arm 32 is attached to an upper end portion thereof. The horizontal arm 32 is attached via a rotation mechanism (not shown) so as to be rotatable around the axis of the column 30, and is horizontally rotatable about the column 30. The horizontal arm 32 has a telescopic structure, and can be easily expanded and contracted by a guide having a built-in tip arm portion 32a. The guide can be formed by a roller mechanism or a slider mechanism. A balancer 34 is attached to the protruding end of the tip arm 32a, and the second arm 22 on the contact 28 side of the articulated arm mechanism 14 is suspended and supported via the balancer 34.

First, means for suspending the second arm 22
In the embodiment, the balancer 3 is formed by a wire.
4 and a support wire 40 fastened to two points at the distal end and the proximal end of the second arm 22.
The support wire 40 is suspended by winding it around the pulley 36. Thus, even if the second arm 22 is tilted, the movement of the support wire 40 due to the tilt is absorbed by the pulley 36 and does not affect the payout wire 38 side.

The weight of the arm mechanism 14 suspended by the wires 38 and 40 is transmitted to the balancer 34. The balancer 34 applies a lifting balance force in the opposite direction equivalent to the weight of the arm mechanism 14 applied thereto. Thereby, the measuring element arm 26 and the tip contact 28 of the arm mechanism 14 can be three-dimensionally moved without load. A well-known balancer may be used. For example, the feed wire 3 by the spring force
The winding reel of No. 8 may be biased so as to rotate in the winding direction, and a reel configured to adjust the winding spring force in accordance with the suspension force may be used.

Further, in this embodiment, the following construction is made so that the horizontal level of the base 10 can be easily obtained. For leveling, two inclinometers 42 are provided on the ground surface of the measuring machine base 10 along axes orthogonal to each other. On the other hand, three jacks 44 are built in the measuring instrument base 10 as an elevating mechanism, and are arranged so that the base 10 can be horizontally adjusted by projecting from the lower surface. Further, a pulse motor 46 for driving such jacks 44 is provided so that each jack 44 can be driven and adjusted to an arbitrary height. Control means (not shown) is provided for level adjustment. The control means receives tilt signals from the two inclinometers 42 (42x, 42y), and rotates around each axis according to the detected tilt angle of each inclinometer. A drive signal to the pulse motor 46 is output so as to perform the driving.

This specific leveling control method will be described with reference to FIG. First, the output voltage of the two-axis inclinometer 42 is read (step 100), and it is determined whether or not this output value is within the measurement range (step 102). The inclination direction is detected (step 104), and the jack 44 on the lower side is raised by a fixed amount (step 106).
Return to 00. That is, when the tilt amount exceeds the measurement range, the tilt is quickly corrected by uniformly raising the jack on the lower side by a fixed amount. If the output of the inclinometer is within the measurement range in step 102, an angle calculation process is performed (step 108), and the calculation result is compared with the target angle to determine whether the output is within the leveling target angle. (Step 110). If it is out of the range, a deviation is obtained and a jack driving amount corresponding to the deviation is calculated (step 112).
The lowering jack 44 is driven according to the calculated value (step 114), the output voltage of the biaxial inclinometer 42 is read again (step 116), and the loop returning to the angle calculation processing step 108 is repeated. , The level reaches the target allowable value, and the processing ends. As a result, the horizontal leveling process is performed very quickly.

The operation of the multi-joint type three-dimensional measuring machine having the above-described structure is as follows. First, in the examples, a measuring machine having a measurement accuracy of ± 0.3 mm was used as an articulated three-dimensional measuring machine. The second arm 22 of the arm mechanism 14 is supported by a balancer 34 via a two-point support wire 40. Since the arm's own weight is supported by the balancer 34 via the wire 38, the operator does not need to be aware of the arm's own weight and the contact 28
Can be moved to any position. Further, even if the operator releases his / her hand from the arm, the arm is maintained at the current height by the balancer 34. The balancer 34 is fixed to the distal end of an arm 32 that extends and contracts in the horizontal direction, which is located above the arm mechanism 14, and since the extendable arm 32 is attached to the vertical support 30 provided with a rotation guide mechanism,
Is moved in an arbitrary direction, the payout wire 38 of the balancer 34 is always kept in a vertical state.

The arm main shaft 12 and the vertical support 30 and the vertical support 30 and the telescopic horizontal arm 32 are fastened by bolts so that they can be disassembled during transportation.

A method of correcting the three-dimensional coordinate value based on the value of the inclinometer 42 will be described below. Two inclinometers 42x, 4
Assuming that the orthogonal axis where 2y is installed is the X axis and the Y axis, respectively, for convenience, the measuring instrument is an inclinometer 42x installed in parallel with the X axis direction.
Is rotated about the Y axis by an angle ω indicated by X, and further X is shifted by an angle φ indicated by an inclinometer 42y installed in parallel with the Y axis direction.
It is considered to be in a state of rotational movement around the axis. The three-dimensional coordinate value measured by the measuring instrument in a tilted state after receiving the rotational movement is subjected to reverse rotational movement of the rotational movement. That is, by performing a rotational movement by −φ around the X-axis and then performing a rotational movement by −ω around the Y-axis, the three-dimensional coordinate value measured by a horizontally installed measuring instrument becomes equivalent.
Therefore, the control means refers to only the sign of the output signal of the inclinometer 42, detects the inclination direction of the measuring instrument, and
An elevator such as the one described above is operated by the pulse motor 46 to adjust the level of the base 10 within the inclinometer measurement range. Then, with the horizontality of the base 10 adjusted in this way, the inclination of the articulated three-dimensional measuring machine is detected from the output value of the inclinometer 42, and the measured three-dimensional coordinate values are corrected. Good. In order to confirm the effect of this method, measurement on the level surface plate was carried out, and the variation in coordinate values corrected by the inclinometer value was examined to be within ± 0.3 mm. confirmed.

A measuring instrument was installed on the floor inclined at 8 degrees,
When the leveling operation was actually performed, it took 5 minutes for the conventional manual leveling operation, but the leveling was completed in 1 minute in the method according to the present embodiment.

[0022]

According to the present invention, there is provided a three-dimensional measuring machine for attaching a measuring element to a base via a multi-joint arm mechanism so as to be movable three-dimensionally and outputting a three-dimensional position of a designated point by the measuring element. A pillar is erected on the base so that it can swivel, an extendable horizontal arm is attached to this pillar, and a balancer is attached to the tip of this horizontal arm,
Since the measuring element or the arm provided with the measuring element is suspended and held via this balancer, the measuring operator can perform measurement without supporting the arm's own weight, and in the leveling operation, the working time can be reduced. Excellent effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of an articulated three-dimensional measuring machine according to an embodiment.

FIG. 2 is a flowchart of an automatic leveling process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Measuring machine base 12 Arm spindle 14 Articulated arm mechanism 16, 20, 24 2 degrees of freedom joint 18 1st arm 22 2nd arm 24 Measuring arm 28 Contact 30 Strut 32 Horizontal arm 34 Balancer 36 Pulley 38 Feeding wire 40 Support Wire 42 inclinometer 44 jack 46 pulse motor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01B 21/00-21/32 B25J 1/00-1/12 B25J 5/00-9/08 B25J 11 / 00 B25J 17/00-19/00 B25J 21/00-21/02

Claims (1)

(57) [Claims] 1. A three-dimensional measuring device for attaching a measuring element to a base via a multi-joint arm mechanism so as to be movable three-dimensionally and outputting a three-dimensional position of a designated point by the measuring element. An extendable horizontal arm is attached to this support, and a balancer is attached to the tip of the horizontal arm, and the measuring element or an arm having the same is suspended and held through this balancer. An articulated three-dimensional measuring machine characterized by the following.