JPS62229008A - Automatic measuring method for positional deviation and angle of attitude of object with line sensor - Google Patents

Abstract

PURPOSE:To enable accurate measurement of positional deviations and the angle of attitude, by arranging first-third line sensors in the manner that they are orthogonal to one side at the midpoint with respect to another side of a rectangular object, located at a reference position, and to compute deviations therebetween based on outputs of the line sensors. CONSTITUTION:In a measuring area where positional deviations and an angle of attitude of an object A are measured, first and second line sensors 1 and 2 are arranged to the orthogonal to one side (straight line l) of a rectangular object A0, located at a reference position, at the midpoint thereof and a third line sensor 3 to be orthogonal to another side (straight line m) perpendicular to the said side of the object A0 at the midpoint thereof. In order to measure the positional deviations and the angle of attitude, crossing positions of the two sides of the object A, namely, the straight lines l and m and these line sensors are detected with the line sensors 1-3 to measure the deviations DELTAy1, DELTAy2 and DELTAx1 between the resulting positions and the reference position on the line sensors. In this manner, measured values are computed with an arithmetic unit to permit the determination of positional deviations DELTAx and DELTAy in the x and y axes of the object A and the angle theta of attitude with respect to a reference attitude.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for assembling parts in production lines for automobiles and home appliances, etc., by determining the position of objects, particularly objects having a substantially rectangular shape. and a method for automatically measuring posture.

[Prior Art] Various types of pattern recognition techniques have been developed to automate work on production lines. Such pattern recognition technology attempts to determine the shape, posture, etc. of the object itself by some means, and the equipment used for pattern recognition is usually relatively complex and expensive. It is.

However, the pattern recognition technology described above is not necessarily required when automating the assembly work in various factories, for example, the assembly of various parts to the body of an automobile or the body of a home appliance. In other words, the objects of recognition, such as automobile bodies, the main bodies of home appliances, IC boards, etc., usually have a substantially rectangular shape, and even if the recognition objects themselves are not rectangular, they may be rectangular. Or put it on a trolley and move it.

In many cases, a rectangular portion exists on the object, and the shape of the object to be recognized is usually known. Therefore, it is sufficient to accurately recognize the positional deviation and attitude of the substantially rectangular part, that is, the positional deviation and the inclination of the attitude angle with respect to the reference position of the rectangular part, and this greatly simplifies the device itself. , can be provided at low cost.

[Problems to be Solved by the Invention] In order to recognize a rectangular object, the present inventors discovered that
Based on the viewpoint that line sensors can be used without using the two-dimensional image of the object, etc., we investigated a method for easily measuring positional deviation and orientation using as few line sensors as possible, and accomplished the present invention. This is what led to this.

That is, an object of the present invention is to focus on the fact that objects to be recognized are substantially rectangular in many cases, and to utilize general pattern recognition technology in the above-mentioned assembly work at a factory. The object of the present invention is to make it possible to easily, inexpensively, and accurately measure positional deviations and attitude angles by a simple means of using a plurality of line sensors.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a rectangular shape at a reference position is included in a measurement area for measuring the positional deviation and attitude angle of a substantially rectangular object. The first and second line sensors are perpendicular to one side of the object at the midpoint,
A third line sensor is arranged at regular intervals and perpendicular to the other side which is perpendicular to one side of the object, and these line sensors measure the object in the measurement area and each line. It detects the intersection position with the sensor, measures the amount of positional deviation between the center point on each line sensor, and calculates the positional deviation and attitude angle of the object by calculating based on the amount of deviation. Employing technical means.

[Example] The method of the present invention will be explained in more detail below with reference to the drawings.

As shown in Fig. 81, in the space where the positional deviation and attitude angle measurement target A exists, the target A at the reference position is
Set an xy coordinate system with the origin O at the center of O. The object to be measured A has a substantially rectangular shape, and may be, for example, an automobile body viewed from above, an IC board, or the like. Furthermore, if the object to be measured is not rectangular, a rectangular part attached to it or a rectangular table on which the object is placed may be used as the measurement object A. In the figure, the corners of the object AO at the reference position are Pl, P2IP3 and P
4, and the corner of object A that takes an arbitrary posture is p;, p;,
p; and Pi, and each side of the measurement object A is
Indicated by mu, m, n and p.

Note that here, it is assumed that the shape of the object A itself is known, and in particular, the ffAW and length H of the object A are known.

The measurement area for measuring the positional deviation and attitude angle of the object A includes first and second line sensors 1, which are perpendicular to one side (straight line) of the rectangular object AO at the reference position at the midpoint; 2, and a third line sensor 3 that is perpendicular to the other side (direction Vjm) perpendicular to one side of the object AO at the midpoint. Then, the distance between these line sensors 1, 2.3 from the y-axis and the X-axis is
Lxl respectively.

Lx2. When arranging the line sensor as Ly+, each side of the object AO at the reference position does not necessarily need to be exactly orthogonal at the midpoint of the line sensor.

When the object A is transported by a belt conveyor or the like and reaches the measurement area, it usually has an arbitrary amount of positional deviation and an arbitrary amount of attitude angle inclination with respect to the reference position, as shown in Fig. 1. . That is, the center of the object A has a positional shift of ΔX and Δy in the X-axis and y-axis directions, respectively, with respect to the origin 0 of the coordinate system, and is also tilted by an angle θ with respect to the reference posture of the object. .

Therefore, in order to measure the positional deviation and attitude angle, the line sensors 1, 2.3 measure the two sides of the object A, that is, the straight line 1. Detect the intersection position with m and determine the base position (midpoint) on those line sensors.
The positional deviation amounts ΔYl, Δy2, and Δ! Measure 1.

In this way, the amount of deviation ΔY+, Δ
Te2 and Δ! 1, the calculation device performs calculations as described below to determine the positional deviation ΔX of the object A in the X-axis and y-axis directions.

Δy and the attitude angle θ relative to the reference attitude can be determined.

First, x′-y with the center of the object A as the origin
Once the 'coordinate system is set, coordinate transformation between the xy coordinate system and the xy coordinate system can be performed using the following transformation formula.

x'=xcosθ-y 5ino+ΔXy'=xsi
nθ+yCosθ+Δy Then, based on the above conversion formula, corner portions pi, p of the object Ao at the reference position? The coordinates of the corner pH, p of the object A whose position is shifted with respect to is expressed by.

Therefore, the equation for the straight line sentence is as follows, and the coordinates of the intersection with the line line on line sensors 1 and 2 are as follows.If these values are substituted into the equation for the line line above, Δy+ and Δy2 are expressed as follows: is given by

Similarly, the equation of the straight line m is as follows, and the coordinates of the point of intersection with the straight line am on the line sensor 3 are as follows. Therefore, Δ11 is given by the following equation.

Then, from the above equation (+) (2) −
--(3)Δy2−Δy+= (LX2+ Lit)−
θ can be obtained as tanθ, and the above (1
) Calculating ΔX and Δy from equation (3), we get Good a, ---(
5) Therefore, by performing the above-mentioned calculations with the calculation device connected to the line sensors 1, 2.3, the positional deviations ΔX and Δy of the object A in the X-axis and y-axis directions, and the attitude angle θ with respect to the reference attitude are calculated. can be found.

[Effects of the Invention] According to the measuring method of the present invention, the positional deviation and attitude angle of the object can be easily calculated by calculating the above-mentioned formula based on the outputs of the three line sensors. can be measured inexpensively and accurately.

In addition, since measurement can be carried out in a simple manner, it is not only easy to convert the equipment for processing the output from the line sensor into hardware, but also enables real-time processing, which improves factory production. It is extremely suitable for use in lines, etc.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the measurement method according to the present invention. 1.2.3 - Fist line sensor, A...Target.

Claims (1)

[Claims] 1. First and second lines perpendicular to one side of the rectangular object at the reference position at the midpoint in the measurement area for measuring the positional deviation and attitude angle of the substantially rectangular object. The sensors are arranged at regular intervals, and a third line sensor is arranged at a midpoint perpendicular to another side perpendicular to one side of the object, and these line sensors measure the object in the measurement area. Detect the intersection position between the line sensor and each line sensor, measure the amount of positional deviation between the center point on each line sensor, and calculate the positional deviation and attitude angle of the object by calculating based on the amount of deviation. A method for automatically measuring positional deviation and attitude angle of an object using a line sensor.