CN2591559Y - Contacting potetial attitude measuring apparatus - Google Patents

Abstract

The utility model belongs to a precision automatic measuring device, in particular to a robot arm, a six-dimensional wrist force sensor and an elastic probe to detect the geometric shape of the surface of a workpiece or the pose of an object. This measurement device replaces the traditional binocular vision detection method. Its technical solution is: to obtain the ideal coordinates of the points on the object in the tool coordinate system through the force information of the contact point between the probe and the object surface, and then through the robot kinematics by The coordinates of the point in the robot's base coordinate system are obtained by coordinate transformation, and then the movement of the end of the robot is controlled by the information of the six-dimensional wrist force sensor, so that the probe is in good contact with the measured surface and moves, and the positions of a series of points on the surface of the object are measured Coordinate information, so as to determine the pose or surface geometry of the object in the robot's base coordinate system. It is also possible to observe the surface information of the object with the help of a single camera, and then use the probe to measure the position information of the feature points on the object surface, so that the geometric shape of the measured surface can be quickly generated or the pose of the object can be measured. The method for measuring the geometric shape of the surface of the workpiece or detecting the position and posture of the object is simple and easy, with small calculation amount and high precision.

Description

Contact object pose measurement device

technical field

The utility model relates to a system for detecting the position and posture of an object by means of a robot, a six-dimensional wrist force sensor, an elastic probe and a computer and a realization method thereof. It involves robotics, mechanics of materials, computers and other disciplines.

Background technique

Robot technology is widely used in industrial fields, such as automatic assembly, automatic welding, painting, inspection and measurement of mechanical parts, etc. In these applications, the measurement of workpieces with complex curved surfaces and the detection of object poses are important prerequisites for automatic operations. Existing measurement and detection methods are generally implemented using binocular vision, but this method requires a huge amount of data to be processed, and the image matching algorithm in binocular vision is not perfect, and the error is relatively large.

Utility model content

In order to overcome the shortcomings of the above methods, the utility model proposes a new method for object pose detection or curved surface measurement. By controlling the movement of the robot arm, the elastic probe installed at the end of the arm can be in good contact with the surface to be tested. It only needs to collect the contact force information of the wrist force sensor, and according to the mapping relationship between the force and deformation of the elastic probe, the data is processed by the computer. Processing, the measurement of the workpiece surface and the detection of the object pose can be realized. The content includes: (1) An object pose detection system composed of a robot, a six-dimensional wrist force sensor, an elastic probe and a computer. (2) The combination of the six-dimensional wrist force sensor and the elastic probe is proposed, and the algorithm of determining the geometric shape of the workpiece surface or the object pose is determined by using the information of the six-dimensional wrist force sensor, and the corresponding processing software is designed.

The technical solution adopted by the utility model to solve the technical problems is: a contact-type object posture measurement device, which is composed of a robot, a sensor, a probe, and a computer. The six-dimensional wrist force sensor is installed at the end of the robot arm, and the elastic probe is installed. On the six-dimensional wrist force sensor, the six-dimensional wrist force sensor is connected with the force information acquisition card in the computer by a data line, and the robot is connected with the computer by a control bus.

The measuring device consists of a six-dimensional wrist force sensor and an elastic probe to form an information collection unit required for object pose detection or curved surface measurement.

The measurement device described above only needs to collect the six-dimensional contact force information of the wrist force sensor to detect the pose or curved surface shape of the object, and obtain the contact position between the end of the probe and the surface of the object from the mapping relationship between the six-dimensional contact force and the deformation of the probe. The position in the tool coordinate system, and then the spatial position information of the detection point on the object in the robot base coordinate system is obtained through coordinate transformation.

The measuring device obtains the position and posture of the measured object or the geometric shape of the surface by detecting the position coordinates of a series of points on the surface of the object.

In the measuring device, a CCD camera can be installed in parallel on the wrist of the robot to obtain the surface information of the measured object, and the depth information of the characteristic points obtained by the probe can improve the detection efficiency.

In the measuring device, the probe is a three-dimensional elastic rigid material, which is in flexible contact with the surface of the measured object. The robot arm controls the probe to make good contact with the surface to be tested and moves according to the six-dimensional contact force information of the wrist force sensor to realize automatic detection.

The measuring device can measure the surface shape of objects mainly with curved surfaces.

As shown in FIG. 1 , the six-dimensional wrist force sensor 1 and the elastic probe 2 are fixed on the wrist and end of the robot 5 in sequence. The six-dimensional wrist force sensor 1 collects the contact force information between the probe and the measured object 3, and transmits it to the computer 6 through the data line 7. Through the processing of the force information, as shown in Figure 2, the elastic deformation of the probe end can be obtained , so that the coordinates of a point P on the object in the tool coordinate system OXYZ can be determined, and the coordinates can be finally transformed into the robot's base coordinate system through the kinematics of the manipulator. In order to improve the detection speed, it is generally possible to observe with the help of a camera installed on the macro site or the wrist, and only need to measure the position information of the feature points on the surface of the object with the probe to obtain the attitude of the object in the robot base coordinate system or obtain the position of its surface. geometry.

The location of a spatial point generally requires two images, which are determined by the intersection of two projection lines. However, the method proposed by the utility model can use the force information of the probe contact to determine the position of the space point.

Compared with binocular vision, the utility model fundamentally avoids uncertainty and error caused by image matching. After the force of the contact is determined, its coordinates in the tool coordinate system can be obtained by simple calculation. The binocular vision requires image matching first, and then finds the intersection of the projection lines. Obviously, the utility model greatly reduces the calculation amount and improves the detection speed. Compared with other measurement and detection methods, the utility model is simpler and more practical.

Description of drawings

Figure 1: Structural diagram of the object pose measurement system

Figure 2: Schematic description of the detection of the deformation caused by the contact of the elastic probe with the measured object

Detailed ways

As shown in FIG. 1 , the six-dimensional wrist force sensor 1 and the elastic probe 2 are sequentially fixed on the wrist of the robot 5 and the end of the six-dimensional wrist force sensor 1 . The measured object 3 is placed on the workbench 4, and the six-dimensional wrist force sensor 1 collects the information of the contact force between the probe and the measured object 3, and transmits it to the computer 6 through the data line 7. Through the processing of the force information, the probe can be obtained. The force on the needle in the directions of x, y, and z axes, and the moment around the three axes. as shown in picture 2, AO is the position where the probe is not deformed, and AB is the position where the probe is deformed during actual measurement. According to the physical characteristics of the probe, the elastic deformation Δx, Δy, Δz of the probe end along the three axes, and the angles α, β, γ between the tangent line of the probe end and the three coordinate axes can be obtained, so that the position on the object can be determined The coordinates of a point P in the tool coordinate system OXYZ, which can be finally converted to the base coordinate system of the robot through the kinematics of the manipulator. In order to improve the detection speed, it is generally possible to observe with the help of a camera installed on the macro site or the wrist, and only need to measure the position information of the feature points on the surface of the object with the probe to obtain the attitude of the object in the robot base coordinate system or obtain the position of its surface. geometry.

The utility model belongs to a precision automatic measuring device, in particular to a robot arm, a six-dimensional wrist force sensor and an elastic probe to detect the geometric shape of the workpiece surface or the pose of an object. This measurement device replaces the traditional binocular vision detection method. Its technical solution is: to obtain the ideal coordinates of the points on the object in the tool coordinate system through the force information of the contact point between the probe and the object surface, and then through the robot kinematics by The coordinates of the point in the robot's base coordinate system are obtained by coordinate transformation, and then the movement of the end of the robot is controlled by the information of the six-dimensional wrist force sensor, so that the probe is in good contact with the surface to be measured and moves, and the positions of a series of points on the surface of the object are measured Coordinate information, so as to determine the pose or surface geometry of the object in the robot's base coordinate system. It is also possible to observe the surface information of the object with the help of a single camera, and then use the probe to measure the position information of the feature points on the object surface, so that the geometric shape of the measured surface can be quickly generated or the pose of the object can be measured. The method for measuring the geometric shape of the surface of the workpiece or detecting the position and posture of the object is simple and easy, with small calculation amount and high precision.

Claims (7)

1. contact type object pose measuring apparatus, form by robot, sensor, probe, computing machine, it is characterized in that: sextuple wrist force sensor (1) is installed in the end of robot (5) arm, elastic probe (2) is installed on the sextuple wrist force sensor (1), sextuple wrist force sensor (1) is linked to each other with force information capture card in the computing machine (6) by data line (7), and robot (5) is linked to each other with computing machine (6) by control bus (8).

2. measurement mechanism according to claim 1 is characterized in that: detected or the required information acquisition unit of measurement of curved surface by a sextuple wrist force sensor (1) and an elastic probe (2) constituent posture.

3. measurement mechanism according to claim 1, it is characterized in that: the pose of inspected object or curve form only need be gathered the sextuple contact force information of wrist force sensor, obtain the position of contact in tool coordinates system on probe end and the body surface by the mapping relations of sextuple contact force and probe deformations, and then obtain the spatial positional information of check point in basis coordinates system of robot on the object by coordinate transform.

4. according to claim 1,3 described measurement mechanisms, it is characterized in that:, obtain the pose of testee or the geometric configuration on surface by the position coordinates that detects the body surface series of points that obtains.

5. measurement mechanism according to claim 1 is characterized in that: can obtain the testee surface information at CCD gamma camera of the parallel installation of robot wrist, the depth information of adding the resulting unique point of probe can improve the efficient of detection.

6. measurement mechanism according to claim 1 is characterized in that: probe is the three dimensional elasticity rigid material, contacts with the testee surface flexible.Well contact with measured surface and move according to the sextuple contact force information control probe of wrist force sensor by the robots arm, realize detecting automatically.

7. measurement mechanism according to claim 1 is characterized in that: can measure the object surfaces shape based on curved surface.