In the robot flexibility vision measurement system, tool coordinates is fast repairing method
Technical field
The invention belongs to that in the robot flexibility vision measurement system, tool coordinates is calibration steps, particularly a kind of tool coordinates based on reference sphere is quick prosthetic appliance and method.
Background technology
The robot tool coordinate system is defined on robot end's joint coordinate system basis, and it can be used for representing that it is moving of change in coordinate axis direction along tool coordinates that robot produces.In the flexible vision measurement system of industrial robot, generally adopt the teach programming mode, by suitable measurement track of teaching, utilize the high characteristics of robot repetitive positioning accuracy, can realize the vision on-line measurement.Robot teaching programming is normally based on tool coordinates system and tool center point (TCP) and complete specific work.In flexible vision on-line measurement system, traditional robot teaching programming with robot end's coordinate system as tool coordinates is, with robot end's flange center's point as TCP.In measuring process, robot moves to TCP the position of recording in the teaching track exactly, and the direction that records when tool coordinates is direction and teaching alignment.
In industrial processes, because robot crashes or the reason such as instrument maintenance, often need to change vision sensor or mechanical adaptor.Because the structure of vision sensor there are differences, the machining precision of machinery adaptor is different with installation accuracy, structured light sensor projects optical plane locus will change, and the spatial relation of sensor coordinate system and robot end's wrist coordinate system also will change.If robot still according to the trajectory measurement of original teaching, can't the resetting of implementation structure optical sensor arrive measuring position before, directly affect measuring accuracy, even because striation departs from too much, the mathematical model that causes setting up can't realize measuring.Traditional solution be after repairing mechanical adaptor again the teaching robot measure track, this mode not only wastes time and energy, and work difficulty is large.The fast repairing method of tool coordinates system can be created larger economic benefit and social benefit.
Summary of the invention
The object of the invention is to overcome the above-mentioned deficiency of prior art, a kind of robot tool coordinate system and TCP fast repairing method are provided, can save time and the labour when guaranteeing security, can satisfy in the robot flexibility vision detection system the on-the-spot robot rear application demand of resuming production fast and measuring that crashes simultaneously.Technical scheme of the present invention is as follows:
The invention provides a kind of tool coordinates based on reference sphere is on-the-spot fast repairing method, mainly comprises the following steps:
(1) scene installs and measures equipment: install through calibrated structured light vision sensor, at robot base side reference for installation ball sizing target in the robot flange extremity;
(2) do 4 translations, 6 displacement appearance motions by the teach programming control, utilize structured light vision sensor to measure the sphere centre coordinate of these 10 position reference spheres;
(3) find the solution tool coordinates system with respect to position and the attitude of robot end's coordinate system by the pose data of 10 motions of the sphere centre coordinate that records and robot;
(4) based on the tool coordinates of trying to achieve system position and the attitude with respect to robot end's coordinate system, the tool coordinates system in the definition robot program, and the teaching robot measures track under this tool coordinates system;
(5) after the relative position between structure visual light sensor and robot flange extremity changes, again control the pose that industrial robot is done 4 translations, 6 displacement appearance motions;
(6) again find the solution tool coordinates system with respect to position and the attitude of robot end's coordinate system according to step (2) to the method for step (4), and redefine the tool coordinates system in the robot program;
(7) robot is measured under the tool coordinates of new definition is, not needing again, the teaching robot measures track.
The present invention is based on robot flexibility vision measurement principle, in conjunction with the field calibration technology, provide that in a kind of vision measurement system of robot flexibility fast and accurately, tool coordinates is prosthetic appliance and method, filled up the blank of China in this field, and abroad also temporarily without relevant report, provide technological means for realizing that robot tool coordinate system and TCP repair fast, also satisfy the rear application demand of resuming production fast and measuring that crashes of on-the-spot robot in the robot flexibility vision detection system, have great importance.
Description of drawings
Fig. 1 is the tool coordinates system calibration schematic diagram that the present invention is based on standard ball.
Reference numeral: 1 industrial robot 2 structured light sensor 3 reference spheres
Embodiment
For further understanding summary of the invention of the present invention, Characteristic, hereby exemplify following examples, and coordinate accompanying drawing to be described in detail as follows:
For solving after in present robot flexibility vision detection system, on-the-spot robot crashes, the problem of quick repairing machine device people instrument coordinate system and TCP, the embodiment of the present invention provides that in a kind of vision measurement system of robot flexibility fast and accurately, tool coordinates is prosthetic appliance and method, and its concrete steps are as follows:
(1) utilize free-position plane target drone structured light sensor standardization, the free movement in the sensor measurement space of calibration process midplane target, integrated structure optical sensor mathematical model, the parameter calibration of video camera in the implementation structure optical sensor.Then based on perspective projection cross ratio invariability principle, the light-plane parameters of implementation structure optical sensor is demarcated.According to optical plane structural parameters definition optical plane coordinate system in structured light sensor, and be tool coordinates system in the robot process of measurement with the optical plane Coordinate system definition, with the initial point of optical plane coordinate system as tool center point (TCP);
(2) the manipulator Workspace layout installs and measures equipment at the scene: will be arranged on the robot flange extremity through calibrated structured light vision sensor by mechanical adaptor, at robot base side fixed reference ball sizing target;
(3) do 4 translations, 6 displacement appearance motions by the teach programming control under basis coordinates system of robot, as shown in Figure 1.It is that attitude is constant that 4 translations keep robot end's flange coordinate system relative robot basis coordinates, and to have along basis coordinates in each translation be 3 axial moving.In the motion of 6 displacement appearances, robot end's flange coordinate system relative robot basis coordinates is that position and attitude all change.Robot often moves to a position, structured light sensor is measured the coordinate of the centre of sphere under sensor coordinate system of this position reference sphere, according to the structured light sensor light-plane parameters, sphere centre coordinate is transformed under tool coordinates system, and reads robot pose in this position by Survey Software from robot controller.According to the systematic survey model, find the solution tool coordinates system with respect to the pose transition matrix of robot end's coordinate system by the pose data of 10 motions of the sphere centre coordinate that records and robot; Method for solving can carry out according to existing method, and the below has enumerated two pieces of papers:
Paper 1: Li Jianfeng, Zhu Jianhua, Tang Qing, etc. robot-3 D scanning system Combisweep and commercial Application [J] thereof. photoelectric project, 2007,02:1521.
Paper 2: Li Jianfeng, Tang Qing, Zhu Jianhua, etc. the new method [J] of robot three-dimensional scanning machining system and raising machining precision. computer-aided design (CAD) and graphics journal, 2007.19 (08): 10691074
(4) the robot brand used according to the scene, be that the pose transition matrix is converted to that in this brand robot controller, tool coordinates is the Parametric Representation mode with the tool coordinates of trying to achieve, and the teaching robot measure track tested feature is measured under this tool coordinates system;
(5) cause mechanical adaptor fracture between structured light sensor and robot end when industry spot generation robot collision accident, reinstall after REPAIR WELDING.This moment, tool coordinates was that position and the attitude of relative robot end's coordinate system changes, if robot still by former measurement trajectory measurement, striation may deflect away from tested feature holes, can't measure according to the structured light sensor measurement model.Robot 4 times translation position in trim step (3), and the pose of 6 the displacement appearances motions of 4,5,6 axles motion fine settings by controlling industrial robot make the sphere centre coordinate that structured light sensor can the measuring basis ball;
(6) again find the solution tool coordinates system with respect to the pose transformational relation of robot end's coordinate system by the pose data of 10 motions of the sphere centre coordinate that newly records and robot; And the tool coordinates that redefines in the robot program based on the pose transformational relation of newly trying to achieve is parameter.Need not again that the teaching robot measures track, robot is measured under the tool coordinates system of new definition.