Reasons and prevention of robot spraying collision-Songle Intelligent Equipment

耀彩网Robot collision events are mainly divided into the following types: collisions between robot bodies; collisions between robots and spray booths; collisions between robots and objects to be painted. Let's share the reasons and prevention of robot spraying collision with Songle Robot.

耀彩网Such collisions are generally rare. This will happen when the spraying robot introduces a new model. The cause of the collision is also relatively simple. That is to say, the unreasonable setting of the spraying action path when performing the teaching of the new model model.

耀彩网This kind of collision is similar to the previous one, and the cause is basically the same.

耀彩网When the robot is imported into a new model, it is generally based on the modeling teaching software according to the actual position of the robot on the scene to model and import the digital model of the new model into the project file for offline simulation. After that, import the profiling teaching program into each robot control cabinet on site. Manual operation, fine-tuning according to the actual position of the car body. If the amount of fine-tuning is large and effective verification cannot be performed. Then there will be collisions when the robot moves automatically.

耀彩网In the process of automatic spraying on site, the robot automatically executes according to the motion path of the profiling teaching. When the object to be sprayed undergoes severe deformation, the robot cannot automatically recognize the actual state of the object to be sprayed, and still runs according to the original motion path. As a result, the collision occurred.

The spraying robot system has its own specific position tracking system. When there is a deviation between the actual position of the object to be sprayed and the feedback position of the robot, the robot will still run according to the set position. This will cause the robot to interfere with the object to be sprayed. Based on the analysis of the actual situation of the paint shop of Haima Car Co., Ltd. (the skid carrying the car body relies on friction on the double chain to ensure the synchronous operation of the skid and the double chain), the main reasons for the position deviation of the sprayed object are as follows :

1) There is serious friction between the skid and the guard plate of the double chain, which leads to relative movement between the skid and the double chain, resulting in deviation. On the one hand, this kind of problem is caused by the deformation and sagging of the double-chain guard plate; on the other hand, the sliding skid is deformed and interfered with the cover plate. The double-chain guard plate blocks the forward movement of the skid.

耀彩网2) The double chain itself is not running smoothly, and there is a situation of crawling. This will also cause relative movement between the skid and the double chain.

耀彩网3) There is a deviation in the position tracking system. There is an error in the position signal received by the robot body. The robot receives the workpiece position information by relying on the double-chain drive wheel to drive the encoder gear, so that the encoder sends out pulse signals to the robot to count the position data. When the encoder has a count deviation, it will inevitably lead to a deviation of the position data received by the robot.

耀彩网This type of collision is the most common type of robot electrostatic spraying system. The main reasons for this type of collision are as follows:

For different collision situations, there will be big differences when taking preventive measures. Below we will analyze the different collision situations one by one.

耀彩网First of all, for the collision between the robot bodies and the collision between the robot and the spray booth, the following two methods are mainly used to avoid. First, set up anti-collision detection. When the machine is performing profiling teaching, a collision avoidance zone is set up with each robot as the center. As shown below:

When the robots are performing normal operations, the A zone centered on the No. 1 robot does not allow the No. 2 robot to move, so as to avoid collisions between the robot bodies. Second, the rotation of each axis of the robot is completed by servo motors. When the pulse feedback value of each axis becomes abnormal after the robot collides, the robot immediately generates an interference alarm to prevent more serious collisions.

Secondly, there are many preventive measures for the collision between the robot and the workpiece. First, control the severe deformation of the workpiece. Multi-detection is added, and professional detection is carried out for the positions that are prone to deformation. Once deformation occurs, an alarm will be generated immediately so as to remind on-site personnel to deal with it. The main detection methods we currently use in the paint shop are: rear door anti-collision detection. Door opening detection, etc. Second, start with preventing deviations in the position of the workpiece. Specifically for the painted car production line, the position of the double-chain cover plate is increased to prevent friction. Strengthen the inspection and maintenance of the chain to ensure that the chain is in a relatively stable running state. For the pulse of the encoder, take measures to prevent fluctuation of the encoder. Under the premise that the hardware position cannot be changed, the effect of encoder pulse stabilization is achieved through software control (increased pulse latch), which further ensures that the double chain and the skid are in a synchronous operation state. details as follows:

耀彩网So, if a positional deviation has really occurred, can it be detected before the robot collides with the workpiece? We conducted an in-depth analysis based on the previous body collision events. It is found that the previous collision positions of the robot body are all the points where the robot is performing path and angle conversion. After each movement path is completed, the robot has to wait until the starting point of the next movement. In this way, we can start from this starting point and formulate a collision avoidance plan.