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Industrial robot selection is to determine the specific model of the robot according to the requirements of use.

Industrial robot selection steps:

First: choose the corresponding robot according to the application industry, such as spraying, palletizing, welding, etc. There are special robots.

Second: Calculate the center of gravity and moment of inertia of the load to determine the specific model of the robot.

First, according to the shape and weight of the workpiece, design the robot's claw, and then calculate the total weight of the claw + workpiece, the position of the center of gravity, the moment of inertia relative to the TCP point of the robot flange and align with the TCP coordinate system, and the above parameter values can be automatically calculated by three-dimensional software (SolidWorks).

Figure 1 Robot load center of gravity and moment of inertia

SolidWorks methods and procedures for viewing the center of gravity and moment of inertia of the end tool:

Step 1: First create a new coordinate system on the claw, the Z axis of this coordinate system is aligned with the robot TCP Z axis, the direction of the X and Y axes is not required, this example is the coordinate system 1, as shown in the figure below:

Step 2: Open the Quality Properties dialog box and report the coordinate values relative to Select the coordinate system in Step 1, in this case coordinate system 1, SolidWorks will automatically calculate the position of the center of gravity and the moment of inertia.

Note: Do not choose the wrong coordinate system, otherwise the calculated result is not the value that the robot wants, then it is a big mistake.

Step 3: Moment of inertia selection is determined by the center of gravity, and the coordinate system of the output is aligned, that is, the moment of inertia Lxx, Lyy, and Lzz in the red box above.

Then, according to the total weight of the claw + workpiece, preliminarily select a robot, find the allowable load curve diagram of the robot wrist (this figure can only judge the torque, can not judge whether the moment of inertia exceeds the standard), according to the distance between the center of gravity position of the claw + workpiece (XYZ three directions) relative to the robot flange TCP, judge whether the weight of the claw + workpiece is within the allowable load range of the robot.

Figure 2 Load curve of 16 robot wrist

In addition to the allowable load curve of the robot wrist, robot manufacturers usually provide a robot load verification tool, which will automatically calculate the 4, 5, and 6 three-axis torque and moment of inertia after entering the weight of the claw + workpiece, center of gravity, and moment of inertia, and give the judgment result.

Table 1 FANUC robot checklist

Finally, according to the requirements of robot use, select the protection level of the robot, when used in casting, forging, grinding and other harsh environments, you need to choose IP67 robots, and choose the standard version in the conventional machining environment.