Specifications of Industrial Robot
The specification parameters of industrial robots include the number of control axes, radius of motion, installation mode, range of action, speed of movement, weight that can be carried by the wrist, allowable load torque of the wrist, allowable moment of inertia of the wrist, repeated positioning accuracy, robot quality, installation conditions, etc.
Below is the robot parameter table of the FANUC M-710iC series:
Table 1 Robot specification table
Torque is a symbol of strength. The wrist load torque cannot exceed the standard, otherwise the servo motor will brake and hold tightly, and the robot will immediately stop moving, which will cause the robot's big arm to break in extreme cases.
Moment of inertia is an inherent property of an object, which is used to measure the difficulty of external forces to change the original motion state of an object. The moment of inertia of the wrist load can not exceed the standard, and the servo motor inertia ratio (load inertia divided by the motor rotor inertia) is usually required to be less than 10 times, otherwise, it will affect the angular acceleration of the robot during operation, and in severe cases, it will cause motor damage.
In addition, servo motor power = torque × angular velocity, so the power of each axis motor can be roughly known through the torque and angular velocity in the robot specification table. For example, FANUC M-710iC/50 robot, J6 axis allowable torque 147Nm, angular velocity 6.2 rad/s, then J6 axis servo motor power P=147×6.2=911.4W, if nothing else, the power of J6 axis servo motor should be 1kW.
For 6-axis robots, the radius of motion refers to the J5 axis rotation center range, in addition to the need to pay attention to the J1 axis range of motion, some robots J1 axis can rotate ± 185 °, so that 360 ° full coverage can be achieved, but some robots J1 axis can only rotate ± 175 °, the robot is directly behind the robot within 10 ° range of the robot can not be covered, in the robot cell layout need to pay attention to the J1 axis range of motion, try not to arrange the equipment directly behind the robot.
Although the installation method allows inclined angle installation, it has an impact on the range of motion of the robot after tilt installation.
For example, FANUC M-710iC/50 robot, robot installation angle 0 ~ 180 °, but in different angle ranges, the robot range of motion is also different, for example, in the setting angle range (3), the robot J1 axis is in the range of 44 ~ 136 ° or -136 ~ -44 °, the robot J5 axis rotation center range is limited, because the weight of the robot body has begun to generate additional torque on the J1 axis, especially the J1 axis at ± 90 °The force arm generated is the longest and the more restricted the range.
Figure1 The robot sets the angle range
Figure 2 The robot sets the range of action of the angle range (2).
The wrist load weight is a maximum value, which can only be achieved within a certain distance from the center of the robot end flange, and the weight of the load is allowed to gradually decrease as the direction of the workpiece center from the robot end flange increases.
The wrist allows the load torque, and only needs to check whether the 4, 5, and 6 three-axis load exceeds the standard.
The repeatability and repeatability path accuracy are determined according to the ISO9283 "Industrial Robot Performance Specifications and Test Methods".
Definition of robot repeatability (RP): the degree of consistency of the same pose after repeating the response from the same direction n times.
In addition to repeating positioning, there is also a repeatable path accuracy.
Definition of robot repeat path accuracy (RT): the degree of consistency of the real trajectory when the same command trajectory is repeated n times.
Some robot manufacturers do not mark this repeat path accuracy, repeat path accuracy is much worse than repeat positioning accuracy, deviation in ± 0.2 ~ 0.5mm, so the articulated robot walking straight line is inaccurate, for example, it is difficult to use the articulated robot to directly insert the cylindrical pin into the hole (pin hole with H7/h6) (Note: the robot can achieve pin hole assembly by soft floating).
The installation conditions of the robot mainly refer to the temperature and humidity and vibration acceleration, and some robots will also have altitude requirements, for example, some robots require use below 1000 meters above sea level.
Figure 3 Robot range of motion
— Leave a Comment