Principles of industrial robot selection

In the process of using industrial robots, the robot body is usually selected to meet the use conditions, and the end actuator is customized for different occupations and environments.

Regarding the selection of the robot body, the primary selection principle is: useful load, use occupation, maximum action scale, operation speed, braking and moment of inertia, protection level, degree of freedom, body component, repeated positioning accuracy and other nine aspects.

Principles of industrial robot selection

Principles of industrial robot selection

1 Useful load

The useful load is the maximum load that the robot can carry in its working space, ranging from, for example, 3 kg to 1300 kg.

If you want the robot to finish moving the workpiece from one station to another, you need to pay attention to adding the weight of the workpiece and the weight of the robot's gripper to its working load.

Other special needs to be paid attention to are the load curve of the robot, and the actual load capacity will be different at different intervals of space scale.

2 Occupations in the use of industrial robots

Where your robot will be used is the first condition when you choose the type of robot you want to buy.

If you just want a compact pick-and-place robot, the SCARA robot is a good choice. If you want to quickly place small items, the Delta robot is the best choice. If you want a robot to work next to a worker, you should choose a cobot.

3 Maximum action size

When evaluating where the policy is to be used, it is important to know the maximum interval between the arrival of the robot's needs. Picking a robot isn't just about its useful payload – it's about how often it arrives.

Each company gives a graph of the size of the robot's movements, so that it can be judged whether the robot is suitable for a particular use. The scale of the robot's horizontal movement, pay attention to the robot's close and rear non-working areas.

The maximum straight height of the robot is measured from the lowest point that the robot can reach (usually below the base of the robot) to the maximum height that the wrist can reach (Y). The maximum horizontal actuation interval is the interval (X) from the center of the robot's base to the center of the farthest point that the wrist can reach horizontally.

4 Speed of operation

This parameter is relevant to every user. In fact, it depends on the Cycle Time at which the job is requirement. The standard table clarifies the maximum speed of this type of robot, but we should know that considering the acceleration and deceleration from one point to another, the speed of the actual operation will be between 0 and the maximum speed.

This parameter is usually measured in degrees per second. Some robot manufacturers will also indicate the maximum acceleration of the robot.

5 Braking and moment of inertia

Basically every robot manufacturer supplies information about their robot's braking system. Some robots have brakes on all axes, while others do not have brakes on all axes. To ensure a precise and repeatable orientation in the work area, a sufficient number of brakes are required.

In other special cases, when an unexpected power failure occurs, the load-bearing robot shaft without brakes will not lock, and there is a risk of accidents.

At the same time, some robot manufacturers also supply the moment of inertia of the robot. In fact, this will be an additional guarantee in terms of the safety of the plan.

You may also notice the applicable torque on the different axles. For example, if your action requires a certain amount of torque to finish the job correctly, you need to see if the maximum torque applied on that axis is correct. If the selection is incorrect, the robot may be overloaded and go down.

6 Infrared-protection level

This also depends on the level of protection required for the use of the robot. Robots may work with food-related products, laboratory instruments, and medical devices in flammable environments with different levels of protection.

This is an international standard that requires the level of protection required for practical use, perhaps selected according to local norms. Some manufacturers will provide different levels of protection for the same type of robot according to the different environments in which the robot operates.

7 degrees of freedom (axes)

The number of robot axes determines its degrees of freedom. For simple uses, such as picking and placing parts between conveyor belts, a 4-axis robot is sufficient. If the robot needs to work in a small space, and the robotic arm needs to rotate crookedly, a 6-axis or perhaps 7-axis robot is the best choice.

The selection of the number of shafts usually depends on the detailed use. It is important to note that a little more axes is not just for flexibility.

In fact, if you're thinking about using the robot for other purposes, you may need more axes, and you don't want to use the "axes" until you use them. However, if you only need 4 axes for a 6-axis robot, you still have to program the remaining 2 axes.

8 Robot body components

Robot components are also an important parameter for planning robot cells. If an industrial robot needs to be installed on a custom-built workstation or even a rail, you need to know its weight and plan for the corresponding support.

9 Repeatability

The choice of this parameter also depends on the use. Repeatability is the accuracy/difference of the robot in the same direction after each cycle. Generally speaking, robots can achieve an accuracy of less than 0.5mm, or even higher.

For example, if a robot is used to make circuit boards, you need a robot with ultra-high repeatability. If the precision of the application is not high, then the repetition accuracy of the robot can not be so high. Accuracy is often expressed as "±" in 2D views. In practice, because robots are not linear, they can be anywhere within the official service radius.

Principles of industrial robot selection

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