In the application of industrial robots, the robot body is usually selected to meet the conditions of use, and the end-effectors are customized for different use industries and environments.
For the selection of robot body, the main selection principles are: payload, application industry, maximum action range, operation speed, brake and rotation inertia, protection level, degree of freedom, body weight, repeat positioning accuracy and other nine aspects.
1、Payload
Payload is the maximum load that a robot can carry in its working space. It ranges from, for example, 3Kg to 1300Kg.
If you want the robot to carry the target workpiece from one station to another, you need to pay attention to the weight of the workpiece and the weight of the robot's hand claws to add up to its workload.
Another thing that needs special attention is the load curve of the robot. The actual load capacity will vary at different distance positions in the space range.
2、Industrial robot application industry
Where your robot is going to be used is paramount when choosing the type of robot you need to buy. If you just want a compact pick-and-place robot, a scara robot is a good choice. If you want to place small items quickly, a delta robot is the best choice. If you want robots to work together next to workers, you should choose collaborative robots.
3. Maximum operating range
When evaluating the target application, you should know the maximum distance the robot needs to reach. Choosing a robot is not just about its payload-it's also about the exact distance it will reach. Each company will provide a chart of the range of motion of the robot to determine if it is suitable for a particular application. The robot's horizontal range of motion, noting a non-working area in the immediate vicinity and behind the robot.
The maximum vertical height of the robot is measured from the lowest point the robot can reach (often below the base of the robot) to the maximum height the wrist can reach (Y). The maximum horizontal distance is measured from the center of the robot base to the center of the farthest point that the wrist can reach horizontally (X).
4、Running speed
This parameter is relevant to every user. In fact, it depends on the Cycle Time that needs to be completed in the operation. the specification sheet lists the maximum speed of the robot, but we should know that the actual speed of operation will be between 0 and the maximum speed, taking into account the acceleration and deceleration from one point to another. This parameter is usually measured in degrees per second. Some robot manufacturers will also indicate the maximum acceleration of the robot.
5. Brakes and rotational inertia
Basically every robot manufacturer provides information about their robot's braking system. Some robots are equipped with brakes for all axes, other robot models are not equipped with brakes for all axes. A sufficient number of brakes are required to ensure precise and repeatable positions in the work area. In another special case, when an unexpected power failure occurs, the axes of a weighted robot without brakes will not lock up, risking an accident.
Also, some robot manufacturers provide the robot's rotational inertia. In fact, this would be an additional safeguard for the safety of the design. You may also notice the applicable torque on different axes. For example, if you have an action that requires a certain amount of torque to do the job correctly, you need to check that the maximum torque applicable on that axis is the correct one. If the selection is not correct, the robot may go down due to overload.
6. Protection level
This also depends on the level of protection required for the robot's application. Robots working with food-related products, laboratory instruments, medical instruments, or in flammable environments will require different levels of protection. This is an international standard and needs to be distinguished from the level of protection required for the actual application, or selected according to local codes. Some manufacturers offer different levels of protection for the same robot model depending on the environment in which the robot is working.
7. Degrees of freedom (number of axes)
The number of axes of a robot determines its degrees of freedom. If the robot is to perform simple applications, such as picking and placing parts between conveyor belts, then a 4-axis robot is sufficient. If the robot needs to work in a tight space and the robot arm needs to twist and reverse, a 6-axis or 7-axis robot is the best choice. The choice of the number of axes usually depends on the specific application. It is important to note that a higher number of axes is not just for flexibility. In fact, if you want to use the robot for other applications as well, you may need more axes, and "axes" are only as good as the number of axes you have. But there is a downside to having more axes. If you only need 4 axes for a 6-axis robot, you still have to program the remaining 2 axes.
8. Robot Body Weight
Robot weight is also an important parameter for designing robot cells. If the industrial robot needs to be mounted on a custom table or even a track, you need to know its weight and design the support accordingly.
9. Repeat positioning accuracy
The choice of this parameter also depends on the application. Repeat accuracy is the degree of accuracy/difference of the robot to reach the same position after completing each cycle. Typically, robots can achieve accuracies of 0.5mm or less, or even higher. For example, if the robot is used to manufacture circuit boards, you will need a robot with ultra-high repetition accuracy. If the application being worked on does not require high accuracy, then the robot's repeatability may not have to be as high. Accuracy is usually expressed as "±" in the 2D view. In fact, since the robot is not linear, it can be anywhere within the tolerance radius.
