What are the core technologies of (collaborative) robots?
Collaborative robots have only begun to gain widespread attention in recent years, but in fact the concept of collaborative robots was first proposed in the 1990s.
These two problems generally exist in the method of human-machine cooperation safety setting in the market: one is to set up safety gratings to protect personal safety, which increases equipment and cost investment; second, the operation is complicated, and unskilled personnel cannot control the robot.
Product definition of collaborative robots:
Flexibility
Compared with industrial robots on traditional large-scale production lines, collaborative robots need to cooperate with humans, and their structure size should be lighter, more flexible, and have more space for manipulation.
Ease of use
Collaborative robots emphasize ease of use. For example, they can be followed by sensory devices through gestures, lowering the barrier to use. Frontline workers may only need a few hours to operate, eliminating the need for complex programming and configuration of traditional industrial robots.
Safety
Collaborative robots are mainly used for human-machine collaboration. They must be safe to work with humans and cannot harm humans due to accidents. This has high requirements for the perception and control of collaborative robots.
Low cost
Collaborative robots are oriented to small and medium-sized enterprises. The lowest possible cost is very important, but often the low cost and performance will also be reduced. It is relatively difficult to improve performance while controlling the cost.
For a collaborative robot to possess the above four characteristics, it must have the ability to sense, control and limit torque. By sensing the small external torque changes and reacting to avoid collisions, the process of human-machine collaboration is easier and safer.
1. Ultra-small, powerful servo driver
The physical size of a driver is small enough to be directly mounted on the robot joint, which ensures that the size of the robot is small and compact. The servo driver is directly installed on the robot joint. Placing the driver close enough to the encoder feedback can save cables, reduce interference effects, obtain relatively low EMI and RFI indicators, and greatly improve system stability. Another feature that makes the drive easier to integrate into the joint is the inherent robustness of the drive, which can withstand the extremely high mechanical acceleration and deceleration in the joint.
2. Double closed loop control algorithm
The double closed-loop control algorithm can improve the performance of the servo motor to the optimal state. Each axis in the system adopts double closed-loop control algorithm to improve the positioning accuracy of the joint end position of the rear end of the reducer. Incremental encoders and Hall components are placed at the front of the gearbox as speed loop feedback, and 19-bit high-resolution absolute encoders are used as load end position feedback.
3. Motion redundancy
Kinematic redundancy is useful for operating several robots in a specific space, because motion interference is easy to handle. Six degrees of freedom is the minimum number of degrees of freedom with the ability to complete spatial positioning. Robots with more than six axes are collectively called redundant degrees of freedom robots. Compared with traditional 6-joint robots, 7-joint robots can extend the arm at multiple angles to approach a specific original. Redundant degrees of freedom robots have more advantages in avoiding obstacles, overcoming singularities, flexibility and fault tolerance. Therefore, industrial robots with redundant degrees of freedom will have more uses in complex working environments.
4. Torque sensor
In a human-machine collaboration environment, these robots are arranged to complete high-speed, high-precision tasks. Using cameras, force sensors and other sensing elements, the robot can sense the presence of people and make corresponding actions to avoid harm to people. In some cases, the torque sensor is placed behind the motor gearbox to directly detect any rapid increase in external torque; in other cases, the robot needs to output a certain torque to lift the load and move the load from one position to another. . When the robot recognizes an abnormal torque increase during movement, such as a collision, it will automatically stop.
5. Safety sensor
If you want industrial robots to cooperate with humans, you must first find a way to ensure the safety of workers. These sensors come in various forms, from cameras to lasers, etc., with only one purpose, which is to tell the situation around the robot. The simplest example is the laser safety sensor on the elevator door. When the laser detects an obstacle, the door will immediately stop closing and retract to avoid collision. The same goes for most safety sensors in the robotics industry.
6. Parts detection sensor
In part picking applications, (assuming there is no vision system), you cannot know whether the robot gripper has picked up the part correctly. The part inspection application can provide you with feedback on the position of the gripper. For example, if the gripper misses a part, the system will detect the error and repeat the operation to ensure that the part is picked correctly.