The control method of industrial robots - KUKA robots

At present, the most widely used robot on the market is industrial robots, which are also the most mature and complete robots. Industrial robots have a variety of control methods, what are the control methods of industrial robots?

The control method of industrial robots - KUKA robots

The control method of industrial robots - KUKA robots

1. Point Control (PTP)

Point azimuth control is widely used in mechatronics and robotics industries. CNC machine tool tracking part contour, industrial robot fingertip track control and walking robot path tracking system are typical applications in machinery manufacturing.

In the process of manipulation, the industrial robot is required to be able to move quickly and accurately between adjacent points, and there is no regulation for the movement track to reach the target point.

Positioning accuracy and time required to move are the two top skill indicators for this form of manipulation. This method of manipulation allows for low positioning accuracy and is typically used for loading, unloading, and handling spot welds, where the insert part on the board should maintain the exact orientation of the end effector at the target point. This method is relatively simple, but it is difficult to achieve the positioning accuracy of 2-3um.

The point control system is actually an azimuth servo system. Its basic structure and composition are basically the same, but the degree of control clutter varies depending on the emphasis; According to the feedback, it can be divided into closed-loop system, semi-closed-loop system and open-loop system.

2. Continuous track control form (CP)

Under the control of the point orientation, the start and end velocities of the PTP are 0, and various speed planning methods can be used during this period.

CP control is to continuously control the position of the end actuator of the industrial robot in the working space. The velocity of the center point is not zero. It's constantly moving. The velocity of each point is obtained by looking forward at the velocity. Generally speaking, the speed foresight method is the first to be used for continuous track control: travel speed limit, corner speed limit, tracking speed limit, maximum speed limit and contour error speed limit.

This control method requires it to move within a certain range of accuracy in strict accordance with the predetermined track and speed, the speed is controllable, the track is smooth, the movement is stable, and the task is completed.

The joints of the industrial robot are continuous and continuous, and after synchronous movement, the end effector can form a continuous track. The primary skill indicator of this form of manipulation is the tracking accuracy and stability of the end effector orientation of the industrial robot, usually arc welding and painting. This control method is used for robotic deburring and inspection.

3. Force (torque) manipulation method

With the continuous expansion of the application boundary of robots, visual empowerment alone can no longer meet the needs of chaotic practical applications. In this case, it is necessary to introduce force/moment to manipulate the output, or it is necessary to introduce force or moment as closed-loop feedback.

When the object is grabbed and placed, the assembly is in progress, and in addition to accurate positioning, the appropriate force or torque needs to be applied, and then it is necessary to apply the (torque) servo. The operating principle is fundamentally the same as that of the azimuth servo, but the input and feedback are not azimuth signals, but force (torque) signals, so it is necessary to use a strong (torque) sensor in the system. Sensing features such as proximity, adaptive control, and swipe are also sometimes used.

Since the contact between the gripper and the work surface is often a cluttered surface that is not known, the perception of force/torque should also be multidimensional.

4. Intelligent control form

Robot intelligent control is a form of control through sensors, such as cameras, intelligent information processing, intelligent information feedback and intelligent control decision plan. Image sensors, ultrasonic emitters, lasers, conductive rubbers, piezoelectric and pneumatic components, travel switches and other electromechanical components) to gain knowledge of the surrounding environment and make decisions based on their own internal knowledge base.

The development of intelligent manipulation skills depends on the rapid development of artificial intelligence expert systems such as artificial neural networks, genetic algorithms, and genetic algorithms. In recent years, intelligent control skills have made significant progress. Fuzzy manipulation theory, artificial neural network theory and their integration have greatly improved the speed and accuracy of robots. It is mainly used for multi-joint robot tracking control, lunar robot control, weeding robot control, cooking robot control, etc.

Robot intelligent control can be divided into: fuzzy control, adaptive control, optimal control, neural network control, fuzzy neural network control and expert control.

What are the control methods of industrial robots? Robots, in most cases, are still in the relatively low-level stage of spatial positioning and control, without much intelligent content, and there is still a long way to go in interval intelligence. Therefore, China's robotic experts divide robots into two categories, namely industrial robots and intelligent robots, starting from the application environment.

The control method of industrial robots - KUKA robots

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