Many people have discussed robots , wondering why they obey commands. Aside from their appearance, we know little else about robots. Many are interested in the possibility that robots could become highly intelligent "humans" on Earth. If you're truly interested in unraveling these questions, please read our topic today: A Detailed Explanation of Robot Control Technology.
Features of robot control systems
The robot employs a spatial open-link structure, where the movements of each joint are independent. To achieve the trajectory of the end effector, multi-joint motion coordination is required. Therefore, its control system is far more complex than ordinary control systems, possessing the following characteristics:
1. Robot control is closely related to structural kinematics and dynamics. The state of a robot's gripper can be described in various coordinate systems, allowing for the selection of different reference coordinate systems and the application of appropriate coordinate transformations as needed.
2. It is often necessary to solve forward and inverse problems of motion. In addition, the effects of inertial force, external force (including gravity), Coriolis force, and centripetal force must also be considered.
3. Even a simple robot has at least 3 to 5 degrees of freedom, while more complex robots have a dozen or even dozens of degrees of freedom. Each degree of freedom generally includes a servo mechanism, and they must be coordinated to form a multivariable control system.
4. The task of organically coordinating multiple independent servo systems to make them act according to human will, and even endowing robots with a certain degree of intelligence, can only be accomplished by computers. Therefore, a robot control system must be a computer system.
5. The mathematical model describing the robot's state and motion is a nonlinear model. Its parameters change with different states and external forces, and there is also coupling between the variables.
6. Robots can move in different ways and along different paths, thus presenting an "optimal" problem. More advanced robots can use artificial intelligence methods to build a vast information database using computers, and then use this database for control, decision-making, management, and operation.
Traditional automated machinery focuses on its own movements, while the control system of an industrial robot emphasizes the interaction between the robot and the object it manipulates. Therefore, a robot control system is a coupled, nonlinear, multivariable control system closely related to kinematics and dynamics principles.
Depending on the specific work situation, there can be various control methods, ranging from simple programming automation and microprocessor control to small computer control, and so on.
Characteristics and basic requirements of robot control systems
To effectively control a robot, it is crucial to understand the characteristics of the robot being controlled. Based on our understanding of robot dynamics, it possesses the following characteristics:
1. A robot is essentially a nonlinear system. Many factors can cause nonlinearity in robots, including structural aspects, transmission components, and drive elements.
2. There is a coupling effect between the joints, which means that the movement of one joint will have a dynamic effect on other joints, so that each joint must withstand the disturbances caused by the movement of other joints.
3. It is a time-varying system, and its dynamic parameters change with the position of the joint movement.
From a usage perspective, a robot is a special type of automated equipment, and its control has the following characteristics and requirements:
1. Multi-axis motion coordination control to generate the required working trajectory. Because the robot's hand movement is a composite motion of all joint movements, in order for the hand to move according to the set rules, it is necessary to control the coordinated movements of each joint well, including the coordination of movement trajectory, movement timing, and other aspects.
2. High positioning accuracy and a wide speed range
3. The system's static error rate should be small.
4. The speed error coefficients of each joint should be as consistent as possible.
5. No position overshoot, and the dynamic response should be as fast as possible.
6. Acceleration (deceleration) control is required.
7. From an operational perspective, the control system should have a user-friendly interface to minimize the demands on the operator.
8. From a system cost perspective, it is required to minimize the hardware cost of the system and make greater use of software servo methods to improve the performance of the control system.
Robot control methods
There is no unified standard for classifying industrial robot control methods:
A. Robot motion control methods
a. Robot motion control methods
(1. Robot position control methods: positioning control methods—fixed position method, multi-point position method, servo control method; path control methods: continuous trajectory control, point-to-point control)
(2. Robot speed control methods: speed control methods—fixed speed control, variable speed control; acceleration control methods—fixed acceleration control, variable acceleration control)
(3. Robot force control methods)
b. Robot action sequence control method
B. Robot teaching and control methods
(1. Teaching with actual robots: direct teaching method - power stage disconnected from teaching, servo stage connected for teaching; remote teaching method - teach pendant teaching method, joystick teaching method, master-slave teaching method)
(2. Teaching without robots: Indirect teaching method - displaying values using model robots and special tools; Offline teaching method - displaying values using numerical input, graphical display, and software language teaching)
Robot control system structure and working principle
An industrial robot system typically consists of two main parts: the robot body and the control system. The main components of a robot control system include computer hardware and operating control software, input/output devices and apparatus, driver system, and sensor system.
The control system of an industrial robot is an important component of the robot, enabling it to complete predetermined work tasks. Its basic functions include:
1. Memory function
2. Teaching function
3. Communication function with peripheral devices
4. Coordinate setting function
5. Human-machine interface
6. Sensor Interface
7. Position Servo Function
8. Fault diagnosis and safety protection functions
Of course, there is much more to learn about robot control, such as: single-joint position servo control, robot force control, and intelligent robot control, etc.
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