The joints of industrial robots are independently driven by different motors. A four-axis robot is driven by four motors, while a six-axis robot is driven by six motors... When a job command is issued, each motor starts, and you say go east, and I say go west. In the end, it is the process of the left foot tripping the right foot.
What controls them to cooperate and achieve the same goal? The answer is the control system of the robot.
The robot in the control system is equivalent to the human brain, serving as a strategist for the robot and responsible for commanding it to complete tasks. Next, let's understand the structure of this' brain 'and take a look at its unique features.
1. Basic components of a control system
The robot control system mainly consists of the robot system host, teaching pendant, operation panel, signal interface (IO module), analog output interface, servo module (servo driver), network interface (CAN port and Ethernet interface), and communication interface (such as serial port).
The robot system host serves as the core processing unit, responsible for overall scheduling and instruction execution; The teaching pendant is used for manual teaching trajectory and parameter setting, and has independent storage capability; The operation panel provides basic start stop and functional control; The signal interface and analog output interface are responsible for interacting with external devices; Servo module drives the motor and receives position feedback; The network interface supports multi machine online or PC communication, while the communication interface is used for data exchange between robots and other devices.
2. Functions implemented by the control system
The main functions of the control system include memory function (storing operating parameters, motion trajectories, etc.), teaching function (supporting online and offline programming), online function (realizing device interconnection through interfaces such as IO and network), multi axis servo control (supporting multi axis linkage and dynamic compensation), safety protection function (such as electronic fence and collision detection), coordinate system function (supporting multiple coordinate systems such as joints, worlds, tools, etc.), and fault diagnosis function (real-time monitoring of system status and alarm).
These functions collectively ensure that robots can efficiently and stably perform complex tasks while also possessing flexibility and safety.
3. The core process of the control system commanding the robot
▶ Instruction reception and processing
The control system first receives job instructions from the upper computer (such as human-computer interaction interface) or external devices (such as PLC, vision system), clarifying the task objectives (such as movement path, operation actions). For example, by inputting instructions through a teaching pendant or programming software, the system parses the instructions into mathematical models (such as kinematic equations) and converts them into control signals.
▶ Sports Planning and Control
The controller performs motion planning based on target instructions and real-time sensor data (such as position, velocity, and attitude) to generate accurate motion trajectories. For example, by using a servo drive system to convert control signals into motor drive signals, the joints are driven to move along a set path.
▶ Closed loop feedback and adjustment
Sensors collect real-time data on the position, posture, and environmental status of the robot's end effector (such as collision detection), and provide feedback to the control system. The system compares the actual state with the target state, dynamically adjusts control instructions, and ensures action accuracy. For example, if a deviation from the trajectory is detected, the controller will adjust the speed or direction.
▶ Multi-robot collaboration and safety mechanism
In multi-robot systems, the control system plans the paths of each robot through global coordination algorithms (such as virtual velocity field collision avoidance) to avoid collisions. For example, the station controller assigns unique permissions to robots to enter specific areas to ensure job safety.
▶ Execution and external interaction
The control system transmits instructions to the executing mechanism (such as a motor, hydraulic cylinder) through drivers (such as servo drivers, PLCs) to drive the robot to complete the task. At the same time, communicate with external devices such as conveyors and sensors to achieve closed-loop control. For example, PLC adjusts the loop progress of the line based on robot feedback.
▶ Fault handling and logic control
The controller is equipped with built-in logic processing modules (such as PID regulation and fuzzy control) to respond to unexpected situations (such as sensor failures and mechanical jamming) and activate safety mechanisms (such as emergency stop). For example, by interacting with external devices through I/O interface modules, status monitoring and fault alarms can be achieved.
The control system is the "intellectual responsibility" of industrial robots, which helps robots achieve coordinated control of multiple independent servo systems and enables industrial robots to act according to human will.