Seemingly simple, the difference between industrial robot systems and humanoid robot systems is not significant. This article introduces the five major systems of industrial robots. They are divided into five modules: control, drive, perception, ontology, and execution.
Ⅰ. control system
We all know that each joint of a robot is equipped with a separate motor for execution. A six-axis robot is a type of robot with six servo motors. Each axis has its ideas on how much to rotate and whether to go east or west. At this point, a central control platform is needed to coordinate them, and the robot's control system emerges.
The control system, equivalent to the "brain" of the robot, is mainly responsible for issuing human work instructions to the robot and converting human language instructions into robot language instructions. Simply put, the function of a robot control system is to control the robot's actuators to complete specified movements and functions based on the robot's job instruction program and the feedback signals from sensors.
The main components of this system include 8 parts:
1. Robot system host: the central processing unit of the control system and the dispatch and command organization. Responsible for calculating and issuing all action commands, such as deciding whether the arm should turn left 30 degrees or right 50 degrees.
2. Teaching pendant: The teaching robot's work trajectory and parameter settings, as well as all interactive operations, have independent storage units. Like the "remote control+notepad" of a robot, you can teach it to walk the action step by step (such as welding path), and it will remember each step and repeat it.
3. Operation panel: generally composed of basic components such as buttons or buttons, indicator lights, etc., to complete basic functional operations or start stop. For example, pressing "start" will make the robot move, and pressing "emergency stop" will immediately brake.
4. Signal interface (IO module): IO interface that interacts with external devices or workstations. The "ears and mouth" of the robot are used to receive external signals (such as sensor triggers) or send signals (such as notifying the conveyor belt to start).
5. Analog output interface: input and output ports for various states and control commands. An interface that can transmit "degree signals", such as controlling the amount of paint to be "more" or "less".
6. Servo module (servo driver): provides driving power for servo motors and controls them to send and receive position commands. The 'muscle controller' of the robot precisely controls how much force and how many times the motor rotates.
7. Network interface: ① CAN port: Multiple machines are connected through CAN communication, allowing multiple robots to "chat in groups" and work together (such as one moving goods and the other receiving goods). ② Ethernet interface: Multiple or single robots can directly communicate with a PC through Ethernet, supporting TCP/IP communication protocol. Similar to connecting a computer via an Ethernet cable for remote debugging or uploading programs.
8. Communication interface: Implement information exchange between robots and other devices, usually with serial interfaces. It can be understood as a USB file transfer.
Ⅱ. driving system
The driving system is the power source of the robot, equivalent to the "cardiovascular system". The driving system generally consists of two parts, the first of which is the "heart blood supply", which is the driving device; The second one is "vascular transmission", which refers to the transmission mechanism.
There are generally three driving methods for robots: hydraulic drive, pneumatic drive, and electric drive. As the name suggests, they use liquid or air energy as the power source, or directly use electric energy to drive. Each of these methods has its own advantages and disadvantages, and they are good power sources suitable for robot operation. Our Braun robots are generally driven by electricity because it is more environmentally friendly and convenient.
The transmission mechanism of robots is generally composed of servo motors and reducers, using gears or belts for transmission. Among them, the servo motor and reducer constitute the driving structure of the robot.
Taking the drive structure of the Braun robot as an example, it consists of a motor and a reducer. The motor uses an absolute servo motor, and the reducer has two types: RV reducer and harmonic reducer. The motor and reducer are generally connected using a reducer shaft or a wave generator.
Ⅲ. Perception system
Simply put, a perception system is a sensor system that undertakes the "perception" part of robots, including force perception, visual perception, temperature perception, etc. It is mainly linked with the control system to provide environmental information.
The perception system includes internal sensors and external sensors.
Internal sensors: detect the robot's own state, such as position, velocity, acceleration, force, and other parameters, to provide feedback for motion control.
Position sensor: measures joint angles or displacements through encoders, photoelectric encoders, etc., to ensure that the robot moves along a predetermined trajectory.
Speed/acceleration sensor: detects joint motion speed and acceleration, assists in dynamic control.
Force/torque sensor: measures the force or torque of grasping an object, adjusts the grasping force to avoid damaging the object.
Attitude sensor: detects the overall posture of the robot through IMU (Inertial Measurement Unit) and other sensors to ensure stable operation
External sensors: Knowing the environment in which the robot is located and its relationship with external objects, assisting in environmental adaptation and task execution.
Visual sensors: Identify the shape, color, and position of objects through cameras or LiDAR to achieve visual guidance (such as welding and sorting).
Tactile sensor: detects surface features or pressure changes of objects in contact, used for grasping control.
Force sensor: measures the interaction force between the robot and the object to prevent overload or slipping.
Proximity sensor: detects object distance through infrared or ultrasonic waves to avoid collisions.
Auditory sensor: receives sound signals for speech recognition or environmental monitoring.
Ⅳ. Ontology system
The robot body is equivalent to the framework of the human body, which is the "flesh and blood skeleton part". Including the hand (end effector), wrist, arm, waist, and base, it generally has 4-6 degrees of freedom, of which 3 are used to determine the position of the end effector, and the other 1 or 3 are used to determine the direction (posture) of the end effector.
Ⅴ. End system
This is a component of the robot that directly executes tasks. As the "last link" between the robot and the external environment, it determines the flexibility and efficiency of the robot's operations. It is also called the "end effector". Mainly responsible for executing ultimate tasks, such as arranging robot spraying, welding, or handling tasks, which are determined by the end fixtures of the robot. This is also why robots have a wide range of practicality. Different execution fixtures are installed at the end of the robot, and the robot has different abilities.
The above are the five basic systems that make up industrial robots, just like "humans", with a brain responsible for command, a source of power, sensory perception, flesh and blood, and fingers that make good use of tools. Of course, it may not seem particularly complicated, but in reality, the content involved is rich and profound. To understand and learn about robots, one must personally get started to have a more thorough understanding.