Basic components of traditional articulated robots
Traditional articulated robots mainly consist of body structural components, reducers, servo motors, controllers, etc.
Body structural components
The industrial robot body consists of a rotating base, upper arm, and lower arm, and is the most direct external mechanical structure of the robot. The robot body structural components are made of various materials, including cast iron, cast steel, cast aluminum, and structural steel.
reducer
Reducers are used to bear the loads of various joints in a robot. The high-speed, low-torque output from the motor is transformed into low-speed, high-torque output through the reducer, thereby increasing the output torque of each axis of the robot and enabling the robot to withstand larger loads. Robots place high demands on reducers, requiring them to be small in size and weight, have a large reduction ratio, high precision, and be shock-resistant.
Currently, there are two main types of reducers widely used in multi-joint robots: RV reducers and harmonic reducers. RV reducers, due to their higher rigidity and rotational accuracy, are generally placed in heavy-load positions such as the upper arm and shoulder; harmonic reducers are placed in the forearm and wrist.
Drive control system
The drive control system is mainly used to control the robot to move according to the set motion parameters. It mainly includes servo drivers, servo motors, and controllers.
(1) Servo motors are mainly used to drive the joints of robots, and are required to have the highest power-to-weight ratio and torque-to-inertia ratio, high starting torque, low inertia and a wide and smooth speed range;
(2) The servo driver is a device that drives the servo motor to move. According to the instructions of the controller, the servo driver provides the servo motor with the corresponding current, thereby ensuring that the servo motor moves according to the required speed, acceleration, and position, so as to ensure that the movement of the robotic arm meets the set requirements.
(2) The controller can manually set its internal parameters to achieve multiple functions such as position control, speed control and torque control of the robot.
The role of the "axis" in a six-axis serial robot
Traditional six-axis industrial robots typically have six degrees of freedom, commonly including rotation (S-axis), lower arm (L-axis), upper arm (U-axis), wrist rotation (R-axis), wrist swing (B-axis), and wrist oscillation (T-axis). The six joints work together to achieve the six degrees of freedom motion at the end effector.
One axis: The first axis is the part that connects to the base, bearing the weight of the entire robot and the left and right rotation of the base;
Two axes: control the forward and backward swinging of the robot's main arm;
Three axes: control the forward and backward swinging of the robot's forearm;
Four-axis: Controls the rotation of the robot's forearm;
Five-axis: controls and finely adjusts the rotation of the robotic wrist, typically enabling product flipping after gripping.
Six-axis: Used for rotation of the end-effector, allowing for more precise positioning of the product.
TIps
Depending on the application scenario, the wrist section also has different structural designs. B (bend) indicates a bending structure, and R (revolve) indicates a rotating structure.
Advantages and disadvantages of six-axis serial robots
Advantages
Compact structure, small installation footprint;
It exhibits good flexibility, a wide range of hand reach, and excellent obstacle avoidance performance;
It has no moving joints, good joint sealing performance, low friction, and low inertia;
The joints have low driving force and low energy consumption.
Disadvantages
There are balance issues during the movement, and the control is coupled.
When the upper and lower arms are fully extended, the robot's structural rigidity is poor.
Singularities exist during motion control, and the algorithms used for control must avoid them.
