The robot origin, also known as the “mechanical origin” or “mechanical zero point”, is an inherent and physically unchangeable reference position of the robot’s mechanical structure. It is a fixed point determined by the mechanical machining accuracy during the production and assembly of robot manufacturers, usually marked by the mechanical limit of each joint of the robot and the triggering position of sensors, and is the “coordinate origin” of the robot kinematic model.
From a physical perspective, the origin is the starting boundary of the motion range of each joint of a robot, and is a “natural reference” that is fixed during the design of mechanical structures. For example, each rotating joint of an industrial robotic arm is equipped with a mechanical stopper. When the joint moves to the position of the stopper, the origin sensor is triggered, and the position of the joint at this time is the origin of the axis; The origin of multi joint collaboration is the combined state where all joints simultaneously reach their respective mechanical reference positions.
Home point, also known as “regression point” or “starting point” (Home Position), is the “functional reference position” set by the user or system in the robot control system. It is not an inherent physical point of the mechanical structure, but a “safe, convenient, and universal” reference position selected from the robot workspace based on practical application needs. Essentially, it is a manually defined “logical benchmark”.
The setting of the home point is flexible and can be adjusted according to the homework scenario. For example, in the workstation of a welding robot, the home point may be set in a safe area away from the workpiece and fixture; In the sorting robot system, the home point may be set in the middle position between the picking and discharging positions to quickly switch the operation process. Some robot systems will preset a default home point, but users can redefine it according to their actual needs.
Core characteristics of robot origin
Fixed and immutable: The origin is determined by the mechanical structure, and once the robot is assembled, the origin position is permanently fixed and cannot be changed through software programming or operation. If the origin needs to be adjusted, the mechanical structure must be dismantled and the sensor must be recalibrated, which is a hardware level adjustment.
Uniqueness: The origin of each robot has a unique determinacy and serves as an absolute reference for the robot coordinate system (such as joint coordinate system, world coordinate system). No matter what state the robot is in, the physical position of the origin remains unchanged.
Mandatory: The origin is the “necessary reference” for robot system initialization and coordinate system calibration. After the robot is powered on, if the “return to origin” operation is not performed, the system cannot determine the absolute position of each joint, usually limiting the robot’s range of motion and even unable to start the job program – this is because the robot’s motion control relies on coordinate calculation based on the origin.
The core characteristics of the Home point
Flexible and variable: The home point is a software level setting, and users can modify its position at any time through programming or teaching aids based on factors such as job requirements, safety regulations, and process optimization. A robot can set multiple home points for switching the starting position of different work processes.
Non uniqueness: There is no fixed limit on the number and location of Home points, which depends entirely on the actual application scenario. For example, a handling robot can set three different reference positions: “standby home point”, “home point before material retrieval”, and “home point after material discharge” to improve operational efficiency.
Practicality: The core values of the Home point are “convenience” and “security”. It does not need to be the extreme position of the mechanical structure, but rather a position that is interference free, easily accessible, and can be quickly switched to the work position in the robot workspace, as the recovery position after program startup, reset, and emergency stop.
The core function of robot origin
The basis for establishing a coordinate system: All coordinate calculations of the robot, such as joint angles and spatial positions of end effectors, are based on the origin. Without an origin, the system cannot determine the absolute position of each joint, and motion control will lose its basis, leading to the robot getting lost.
The benchmark for precision calibration: After long-term operation, the robot may experience position deviation due to mechanical wear, load changes, and other factors. At this point, it is necessary to perform the “return to origin” operation to allow each joint to return to the mechanical reference and recalibrate the coordinate system to ensure motion accuracy.
The necessary steps for system initialization: After the robot is powered on, the system will automatically execute the “find origin” process (or prompt the user to manually return to the origin). Only after confirming the absolute position of each joint can the robot enter the ready state and allow the execution of the job program.
The core functions of the Home point
The starting position of the homework program: Most robot programs are written from the Home point – the robot starts from the Home point, performs tasks such as material picking, processing, and assembly, and returns to the Home point after completion, forming a standardized workflow.
Safety reset and emergency recovery: In the event of an abnormality (such as collision, signal interruption) or emergency stop during the operation process, the robot can automatically return to the home point through the program, avoiding staying in dangerous areas or interfering positions, facilitating fault diagnosis and recovery of operations.
Transition position for multitasking switching: In complex job scenarios, when the robot needs to switch between different job tasks, it can first return to the Home point and then switch from the Home point to the job position of the new task, avoiding motion interference between different tasks and improving process coherence.
Understanding the difference between the two is the foundation of robot operation and programming: mistakenly using the Home point as the origin may lead to coordinate system calibration errors; Neglecting the importance of the origin and relying solely on the Home point may lead to abnormal motion accuracy of the robot; Reasonably utilizing the flexibility of the Home point can greatly optimize the workflow and enhance the application value of robots.
