The principle of absolute motion programming involves positioning the robot to the target position through absolute values, including three motion modes: PTP (point to point), LIN (linear) and CIRC (circular path). Each mode has specific programming format and parameter requirements, such as target point type, trajectory approach setting, etc. During the programming process, it is necessary to load the program, check or reinitialize the relevant setting values, create motion instructions, and save them after completion.
Absolute motion programming is crucial in robotics and automation. It defines an object’s movement based on a fixed coordinate system.
In this programming approach, the starting and ending positions are precisely set in absolute terms. This ensures accurate and repeatable movements. For example, in a robotic arm, commands specify exact X, Y, and Z coordinates.
The advantage is high precision and predictability. It enables complex tasks with consistent results, making it popular in industries like manufacturing and assembly.
1 Absolute motion programming principle
The absolute motion of the robot is to move to the target position with the help of absolute values.
(1) Motion mode PTP
The editing form for the motion mode PTP is: PTP target point .
Among them, the target point types are POS, E6POS, AXIS, E6AXIS, and FRAME. They can be given by Cartesian based on the BASE coordinate system or axis coordinates. If all components of the target point are not given, the controller will apply the value of the previous position to the missing components. C_PTP is to make the target point approached by the trajectory. In PTP-PTP trajectory approximation, only the C-PTP parameters are needed. In PTP-CP trajectory approximation, if the PTP statement of trajectory approximation is followed by a LIN or CIRC statement, additional trajectory approximation parameters are required. The trajectory approximation in editing is only applicable to PTP-CP trajectory approximation. This parameter can be used to define the earliest time to start trajectory approximation. (2) Movement mode LIN When the movement mode is LIN, the robot’s movement programming form is: LIN target point . There are three types of target points: POS, E6POS, and FRAME. If all components of the target point are not given, the controller applies the value of the previous position to the missing components. In a POS or E6POS type target point, the state and direction data of the angle will be ignored in LIN movement (and CIRC movement), and the coordinate value is based on the base coordinate system (BASE). The trajectory approximation parameter makes the target point approached by the trajectory, and at the same time, this parameter is used to define the earliest time to start trajectory approximation. (3) CIRC operation mode
When the motion mode is CIRC, the programming statement is in the form of: CIRC auxiliary point, target point .
Among them, there are three types of auxiliary points: POS, E6POS, and FRAME. If all the components of the auxiliary point are not given, the controller will apply the value of the previous position to the missing components. The attitude angle, state, and data within an auxiliary point are ignored in principle. Trajectory approximation cannot be performed for auxiliary points, and the point is always accurately moved to. The coordinate values of the auxiliary points are based on the base coordinate system (BASE).
The center angle is the total angle of the circular motion, which can extend the motion beyond the programmed target point or shorten the stroke.
The trajectory approach parameter allows the target point to be approached by the trajectory, and this parameter is used to define the earliest time to start trajectory approximation.
2 Operation steps for absolute motion programming
①First, load the program into the editor in expert mode with the help of the open key.
② Check, apply or reinitialize the motion programming and setting values: tools ($TOOL and $LOAD); base coordinate settings ($BASE); robot guidance type or external tool ($IPO_MODE); acceleration; speed; possibly also trajectory approach distance; possibly also posture guidance settings.
③ Create a motion instruction consisting of the following parts:
❶ Motion mode (PTP, LIN, CIRC)
❷ Target point (and auxiliary point when using CIRC)
❸ When using CIRC, there may also be a center angle (CA)
❹ Activate trajectory approach (C_PTP, C_DIS, C_ORI, C_VEL)
④ Return to point 3 when re-moving
⑤ Close the editor and save