check_position_condition_rel (Auto Mode)

This section explains how to use check_position_condition_rel during Auto (Run) operations to check whether the relative position of a specific axis is within the defined range with respect to a given target position.

It can be used in repetitive conditions (while or if statements) to monitor real-time positional limits. This function is particularly useful for verifying approach tolerances, alignment checks, and motion completion.

Typical usage

• Verify that the robot’s TCP is within a defined relative position range before proceeding with the next task.

• Monitor position deviations during automated tasks, ensuring the robot stays within safety limits.

• Combine with check_force_condition to implement hybrid position–force logic in control loops.

• Useful in processes like insertion, assembly, or surface following.

Note

• The function evaluates the relative displacement of the current position (TCP) from the provided reference pose (fTargetPos) along the given axis (eForceAxis).

• When using COORDINATE_SYSTEM_TOOL, the reference pose (fTargetPos) should be in the BASE coordinate system.

• If absolute position conditions are needed, use check_position_condition_abs instead.

Example: Relative Position Verification During Automated Motion

#include "DRFLEx.h"
#include <cstdio>
using namespace DRAFramework;

int main() {
    CDRFLEx drfl;

    // Preconditions:
    // - Auto mode active
    // - Servo ON

    // Define target position (in TOOL frame)
    float targetPos[6] = {400.f, 300.f, 500.f, 0.f, 180.f, 0.f};

    // 1) Move robot to target position
    drfl.movel(targetPos, (float[2]){80.f, 30.f}, (float[2]){200.f, 100.f});
    drfl.mwait();

    // 2) Check if the current Z-position is within a range of ±5 mm of target
    bool condition = drfl.check_position_condition_rel(FORCE_AXIS_Z, -5.f, 5.f, targetPos, COORDINATE_SYSTEM_TOOL);

    if (condition) {
        printf("Relative Z-position condition satisfied.\n");
    } else {
        printf("Relative Z-position condition not met.\n");
    }

    return 0;
}

This example demonstrates checking the relative position of the robot’s TCP (along the Z-axis) against a defined target pose. The condition is checked within a specified range (±5 mm) relative to the target pose.

Tips

• Use check_position_condition_rel() to ensure precise positioning during automated tasks, especially for approaching or aligning tasks.

• In combination with hybrid control, monitor both position and force to ensure safe and efficient task execution.

• Use short ranges for fine adjustments and broader ranges for coarse movements.

• Call this function inside control loops for continuous monitoring and decision-making.