In the field of human-robot collaboration (HRC), the speed and separation monitoring (SSM) collaboration have attracted much attention owing to its non-contact safety strategy. 3D sensing applications are currently of interest for industrial automation technology and are considered to be a promising method for maximizing the efficiency of SSM. However, little attention has been given to the runaway space of the robot or the potential contact due to the foreseeable misuse of the operator. In this study, experiments are conducted using a radar system as an example of a 3D safety-related sensor, and battery assembly scenarios are carried out for the comparison. In the experiment, two different orientations of the robot are tested, considering the potential runaway motion of the robot. Also, the maximum permissible speed of the robot is calculated by geometrical transfer energy, which is based on effective mass and the velocity of the manipulator and human injury criteria. From the experimental results, it is evident that it is better to avoid placing the vertical articulated robot in front of the operator from the perspective of minimizing the effect of runaway motion into the safety distance. Finally, the proposed framework of speed limitation is thought to be an effective method to link SSM and power and force limiting safety function.
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