Skill Assistance with Robot for Manual Welding

-SkillAssist-

by Mustafa Suphi Erden

Marie Curie Intra-European Fellowship, Project No: 297857

 

 

Host Institute:

Learning Algorithms and Systems Laboratory (LASA), École Polytechnique Fédérale de Lausanne

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Main Results Achieved

The below four items of results were achieved with the above described experiments. The number of subjects who participated in each experiment is indicated in the tables and the figure caption given below. In the airbrush experiments the subjects performed straight line painting with their dominant and non-dominant hands. In the welding experiments the professional and novice welders performed Tungsten Inert Gas (TIG) welding on the connecting edges of two stainless steel plates. In all cases the subjects were left free to orient their arms and body as they found convenient. They were instructed to aim at the best performance they could.

  1. While doing airbrush painting, subjects applied larger damping with their dominant hands in the direction perpendicular to the painting line (Table 1). Robotic assistance by compensating damping in the directions perpendicular to the painting line improved painting quality (Fig. 4).
  2. Table 1: Average hand-impedance parameters while subjects performed airbrush painting in y direction.

    (a)(b)

    Fig. 4: Sample painting with non-dominant hand (a) without and (b) with robotic assistance.

  3. Professional welders applied larger impedance (rate-hardness) compared to novice welders. The most significant difference occurred in the damping parameter in the direction perpendicular to the welding line on the metal plate (Table 2).
  4. Table 2: Average hand-impedance measures while subjects performed TIG welding with the robot.

  5. Impedance compensation type robotic assistance improved welding quality of the novice welders by significantly decreasing the position variation of the torch. Answers to user questionnaire showed that all novice welders and most of the professional welders found welding with robotic assistance easier and more successful than welding without the robot.
  6. Table 3: Average ratings of the responses of novice and professional welders to the user questionnaire.

  7. With the training system, the position variations of the novice welders decreased when they received immediate notice feedback for the hand vibrations. The most significant decrease occurred when the notice feedback was in the form of a visual alarm (flashing LED) compared to an audio alarm (beep sound) (Fig. 5).
  8. Fig. 5: Position variations of the tip of the welding torch in the presence of no alarms, sound alarms, and light alarms. Asterisk indicates statistically significant difference. 12 novice and 5 professional welders participated.