Structure

Before the MicroChallenge 

The instructors need to know basic electrical and mechanical safety to host this MicroChallenge.

• Collect information of students who will participate in the challenge, and create groups where the participants’ abilities compliment each other. We used DISC profiling. 
• Organise meetings for teachers to discuss upcoming challenge week. 
• Organise an online meeting for students to meet the rest of their team. They should have ice-breakers activities, f.ex. find things they have in common, and decide upon a team name.

Assign homework to the students, have them take an online beginner course in robot control. We used the free UR e-Series Core Track   

Workspace preparation:  

• Assign work areas for the students’ groups with offloading areas for tools and equipment. 
• Mount a gripper to each robot, fasten the work piece tray to the worktable and prepare an adequate amount of work pieces (Link to github repository). (We used 3x3x3 pieces per robot.) 
• Mount a proximity sensor so that the robot can detect if it currently is holding a plastic object. The sensor could be either integrated with the gripper or placed in the work area.  
• Gather the required materials and tools needed for the students to be able to perform the tasks in the MicroChallenge.
• Prepare an example of a wiring cabinet and provide schematics [hyperlink to 3.5 Electrical_documentation.pdf].
• The advantage of these being prepared in advance is that the students can start working with the practical installation immediately. Having a shared, clear plan also makes it easier to guide the students when questions come up.  
• As we used a laser curtain, we provided a steel frame. The students then tap and thread the holes for mounting the sensors into the frame. [Hyperlink to 3.5 Light_curtain.zip]

During the MicroChallenge

Some of the tasks that are part of this MicroChallenge are dangerous and therefore at least one of the instructors need to be responsible of assessing the electrical safety of the students wiring work. The instructors also need to make sure the students always use the required personal protective equipment when drilling holes for mounting the equipment.

The first task for the students is to familiarize themselves with the robot. Since they should have taken the online training beforehand it should be quite straightforward to get the robot to move around.

When they have the robot running, the students divide themselves between the various practical tasks of wiring power to the cabinet, mounting the sensors to the metal frame and running signal wire according to the schematic. These tasks are intentionally pre-planned and practical so that they can be started on at once and in parallel.

When the equipment is installed and properly labeled the students can experiment with the different ways the robot can be made to react when the safety curtain is being triggered. The need to decide if it should slow down, pause, stop, or just avoid certain areas. Their decision and motivation are logged and become part of their risk-analysis documentation.

Depending on team decisions, two teams that share the same robot may end up deciding that they both need to use the same safety input. If this happens, they need to connect their light curtains in series. This is covered in the Wednesday lecture 3.7 Talking in the workshop: Combining safety systems and 3.7 topography_light_curtain.pdf (HYPERLINK). (If each team has access to a robot each, this contingency will not be needed.)

After they have completed their safety improvements and documentation there is secondary task available to the teams. Using any remaining time, they should attempt to improve to the efficiency of the robot program using the capacitive sensor in the gripper. Note that this is NOT an approved safety sensor and should not be relied on to increase the safety of the installation.