Mimic Platform Project

Shared with express permission of Curtis Berlinguette Research group

In my first few months at Ada I noticed that 24/7 operation was severely limiting our hardware development work. I proposed that we build a duplicate hardware platform out of our back-up modules which would allow us to iterate on hardware design without sacrificing system up-time.

Design Process

Problem Definition - Requirements Constraints and Goals

Requirements and Constraints

• Uses existing back-up arm as the base platform for the project.

  • The arm will need to be restored to working functionality.

  • Runs the current software control environment of the primary Ada robot

• Provides specified utilities (air, vacuum, PWM servomotor control, DC motor control).

  • Integrates control over those utilities into the primary software interface.

• System does not harm users or equipment (see hazards and mitigations).

Goals

• System is accessible for remote control.

• Physical controls over the utilities which allow for manual control.

Main Arm Setup

The base of the Ada robot consists of a SCARA manipulator arm and heavy duty platform with standardized mounting holes. Multiple units of this system were provided to us by the vendor. My first task was to contact the vendor and conduct hardware setup of our backup unit as well as put together our existing Python control environment on a dedicated control terminal.

Manual Control Boxes

After pitching this project one consistent feedback item was a desire for an integrated utilities control system. Previously we had been designing a separate actuation system for each and every Ada hardware module. Some users were even 'borrowing' vacuum or air supply lines from the Ada robot to test their modules during system downtime. It was essential that the mimic platform package these utilities alongside the primary robot manipulation arm. From personal experience I was also aware of how important manual control is for sketching out movement routines. Therefore I set out to make utility supply control panels which could be controlled programmatically and manually.

I created the following instructional videos to supplement a user guide I had written. They demonstrate the functionality of the final iteration of each utility box:

Pressurized Air Utility Box

Vacuum Utility Box

Motor Utility Box

Hazard and Mitigations

I conducted a risk assessment in order to identify and address the safety challenges posed by this project. I created the table below and spent ~1 hour filling it out (various items omitted for brevity). I then scheduled a meeting with various project stakeholders (co-workers) and collected additional items and comments. I identified the priority hazards to address and implemented mitigations into my design.

Risk Assessment Matrix

Hazard	Impact	Likelihood	Priority
A human is pinched by fixture movement	0.80	0.75	0.60
A human is shocked by a motor controller (<60V)	0.30	0.50	0.15
Glassware is shattered by robot movement	0.05	1.00	0.05
A human is shocked by the N9 arm (>100V)	0.90	0.05	0.045

Mitigations

• A human is pinched by fixture movement

  • Implemented emergency stop buttons within arms reach of all points around the station. This will allow operators to stop movement and prevent further injury if something goes wrong.

  • Implemented panel-mounted lights to indicate to user status of utility box operation. This prevents instances of unexpected movement from fixtures which use the utility boxes.

• A human is shocked by a motor controller

  • Labels are supplied to direct user towards a safe (below involuntary movement threshold) voltage range when configuring voltage settings.

  • Lab safety procedures and best practices for electricity are reviewed with potential users (removal of metal jewelry, check device temperature, designing an electrical fixture).

• Glassware is shattered by robot movement

  • A plastic hazardous materials container and counter brush are provided within the mimic platform workspace.

Outcomes

The 'first customer' of the mimic platform was this uncapping/capping routine which had previously been in and out of development for over a year due to reliability issues. Using the mimic platform I was able to iterate on the existing routine and clamp design without concern for blocking system uptime. This gave me the freedom to run extended reliability tests. I was able to demonstrate >100 consecutive successful cap/uncap operations which met the established reliability requirements of the group.

Secondary Benefits

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