RoboThespian Maintenance

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RoboThespian >> RoboThespian Troubleshooting >> Maintenance

Introduction

Keep an eye on small problems and attend to them before they become big ones.

Any system with moving parts is subject to wear and will eventually need to be repaired or replaced, RoboThespian has been designed to operate with the minimum of maintenance and this wiki is here to help you address problems quickly and efficiently when they do arise.

Make a daily visual check for signs of wear or damage, loose screws or fittings and broken or worn cables.

If you suspect an actuator is not performing correctly run the self test routine in the admin section - Self Test

Lubrication

DON'T USE OIL SPRAYS

Oil sprays like WD40 or similar products will damage rubber seals and plastic parts.

Finger joints may need an occasional, (3-6 months) addition of PTFE or Silicone lubricant spray to keep them free moving. Also apply to the finger strings where they enter / exit the finger segments.

The brush (spiral) springs on the shoulders require regular lubrication - see RoboThespian Shoulder Brush Spring Lubrication

Other joints use self lubricating polymer bearings and should not need additional treatment.

For the arm twist movement brass bevel gears are used, which require no lubrication.

Motor gears have induction hardened teeth and have a generous amount of tough, long-lasting open gear lubricant applied which should be fine for 12 months or more. We suggest checking after six months and if required apply a little more - Tufgear universal lubricant - http://uk.rs-online.com/web/p/industrial-lubricants/3888465/

Compressed Air Supply

Follow the manufacturer's maintenance and troubleshooting instructions as supplied with the compressor.

The quality of your compressed air supply is crucial, if you are using a silent type compressor with an oil reservoir, (Jun Air Model 6-25 or similar), make sure that it is kept cool and runs below 50% duty cycle. If you see any signs of oil contamination in tubing (discoloured tubes etc), replace the filter element in the filter regulator unit as per the compressor instructions.

Oil contamination will cause valve failure, a complete set of valves costs around 1000 GBP Oil contamination will also damage air muscle membranes leading to premature failure.

Engineered Arts now recommend an oil less compressor rated at 100% duty cycle:
Free Air Displacement at 8 Bar 38 l/min.

  • Jun Air Model OF302-25B Noise level dB(A)1m 65
  • Jun Air Model OF302-25M with acoustic cabinet Noise level dB(A)1m 47

Regularly check for and drain any condensate - see Compressor - Draining Condensate

High Wear Parts

Shoulder cables, (Shoulder Roll Axis, AKA Shoulder Out). Depending on usage these can wear through every 6 - 18 months spares are supplied with your robot, and additional replacements can be obtained from Engineered Arts Ltd.

Head USB cable. Depending on usage these can also wear every 9 - 18 months. One spare is supplied with your robot and additional replacements can be obtained from Engineered Arts Ltd.

Finger Strings, we have strived to find the most reliable 'tendon' material for operating the fingers. Our current choice is Dyneema fibre. It is a high strength low friction material. Spare Dyneema is supplied with your robot or can be requested from Engineered Arts Ltd.

Other Parts That May Fail After Arduous or Extended Use

  • Air Muscles
  • Jaw Servo
    • Since mid 2012 RoboThespian uses JR PROPO MPH81G servos for the jaw with non-contact position sensing for longer life, and have not had a failure yet.

Minimising Wear And Tear

The type of movement your robot makes and the rate of movement repetition will have a big effect on component life. Here are some tips for minimising mechanical wear and tear.

Don't Move When Nobody Is Watching

Programming a background routine with a lot of movement is a bad idea, keep background movement to eye movements and a few small head movements.

Avoid High Speed And Sudden Changes Of Direction

Sudden moves and fast oscillations will increase wear, use this kind of movement for occasional dramatic effect only.