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- Platform for payload
- Is there a kind of Payload rack design in place?
- YES see Brey's Platform design
- Is there a kind of Payload rack design in place?
- Buying Extra Hardware
- Where can we order more fasteners?
- Part numbers have been updated on our BOM for all M6 screws & extrusions
- Latest Bill of Materials is posted here
- Where can we order more fasteners?
- Wheel brackets
- They feel too tight
- It's hard to place the fasteners, they must be slid into position blindly
- Caster Wheels
- Unclear how many screws
- Unclear position of screws
- Unclear if it needs 1 washer per screw?
- Wheel pulley:
- It's easily broken if inserted in the wrong side Note: Vijay has USA wheels + Asia pulleys combo (check tightness) It was easy to plug in the correct side but too late
- Not clear which side of wheel has "deep dish"
- User may hesitate before gluing permanently
- Remind users to glue the pulley
- (doesn’t matter if the finger breaks)
- Not clear if fingers are structurally integral
- If it breaks, that's OK but user does not know this
- Encoders:
- Were not sent with header pins included
- Header pin spec should be communicated if users buy their own
- CAD model does not show the magnet
- Instructions don't explain placement of magnet, poles, etc.
- There is a video but no guarantee user will discover it
- Motor Pulley:
- Not clear how the pulley goes on the motor shaft.
- Need to refer to video with magnet & encoders & pulley together
- If pulley is inserted backwards, it will be broken
- Not clear how the pulley goes on the motor shaft.
- Motor spacer:
- It's included but not necessary
- Need to verify motor shaft length (by parts variants) to include or not
- Need to provide instruction about it
- Wheel Assembly
- There is binding/friction when he tightens the M8 screw
- We need to check root cause of this binding
- Comparison
- Turtlebot assembly, 1 year back by same user (software eng)
- Kids can also assemble successfully
- Had more subassemblies pre-built in the kit
- fairly easy overall
- Pros/cons of self-build for all pieces of SCUTTLE:
- Confident in knowledge of the system after having built the unit
- Test of Electronics
- Seeking an automated test to verify all devices connected properly
- PDF Manual disbursement
- Kit should give access to manual right away, perhaps a postcard in the box with hyperlink
- HDMI connection
- experienced user prefers to connect to monitor for setup
- HDMI or MICRO-HDMI would be needed.
- Minor Software Errors
- We could make corrections in the github directly
- Need to show the process for user to "git pull" updates for their existing image
- Encoders Spacing
- Customer unaware of spec (too close/too far)?
- Variants of (motor, motor spacer, wheel pulley, and encoder bracket) can stack up tolerances. Must document variations & share.
- Encoders test
- User trying out /dev/i2c to discover encoders - is it a valid method?
- Enable i2C bus if not enabled (this is in manual, but can we put somewhere else?)
- Encoders Error
- right wheel & left wheel directionality: need troubleshooting resource
- TRY:
- see Beagle version of wiring guide for details about i2c bus
- verify soldering is bridged, per wiring guide
- verify encoder cables are unique and connected per wiring guide
- ACTION: We need to update Pi wiring guide with matching details.
- Accessing the HDMI ports:
- HDMI ports are hard to reach on Pi
- If the user slides Pi bracket over for access, it pulls the cord from the
- suggested CM: Include slightly longer dupont cables.
- When running L1_motors.py, I see both wheels turning forward but the right wheel does not move backward. It moves forward that means the power connections are ok.
-
The below condition is possible for motor driver for a given wheel:
Positive terminal Negative terminal Goal result 3.3v NC DRIVING FWD SUCCESS 0v NC DRIVING REVERSE FAILED -
Another Common Failure Mode is:
- Ground signal wire is disconnected (this agrees with diagram) AND 18awg ground (source voltage) does NOT come from battery.
- In this case, there is no common ground between the motor driver and Beagle, therefore the 3.3v signals have no reference.
- Ground signal wire is disconnected (this agrees with diagram) AND 18awg ground (source voltage) does NOT come from battery.
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- Corner Blocks loosen over time
- Engineering notes: A torque spec should be issued, with instructions on how to achieve such torque without an instrument.
- Barriers: Torque for aluminum corner brackets should be probably 10x higher than the wheel brackets. So, two different torques for one kind of screw could be a pitfall. The lock washer will be considered, or alternately making hex-shaped heads on corner brackets (to allow allen wrench) and keep phillips heads on the wheel brackets (disallow high torque, which will crush the plastic).
- Caster wheels float if chassis is non-level
- In theory this will not affect tracking. It can affect tracking if: a) the robot has no payload and the movements are slow, b) the rear wheel also has a chance to float.
- SCUTTLE team should make a video to describe this issue in depth
- Wish to check flatness of frame before final assembly.
- drop-in nuts will be replaced by slide-in nuts for the wheel bracket to help alignment
- next version of wheel brackets will have fewer nuts
- a version of the rod brackets are available with twist-in option (but the strength is lower)
- Height of the wheel brackets is flush with frame, impacting ease of assembly
- team needs clarification from customer. (can we have a photo for this issue?)
- Camera bracket is weak
- let's see what was the failure mode and try to enhance strength.
- video instructions MIGHT help, so user doesnt stress the bracket the wrong way. We could issue this with QR code attached to the parts.
- really we will have trouble if customer does not have easy access to 3D printer. The very least we could do is offer lists of links to reputable, affordable printing companies in each country.