Reply To: Assembly experience RE: Niryo One v2.0 robot2018-11-30T05:02:13+00:00

Forums Niryo One Showcase your Niryo One project Assembly experience RE: Niryo One v2.0 robot Reply To: Assembly experience RE: Niryo One v2.0 robot

duck
Participant
Post count: 39

Hello everyone,

I would like to provide some additional information regarding my recent assembly of a Niryo One v2.0 robot.

The comments, questions and observations below are intended for the staff at Niryo, however I thought it might be beneficial to post them on the forums to see if they might stimulate additional advice from others who have assembled a Niryo One robot, as well as to serve as reference to those of you who may considering assembly of a robot in the future.

QUESTIONS

(1) XL-430 Servo Motor for Axis 4: Is it ok to run wires through center or is there a particular reason why the video shows the wires being run from one side? I found it difficult given the length of the wires I was supplied.

Axis 4 motor cables

(2) The 3-conductor cable that connects to XL-430 Motor Axis 5 in the v2.0 robot kit that I received did not include the Spiral Wire Wrap Tube around the end of the cable that was shown in the assembly video for Step 4. The three wires in this cable are very thin gauge and might be susceptible to damage during normal operation. Did Niryo decide that the protective covering was unnecessary? Is it advisable to cover these wires to prevent damage?

(3) Would AWG #20 gauge wires be better as replacement for the two AWG #18 gauge wires in the CAN bus in terms of providing a more secure connection and supporting the voltage/amperage requirements of the stepper motors?

I love the addition of the Molex connectors in the main cable harness in terms of easing disassembly and repair of the robot compared to the single cable harness without any intermediate connectors, but I discovered a continuity problem arising from the addition of these connectors that appears to demonstrate a basic issue regarding the gauge of wires being used for the CAN bus.

Two of the four wires in the CAN bus appear to be a thicker AWG #18 gauge. If AWG #18 gauge wire is required to drive the voltage and amperage requirements of the stepper motors that are connected to the CAN bus, it may be advisable to consider alternative replacements for both the Molex and JST connectors.

In my review of the specifications of both the JST XHP-4 and Molex Micro-Fit 43025 series connectors used in the CAN bus of the Niryo One v2.0 robot neither of these connectors support AWG #18 gauge wire. The upper limit for the Molex connector is AWG #20 and the JST XH connectors are only rated for AWS #22. The problem seems to be that it is very difficult to secure a thicker gauge wire to the pins even if one were using the manufacturer’s specialized tool. It might be possible for Niryo to solder the wires to the pins to add strength and assure connectivity, but these connectors were not necessarily built with higher amperage and thicker wires/insulation in mind.

In the case of the 2.0 robot that I assembled, I found that one of the wires had come detached from the female socket of the Molex connector and it was impossible to remove the socket using available tools, so I decided to devise an expedient (albeit not ideal) workaround by running a new wire from one of the pins on the JST connector.

Debug Axis 3 motor connection 1

Debug Axis 3 motor connection 2

I discovered that it wasn’t possible to insert into the JST connector an AWG #18 gauge wire because the insulation of the wire that I had was a bit thicker than what Niryo had used and I didn’t have any wire with thinner insulation available. I ended up running an AWG #20 gauge wire to the JST XHP-4 connector and crimping the detached wire directly to this new wire inside the aluminum tube between the Elbow and Shoulder. This defeats the beauty of being able to detach the Molex connectors for disassembly and repair, but it works for now.

I will consider in the future whether I should purchase a depinning tool so I can take the socket that detached from the wire out of the Molex connector and use the connector instead of my rather crude workaround.

(4) How are the Gripper tools supposed to be electrically connected to the XL-320 bus? I had this dilemma months ago when I setup a Niryo One v1.x robot and ended up removing the three-conductor 12cm cable from Gripper 2, using male Break Away Headers to mate it with the female connector on the 12cm cable for Gripper 1 and connect the end to the open connector on the XL-320 for Axis 6.

XL-320 Gripper tool cables

A long (1-meter) 3-conductor cable (the cable with the dot marked ‘C’ in the photo below) is supplied with the kit, but I’m not sure that I fully understand it’s intended purpose. It appears to have a male JST RCY connector on one end and female JST RCY connector on the other.

BOM electrical 3

Is cable ‘C’ perhaps conceived as being used to run a tool from the XL-320 port on the back panel of the Drawer? I have connected the Vacuum Pump to this port on the back panel, but the 12cm cable is so short that the Vacuum Pump must be stood on one end in order to use it effectively and ends up toppling easily when the robot’s arm moves.

If this cable is intended to be used to connect Grippers and other tools, then it would make more sense if both ends were male JST RCY connectors; then the user could use it to directly connect two 12cm cables from the tools. It appears with the present configuration (unless I’m missing something) that the user must supply his/her own male-to-male 3-conductor JST RCY connection or devise a workaround like the male Break Away Headers that I am using. I would very much appreciate any advice Niryo staff or others could provide about best usage.

Are there perhaps other intended purposes for the 1-meter 3-conductor wire? How does Niryo advise that a user should connect the XL-320s on the Grippers and other tools to the robot?

COMMENTS/OBSERVATIONS

(1) SURFACES ON 3D-PRINTED PARTS

Key surfaces on several 3D parts may need some additional attention in terms of further refinement. Here are some specific examples:

A. The interface surfaces between the Base, Drawer and Air Routing parts. I found that in Step 5 when it came time to slide the Drawer into the Base that there were considerable issues that prevented smooth insertion, sliding, and closing. It was quite difficult to address these problems at this late stage in the assembly process. Though I realize that it adds complexity and reduces elegance, it might be advisable to consider attaching the Air Routing parts to the base and testing the insertion of the Drawer in Step 1 in order to make it much easier to deal with any work required to correct these 3D-printed surfaces before the Base is already full attached to the Shoulder.

B. The holes for the M8x90mm screws in the Arm Bottom and Elbow are very tight against these screws. I can appreciate that there might be issues if these holes were loose and movement was possible, but I wonder if it should be this difficult to insert the screws into these holes and whether the resulting friction during movement might cause later issues after extended operation of the robot.

C. The surfaces inside the Arm Top where the stepper motor for Axis 3 is attached appear to be significantly refined from the v1.x robot. I discovered some very difficult areas inside the Arm Top when I was diagnosing and repairing some issues with a v1.x robot, so I am happy to see these welcome improvements in the v2.0 robot.

D. I realize that the End Caps for Arm and the Elbow differ in that the former have slightly deeper collars that fit into the Shoulder but it is confusing to differentiate between which End Cap is intended for which location during the assembly process. These parts should probably either be made interchangeable (the same design) or should be marked somehow to make it more obvious which is intended for which location.

E. I had trouble getting the Main Support of the Gripper 1 tool to fit well with the Hand. I ended up sanding the surfaces of the Main Support, but I wonder if there might be some ways to improve the interface of these surfaces to make it easier to switch tools in and out. I think that this is a nifty solution using 3D-printed materials to make a easily interchangeable structural connection, however bending the Hand to get the Main Support of the Gripper to mount troubles me (when I first attempted it, I was very worried about breaking the Hand and other parts of the robot).

F. I appreciate the improvement that Niryo made to Gripper 1 between v1.x and v2.0 (on the left and right respectively in the photo below). The small steel bar (labeled “Steal”) on which the two Clamps slide is a nice improvement to the ease of movement and sturdiness of this tool.

Gripper 1 v1.x lvs v2.0

(2) SCREWS

A diagram showing where the various types of screws go in each Step would be very useful. It’s especially difficult to ascertain whether a M3x10 or an M3x16 is being used in various sequences in the assembly videos. There are also several places in which M2 screws are used that one needs to be careful not to mistakenly use an M3 screw. I didn’t run into any problems with the screws related to the XL-430 motors but that was an area where I paid very close attention and some diagrams might also be useful.

(3) PARTS MISSING FROM DIAGRAMS

I noticed several places where parts used in the assembly videos where missing from the diagrams in the Google Slides.

A. The End Cap (2x) for Elbow are missing from the diagram for Step 4 [1].

B. The individual sections of CAN and XL cable harness that is needed for Steps 1-4 is not shown in the diagrams [1]. This should probably be much more carefully delineated since when the kit arrived they were all strung together in a single assembly with the various Molex connectors joined.

CAN and XL cable harness

C. The diagram for Step 5 shows that only one M3 Brake Nut is required when in fact 3 are used in the sequences shown in the video. [1]

D. The number of M3x10mm and M3x16mm used in sequences in the video for Step 5 does not appear to exactly match what is called for in the diagram for Step 5. I found one M3x10mm screw and two M3x16mm screws remaining after I completed Step 5.

E. The diagram for Gripper 1 appears to be missing M3x5mm (2x) screws needed to secure the XL-320 to the G1_MainSupport [2]. I tried using M3x8mm screws as shown on the diagram, but they are two long and end up obstructing full movement of the G1_ClampRight. I haven’t been able to find a good source online or locally for M3x5mm screws with hex heads. [2]

[1] missing from diagram, but included in shipment.
[2] missing from diagram and not included in shipment.

F. There is only a single steel bar (labeled incorrectly as “Steal”, but should be “Steel”) on the assembly diagram but the diagram has two pieces listed.

It may be advisable for Niryo to supply a small amount of spares for each of the various lengths of M3 screws, as well as the smaller Brake Nuts and Bearings. The Bearings should probably be packed separately from the screws and other parts in bubble wrap to prevent damage and confusion.

The housing cover of the one Bearings that I received had become dented and another had become lodged inside the CouplingShaft for the BlueMotor and I didn’t discover it until I completed Step 4. As noted in my previous post, I am grateful to the staff at Niryo for promptly shipping me a replacement.

damaged 6x19x6mm bearing

(4) USER-SUPPLIED TOOLS

I noticed that the v2.0 assembly videos no longer make use of a hammer (I recall several instances in the v1.0 videos where a hammer was used). The v2.0 videos do make use of a wrench in several places to fit Bearings and other parts into tight sockets on 3D-printed parts. This evolution reflects a certain refinement in the design of the Niryo One robot through this update. I hesitate to take a hammer to 3D printed parts because I am afraid of breaking them and know that it takes considerable time to reprint them.

The 2.5mm ball end hex key that is included with the tools in the v2.0 robot kit is much easier to use than the standard hex key that I recall was used in the v1.x videos.

I found that the kit included more tools than I needed; for example, it almost doesn’t seem necessary to include the Phillips head screwdriver and it wasn’t especially well suited to the screws for the servo motors and their couplings, so I used my own tools. It might be a good idea for Niryo to devise a video introduction of the installation process or some written instructions that alert people who order the kit that they need to prepare several tools and supplies.

A. I didn’t have any grease on hand and didn’t see any general advice from Niryo about whether any particular type was required, so I purchased a small tub of all-purpose grease (essentially the grease that is commonly used for bicycles or automotive applications).

B. A wrench should be used judiciously in inserting some of the tighter fitting bearings, etc. The user should be warned that 3D parts may be more fragile than they appear due the fact that they are not completely solid (the infill ratios used in printing the parts mean that there are empty spaces internally even with parts that appear completely solid).

C. A set of Phillips head and flat-blade precision screwdrivers is in my mind a necessity. I found that the Phillips head screwdriver included with the kit was too big to use with some of the smaller screws (e.g. for mounting XL-320 and XL-430 motors and couplings). There are several places in the process where a thin flat-blade screwdriver is needed (e.g. holding the M4 Brake Nut while screwing the M4 screw that keeps the aluminum tube secured to the Arm Bottom in Step 2).

D. A 1-1/2” putty knife and large flat-blade screwdriver in case removal of the torsion spring inside the Shoulder is necessary.

E. Wire cutters or finger nail clippers, sand paper, nail files and other manual cutters and abrasives to refine surfaces of 3D printed parts. A small Phillips head screwdriver also came in useful to remove obstructions in some of the holes for screws. Canned air and wet towels are also useful for removing debris after refining surfaces.

F. Needle nose pliers or tweezers to mount small screws and other parts more easily during assembly.

G. Calipers and/or a metric ruler to measure parts (e.g. there are bearings of various sizes that are sometimes difficult to differentiate between; the length of M3 screws used in particular places in the assembly can also be confusing and bears careful examination by the user during the assembly process).

extra tools that I used

(5) MISCELLANEOUS

In Step 2, I would recommend changing the sequence order slightly. Greasing the Arm Bottom and Torsion Spring before affixing the belt on the Arm Bottom ended up meaning I got grease all over my hands and on the Belt, Arm Bottom, and other parts. I would suggest waiting until after the Belt is affixed to the Arm Bottom before applying grease.

I am sorry that I made this post so long winded, but I hope that it will be of use to Niryo and to others and, as always, look forward to comments and questions from others.

All of the photos shown above as well as several others and annotations related to my assembly of the v2.0 robot are available in this Google Drive directory. If you are logged into Google when you view the directory, you should be able to post comments and questions on particular details in the photos.