XV-11 bumper design and climbing

[craigbla]

I tried adding 3/8" shims under the speaker stands that Neato is climbing up on but it still was not enough.

When I look at the bumper from the side it seems that there is enough vertical play in the bumper to allow it to ride up on objects(especially with rounded edges) more than I would like. Neato is hitting a low price point so I understand that there are limits to what they can do but I think it would help it they could reduce the vertical play in the bumper so it would engage more often and not ride up objects as much.

[glnc222]

I have materials on hand to demonstrate adding a skirt to the bumper, will see how that works. Could be the assumption that raising furniture was best is wrong, and one should lower the bumper instead. I don't think the vertical play in it is enough to make much difference -- needs more depression. You can't really do much about that vertical play, either, without radical changes to the structure, to insure the bumper moves -- without a very high price.

[glnc222]

bumper tests for climbing problems

Pictures of furniture where Neato climbing over caused navigation problems, traps, terminating or disrupting cleaning etc. This complements particular furniture styles causing the opposite problem of overhead pinch traps.
Only certain styles present problems to Neato navigation.

(thread: Vorwerk VR100 Neato? tries to climb tubular chrome chairs. http://www.robotreviews.com/chat/viewtopic.php?f=20&t=16549


other examples:





One solution is to raise the furniture enough to trip the bumper. The top has to be over an inch above the foor. Deepening the bumper instead is shown in the
example below, attaching a1/4" oak board to the front of the bumper. (a previous mod for overhead traps is visible in extension on top, thoroughly proven)

bumper deepening test

It is difficult to attach a cover with velcro, as it must extend all across the front for enough glue hold, and be cured overnight. Double sided tape probably better, and over top wrap as shown (also benefits from proper curing; ideally attach with screws, but for warranty issues). velcro adds a lot of thickness.

In this instance the carpet is pile and the 5/8" thick furniture base sinks down a lot, so the bumper won't hit unless virtually brushing the top of the pile. Neato is sunk in the carpet as well, but short pile is not a problem itself. (another solution has been found to really deep pile, raising the front with bottom furniture gliders).

It is necessary to extend the sides as well as the front, as Neato is persistant and after bouncing off the front, will swipe rotating with the sides and succeed in climbing over. It probes for every weakness. Opening must be provided for the wall sensor, and needs to be thin not to interfere with closeness to walls.

The Neato's stance is slanted upwards slightly, and the bottom is beveled on sides as well as front to assist climbing obstacles. The bumper edge has to get farther down than may first appear. The beveling and slant looks more a factor than vertical play in the bumper, which doesn't seem much to me.

Now here is the potential problem -- not failing to climb things, but backing up (though of course, if you have floor transitions to climb that also becomes an issue). When in reverse the wheel torque adds to the suspension springs lifting the back and pointing the front down. This happens in tight spaces, and even shortens the Neato's length. With the bumper too close to the floor, this digs the bumper into the surface causing drag which traps the machine, at least as I tested it. Edge treatments and enhancements might make a difference, unknown. It got stuck after climbing up sideways onto the chair base it normally dusts off cleaning over it. Even were this prevented, some tight space backing up could prove a more severe trap than previously.

Possibly a less deep extension just enough to manage a certain environment might work, not interfering with backing, but would require testing.

Interesting to see the subtleties of navigating household floor spaces the designers had to handle. Even if there is some definitive solution, I would not expect it to come from the manufacturer, given the cosmetic changes that have been made in these products over years. Aesthetics plays a role in marketing requirements as well (and if they don't sell, you'll get nothing). If you really want it to work, have to do it yourself, tweaking the industry offerings, imho. Or you may just not have any of the problem types of furniture. Otherwise it just might not be suitable for everyone's needs. The process of improvement continues...

[craigbla]

I attached 8 round plastic/silicon? adhesive backed furniture pads to the bottom of the bumper where they would not interfere with the bumper motion.

This does trigger the bumper more often but as you have pointed out - the Neato is very diligent at turning and trying from a side angle where it will climb right up - DOH!

I think the missing piece is that I would need to do the same thing on the side bumpers and there is not enough space for anything but a very narrow extender - don't know what or how you would attach it.

[glnc222]

Piece of a wooden or plastic ruler taped, glued on the side. plastic sheeting, scavenged plastic box sections, thin wood boards, masonite and plastic clipboards. strip plastic moldings. duck tape, double sided tape, foam mounting tape (auto trim type strongest). Can't use the bottom of the bumper on the sides, a plate on the side is required.

Double sided tape should be applied to painted, not raw wood surfaces, for adequate hold.
Scotch double sided transparent tape works well on Neato plastic, with enough area. Once proven works, screws will be needed for longest durability.

Ideally you want a side plate extension to cover the bumper side surface up to the top with a glue strip all along the top back to front, so when the plate is pressed in at the bottom is a lever longer above the pivot edge, reducing pull at the top, increasing glue hold. Best completely cover the plate surface with double sided tape for strong forces of bumper contact. Also duck tape over the outside plate surface onto the Neato top for even more strength. Same treatment for the front of the bumper if needed. This is how the example shown in the picture here is constructed.

Raising furniture have to go beyond plastic bumpers, put 1/2" wood -- recess to hide, or paint. Push the Neato against it manually, doesn't damage, see the clearances.

Interesting source of plastic is old VHS video tape boxes, if you can find. Cuts with scissors.
Small ABS sheets: http://www.servocity.com/html/abs_sheets.html
Also Amazon's SmallParts.com.

[for the opposite problem of adding height to the bumper see "bumper mod question" http://www.robotreviews.com/chat/viewtopic.php?f=20&t=16761
and "overhead pinch trap" http://www.robotreviews.com/chat/viewtopic.php?f=20&t=15853&p=108543&hilit=overhead+pinch#p108543
The bent coathanger wire used there would work just as well for lowering the side bumpers. ]

[glnc222]

Example of plastic side plate addition extending bumper lower. 3/64" (1.2mm) plastic holds with transparent double sided tape only, operates bumper. Scrap piece not full size or shape.

example bumper side plate

Examples of bumper front edge mods others used -- the bottom trim plate has some room:

[craigbla]

That looks like it would do it - would be nice if there was an easy to remove/install replacement bumper with height adjustment.

[glnc222]

adjustable bumper mod

The existing bumper can be given adjustable height without replacing it. With the bent wire extension, instead of tape the vertical wires can be held under tops of flat head screws, say two on one side and one in the middle opposite side, tightened in the desired position.
Reverse this upward extension:


A fancier fitting would be a plastic strip with a wire groove, and a rotating cam section to the side of the wire to lock it in place with sideways pressure, for quick adjustment.

Plastic sheet extensions can be made adjustable by fastening with screws through vertical slots in the sheet.

If lowered bumpers work, though, I don't see the point of adjustment. That presumes they only work in certain places, implying constant fiddling. Better have another vac equipped for the one problem area. Matter of taste.

[glnc222]

effect of tilt moving backwards

Maximum tilt possible moving backwards shows how a bendable front bumper extension probably required. Sliding upwards would need rollers on the bottom edge. Wire loop types bendable inserting sideways ends in a plastic block or half a small hinge, or can thread rollers. Reveals subtleties of the case design, not as simple as first appears. It also seems that some navigation out of tight spaces depends on shortening length by flipping up the back this way, so some sort of blocking pin on the wheel arm rotation is not advised.

maximum tilt and bend required in bumper extension

Edit:
A hinged flap or wire at the bottom has mechanical problems: to flip up when the bumper tilts down as the Neato back flips up, the flap must extend a bit forward of the bumper and be hinged close to the bottom edge, at say a 45 degree angle. This prevents the bottom edge serving as a fulcrum for fastening the flap far up the front of the bumper, to resist inward turning in the intended low obstacle strikes. Fittings to block inward rotation of the flap would be bulky if not manufactured with suitable steel shapes in such a small size. Could be much easier to construct a vertically sliding flap. Spring loading is needed to keep pushed down.
Edit:
Just one way to get a low positioned hinge that might work is a short right angle piece like a screw extending back under the bumper edge, which would press upwards against the bottom surface when the flap is pressed inwards (and pull down on the hinge, requiring good attachment). When the flap is flipped up, this piece will protrude down so must be short. A vertical slide eliminates the need for a forward extension to get leverage on the flap as the Neato tilts, but is a harder fitting to make.
Edit:
Vertical slider simple with wire bail into vertical grooves on a plastic plate glued across the front. Cheaper plastic ABS sheets on ebay, used for auto interiors, will see how it works when materials arrive.

[glnc222]

trap reproduced

Neato stuck climbed onto 5/8" board

Neato climbed onto 5/8" laminate board and was stuck by excess friction with the sharp edge. Insufficient torque or traction to move on or off. Duplicates conditions of some scandinavian furniture legs. The bumper needs to deflect off these obstacles.

5/8" and 1/2" board fitting under bumper edge on carpet. The 5/8 will sink under weight or in small pieces like stands over time, so the target for bumper contacts is 1/2".

1/2" and 5/8" boards fitting under bumber on carpet

[glnc222]

Wire bumper fix demo
1/16" stainless steel wire or coat hanger wire appears to work with a layered plastic mounting. This minimum thickness required for stiffness. ABS plastic for auto work was used here, crinkle finish one side, since available in 15" sheets on ebay for a strip all the way across the front; only a center section is shown here. I don't intend to complete a full modification, just show one approach with fairly good promise, for anyone needing this for their scandinavian or designer furniture.
The wire cross piece could be covered with heat shrink tube or duck tape should softening be of use.

wire bumper assembly

Instead of carving grooves in thick plastic, a 1/16" backing is used and two 1/16" layers in blocks with gaps are glued to the backing -- here just with double sided transparent tape, adequate for testing. When satisfied, can be redone with crazy glue, gorilla glue, or epoxy (only certain glues work on plastic). A 1/8" gap is used for a loose fit around 1/16" wire, to obtain easy sliding. Ideally 1/8" plastic should be used for the blocks, to provide the smoothest possible bearing edge. Pre-gluing two 1/16" layers and smoothly cutting the edges may suffice, used here. Aluminum strips could also be used but won't glue as easily. Thin modeling wood won't have as hard a bearing surface, but painted might work, haven't tried.
Double sided tape is then applied to the entire blocked surface and attached to the front of the Neato bumper, positioning the wire bail at the proper distance.

bumper lowered by sliding wire bail

The wire slides up when Neato tilts moving backwards, to not obstruct the movement by digging in at the front.

wire bumper slid upwards with tilt

This extension is set to deflect the bumper off 1/2" wood resting on carpet, with the Neato slightly depressed into the surface. Note the wire extends up high on the bumper so glue hold at the top has leverage against the bottom edge fulcrum to withstand inward hits at the bottom, remaining stuck and depressing the bumper.

Performance
Deflection from 1/2" wood is shown in this brief video, as well as how the extension did not interfere with Neato's backing up tilted, at least in this case. Software V3.1 just released adds some of the backing motion. A lot of thorough testing might reveal further problems, I am leaving to others. Video: http://youtu.be/aRxCbdIg0C0
At the same time the extension appears to slide properly over obstructions which do not trap the Neato, such as a broad circular chair base, which caused a trap with a non-sliding extension -- in this brief video: http://youtu.be/7mx7dXHlA9s

Completion Required for Function
To work usefully additional wire loops must be added aside the center one shown, completely covering the front, and the sides of the bumper must also be treated -- else Neato will slide over obstacles turning. The sides may not require the sliding feature and can be treated just with plastic strips, if a gap is left at the front corner as needed to accommodate tilting. Extensive testing would reveal any need for sliding the side pieces.

Materials
No convenient source of this thickness stainless steel wire was found other than scavenging from a kitchen gadget "chef basket" -- the circular rim, providing only a couple feet (wildly different prices, cheapest http://www.amazon.com/gp/product/B004K719Y0/ref=oh_details_o00_s00_i00). Thinner wire available in jewelry supply, inadequate. Copper, aluminum, or brass rod is too soft in this thickness. Painted steel coat hanger wire best alternative -- generally obtained only from dry cleaning, as everyone uses superior plastic hangers.... [edit: also available on ebay, just found] Sources of materials not my specialty, so readers may know more.
Handling: harder steel wire this thick will not cut with electrical wire sheer cutters; a bolt cutter, such as on electrical crimp tools, can be used instead of the huge ones. Ends may need some filing finish. Dremel power cutters also suitable, or hacksaws.

boring details of sources
Smallparts.com has varied types of plastic, pricey, unfamiliar in all. Nylon is used for nuts and bolts. PC or polycarbonate is Lexan, used for cups and windows, very hard to cut. PP Polypropylene is a superior replacement for polystyrene used in threads for heavy duty upholstery cloth. Plexiglass or acrylic, along with lexan sheets are used for picture frames, available in hardware stores up to 1/4" -- expensive. Vinyl of course is everywhere, but seems to be expensive. 1/16" ABS is cheap and cuts with scissors, though a really straight cut requires a knife or saw. 1/8" won't cut with scissors. The 1/16" thickness was found inexpensive only in auto trim supply on ebay; 1/8" also at servocity. ABS is fairly flexible, but appears to work in this application, supported by Neato's bumper surface. Servocity.com sells it for robotics hobbies, just indicating suitability. Can be painted, too (paint usually needs a binder to stick to plastic; Krylon spray paint comes in a special plastic-ready line).


If anyone tries any of this bumper lowering, I hope they will post results for enjoyment of other Neato fans, and include lots of pictures (all this verbiage is just in case someone not into crafting things needs the info that was hard to obtain myself).

[glnc222]

All Wire, Plastic-Free Version
Thinner 18-20 guage wire or any metal bendable into bearing mounts -- paper clips -- for thicker steel bumper extension bail; duck tape on. On ebay you can see coat hanger wire even used for art work. Also available Amazon.

[glnc222]

design suggestion
There are hollow tubes up the inside of the front bumper for screws securing the bottom flashing. They might hold compression springs on plastic rods extending to a properly shaped bottom rail. The sides can just be lowered. So maybe not so expensive as the problem first appears.

Edit: A finished add on might be manufactured as a replacement for the bottom bumper trim, attaching with the same screws. Add integral 1/2" down extensions on the sides, and more holes and stuff on the front for an integral sliding piece. Interesting project for a 3D printer.

A variety of Mods for other cleaning problems at
http://www.robotreviews.com/chat/viewtopic.php?f=20&t=16475

[glnc222]

final suggestion

Edit: Neato announced a new higher priced "signiture" model at a trade show early March 2013. The minimal press report includes "a new floor-hugging vacuum design (though no specifics have been given)". Have to see if anything done for the designer furniture climbing problem. See thread http://www.robotreviews.com/chat/viewtopic.php?f=20&t=16891

The simplest way to redesign the bumper may be not any moveable addition, but adding vertical play to the entire bumper.

A vertically longer bumper face, extending the bottom lower half an inch, but capable of sliding the whole up as well as move horizontally and in and out. The existing vertical position is locked by the screwed on bottom flange sliding over a sill on the case bottom, and the top grab bar lip over the top of the bumper. Adding half an inch vertical play with a half inch deeper front face and bottom flange half an inch below the bottom of the case with a gap, loosening the top grab bar and the spring attachments. Some other means of securing the bumper around vertical posts would be needed -- the design problem. Photos of the bumper structure at viewtopic.php?f=20&t=16761

For a pivoting approach, the bumper could be pivoted at the rear, if some suspension could be made with horizontal play, no idea how. The whole bumper would bend up when pressed into the floor by the unit tilting.


modification

For a mod adding to the existing bumper as is, the sliding wire above can be simplified with similar pivoting at the rear sides. A single wire much thicker than coat hanger for stiffness, 3/32", all across under the front, could be attached in a pivot hole in the back of the sides. Like half a square lying under the front and bent around back under the sides 1/2" down, with vertical arms at the rear up to a pivot hole. A pin behind the vertical arms -- even inside the bumper -- would hold horizontal position. Not familiar those materials, maybe some sort of fence wire. A plastic molding of just the right shape for strength would work, but would seem easier to fix the whole bumper -- unless you have a 3D printer.

Edit: found parts: stainless steel 3/32 welding filler rod 36" -- only by the pound pack dozen+ on ebay
Single stainless threaded rod screw size 6-32 36": https://www.speedymetals.com/p-4836-6-32-ss-threaded-rod.aspx
Across the front could go into 1/4" thick plexiglass side plates -- a little thick but ....

Edit: better deal, so will try one -- maybe just the right shape will simplify.
Ebay single 3/32 stainless rod cheap company above http://www.ebay.com/itm/3-32-Diameter-304-Stainless-Steel-Round-48-Long-/160751376671?pt=LH_DefaultDomain_0&hash=item256d87591f

pivoting coat hanger version
Actually can be done with coat hanger wire. Neatest when attached to a side hole in the bumper, but can be pivoted at the top with a paperclip loop. Plastic side skirts needed. This can be simpler than the sliding version since extends all across in one piece, and moves easier. Makes the sides more convoluted though. Could use thinner wire than shown, as the front support loops cover the flex on front strikes and more can be used. The front wire can also be covered by a plastic sheet. When Neato tilts the front wires move away from the surface with this geometry.

Edit: I may show a more elegant all plastic version of this mechanism when I get to it. Nothing so far is fully satisfying. The pivot looks like the right mechanism, and getting a more finished look remains.

[glnc222]

pivoting plastic version

plastic bumper extension attached, engaging 1/2" board (missing bit of bottom corner trim to complete)

pivoting bumper extension when Neato tilted

The wall sensor must be uncovered even when tilted.

Rubbermaid drawer divider 15", for rounded corner braces

parts cut out of plastic (not shown 3/4" clear right angle wall corner protector, used to stiffen the front)

assembled plastic pieces

bottom view bumper side, flange removed

[edit] actually the left side of the screw post is better than right side with arrow shown. Note side of bumper will move inwards flush with the block, and to the left when hit on the front of the vacuum. 3/4" forwards of the back edge of the bumper is the best pivot position, will be behind the post.


A pivot can be glued to the outside without drilling the case, protruding a bit compared to countersunk flathead screws. Pivot at height where back curve of front begins as top rotates back, bottom out slightly, for snug fit to front.

[glnc222]

Most Attractive Version

Not showing one built, but I think the best looking would combine the metal wire bail of the sliding version with the pivoting mechanism, so just a one inch strip of plastic on the front and sides would do, with the wire sections glued into the plastic as fitted in the sliding version but fixed.

Wire under both front and sides, forming a continuous wire bail around the bottom. The side pieces would be pivoted at their rear top corner similar to the larger pivoting plastic version, but lower; same stopping block strip to hold it up. Greater stiffness of the wire compared to the plastic allows much lower coverage of the bumper faces and handles clearing the wall sensor.

Don't need it myself right now, so proof is left to the student as they say.

This combo would also be easier to construct than the bulky plastic version with so many pieces at odd angles, boxes to cut up etc. It will also look better painted to match the rest of the case, or the contrasting color already used case sections. Tiny bottles of latex in many shades carried in craft stores, Michael's etc.

One effect on behavior: when backing up tilted, Neato normally does not press the bumper edge onto the floor; it rests on the beveled part of the brush guard. The lowered edge will press the floor. So when Neato starts to move forward still tilted, the edge on the floor can depress the bumper. This creates an extra backward move, after which the bumper is off the floor again and Neato moves normally. This effect might be limited to running on carpet which will grab the lowered edge more.

Inquire re any further details needed when wanting to use one of these.

[glnc222]

wire and plastic combo version

wire reinforced plastic construction

installed pivoting extender, rough version

Rough version a bit oversize; could be 3/4" high and 1/8" thick with 1/16" wire.

Takes a while to make; needs a factory manufactured part. More shop tools and proper techniques might simplify -- more glue, less tape.

[edit] pivoted 3/4" forwards of the rear edge of the bumper.

Last practical mod I can think of for this brand (not just this addition) -- like that Tango in Paris. One of Neato's advantages it can be perfected in some ways while being low cost. Absence of any competitors in its price range doesn't put much pressure on them to make rapid improvements -- it's up to the users.