------------------------------------------------------- 11-Jan-80 1450 FORWARD at USC-ECL Roche World Date: 11 JAN 1980 1425-PST From: FORWARD at USC-ECL Subject: Roche World To: hpm at SAIL, ZIM at MIT-MC cc: Forward Since you were so much help on my last novel, I would like to ask for some help on my next one. I am mailing to you both a copy of the bare story outline, some description of the characters (including the alien characters), and the technical appendix, which in this book will be in the form of congressional hearings in 2076. Only the hearings will appear in the final manuscript. What I am looking for now are glaring errors (like when Mark found out that my neutron star cheela didn't have enough "light" to see with.), also any suggestions for other neat things to put in for incidental technology. Hans, I have a semi-intelligent computer on board the spacecraft and other vehicles. I now realize that I should give it some mobile unit capability so it can carry out repairs without involving the humans. I envision a small spider for routine inside tasks, a larger one for laser sail maintenance, and perhaps a larger tug for heavy work. Any other shapes sound better? "Dragon's Egg" will be coming out in May and you both will be getting copies autographed with profuse thanks. The book is doing well. Has nice quotes on the jacket from Asimov, Clarke, Drake, Dyson, Sheffield, Herbert, etc. English rights went for $10,000, German for $4,000, and Ballantine is dickering with the French and Japanese. Hardcover will stay on sale for about 9 months, then it goes into paperback next year. Thanks, Bob ------------------------------------------------------- 12-Jan-80 1301 FORWARD at USC-ECL Date: 12 JAN 1980 1302-PST From: FORWARD at USC-ECL To: hpm at SAIL What is your mailing address? ------------------------------------------------------- Progress Dear Uncle Bob, Hi. Looking forward (um...) to both your books. Won't let me FTP it this time, huh? Good thinking. I note you (and your offspring) haven't been slacking on short pieces either. My research is finished, the prints of live action parts of the cart movie are back, and one run came out very well; it will be edited with animated sequences into a 20 minute or so exposition, but it won't be finished until considerably after my degree. The thesis comitte will have to be satisfied with work prints. My thesis is somewhere between 40% and 80% done, depending how you measure. I intend to have a first draft done by the end of January, then go to Carnegie for a month but keep writing, then come back to Stanford at end of February and do orals during March. The address after our compaction is even shorter: Computer Science Dept. Stanford University Stanford, Ca. 94305 A favorite (though not yet practical) fantasy for a repair robot derives from the following observation: Once upon a time animals were shaped like sticks (worms), and couldn't manipulate or even locomote very well. Then the sticks grew smaller sticks and locomotion was much improved, and manipulation a little. Then the smaller sticks grew yet smaller sticks, and hands were invented, and manipulation got better. I visualize a robot that looks sort of like a tree, with a big stem, repeatedly branching into thinner, shorter and more numerous twigs, finally ending up in jillions of near-microscopic cilia. Each intermediate branch would have four to six degrees of freedom, and force sensing. It would need a huge amount of processing power to coordinate, but imagine it reaching into a piece of delicate mechanics, and rearranging parts by feel for a near instantaneous repair. You could make smaller robots by detaching subtrees. It could also walk with its appendages, even on ceilings with the tiny cilia holding onto cracks. If ths is too advanced, prune off the smaller branches. ------------------------------------------------------- 12-Jan-80 1657 FORWARD at USC-ECL Branching Robot Date: 12 JAN 1980 1657-PST From: FORWARD at USC-ECL Subject: Branching Robot To: hpm at SAIL cc: forward Excellent concept. May I steal it for my book? I will leave all the cilia on, and I especially like the idea of detaching portions. You should write a short science speculation piece on it and get it published so people don't think I invented it. (All of this AFTER you have finished your thesis.) Any ideas for a good name. "Bushy Bee" isn't quite it. Thanks, Bob Branching Ben, uh, Manipulating Mary, um, Forking Freddy, well, I'll thinks about it ------------------------------------------------------- Sure, I'd be tickled pink if you used it. If you knew the number of things I've put off till after my thesis ... ------------------------------------------------------- [MESSAGE FROM FORWRD at MIT-MC 12:48am] Its name is "Cristmas Bush". It has lots of varicolored lights that James (the computer) uses for inspection and communication and it keeps the humans aware of the computers presence. Of course, mostly we only see some small "spider" sub-bushes crawlign along the walls and ceilings to take care of some circuit problem in the walls, but at the beginning we see the whole "tree". It is not a tree, however, it is a "bush", sticks grow equally at both ends in a zero gee envvironment. (Your "Christmas Bush" just may tak over the whole story. But not really, considering it is just a tool of James/Jack/Jill. Great Uncle Bob How do you edit MC messages? ------------------------------------------------------- [I've edited messages in EMACS, then sent them, but I don't know of a mechanism for editing a message currently being SEND ed. The bush sounds festive indeed. Maybe it can talk and play merry tunes by vibrating its cilia (sort of like crickets). But where do the presents go?] ------------------------------------------------------- [MESSAGE FROM FORWRD at MIT-MC 1:03am] Just a way to defuse the "Big Brother is WATCHING you syndrome." More I think about it, the better I like it. Thanks. Did you get my mailing yet?? ------------------------------------------------------- [It certainly has a different flavor than HAL. Mail hasn't arrived yet, but it usually takes several days to pass through the necessary levels of sorting. One property of the bush you might consider is its ability to change size by about a factor of two. To give each branch the axial degree of freedom, I imagine a 2:1 telescoping motion. If all the branches do it, you get a fast and surprising movement] ------------------------------------------------------- Jan 15 Unconnected thoughts all strung together as if they were a paragraph The manuscript arrived today; much merriment so far. Is Keith Henson the originator of the space fortress inevitibility argument, or is there an older reference? I'll respect your copying caveats, of course. The lights in the robot could be part of an interferometry measurement system for accurate positioning of the subparts in the presence of deformation. With constant power/mass ratio, the small branches have a much higher movement frequency than the big ones. ------------------------------------------------------- 15-Jan-80 2005 FORWARD at USC-ECL Date: 15 JAN 1980 2005-PST From: FORWARD at USC-ECL To: hpm at SAIL Yes. Henson is the source, but I wonder if it is original with him. I think so, but will have to ask him. Perhaps Artibishiov (whoever) thought of that first too. Met Jerome Pearson at AIAA meeting today. Gave his paper on rotary rockets. He asked me out of the blue (we were talking about crazy people at the time if I remember) if I knew Hans Moravec. (I denied it.) The cilia frequency is probably high enough for talking with the humans? ------------------------------------------------------- [I've been meaning to write Pearson to ask for his last year's paper, as he seems to be generating them annually. Never heard of rotary rockets, except on 4'th of July. I would think well designed cilia could act as a phased array sound transmitter and receiver. Besides talking, they could maybe do ultrasonic inspections of the interior of repairees (but controlling computer is getting hairy). In 2076, congress dims the lights so they can see slides? Very conservative, aren't they? And a clerk to transcribe?] ------------------------------------------------------- 15-Jan-80 2128 FORWARD at USC-ECL Congress getting around to it. Date: 15 JAN 1980 2129-PST From: FORWARD at USC-ECL Subject: Congress getting around to it. To: hpm at SAIL cc: forward You caught me in a boo-boo. I will probably change it, but although they may have bright-light displays, I bet they still have a human recorder (although you may notice that they hardly use her/he). Actually, since I have a semi-intelligent robot spacecraft in 2026, they should have robot recorders in 2076. Thanks, little things like that can really destroy the "suspension of disbelief". ------------------------------------------------------- 14-Apr-80 2232 FORWARD at USC-ECL Christmas Bush Date: 14 APR 1980 2223-PST From: FORWARD at USC-ECL Subject: Christmas Bush To: hpm at SAIL cc: DGSHAP at MIT-AI, forward I recently sat down and documented the ideas for the mobile "repair" robot that you suggested for the "hands" for the computers that I use in Roche World. This is a section out of the "hearings" appendix that is the science fact background for the novel. Still a first draft, so needs work. I expect that the "shoulder" imps will become an important part of each of the human characters behavior. (Why pause to scratch your ear when you have someone that can do it for you?) THE CHRISTMAS BUSH The hands and eyes of the near-human computers that ran the various vehicles on the expedition were embodied in a mobile extension of the computer, popularly called the "Christmas Bush" because of the twinkling lights on the bushy multi-branched structure. The development of the bushlike shape for the repair and maintenance robot has a parallel in the development of life forms on earth. Once upon a time, the most complex animal was a worm. The stick-like shape was poorly adapted for manipulation and even locomotion. Then these stick-like animals grew smaller sticks, called legs, and locomotion was much improved, although they were still poor at manipulating. Then the smaller sticks grew yet smaller sticks, and hands, with manipulating fingers were invented and precise manipulation of the environment became possible. The Christmas Bush is a manifold extension of this concept. The motile has a main trunk that repeatedly branches into thinner, shorter, and more numerous twigs, finally ending up with millions of near-microscopic cilia. Each intermediate branch has four to six degrees of freedom, and the force-sensing needed to handle large rugged objects, like door handles and pieces of equipment, as well as the delicate insides of a precision instrument. Each segment has some small amount of intelligence, but is mostly motor and communication system. The segments communicate with each other through their interconnections to coordinate their activities, but the main computer in the vehicle is the primary controller, communicating with the various portions of the bush through coded laser beams. It is the colored lasers sparkling from the various branches of the bush that give it the appearance of a Christmas tree. It takes a great deal of computational power to operate the many limbs of the bush, but the built-in "reflex" intelligence in the various levels of segmentation lessen the load on the main computer somewhat. The analogy of the isolated brain with its massive intelligence communicating with the finger muscles on the hand out at the end of the arm through nerve impulses is a good one, where the laser beams act the role of the nerve impulses. The Christmas Bush, however, has capabilities that go way beyond that of the human hand. The bush can stick a "hand" inside a delicate piece of equipment, and using its lasers and detectors as light source and "eyes" rearrange the parts inside by feel and "sight" for a near instantaneous repair. The bush also has the ability to detach portions of itself to make smaller motiles. These could walk around on their larger appendages, and even walk up the walls and along the ceilings with the tiny cilia holding onto microscopic cracks in the surface. The smaller twigs on the bush are capable of very rapid motion. In free fall, these rapidly beating twigs allow the bush to propel itself through the air. Even at earth gravity, the smaller sub-trees can fly using their cilia. The speed of motion of the cilia is high enough that the tree can generate sound and can talk directly with the humans. Another interesting property of the bush is its ability to change size. Just as a human can go from a crouch to an erect position with the hands and fingers raised and change its height from less than one meter to almost three meters, the bush can shrink or stretch by almost a factor of five, from a short, squat bush to a tall, slender tree. Each human has a small sub-tree that stays with the human to act as the communication link to the main computer. Most of the crew have the tiny bushlet ride on their shoulder, although some of the women prefer to keep them in their hairdo. In addition to acting as the communication link to the computer, the imps also act as health monitors and personal servants. Their assistance is especially helpful in keeping the crewmembers hair in place when in a spacesuit, and are the ideal solution to the perennial problem of spacesuits, scratching an itchy nose. Yes, the imps go into the spacesuit with the humans, and more than one human life was saved on the mission by an imp detecting and repairing a suit failure or patching a leak. In fact, there are two computer motiles with each suited human. The personal one that stays with the human inside the suit, and the suit motile, usually larger in size, that stays with the suit. It is usually outside in the life-support backpack, but can worm its way inside through the air supply hose. We think that life would be weird with a semi-living creature always attached to us, yet think how bereft you feel when you have forgotten your eyeglasses, or pen, or wristwatch, or computer. I am tempted to make the computer and its appendages the "viewer" of the story. But since it cannot be too intelligent (in that case, why take humans along?), it might be a little hard for the average reader to "identify" with. Bob ------------------------------------------------------- Bushes Dear Uncle Bob, Your bush robot presentation looks great to me. I hadn't considered flight, but it seems obvious now that you mention it. In case you want to quantify the speed of the appendages as a function of their size, I calculate that the maximum frequency of a motion varies exactly inversely with the linear dimension of the segment. The assumptions going into the arithmetic are: The actuators are hydraulic cylinders (I assume other kinds of muscles would be affected by the same conservation laws) The segments are all exact scalings of each other. This means the pressure walls of the hydraulics grow thinner as the segments get smaller, cancelling the effect of higher curvature. Thus the maximum pressure is independent of size. The mass to be moved by a piston is proportional to the cube of linear dimension. The force exerted by a piston is proportional to the square of dimension. The stroke of the piston is proportion to the first power of dimension. --- Mix, and a few square roots combine to say cycle time is linearly proportional to dimension. Some of my "practical detail" fantasies may be slightly different from yours. I imagined power and data flowing from level to level. The data moves serially on coax, perhaps. Thicker coax can handle higher frequencies, thus the lower levels of the tree can handle the data concentration. Same for power. If the robot is mobile it needs internal power sources. Each segment can have a battery, but it may be too little to provide all the power that segment needs. If so, it makes sense to tap power from the much bigger batteries one or two levels down towards the stem of the bush. The battery two levels down is 64 times as massive, providing 64/4=16 times as much energy for the 4 segments at the upper levels. If you use this strategy, the first level or two can't power themselves. They can provide a stable framework if they passively lock their joints. The number of degrees of freedom necessary in each segment isn't clear to me. It would be nice if three would be adequate; an azimuth/elevation joint where the segment connects with its bigger root, and an axial rotation where it connects to smaller segments. Possibly a fourth degree, a telescoping of the segment length, is helpful. Six is almost certainly more than necessary. I intend to do theoretical studies of the control problems of such a machine at CMU, and possibly even build a simple three or four level working model. Current idea is for a recursive problem solver which passes plausible incomplete plans, with constraints, to right and left subtrees (things like, Left tree: stay on left side of plane A, and apply net force vector V to object. Right tree: stay on right side of plane A and apply force -V to object). If subtree problems can't be solved, complaint is passed back to originationg node, which tries something else. The theoretical work will be a lot of fun because the robot can be simulated on the 3D modelling machine (whose specifications have been expanded to permit collision detection of the modelled objects, as well as shaded graphics) I told you about once, which is another thing I've already started to do at CMU. Imagine a movie of a realistic looking 15 level bush picking up and moving objects, walking, or doing hula dances. Anyway, back to decorating the thesis. I'll be very glad to have that out of the way. ------------------------------------------------------- Date: 29 NOV 1980 1117-PST From: FORWARD at USC-ECL Subject: Christmas Bush To: moravec at CMU-10A Via: USC-ECL; 29 Nov 1980 1418-EST I am now to the section where I am describing the Christmas Bush. I had planned it to be a concatenation of triads, any sub-section of which was a smaller version of the original. But in attempting to draw it, I found it difficult to maintain the stuctural identity while still finding a decent way to attach each subsection to the larger portion. I am working on it here myself today, and will probably come up with a quad or hex-furcation scheme, but would appreciate any ideas you may have. ------------------------------------------------------- From: FORWARD at USC-ECL Subject: Christmas Bush To: moravec at CMU-10A cc: RLFORWARD Via: USC-ECL; 30 Nov 1980 2330-EST Unless you have a better idea I have decided on the following basic form. Six sticks radiating outward from a central point. Each stick has three equal segments connected by a joint in addition to the central joint. Like a six fingered hand or a daddy-long-legs spider. At the end of each "limb" is the connecting point for another six-sticked copy, one-half the size. At the end of those "branches" is another six-sticked half-sized copy, etc. The largest limbs are 1024 mm long, and they go down size 18 octaves to 1/64 mm (15 microns). Each stick is one-third the diameter of the next larger, so that the six sticks lying parallel are the same diameter as the rpeceeding stick. At full extension it can reach 4 meters. Normally the bush "walks" on three legs with flat 6-pointed played "feet". It uses two limbs as arms, and one as "head". This latter is usually complely flowered open into a bushy "head" which sees and talks. Any "hand" or further subsecion is also a six-limbed version. The joints give each subsection the clutching and opposed thumb capabilities of a hand. Since each subsection is a half-scale replica of the larger, it seems like it might be easy (?) to generate a computer drawing. Anyway. It satisfies me, and I am going with it. (Unless you find something much better). ------------------------------------------------------- Date: 1 December 1980 0014-EST (Monday) From: Hans Moravec at CMU-10A (R110HM60) To: FORWARD at USC-ECL Subject: Re: Christmas Bush CC: Hans Moravec at CMU-10A In-Reply-To: FORWARD@USC-ECL's message of 30 Nov 80 23:30-EST Origin: R110HM60 at CMU-10A; 1 Dec 1980 0014-EST Sounds just fine to me, except for one scaling problem. You say each successive order is half the length of the previous, but one third the diameter. You didn't specify starting diameter, but you have so many levels that the final ones must be skinny indeed. You need the 3 factor to pack six brances of one order onto one of the next if they have circular cross section. If you want the little bushlets to be scalings of the bigger ones, the length factor should also be 3 instead of two. Then you would probably do with less "octaves" Eleven levels of factor three is about same as 18 of two. An alternative is a slighlty more radical redisign. A scale factor of two is an area factor of four. You can get this, and constant cross section when folded, is the bush becomes half-scale in all dimensions at each branching, and has limbs of square cross-section. Four square branches thickness r can fold together with perfect packing into a square bundle of thickness 2r. The robot could walk on three of its four main branches, and use the fourth as a body. Three of the second order branches on the body become three arm/hands and the fourth becomes the main head. Otherwise it works very much as your hexapod. ------------------------------------------------------- Date: 1 DEC 1980 0817-PST From: FORWARD at USC-ECL Subject: Hexabush To: moravec at CMU-10A Via: USC-ECL; 1 Dec 1980 1116-EST You are right about 1/3 scaling. Design is now six arms coming from a hexagonal "shoulder" joint, in two sections with a ball "elbow" joint, and attaching to a hexagonal "wrist" joint that starts the next hex down. The "hand" is 1/3 the size of the previous hex. Will have to try drawing it to scale to see if there are any other bugs. ------------------------------------------------------- Date: 1 December 1980 2146-EST (Monday) From: Hans Moravec at CMU-10A (R110HM60) To: FORWARD at USC-ECL Subject: Re: Hexabush In-Reply-To: FORWARD@USC-ECL's message of 1 Dec 80 11:17-EST Your latest configuration has the nice property of non self-intersection not only when you fold the umbrella at all levels, but also when it flowers at any angle; so long as the angle is the same (or smaller) at the high levels as at the low. For instance when maximally extended, so that all the branches lie in nearly the same plane, the bounding circles of the spread hands just touch if the six arms are at equal 60 degree angles from each other.