HD1970LAhead

PBPS Collapse and Looking Ahead: During the PBPS attrition process I was constantly searching for new business applications. I kept in contact with Lou Purpura, then on staff to Program Manager Bob Kaesby, with office along “mahogany row. Lou was part of noon time bridge bunch that included Tom Schuler, Bob Neise & Ray Curci. Lou and I had kept in close contact since working at adjacent desks in 1955 – it was now about 1970. During the Minuteman program Lou and Ray had arranged periodic meetings with Lockheed to exchange ideas on their Polaris & Trident Missile systems launched from submarines and our Minuteman launched from a silo. In conversations, Lou and I called a follow on to the MM III an MX – soon others within Autonetics and TRW were also using the term MX. Thus it seemed only natural when the AF referred to an MX missile in news releases associated with congressional funding actions. Lou gave me a call and said he’d set up a meeting with Lockheed and had invited TRW along for a discussion of future missile developments.

MM I had four hinged tilting nozzles one at the end of four stub pipes. Two were + – pitch, two were + – yaw and roll was achieved with + yaw & – yaw. This method consumed considerable envelope reducing the amount of propellant that could be carried.

MM II stage II used secondary injection into a single fixed nozzle partially buried up in the case. This packaged more propellant but required a heavy control system.

MM III stage II and III used secondary injection, stage I was still the original tilting nozzle system.

MX could use the new gimbaled nozzles for all three stages, an almost idealistic design. Once a gimbaled nozzle is aligned with the missile CG it required very little control power to stay aligned.

The problems with a single gimbaled nozzle is that you need a separate roll control mechanism.

Lockheed Gimbaled Nozzle Design: During such and exchange Lockheed gave us a tour and presentation of a Lockheed Gimbaled Nozzle design concept for large solid propellant boosters. Their engineer, I don’t recall his name, used laminating layers of metal, rubber, metal rubber, to make a ring which attached to the case and to the nozzle forward of the nozzle throat. When propellant was ignited case pressure was applied to the laminated rubber rings, causing these laminated rings to behave as if a fluid joint – permitting the nozzle to be gimbaled. I was immediately reminded of the use of a Hydropress to flow rubber about form blocks to bend parts to shape. This was a significant improvement over secondary injection control, and was soon adapted by all motor contractors for their new designs. I took special note of the fact that it was Lockheed, not motor contractors, who came up with this design. Lockheed and Autonetics, control system integrators, were aware of such an advantage. Motor contractors had no incentive to evolve such a device unless requested by a customer – feasibility studies were needed and Lockheed took the initiative.

During our MM I Lockheed had shown us their first Polaris system, which even they admitted was a kluge, which they improved to be more like our MM I systems. Lockheed was the first to use a secondary injection for later systems, as we did on MM II & MM III -- we benefited from their experience.

Tube vs Silo Launch: During our Lockheed visit we talked about their launch problems from a tube in their submarine vs our “flying” missiles out of a silo. They push their missiles out of the tubes using pressure, missiles are lowered into a Styrofoam lined tube, the Styrofoam served as the pressure seal as well as shock attenuator. To make this work they had used a “flat raceway” for their stage connecting cables. I took special notice of the fact they were forced to make a flat raceway where our method posed no such design constraint.

Small Rocket Engines for Roll Control: They also showed us the small rocket engines used for roll control. These were provided by Lockheed, not the motor contractors. For Minuteman, TRW Propulsion placed these under their control by directing contracts to the Motor contractors – who bought such from others.

Advanced Studies at Norton AB: TRW at Norton AB and Aerospace near by were making studies and presenting proposals to the AF for follow on missiles. I was among those who attended a early meeting with TRW Propulsion and TRW G&C at Norton on what they had in mind. They perceived a much larger missile with more warheads.

First concepts for an MX missile: We arranged for the loan of Ray Ajamien, an excellent design engineer, who put together the concept of a future post boost control section for what I was calling MX. We had moved from quarters in building 232 to lesser accommodations in bldg 73. Knowing a future missile would have a much larger PBPS and it seem appropriate to create a concepts of what that might be.

G&C inside the PBPS: I knew we would not have the luxury of a full section of the missile devoted to the Guidance system only, so I had Ray place a drawer in the side so the Guidance & Control system could be placed inside the Propulsion System cavity, as there would be plenty of room. At the time what was left of Bellamy’s organization had been placed under Dale McLoud of Inertial Navigation. Dales first reaction was No Way was their Guidance and Control system going to be inside the Propulsion System! However in the end that’s exactly how it was done. It was the only sensible option. A short time later Ray went to work for Space Division on the Space Shuttle.

Roll Control Requirements: Terry Miwa a long time friend from TRW, now in charge of their requirements analysis unit, came up with MX stage I roll requirements. Lou called me when he received the information -- we agreed the requirement was excessive. Terry had simply extrapolated from MM I tilting nozzle roll capability to define an MX need. Lou said that’s way in excess of what Lockeed uses. I said yeah but remember they have that flat raceway – we need to find a way of converting our 6” hump raceway to a flat one. I’ll try to do some realistic calculations on the present raceway roll disturbance and what we can do to make a flat raceway. Lou said great and when you do make contact with Art Zimmerman TRW Norton AB, a mutual friend of ours on what you come up with. I made a layout plus calculations on maximum roll torque caused by a 6” hump, missile length when exposed to 450 mile extreme wind at launch, a value I recalled that Dave Byles had used. I plotted this up, called Art who picked it up on his way to see Terry at TRW Redondo CA. I had also looked up what Lockheed told us they used for their Trident missile for roll and included it with the information given to Art. Terry completely reevaluated his roll requirement number to a more reasonable value. Zimmerman moved to Redondo not long after that and I lost track of another good friend. We needed to achieve a consensus of opinion that an MX should have a flat raceway.

Shuler’s List: A the time they had gathered an unusual collection of people in bldg 73 – most of the ex supervisors now out of jobs due to the upheaval of MM III winding down – I was one of them. It was some two years later, in a conversation with Lou, that I learned how that came about. Cutbacks had become chaos, like with 90 secretaries laid off in one day as the entire Minuteman program was effected. Someone discovered that Malcomb Johnson was on “open transfer” meaning he didn’t have a job and had about two weeks in which to find one or else out the door. When Shuler learned of this he said hold up, we cant lay off the very people we need for future business. Tom proceeded to personally make a list which he sent to personnel with the message that he was to be personally notified before any one of those people was laid off. With out knowing it, a few of us became the “untouchables”. Tom made good choices, they were all quality people who soon again proved their value on new assignments as we began to recover.

Control Cable Signal Bus for Flat Raceway: I began pouring my energy into the idea of not only making a flat raceway but also using a signal data buss in lieu of dedicated wires. I recalled how the rural telephone lines where I grew up. They were called “part lines” where each farmer on the line had “their” ring, to which they would answer. They also had an emergency ring where everyone answered, such as giving warning of a wheat fire – a HELP call to all. I decided it would be a neat thing to use a few small signal wires to replace the many. I designed a protocol for a missile “Party Line”. Some didn’t understand the meaning I intended, thinking it was a political party, so I dropped the term. I work out a concept for shifting a set of serial bits from up stage to all the down stages, to unload a “command” cargo of bits, then load and ship back a return cargo of “feedback” bits. The very recent TTL dual inline chip literature showed shift registers and latch registers I could use to do that. I knew it was a good concept.

This was many years before the RS-232 Serial protocol using UART (Universal Asynchronous Receiver Transmitter) chips. It was also before the creation of the Mil-Std-1553 for bursts of data packets – which became a standard for the Aircraft Industry.

Presentation of Serial Bus and Flat Cable concept to TRW: I refined my ideas into a presentation to G&C and Propulsion TRW people I knew. They were advisors to and our communications window to the AF. I could tell they were very impress. Don Kennedy of TRW Propulsion, one of their good guy out of Redondo office, turned to Bellamy and said, I believe you’ve just lost a good propulsion man to electronics.

Why do we do things the hard way?: Later at Norton AB for a meeting we were held up until an AF officer could arrive, he had been miss directed to Redondo on the coast and now on his way to Norton East of San Bernadino. During this time I got to visiting with an AF officer I’d never met before. He seemed bright and interested so I made the comment, “sometimes we do things the hard way.” He asked what do you mean. So I went to a near by black board and drew a picture, showing our raceway and side wind – saying we build airfoils on our AF missiles while the Navy is not – we have a large roll disturbance and need large roll control authority – the Navy does not. We should flatten our cable. Right away his eyes lit up, this was his language and this was an opportunity for him, he now had a clear and valuable cause. This was the reaction I was hoping for – to receive directions that the MX shall have a low profile cable.

AF Funds TRW Data Bus Study: My sales pitch to TRW/AF on the use of a data bus turned out to be very successful, TRW proposed and were funded by the AF, to study the application of a data bus for an MX. I found out about it quite by accident when I went with Carl Body to Norton on another subject and sat in on his meeting. TRW was giving a briefing on their study – when someone asked what they were using as “requirements” for such a system, TRW presented the document they were using. I was startled to find it was one of three a reports I’d written and given to Dr Ken O’Kief of TRW Redondo. This is why Carl Body, then in charge of our cable systems, wanted me to sit in on the meeting – he knew they were using my report for requirements.

Unique Funding to Autonetics: Lou Purpura once said to me, we are very lucky, we have AF funding for studies, TRW and Motor Contractors have to make special proposals – that’s why TRW was funded to do the data bus study and why motor contractors were funded to do new servo actuator studies.

Later working with Don O’Niel on the B-1B program, I found it was Don, while G&C Project Engineer, who had set up this unusual funding arrangement as part of sustaining engineering during negotiations with the AF. From the AF and taxpayers stand point it was money very well spent. It is an enormous loss to wither away a capable organization during program transitions.

AF Funds Motor Contractors for Servo Actuator Studies: It was obvious from the start that TRW Propulsion wanted the motor contractors to provide the nozzle control actuators for the motors. Companies like Moog jumped at the chance to sell full servo actuators and not just servo valves – however they were cut off at the pass when Propulsion TRW issued, via AF, a study contract to the motor contractors with the stipulation that it be for methods other than hydraulic because it was already known how to build those. Thus began the design of solid propellant powered servo actuators. The Vickers solid propellant driven hydraulic pump was not given a chance. We lost our charter for MX servo actuator studies – the kind of work I’d done before the PBPS was no longer being done at Autonetics.

Capable People let go: Vern Vorwick, who had been a supervisor for Rocketdyne drove each day across the LA basin from his home in Canoga Park. We often discussed what the next move should be – of what we could do to prepare for getting a new contract. Not too long after that Vern was let go, he was a very capable fellow and I did my best to keep him on – but realized I’d be doing well to find a niche for myself. We were still in bldg 232, not yet consolidated in bldg 73.

Nuclear Hardness Criteria – Digital is Better: I had come to the conclusion that with the increased hardness requirements it would be necessary to convert our analog servo control electronics in each downstage Nozzle Control Unit, to digital. During a visit with Lou Purpura I said you know Lou, one of the biggest limiting factors a new missile design faces is the ever increasing nuclear hardness requirements the feel are necessary. Lou agreed.

The “since when did that stop you” Challenge: I had said to Lou, in addition to making a flat raceway and a serial data cable, we should convert present analog downstage electronics to digital – the upstage electronics is already digital. Lou agreed. I started to walk out of his office when Lou said, “why don’t you do that?” I turned back and said, “Lou you know I’m a mechanical, I don’t know anything about electronics!” Lou smiled and said, “yeah but since when did that ever stop you?” It was as if to say what better do you have to do? It was a challenge. Lou knew, and I didn’t, of Shulers list and the AF funding worked out by O’Niel.

At the time I didn’t know that the Inertial Platform electronics was analog. – In fact many years later I was asked by Jim Mesera of inertial Nav. to take on the job of digitalizing the inertial platform electronics. By then I had sense enough to decline.

Electronics Self Education Continued: I had been striving to learn more about electronics ever since I went to work for NAA / Autonetics.

Navaho period: Ever since I became part of NAA/Autonetics I had rubbed elbows with the electronics world. Initially it had been of necessity while operating a Navaho Extreme temperature test lab where it was necessary ot instrument and operate systems remotely. From military service I was accustomed to many kinds of electrical systems, but the test lab world entered a new domain. Thanks to Bob Kelley, a ham operator and experienced electronics test engineer – I learned much not available in books. At that time I bought electronic kits from Knight and Heathkit, building my own signal generators, oscilloscopes, vacuum tube voltmeters etc plus a Heathkit sterio hi-fi that used vacuum tubes. However I learned most when I built my own sterio hi fi amplifier using all transistors and no transformers – all were early version transistors – before these kinds of kits were on the market. That sterio amplifier is now in the Oberlin KS Museum.

MM1 & MM2 period: During this phase I dabbled with electronics but focused mostly on making cabinets and setting up a music system including a “real” type tape recorder. This was before cassette tapes. It was also set up with high quality speakers and phono deck for playing then new LP (long play) “flex” records while retaining backward compatibility with the old 78 rpm “hard” records. I also experimented with making my own radio’s, from simple sets to full superhetrodyne systems using transistors but modeled after vacuum tube carrier frequency transformer signal coupling. I bought a set of “Miller” coils, (oscillator plus three IF coils) only I couldn‘t get it to work. I set it aside – not wanting to give up on it.

MM3 period: For the first two years there was no time for dabbling with electronics, then as an escape I got out the radio that didn’t work and decided to give it another try. This time I tediously took the coils out of their cans and did a continuity check on each coil against the wiring diagram on the can – that was it!!! The wiring and diagram did not match! Within a few evenings I had the thing rebuilt and it worked. I felt relieved as I didn’t want to let something like that defeat me. This again proved that tenacity is an essential ingredient when experimenting with something new.

New dual inline TTL chip sets: While reading trade magazines I discovered that semiconductor manufacturers were advertising new logic devices based on then new TTL (Transistor to Transistor Logic). I sent for suppliers catalogs to find out what this was about. Our MM III program had been based on new advanced integrated circuits and the government funded extensive reliability study contracts. This was a huge stimulus to the semiconductor industry – making it possible to make better and more reliable integrated circuits. What was learned on military contracts was put to use in commercial products. In time the commercial products were just as reliable as our special Minuteman Proven Parts, however we could only use those qualified for MM. The AF provided special funding to semiconductor suppliers to maintain production lines and personnel to make the “qualified” MM parts – in the event more would be needed.

Serial Data Bus Demonstrator – For Flat Cable: I decided to build a serial data path which could be use for each stage by giving each stage a code. I worked out a message format in which the first part was the code that identified the stage address. Following it was the Pitch & Yaw servo commands , and discrete roll control & ordnance commands. I allowed 8 bits for address, 16 bits each for Pitch, Yaw, Roll and 8 bits for discrete signals. I set up a clock which ran upstage and down stage functions. For the first cut I wanted to keep it simple. I built the system into an electronic rack with the upper part “up stage” and the bottom part “down stage”. I used four 4 bit parallel load, parallel unload shift registers in series to move data in 16 bit packets. With my clock-counter I could move data down stage and return data back. It require five small wire data bus wires: two data, one clock, one +5 volt and one signal ground. This was the easy part, but to make a credible data bus, and how to you command and control something?

Electronic Parts: I was constantly reading magazines and sending off for information. What follows cuts the chase and leaps from TTL to CMOS. The design began using TTL parts and migrated to CMOS. The first Serial Data Bus demonstrator used all TTL parts.

Upper left compares TTL and CMOS devices. Upper right shows how to make a NOR gate logic gate. Zoom view to display family of logic symbols on left. These were placed in chip sets of four as shown in center. Mid right shows D Flip Flop and JK Flip Flop with Truth Tables. Lower left shows a 4 bit shift register made from D Flip Flops. Lower right shows how to make a square wave clock generator.

Home Projects: I used my electronic work bench at home to making digital devices. One of the first devices was a transistor tester and a flip flop. Previous work with analog electronics was very helpful. I used formica circuit boards and applied signals with my signal generator and look at outputs on the Oscilliscope or VTVM (vacuum tube voltmeter). Almost every night at home I’d read and read and built parts, slowly becoming acquainted and comfortable with what I was doing.

Idea Submittal -- Electronic Commutation of a Motors Magnetic Poles: While writing this I came across a 1970 Idea submittal that I worked on in my home hobby shop. It was well known that a squirrel cage motor speed locks on to the frequency of the power signal. If a user had the means of changing that frequency they could cause the motor to generate maximum power at a frequency the user selects. Heavy Duty Transistors permitted commutating the motor pole pieces at any frequency determined by the operator. I had visited about this idea with fellows at lunch. Everyone knew such a thing would work, but there had never been the means to switch heavy duty power before the availability of power transistors. I decided to make a model in order to prove the switching electronics. I had submitted the idea and was building the power switch modules for my home set up when I happened to look at a recent Controls Magazine. There it was, the very thing I was trying to do – the magazine article presented the idea – indicating work was already underway in the industry. I dropped my effort and moved on. Years later I read where Union Pacific has been deriving greatly improved efficiencies due to their new Electric Engines which permit adjusting the motor pole frequency to the rate of motion – thus getting maximum power, at any speed, without loosing wheel to rail traction.

Learning Logic Symbols and Truth Tables: I spent hours studying and experimenting with transistors, diodes, flip flops and logic devices. IBM and other computer makers manufactures made logic devices with discrete parts on plug in circuit boards. Semi conductor manufactures were making rapid progress combining more and more devices on a single chip. I just happened to come off the propulsion program in need of a new job at the time these new goodies were becoming available. The technology was rapidly changing, I was memorizing terms and truth tables and sending for sample parts. The main devices were AND, OR and EXCLUSIVE-OR and the inverse of these the NAND, NOR and EXCLUSIVENOR; where N means Not AND. A Line above an identifying letter means NOT. Outputs were usually designated a Q rather than O to save confusion. A line above a Q Ō indicates the inverse of Q, or Not Q. IBM cards were using resistor or diode couple discrete transistors to make logic elements and chip makers were integrating these in new chip families.

TTL Takes the Digital World by Storm: The Transistor to Transistor Logic took off driving all other devices out of the market. These were packaged in dual inline 16, then 18 then 24 pin standard sizes. A designer could look these up in manuals and put systems together as if arranging dominos. Without fully being aware, I had entered on the ground floor with an application eagerly ready and waiting that could make use of the new devices. I just couldn’t learn fast enough – and didn’t have the funds to move out fast – so I steadily plugged away at it.

Upper left shows a CMOS inverter, upper center a CMOS transmission Gate which can block or pass analog signals (will flow either direction), upper right an analog 1 of 4 signal selector. Center is a square wave clock generator. Mid left is a 4 bit parallel preload, up/down counter. Lower left is a binary to discrete 1 of 16 selector, to it’s right the inner logic of a D flip flop, and bottom right a 7 segment display selector.

Use of TTL Chips to Control Servo Actuators: It was one thing to communicate with my “party line” signal system and it was quite another to control servos. I would need a digital equivalent of an analog “summing junction” a forward loop amplifier equivalent and a feedback equivalent. My first focus was on the summing junction.

Digital Up/Down Counter Summing Junction: On the way to work the odometer of my car began acting up, a bad tachometer cable, but It gave me an idea. Digital counters were like an odometer, they could count up and count down. I could start with a command, then count down with feedback and what was left would be the error command to issue to the control valve. I could shift a command down the cable, strobe it’s command content into a latch register, from which it could be loaded in parallel into a counter. I could set up an iterative cycle during which the feedback would count down the number and the error stored in a valve command register. A digital counter was the summing junction – I could control extend or retract with a sign bit stored separately – to cause the counter to count up or down. I found there was a new parallel load up/down counter that would be great for that.

Parallel Load, Unload Shift Register: I also needed a parallel load and parallel unload shift register to send signals down the cable and response signals back. I found there was such a device made from D Flip Flops.

Signal Latch Holding Register: I looked for and found a register they called a latch which would serve as an unloading/loading dock for shifted data.

Voltage Controlled Multivibrator: I needed a way of converting the feedback voltage to a binary number. More searching revealed a voltage controlled multi-vibrator. I found these came in pairs, two per chip – one for pitch and one for yaw.

Pitch Yaw Command Generator: I could also use a pair of VCMs to convert pitch/yaw motions of a joy stick to binary commands. I could generate these upstage and ship them downstage. I could simulate flight control commands via the joy stick by hand, but how was I going to convert a binary error signal in the summing junction counter to a valve command. I needed to ramp small signals to a full on command. If there was a way to convert the smaller binary bits to a % on time – then I could cycle the % on time, sustain it and let the valve coil integrate the pulse width to a sustained analog output.

Valve Command from Pulse Width Shift Register: I could store % on time as a pulse width in a shift register and let it cycle at relatively high frequency until the next upgrade iteration. I could cycle the pulse width at 6 mhz, the same frequency as used for the feedback excitation. I decided to use a 16 bit shift register as providing enough command resolution.

Converting Binary to Pulse Width: It took several days before I could come up with a way to convert a binary 15 bits to a stack of 1 to 16 bits. Later I found I could us a look up table set in a memory device – but originally there were no memory devices available and I didn’t have the means to program a read only device – which were just then showing up on the market. The Micro-Electronics Division was just then coming out with a 1024 bit silicon on sapphire ROM device.

A Simple Way to Make a Clock -- no radio oscillators or crystal clocks: I was at first thrown off by looking up how radio oscillators were made. I then looked into the use of crystals. I hit pay dirt when I found it was very simple to use a pair of logic devices connected with resistor/capacitor to generate a steady clean square wave. The technician helping me was soon able to select an appropriate R/C combination to generate just what we needed.

Counters and Decoders: I found there were counter chips which could be cascaded to as many as needed. I found there were 1 of 4, 1 of 8 and 1 of 16 decoders – the building blocks were there to do whatever I need to do – once I had a high speed clock I could down count, subdivide, enable/disable/strobe actions as required.

Analog to Digital Feedback Converter: How to handle the feedback signal was a real challenge from the beginning. First I had to provide 6 khz excitation, then demodulate the AC in to DC out, then convert the DC to binary, including the sign bit, and to scale the signal. I used the 6 khz to drive a four transistor set as a demodulator. Feedback signals are so low that you cannot rectify by use of diodes because diodes have a threshold voltage drop that blocks off critically needed signal. I managed that with discrete parts – driven full on devices do not have a threshold voltage drop. Demodulators used on the Navaho program required four peanut sized vacuum tubes, as full wave rectifiers, and consumed an entire 1”x3”x5” plug in module. During the Navaho it took some time to understand the need for a demodulator and how it worked, with new transistors it was no problem.

Later during the Minuteman program I had visited with Gary Collins who invented the position transducers we were using about the idea of making a DC transducer by placing a transistor demod in the units. I found he was already working on the idea and later came out with a DC transducer as a product line.

Patent Disclosure for Variable Frequency Position Feedback: During the search for a better method I experimented with the idea of replacing the position transducer with a variable inductor – tunable with a core – that could converted to frequency as a function of position just as a capacitor could change the output of the kind of clock generator I was using. I abandon the idea because there were no useable variable inductors on the market. Later at a staff meeting George Anderson, my boss who had just returned from a Group Leaders meeting said the company had not been submitting enough patents – and wondered if anyone had something they could submit. I had been daydreaming on my immediate problem, then became aware everyone was looking at me! As they were earning the money I was consuming with my experimentation, I felt obligated to do something. I said I’ve had a number of ideas …. Immediately Frank Lettang spoke saying you don’t have to prove they work by building a model – some of those ideas you’ve told me about should qualify for a patent submittal. Thus I reluctantly submitted the inductive transducer idea for patent. The AF decided to accept it, assigned an patent attorney to work it up and some 10 yrs later a patent was issued and I was awarded a check for $1000 for the effort – all of us had been required to sign an agreement that the government not us owned any patents. I had recalled a 1930’s model Buick radio I’d taken apart which used what looked like inductor tuning slugs rather than variable capacitors to select radio signals. Thus I assumed such a device could be made – since I couldn’t buy such a thing for what I was doing I had too much to do to spend any more time on it. As it was it required many hours to put together credible information to back the credibility of the idea – especially in follow up phone calls from the patent attorney in Washington.

Successive Approximation Register: I later solved this problem by use of a Successive Approximation Register device that recently came on the market. By this process the SAR outputs a half way guess binary number, which is applied to a set of binary scaled resistors which convert the binary to analog which is fed back for comparison with the unknown analog signal. The SAR keeps homing in until there is a match and the binary number accepted as valid. The advantage is that it is very fast, requiring 16 steps to achieve 16 bit accuracy.

I don’t recall for sure but I believe I used the Voltage Controlled Multivibrator chip for this early demonstrator.

Electronics Rack Missile: I needed a way to demonstrate the concept so I set up an electronics rack with Upstage at the top and downstage at the bottom. I got the loan of two PBPS electric servo actuators from Jim Anderson to operate as Pitch and Yaw servos. Two more were added to represent another stage. In my shop at home I made two aluminum frames on which we mounted punched circuit boards.

Up-Stage Simulator: I mounted two potentiometers to the top board where an aluminum tube handle moved one for pitch and one for yaw. This worked so well I made a second one to command the second pair of servos. Voltage Controlled Multivibrators converted the potentiometer positions to a frequency output which was directed in it’s turn to a counter. The binary output from the counter was strobed into a latch and from the latch in the output shift register. A clock and timing was set up to manage the data bus protocol sequence.

Down-Stage Simulator: The feedback was connected through VCMs to up/down count the command parallel loaded into the “summing junction” counter. The valve command was shift register cycled as a pulse width applied in accordance to the sign bit to extend or retract the servo.

Demonstrations: Emil Kohler had been assigned to help and we worked together trouble shooting the circuits. We used an oscilloscope to check the storing of signals in the devices. But we could not “see” the process at work other than watching the response of the servos to wiggling the joysticks at the top.

It was a thrilling feeling to be able to wiggle the joysticks and watch the servos follow with only a few tiny wires connecting top and bottom.

Our first visitor was Dale McLoud, who sent Walt Evans to look over what we had done. Evans had invented Root Locus method of servo loop analysis and later suffered a stroke -- he car pooled with George Keller during the Navaho program.

Our second visitor was Tom Shuler. Tom looked and listen dead pan. After explaining how it worked and what we were trying to prove I said, OK Tom stand here, wiggle the control sticks and watch the servo movement below. We were delighted to see Tom’s countenance change from dead pan to a big smile.

Concept Review Meeting: We had a concepts review meeting in bldg 73 attended by many of those working on concepts applicable to new business. This included Dale McLoud, Bob Niese, Mal Johnson, Dale Leisy, and others. When asked about how the system I had put together was to accommodate servo-loop shaping problems -- I made some irresponsible statements – which Mal Johnson never let me forget it. I’d said to McLoud we don’t need that old shaping stuff any more, digital doesn’t use that. Others thought I had said we didn’t need to perform shaping loop functions. I intended to say we didn’t need to use resistor capacitor operational amplifier shaping networks. In reality I had been so intent on determining how to do the serial data bus thing and to achieve digital control of servos, that I had totally ignored the shaping network problem. Our Minuteman servo actuators didn’t require shaping networks – however we soon became aware the new kinds of MX actuators anticipated by the Motor Contractors would.

New Office – New Room Mate, Mal Johnson: We were moved into bldg 231 and Mal Johnson and I into a ground floor office. We were now on staff to Group Leader George Anderson as a part of Navigation System. Georges Group made the components used in the inertial platform like the analog servo controls and test equipment – he had many high quality people working for him.

Hydraulic Servo nil filtering – Turbine Gas Servo much filtering

Digital P-92 Signal Processor Requirements: Up to the time of the data bus demonstration and concepts review meeting I had been assuming we would be using hydraulic servos, for which there were no significant signal conditioning requirements. Now we were hearing rumblings that the Motor Contractors – with TRW Propulsion support had released two contracts for the development of solid propellant gas driven servo actuators for gimbal nozzle control. Mal Johnson and others had been contacted with regard to doing attitude control using such devices. It became obvious that these would be far different than controlling hydraulic servos. I visited with Mal about this saying I needed something to use as design criteria for making a signal processor. From this it was agreed that if I placed digital filtering capability in the forward loop as well as the feedback loop that we should be able to accommodate whatever they come up with. Any prior filtering needed could be done by the upstage Flight Control Computer.

Who would be Responsible for Servo Actuator Electronics? We had meetings with TRW G&C about what would be needed for servo actuator control electronics. They were asking what would happen if the electronics was given to the Motor Contractors along with the servo actuators. This was discussed in some length. I kept saying the responsibility for control and stability should remain with Autonetics. That from past experience with roll control stage II etc we knew motor contractors did not have the expertise to do electronics. At this point we were locked on the idea of having a data bus with servo electronics down stage. They wanted Autonetics to be the ones responsible for testing the adequacy of any system – but who would design the electronics for the vehicle was left up in the air. The designers of the gas driven servo actuators for motor contractor tests were providing their own electronics.

Data Bus Abandon – Wire Direct: I made layout studies on the idea of doing away with a data bus and moving all electronics up stage. I found that this would fit well as a flat cable – that it was a doable concept. I went for another visit with Lou, saying I believe we should work on the proposition that we do all the downstage electronics functions up stage – that way we can be assured of keeping that part of the business, and perhaps we could find a way to time share the electronics from one stage to the next. That it only had to handle two stages at a time for a brief period during staging. Lou agreed – adding we can probably make it a part of the Flight Control Computer.

Even after I’d worked the details on how to do this, selling the idea encountered the momentum built up for a data bus. What had been sold had to be unsold.

Downstage vs Upstage Electronics

Digital Arithmetic and Shaping Networks: It had become obvious that the system concept I had would be required to do data processing – I began to call it a signal processor, or a digital P-92, replacement for our current upstage analog P-92 controls electronics box. This became a totally new challenge for me, I had to determine how to digital computations and needed a model of what such a signal processor should do.

Digital Computer Design Book: On a week end visit to south coast plaza I came upon a book on Digital Computer Design; I bought it and poured myself into learning how to do arithmetic computations. Thankfully the industry had come out with an Arithmetic Logic Unit chip, and later with a Look Ahead Carry chip. By use of this book I learned that you need to precondition binary numbers to be either in 1’s Compliment or 2’s Compliment before or after doing an arithmetic operation. I agonized over which way was best. I also studied architecture previously used and applied it to the new chips available to me that were not covered by the book. There were no “cookbook” designs to follow but I was able to extrapolate. One of the things I found useful was a Booths Algorithm, which was the logic used associated with multiplications on what is done next.

Multiplication by repeated addition: I soon found that the Arithmetic Logic Units could add or subtract but could not do multiply or divide. I also found that I could do division by shifting decimal point and multiplying. However our applications never had a need to divide, but our multiplication demands would become tremendous and a critical factor in the design.

LaPlace, Z Transforms, and Sample Data shaping methods

Sample Data Systems: I was having a terrible time reading many books, becoming bogged down trying to determine how to perform signal conditioning function with a digital processor. I was becoming as irritated with the books and I was with my own ineptness. The Blair Bona came to my rescue. Blair would often come in to visit with Mal and observed me struggling with my face in a text book. We’d become acquainted on such things as how to rig up switched to turn on/off garage door lights from house and garage. Blair said forget that stuff in those books this is what you need. He proceeded to my black board and wrote a lines worth of differential equations, which I could follow. He then expressed the same information in Laplace transforms used for analog systems, which I didn’t understand but could track to a degree. He also showed Z Transforms then converted those to Sample Data representation. I didn’t understand right away how it worked, but I could certainly understand the data processing method. It was as if someone had written translations on a Rosetta Stone – this immediately illuminated the way to do things. I said don’t erase anything until I can write that down. Thank goodness he happened to take an interest in that because it lifted me out of a pit, I had been lost. Using combinations of information I began the design of a Digital Signal Processor – a Digital P-92.

Digital Processing required for One Gas Turbine Servo Actuator

CMOS Transistors – Transmission Gates – Analog Switches: RCA had recently come out with a family of CMOS chips, they had been #1 with vacuum tubes and were on track with their venture into CMOS but they gave up too quick. RCA, GE and Motorola literature was excellent. Motorola often used a pair of CMOS devices as a “transmission gate”. From the literature I could see that a CMOS device was quite different than a TTL logic device. A TTL transistor had a Collector input, Emitter output and a Base control – but it was one way flow. Current through the base could cause current to flow from in at collector and out at emitter. The CMOS (Complimentary Metal Oxide Semiconductor) had an Source input, Drain output and Gate control. The term complimentary indicated that when a plus signal was applied to the Base it would open the Source and close the Drain – a minus signal would close the Source and open the drain – the Source and Drain were always the opposite, the compliment, of the other. An advantage of CMOS was that it was either ON or OFF, it did not leak power to stay on as a TTL required. However the Motorola term of calling it a Transmission Gate, indicated that signal current could flow either way. It was like lifting a gate, opening either way, not like a one way swinging gate that opened only one way.

Emil Koehler helped me understand how to operate a bipolar transistor with collector-base-emitter, you “sourced” it (supplied current) to turn it on or would “sink” it (drain current away) to turn it off. He also taught me that if you turn a transistor full on, it has little voltage drop and does not heat, if you turn it off there is no current flow, thus no heat. Amplifiers operating in an analog mode are causing the transistor to throttle current flow, causing a voltage drop across the transistor causing it to heat.

“H” Valve Driver Switch: Emil also showed me what he called an H switch to reverse flow through a coil. Think of it as having a transistor in each of the four legs, that the cross bar is a coil, that current enters at the top and goes out the bottom of the H. By switching on upper left and lower right flow goes from left to right in the coil. Do the reverse thus and current flow is reversed.

Digital Servo Valve: RCA 4016 had four independent CMOS transistors. I connected them as an H switch to an 8ma servo valve coil and cause them to alternately flip flop valve current flow. It just operated cool and neat as can be for any kind of duty cycle I used. Fantastic! This caused an Analog Servo valve to behave as a Digital Servo Valve!

“H” switch lower right. 1 & 4 or 2 & 3 CMOS transistors enabled by sign bit to extend or retract command.

Status Detection added to verify valid valve driver for Silo Test

% On Time Modulation (used) vs Bang Bang Modulation

Feedback select, demodulate, Analog to Digital convert, 16 bit value ship – pre SAR method

Block Diagram of Processing for One Servo Actuator

Control Cycle Timing Protocol

Booster Control Functions

Servo Processing Timing Diagram

Data Bus Timing – Later Abandon

Princeton Algorithm Mechanization

Princeton Algorithm Multi Coefficient Processing

Speed Requirement – Close each servo loop every 2 milliseconds: I frequently checked with Mal Johnson on how fast the data had to be processed. As the design concept had operate in a nuclear event environment, I assumed a down grade of 50% in speed as compared to commercial bi-polar parts. Once I had a mechanization that worked I did speed calculations and found I couldn’t handle all seven multiplies on four servos, counting worse case staging overlap, in the allocated 2 milliseconds. I was simply not able to do all the defined functions fast enough. Again Dr Blair Bona came to my rescue.

Princeton Algorithm: Blair said what you need to do is use the Princeton Algorithm. This permits setting up coefficients in such a way that a multiplication can be done much faster. That was in 1975 and now 2002 I don’t recall exactly how that worked but it took advantage of how shifting a binary number does an instant multiply by shifting the binary “decimal point”. Anyway I modified the design to handle arithmetic in this way – now the computations could be done fast enough. I presented these findings to Dr O’Kief of TRW, he wrote a report on it and this put the subject to bed about digital being fast enough for the high speed servo loops.

Compute fast -- the Missile wants to Fly Backwards: The center of pressure is forward of the cg on a missile during stage I boost. The applied torque if miss aligned wants to flip the missile. Thus the attitude error must be kept within a limit cycle of 1 degree – this requires very fast corrective action by the servos.

Programmable Executive Program

Dr Ken O’Kief’s Appraisal: We were at TRW Redondo and had been going over the concepts for what I had always called a digital signal processor, or a digital P-92 the name of our analog processor. One day he leaned back and said, “this is fantastic – but it’s not a processor, it’s a programmable computer, it has all the attributes of a full up computer.” Since I didn’t know about computers, I’d never thought of it that way, I was only making use of the new TTL and CMOS devices to do signal processing; going another step each time to solve a problem. We knew we’d need shaping networks to handle new servos so I’d incorporated the ability to reprogram coefficients, for each stage, then change when stages changed. I’d bought a book on digital design at a book store to find out how to do arithmetic, learning of 1’s and 2’s complements and such things as booths algorithm for look ahead carry. Arithmetic logic units had just come out, I sent for sample parts and made use of them.

Shortly after that I learn that O’Kief had a Phd in computer science – he said you were so far ahead, using these new TTL parts, from what we were doing in school -- I didn’t want to tell you!! His comments came as a surprise to me as I constantly had a feeling of being behind trying to catch up, always feeling dumb, each day faced with something I didn’t know how to do. Thanks to Blair Bona, who told me about the Princeton Algorithm, I was able to get the “signal processor” to work fast enough.

When going out to lunch O’Kief would tell me about Mexican history and I’d tell him what I was learning about biology. He once called me up, asking if I’d join him in writing a book on the DNA molecule, saying we could do better than an existing book by Asimoff. I declined as I was reading a book by Watson, one of the co-discoverers of DNA, on Molecular Biology and was overwhelmed his good book on the subject. Thus in the recent year 2002 meeting with Bob Cummings I knew that ecoli cells were the most studied and ideal for making math models of their inner workings.

Thanks To Elliott Buxton, Hydraulic Servos Win Out for the MX:

See Through Clock: Aunt Margaret and Uncle Francis Barclay had given us a very nice looking clock with see through glass face with minute hand, caused to rotate by a motor at the base, with follower hour hand located at the center, indexed to it’s dangling weight. The clock would stop because the glass was a friction fit, the slightest dust would bring the small motor in the base to a halt. Such a design with small rollers to support the glass would have provided sustained operation.

Later I thought of levitating a disk in the horizontal plane and using stepping magnets, as described below, to rotate the disk. The face would be displayed to a viewer as if vertical by use of mirror.

Mechanical Amplificaton with Light: The Oxygen Analyzers we used in the Bomb Shelter test facility to measure oxygen content in ovens, used a small mirror, rotated by an internal sensing mechanism, to project a band of light on the face of the instrument. I marveled at how clever, this amplified the tiny movement of the mechanism to an 8 “ swing a person could see from across a room.

Wall Clock: I sometimes projected mental images of a clocks face on a wall or ceiling by projecting light through a glass clock face. I was always fascinated by things which caused the viewer to ask now how did they do that? Today with so many kinds of computer generated clocks and displays – such mechanical things seem antique.

Gear With Three Teeth: It occurred to me that if you had a large diameter gear and you wanted to step its rotation you only needed three gear teeth: one to lock it in place, one to push clockwise and one to push counter clockwise. Clocks have an escape mechanism which permits a power source to move a gear one tooth at a time. Early mechanical jacks had a mechanism that permitted lifting a car one tooth at a time, or lowering one tooth at a time. I’d been thinking was in terms of digital bits, it seemed that all that was needed to make a bit stepping device was three steps: hold, push, pull.

This seemed to be applicable to many forms: fluid, mechanical & electromagnetic.

Liquid version: I drew the concept of a hydraulic device with a square threaded center shaft in a cylinder, where there were three ports: one over a land, and one over the left or right side. Fluid ported to one side would cause the land to move and cover the hole, having moved one step. If ported to the other side, it would move one step in the opposite direction. I don’t at present recall the details of the design, but constructed on paper a hydraulic actuator which would step forward or backward by walking a three port control with the land blocking the commanding port when a step was achieved. I had in mind making a digital actuator. Though I was convinced it would work, I dropped the idea when I realized the positioning resolution I required fine passages which would clog with contaminates. I believe the design of this has since been lost.

Mechanical version: I made a design sketches of three solenoid plungers each representing a gear tooth. These could walk a spur gear by walking the solenoid command sequence. This was abandon

Magnetic version: I made a paper design of a clock face with magnetic pole pieces at 1 minute increments. These were to be magnetically pulled then locked in place by walking or locking the commutation of three electromagnets. I actually built a 1/8 inch masonite disc with nail segments place about the outer edge with the idea that electromagnets, commanded by transistor switches could step rotation of the disk. I never completed the device as I didn’t have the means at hand to make and wind coils on the pulling/locking pole pieces. Also I had not yet mastered how to make a transistor driver and clocked control of their commutation. I believe the design of this has been lost.

About a year later I read an article showing where someone had made a clock that worked on this principle. I told the kids of the article – they had watched the construction of the disk with nail stubs in it – wondering what’s that?