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On-chip Learning Neural Network Hardware Implementation for Real-time Control. Prof. Dr. Martin Brooke Bortecene Terlemez. Current Status. Simulation Two frequency simulation Added noise simulation Experiments 1 second suppression Long runs. u. Unstable. x. Combustion Model.
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On-chip Learning Neural Network Hardware Implementation for Real-time Control Prof. Dr. Martin Brooke Bortecene Terlemez
Current Status • Simulation • Two frequency simulation • Added noise simulation • Experiments • 1 second suppression • Long runs
u Unstable x Combustion Model Delay 1.5 ms error error Delay line Software Simulation of Neural Network Chip Simulation Setup
One Frequency Result f = 400Hz b =
Two Frequency Results f = 400Hz 700Hz b =
Uncontrolled Engine Neural Network Controlled Engine 10 % Added Noise Results f=400Hz z=0.005 b=1
Short run-time f = 400 Hz
Long run-time f = 400 Hz
Experimental Conclusions • Suppression of Oscillation in less than few seconds. • Continuous Adaptation.
Issues • Competing technology status • General Purpose HWvsDedicated HW • Controller Initialization • How to find optimum weights? • How to set the weights?
Dedicated NN Hardware • Serial Digital [1] • Partially Parallel Digital [2] • Fully Parallel Digital [3] • Fully Parallel Analog [4]
References • [1] Torsten Lehmann, Erik Bruun, and Casper Dietrich, “Mixed Analog/Digital Matrix-Vector Multiplier for Neural Network Synapses.” Analog Integrated Circuits and Signal Processing, 9, pp. 55-63, 1996. • [2] Antonio J. Montalvo, Ronald S. Gyurcsik, and John J. Paulos, “An Analog VLSI Neural Network with On-Chip Perturbation Learning”, IEEE Journal of Solid-State Circuits, Vol. 32, No. 4, April 1997. • [3] S. Neusser and B. Hofflinger, "Parallel Digital Neural Hardware for Controller Design", Mathematics and Computers in Simulation, Vol. 41, Pp. 149-160, 1996. • [4] Maurizio Valle, Daniele D. Caviglia, and Ciacomo M. Bisio, “An Experimental Analog VLSI Neural Network with On-Chip Back-Propagation Learning”, Analog Integrated Circuits and Signal Processing, 9, pp. 231-245, 1996.
Time for One Forward Propagation (Time: Number of Gate Delays)
Area (Area: Number of Transistors)
Today’s Technology - 0.35 mm CMOS Speed (ns) Chip Area (mm2)
Area and Time Estimation for 70-nm CMOS Process Speed (ns) Chip Area (mm2)
Controller Initialization • How to find weights • Simulation • Is this good enough? • Recorded training
Simulation • Problem : Current chips are volatile • Solution : FPGA
Recorded Simulation (current chip) • Error Decrease Signal • Random Sequence Error Decreases f = 400Hz z = 0.0 b = 0.1
Controller Initialization • How to set weights • Recorded simulation/training (current chips) • permanent analog weight • Digital weight storage (FPGA, custom)
log Digital Non-volitile Memories (?) ISD- Voic e Re co rd er Br oo ke , FG De vi ce s Ya ng Kah ng et.al and Circuits Ada pt iv e and S ze Ret ina AF G A ET A N N STL S Shib ata/ Ohm i ...... . 1967 1989 1999 Permanent Weight Storage EEPROM - FLASH
Past EEPROM NN • Permanent weight version of current chip
(n-well) Permanent Analog Weight: Floating-Gate MOS Regular CMOS Floating Gate MOS
Digital Weight Storage • Custom digital chips • Field Programmable Gate Arrays (FPGA)
Custom digital chips • 13 bit programmable DAC • 6-8 bits probably enough • Expensive/slow to develop
Field Programmable Gate Arrays (FPGA) • Reconfigurable • Flexible • Low-cost design cycle • 1992: First ANN on FPGA • 30 of XC3090 (8000 gates each) used • Each neuron with 14 synapses:2 FPGA + 1 EPROM • Today: very high density FPGAs with partial dynamic reconfiguration made possible ( >3 million gates)
RRANN • Run-time Reconfigurable Artificial Neural Networks (RRANN) • Time sharing the limited computing resource.
Conclusion • FPGA technology ready • Faster development • Plan to adapt current test setups • Plan to attempt weight initialization • Recorded simulation/ training (current chips) • Digital weights (FPGA)