PrecisionHardware-in-the-LoopTestBench
Deterministic sub-10µs flight actuator simulation, FPGA DMA integration, and live telemetry capture for aerospace qualification.
The Brief
Aurora Defense manufactures electromechanical actuators and flight control computers for autonomous aerial vehicles. Flight certification requires Hardware-in-the-Loop (HIL) simulation test runs where simulated aerodynamic wind shear, hydraulic pressure drops, and electrical faults are injected into physical avionics hardware running at 10,000 Hz loop rates.
The clients existing software test harness suffered from non-deterministic operating system interrupts, introducing up to 250 microseconds of timing jitter. This jitter corrupted simulated control-surface feedback loops, leading to spurious false-positive actuator flutter flags and weeks of delayed aerospace certification audits.
Apache Spark was hired to engineer a microsecond-deterministic software harness and FPGA interface that captures, computes, and responds to avionics feedback without missing a single simulation cycle.
Engineering Approach
We developed a bare-metal execution harness running atop custom Linux kernels with RT-Preempt and isolated CPU core pinning. We engineered high-performance PCIe DMA drivers interfacing directly with custom Xilinx UltraScale+ FPGAs, enabling zero-copy circular memory ring buffers between hardware ADC/DAC channels and simulation models. A companion telemetry web application streams real-time Bode plots and Fourier phase analysis to test engineers via binary WebSockets with zero host performance impact.
Operational Outcome
Timing jitter reduced from 250µs to 4.1 microseconds across 1,200 continuous test hours. Aurora achieved FAA and defense hardware-in-the-loop qualification ahead of schedule, cutting physical wind-tunnel requirements by 64%.
Schematic Delivery Pipeline
Aerospace bus transceivers decode ARINC 429 and MIL-STD-1553 signals at physical layer.
PCIe bus transfers raw sensor packets directly into pinned host CPU cache lines.
Real-time Rust kernel executes aerodynamic physics matrix equations in sub-8µs.
Binary WebSocket telemetry feeds diagnostic dashboard for live waveform inspection.
Legacy vs Modernized Architecture
Technical Plates & Trace Graphs
Hardware-in-the-loop avionics test rack with flight computer under test.
Oscilloscope trace showing deterministic 10kHz loop timing and sub-5µs response.
Telemetry web console displaying real-time Fourier transform phase margin.
“Microsecond determinism is rare in modern software engineering. Apache Spark delivered code that operates with the mechanical precision of a Swiss watch. Our flight control systems are safer because of them.”