ZIAA ARCHIVE RECORDANOMALY POST-MORTEMS
INC-2023-06failureVERIFIED RECORD
HAPTIC-RUNAWAY: Motorized Fader Haptic Feedback Oscillation Runaway
INC-2023-06HAZARD: MECHANICAL_CONTROL_RUNAWAYSTATUS: FIRMWARE_REVISED_BENCH_CERTIFIEDINCIDENT DATE:
HAPTIC-RUNAWAY: Motorized Fader Haptic Feedback Oscillation Runaway
Lead Investigator: Dr. Tamsin Callow
INCIDENT NARRATIVE
While testing an experimental 16-channel microtonal keyboard console (PROT-035), a software developer increased derivative gain parameters in the motorized fader PID loop. When an operator depressed two adjacent keys simultaneously, the fader motors entered high-frequency mechanical oscillation, chattering violently against aluminum end-stops.
ROOT CAUSE ANALYSIS
Derivative kick caused by capacitive touch sensor noise feeding into the position error loop without low-pass smoothing.
CONTAINMENT PROTOCOL
Added a 40 Hz digital biquad filter to touch sensor readings and implemented hardware current limiters on motor driver H-bridges.
SALVAGED / REASSIGNED HARDWARE
16 Motorized ALPS FadersCapacitive Brass TouchplatesTeensy 4.1 Microcontroller