Embedded Delay-Coordinate Predictive Damping for Speed Ripple Attenuation in a Motor–Reducer Flexible Drive

Speed ripple attenuation in geared flexible drives requires control of synchronous components and residual fluctuations within an existing embedded control architecture. This paper develops a five-state delay-coordinate predictive damping controller (D5–PD) that adds auxiliary q-axis current to a proportional–integral (PI)-regulated drive. Direction-specific models are identified from drive speed history and auxiliary current records with exact delay shifts. A three-step output-weighted design is solved offline and deployed as five-coefficient feedback with scalar scheduling and current limits, at a 1 ms auxiliary update period on an F28379D. Experiments compare PI, six-branch multi-resonant control (MR), and D5–PD under six conditions with three runs per controller. At +300 r/min and +1 A, D5–PD reduces mean speed ripple root mean square (RMS) by 38.83% relative to PI and 5.61% relative to MR at nearly equal auxiliary command alternating-current (AC) RMS. Its load current-normalized responses at 2 and 8 Hz are 37.39% and 60.17% lower than MR without disturbance-specific retuning. Total ripple is lower than PI in all six conditions and MR in five; residual RMS is lower than MR throughout. A separate 0.20 A benchmark with six records per method gives 2.12% lower total ripple and 7.68% lower command RMS than proportional ripple damping. These results demonstrate an embedded auxiliary damping implementation and characterize its tradeoffs with frequency-selective and proportional feedback in terms of total ripple, residual fluctuations and command demand.