I found out there is a deadband in my steering controller after several runs. The transfer function for it in the $s$-domain is

$$H(s)=\frac{270\cdot e^{-0.03s}}{0.015\cdot s + 1}$$

To overcome this deadband, should I introduce a compensator? My control theory background is weak so am not sure of a proper way to manage the deadband.


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    $\begingroup$ Use latex style to write equatiions. Transfer function of what? There are comensators like Smith predictor, but I would rather explore where the dead time came from and modify the system. $\endgroup$ – Marko Buršič Feb 25 at 7:41
  • $\begingroup$ Is it dead-time or deadband position from mechanical hysteresis and stiction. ? Can you verify? Deadband can be overcome by reducing actuator slack by design. Also transfer function looks wrong with e^ $\endgroup$ – Sunnyskyguy EE75 Feb 25 at 8:05
  • $\begingroup$ Other answers suggest DITHERING as a cure for deadband. $\endgroup$ – analogsystemsrf Feb 25 at 12:35
  • $\begingroup$ @SunnyskyguyEE75 The exponential $e^{-\tau s}$ just means that there is a time delay of $\tau$ seconds before the output reacts to the input. $\endgroup$ – Koen Tiels Feb 25 at 20:02
  • $\begingroup$ If the deadband excursion time delay is τ = 30ms then f-3dB ~0.3 / 30ms ~ 10Hz and a Gain of 270 or GBW~ 3kHz is unity gain instability frequency so a high order phase lead-lag compensation before 1kHz might work better to inject dither. noise by lead compensation ( HPF gain limited) R1C1//R2C2 ... althoough something tells me GBW ~ 1kHz So start with specs for Response time to step and ramp inputs then overshoot and small step response, reduced deadband, then solve. $\endgroup$ – Sunnyskyguy EE75 Feb 25 at 20:31

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