The dynamics of a platoon of adaptive cruise control vehicles is analyzed fora general mechanical response of the vehicle's power-train. Effects ofacceleration-feedback control that were not previously studied are found. Forsmall acceleration-feedback gain, which produces marginally string-stablebehavior, the reduction of a disturbance (with increasing car number n) isfound to be faster than for the maximum allowable gain. The asymptoticmagnitude of a disturbance is shown to fall off as erf(ct./sq. rt. n) when ngoes to infinity. For gain approaching the lower limit of stability,oscillations in acceleration associated with a secondary maximum in thetransfer function (as a function of frequency) can occur. A frequency-dependentgain that reduces the secondary maximum, but does not affect the transferfunction near zero frequency, is proposed. Performance is thereby improved byelimination of the undesirable oscillations while the rapid disturbancereduction is retained.
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