Abstract:

A clamping force estimation and control strategy for electro-mechanical braking system was proposed to meet the demand for high accuracy and fast response of braking system for autonomous vehicles. A double seventh degree polynomial was used to realize the envelope estimation of the clamping force, by fitting the polynomial curves during the clamping and releasing processes and introducing the first-order inertial link to describe the hysteresis characteristics at different releasing points, and a feed-forward dual-loop proportional-integral-derivative (PID) control method of the clamping force was designed to realize the high accuracy and fast response of the clamping force. The results show that the maximum error of the clamping force estimation is 528.17 N, and the estimation error is controlled within 4.40%; the control error is 270 N under four typical signals, and the error is controlled within 2.25%. The estimation and control strategy has good estimation and control accuracy under complex working conditions, and the fast response speed also enhances the reliability of the electro-mechanical braking system.

Key words: electro-mechanical brake, clamping force estimation, feed-forward dual-loop proportional-integral-derivative (PID) control, inertia link