Disk Brakes Driven by Piezoelectric Elements

Abstract

This paper deals with a brake device attached to each wheel of small cars as a component of brake-by-wire system. The brake device consists of a disk brake, a piezoelectric pump, two accumulators and a three position solenoid valve. Mathematical model of the brake device, an approximation formula of the clamping force (CF), and a control scheme of the CF are presented. Simulation results show that (1) the CF large enough for small cars is generated by using a multilayerd piezoelectric element of 40 mm diameter, (2) the rise time of the CF is about 0.1 second including the time to contact the disk pad with the disk plate, (3) the formula gives close approximation to the simulated value of CF, and (4) the feedback control of the CF is achieved by using the disturbance observer.