Characterization, control and testing of an E/H actuator for the development of an autonomous braking system

This thesis aims at designing an autonomous braking control implementable on a real L4 experimental autonomous vehicle. In particular, the main goals are characterizing, controlling and testing a pump to verify its capability to fulfill some desired braking performances. To these purposes, the Dexter electro-hydraulic (E/H) 1600 brake actuator has been used, which is commonly employed in trailer braking systems. In cooperation with the company Bylogix s.r.l., we have developed a brake-by-wire (BBW) solution where the pump, driven by the control unit, directly generates the hydraulic pressure within the brake circuit. A tailor-made test-bench built in collaboration with the company has been used to characterize the actuator. This operation has been carried out by designing a proper acquisition system to allow experimental data collection in Simulink. The utilized device for the acquisition is the USB-6009 board by National Instruments (NI). Due to the non-linearity of the actuator, a gain scheduling (GS) control technique has been adopted. The operating points have been divided in several regions within which has been possible to design a linear PID controller. Moreover, to handle the saturation of the command input, a back-calculation anti-windup technique has been employed. The control algorithm has been developed in Simulink and then implemented and tuned on a CAN control unit through the Eagle programming interface included within the MRS Developer Studio software. Later, both the pump and the controller have been mounted on the vehicle, where the control algorithm has been integrated and adapted to the real system. Finally, different types of tests have been performed, both on the test bench and on the vehicle, to check the quality of the control algorithm under different operating conditions.