Collaborative control of a dual brake system a rear-wheel-drive electric vehicle

What is it about?

A control method is proposed to control in a collaborative manner the regenerative brake and the electro-hydraulic brake of an electric vehicle with a sole brake pedal as input. It combines the tracking of an ideal brake force distribution an an imrpovement to the potential of energy recovery. This, by a proper control of the on/off solenoid valve within the electro-hydraulic brake system.

Featured Image

Why is it important?

By the proper regulation of the target brake pressure through the EHB controller design, the energy recovered can be increased. This is achieved by the two following actions: (1) the tracking of the I-curve which increases the rear brake force compared to a standard distribution and (2) the maximum allocation of the RB brake force at the rear wheel instead of the EHB brake force. Also, since the front wheel brake pressure is not modulated and the rear brake pressure is unnecessary in a lot of cases, this leads to good robustness. Furthermore, a novel method to fine-tune the caliper hydraulic brake pressure is proposed. A low-frequency PWM signal is applied to the on/off solenoid valve for which the duty cycle is controlled via a simple proportional feedback controller. Thus, the PWM signal generates a complete travel of the valve stroke between the time ‘‘on’’ and time ‘‘off.’’

Perspectives