A Sensor Fusion Approach to Estimate Clamp Force in Brake-by-Wire Systems

Abstract

Elimination of a clamp force sensor from brake-bywire system designs is strongly demanded due to implementation difficulties and cost issues. In this paper a new method is presented to estimate clamp force based on other sensory information. The proposed estimator fuses the outputs of two models to optimise the root mean square error (RMSE) of estimation. Experimental results show that the estimator can accurately track the true clamp force for high speed cases as demanded by anti-lock braking system (ABS) controls. A training strategy has been used to ensure that the estimator can successfully adapt to frictional variations within the reduction gearing. This paper is concluded with a discussion on the reliability of the developed clamp force estimator.

Estimating clamp force for brake-by-wire systems: Thermal considerations

“…Fig. 4, as provided by Saric et al [4], shows that there is significant change in the characteristic curve depending on the level of pad wear. Therefore, a method to adjust the characteristic curve parameter values is required to handle pad wear.…”

“…Otherwise known as drive-by-wire (DBW), such emerging technologies in the automotive industry will provide faster actuation response times as well as the potential to integrate systems to improve performance [1,2]. The development of various DBW technologies is documented in [3][4][5][6][7]. Brake-bywire (BBW) has already been introduced at a commercial level in vehicles in the form of an electro-hydraulic technology.…”

“…The electromechanical brake (EMB) used for a disc is shown in Fig. 1 as provided by Saric et al [4]. A motor is employed to drive reduction gearing which then leads to an induced clamp force.…”

“…2 as provided by Saric et al [4]. Cascaded force, velocity and current control loops are used with feedback sensors required to measure each of these quantities.…”

“…The relationship that exists between motor angle and induced clamp force can be viewed in Fig. 3 as provided by Saric et al [4]. The motor angle was perturbed in a pseudo-static manor, with a line of best fit applied due to hysteresis effects.…”