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

The use of a stiffness curve, otherwise known as the characteristic curve, to estimate clamp force for a brake-by-wire system has been the subject of past research. The requirement to estimate clamp force arises from trying to make the conventional use of a clamp force sensor a redundant component and thereby reduce costs. Previous uses of the characteristic curve do not effectively model parameter variations in response to heating effects. This paper presents foundations for a new approach to model the changes in characteristic curve parameter values under the influence of heating. The new approach centers on predicting pad temperatures and using this data to appropriately adjust characteristic curve parameter values. Two temperature sensors are required to be employed in this new approach. These additional sensors will not have a considerable impact towards the cost savings created by omitting a clamp force sensor. Finally experimental verifications are provided as well as recommendations for further research.