METHOD AND MODULE FOR CONTROLLING A VEHICLE'S SPEED BASED ON RULES AND/OR COSTS

摘要

The invention relates to a method for controlling a vehicle's speed, which method is characterised by: - acquiring a set speed vset for the vehicle; - determining a horizon for the itinerary by means of map data and location data, which horizon comprises one or more route segments with at least one characteristic for each segment; - performing, during each of a number of simulation cycles sj each comprising a number N of simulation steps conducted at a predetermined rate f, the steps of: - making a first prediction of the vehicle's speed vpred_cc along the horizon according to a conventional cruise control when the set speed vset is imparted as a reference speed vref, which first prediction depends on the characteristics of said route segment; - doing a first comparison of the first predicted vehicle speed vpred_cc with at least one of first lower and upper limit values vlim1 and vlim2 which are used to define an engine torque T for use in the next simulation cycle Sj+i; - making a second prediction of the vehicle's speed vpred_mew along the horizon when the vehicle's engine torque T is a value which depends on the result of said first comparison in the immediately preceding simulation cycle Sj-i; - doing a second comparison of the second predicted vehicle speed vpred _Tnew/ with at least one of second lower and upper limit values vmin and vmax which delineate a range within which the vehicle's speed should be; - determining at least one reference value which indicates how the vehicle's speed is to be influenced, on the basis of said second comparison and/or the second predicted vehicle speed vpred_Tnew in this simulation cycle Sj; and - using in a control system of the vehicle said at least one reference value on which the vehicle is then regulated.