SPEED MEASUREMENT ALGORITHM FOR LOW-RESOLUTION MAGNETIC ENCODER OF INDUSTRIAL ELECTRIC VEHICLES

摘要

PURPOSE: A speed measurement method using the low resolution magnetic encoder of an industrial electricity vehicle is provided to improve a speed error generated by the low resolution of a technology magnetic encoder and inaccuracy of the encoder and to improve the ride comfort of the vehicle in low speed driving and high speed driving. CONSTITUTION: Up and down pulse in an encoder is successively grouped to a four pulse unit(S100). Pulse per revolution(Ppr) of the encoder and the average range of a control frequency band are determined(S200). Whenever a pulse raises the determined range, a speed is obtained by obtaining the average range. [Reference numerals] (AA) Start; (BB) End; (S100) Continuously grouping rising and falling pulses in two phases of an encoder to a four pulse unit; (S200) Determining an average range by considering a speed control frequency band and P_pr of the encoder; (S300) Measuring a speed in a method of taking an average while moving a group grouping into the four pulse unit by a pulse unit when a pulse enters as much as a constant range; (S400) Estimating the speed by using overflow of a counter between the previous measured speed and the pulse when the pulse does not enters in a low speed area