robot balance accelerometer gyro kalman

inverted pendulum balancing robot using rate gyro and accelerometer with kalman filter, dspic33 MC 804, loop speed 1200hz, using DMA uart debug increased loop speed from 250hz to 1.2Khz, no RTOS. C. 40MIPS, heds 360ppr encoders on wheels, gearmotors 29:1 6W,6V,MAXON standard DC.adxl345,arctanx,y for angle, st rate gyro via 10bit ADC.MC33887 motor drivers. custom pcb from eagle.6AA 2.5Ah low discharge cells balance and motor PID loops, motor pwm at 2Khz, it screams!, motor drive pwm on/open, no short.