At present the driving wheel sensor has been designed as single phase optical sensor with low resolution and low ability of anti-jamming and can not distinguish turning direction.It can not meet the need of such circumstances that need high resolution such as the test of instantaneous sliding ratio.So a new plan is designed.In the plan

the sensor signal is first Gray coded before being processed

thus high resolution driving-wheel sensor is performed（32 times are improved）.It improves anti-jamming ability and has the ability of distinguishing turning direction.Meanwhile the process of the photoelectric coder is simplified.