Middlesex County, Ontario | A performance shortcoming that comes along with the ATC300 kit is that there is no wheel angle sensor. Any good auto steer system has a wheel angle sensor, basically a pot and a linkage, typically built into the kingpin these days. It gives the system very exact feedback of the exact wheel angle, and it knows the exact wheel angle all the time.
The ATC300 kit doesn't have a wheel angle sensor. It's got a stepper motor driving an orbital. An orbital outputs so many cc of oil per revolution, a stepper motor can be precisely commanded to an exact angle. If you move the stepper so many degrees then the orbital outputs so many cc of oil which moves the steering cylinder so many millimeter which through linkages becomes so many wheel angle degrees. And with calibration of letting it autosteer a bunch of circles, it can do that pretty well. But with ackerman linkage geometry play in things and oil viscosity depending on oil type and temperature and etc it's just never going to be as exact as a proper wheel angle sensor.
And it can only keep track of that wheel angle while it's autosteering. If you grab the wheel and turn, it doesn't know how far you turned the wheel. While you are manually turning, the only thing it can do is track the gyro and guess at wheel angle. When you engage autosteer again, it's going to take awhile to get that wheel angle figured out again.
You know what else operates almost exactly the same way? Every single system that spins a steering wheel. They don't have a wheel angle sensor, the motor spins the orbital, the motor has an encoder and can be precisely commanded to exact angles. It doesn't really know what you're doing when you manually steer and takes a bit to sort itself out when you first engage it. The only extra inaccuracies about the steer wheel systems the play in the steering column joints and maybe wheel slippage (ez steer).
Performance is the same as motorized wheel systems, which is pretty good. It is not capable of being as exact and perfect as a normal autosteer with wheel angle sensor is capable of being. |
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