Forced steering is the steering the trailer does because of the steering linkage or in case of pure electronically steered trailers because of the steering function the manufacturer implemented (without being steered by remote control). Forced steering always depends on a relation between the bending angle and the steering angle, given that the bending angle is the angle between the longitudinal axis of the trailer and the longitudinal axis of the previous vehicle or the load
Manual steering is what you do when you steer the trailer independently via remote control
Friction based steered axles steer because of the friction. The steering behavior of these axles simply follows the law of Ackermann, like the shopping cart
Max. bend angle: The bend angle is the angle between the longitudinal axis of the previous vehicle (e.g. tractor) and the longitudinal axis of the trailer. Maximum value is counted from straight ahead to one side.