Abstract: An angle sensor for measuring an angle .theta. between two rigid bodies rotatably joined at a joint. The angle sensor includes an indicator disk, an anchor strap and a reading means for reading the indicator disk. Our invention also includes forward and backward motion steering control systems which can employ the angle sensor as a hitch angle sensor to measure the hitch angle between a tow vehicle and a trailer.

Abstract: An angle sensor for measuring an angle .theta. between two rigid bodies rotatably joined at a joint. The angle sensor includes an indicator disk, an anchor strap and a mechanism for reading the indicator disk. Our invention also includes forward and backward motion steering control systems which can employ the angle sensor as a hitch angle sensor to measure the hitch angle between a tow vehicle and a trailer.

Abstract: An improved rear steering control system employing separate closed-loop feedback controller and open-loop feedforward control paths. The response characteristics of the open-loop and closed-loop control paths are separately scheduled to optimize the overall system performance. In particular, the authority and delay properties of the two paths are independently varied to achieve desired control objectives. As a result, the advantages of both open-loop and closed-loop control are achieved with a single control system.

Abstract: The driver steering inputs of a closed-loop reference model rear vehicle steering system are measured and subjected to a filter function that delays application of the measured input to the reference model. Externally generated steering inputs appearing in the parameters measured for closed-loop control are subjected to a different filter function which imparts only minimal delay of the signal transmission. As a result, the rear steer control responds at a first, relatively slow rate to driver steering inputs, and a second, relatively fast rate to externally generated disturbances.