Abstract: A drive system comprises at least two electric motor subassemblies, each comprising a rotor and a stator. The rotors are connected to a mechanical load to fix a position between the two rotors. The system further comprises: first and second position sensing assemblies that provide first and second rotor position signals of first and second motor subassemblies, respectively. Each position signal is indicative of the position of the associated rotor relative to its associated stator including a periodic pattern of errors in the indicated position of the rotor. A motor controller controls the currents applied to each motor subassembly as a function of the position signal.

Abstract: A handwheel actuator assembly for a steer-by-wire system of a vehicle comprises a housing, a shaft rotatably mounted to the housing, the shaft connectable to a handwheel, and one or more motors each having a stator and a rotor. The stator carries a plurality of phase windings and the rotor carries a plurality of magnet poles and is connected to the shaft. A control circuit is adapted to control the current flowing into or out of each motor to cause a net torque to be applied to the shaft during normal operation. The stator of at least one of the motors is configured such that in the event that the control circuit is powered down or disconnected and the handwheel is rotated at 180 degrees per second, the combination of motors overall provides a drag torque of at least 50 percent of the resistance to rotation of the shaft and a torque at the handwheel of at least 2 Nm.

Abstract: A magnetic encoder includes one or more sensors and an encoder element having at least two tracks of encoder regions. Each region comprises a magnetic pole. Each sensor has one or more sensing elements associated with a respective track and generates an output that is indicative of the magnetic field associated with that track. At least one track has a differing number of poles to at least one of the other tracks. The properties of the poles of a first one of the tracks differ along the track such that there is a periodic variation along the first track of the magnetic field emitted by the first track that is detected by the sensing elements associated with the first track which at least partially cancels out a corresponding periodic variation in field from the other tracks that is also detected by the sensing elements associated with the first track.

Abstract: A magnetic encoder comprising an encoder element having at least two tracks of encoder regions, each region comprising a magnetic pole, the poles along each track being arranged as an alternating pattern of North and South poles, and one or more sensors, each sensor comprising one or more sensing elements associated with a respective track and generating an output that is indicative of the magnetic field associated with that track in the vicinity of the sensor, in which at least one track has a differing number of poles to at least one of the other tracks, and in which the properties of the poles of a first one of the tracks differ along the track such that there is a periodic variation along the first track of the magnetic field emitted by the first track that is detected by the sensing elements associated with the first track which at least partially cancels out a corresponding periodic variation in field from the other tracks that is also detected by the sensing elements associated with the first track.

Abstract: A magnetic encoder comprising an encoder element having at least two tracks of encoder regions, each region comprising a magnetic pole, the poles along each track being arranged as an alternating pattern of North and South poles, and one or more sensors, each sensor comprising one or more sensing elements associated with a respective track and generating an output that is indicative of the magnetic field associated with that track in the vicinity of the sensor, in which at least one track has a differing number of poles to at least one of the other tracks, and in which the properties of the poles of a first one of the tracks differ along the track such that there is a periodic variation along the first track of the magnetic field emitted by the first track that is detected by the sensing elements associated with the first track which at least partially cancels out a corresponding periodic variation in field from the other tracks that is also detected by the sensing elements associated with the first track.

Abstract: A magnetic encoder comprising an encoder element having at least two tracks of encoder regions, each region comprising a magnetic pole, the poles along each track being arranged as an alternating pattern of North and South poles, and one or more sensors, each sensor comprising one or more sensing elements associated with a respective track and generating an output that is indicative of the magnetic field associated with that track in the vicinity of the sensor, in which at least one track has a differing number of poles to at least one of the other tracks, and in which the properties of the poles of a first one of the tracks differ along the track such that there is a periodic variation along the first track of the magnetic field emitted by the first track that is detected by the sensing elements associated with the first track which at least partially cancels out a corresponding periodic variation in field from the other tracks that is also detected by the sensing elements associated with the first track.