Abstract: Methods and apparatus for concentration determination using polarized light. The apparatus includes a first polarized light source having a first light source polarization axis and a second polarized light source having a second light source polarization axis generally perpendicular to the first light source polarization axis. Also, a first polarized light receiver having a first polarized light receiver polarization axis and configured to measure an intensity of light transmitted from the first light receiver polarizer and a second polarized light receiver having a second polarized light receiver polarization axis substantially perpendicular to the first light receiver polarization axis and configured to measure an intensity of light transmitted from the second light receiver polarizer, wherein the first and second light receiver polarization axes are generally +/?45 degrees relative to the first and second light source polarization axes.

Abstract: An audio alarm for a transporter having an electric motor. The alarm has a signal generator for generating a signal within the audible frequency range and a modulator for modulating a current that is applied to the electric motor in accordance with the signal generated by the signal generator.

Abstract: An audio alarm for a transporter having an electric motor. The alarm has a signal generator for generating a signal within the audible frequency range and a modulator for modulating a current that is applied to the electric motor in accordance with the signal generated by the signal generator.

Abstract: Methods and apparatus for concentration determination using polarized light. The apparatus includes a first polarized light source having a first light source polarization axis and a second polarized light source having a second light source polarization axis generally perpendicular to the first light source polarization axis. Also, a first polarized light receiver having a first polarized light receiver polarization axis and configured to measure an intensity of light transmitted from the first light receiver polarizer and a second polarized light receiver having a second polarized light receiver polarization axis substantially perpendicular to the first light receiver polarization axis and configured to measure an intensity of light transmitted from the second light receiver polarizer, wherein the first and second light receiver polarization axes are generally +/?45 degrees relative to the first and second light source polarization axes.

Abstract: Methods and apparatus for detecting a sensor angle error in a system in which a measured quantity is determined on the basis of a phase of a signal. A signal derived from the measurement of multiple sensors is ascribed to a vector in a two-dimensional space, and a norm is calculated characterizing that vector. A value is calculated characterizing variation of that norm over a specified period of time and that value is compared with a threshold in order to identify a sensor fault.

Abstract: An electric device includes a motor and a motor drive for commanding a torque generated by the motor. A fault control circuit detects a fault condition associated with the motor drive. Upon detection of the fault condition, the fault control circuit adjusts the torque commanded by the motor drive.

Abstract: A system and method for generating commands for current subject to dynamic determinations of a limit. In one embodiment, the dynamically determined limit is a function of power dissipation in a component estimated from a measured current level and as a function of a measured temperature proximate to the component. In another embodiment, the limit is a lesser of two dynamically determined current levels. The system and method may be of particular use in a motor having limits determined with respect to a transistor and a motor winding. More particularly, estimated temperatures are established for a transistor and a motor winding for use in dynamically determining limits. Dynamic current limiting may be applied to a left and right wheeled vehicle such that the limit applied to both wheels is the lower of the limits dynamically determined for each wheel.

Abstract: An electric device includes a motor and a motor drive for commanding a torque generated by the motor. A fault control circuit detects a fault condition associated with the motor drive. Upon detection of the fault condition, the fault control circuit adjusts the torque commanded by the motor drive.

Abstract: A personal transporter device and corresponding method of operation are given that utilize an exercise mode. A transporter assembly includes a platform, a ground-contacting module, and a motorized drive. The platform supports a user. The ground-contacting module is connected to the platform. The motorized drive powers the ground-contacting module to drive the assembly in a selected direction over an underlying surface. A controller is coupled to and controlling the motorized drive, and also has an exercise mode for opposing a user-provided human power input with a selected level of resistance. When the device is a dynamically stabilized transporter, the controller also controls the motorized drive so as to dynamically stabilize the transporter assembly.

Abstract: A personal transporter device and corresponding method of operation are given that utilize an exercise mode. A transporter assembly includes a platform, a ground-contacting module, and a motorized drive. The platform supports a user. The ground-contacting module is connected to the platform. The motorized drive powers the ground-contacting module to drive the assembly in a selected direction over an underlying surface. A controller is coupled to and controlling the motorized drive, and also has an exercise mode for opposing a user-provided human power input with a selected level of resistance. When the device is a dynamically stabilized transporter, the controller also controls the motorized drive so as to dynamically stabilize the transporter assembly.

Abstract: An electric device includes a motor and a motor drive for commanding a torque generated by the motor. A fault control circuit detects a fault condition associated with the motor drive. Upon detection of the fault condition, the fault control circuit adjusts the torque commanded by the motor drive.