Mapping and correction of torque ripple in brushless electric motors

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Haptic feedback is the most direct way that a physical device can communicate with a user. It triggers a primitive part of the brain that processes faster than auditory or visual stimulation. Since humans have a high sensitivity to physical stimulation, small discrepancies in force output of haptic devices are perceivable and can interfere with the intended feedback. Electric motors employ magnetic fields as a mean to impart haptic forces onto users. Since magnetic fields are highly non-linear in nature, imparting predictable forces that are consistent for all positions of the motor has been a difficult task. Modern techniques commonly employ expensive mechanical and electrical solutions to this problem. Such solutions are rarely feasible in the consumer market, making haptic feedback systems only prominent in industry. If the cost were reduced and value was increased of haptic controllers, more of the world could take advantage of this powerful feedback for a variety of applications. In order to increase the tactile feeling of haptic controllers while reducing their cost, a test bench will be built that can map the force output of a variety of motors. This data will be saved into a microcontroller that will use it along with position sensor information to control the motor in a smooth, linear fashion with respect to torque. This method differs from common commutation techniques as it employs a logic-based distribution system based on empirical test result, rather than a wave-form-based distribution system based on highly simplified electro-magnetic theory.