Abstract: A method of utilizing previous event feedback information from historical derived hammer velocity data, such as associated with a MIDI record function, for providing non-real-time feedback when controlling actuators. The use of non-real-time feedback within the present invention provides a number of advantages over the use of conventional real-time feedback mechanisms. Utilization of the non-real-time (historical) key actuation information reduces the amount of circuitry necessary for correcting the operation of the actuators (i.e. solenoids) during playback on the instrument. By way of example, a programmable circuit element receives velocity information on previous key strikes for adjusting the actuator velocity output signal which will be generated for future key strikes. The accuracy of key strike normalization provided by this method approaches that which is achievable using real-time feedback, because the velocity profiles for each key remain substantially constant during playback.

Abstract: A method of estimating solenoid heat accumulation and providing output power compensation thereof. The method is particularly well suited for compensating the drive solenoids within a player piano mechanism, or similar. A heat value is maintained for each coil whose accumulated heat is of interest. A quantity of heat is periodically removed from each heat value which corresponds to the level of thermal dissipation for the solenoid during the period. Similarly, a quantity of heat is periodically added to the heat value to account for the power being applied to the active solenoids. A gain compensation value may then be calculated from the heat value and used to temperature compensate the power being applied to the solenoids wherein force roll-off is prevented in response to solenoid use.

Abstract: A method of estimating solenoid heat accumulation and providing output power compensation thereof. The method is particularly well suited for compensating the drive solenoids within a player piano mechanism, or similar. A heat value is maintained for each coil whose accumulated heat is of interest. A quantity of heat is periodically removed from each heat value which corresponds to the level of thermal dissipation for the solenoid during the period. Similarly, a quantity of heat is periodically added to the heat value to account for the power being applied to the active solenoids. A gain compensation value may then be calculated from the heat value and used to temperature compensate the power being applied to the solenoids wherein force roll-off is prevented in response to solenoid use.