Title: Musical instrument automatically playing music using a hybrid feedback control loop
Application Number: 200510004119 Application Date: 2005.01.06
Publication Number: 1637849 Publication Date: 2005.07.13
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: G10F1/02
Applicant(s) Name: Yamaha Corp. Address:
Inventor(s) Name: Fujiwara Yuji;Ohba Yasuhiko
Attorney & Agent: di wankui huang xiaolin
Abstract:
    An automatic player piano includes keys (1a, 1b) driven for the angular motion through a hybrid feedback control loop (310); a controller (30), a key position sensor (25), a plunger velocity sensor (35) and a solenoid-operated key actuator (6) form parts of the hybrid feedback control loop for each key (1a, 1b), and a current key position (yxka) and a plunger velocity (yvma) are reported to the controller (30); the controller (30) determines a series of target position (rx) or a reference trajectory and a target velocity (rv), and periodically compares a composite current position (yx) and a composite current velocity (yv), which are determined on the basis of the current key position and current plunger velocity, with the target position (rx) and target velocity (rv) to see whether or not the key (1a, 1b) travels on the reference trajectory; if the answer is negative, the controller (30) adjusts the driving signal to a proper duty ratio so as to force the key (1a, 1b) to travel on the reference trajectory.
Time: 6