Band limited control of a flexible structure using piecewise trigonometric input signals

A method of generating a piecewise trigonometric function of time for use as an input signal in a system, the input signal producing voltages within the system, the piecewise trigonometric function of time being specified by values representing a final time, a switch time, an acceleration amplitude, and a deceleration amplitude, the values being contained in a memory, the method comprising the steps of iteratively:

• (a) choosing an acceleration amplitude and a deceleration amplitude;
• (b) obtaining the switch time and final time for the chosen acceleration and deceleration amplitude;
• and
• (c) adjusting the acceleration amplitude and deceleration amplitude until the system operates within predetermined operating conditions, comprising the steps of:
• (i) determining peak positive and negative applied voltages resulting from the input signal;
• and
• (ii) adjusting the acceleration amplitude and deceleration amplitude until the peak positive and negative applied voltages lie within predetermined respective voltage ranges.

A method of using a motor to move a movable member comprising the steps of:

• providing data related to a desired final position of the movable member;
• obtaining a switch time parameter and a final time parameter corresponding to the data related to the desired final position of the movable member;
• generating an input signal using the switch time and final time parameters to specify a piecewise trigonometric function of time for said input signal, the piecewise trigonometric function of time comprising concatenated cosine and constant functions, the switch time parameter specifying a time at which the input signal changes polarity, and the final time parameter specifying a time at which the input signal is no longer generated;
• feeding the input signal to the motor;
• and
• driving the motor in accordance with the fed input signal to move the movable member to the desired final position.

A method of using a motor to move a movable member comprising the steps of:

• providing data related to a desired final position of the movable member;
• obtaining a switch time parameter, a final time parameter, an acceleration amplitude parameter, and a deceleration amplitude parameter corresponding to the data related to the desired final position of the movable member;
• generating an input signal using the switch time, final time, acceleration amplitude, and deceleration amplitude parameters to specify a piecewise trigonometric function of time as said input signal, the piecewise trigonometric function of time comprising concatenated cosine and constant functions, the switch time parameter specifying a time at which the input signal changes polarity, and the final time parameter specifying a time at which the input signal is no longer generated;
• feeding the input signal to the motor;
• and
• driving the motor in accordance with the fed input signal to move the movable member to the desired final position.

An apparatus for using a motor to move a movable member comprising:

• means for providing data related to a desired final position of the movable member;
• means responsive to the data for providing a switch time parameter and a final time parameter corresponding to the data related to the desired final position;
• means for generating an input signal using the switch time and final time parameters to specify a piecewise trigonometric function of time as said input signal, the piecewise trigonometric function of time comprising concatenated cosine and constant functions, the switch time parameter specifying a first time at which the input signal changes polarity, and the final time parameter specifying a second time at which the input signal is no longer generated;
• and
• means for feeding the input signal to the motor to move the movable member to the desired final position.

An apparatus for using a motor to move a movable member comprising:

• means for providing data related to a desired final position of the movable member;
• means responsive to the data for providing a switch time parameter, a final time parameter, an acceleration amplitude parameter, and a deceleration amplitude parameter corresponding to the data related to the desired final position;
• means for generating an input signal using the switch time, final time, acceleration amplitude, and deceleration amplitude parameters to specify a piecewise trigonometric function of time as said input signal, the piecewise trigonometric function of time comprising concatenated cosine and constant functions, the switch time parameter specifying a first time at which the input signal changes polarity, and the final time parameter specifying a second time at which the input signal is no longer generated;
• and
• means for feeding the input signal to the motor to move the movable member to the desired final position.

Apparatus for using a motor to move an actuator arm in a disk drive member comprising:

• means for providing data related to a desired final position of the actuator arm;
• a memory coupled to the means for providing data, said memory storing a switch time parameter, a final time parameter, an acceleration amplitude parameter, and a deceleration amplitude parameter corresponding to the data;
• means coupled to said memory for generating an input signal using the switch time, final time, acceleration amplitude, and deceleration amplitude parameters to specify a piecewise trigonometric function of time as said input signal, the switch time parameter specifying a first time at which the input signal changes polarity, and the final time parameter specifying a second time at which the input signal is no longer generated;
• means responsive to the generated input signal for providing a predicted position signal for the actuator arm;
• means for providing an actual position signal for the actuator arm by detecting the present position of the actuator arm;
• means for comparing the actual position signal to the predicted position signal to provide an error position signal;
• means for generating an input adjustment signal in response to said error signal;
• means for comparing said input adjustment signal and said generated input signal to provide a corrected input signal;
• and
• means for feeding the corrected input signal to a motor to move the actuator arm.

A method of generating a piecewise trigonometric function of time comprising concatenated cosine and constant functions, for use as an input signal in a system including a motor driven by the input signal for moving a movable member, the piecewise trigonometric function of time being specified by values representing a final time, a switch time, an acceleration amplitude, and a deceleration amplitude, the values being contained in a memory, the method comprising the steps of iteratively:

• (a) choosing an acceleration amplitude and a deceleration amplitude;
• (b) obtaining the switch time and final time for the chosen acceleration and deceleration amplitudes;
• and
• (c) adjusting the acceleration amplitude and deceleration amplitude until the system operates within predetermined operating conditions.

A method of generating a piecewise continuous function of time for use as an input signal in a system, the input signal producing voltages within the system, the piecewise trigonometric function of time being specified by values representing a final time, a switch time, an acceleration amplitude, and a deceleration amplitude, the values being contained in a memory, the method comprising the steps of:

• (a) choosing an acceleration amplitude and a deceleration amplitude;
• (b) obtaining the switch time and final time for the chosen acceleration and deceleration amplitudes;
• (c) determining peak positive and negative applied voltages resulting from the input signal;
• (d) increasing the acceleration amplitude if the peak positive applied voltage is less than a positive voltage limit minus a voltage tolerance;
• (e) decreasing the acceleration amplitude if the peak positive applied voltage is greater than the positive voltage limit plus the voltage tolerance;
• (f) holding the acceleration amplitude if the positive voltage limit minus the voltage tolerance is less than the positive applied voltage, and the positive voltage limit plus the voltage tolerance is greater than the positive applied voltage;
• (g) increasing the deceleration amplitude if the peak negative applied voltage is less than a negative voltage limit minus the voltage tolerance;
• (h) decreasing the deceleration amplitude if the peak negative applied voltage is greater than the negative voltage limit plus the voltage tolerance;
• and
• (i) holding the deceleration amplitude if the negative voltage limit minus the voltage tolerance is less than the negative applied voltage, and the negative voltage limit plus the voltage tolerance is greater than the negative applied voltage.