Full-time anti-sway control method of bridge crane system based on inverter structure

1. A full-time anti-sway control method of a bridge crane system based on an inverter structure, the bridge crane system comprising an inverter for performing the control method and at least one motor controlled by the control method, the control method comprising steps of:

receiving a specified high frequency command and a frequency change time, wherein the frequency change time is an acceleration and deceleration time,

calculating a time setting range according to a plurality of system parameters and a rope length information of the bridge crane system, wherein the time setting range is the acceleration and deceleration time, wherein

t

acc

/

dec

≥

J

sys

×

ω

rate

2

⁢

T

rate

⁢

and

⁢

t

acc

/

dec

≤

0.9

T

swing

2

,

 where t acc/dec is the time setting range, ω rate is a rated speed, T rate is a rated torque, J sys is a system inertia, T swing is a natural swing period,

selecting a time setting value within the time setting range,

dividing the frequency change time into a plurality of time intervals according to the time setting value,

adjusting an operation frequency command to change between a low frequency command and the specified high frequency command within the plurality of time intervals to generate a frequency change curve,

estimating a swing angle and a swing speed by a swing angle estimation module in a sensorless manner according to the frequency change curve, a gravitational acceleration constant, and the rope length information,

designing a swing angle processing module according to the gravitational acceleration constant and the rope length information,

generating a frequency correction amount by the swing angle processing module according to the swing angle and the swing speed, and

superimposing the frequency change curve and the frequency correction amount to generate an anti-sway frequency command to drive the at least one motor.

2. The full-time anti-sway control method as claimed in claim 1 , further comprising steps of:

calculating a lower limit value of the time setting range according to the system parameters of the bridge crane system,

calculating a natural swing period of a bridge crane under a simple pendulum movement according to the rope length information of the bridge crane system, and

calculating an upper limit value of the time setting range according to the natural swing period.

3. The full-time anti-sway control method as claimed in claim 1 , further comprising steps of:

using the time setting value as an acceleration time and a deceleration time in the plurality of time intervals, and

acquiring a maintain time of the plurality of time intervals according to the frequency change time and the time setting value, wherein the maintain time is between the acceleration time and the deceleration time.

4. The full-time anti-sway control method as claimed in claim 3 , wherein the frequency change curve linearly increases from the low frequency command to the specified high frequency command, and after the frequency change curve maintains at the maintain time with the specified high frequency command, the frequency change curve linearly decreases from the specified high frequency command to the low frequency command.

5. The full-time anti-sway control method as claimed in claim 2 , further comprising:

calculating a frequency change amount of the operation frequency command within the frequency change time according to the frequency change curve,

calculating the swing angle of the bridge crane under the simple pendulum movement according to the rope length information and the frequency change amount, and

calculating the swing speed of the bridge crane under the simple pendulum movement according to the swing angle.

6. The full-time anti-sway control method as claimed in claim 5 , further comprising:

calculating a response frequency according to the natural swing period and a bandwidth ratio,

calculating a first control parameter according to the response frequency, a damping coefficient, and the rope length information,

calculating a second control parameter according to the response frequency and the rope length information,

calculating a control variable according to the swing angle, the swing speed, and the first control parameter,

multiplying the control variable with the second control parameter to acquire a rotation speed correction amount, and

acquiring the frequency correction amount according to the rotation speed correction amount.

7. The full-time anti-sway control method as claimed in claim 3 , wherein the anti-sway frequency command nonlinearly increases from the low frequency command to the specified high frequency command, and after the anti-sway frequency command maintains at the specified high frequency command for a period of time, the anti-sway frequency command nonlinearly decreases from the specified high frequency command to the low frequency command.

8. A full-time anti-sway control method of a bridge crane system based on an inverter structure, the bridge crane system comprising an inverter for performing the control method, a position sensor, and at least one motor controlled by the control method, the control method comprising steps of:

receiving a specified high frequency command and a frequency change time, wherein the frequency change time is an acceleration and deceleration time,

calculating a time setting range according to a plurality of system parameters and a rope length information of the bridge crane system, wherein the time setting range is the acceleration and deceleration time, wherein

t

acc

/

dec

≥

J

sys

×

ω

rate

2

⁢

T

rate

⁢

and

⁢

t

acc

/

dec

≤

0.9

T

swing

2

,

 where t acc/dec is the time setting range, ω rate is a rated speed, T rate is a rated torque, J sys is a system inertia, T swing is a natural swing period,

selecting a time setting value within the time setting range,

dividing the frequency change time into a plurality of time intervals according to the time setting value,

adjusting an operation frequency command to change between a low frequency command and the specified high frequency command within the plurality of time intervals to generate a frequency change curve,

acquiring a rotation angle of the at least one motor by the position sensor,

estimating a swing angle and a swing speed by a swing angle estimation module in a sensorless manner according to the frequency change curve, a gravitational acceleration constant, and the rope length information,

designing a swing angle processing module by the gravitational acceleration constant and the rope length information,

generating a frequency correction amount by the swing angle processing module according to the swing angle and the swing speed, and

superimposing the frequency change curve and the frequency correction amount to generate an anti-sway frequency command to drive the at least one motor.

9. The full-time anti-sway control method as claimed in claim 8 , further comprising steps of:

calculating a lower limit value of the time setting range according to the system parameters of the bridge crane system,

calculating a natural swing period of the bridge crane under the simple pendulum movement according to the rope length information of the bridge crane system, and

calculating an upper limit value of the time setting range according to the natural swing period.

10. The full-time anti-sway control method as claimed in claim 8 , further comprising steps of:

using the time setting value as an acceleration time and a deceleration time in the plurality of time intervals, and

acquiring a maintain time of the plurality of time intervals according to the frequency change time and the time setting value, wherein the maintain time is between the acceleration time and the deceleration time.

11. The full-time anti-sway control method as claimed in claim 10 , wherein the frequency change curve linearly increases from the low frequency command to the specified high frequency command, and after the frequency change curve maintains at the maintain time with the specified high frequency command, the frequency change curve linearly decreases from the specified high frequency command to the low frequency command.

12. The full-time anti-sway control method as claimed in claim 9 , further comprising:

calculating a frequency change amount of the operation frequency command within the frequency change time according to the frequency change curve,

calculating the swing angle of the bridge crane under the simple pendulum movement according to the rope length information and the frequency change amount, and

calculating the swing speed of the bridge crane under the simple pendulum movement according to the swing angle.

13. The full-time anti-sway control method as claimed in claim 12 , further comprising:

calculating a response frequency according to the natural swing period and a bandwidth ratio,

calculating a first control parameter according to the response frequency, a damping coefficient, and the rope length information,

calculating a second control parameter according to the response frequency and the rope length information,

calculating a control variable according to the swing angle, the swing speed, and the first control parameter,

multiplying the control variable with the second control parameter to acquire a rotation speed correction amount, and

acquiring the frequency correction amount according to the rotation speed correction amount.

14. The full-time anti-sway control method as claimed in claim 10 , wherein the anti-sway frequency command nonlinearly increases from the low frequency command to the specified high frequency command, and after the anti-sway frequency command maintains at the specified high frequency command for a period of time, the anti-sway frequency command nonlinearly decreases from the specified high frequency command to the low frequency command.