Editing Tuning torque controller
Your changes will be displayed to readers once an authorized user accepts them. (help) |
Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.
The edit can be undone.
Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision | Your text | ||
Line 1: | Line 1: | ||
− | + | Torque controller tuning means finding the correct gain values for a torque controller inside the servo drive to achieve a proper response from a torque [[Setpoint signal|setpoint]] change. | |
− | + | ||
− | + | ||
==Direct inductance & resistance setting method== | ==Direct inductance & resistance setting method== | ||
In [[Granity]], there is no dedicated torque control PI gains as the software supports entering motor coil inductance and resistance where the suitable PI gains are calculated from. | In [[Granity]], there is no dedicated torque control PI gains as the software supports entering motor coil inductance and resistance where the suitable PI gains are calculated from. | ||
− | + | If your motor comes with coil specifications containing [[phase-to-phase]] inductance and resistance values, then the only necessary step is to enter the given values into motor resistance [[MR]] and inductance [[ML]] parameter fields. In case of troubles with this method, proceed with manual tuning method. | |
− | If | + | |
− | + | ||
− | + | ||
− | + | ||
==Manual tuning method== | ==Manual tuning method== | ||
− | Manual tuning of torque controller is some times done in order to optimize the torque controller response or to find the correct motor | + | Manual tuning of torque controller is some times done in order to optimize the torque controller response or to find the correct motor resistance [[MR]] and inductance [[ML]] parameters if unknown. Manual tuning also usually yields better torque response than the direct method which may help tuning of velocity or position tuning. |
{{tip|If satisfactory performance was achieved by direct inductance & resistance setting method, you may skip the manual tuning method.}} | {{tip|If satisfactory performance was achieved by direct inductance & resistance setting method, you may skip the manual tuning method.}} | ||
− | In order to change torque tuning, one needs to change motor | + | In order to change torque tuning, one needs to change motor resistance [[MR]] and inductance [[ML]] parameters until the torque response looks satisfactory. |
===Preparations=== | ===Preparations=== | ||
[[File:Torqgoodwithtestingtab.png|thumb|Correct torque tuning settings on the Testing tab.]] | [[File:Torqgoodwithtestingtab.png|thumb|Correct torque tuning settings on the Testing tab.]] | ||
Line 22: | Line 16: | ||
*Fix the motor shaft so that it cannot rotate under full peak torque of the motor | *Fix the motor shaft so that it cannot rotate under full peak torque of the motor | ||
*Make following parameter changes to Granity and click apply afterwards: | *Make following parameter changes to Granity and click apply afterwards: | ||
− | **Set drive in torque control mode | + | **Set drive in torque control mode [[CM]] |
− | **Set | + | **Set torque bandwidth limit [[TBW]] to maximum |
− | **Choose ''Serial only'' setpoint input | + | **Choose ''Serial only'' setpoint input [[CM]] |
− | **Untick | + | **Untick Setpoint smoothing [[CIS]] |
− | **Set Goals tab | + | **Set Goals tab [[DIV]] and [[MUL]] to 50 |
**Make other necessary adjustments to have drive powered and enabled | **Make other necessary adjustments to have drive powered and enabled | ||
*Set-up the test stimulus and capture settings from Testing tab: | *Set-up the test stimulus and capture settings from Testing tab: | ||
− | **Set target setpoint 1 [[TSP1]] to | + | **Set target setpoint 1 [[TSP1]] to 5000-15000 |
**Set delay 1 [[TSD1]] to 0.05 seconds | **Set delay 1 [[TSD1]] to 0.05 seconds | ||
**Set target setpoint 2 [[TSP2]] to 0 | **Set target setpoint 2 [[TSP2]] to 0 | ||
− | **Set delay1 [[ | + | **Set delay1 [[STD2]] to 0.5 s |
− | **Choose sample rate | + | **Choose sample rate [[TSR]] of 10000 Hz or more |
**Choose ''Capture setpoint change ind positive direction'' from the dropdown | **Choose ''Capture setpoint change ind positive direction'' from the dropdown | ||
**''Tick Continuously repeating capture'' | **''Tick Continuously repeating capture'' | ||
**Tick ''Torque setpoint'' and ''Torque achieved'' from signals | **Tick ''Torque setpoint'' and ''Torque achieved'' from signals | ||
**Tick ''Start capture'' to begin continous capture. | **Tick ''Start capture'' to begin continous capture. | ||
− | **Tick | + | **Tick Enable test stimulus [[TSE]] to begin a pulsed torque generation |
Once the steps above are done, motor should be generating short torque pulses to a fixed shaft and torque response graphs should appear on the right side of Granity about once in 3-5 seconds. | Once the steps above are done, motor should be generating short torque pulses to a fixed shaft and torque response graphs should appear on the right side of Granity about once in 3-5 seconds. | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
===Adjusting MR and ML to for optimum torque control=== | ===Adjusting MR and ML to for optimum torque control=== | ||
− | The task here is to adjust the | + | The task here is to adjust the [[MR]] and [[ML]] parameters to achieve near optimum step response for the torque controller. Observe the images below for guidance. |
− | + | If the drive faults during this testing due to overcurrent, try reducing [[TSP1]] value or increase fault current tolerance [[FOC]] parameter, click Apply, and clear drive faults via the Connect tab. | |
[[File:TorqlowR.png|800px|]] | [[File:TorqlowR.png|800px|]] | ||
− | In this case the | + | In this case the resistance [[MR]] value has been set too low causing slowly rising achieved torque curve. Such slow response would reduce servo responsiveness. |
[[File:TorqhighR.png|800px|]] | [[File:TorqhighR.png|800px|]] | ||
− | In the opposite case (too high | + | In the opposite case (too high [[MR]] value) the response shows wavy oscillations and ovesrhoot. |
[[File:TorqlowL.png|800px|]] | [[File:TorqlowL.png|800px|]] | ||
− | Same kind of phenomenon will be seen if motor | + | Same kind of phenomenon will be seen if motor inductance [[ML]] value is too low. Finding oscillation free tuning is finding the correct balance between the MR and ML as both affect each other. |
[[File:TorqhigL.png|800px|]] | [[File:TorqhigL.png|800px|]] | ||
− | Too high | + | Too high inductance [[ML]] will cause sharp overshooting and high frequency oscillations. Motor may produce audible noise if oscillations are continuous (occurs with way too high ML). |
[[File:Torqgood.png|800px|]] | [[File:Torqgood.png|800px|]] | ||
Line 76: | Line 64: | ||
[[File:Torqgoodspinning.png|800px|]] | [[File:Torqgoodspinning.png|800px|]] | ||
− | The above image shows what may happen if motor shaft is not fixed properly (allowed to rotate). This is | + | The above image shows what may happen if motor shaft is not fixed properly (allowed to rotate). This is withe the optimum settings like the previous image. |
===Steps to do after manual tuning finished=== | ===Steps to do after manual tuning finished=== | ||
− | *Stop test stimulus by unticking | + | *Stop test stimulus by unticking [[TSE]] |
*Stop scope catpure by unticking ''Continuously repeating capture'' | *Stop scope catpure by unticking ''Continuously repeating capture'' | ||
− | *Undo all temporary changes made to settings (such as | + | *Undo all temporary changes made to settings (such as [[TBW]], [[CM]], [[DIV]], [[MUL]]) but leave the optimized [[MR]] and [[ML]] values active |
*Save settings to drive memory by clicking ''Save settings on drive non-volatile memory'' button | *Save settings to drive memory by clicking ''Save settings on drive non-volatile memory'' button | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− |