Editing Control modes
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==Torque control== | ==Torque control== | ||
[[File:Force-torque-wrench.jpg|thumb|140px|Torque]] | [[File:Force-torque-wrench.jpg|thumb|140px|Torque]] | ||
| − | Torque control mode makes motor a torque or force transducer. I.e. user sets torque | + | Torque control mode makes motor a torque or force transducer. I.e. user sets torque reference to 1 Nm, then motor will produce 1 Nm torque regardless of spinning speed. In torque mode user can not set limits to velocity or position. |
;Typical applications | ;Typical applications | ||
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==Velocity control== | ==Velocity control== | ||
[[File:Turning.jpg|thumb|140px|Velocity]] | [[File:Turning.jpg|thumb|140px|Velocity]] | ||
| − | Goal of velocity control is to regulate motor speed. I.e. if user velocity | + | Goal of velocity control is to regulate motor speed. I.e. if user velocity reference is 500 rpm, then motor attempts to rotate exactly at 500 rpm no matter how much load is attached to motor. In velocity mode user can set limits for torque but not for position. |
;Typical applications | ;Typical applications | ||
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==Position control== | ==Position control== | ||
[[File:CartesianRobot.gif|thumb|140px|Position]] | [[File:CartesianRobot.gif|thumb|140px|Position]] | ||
| − | Position control mode attempts to provide precision positioning. Motor follows | + | Position control mode attempts to provide precision positioning. Motor follows reference set point and if set point is kept constant, motor holds position even if external forces attempt to displace it. In position mode user can set limits to torque and velocity. |
;Typical applications | ;Typical applications | ||
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*Robotics | *Robotics | ||
*Welding | *Welding | ||
| − | + | ||
| − | + | ||
| − | + | ||
==Controller structure== | ==Controller structure== | ||
[[File:Cascade position controller.png|thumb|500px|Simplified VSD drive block diagram in position mode. Limiters are not pictured. ]] | [[File:Cascade position controller.png|thumb|500px|Simplified VSD drive block diagram in position mode. Limiters are not pictured. ]] | ||
| − | VSD drives use cascaded controllers. So for example in velocity mode, torque controller and velocity contoller are connected in series so that torque | + | VSD drives use cascaded controllers. So for example in velocity mode, torque controller and velocity contoller are connected in series so that torque reference is generated by velocity controller. Position mode is same as velocity controller except the velocity reference is generated by position controller. |
Cascaded structure leads to more flexible features and enables higher dymamic performance compared to direct PWM or torque control from position controller. | Cascaded structure leads to more flexible features and enables higher dymamic performance compared to direct PWM or torque control from position controller. | ||
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:User torque rererence → Torque limiter → Torque controller outputs motor PWM | :User torque rererence → Torque limiter → Torque controller outputs motor PWM | ||
;Velocity controller stucture | ;Velocity controller stucture | ||
| − | :User velocity | + | :User velocity reference → Velocity limiter → Velocity controller outputs torque rererence → Torque limiter → Torque controller outputs motor PWM |
;Position controller stucture | ;Position controller stucture | ||
| − | :User position | + | :User position reference → Position controller outputs velocity reference → Velocity limiter → Velocity controller outputs torque rererence → Torque limiter → Torque controller outputs motor PWM |
| − | Limiters simply cut and saturate | + | Limiters simply cut and saturate reference signal if user specified torque/velocity limit is exceeded. |
