Peter Nachtwey
Member
Our product is used to do this sort of thing all the time.
ftp://ftp.deltacompsys.com/public/p...r%20figures.ppt
This is a good example of speed and torque limiting. The top and bottom dog grab the log gently and move the log through the saws. If too much torque is applied, the motors will shear the pins that hold the dogs on the chain. The force that the top dog applies much be enough to hold the log but not so much that it keeps the bottom dog from pushing the log through the saws.
The speed at which the log is moved through the saw varies depending on how much of the saw surface area is in contact with the wood. The holding force must be roughly proportional to the weight of the log. Since each log is different, all these parameter change from log to log. I know this is a compression instead of a tension application but the same principles apply.
If your motion controller can not adjust torque on the fly then I know one that is. It is done all the time. This is often done for fatigue testing. We can control the torgue in nice sineusoidal wave forms if necessary.
Yes you can regulate speed and torque but not to follow two different setpoints. I have this argument all the time with people that think you can control position to a position set point and pressure to a pressure set point at the same time. Normally torque is regulated to achieve the desired speed by controlling acceleration and deceleration. If you adjust torque without regards to speed then you soon will be going at the wrong speed. The same goes for adjusting speed without regards to torque. There can be only one. I like to use a minimum function for speed and torque that way I can limit both.
One can calculate the torque for the hydraulic motor by measuring the differential pressure between the motors A and B port. The hydraulic motors have a PSID to torque constant that allows one to calculate torque.
ftp://ftp.deltacompsys.com/public/p...r%20figures.ppt
This is a good example of speed and torque limiting. The top and bottom dog grab the log gently and move the log through the saws. If too much torque is applied, the motors will shear the pins that hold the dogs on the chain. The force that the top dog applies much be enough to hold the log but not so much that it keeps the bottom dog from pushing the log through the saws.
The speed at which the log is moved through the saw varies depending on how much of the saw surface area is in contact with the wood. The holding force must be roughly proportional to the weight of the log. Since each log is different, all these parameter change from log to log. I know this is a compression instead of a tension application but the same principles apply.
If your motion controller can not adjust torque on the fly then I know one that is. It is done all the time. This is often done for fatigue testing. We can control the torgue in nice sineusoidal wave forms if necessary.
Yes you can regulate speed and torque but not to follow two different setpoints. I have this argument all the time with people that think you can control position to a position set point and pressure to a pressure set point at the same time. Normally torque is regulated to achieve the desired speed by controlling acceleration and deceleration. If you adjust torque without regards to speed then you soon will be going at the wrong speed. The same goes for adjusting speed without regards to torque. There can be only one. I like to use a minimum function for speed and torque that way I can limit both.
One can calculate the torque for the hydraulic motor by measuring the differential pressure between the motors A and B port. The hydraulic motors have a PSID to torque constant that allows one to calculate torque.