DRV10983EVM: problems when quick drive up to closed loop, peak torque

Hey Ulascan,

Let me address your questions/comments:

1. The first problem is at the drive up the Motor in OpenLoop and switch to ClosedLoop. Sometimes the motor needs 3-5 runs until it works. (in the attachment are the Basic and Advanced Settings from the EVM-GUI)

This seems like a reliablility problem. I assume your statement means that the motor is able to start spinning in open loop until it reaches the Open to Closed loop threshold where it tries to hand off to closed loop. However, the hand off is unsuccessful. Is this correct?

Can you tell me what faults you see when it fails to start up correctly? This can be done on the display tab on the GUI; allow for the fault to occur, then manually refresh to take a look at the fault (these faults are clear on read). However, these reliability concerns can usually be remedied by gradually increasing the open to closed loop threshold. Try this first.

1. What parameters should I change to drive as fast as possible in closed loop?

Are you asking how do to make the open loop operation as fast as possible? This is a tradeoff compared reliability which means faster start up is usually more likely to trigger faults. The DRV10983 Tuning Guide can give you more information but I'll point out a few things for you to try to start.

I notice you have Initial Position Detect (IPD) enabled, usually this can save some start up time and enter closed loop faster but I see the align time is at 1.3s. Set it to a minimum if IPD is enabled, check out the IPD section in the tuning guide for more information. Also, increasing acceleration coefficients (say 76 Hz/s instead of 38 Hz/s) might decrease time but trigger more faults. Check out the Handoff Threshold Optimization and AlignTime and Accelerate sections in the Tuning guide.

If you are asking how to make the speed go as fast as possible in closed loop, you'll need to make your speed command in closed loop = 100%. The method to do this depends if you are using PWM, I2C, or an analog voltage to control the speed. Consult the DRV10983 Speed Control section in the datasheet for more information.

1. The second problem is to detect the end stop of the actuator. The Ti-driver turns off automatically when the Motor can't be driven anymore, but that takes to much time. There is the risk that during this time the  peak torque could destroy the transmission of the actuator. The Motor is driven at 500 rpm or 829 rpm. there a possibility to detect the end stop detection faster, perhaps with an external circuit and the FG pin?

When you say: "TI-driver turns off automatically when the Motor can't be driven anymore, but that takes to much time." I assume the actuator physically hits the end stop, the DRV10983 drives for a little bit, but then throws a fault which stops driving the motor. Which fault is this? If you see Current Limit, the lock detection current threshold can be lowered for faster detection. If you see BEMF abnormal, the Abnormal Kt Lock Detect Threshold could be tightened.

Hope this helps,

-Cole