Hard real time control

[dineshlama]

I have a small question. Is it possible to use raspberry pi patched with xenomai to control the stepper motors/sevo motors in hard real time ? Are GPIO pins provide such timing constraint to control the motors, read the imu sensors etc? Or should i have to go for ethernet based control to fullfill hard real time control using rtnet+xenomai?

[joan]

Could you give an example of the sort of hard real-time control you are talking about?

For instance could you clarify how you are planning to control the servos and the steppers.

[dineshlama]

well, i am designing a mini weapon station controller which will have handgun, stepper motor, IMU sensor connected with raspberry pi. this mini weapon station is supposed to be able to fit in both ugv and uavs and controlled remotely. Here once the operator sets the target the weapon is to be focused on the target no matter how much the uav changes its position and oriantation at any speed, which is read by imu sensor and than it should be adjusting the motor position accordingly. Since if the motors loose its focus from the target when ugv changes its position/oriantation rapidly while maneuvering i'm trying to approach hard real time control method on the system so that no matter how much the uav/ugv moves the weapon will be always target the target given by the operator even after the recoil so that the system will be very accurate and precise.

For instance could you clarify how you are planning to control the servos and the steppers.
-> i'm planning to control the motors using drivers like this,https://www.pololu.com/product/2876 which is gpio based or thishttps://www.elmomc.com/product/gold-twitter/ or similar driver which is ethernet/ethercat based.
My doubt is can the gpio based driver provide the hard real time features to the system? considering that i use xenomai patched linux to control it.

[jbudd]

A real handgun, with real bullets? Under the control of a raspberry pi? Excellent idea.

Sounds educational, one way or another.

[dineshlama]

not a real handgun, its just a toy gun. just to test. i just wanted to develop a accurate, reliable, precise mini remote controlled weapons station so that the lives of solders would be saved in battlefield, so that with less effort and greater accuracy solders can deal with terrorists. Isn't it a good idea? why to loose a precise solders life in some terror encounter where robots can be used. cas each solder has their own family and if we can do something for them isn't it good? and raspberry pi is just for testing.