#### Mithrandir2008

##### New Member

Wall of text Warning!

Ok guys,

Just finished the control loop for the antenna tracking system. I'm uploading the .mdl file for those who are interested in looking through MATLAB.

I just have one last query I have to ask.

I need to know the parameters of the DC servo motor according to the design specs. The original motor is a 2-axis servo, but the control loop remains the same.

I need a torque of about 2 N-m and the power rating must be 300W running with a 24V DC supply.

The parameters that I need are the Torque Constant(Kt), Back emf Constant(Kf), Motor Resistance and Inductance(R and L).

The moment of Inertia I've calculated already and it comes to about 0.3375

The coefficient of viscous friction, I'm assuming to be about 0.2(which may be a bit largr though)

The model which I've implemented is COMPLETELY wrong in terms of motor parameters. I actually had to keep a 8000 amplifier(192KV!) to make it move fast enough

Oh and the speed of antenna movement must be about 80deg/sec. Motor speeds are generally much higher so I can use a gear box so no biggie there.

MODEL WORKING:

The model basically has two stages,

1) First, a manual input is given and the motor first moves/slews there.

2) Once stability is achived(error<0.5deg and oscillations<0.05deg), It has to switch to autotrack mode i.e, It has to align itself based on the signals recieved from the antenna.

I've already designed every block.

For those who need a breif idea on how auto tracking works,

A radar system has 4 points on it which recieve power(Imagine 4 points on a circle which form an X if joined). If the target is perfectly aligned with the bore(center), the points on the opposite ends will recieve the same power. So, the model is designed such that if the voltages recieved by the opposite ends are same, the target is reached.

I decided to simulate the antenna signals by simply applying the difference of the target and the posn of motor and splitting it into two.

All thats left now is to get the proper parameters to get the model working!

Any help/comments will be appreciated.

Thanks a lot.

Ok guys,

Just finished the control loop for the antenna tracking system. I'm uploading the .mdl file for those who are interested in looking through MATLAB.

I just have one last query I have to ask.

I need to know the parameters of the DC servo motor according to the design specs. The original motor is a 2-axis servo, but the control loop remains the same.

I need a torque of about 2 N-m and the power rating must be 300W running with a 24V DC supply.

The parameters that I need are the Torque Constant(Kt), Back emf Constant(Kf), Motor Resistance and Inductance(R and L).

The moment of Inertia I've calculated already and it comes to about 0.3375

The coefficient of viscous friction, I'm assuming to be about 0.2(which may be a bit largr though)

The model which I've implemented is COMPLETELY wrong in terms of motor parameters. I actually had to keep a 8000 amplifier(192KV!) to make it move fast enough

Oh and the speed of antenna movement must be about 80deg/sec. Motor speeds are generally much higher so I can use a gear box so no biggie there.

MODEL WORKING:

The model basically has two stages,

1) First, a manual input is given and the motor first moves/slews there.

2) Once stability is achived(error<0.5deg and oscillations<0.05deg), It has to switch to autotrack mode i.e, It has to align itself based on the signals recieved from the antenna.

I've already designed every block.

For those who need a breif idea on how auto tracking works,

A radar system has 4 points on it which recieve power(Imagine 4 points on a circle which form an X if joined). If the target is perfectly aligned with the bore(center), the points on the opposite ends will recieve the same power. So, the model is designed such that if the voltages recieved by the opposite ends are same, the target is reached.

I decided to simulate the antenna signals by simply applying the difference of the target and the posn of motor and splitting it into two.

All thats left now is to get the proper parameters to get the model working!

Any help/comments will be appreciated.

Thanks a lot.

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