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Basic ESC resets when thruster operate direction reverse


(chongman) #1

Dear all,

I am new user of Blue robotic’s equipments and I meet some problem on using basic ESC & T200 recently.

When I do testing with T200 thruster and basic ESC, I found that the ESC resets when it runs the following program with Arduino:

#include <Servo.h> byte servoPin = 9; Servo servo; void setup() { servo.attach(servoPin); servo.writeMicroseconds(1500); delay(1000); } void loop() { servo.writeMicroseconds(1900); delay(5000); servo.writeMicroseconds(1100); //ESC resets here! delay(5000); }

It seems that the ESC resets(green light flash once) when it made changing of the thruster direction. The input voltage of ESC is 12V and I am using both Arduino and Arduino MEGA(MCU powered by Macbook Pro USB power). The wring is followed the original documentation of basic ESC page. Did anyone meet this problem before and what can I try for the solution?

Thanks in advance!


(Rusty) #2

Hi Chongman,

Thanks for the post. I would guess that the 12V power supply being used cannot handle the current spike that will be caused when you reverse direction like that. The voltage may drop below a certain level when that happens and cause the ESC to reset. What type of power supply are you using?

-Rusty


(chongman) #3

Dear Rusty,
Thanks for your reply.
In our testing case, we used a kind of digital power supply like the following one (not extract this):
http://www.wavecom.com.au/03_product_images/683/PS-3005D-3C.jpg

We set the voltage output is 12v and the maximum current output is 10A.

I also suspected that happen because of huge current spike because we tried to reverse the thruster direction in lower speed case (I mean, writing PWM signal from 1600 to 1400). It works but the thruster is not powerful enough for our ROV.

So, do you think it’s the problem of power supply? What kind of power supply do you suggest? Or there’s other solution for us to overcome this problem.

Thanks again for your help!


(Rusty) #4

Chongman,

Okay. The 12V, 10A power supply is definitely not enough to handle this current spike. The T200 can actually draw about 15 amps at 12V, so this supply is not enough for normal operation either. It will probably automatically drop the voltage so that the thruster does not reach full power.

I would recommend a supply that can handle at least 20 amps, preferably more. You can also consider using a lithium polymer battery, which should be able to supply fairly high current.

-Rusty


(chongman) #5

Dear Rusty,
Thanks for your reply, I will try to increase the maximum current of the power supply into 30A and let’s see if it works.

Many thanks for your help!

Chongman


(chongman) #6

Dear Rusty,
Just now I tried to increase the maximum current output of our power supply into 20A and it puts me into the same situation. So that I shoot the following video and hope it helps for explaining the situation I encounter.

And I found that MCU(Arduino MEGA) is not work normally until I press reset button of Arduino MEGA after the thruster direction reversed.

Thanks in advance for your helping!


(Rusty) #7

Hi Chongman,

Okay, are there any other points in your wiring that could be causing a voltage drop? This could be thin power wires to the ESC or a poor connection to the ESC or power supply.

I would also recommend trying higher than 20A if possible. Since you’re reversing instantaneously, the instantaneous current draw could be very high. This might be improved when run in water because the water resistance will help slow down the propeller.

The Arduino needs to be reset after the ESC resets so that the initialization signal (1500 µs) is sent again.

-Rusty


(chongman) #8

Dear Rusty,
Thanks for your replies. Just now I used a 12V DC car battery and it works finally. In our lab we just have a 1-30V/DC, 20A power supply so that 20A is our maximum current output we can try.

But I wonder if the thruster and ESC can work under the low maximum current condition (let’s say, 20A). Since the maximum current limitation of ranger class of MATE competition is 25A and I wonder is that possible to operate the thruster well under this case. Or there’s some solution we can do (like software or electrical approach) for making this ESC and thruster can able to work well under such a insufficient maximum current output situation?

Many thanks for your help!


(Richard) #9

Why do you have to instantaneously reverse direction? Why not put a 1500 usec brief pause in there?


(chongman) #10

Dear Richard,
Yes I have tried something like following:


servo.writeMicroseconds(1900);
delay(5000);
servo.writeMicroseconds(1500);
delay(5000);
servo.writeMicroseconds(1100); //ESC resets here!
delay(5000);

But same problem happened, and I tried to give them some “buffer” like following:


void loop() {
int i = 0;
for(i=1100;i&lt;=1900;i+=50){
servo.writeMicroseconds(i); 
delay(20); 
} 
servo.writeMicroseconds(1900);
delay(2000);
for(i=1900;i&gt;=1100;i-=20){
servo.writeMicroseconds(i);
delay(20);
}
servo.writeMicroseconds(1100);
delay(2000);
}

And the thruster can able to reverse the direction with full power. But it’s hard for both programmer and ROV driver.
(sorry for the code formatting)


(Richard) #11

Please give me a link to the rules for Mate Ranger competition . Also, is the reset occurring with the thruster underwater? To go from stopped to 1900 in the water should not cause an ESC reset unless your power supply is unregulated and has very high internal resistance. What are the specs for your power supply? Won’t you be using a battery for the competition?


(chongman) #12

Dear Richard,
Thanks for your reply. I just test the thruster in air, I will try to test it in the water tomorrow.

The competition manual of MATE ranger class: http://www.marinetech.org/files/marine/files/ROV%20Competition/2016%20competition/Missions/Updated%20files/RANGER%20MANUAL_FINAL_cover_12_3_2015.pdf

For the competition, we must use the power supply they provided but we do not know which kind of supply that they really provided. It may be different year by year. So I just want to avoid this problem and figure out what happened in this situation.

I will give you the details of power supply once I come back to lab.

Thanks for your helping!


(chongman) #13

Dear Richard,
This is our power supply’s information
http://www.manson.com.hk/products/detail/159

Model: HCS-3402-USB