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Servo Motor - jittery

Moderator: magicode

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Servo Motor - jittery

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ShadyMaple4

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Joined: Sun Sep 18, 2011 2:20 pm
Posts: 8

Servo Motor - jittery

Having a problem with 2 servos connected to ports 5 & 6. They run, but are very jittery...like shaky. Doesn't seem to be a motor problem, something with channel?

Fri Nov 18, 2011 2:03 pm

magicode

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Joined: Tue Sep 14, 2010 9:19 pm
Posts: 496

Re: Servo Motor - jittery

Can you give more details on the problem that you're having? How do you have the servos set up? What kind of load are they under? What code are you using to run them?

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Fri Nov 18, 2011 3:00 pm

ShadyMaple4

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Joined: Sun Sep 18, 2011 2:20 pm
Posts: 8

Re: Servo Motor - jittery

There is essentially no load - using as a conveyor system. Took off tracks and motors were still jittery. Changed motors, same thing. Servos are connected into ports 5 & 6 on the Cortex. Of course the competition is tomorrow.


	Code: #pragma config(Motor, port1, x, tmotorNormal, openLoop) #pragma config(Motor, port2, boom, tmotorNormal, openLoop) #pragma config(Motor, port3, ldrive, tmotorNormal, openLoop) #pragma config(Motor, port4, rdrive, tmotorNormal, openLoop) #pragma config(Motor, port5, armMotor, tmotorNormal, openLoop) #pragma config(Motor, port6, armMotor, tmotorNormal, openLoop) //!!Code automatically generated by 'ROBOTC' configuration wizard !!// task main () { while(1 == 1) { motor[port3] = vexRT[Ch3]; // drive motor[port2] = vexRT[Ch2]; // boom motor[port6] = vexRT[Ch6]; // intake motor[port4] = vexRT[Ch4]; // drive motor[port5] = vexRT[Ch5]; // intake if(vexRT[Btn5U] == 1) { motor[port5] = -127; } else if(vexRT[Btn5D] == 1) { motor[port5] = 127; } if(vexRT[Btn6U] == 1) { motor[port6] = -127; } else if(vexRT[Btn6D] == 1) { motor[port6] = 127; } } }

Fri Nov 18, 2011 3:09 pm

magicode

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Joined: Tue Sep 14, 2010 9:19 pm
Posts: 496

Re: Servo Motor - jittery

There is no vexRT[Ch5] or vexRT[Ch6] on the new vex joysticks. you have to access them via the vexRT[Btn5U] type commands like you did later in your code.

remove


	Code: motor[port6] = vexRT[Ch6]; // intake and motor[port5] = vexRT[Ch5]; // intake

from your code. Does that seem to solve your problem?

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Fri Nov 18, 2011 4:22 pm

ShadyMaple4

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Joined: Sun Sep 18, 2011 2:20 pm
Posts: 8

Re: Servo Motor - jittery

YES it solves the problem, however it doesn't stop running. We'd like to stop on release of button.

Fri Nov 18, 2011 5:00 pm

magicode

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Joined: Tue Sep 14, 2010 9:19 pm
Posts: 496

Re: Servo Motor - jittery

Well this is where you have to remember that "the robot does what you tell it to, not what you want it to". In your code, you tell the motors to got full forward if this button is pressed, full backwards if this other button is pressed, but you never tell it to stop if neither of the buttons are pressed.

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Fri Nov 18, 2011 6:42 pm

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