motor spinning erratically

Donut · Wed Jan 05, 2011 8:41 pm


	Code: #pragma config(Hubs, S1, HTMotor, HTMotor, none, none) #pragma config(Motor, motorA, claw, tmotorNormal, openLoop) #pragma config(Motor, mtr_S1_C1_1, leftDrive, tmotorNormal, openLoop) #pragma config(Motor, mtr_S1_C1_2, rightDrive, tmotorNormal, openLoop, reversed) #pragma config(Motor, mtr_S1_C2_1, arm, tmotorNormal, openLoop, reversed) #pragma config(Motor, mtr_S1_C2_2, bucket, tmotorNormal, openLoop) //!!Code automatically generated by 'ROBOTC' configuration wizard !!// #include "JoystickDriver.c" //Include file to "handle" the Bluetooth messages. void startup(){ motor[leftDrive]=0; motor[rightDrive]=0; return; } float absval(float vara){ float varb = vara((vara>0) + ((vara<0)-1)); return varb; } task main(){ startup(); /VARIABLES/ short dzone = 10; //universal controller deadzone (0-128) float turnscale = 0.0; //scalar used for turning /////////////DEFAULT CRAP//////////////////////// waitForStart(); //waits for start of teleop phase while(true){ getJoystickSettings(joystick); // has the FMS stopped the program if (joystick.StopPgm) { //nxtDisplayTextLine(2, "Disabled"); //re-add this for final wait1Msec(50); continue; // go back into top of while loop } //nxtDisplayTextLine(2, "Enabled"); //re-add this for final ///////////END DEFAULT CRAP//////////////////// /* put the rest of your code here / /NEW DRIVE CODE/ //get scale value /this takes the value of the x axis of the right thumbstick of controller 1, divides by the max value (128) to get a "unit joystick" reading, takes the absolute value of the number to turn it into a directionless scalar, and finally, subtracts the value from 1 so the value decreases as the x value gets bigger. we end up with a decimal scalar between 0 and 1 We dont care about deadzones here because we do a deadzone check later on anyway./ turnscale = 1-(absval(joystick.joy1_x2)/128); //nxtDisplayString(2,"%1.3f,%1.3f",turnscale,((joystick.joy1_y1/1.28)turnscale)); //for testing only. remove for final. //make motors move if((-dzone>joystick.joy1_y1)\|\|(joystick.joy1_y1>dzone)){ /none of these will ever be true at the same time as another so this is effectivly a case statement made from ifs this block checks the status of the x axis of the right thumbstick on controller 1/ //right if(joystick.joy1_x2>dzone){ motor[leftDrive]=(joystick.joy1_y1/1.27); motor[rightDrive]=(joystick.joy1_y1/1.27)turnscale; } //left if(-dzone>joystick.joy1_x2){ motor[leftDrive]=(joystick.joy1_y1/1.27)turnscale; motor[rightDrive]=(joystick.joy1_y1/1.27); } //straight, within deadzone if((-dzone<joystick.joy1_x2)\|\|(joystick.joy1_x2<dzone)){ motor[leftDrive]=(joystick.joy1_y1/1.27); motor[rightDrive]=(joystick.joy1_y1/1.27); } } else{ motor[leftDrive]=0; motor[rightDrive]=0; } //CLAW CODE if(joy1Btn(2)){ motor[claw]=50; } else if(joy1Btn(1)){ motor[claw]=-50; } else { motor[claw]=0; } /ARM AND BUCKET CODE/ //arm if((-10>joystick.joy2_y1)\|\|(joystick.joy2_y1>10)){ motor[arm]=(joystick.joy2_y1/1.27); } else motor[arm]=0; //bucket if(joy2Btn(5)){ motor[bucket]=-15; } else if(joy2Btn(6)){ motor[bucket]=15; } else{ motor[bucket]=0; } } }

the NEW DRIVE CODE section of the code is, as the name implies, new drive code that i wrote today to replace the old tank drive we had before. basically what it does is pass the value of joy1_y1 to both drive motors, and scales the power to either the left or right motor (depending on direction of joy1_x2) based on how far joy1_x2 is tilted. the issue is that the motor slows down and speeds up rapidly, making the turning system nearly useless.

this was my code before i started today:


	Code: #pragma config(Hubs, S1, HTMotor, HTMotor, none, none) #pragma config(Motor, motorA, claw, tmotorNormal, openLoop) #pragma config(Motor, mtr_S1_C1_1, leftDrive, tmotorNormal, openLoop) #pragma config(Motor, mtr_S1_C1_2, rightDrive, tmotorNormal, openLoop, reversed) //!!Code automatically generated by 'ROBOTC' configuration wizard !!// #include "JoystickDriver.c" //Include file to "handle" the Bluetooth messages. void startup(){ motor[leftDrive]=0; motor[rightDrive]=0; return; } task main(){ startup(); /VARIABLES/ short dzone = 10; //universal controller deadzone (0-128) short turnscale = 0; //scalar used for turning /////////////DEFAULT CRAP//////////////////////// waitForStart(); //waits for start of teleop phase while(true){ getJoystickSettings(joystick); // has the FMS stopped the program if (joystick.StopPgm) { //nxtDisplayTextLine(2, "Disabled"); //re-add this for final wait1Msec(50); continue; // go back into top of while loop } //nxtDisplayTextLine(2, "Enabled"); //re-add this for final ///////////END DEFAULT CRAP//////////////////// /* put the rest of your code here / /NEW DRIVE CODE/ //get scale value /this takes the value of the x axis of the right thumbstick of controller 1, divides by the max value (128) to get a "unit joystick" reading, takes the absolute value of the number to turn it into a directionless scalar, and finally, subtracts the value from 1 so the value decreases as the x value gets bigger. we end up with a decimal scalar between 0 and 1 We dont care about deadzones here because we do a deadzone check later on anyway./ turnscale = 1-(abs(joystick.joy1_x2)/128); //nxtDisplayString(2,"%1.3f,%1.3f",turnscale,((joystick.joy1_y1/1.28)turnscale)); //for testing only. remove for final. //make motors move if((-dzone>joystick.joy1_y1)\|\|(joystick.joy1_y1>dzone)){ /none of these will ever be true at the same time as another so this is effectivly a case statement made from ifs this block checks the status of the x axis of the right thumbstick on controller 1/ //right if(joystick.joy1_x2>dzone){ motor[leftDrive]=(joystick.joy1_y1/1.27); motor[rightDrive]=(joystick.joy1_y1/1.27)turnscale; } //left if(-dzone>joystick.joy1_x2){ motor[leftDrive]=(joystick.joy1_y1/1.27)turnscale; motor[rightDrive]=(joystick.joy1_y1/1.27); } //straight, within deadzone if((-dzone<joystick.joy1_x2)\|\|(joystick.joy1_x2<dzone)){ motor[leftDrive]=(joystick.joy1_y1/1.27); motor[rightDrive]=(joystick.joy1_y1/1.27); } } else{ motor[leftDrive]=0; motor[rightDrive]=0; } //CLAW CODE if(joy1Btn(2)){ motor[claw]=50; } else if(joy1Btn(1)){ motor[claw]=-50; } else { motor[claw]=0; } } }

i found out that shorts only store integers, and my scalar is a value between 0 and 1, so that was an issue. i switched turnscale to a float, and in the declaration statement changed the 0 to 0.000 so it would store 3 decimal places. its commented out in the code i posted, but i was having the nxt display the scale value. it was still displaying 0 or 1 (integer values), so i figured the only thing that could be wrong is the built in abs function. so i made my own absolute value function that i know supports decimal places. after i implemented that, the scale value was working perfectly, but the motors also started jerking around while they were spinning if i applied the turnscale variable to them.

im thinking the issue is something isnt updating in time for each cycle the code runs through. it might just be a hardware issue though. i dont know. basically what i want to know is, was i right about the absolute value function not supporting decimal places, and is this a hardware issue or a code issue?

i feel like this is a really incoherent post and that i left out a whole ton of information, so if you need to know anything else or need something cleared up, please let me know. :wink:

motor spinning erratically

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