trying to tie an r/c receiver output to pwm motor control
mikea
Posts: 283
ive done some digging and still dont understand how to write a code to proportionally relate the output of an r/c receiver to pwm motor. the goal is intercept signals and output them to the motor with the propeller.does anyone know of a tutorial, similar project, or thorough explanation they can point me to? -mike
Comments
I'm not sure if I've posted code to do this or not. I'll check and make sure to post a version of code that controls the motors based on the RC signal.
http://obex.parallax.com/objects/482/
http://obex.parallax.com/objects/331/
http://obex.parallax.com/objects/88/
Robert
robotworkshop, i live just west of kalamazoo, and have looked for a club or some people to meet with to learn some of this stuff and work on projects. i see you live in michigan and wondered if it was around kzoo if you know of any clubs/people to rub elbows with.
{{ ***************************************** * Mecanum * * Author: Rich Harman * * Copyright (c) Rich Harman * * See end of file for terms of use. * ***************************************** Begun Mar 15 2012 }} CON _clkmode = xtal1 + pll16x _xinfreq = 5_000_000 BasePinEnc = 0 'Pins 0 to 7 motors 1 to 4 quadrature input PWM1 = 8 'PWM input motor 1 PWM2 = 9 PWM3 = 10 PWM4 = 11 Motor1A = 23 Motor1B = 22 Motor2A = 21 Motor2B = 20 Motor3A = 19 Motor3B = 18 Motor4A = 17 Motor4B = 16 RC4 = 24 RC3 = 25 RC2 = 26 RC1 = 27 Kf = 100 Ks = 115 Ky = 100 Vscale = 40 null = 5 ramp = 1 MaxV = 255 Center = 1520 VAR long pulsewidth[4] long Strafe[2] long FWD[2] long Yaw[2] long FrontL long FrontR long RearL long RearR long Pos[8] 'Address of position buffer OBJ Encoder : "Quadrature Encoder" RX : "RX" pwm : "PWMx8" PUB Init dira := 00_0000_1111_1111_1111_1111_0000_0000 outa[Motor1A..Motor4B] := 11_1111 RX.start(@pins,@pulseWidth) pwm.start(PWM1, 00_1111, 20_000) 'Encoder.Start(BasePinEnc, 4, 4, @Pos) Main PUB Main repeat ReadRC 'ReadENC Calc Motors PUB ReadRC repeat until pulsewidth[0] =< 1920 or pulsewidth[0] >= 920 Strafe[1] := Strafe[0] FWD[1] := FWD[0] Yaw[1] := Yaw[0] Strafe[0] := -100 #> (pulsewidth[3] - Center) / 4 <# 100 FWD[0] := -100 #> (pulsewidth[2] - Center) / 4 <# 100 Yaw[0] := -100 #> (pulsewidth[1] - Center) / 4 <# 100 { if ||(Strafe[0] - Strafe[1]) > null Strafe[0] += ramp else Strafe[0] := Strafe[1] if ||(FWD[0] - FWD[1]) > null FWD[0] += ramp else FWD[0] := FWD[1] if ||(Yaw[0] - Yaw[1]) > null Yaw[0] += ramp else Yaw[0] := Yaw[1] } PUB ReadEnc ' repeat ' <read Pos[0] or Pos[1] here> 'Read each encoder's absolute position ' <variable> := Encoder.ReadDelta(0) 'Read 1st encoder's delta position (value since last read) PUB Calc | Vmax FrontL := ((Kf * FWD) + (Ks * Strafe) + (Ky * Yaw)) / Vscale Vmax := FrontL FrontR := ((Kf * FWD) - (Ks * Strafe) - (Ky * Yaw)) / Vscale if ||FrontR => ||Vmax Vmax := FrontR RearL := ((Kf * FWD) - (Ks * Strafe) + (Ky * Yaw)) / Vscale if ||RearL => ||Vmax Vmax := RearL RearR := ((Kf * FWD) + (Ks * Strafe) - (Ky * Yaw)) / Vscale if ||RearR => ||Vmax Vmax := RearR ||Vmax if Vmax => MaxV FrontR := (FrontR * 100) / ((Vmax * 100) / MaxV) FrontL := (FrontL * 100) / ((Vmax * 100) / MaxV) RearL := (RearL * 100) / ((Vmax * 100) / MaxV) RearR := (RearR * 100) / ((Vmax * 100) / MaxV) Pub Motors '// Set motor direction and power if FrontL == 0 outa[Motor1A .. Motor1B] := if FrontL < 0 outa[Motor1A..Motor1B] := if FrontL > 0 outa[Motor1A..Motor1B] := pwm.duty(PWM1, ||FrontL) if FrontR == 0 outa[Motor2A .. Motor2B] := if FrontR < 0 outa[Motor2A..Motor2B] := if FrontR > 0 outa[Motor2A..Motor2B] := pwm.duty(PWM2, ||FrontR) if RearL == 0 outa[Motor3A .. Motor3B] := if RearL < 0 outa[Motor3A..Motor3B] := if RearL > 0 outa[Motor3A..Motor3B] := pwm.duty(PWM3, ||RearL) if RearR == 0 outa[Motor4A .. Motor4B] := if RearR < 0 outa[Motor4A..Motor4B] := if RearR > 0 outa[Motor4A..Motor4B] := pwm.duty(PWM4, ||RearR)Jason Dorie has an object (I think modified from someone elses code) that monitors six channels with one cog. The down side to Jason's object is it needs to use the first six pins. This wasn't a problem with my breadboard version of the robot. My current plan is to use Nordic nRF24L01+ modules to control the robot so I wont be using RC gear at all with it.
Your robot has the power to drive those Mecanum wheels with authority without using encoders. The Rover 5 chassis I'm using, has a really hard time without the assistance of the encoders.
I hope you post more details about your robot some time. I'd really like to know what motors you're using. It looks amazing!
I added the code to my Mecanum robot thread.