Ren Buggy
A program that allows control of the RenBuggy by steering with a servo controlled wheel.
Revision 0:c95c77611812, committed 2016-03-11
- Comitter:
- RenBuggy
- Date:
- Fri Mar 11 10:37:50 2016 +0000
- Commit message:
- version 1
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ServoDrive.cpp Fri Mar 11 10:37:50 2016 +0000
@@ -0,0 +1,110 @@
+/*********************************************************
+*ServoDrive.cpp *
+*Author: Elijah Orr *
+* *
+*A library of functions that can be used to control the *
+*RenBuggy via a servo motor. *
+*********************************************************/
+
+#ifndef SERVODRIVE_C
+#define SERVODRIVE_C
+
+#include "mbed.h"
+#include "ServoDrive.h"
+
+
+/* A pin is configured as PwmOut to output the PWM signal that will
+control the servo. Two pins are configured as DigitalOut to switch
+the drive motors on/off. Information about classes used here can be
+found in the mbed library. */
+PwmOut servo(servoPin);
+DigitalOut Lmotor(LeftMotorPin);
+DigitalOut Rmotor(RightMotorPin);
+
+/* functions to start and stop the drive motors simply set the DigitalOut
+pins to 1 or 0 to switch the motors on/off */
+
+/****************************************************************
+* Function: go() *
+* *
+* Enables the two drive motors of the RenBuggy *
+* *
+* Inputs: none *
+* *
+* Returns: none *
+****************************************************************/
+extern void go()
+{
+ Lmotor = Rmotor = 1;
+}
+
+/****************************************************************
+* Function: stop() *
+* *
+* Disables the two drive motors of the RenBuggy *
+* *
+* Inputs: none *
+* *
+* Returns: none *
+****************************************************************/
+extern void stop()
+{
+ Lmotor = Rmotor = 0;
+}
+
+/* a function is set up to configure the PWM output so that it will have the
+correct properties to operate the servo. */
+
+/****************************************************************
+* Function: configurePWM() *
+* *
+* Configures a PWM signal for controlling the servo *
+* *
+* Inputs: Period is the period of the signal in microseconds *
+* and Pulsewidth is the pulsewidth of the signal in microseconds*
+* *
+* Returns: none *
+****************************************************************/
+extern void configurePWM(int Period, int Pulsewidth)
+{
+ /* classes that set the properties of the PWM signal are passed the variables
+ Period and Pulsewidth to set the frequency and duty cycle of the signal. */
+ servo.period_us(Period);
+ servo.pulsewidth_us(Pulsewidth);
+}
+
+/* to make the main function easy to write, setDirection will allow a value in
+degrees to be passed to it, and then do any necessary conversions. angle must be
+a float as the conversion involves non integer values. */
+
+/****************************************************************
+* Function: setDirection() *
+* *
+* Sets the direction in which the steering servo is pointing *
+* *
+* Inputs: A floating point value representing the angle of the *
+* servo in degrees *
+* *
+* Returns: none *
+****************************************************************/
+extern void setDirection(float angle)
+{
+ /* it is possible to pass numbers outside the operational range of the servo
+ to setDirection, to resolve this there are two checks here. If angle is outside
+ the boundaries it will be set to either the maximum or minimum value. */
+ if(angle < 0)
+ {
+ angle = 0;
+ }
+ if(angle > 90)
+ {
+ angle = 90;
+ }
+ /* to properly control the servo, the pulsewidth must be between 1000 and 2000
+ micro seconds, so a simple conversion is used to translate the angle into a value
+ within these bounds. The new value is stored in the variable pulse. */
+ int pulse = 1000 + ((angle/90)*1000);
+ servo.pulsewidth_us(pulse);
+}
+
+#endif //SERVODRIVE_C
\ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ServoDrive.h Fri Mar 11 10:37:50 2016 +0000 @@ -0,0 +1,33 @@ +/********************************************************* +*ServoDrive.h * +*Author: Elijah Orr * +* * +*A library of functions that can be used to control the * +*RenBuggy via a servo motor. * +*********************************************************/ + +/* include guards are used to prevent problems caused by +multiple definitions */ +#ifndef SERVODRIVE_H +#define SERVODRIVE_H + +/* mbed.h must be included in this file also */ +#include "mbed.h" + +/* #define is used to set the pins that will be used to control the motors. +Using this method means that selecting which pins are used requires only +changing values here, rather than in every function that contains them. */ +#define servoPin p10 +#define LeftMotorPin p5 +#define RightMotorPin p6 + +/* function declarations go here */ +extern void go(); +extern void stop(); +/* setDirection takes a variable of type float (non integer) that will represent an angle in +degrees. */ +extern void setDirection(float); +/* configurePWM expects two variables of type int */ +extern void configurePWM(int, int); + +#endif //SERVODRIVE_H \ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Fri Mar 11 10:37:50 2016 +0000
@@ -0,0 +1,60 @@
+/*********************************************************
+*RenBuggyServoCtrl *
+*Author: Elijah Orr *
+* *
+*This program demonstates use of a library of functions *
+*(ServoDrive) to control the movement of the RenBuggy. *
+* *
+*********************************************************/
+
+/* include the libraries in use in this program. ServoDrive is a library that can
+be used to control a steering servo and two drive motors. */
+#include "mbed.h"
+#include "ServoDrive.h"
+
+/* open the main function */
+int main()
+{
+ /* instead of using wait() to make delays in the program, for loops will be used
+ as the wait function caused some buggy behaviour. The for loops will require a
+ variable so it is declared at the top of the main, this is where all variables
+ used in the main function should be declared. */
+ int i;
+
+ /* the first function to be called from ServoDrive.h is used to configure the PWM
+ output that controls the servo. Both parameters are values in micro seconds that
+ correspond to the period (20000) and pulsewidth (1500) of the PWM signal. 1500
+ corresponds the the servo in centre postion after the line executes. */
+ configurePWM(20000, 1500);
+
+ /* function to start the drive motors going is called */
+ go();
+
+ /* the first delay goes here to make the buggy move forward for a time before
+ turning. The for loop will initialise the variable i to be 0, and enter the
+ program into a loop that will repeatedly check that i < 25000000 and increment
+ i as long as the statement is true. When i = 25000000 the program will exit the
+ loop and move on to the next line. */
+ for(i=0;i<25000000;i++){}
+
+ /* the function to set the direction the servo controlled wheel is facing is
+ called. It takes a single parameter that can be any number between 0 and 90,
+ which represents a value in degrees where 45 points the wheel directly forward. */
+ setDirection(70);
+ for(i=0;i<25000000;i++){}
+
+ setDirection(10);
+ for(i=0;i<25000000;i++){}
+
+ setDirection(90);
+ for(i=0;i<25000000;i++){}
+
+ setDirection(30);
+ for(i=0;i<25000000;i++){}
+
+ /* function to stop the drive motors is called */
+ stop();
+
+ return 0;
+}
+
\ No newline at end of file
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Fri Mar 11 10:37:50 2016 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/252557024ec3 \ No newline at end of file