motordriver.cpp

00001 /*motor driver libary modified from the following libary,
00002 *
00003 * mbed simple H-bridge motor controller
00004 * Copyright (c) 2007-2010, sford
00005 *
00006 * by Christopher Hasler.
00007 *
00008 * from sford's libary,
00009 *
00010 * Permission is hereby granted, free of charge, to any person obtaining a copy
00011 * of this software and associated documentation files (the "Software"), to deal
00012 * in the Software without restriction, including without limitation the rights
00013 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00014 * copies of the Software, and to permit persons to whom the Software is
00015 * furnished to do so, subject to the following conditions:
00016 *
00017 * The above copyright notice and this permission notice shall be included in
00018 * all copies or substantial portions of the Software.
00019 *
00020 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00021 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00022 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00023 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00024 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00025 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00026 * THE SOFTWARE.
00027 */
00028 
00029 #include "motordriver.h"
00030 
00031 #include "mbed.h"
00032 
00033 Motor::Motor(PinName pwm, PinName fwd, PinName rev, int brakeable):
00034         _pwm(pwm), _fwd(fwd), _rev(rev) {
00035 
00036     // Set initial condition of PWM
00037     _pwm.period(0.001);
00038     _pwm = 0;
00039 
00040     // Initial condition of output enables
00041     _fwd = 0;
00042     _rev = 0;
00043 
00044     //set if the motor dirver is capable of braking. (addition)
00045     Brakeable= brakeable;
00046     sign = 0;//i.e nothing.
00047 }
00048 
00049 void Motor::setPwmFreq(float sec) {
00050     _pwm.period(sec);
00051 }
00052 
00053 float Motor::speed(float speed) {
00054     float temp = 0;
00055     if (sign == 0) {
00056         _fwd = (speed > 0.0);
00057         _rev = (speed < 0.0);
00058         temp = abs(speed);
00059         _pwm = temp;
00060     } else if (sign == 1) {
00061         if (speed < 0) {
00062             _fwd = (speed > 0.0);
00063             _rev = (speed < 0.0);
00064             _pwm = 0;
00065             temp = 0;
00066        } else {
00067             _fwd = (speed > 0.0);
00068             _rev = (speed < 0.0);
00069             temp = abs(speed);
00070             _pwm = temp;
00071         }
00072     } else if (sign == -1) {
00073         if (speed > 0) {
00074             _fwd = (speed > 0.0);
00075             _rev = (speed < 0.0);
00076             _pwm = 0;
00077             temp = 0;
00078         } else {
00079             _fwd = (speed > 0.0);
00080             _rev = (speed < 0.0);
00081             temp = abs(speed);
00082             _pwm = temp;
00083         }
00084     }
00085     if (speed > 0)
00086         sign = 1;
00087     else if (speed < 0) {
00088         sign = -1;
00089     } else if (speed == 0) {
00090         sign = 0;
00091     }
00092     return temp;
00093 }
00094 //  (additions)
00095 void Motor::coast(void) {
00096     _fwd = 0;
00097     _rev = 0;
00098     _pwm = 0;
00099     sign = 0;
00100 }
00101 
00102 float Motor::stop(float duty) {
00103     if (Brakeable == 1) {
00104         _fwd = 1;
00105         _rev = 1;
00106         _pwm = duty;
00107         sign = 0;
00108         return duty;
00109     } else
00110         Motor::coast();
00111         return -1;
00112 }
00113 
00114 float Motor::state(void) {
00115     if ((_fwd == _rev) && (_pwm > 0)) {
00116         return -2;//braking
00117     } else if (_pwm == 0) {
00118         return 2;//coasting
00119     } else if ((_fwd == 0) && (_rev == 1)) {
00120         return -(_pwm);//reversing
00121     }  else if ((_fwd == 1) && (_rev == 0)) {
00122         return _pwm;//fowards
00123     } else
00124         return -3;//error
00125 }
00126 
00127 /*
00128  test code, this demonstrates working motor drivers.
00129 
00130 Motor A(p22, p6, p5, 1); // pwm, fwd, rev, can break
00131 Motor B(p21, p7, p8, 1); // pwm, fwd, rev, can break
00132 int main() {
00133     for (float s=-1.0; s < 1.0 ; s += 0.01) {
00134        A.speed(s);
00135        B.speed(s);
00136        wait(0.02);
00137     }
00138     A.stop();
00139     B.stop();
00140     wait(1);
00141     A.coast();
00142     B.coast();
00143 }
00144 */