Warwick Racing
PID library (not mine)
Dependents: ElecPneuShifter_4 ipod
PID.cpp@0:9fe5d80c3c5e, 2010-11-28 (annotated)
- Committer:
- WarwickRacing
- Date:
- Sun Nov 28 14:20:07 2010 +0000
- Revision:
- 0:9fe5d80c3c5e
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| WarwickRacing | 0:9fe5d80c3c5e | 1 | /** |
| WarwickRacing | 0:9fe5d80c3c5e | 2 | * @author Aaron Berk |
| WarwickRacing | 0:9fe5d80c3c5e | 3 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 4 | * @section LICENSE |
| WarwickRacing | 0:9fe5d80c3c5e | 5 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 6 | * Copyright (c) 2010 ARM Limited |
| WarwickRacing | 0:9fe5d80c3c5e | 7 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 8 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| WarwickRacing | 0:9fe5d80c3c5e | 9 | * of this software and associated documentation files (the "Software"), to deal |
| WarwickRacing | 0:9fe5d80c3c5e | 10 | * in the Software without restriction, including without limitation the rights |
| WarwickRacing | 0:9fe5d80c3c5e | 11 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| WarwickRacing | 0:9fe5d80c3c5e | 12 | * copies of the Software, and to permit persons to whom the Software is |
| WarwickRacing | 0:9fe5d80c3c5e | 13 | * furnished to do so, subject to the following conditions: |
| WarwickRacing | 0:9fe5d80c3c5e | 14 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 15 | * The above copyright notice and this permission notice shall be included in |
| WarwickRacing | 0:9fe5d80c3c5e | 16 | * all copies or substantial portions of the Software. |
| WarwickRacing | 0:9fe5d80c3c5e | 17 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| WarwickRacing | 0:9fe5d80c3c5e | 19 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| WarwickRacing | 0:9fe5d80c3c5e | 20 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| WarwickRacing | 0:9fe5d80c3c5e | 21 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| WarwickRacing | 0:9fe5d80c3c5e | 22 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| WarwickRacing | 0:9fe5d80c3c5e | 23 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| WarwickRacing | 0:9fe5d80c3c5e | 24 | * THE SOFTWARE. |
| WarwickRacing | 0:9fe5d80c3c5e | 25 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 26 | * @section DESCRIPTION |
| WarwickRacing | 0:9fe5d80c3c5e | 27 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 28 | * A PID controller is a widely used feedback controller commonly found in |
| WarwickRacing | 0:9fe5d80c3c5e | 29 | * industry. |
| WarwickRacing | 0:9fe5d80c3c5e | 30 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 31 | * This library is a port of Brett Beauregard's Arduino PID library: |
| WarwickRacing | 0:9fe5d80c3c5e | 32 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 33 | * http://www.arduino.cc/playground/Code/PIDLibrary |
| WarwickRacing | 0:9fe5d80c3c5e | 34 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 35 | * The wikipedia article on PID controllers is a good place to start on |
| WarwickRacing | 0:9fe5d80c3c5e | 36 | * understanding how they work: |
| WarwickRacing | 0:9fe5d80c3c5e | 37 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 38 | * http://en.wikipedia.org/wiki/PID_controller |
| WarwickRacing | 0:9fe5d80c3c5e | 39 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 40 | * For a clear and elegant explanation of how to implement and tune a |
| WarwickRacing | 0:9fe5d80c3c5e | 41 | * controller, the controlguru website by Douglas J. Cooper (who also happened |
| WarwickRacing | 0:9fe5d80c3c5e | 42 | * to be Brett's controls professor) is an excellent reference: |
| WarwickRacing | 0:9fe5d80c3c5e | 43 | * |
| WarwickRacing | 0:9fe5d80c3c5e | 44 | * http://www.controlguru.com/ |
| WarwickRacing | 0:9fe5d80c3c5e | 45 | */ |
| WarwickRacing | 0:9fe5d80c3c5e | 46 | |
| WarwickRacing | 0:9fe5d80c3c5e | 47 | /** |
| WarwickRacing | 0:9fe5d80c3c5e | 48 | * Includes |
| WarwickRacing | 0:9fe5d80c3c5e | 49 | */ |
| WarwickRacing | 0:9fe5d80c3c5e | 50 | #include "PID.h" |
| WarwickRacing | 0:9fe5d80c3c5e | 51 | |
| WarwickRacing | 0:9fe5d80c3c5e | 52 | PID::PID(float Kc, float tauI, float tauD, float interval) { |
| WarwickRacing | 0:9fe5d80c3c5e | 53 | |
| WarwickRacing | 0:9fe5d80c3c5e | 54 | usingFeedForward = false; |
| WarwickRacing | 0:9fe5d80c3c5e | 55 | inAuto = false; |
| WarwickRacing | 0:9fe5d80c3c5e | 56 | |
| WarwickRacing | 0:9fe5d80c3c5e | 57 | //Default the limits to the full range of I/O: 3.3V |
| WarwickRacing | 0:9fe5d80c3c5e | 58 | //Make sure to set these to more appropriate limits for |
| WarwickRacing | 0:9fe5d80c3c5e | 59 | //your application. |
| WarwickRacing | 0:9fe5d80c3c5e | 60 | setInputLimits(0.0, 3.3); |
| WarwickRacing | 0:9fe5d80c3c5e | 61 | setOutputLimits(0.0, 3.3); |
| WarwickRacing | 0:9fe5d80c3c5e | 62 | |
| WarwickRacing | 0:9fe5d80c3c5e | 63 | tSample_ = interval; |
| WarwickRacing | 0:9fe5d80c3c5e | 64 | |
| WarwickRacing | 0:9fe5d80c3c5e | 65 | setTunings(Kc, tauI, tauD); |
| WarwickRacing | 0:9fe5d80c3c5e | 66 | |
| WarwickRacing | 0:9fe5d80c3c5e | 67 | setPoint_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 68 | processVariable_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 69 | prevProcessVariable_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 70 | controllerOutput_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 71 | prevControllerOutput_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 72 | |
| WarwickRacing | 0:9fe5d80c3c5e | 73 | accError_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 74 | bias_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 75 | |
| WarwickRacing | 0:9fe5d80c3c5e | 76 | realOutput_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 77 | |
| WarwickRacing | 0:9fe5d80c3c5e | 78 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 79 | |
| WarwickRacing | 0:9fe5d80c3c5e | 80 | void PID::setInputLimits(float inMin, float inMax) { |
| WarwickRacing | 0:9fe5d80c3c5e | 81 | |
| WarwickRacing | 0:9fe5d80c3c5e | 82 | //Make sure we haven't been given impossible values. |
| WarwickRacing | 0:9fe5d80c3c5e | 83 | if (inMin >= inMax) { |
| WarwickRacing | 0:9fe5d80c3c5e | 84 | return; |
| WarwickRacing | 0:9fe5d80c3c5e | 85 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 86 | |
| WarwickRacing | 0:9fe5d80c3c5e | 87 | //Rescale the working variables to reflect the changes. |
| WarwickRacing | 0:9fe5d80c3c5e | 88 | prevProcessVariable_ *= (inMax - inMin) / inSpan_; |
| WarwickRacing | 0:9fe5d80c3c5e | 89 | accError_ *= (inMax - inMin) / inSpan_; |
| WarwickRacing | 0:9fe5d80c3c5e | 90 | |
| WarwickRacing | 0:9fe5d80c3c5e | 91 | //Make sure the working variables are within the new limits. |
| WarwickRacing | 0:9fe5d80c3c5e | 92 | if (prevProcessVariable_ > 1) { |
| WarwickRacing | 0:9fe5d80c3c5e | 93 | prevProcessVariable_ = 1; |
| WarwickRacing | 0:9fe5d80c3c5e | 94 | } else if (prevProcessVariable_ < 0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 95 | prevProcessVariable_ = 0; |
| WarwickRacing | 0:9fe5d80c3c5e | 96 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 97 | |
| WarwickRacing | 0:9fe5d80c3c5e | 98 | inMin_ = inMin; |
| WarwickRacing | 0:9fe5d80c3c5e | 99 | inMax_ = inMax; |
| WarwickRacing | 0:9fe5d80c3c5e | 100 | inSpan_ = inMax - inMin; |
| WarwickRacing | 0:9fe5d80c3c5e | 101 | |
| WarwickRacing | 0:9fe5d80c3c5e | 102 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 103 | |
| WarwickRacing | 0:9fe5d80c3c5e | 104 | void PID::setOutputLimits(float outMin, float outMax) { |
| WarwickRacing | 0:9fe5d80c3c5e | 105 | |
| WarwickRacing | 0:9fe5d80c3c5e | 106 | //Make sure we haven't been given impossible values. |
| WarwickRacing | 0:9fe5d80c3c5e | 107 | if (outMin >= outMax) { |
| WarwickRacing | 0:9fe5d80c3c5e | 108 | return; |
| WarwickRacing | 0:9fe5d80c3c5e | 109 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 110 | |
| WarwickRacing | 0:9fe5d80c3c5e | 111 | //Rescale the working variables to reflect the changes. |
| WarwickRacing | 0:9fe5d80c3c5e | 112 | prevControllerOutput_ *= (outMax - outMin) / outSpan_; |
| WarwickRacing | 0:9fe5d80c3c5e | 113 | |
| WarwickRacing | 0:9fe5d80c3c5e | 114 | //Make sure the working variables are within the new limits. |
| WarwickRacing | 0:9fe5d80c3c5e | 115 | if (prevControllerOutput_ > 1) { |
| WarwickRacing | 0:9fe5d80c3c5e | 116 | prevControllerOutput_ = 1; |
| WarwickRacing | 0:9fe5d80c3c5e | 117 | } else if (prevControllerOutput_ < 0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 118 | prevControllerOutput_ = 0; |
| WarwickRacing | 0:9fe5d80c3c5e | 119 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 120 | |
| WarwickRacing | 0:9fe5d80c3c5e | 121 | outMin_ = outMin; |
| WarwickRacing | 0:9fe5d80c3c5e | 122 | outMax_ = outMax; |
| WarwickRacing | 0:9fe5d80c3c5e | 123 | outSpan_ = outMax - outMin; |
| WarwickRacing | 0:9fe5d80c3c5e | 124 | |
| WarwickRacing | 0:9fe5d80c3c5e | 125 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 126 | |
| WarwickRacing | 0:9fe5d80c3c5e | 127 | void PID::setTunings(float Kc, float tauI, float tauD) { |
| WarwickRacing | 0:9fe5d80c3c5e | 128 | |
| WarwickRacing | 0:9fe5d80c3c5e | 129 | //Verify that the tunings make sense. |
| WarwickRacing | 0:9fe5d80c3c5e | 130 | if (Kc == 0.0 || tauI < 0.0 || tauD < 0.0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 131 | return; |
| WarwickRacing | 0:9fe5d80c3c5e | 132 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 133 | |
| WarwickRacing | 0:9fe5d80c3c5e | 134 | //Store raw values to hand back to user on request. |
| WarwickRacing | 0:9fe5d80c3c5e | 135 | pParam_ = Kc; |
| WarwickRacing | 0:9fe5d80c3c5e | 136 | iParam_ = tauI; |
| WarwickRacing | 0:9fe5d80c3c5e | 137 | dParam_ = tauD; |
| WarwickRacing | 0:9fe5d80c3c5e | 138 | |
| WarwickRacing | 0:9fe5d80c3c5e | 139 | float tempTauR; |
| WarwickRacing | 0:9fe5d80c3c5e | 140 | |
| WarwickRacing | 0:9fe5d80c3c5e | 141 | if (tauI == 0.0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 142 | tempTauR = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 143 | } else { |
| WarwickRacing | 0:9fe5d80c3c5e | 144 | tempTauR = (1.0 / tauI) * tSample_; |
| WarwickRacing | 0:9fe5d80c3c5e | 145 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 146 | |
| WarwickRacing | 0:9fe5d80c3c5e | 147 | //For "bumpless transfer" we need to rescale the accumulated error. |
| WarwickRacing | 0:9fe5d80c3c5e | 148 | if (inAuto) { |
| WarwickRacing | 0:9fe5d80c3c5e | 149 | if (tempTauR == 0.0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 150 | accError_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 151 | } else { |
| WarwickRacing | 0:9fe5d80c3c5e | 152 | accError_ *= (Kc_ * tauR_) / (Kc * tempTauR); |
| WarwickRacing | 0:9fe5d80c3c5e | 153 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 154 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 155 | |
| WarwickRacing | 0:9fe5d80c3c5e | 156 | Kc_ = Kc; |
| WarwickRacing | 0:9fe5d80c3c5e | 157 | tauR_ = tempTauR; |
| WarwickRacing | 0:9fe5d80c3c5e | 158 | tauD_ = tauD / tSample_; |
| WarwickRacing | 0:9fe5d80c3c5e | 159 | |
| WarwickRacing | 0:9fe5d80c3c5e | 160 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 161 | |
| WarwickRacing | 0:9fe5d80c3c5e | 162 | void PID::reset(void) { |
| WarwickRacing | 0:9fe5d80c3c5e | 163 | |
| WarwickRacing | 0:9fe5d80c3c5e | 164 | float scaledBias = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 165 | |
| WarwickRacing | 0:9fe5d80c3c5e | 166 | if (usingFeedForward) { |
| WarwickRacing | 0:9fe5d80c3c5e | 167 | scaledBias = (bias_ - outMin_) / outSpan_; |
| WarwickRacing | 0:9fe5d80c3c5e | 168 | } else { |
| WarwickRacing | 0:9fe5d80c3c5e | 169 | scaledBias = (realOutput_ - outMin_) / outSpan_; |
| WarwickRacing | 0:9fe5d80c3c5e | 170 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 171 | |
| WarwickRacing | 0:9fe5d80c3c5e | 172 | prevControllerOutput_ = scaledBias; |
| WarwickRacing | 0:9fe5d80c3c5e | 173 | prevProcessVariable_ = (processVariable_ - inMin_) / inSpan_; |
| WarwickRacing | 0:9fe5d80c3c5e | 174 | |
| WarwickRacing | 0:9fe5d80c3c5e | 175 | //Clear any error in the integral. |
| WarwickRacing | 0:9fe5d80c3c5e | 176 | accError_ = 0; |
| WarwickRacing | 0:9fe5d80c3c5e | 177 | |
| WarwickRacing | 0:9fe5d80c3c5e | 178 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 179 | |
| WarwickRacing | 0:9fe5d80c3c5e | 180 | void PID::setMode(int mode) { |
| WarwickRacing | 0:9fe5d80c3c5e | 181 | |
| WarwickRacing | 0:9fe5d80c3c5e | 182 | //We were in manual, and we just got set to auto. |
| WarwickRacing | 0:9fe5d80c3c5e | 183 | //Reset the controller internals. |
| WarwickRacing | 0:9fe5d80c3c5e | 184 | if (mode != 0 && !inAuto) { |
| WarwickRacing | 0:9fe5d80c3c5e | 185 | reset(); |
| WarwickRacing | 0:9fe5d80c3c5e | 186 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 187 | |
| WarwickRacing | 0:9fe5d80c3c5e | 188 | inAuto = (mode != 0); |
| WarwickRacing | 0:9fe5d80c3c5e | 189 | |
| WarwickRacing | 0:9fe5d80c3c5e | 190 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 191 | |
| WarwickRacing | 0:9fe5d80c3c5e | 192 | void PID::setInterval(float interval) { |
| WarwickRacing | 0:9fe5d80c3c5e | 193 | |
| WarwickRacing | 0:9fe5d80c3c5e | 194 | if (interval > 0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 195 | //Convert the time-based tunings to reflect this change. |
| WarwickRacing | 0:9fe5d80c3c5e | 196 | tauR_ *= (interval / tSample_); |
| WarwickRacing | 0:9fe5d80c3c5e | 197 | accError_ *= (tSample_ / interval); |
| WarwickRacing | 0:9fe5d80c3c5e | 198 | tauD_ *= (interval / tSample_); |
| WarwickRacing | 0:9fe5d80c3c5e | 199 | tSample_ = interval; |
| WarwickRacing | 0:9fe5d80c3c5e | 200 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 201 | |
| WarwickRacing | 0:9fe5d80c3c5e | 202 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 203 | |
| WarwickRacing | 0:9fe5d80c3c5e | 204 | void PID::setSetPoint(float sp) { |
| WarwickRacing | 0:9fe5d80c3c5e | 205 | |
| WarwickRacing | 0:9fe5d80c3c5e | 206 | setPoint_ = sp; |
| WarwickRacing | 0:9fe5d80c3c5e | 207 | |
| WarwickRacing | 0:9fe5d80c3c5e | 208 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 209 | |
| WarwickRacing | 0:9fe5d80c3c5e | 210 | void PID::setProcessValue(float pv) { |
| WarwickRacing | 0:9fe5d80c3c5e | 211 | |
| WarwickRacing | 0:9fe5d80c3c5e | 212 | processVariable_ = pv; |
| WarwickRacing | 0:9fe5d80c3c5e | 213 | |
| WarwickRacing | 0:9fe5d80c3c5e | 214 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 215 | |
| WarwickRacing | 0:9fe5d80c3c5e | 216 | void PID::setBias(float bias){ |
| WarwickRacing | 0:9fe5d80c3c5e | 217 | |
| WarwickRacing | 0:9fe5d80c3c5e | 218 | bias_ = bias; |
| WarwickRacing | 0:9fe5d80c3c5e | 219 | usingFeedForward = 1; |
| WarwickRacing | 0:9fe5d80c3c5e | 220 | |
| WarwickRacing | 0:9fe5d80c3c5e | 221 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 222 | |
| WarwickRacing | 0:9fe5d80c3c5e | 223 | float PID::compute() { |
| WarwickRacing | 0:9fe5d80c3c5e | 224 | |
| WarwickRacing | 0:9fe5d80c3c5e | 225 | //Pull in the input and setpoint, and scale them into percent span. |
| WarwickRacing | 0:9fe5d80c3c5e | 226 | float scaledPV = (processVariable_ - inMin_) / inSpan_; |
| WarwickRacing | 0:9fe5d80c3c5e | 227 | |
| WarwickRacing | 0:9fe5d80c3c5e | 228 | if (scaledPV > 1.0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 229 | scaledPV = 1.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 230 | } else if (scaledPV < 0.0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 231 | scaledPV = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 232 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 233 | |
| WarwickRacing | 0:9fe5d80c3c5e | 234 | float scaledSP = (setPoint_ - inMin_) / inSpan_; |
| WarwickRacing | 0:9fe5d80c3c5e | 235 | if (scaledSP > 1.0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 236 | scaledSP = 1; |
| WarwickRacing | 0:9fe5d80c3c5e | 237 | } else if (scaledSP < 0.0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 238 | scaledSP = 0; |
| WarwickRacing | 0:9fe5d80c3c5e | 239 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 240 | |
| WarwickRacing | 0:9fe5d80c3c5e | 241 | float error = scaledSP - scaledPV; |
| WarwickRacing | 0:9fe5d80c3c5e | 242 | |
| WarwickRacing | 0:9fe5d80c3c5e | 243 | //Check and see if the output is pegged at a limit and only |
| WarwickRacing | 0:9fe5d80c3c5e | 244 | //integrate if it is not. This is to prevent reset-windup. |
| WarwickRacing | 0:9fe5d80c3c5e | 245 | if (!(prevControllerOutput_ >= 1 && error > 0) && !(prevControllerOutput_ <= 0 && error < 0)) { |
| WarwickRacing | 0:9fe5d80c3c5e | 246 | accError_ += error; |
| WarwickRacing | 0:9fe5d80c3c5e | 247 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 248 | |
| WarwickRacing | 0:9fe5d80c3c5e | 249 | //Compute the current slope of the input signal. |
| WarwickRacing | 0:9fe5d80c3c5e | 250 | float dMeas = (scaledPV - prevProcessVariable_) / tSample_; |
| WarwickRacing | 0:9fe5d80c3c5e | 251 | |
| WarwickRacing | 0:9fe5d80c3c5e | 252 | float scaledBias = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 253 | |
| WarwickRacing | 0:9fe5d80c3c5e | 254 | if (usingFeedForward) { |
| WarwickRacing | 0:9fe5d80c3c5e | 255 | scaledBias = (bias_ - outMin_) / outSpan_; |
| WarwickRacing | 0:9fe5d80c3c5e | 256 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 257 | |
| WarwickRacing | 0:9fe5d80c3c5e | 258 | //Perform the PID calculation. |
| WarwickRacing | 0:9fe5d80c3c5e | 259 | controllerOutput_ = scaledBias + Kc_ * (error + (tauR_ * accError_) - (tauD_ * dMeas)); |
| WarwickRacing | 0:9fe5d80c3c5e | 260 | |
| WarwickRacing | 0:9fe5d80c3c5e | 261 | //Make sure the computed output is within output constraints. |
| WarwickRacing | 0:9fe5d80c3c5e | 262 | if (controllerOutput_ < 0.0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 263 | controllerOutput_ = 0.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 264 | } else if (controllerOutput_ > 1.0) { |
| WarwickRacing | 0:9fe5d80c3c5e | 265 | controllerOutput_ = 1.0; |
| WarwickRacing | 0:9fe5d80c3c5e | 266 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 267 | |
| WarwickRacing | 0:9fe5d80c3c5e | 268 | //Remember this output for the windup check next time. |
| WarwickRacing | 0:9fe5d80c3c5e | 269 | prevControllerOutput_ = controllerOutput_; |
| WarwickRacing | 0:9fe5d80c3c5e | 270 | //Remember the input for the derivative calculation next time. |
| WarwickRacing | 0:9fe5d80c3c5e | 271 | prevProcessVariable_ = scaledPV; |
| WarwickRacing | 0:9fe5d80c3c5e | 272 | |
| WarwickRacing | 0:9fe5d80c3c5e | 273 | //Scale the output from percent span back out to a real world number. |
| WarwickRacing | 0:9fe5d80c3c5e | 274 | return ((controllerOutput_ * outSpan_) + outMin_); |
| WarwickRacing | 0:9fe5d80c3c5e | 275 | |
| WarwickRacing | 0:9fe5d80c3c5e | 276 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 277 | |
| WarwickRacing | 0:9fe5d80c3c5e | 278 | float PID::getInMin() { |
| WarwickRacing | 0:9fe5d80c3c5e | 279 | |
| WarwickRacing | 0:9fe5d80c3c5e | 280 | return inMin_; |
| WarwickRacing | 0:9fe5d80c3c5e | 281 | |
| WarwickRacing | 0:9fe5d80c3c5e | 282 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 283 | |
| WarwickRacing | 0:9fe5d80c3c5e | 284 | float PID::getInMax() { |
| WarwickRacing | 0:9fe5d80c3c5e | 285 | |
| WarwickRacing | 0:9fe5d80c3c5e | 286 | return inMax_; |
| WarwickRacing | 0:9fe5d80c3c5e | 287 | |
| WarwickRacing | 0:9fe5d80c3c5e | 288 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 289 | |
| WarwickRacing | 0:9fe5d80c3c5e | 290 | float PID::getOutMin() { |
| WarwickRacing | 0:9fe5d80c3c5e | 291 | |
| WarwickRacing | 0:9fe5d80c3c5e | 292 | return outMin_; |
| WarwickRacing | 0:9fe5d80c3c5e | 293 | |
| WarwickRacing | 0:9fe5d80c3c5e | 294 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 295 | |
| WarwickRacing | 0:9fe5d80c3c5e | 296 | float PID::getOutMax() { |
| WarwickRacing | 0:9fe5d80c3c5e | 297 | |
| WarwickRacing | 0:9fe5d80c3c5e | 298 | return outMax_; |
| WarwickRacing | 0:9fe5d80c3c5e | 299 | |
| WarwickRacing | 0:9fe5d80c3c5e | 300 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 301 | |
| WarwickRacing | 0:9fe5d80c3c5e | 302 | float PID::getInterval() { |
| WarwickRacing | 0:9fe5d80c3c5e | 303 | |
| WarwickRacing | 0:9fe5d80c3c5e | 304 | return tSample_; |
| WarwickRacing | 0:9fe5d80c3c5e | 305 | |
| WarwickRacing | 0:9fe5d80c3c5e | 306 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 307 | |
| WarwickRacing | 0:9fe5d80c3c5e | 308 | float PID::getPParam() { |
| WarwickRacing | 0:9fe5d80c3c5e | 309 | |
| WarwickRacing | 0:9fe5d80c3c5e | 310 | return pParam_; |
| WarwickRacing | 0:9fe5d80c3c5e | 311 | |
| WarwickRacing | 0:9fe5d80c3c5e | 312 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 313 | |
| WarwickRacing | 0:9fe5d80c3c5e | 314 | float PID::getIParam() { |
| WarwickRacing | 0:9fe5d80c3c5e | 315 | |
| WarwickRacing | 0:9fe5d80c3c5e | 316 | return iParam_; |
| WarwickRacing | 0:9fe5d80c3c5e | 317 | |
| WarwickRacing | 0:9fe5d80c3c5e | 318 | } |
| WarwickRacing | 0:9fe5d80c3c5e | 319 | |
| WarwickRacing | 0:9fe5d80c3c5e | 320 | float PID::getDParam() { |
| WarwickRacing | 0:9fe5d80c3c5e | 321 | |
| WarwickRacing | 0:9fe5d80c3c5e | 322 | return dParam_; |
| WarwickRacing | 0:9fe5d80c3c5e | 323 | |
| WarwickRacing | 0:9fe5d80c3c5e | 324 | } |