1 package org.opentrafficsim.road.gtu.lane.tactical.following;
2
3 import java.io.Serializable;
4
5 import org.djunits.unit.AccelerationUnit;
6 import org.djunits.unit.DurationUnit;
7 import org.djunits.unit.LengthUnit;
8 import org.djunits.unit.SpeedUnit;
9 import org.djunits.value.vdouble.scalar.Acceleration;
10 import org.djunits.value.vdouble.scalar.Duration;
11 import org.djunits.value.vdouble.scalar.Length;
12 import org.djunits.value.vdouble.scalar.Speed;
13 import org.opentrafficsim.base.parameters.ParameterException;
14 import org.opentrafficsim.base.parameters.Parameters;
15 import org.opentrafficsim.road.gtu.lane.perception.PerceptionIterable;
16 import org.opentrafficsim.road.gtu.lane.perception.headway.Headway;
17 import org.opentrafficsim.road.network.speed.SpeedLimitInfo;
18 import org.opentrafficsim.road.network.speed.SpeedLimitTypes;
19
20
21
22
23
24
25
26
27
28
29
30 public class IDMOld extends AbstractGTUFollowingModelMobil implements Serializable
31 {
32
33 private static final long serialVersionUID = 20141119L;
34
35
36 private final Length s0;
37
38
39 private Acceleration a;
40
41
42 private final Acceleration b;
43
44
45 private Duration tSafe;
46
47
48
49
50
51 private static final Duration DEFAULT_STEP_SIZE = new Duration(0.5, DurationUnit.SECOND);
52
53
54
55
56
57 private double delta;
58
59
60
61
62 public IDMOld()
63 {
64 this.a = new Acceleration(1.56, AccelerationUnit.METER_PER_SECOND_2);
65 this.b = new Acceleration(2.09, AccelerationUnit.METER_PER_SECOND_2);
66 this.s0 = new Length(3, LengthUnit.METER);
67 this.tSafe = new Duration(1.2, DurationUnit.SECOND);
68 this.delta = 1.0;
69 }
70
71
72
73
74
75
76
77
78
79
80 public IDMOld(final Acceleration a, final Acceleration b, final Length s0, final Duration tSafe, final double delta)
81 {
82 this.a = a;
83 this.b = b;
84 this.s0 = s0;
85 this.tSafe = tSafe;
86 this.delta = delta;
87 }
88
89
90
91
92
93
94
95 private Speed vDes(final Speed speedLimit, final Speed followerMaximumSpeed)
96 {
97 return new Speed(Math.min(this.delta * speedLimit.getSI(), followerMaximumSpeed.getSI()), SpeedUnit.SI);
98 }
99
100
101 @Override
102 public final Acceleration computeAcceleration(final Speed followerSpeed, final Speed followerMaximumSpeed,
103 final Speed leaderSpeed, final Length headway, final Speed speedLimit)
104 {
105 return computeAcceleration(followerSpeed, followerMaximumSpeed, leaderSpeed, headway, speedLimit, DEFAULT_STEP_SIZE);
106 }
107
108
109 @Override
110 public final Acceleration computeAcceleration(final Speed followerSpeed, final Speed followerMaximumSpeed,
111 final Speed leaderSpeed, final Length headway, final Speed speedLimit, final Duration stepSize)
112 {
113
114
115 Speed dV = followerSpeed.minus(leaderSpeed);
116 double sStar = this.s0.si + followerSpeed.si * this.tSafe.si
117 + dV.si * followerSpeed.si / (2.0 * Math.sqrt(this.a.si * this.b.si));
118 if (sStar < 0.0 && headway.si < 0.0)
119 {
120 return new Acceleration(Double.NEGATIVE_INFINITY, AccelerationUnit.SI);
121 }
122 sStar = sStar >= 0.0 ? sStar : 0.0;
123 double s = headway.si > 0.0 ? headway.si : 1E-99;
124 Acceleration aInteraction = new Acceleration(this.a.si * (sStar / s) * (sStar / s), AccelerationUnit.SI);
125 Acceleration aFree =
126 new Acceleration(this.a.si * (1.0 - Math.pow(followerSpeed.si / vDes(speedLimit, followerMaximumSpeed).si, 4)),
127 AccelerationUnit.SI);
128
129 if (aFree.si < -0.5)
130 {
131 aFree = new Acceleration(-0.5, AccelerationUnit.SI);
132 }
133 Acceleration newAcceleration = aFree.minus(aInteraction);
134 if (newAcceleration.si * stepSize.si + followerSpeed.si < 0)
135 {
136 newAcceleration = new Acceleration(-followerSpeed.si / stepSize.si, AccelerationUnit.SI);
137 }
138 return newAcceleration;
139 }
140
141
142 @Override
143 public final Duration getStepSize()
144 {
145 return DEFAULT_STEP_SIZE;
146 }
147
148
149 @Override
150 public final Acceleration getMaximumSafeDeceleration()
151 {
152 return this.b;
153 }
154
155
156 @Override
157 public final String getName()
158 {
159 return "IDM";
160 }
161
162
163 @Override
164 public final String getLongName()
165 {
166 return String.format("%s (a=%.1fm/s\u00b2, b=%.1fm/s\u00b2, s0=%.1fm, tSafe=%.1fs, delta=%.2f)", getName(),
167 this.a.getSI(), this.b.getSI(), this.s0.getSI(), this.tSafe.getSI(), this.delta);
168 }
169
170
171 @Override
172 public final void setA(final Acceleration a)
173 {
174 this.a = a;
175 }
176
177
178 @Override
179 public final void setT(final Duration t)
180 {
181 this.tSafe = t;
182 }
183
184
185 @Override
186 public final void setFspeed(final double fSpeed)
187 {
188 this.delta = fSpeed;
189 }
190
191
192
193
194 @Override
195 public final Speed desiredSpeed(final Parameters parameters, final SpeedLimitInfo speedInfo) throws ParameterException
196 {
197 throw new UnsupportedOperationException("Old car-following model does not support desired speed.");
198 }
199
200
201 @Override
202 public final Length desiredHeadway(final Parameters parameters, final Speed speed) throws ParameterException
203 {
204 throw new UnsupportedOperationException("Old car-following model does not support desired headway.");
205 }
206
207
208 @Override
209 public final Acceleration followingAcceleration(final Parameters parameters, final Speed speed,
210 final SpeedLimitInfo speedInfo, final PerceptionIterable<? extends Headway> leaders) throws ParameterException
211 {
212 Length headway;
213 Speed leaderSpeed;
214 if (leaders.isEmpty())
215 {
216 headway = new Length(Double.MAX_VALUE, LengthUnit.SI);
217 leaderSpeed = speed;
218 }
219 else
220 {
221 Headway leader = leaders.first();
222 headway = leader.getDistance();
223 leaderSpeed = leader.getSpeed();
224 }
225 return this.computeAcceleration(speed, speedInfo.getSpeedInfo(SpeedLimitTypes.MAX_VEHICLE_SPEED), leaderSpeed, headway,
226 speedInfo.getSpeedInfo(SpeedLimitTypes.FIXED_SIGN));
227 }
228
229
230 @Override
231 public final String toString()
232 {
233 return "IDMOld [s0=" + this.s0 + ", a=" + this.a + ", b=" + this.b + ", tSafe=" + this.tSafe + ", stepSize="
234 + DEFAULT_STEP_SIZE + ", delta=" + this.delta + "]";
235 }
236
237 }