1 package org.opentrafficsim.road.gtu.lane.tactical.following;
2
3 import java.io.Serializable;
4 import java.util.SortedMap;
5
6 import org.djunits.unit.AccelerationUnit;
7 import org.djunits.unit.LengthUnit;
8 import org.djunits.unit.SpeedUnit;
9 import org.djunits.unit.TimeUnit;
10 import org.djunits.value.vdouble.scalar.Acceleration;
11 import org.djunits.value.vdouble.scalar.Duration;
12 import org.djunits.value.vdouble.scalar.Length;
13 import org.djunits.value.vdouble.scalar.Speed;
14 import org.opentrafficsim.core.gtu.behavioralcharacteristics.BehavioralCharacteristics;
15 import org.opentrafficsim.core.gtu.behavioralcharacteristics.ParameterException;
16 import org.opentrafficsim.road.network.speed.SpeedLimitInfo;
17
18
19
20
21
22
23
24
25
26
27
28 public class IDMOld extends AbstractGTUFollowingModelMobil implements Serializable
29 {
30
31 private static final long serialVersionUID = 20141119L;
32
33
34 private final Length s0;
35
36
37 private Acceleration a;
38
39
40 private final Acceleration b;
41
42
43 private Duration tSafe;
44
45
46
47
48
49 private static final Duration DEFAULT_STEP_SIZE = new Duration(0.5, TimeUnit.SECOND);
50
51
52
53
54
55 private double delta;
56
57
58
59
60 public IDMOld()
61 {
62 this.a = new Acceleration(1.56, AccelerationUnit.METER_PER_SECOND_2);
63 this.b = new Acceleration(2.09, AccelerationUnit.METER_PER_SECOND_2);
64 this.s0 = new Length(3, LengthUnit.METER);
65 this.tSafe = new Duration(1.2, TimeUnit.SECOND);
66 this.delta = 1.0;
67 }
68
69
70
71
72
73
74
75
76
77
78 public IDMOld(final Acceleration a, final Acceleration b, final Length s0, final Duration tSafe, final double delta)
79 {
80 this.a = a;
81 this.b = b;
82 this.s0 = s0;
83 this.tSafe = tSafe;
84 this.delta = delta;
85 }
86
87
88
89
90
91
92
93 private Speed vDes(final Speed speedLimit, final Speed followerMaximumSpeed)
94 {
95 return new Speed(Math.min(this.delta * speedLimit.getSI(), followerMaximumSpeed.getSI()), SpeedUnit.SI);
96 }
97
98
99 @Override
100 public final Acceleration computeAcceleration(final Speed followerSpeed, final Speed followerMaximumSpeed,
101 final Speed leaderSpeed, final Length headway, final Speed speedLimit)
102 {
103 return computeAcceleration(followerSpeed, followerMaximumSpeed, leaderSpeed, headway, speedLimit, DEFAULT_STEP_SIZE);
104 }
105
106
107 @Override
108 public final Acceleration computeAcceleration(final Speed followerSpeed, final Speed followerMaximumSpeed,
109 final Speed leaderSpeed, final Length headway, final Speed speedLimit, final Duration stepSize)
110 {
111
112
113 Speed dV = followerSpeed.minus(leaderSpeed);
114 double sStar = this.s0.si + followerSpeed.si * this.tSafe.si
115 + dV.si * followerSpeed.si / (2.0 * Math.sqrt(this.a.si * this.b.si));
116 if (sStar < 0.0 && headway.si < 0.0)
117 {
118 return new Acceleration(Double.NEGATIVE_INFINITY, AccelerationUnit.SI);
119 }
120 sStar = sStar >= 0.0 ? sStar : 0.0;
121 double s = headway.si > 0.0 ? headway.si : 1E-99;
122 Acceleration aInteraction = new Acceleration(this.a.si * (sStar / s) * (sStar / s), AccelerationUnit.SI);
123 Acceleration aFree =
124 new Acceleration(this.a.si * (1.0 - Math.pow(followerSpeed.si / vDes(speedLimit, followerMaximumSpeed).si, 4)),
125 AccelerationUnit.SI);
126
127 if (aFree.si < -0.5)
128 {
129 aFree = new Acceleration(-0.5, AccelerationUnit.SI);
130 }
131 Acceleration newAcceleration = aFree.minus(aInteraction);
132 if (newAcceleration.si * stepSize.si + followerSpeed.si < 0)
133 {
134 newAcceleration = new Acceleration(-followerSpeed.si / stepSize.si, AccelerationUnit.SI);
135 }
136 return newAcceleration;
137 }
138
139
140 @Override
141 public final Duration getStepSize()
142 {
143 return DEFAULT_STEP_SIZE;
144 }
145
146
147 @Override
148 public final Acceleration getMaximumSafeDeceleration()
149 {
150 return this.b;
151 }
152
153
154 @Override
155 public final String getName()
156 {
157 return "IDM";
158 }
159
160
161 @Override
162 public final String getLongName()
163 {
164 return String.format("%s (a=%.1fm/s\u00b2, b=%.1fm/s\u00b2, s0=%.1fm, tSafe=%.1fs, delta=%.2f)", getName(),
165 this.a.getSI(), this.b.getSI(), this.s0.getSI(), this.tSafe.getSI(), this.delta);
166 }
167
168
169 @Override
170 public final void setA(final Acceleration a)
171 {
172 this.a = a;
173 }
174
175
176 @Override
177 public final void setT(final Duration t)
178 {
179 this.tSafe = t;
180 }
181
182
183 @Override
184 public final void setFspeed(final double fSpeed)
185 {
186 this.delta = fSpeed;
187 }
188
189
190
191
192 @Override
193 public final Speed desiredSpeed(final BehavioralCharacteristics behavioralCharacteristics, final SpeedLimitInfo speedInfo)
194 throws ParameterException
195 {
196 return null;
197 }
198
199
200 @Override
201 public final Length desiredHeadway(final BehavioralCharacteristics behavioralCharacteristics, final Speed speed)
202 throws ParameterException
203 {
204 return null;
205 }
206
207
208 @Override
209 public final Acceleration followingAcceleration(final BehavioralCharacteristics behavioralCharacteristics,
210 final Speed speed, final SpeedLimitInfo speedInfo, final SortedMap<Length, Speed> leaders) throws ParameterException
211 {
212 return null;
213 }
214
215
216 @Override
217 public final String toString()
218 {
219 return "IDMOld [s0=" + this.s0 + ", a=" + this.a + ", b=" + this.b + ", tSafe=" + this.tSafe + ", stepSize="
220 + DEFAULT_STEP_SIZE + ", delta=" + this.delta + "]";
221 }
222
223 }