1 /* Copyright 2002-2021 CS GROUP
2 * Licensed to CS GROUP (CS) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * CS licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.orekit.forces.maneuvers.propulsion;
19
20 import java.util.ArrayList;
21 import java.util.Collections;
22 import java.util.List;
23
24 import org.hipparchus.CalculusFieldElement;
25 import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
26 import org.hipparchus.geometry.euclidean.threed.Vector3D;
27 import org.hipparchus.util.FastMath;
28 import org.orekit.utils.ParameterDriver;
29
30 /** Thrust propulsion model with parameters (for estimation) represented by scale factors
31 * on the X, Y and Z axis of the spacecraft frame.
32 * @author Maxime Journot
33 * @since 10.2
34 */
35 public class ScaledConstantThrustPropulsionModel extends AbstractConstantThrustPropulsionModel {
36
37 /** Parameter name for the scale factor on the X component of the thrust in S/C frame. */
38 public static final String THRUSTX_SCALE_FACTOR = "TX scale factor";
39 /** Parameter name for the scale factor on the Y component of the thrust in S/C frame. */
40 public static final String THRUSTY_SCALE_FACTOR = "TY scale factor";
41 /** Parameter name for the scale factor on the Z component of the thrust in S/C frame. */
42 public static final String THRUSTZ_SCALE_FACTOR = "TZ scale factor";
43
44 /** Thrust scaling factor.
45 * <p>
46 * We use a power of 2 to avoid numeric noise introduction
47 * in the multiplications/divisions sequences.
48 * </p>
49 */
50 private static final double THRUST_SCALE = FastMath.scalb(1.0, -5);
51
52 /** Parameter driver for the scale factor on the X component of the thrust in S/C frame. */
53 private final ParameterDriver scaleFactorThrustXDriver;
54 /** Parameter driver for the scale factor on the Y component of the thrust in S/C frame. */
55 private final ParameterDriver scaleFactorThrustYDriver;
56 /** Parameter driver for the scale factor on the Z component of the thrust in S/C frame. */
57 private final ParameterDriver scaleFactorThrustZDriver;
58
59 /** Constructor with min/max deviation for the scale factors.
60 * Typical usage is, for example, if you know that your propulsion system
61 * usually has an error of less than 10% then set the min/max to respectively 0.9 and 1.1.
62 * @param thrust the thrust (N)
63 * @param isp the isp (s)
64 * @param direction in spacecraft frame
65 * @param name the name of the maneuver
66 */
67 public ScaledConstantThrustPropulsionModel(final double thrust,
68 final double isp,
69 final Vector3D direction,
70 final String name) {
71 super(thrust, isp, direction, name);
72
73 // Build the parameter drivers, using maneuver name as prefix
74 this.scaleFactorThrustXDriver = new ParameterDriver(name + THRUSTX_SCALE_FACTOR, 1., THRUST_SCALE,
75 Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
76 this.scaleFactorThrustYDriver = new ParameterDriver(name + THRUSTY_SCALE_FACTOR, 1., THRUST_SCALE,
77 Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
78 this.scaleFactorThrustZDriver = new ParameterDriver(name + THRUSTZ_SCALE_FACTOR, 1., THRUST_SCALE,
79 Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
80 }
81
82 /** Get the thrust vector in S/C frame from scale factors (N).
83 * @param scaleFactorX thrust vector scale factor on X axis of S/C frame
84 * @param scaleFactorY thrust vector scale factor on Y axis of S/C frame
85 * @param scaleFactorZ thrust vector scale factor on Z axis of S/C frame
86 * @return thrust vector in S/C frame
87 */
88 private Vector3D getThrustVector(final double scaleFactorX,
89 final double scaleFactorY,
90 final double scaleFactorZ) {
91 return new Vector3D(getInitialThrustVector().getX() * scaleFactorX,
92 getInitialThrustVector().getY() * scaleFactorY,
93 getInitialThrustVector().getZ() * scaleFactorZ);
94 }
95
96 /** {@inheritDoc} */
97 @Override
98 public Vector3D getThrustVector() {
99 return getThrustVector(scaleFactorThrustXDriver.getValue(),
100 scaleFactorThrustYDriver.getValue(),
101 scaleFactorThrustZDriver.getValue());
102 }
103
104 /** {@inheritDoc} */
105 @Override
106 public double getFlowRate() {
107 return getInitialFlowrate();
108 }
109
110 /** {@inheritDoc} */
111 @Override
112 public List<ParameterDriver> getParametersDrivers() {
113 final List<ParameterDriver> drivers = new ArrayList<>(3);
114 drivers.add(scaleFactorThrustXDriver);
115 drivers.add(scaleFactorThrustYDriver);
116 drivers.add(scaleFactorThrustZDriver);
117 return Collections.unmodifiableList(drivers);
118 }
119
120 /** {@inheritDoc} */
121 @Override
122 public Vector3D getThrustVector(final double parameters[]) {
123 return getThrustVector(parameters[0], parameters[1], parameters[2]);
124 }
125
126 /** {@inheritDoc} */
127 @Override
128 public double getFlowRate(final double[] parameters) {
129 return getInitialFlowrate();
130 }
131
132 /** {@inheritDoc} */
133 @Override
134 public <T extends CalculusFieldElement<T>> FieldVector3D<T> getThrustVector(final T parameters[]) {
135 return new FieldVector3D<T>(parameters[0].multiply(getInitialThrustVector().getX()),
136 parameters[1].multiply(getInitialThrustVector().getY()),
137 parameters[2].multiply(getInitialThrustVector().getZ()));
138 }
139
140 /** {@inheritDoc} */
141 @Override
142 public <T extends CalculusFieldElement<T>> T getFlowRate(final T[] parameters) {
143 return parameters[0].getField().getZero().add(getInitialFlowrate());
144 }
145 }