SimpleDirectedControlSampler.cpp
1 /*********************************************************************
2 * Software License Agreement (BSD License)
3 *
4 * Copyright (c) 2011, Willow Garage, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following
15 * disclaimer in the documentation and/or other materials provided
16 * with the distribution.
17 * * Neither the name of the Willow Garage nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
29 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
31 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32 * POSSIBILITY OF SUCH DAMAGE.
33 *********************************************************************/
34 
35 /* Author: Ioan Sucan */
36 
37 #include "ompl/control/SimpleDirectedControlSampler.h"
38 #include "ompl/control/SpaceInformation.h"
39 
41  : DirectedControlSampler(si), cs_(si->allocControlSampler()), numControlSamples_(k)
42 {
43 }
44 
45 ompl::control::SimpleDirectedControlSampler::~SimpleDirectedControlSampler() = default;
46 
48  base::State *dest)
49 {
50  return getBestControl(control, source, dest, nullptr);
51 }
52 
54  const base::State *source, base::State *dest)
55 {
56  return getBestControl(control, source, dest, previous);
57 }
58 
60  base::State *dest, const Control *previous)
61 {
62  // Sample the first control
63  if (previous)
64  cs_->sampleNext(control, previous, source);
65  else
66  cs_->sample(control, source);
67 
68  const unsigned int minDuration = si_->getMinControlDuration();
69  const unsigned int maxDuration = si_->getMaxControlDuration();
70 
71  unsigned int steps = cs_->sampleStepCount(minDuration, maxDuration);
72  // Propagate the first control, and find how far it is from the target state
73  base::State *bestState = si_->allocState();
74  steps = si_->propagateWhileValid(source, control, steps, bestState);
75 
76  if (numControlSamples_ > 1)
77  {
78  Control *tempControl = si_->allocControl();
79  base::State *tempState = si_->allocState();
80  double bestDistance = si_->distance(bestState, dest);
81 
82  // Sample k-1 more controls, and save the control that gets closest to target
83  for (unsigned int i = 1; i < numControlSamples_; ++i)
84  {
85  unsigned int sampleSteps = cs_->sampleStepCount(minDuration, maxDuration);
86  if (previous)
87  cs_->sampleNext(tempControl, previous, source);
88  else
89  cs_->sample(tempControl, source);
90 
91  sampleSteps = si_->propagateWhileValid(source, tempControl, sampleSteps, tempState);
92  double tempDistance = si_->distance(tempState, dest);
93  if (tempDistance < bestDistance)
94  {
95  si_->copyState(bestState, tempState);
96  si_->copyControl(control, tempControl);
97  bestDistance = tempDistance;
98  steps = sampleSteps;
99  }
100  }
101 
102  si_->freeState(tempState);
103  si_->freeControl(tempControl);
104  }
105 
106  si_->copyState(dest, bestState);
107  si_->freeState(bestState);
108 
109  return steps;
110 }
unsigned int getMinControlDuration() const
Get the minimum number of steps a control is propagated for.
unsigned int propagateWhileValid(const base::State *state, const Control *control, int steps, base::State *result) const
Propagate the model of the system forward, starting at a given state, with a given control...
Definition of an abstract control.
Definition: Control.h:47
void freeState(State *state) const
Free the memory of a state.
virtual unsigned int getBestControl(Control *control, const base::State *source, base::State *dest, const Control *previous)
Samples numControlSamples_ controls, and returns the control that brings the system the closest to ta...
unsigned int sampleTo(Control *control, const base::State *source, base::State *dest) override
Sample a control given that it will be applied to state state and the intention is to reach state des...
State * allocState() const
Allocate memory for a state.
Control * allocControl() const
Allocate memory for a control.
SimpleDirectedControlSampler(const SpaceInformation *si, unsigned int k=1)
Constructor takes the state space to construct samples for as argument Optionally, a k value can be given to indicate the number of controls to try when directing a system toward a specific state. Default value is 1.
void copyControl(Control *destination, const Control *source) const
Copy a control to another.
void copyState(State *destination, const State *source) const
Copy a state to another.
unsigned int getMaxControlDuration() const
Get the maximum number of steps a control is propagated for.
ControlSamplerPtr cs_
An instance of the control sampler.
Abstract definition of a directed control sampler. Motion planners that need to sample controls that ...
Definition of an abstract state.
Definition: State.h:49
const SpaceInformation * si_
The space information this sampler operates on.
void freeControl(Control *control) const
Free the memory of a control.
Space information containing necessary information for planning with controls. setup() needs to be ca...
unsigned int numControlSamples_
The number of controls to sample when finding the best control.
double distance(const State *state1, const State *state2) const
Compute the distance between two states.