parameters.cc
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29 
30 #include <towr/parameters.h>
32 
33 #include <algorithm>
34 #include <numeric> // std::accumulate
35 #include <math.h> // fabs
36 #include <cassert>
37 
38 namespace towr {
39 
41 {
42  // constructs optimization variables
45  ee_polynomials_per_swing_phase_ = 2; // so step can at least lift leg
46 
47  // parameters related to specific constraints (only used when it is added as well)
51  dt_constraint_base_motion_ = duration_base_polynomial_/4.; // only for base RoM constraint
52  bound_phase_duration_ = std::make_pair(0.2, 1.0); // used only when optimizing phase durations, so gait
53 
54  // a minimal set of basic constraints
55  constraints_.push_back(Terrain);
56  constraints_.push_back(Dynamic); //Ensures that the dynamic model is fullfilled at discrete times.
57  constraints_.push_back(BaseAcc); // so accelerations don't jump between polynomials
58  constraints_.push_back(EndeffectorRom); //Ensures that the range of motion is respected at discrete times.
59  constraints_.push_back(Force); // ensures unilateral forces and inside the friction cone.
60  constraints_.push_back(Swing); // creates smoother swing motions, not absolutely required.
61 
62  // optional costs to e.g penalize endeffector forces
63  // costs_.push_back({ForcesCostID, 1.0}); weighed by 1.0 relative to other costs
64 
65  // bounds on final 6DoF base state
70 
71  // additional restrictions are set directly on the variables in nlp_factory,
72  // such as e.g. initial and endeffector,...
73 }
74 
75 void
76 
78 {
79  constraints_.push_back(TotalTime);
80 }
81 
84 {
85  std::vector<double> base_spline_timings_;
86  double dt = duration_base_polynomial_;
87  double t_left = GetTotalTime ();
88 
89  double eps = 1e-10; // since repeated subtraction causes inaccuracies
90  while (t_left > eps) {
91  double duration = t_left>dt? dt : t_left;
92  base_spline_timings_.push_back(duration);
93 
94  t_left -= dt;
95  }
96 
97  return base_spline_timings_;
98 }
99 
100 int
102 {
103  return ee_phase_durations_.at(ee).size();
104 }
105 
106 int
108 {
109  return ee_in_contact_at_start_.size();
110 }
111 
112 double
114 {
115  std::vector<double> T_feet;
116 
117  for (const auto& v : ee_phase_durations_)
118  T_feet.push_back(std::accumulate(v.begin(), v.end(), 0.0));
119 
120  // safety check that all feet durations sum to same value
121  double T = T_feet.empty()? 0.0 : T_feet.front(); // take first foot as reference
122  for (double Tf : T_feet)
123  assert(fabs(Tf - T) < 1e-6);
124 
125  return T;
126 }
127 
128 bool
130 {
131  // if total time is constrained, then timings are optimized
133  auto v = constraints_; // shorthand
134  return std::find(v.begin(), v.end(), c) != v.end();
135 }
136 
137 } // namespace towr
std::pair< double, double > bound_phase_duration_
Definition: parameters.h:212
sets SplineAccConstraint
Definition: parameters.h:146
sets DynamicConstraint
Definition: parameters.h:139
int force_polynomials_per_stance_phase_
Number of polynomials to parameterize each contact force during stance phase.
Definition: parameters.h:195
sets RangeOfMotionConstraint
Definition: parameters.h:140
ConstraintName
Identifiers to be used to add certain constraints to the optimization problem.
Definition: parameters.h:139
double GetTotalTime() const
Total duration [s] of the motion.
Definition: parameters.cc:113
std::vector< int > bounds_final_ang_vel_
Definition: parameters.h:201
sets SwingConstraint
Definition: parameters.h:144
sets ForceConstraint
Definition: parameters.h:143
std::vector< int > bounds_final_lin_pos_
which dimensions (x,y,z) of the final base state should be bounded
Definition: parameters.h:201
VecTimes GetBasePolyDurations() const
The durations of each base polynomial in the spline (lin+ang).
Definition: parameters.cc:83
int ee_polynomials_per_swing_phase_
Number of polynomials to parameterize foot movement during swing phases.
Definition: parameters.h:192
double dt_constraint_range_of_motion_
Interval at which the range of motion constraint is enforced.
Definition: parameters.h:183
int GetEECount() const
The number of endeffectors.
Definition: parameters.cc:107
std::vector< int > bounds_final_lin_vel_
Definition: parameters.h:201
double duration_base_polynomial_
Fixed duration of each cubic polynomial describing the base motion.
Definition: parameters.h:189
double dt_constraint_dynamic_
Interval at which the dynamic constraint is enforced.
Definition: parameters.h:180
bool IsOptimizeTimings() const
True if the phase durations should be optimized over.
Definition: parameters.cc:129
std::vector< VecTimes > ee_phase_durations_
Number and initial duration of each foot&#39;s swing and stance phases.
Definition: parameters.h:168
void OptimizePhaseDurations()
Specifies that timings of all feet, so the gait, should be optimized.
Definition: parameters.cc:77
double force_limit_in_normal_direction_
The maximum allowable force [N] in normal direction.
Definition: parameters.h:198
sets TotalDurationConstraint
Definition: parameters.h:141
double dt_constraint_base_motion_
Interval at which the base motion constraint is enforced.
Definition: parameters.h:186
std::vector< double > VecTimes
Definition: parameters.h:158
std::vector< int > bounds_final_ang_pos_
Definition: parameters.h:201
Parameters()
Default parameters to get started.
Definition: parameters.cc:40
std::vector< bool > ee_in_contact_at_start_
True if the foot is initially in contact with the terrain.
Definition: parameters.h:171
UsedConstraints constraints_
Which constraints should be used in the optimization problem.
Definition: parameters.h:174
unsigned int EEID
Definition: parameters.h:159
int GetPhaseCount(EEID ee) const
The number of phases allowed for endeffector ee.
Definition: parameters.cc:101
sets TerrainConstraint
Definition: parameters.h:142


towr
Author(s): Alexander W. Winkler
autogenerated on Sat Apr 13 2019 02:28:00