Files
ODrive/Firmware/Tests/test_trap_traj.cpp
2020-09-05 00:23:58 -04:00

236 lines
7.6 KiB
C++

#include <doctest.h>
#include <limits.h>
#include <cmath>
#include <iostream>
#include <random>
#include "MotorControl/utils.hpp"
// TODO: This is currently a copy-paste of the real code due to non-trivial
// include dependencies. Should include real code.
class TrapezoidalTrajectory {
public:
struct Step_t {
float Y;
float Yd;
float Ydd;
};
explicit TrapezoidalTrajectory();
bool planTrapezoidal(float Xf, float Xi, float Vi,
float Vmax, float Amax, float Dmax);
Step_t eval(float t);
float Xi_;
float Xf_;
float Vi_;
float Ar_;
float Vr_;
float Dr_;
float Ta_;
float Tv_;
float Td_;
float Tf_;
float yAccel_;
float t_;
};
// A sign function where input 0 has positive sign (not 0)
float sign_hard(float val) {
return (std::signbit(val)) ? -1.0f : 1.0f;
}
// Symbol Description
// Ta, Tv and Td Duration of the stages of the AL profile
// Xi and Vi Adapted initial conditions for the AL profile
// Xf Position set-point
// s Direction (sign) of the trajectory
// Vmax, Amax, Dmax and jmax Kinematic bounds
// Ar, Dr and Vr Reached values of acceleration and velocity
TrapezoidalTrajectory::TrapezoidalTrajectory() {}
bool TrapezoidalTrajectory::planTrapezoidal(float Xf, float Xi, float Vi,
float Vmax, float Amax, float Dmax) {
float dX = Xf - Xi; // Distance to travel
float stop_dist = (Vi * Vi) / (2.0f * Dmax); // Minimum stopping distance
float dXstop = std::copysign(stop_dist, Vi); // Minimum stopping displacement
float s = sign_hard(dX - dXstop); // Sign of coast velocity (if any)
Ar_ = s * Amax; // Maximum Acceleration (signed)
Dr_ = -s * Dmax; // Maximum Deceleration (signed)
Vr_ = s * Vmax; // Maximum Velocity (signed)
// If we start with a speed faster than cruising, then we need to decel instead of accel
// aka "double deceleration move" in the paper
if ((s * Vi) > (s * Vr_)) {
Ar_ = -s * Amax;
}
// Time to accel/decel to/from Vr (cruise speed)
Ta_ = (Vr_ - Vi) / Ar_;
Td_ = -Vr_ / Dr_;
// Integral of velocity ramps over the full accel and decel times to get
// minimum displacement required to reach cuising speed
float dXmin = 0.5f*Ta_*(Vr_ + Vi) + 0.5f*Td_*Vr_;
// Are we displacing enough to reach cruising speed?
if (s*dX < s*dXmin) {
// Short move (triangle profile)
Vr_ = s * std::sqrt(std::max((Dr_*SQ(Vi) + 2*Ar_*Dr_*dX) / (Dr_ - Ar_), 0.0f));
//Vr_ = s * std::sqrt((Dr_*SQ(Vi) + 2*Ar_*Dr_*dX) / (Dr_ - Ar_));
Ta_ = std::max(0.0f, (Vr_ - Vi) / Ar_);
Td_ = std::max(0.0f, -Vr_ / Dr_);
Tv_ = 0.0f;
} else {
// Long move (trapezoidal profile)
Tv_ = (dX - dXmin) / Vr_;
}
// Fill in the rest of the values used at evaluation-time
Tf_ = Ta_ + Tv_ + Td_;
Xi_ = Xi;
Xf_ = Xf;
Vi_ = Vi;
yAccel_ = Xi + Vi*Ta_ + 0.5f*Ar_*SQ(Ta_); // pos at end of accel phase
return true;
}
TrapezoidalTrajectory::Step_t TrapezoidalTrajectory::eval(float t) {
Step_t trajStep;
if (t < 0.0f) { // Initial Condition
trajStep.Y = Xi_;
trajStep.Yd = Vi_;
trajStep.Ydd = 0.0f;
} else if (t < Ta_) { // Accelerating
trajStep.Y = Xi_ + Vi_*t + 0.5f*Ar_*SQ(t);
trajStep.Yd = Vi_ + Ar_*t;
trajStep.Ydd = Ar_;
} else if (t < Ta_ + Tv_) { // Coasting
trajStep.Y = yAccel_ + Vr_*(t - Ta_);
trajStep.Yd = Vr_;
trajStep.Ydd = 0.0f;
} else if (t < Tf_) { // Deceleration
float td = t - Tf_;
trajStep.Y = Xf_ + 0.5f*Dr_*SQ(td);
trajStep.Yd = Dr_*td;
trajStep.Ydd = Dr_;
} else if (t >= Tf_) { // Final Condition
trajStep.Y = Xf_;
trajStep.Yd = 0.0f;
trajStep.Ydd = 0.0f;
} else {
// TODO: report error here
}
return trajStep;
}
static_assert(sizeof(float) * CHAR_BIT == 32);
void run_trajectory_test(float goal, float position, float velocity, float Vmax, float Amax, float Dmax) {
float dt = 0.000125f;
int replan_interval = 10; // must be > 2 (see note below)
float t = 0.0f;
float Vmax_test = std::max(Vmax, std::abs(velocity));
TrapezoidalTrajectory traj{};
int replan_counter = 0;
do {
if (replan_counter <= 0) {
CHECK(traj.planTrapezoidal(goal, position, velocity, Vmax, Amax, Dmax));
t = 0.0f;
replan_counter = replan_interval;
} else {
replan_counter--;
}
TrapezoidalTrajectory::Step_t step = traj.eval(t);
t += dt;
//std::cerr << "vel: " << step.Yd << ", pos: " << step.Y << "\n";
// Check if acceleration within bounds
if (velocity >= 0.0f) {
CHECK(step.Ydd <= Amax);
CHECK(step.Ydd >= -Dmax);
CHECK((step.Yd - velocity) / dt <= Amax * 1.002f);
CHECK((step.Yd - velocity) / dt >= -Dmax * 1.002f);
} else {
CHECK(step.Ydd <= Dmax);
CHECK(step.Ydd >= -Amax);
CHECK((step.Yd - velocity) / dt <= Dmax * 1.002f);
CHECK((step.Yd - velocity) / dt >= -Amax * 1.002f);
}
// Check if velocity within bounds
CHECK(step.Yd >= -Vmax_test);
CHECK(step.Yd <= Vmax_test);
CHECK((step.Y - position) / dt >= -Vmax_test * 1.002f);
CHECK((step.Y - position) / dt <= Vmax_test * 1.002f);
velocity = step.Yd;
// Check if position is making progress
// TODO: the trajectory planner currently needs three "warm-up" iterations
// until its position makes progress. This should probably be revisited.
// TODO: this is disabled currently because there are legitimate trajectories
// where the position first moves in the wrong direction.
//if ((replan_counter < replan_interval - 2) && (t <= traj.Tf_)) {
// CHECK(std::abs(step.Y - goal) < std::abs(position - goal));
//}
position = step.Y;
} while (t <= traj.Tf_);
CHECK(position >= goal - 1.0f);
CHECK(position <= goal + 1.0f);
CHECK(velocity >= -Dmax * dt);
CHECK(velocity <= Dmax * dt);
}
TEST_SUITE("Trajectory Planner") {
// these form a triangle trajectory because 2*v^2/(2*a) = 2 * 27712^2 / (2*22288) = 34456 > 16384
TEST_CASE("neg-dir-triangle") {
run_trajectory_test(-8192.0f, 8192.0f, 0.0f, 27712.0f, 22288.0f, 22288.0f);
}
TEST_CASE("pos-dir-triangle") {
run_trajectory_test(8192.0f, -8192.0f, 0.0f, 27712.0f, 22288.0f, 22288.0f);
}
// these form a trapezoid trajectory because 2*v^2/(2*a) = 2 * 27712^2 / (2*22288) = 34456 < 16384
TEST_CASE("neg-dir-trapezoid") {
run_trajectory_test(-25000.0f, 25000.0f, 0.0f, 27712.0f, 22288.0f, 22288.0f);
}
TEST_CASE("pos-dir-trapezoid") {
run_trajectory_test(25000.0f, -25000.0f, 0.0f, 27712.0f, 22288.0f, 22288.0f);
}
// for the following tests note that v^2/(2*a) = 27712^2 / (2*22288) = 17227 > 16384
TEST_CASE("neg-dir-not-enough-braking-distance") {
run_trajectory_test(-8192.0f, 8192.0f, -27712.0f, 27712.0f, 22288.0f, 22288.0f);
}
TEST_CASE("pos-dir-not-enough-braking-distance") {
run_trajectory_test(8192.0f, -8192.0f, 27712.0f, 27712.0f, 22288.0f, 22288.0f);
}
TEST_CASE("neg-dir-over-speed") {
run_trajectory_test(-8192.0f, 8192.0f, -40000.0f, 27712.0f, 22288.0f, 22288.0f);
}
TEST_CASE("pos-dir-over-speed") {
run_trajectory_test(8192.0f, -8192.0f, 40000.0f, 27712.0f, 22288.0f, 22288.0f);
}
}