Example 08: Per-section Minimum Trajectory Duration

C++

// This example shows the usage of intermediate waypoints. It will only work with Ruckig Pro or enabled Online API.
 
#include <iostream>
 
#include <ruckig/ruckig.hpp>
 
 
using namespace ruckig;
 
int main() {
    const double control_cycle {0.01};
    const size_t DOFs {3};
    const size_t max_number_of_waypoints {10};  // for memory allocation
 
    // Create instances: the Ruckig OTG as well as input and output parameters
    Ruckig<DOFs> otg {control_cycle, max_number_of_waypoints};
    InputParameter<DOFs> input;
    OutputParameter<DOFs> output {max_number_of_waypoints};
 
    // Set input parameters
    input.current_position = {0.8, 0.0, 0.5};
    input.current_velocity = {0.0, 0.0, 0.0};
    input.current_acceleration = {0.0, 0.0, 0.0};
 
    input.intermediate_positions = {
        {1.4, -1.6, 1.0},
        {-0.6, -0.5, 0.4},
        {-0.4, -0.35, 0.0},
        {-0.2, 0.35, -0.1},
        {0.2, 0.5, -0.1},
        {0.8, 1.8, -0.1}
    };
 
    input.target_position = {0.5, 1.2, 0.0};
    input.target_velocity = {0.0, 0.0, 0.0};
    input.target_acceleration = {0.0, 0.0, 0.0};
 
    input.max_velocity = {3.0, 2.0, 2.0};
    input.max_acceleration = {6.0, 4.0, 4.0};
    input.max_jerk = {16.0, 10.0, 20.0};
 
    // Define a minimum duration per section of the trajectory (number waypoints + 1)
    input.per_section_minimum_duration = {0, 2.0, 0.0, 1.0, 0.0, 2.0, 0};
 
    std::cout << "t | p1 | p2 | p3" << std::endl;
    double calculation_duration {0.0};
    while (otg.update(input, output) == Result::Working) {
        auto& p = output.new_position;
        std::cout << output.time << " " << p[0] << " " << p[1] << " " << p[2] << std::endl;
 
        output.pass_to_input(input);
 
        if (output.new_calculation) {
            calculation_duration = output.calculation_duration;
        }
    }
 
    std::cout << "Reached target position in " << output.trajectory.get_duration() << " [s]." << std::endl;
    std::cout << "Calculation in " << calculation_duration << " [µs]." << std::endl;
}

Python

# This example shows the usage of intermediate waypoints. It will only work with Ruckig Pro or enabled Online API (e.g. default when installed by pip / PyPI).
 
from copy import copy
from pathlib import Path
from sys import path
 
# Path to the build directory including a file similar to 'ruckig.cpython-37m-x86_64-linux-gnu'.
build_path = Path(__file__).parent.absolute().parent / 'build'
path.insert(0, str(build_path))
 
from ruckig import InputParameter, OutputParameter, Result, Ruckig
 
 
if __name__ == '__main__':
    # Create instances: the Ruckig OTG as well as input and output parameters
    otg = Ruckig(3, 0.01, 10)  # DoFs, control cycle rate, maximum number of intermediate waypoints for memory allocation
    inp = InputParameter(3)  # DoFs
    out = OutputParameter(3, 10)  # DoFs, maximum number of intermediate waypoints for memory allocation
 
    inp.current_position = [0.8, 0, 0.5]
    inp.current_velocity = [0, 0, 0]
    inp.current_acceleration = [0, 0, 0]
 
    inp.intermediate_positions = [
        [1.4, -1.6, 1.0],
        [-0.6, -0.5, 0.4],
        [-0.4, -0.35, 0.0],
        [-0.2, 0.35, -0.1],
        [0.2, 0.5, -0.1],
        [0.8, 1.8, -0.1]
    ]
 
    inp.target_position = [0.5, 1.2, 0]
    inp.target_velocity = [0, 0, 0]
    inp.target_acceleration = [0, 0, 0]
 
    inp.max_velocity = [3, 2, 2]
    inp.max_acceleration = [6, 4, 4]
    inp.max_jerk = [16, 10, 20]
 
    # Define a minimum duration per section of the trajectory (number waypoints + 1)
    inp.per_section_minimum_duration = [0, 2.0, 0.0, 1.0, 0.0, 2.0, 0]
 
 
    print('\t'.join(['t'] + [str(i) for i in range(otg.degrees_of_freedom)]))
 
    # Generate the trajectory within the control loop
    first_output, out_list = None, []
    res = Result.Working
    while res == Result.Working:
        res = otg.update(inp, out)
 
        print('\t'.join([f'{out.time:0.3f}'] + [f'{p:0.3f}' for p in out.new_position]))
        out_list.append(copy(out))
 
        out.pass_to_input(inp)
 
        if not first_output:
            first_output = copy(out)
 
    print(f'Calculation duration: {first_output.calculation_duration:0.1f} [µs]')
    print(f'Trajectory duration: {first_output.trajectory.duration:0.4f} [s]')
 
    # Plot the trajectory
    # path.insert(0, str(Path(__file__).parent.absolute().parent / 'test'))
    # from plotter import Plotter
 
    # Plotter.plot_trajectory(Path(__file__).parent.absolute() / '8_trajectory.pdf', otg, inp, out_list, plot_jerk=False)

Output Trajectory