hpp-exec

ROS2 execution utilities for HPP-generated trajectories.

Overview

You write your HPP planning script using pyhpp directly, then use hpp_exec to send the trajectory to ros2_control.

Tutorials

The official tutorials for this package are in hpp_tutorial:

• Tutorial 6: Plan a simple arm motion and execute on Gazebo via send_trajectory()
• Tutorial 7: Pick-and-place with gripper actions using segments_from_graph() and execute_segments()

Creating configs and times from HPP

After planning and time parameterization with HPP, you have a Path object that maps time (seconds) to robot configurations. Sample it at regular intervals to get discrete waypoints:

import numpy as np

# After solving and time parameterization:
# p_timed = ps.getPath(pathId)  # or via path optimizer

n_samples = 50
configs = []
times = []

for i in range(n_samples + 1):
    t = (i / n_samples) * p_timed.length()
    q, success = p_timed(t)
    if success:
        configs.append(np.array(q))
        times.append(t)

# configs: List[np.ndarray] - configuration vectors at each waypoint
# times: List[float] - timestamps in seconds

The HPP configuration vector typically includes all robot DOFs. Use joint_indices to select which joints to send to ros2_control (e.g., arm joints only, excluding fingers).

Sending to ros2_control

from hpp_exec import send_trajectory

send_trajectory(
    configs, times,
    joint_names=["joint1", "joint2", ...],  # ROS2 joint names
    joint_indices=list(range(7)),            # Which HPP config indices to use
)

Installation

Docker (recommended)

cd hpp-exec
./run.sh

# First time inside container:
cd ~/devel/src && make all

API

from hpp_exec import send_trajectory, configs_to_joint_trajectory

# Main function - send trajectory to ros2_control
send_trajectory(
    configs,              # List[np.ndarray] from HPP
    times,                  # List[float] path parameter values
    joint_names,            # List[str] ROS2 joint names
    max_velocity=1.0,       # Rescale times to respect velocity limit
    max_acceleration=0.5,   # Rescale times to respect acceleration limit
    controller_topic="...", # FollowJointTrajectory action topic
)

# Lower-level conversion
trajectory = configs_to_joint_trajectory(configs, times, joint_names)

Examples

Examples use the FR3 robot in Gazebo simulation or real hardware.

# Terminal 1: Launch Gazebo with FR3
./run.sh
./hpp-exec/scripts/launch_gazebo_gripper.sh

# Terminal 2: Run example
docker exec -it hpp-exec bash
python3 ~/devel/hpp-exec/examples/simple_trajectory.py

See examples/README.md for all examples.

Structure

hpp-exec/
├── hpp_exec/           # Python package
│   ├── __init__.py
│   ├── trajectory_utils.py # HPP config → ROS2 JointTrajectory conversion
│   ├── ros2_sender.py     # send_trajectory() via FollowJointTrajectory action
│   └── gripper.py         # Gripper coordination for manipulation trajectories
├── examples/              # Usage examples (Gazebo + real hardware)
├── scripts/               # Launch scripts for Gazebo
├── robots/                # URDF/SRDF for examples
├── docs/                  # Architecture documentation
├── docker/
├── Dockerfile
└── run.sh

License

BSD-2-Clause