TransportHover

TransportHover#

A cooperative control task where a group of UAVs carry a box-shaped payload connected via rigid links. The goal for the agents is to make the payload hover at a reference pose (position and attitude).

Observation#

The observation space is specified a py:class:CompositeSpec containing the following items:

  • obs_self (1, *): The state of each UAV observed by itself, containing its kinematic information with the position being relative to the payload. It also includes a one-hot vector indicating each drone’s identity.

  • obs_others (k-1, *): The observed states of other agents.

  • obs_payload (1, *): The state of the frame, containing its position (relative to the reference), rotation (in quaternions and direction vectors), and velocities

Reward#

  • separation: A factor that penalizes all agents when the minimum separation is too small.

  • pos: Reward for hovering at the reference position, computed as :math:\exp(-a * \text{pos_error}).

  • up: Reward for keeping the payload upright.

  • swing: Reward for avoid large swinging of the payload.

  • joint_limit: Reward for keeping the joint states in a reasonable range to avoid glitchy behaviors.

  • effort: Reward computed from the effort of the drone to optimize the energy consumption.

\[r = r_\text{separation} * (r_\text{pos} + r_\text{pos} * (r_\text{up} + r_\text{swing}) + r_\text{joint\_limit})\]

Config#

Parameter

Type

Default

Description

drone_model

str

“hummingbird”

num_drones

int

4

safe_distance

float

0.5

A threshold value that gives penalty when the minimum separation between the UAVs is too small.

mass_scale

List[float, float]

[0.5, 0.8]

A tuple of two values that specifies the range of the payload mass to sample from in each episode (as ratio to the drone’s mass).
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