PlatformHover#

A cooperative control task where a group of k UAVs are connected together by a rigid frame to form an overactuated platform. Each individual UAV, attached by a 2-DoF passive gimbal joint, acts as a thrust generator. The goal for the agents is to make the platform hover at a reference pose (position and attitude).

Observation#

The observation is a 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 frame center, and an one-hot identity indicating the UAV’s index.

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

  • obs_frame:

  • state_frame: (1, *): The state of the frame.

  • rpos (3): The relative position of the platform to the reference positions.

  • time_encoding (optional): The time encoding, which is a 4-dimensional vector encoding the current progress of the episode.

Reward#

  • reward_pose: The reward for the pose error between the platform and the reference (position and orientation).

  • reward_up: The reward for the alignment of the platform’s up vector and the reference up vector.

  • reward_spin: Reward computed from the spin of the drone to discourage spinning.

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

The total reward is computed as follows:

\[r = r_\text{pose} + r_\text{pose} * (r_\text{up} + r_\text{spin}) + r_\text{effort}\]

Config#

Parameter

Type

Default

Description

drone_model

str

“hummingbird”

num_drones

int

4

arm_length

float

0.85

reward_distance_scale

float

1.2

time_encoding

bool

True