Blocked Unlock Pickup

Action Space	Discrete(7)
Observation Space	Dict('direction': Discrete(4), 'image': Box(0, 255, (7, 7, 3), uint8), 'mission': MissionSpace(<function BlockedUnlockPickupEnv._gen_mission at 0x7f813f519ca0>, [['blue', 'green', 'grey', 'purple', 'red', 'yellow'], ['box', 'key']]))
Reward Range	(0, 1)
Creation	gymnasium.make("MiniGrid-BlockedUnlockPickup-v0")

Description

The agent has to pick up a box which is placed in another room, behind a locked door. The door is also blocked by a ball which the agent has to move before it can unlock the door. Hence, the agent has to learn to move the ball, pick up the key, open the door and pick up the object in the other room. This environment can be solved without relying on language.

Mission Space

“pick up the {color} {type}”

{color} is the color of the box. Can be “red”, “green”, “blue”, “purple”, “yellow” or “grey”.

{type} is the type of the object. Can be “box” or “key”.

Action Space

Num	Name	Action
0	left	Turn left
1	right	Turn right
2	forward	Move forward
3	pickup	Pick up an object
4	drop	Unused
5	toggle	Unused
6	done	Unused

Observation Encoding

• Each tile is encoded as a 3 dimensional tuple: (OBJECT_IDX, COLOR_IDX, STATE)

• OBJECT_TO_IDX and COLOR_TO_IDX mapping can be found in minigrid/core/constants.py

• STATE refers to the door state with 0=open, 1=closed and 2=locked

Rewards

A reward of ‘1 - 0.9 * (step_count / max_steps)’ is given for success, and ‘0’ for failure.

Termination

The episode ends if any one of the following conditions is met:

1. The agent picks up the correct box.

2. Timeout (see max_steps).

Registered Configurations

• MiniGrid-BlockedUnlockPickup-v0