Boiler Drum

Boiler drum — natural-circulation drum boiler with shrink-and-swell.

Action space	Box((2,)), all actions in [-1, 1]
Observation space	Box((7,))
Tracked variable(s)	drum level (m), drum pressure (bar)
Episode length	400 steps (800 s at 2 s per step)
Import	from target_gym import BoilerDrum, BoilerDrumParams
Cite as	boiler_drum-v1

Action space

Actions are normalised to [-1, 1] and mapped onto the plant's real actuator range inside the environment.

#	meaning	min	max
0	fuel	-1	1
1	feedwater	-1	1

Observation space

7 values. Indices (0, 1) carry the tracked variable(s) that the reward scores.

Rewards

Level and pressure tracking, minus fuel.

Every environment in this suite scores on one contract: the reward is (tracking terms, multiplied) x (1 - weighted costs), bounded in [0, 1], and reaches 1 only while the target is held exactly. See Reward shaping.

Starting state

reset samples the initial condition and the target; state has 11 fields.

Episode end

Termination. High level carries water to the turbine; low level uncovers the tubes.

Truncation. After 400 steps.

Baselines

A tuned PID ships with this environment.

Arguments

parameter	default
delta_t	2
max_steps_in_episode	400
V_t	88
V_d	40
V_r	37
V_dc	11
A_d	20
A_dc	0.355
L_r	11
m_metal	300000
C_metal	550
k_friction	25
tau_sr	8
T_d	15
…	20 more, see the params dataclass