Changelog#

This page lists the changes of the simulator by date. The repository has no numbered release yet.

The entries come from the commit history. The Learning section records the changes of the learning stack.

2026-10-02#

The documentation has a new structure, a new design and Simplified Technical English.
The generated reference includes the headers of ACRES Core and of the ROS 2 packages, the messages and an option index.

The scouting map products have margins for a learned driver.
The deployment program has a mission that drives to one field. Refer to Deployment.

ACRES Core: the simulator without Unreal, with a batch of environments, a ray-cast LiDAR and a Python module.
The package acres_core_sim: ACRES Core behind the sockets of the game, for ROS 2.
The package acres_sim: the ROS 2 bridge in C++ for the Polaris and the Maxxum.
The package acres_interfaces: the messages and services of the simulator.
The simulator control channel (-SimControl=): pause, lockstep steps, resets, entities, conditions and recording.
The episode log: an MCAP file with the agent states at the physics rate. The game and ACRES Core write the same format.
Episode replay (-EpisodeReplay=): the game shows an episode log from a different camera.
Render tiers that the game selects from the memory of the GPU, and a pinned sensor profile.
The timestamped command queue: a bridge command applies at the physics step that agrees with its arrival time.
Hardware shifts of the Polaris: biases of the speed sensor, the throttle, the brake and the steering.
Formal proofs of the drive-by-wire command path. Refer to Verification.
The lockstep barrier on the CAN bus (PGN 0xFF1E).

The ROS 2 package acres_ros became acres_sim and acres_description.
The Polaris chassis does not sleep in Chaos. A vehicle on a slope with released brakes now rolls.
The ULC speed loop operates along the engaged gear. A negative speed command in reverse gear drives backwards.
The energy ledger includes the chassis side in the game.
The west bin yard of field F50 is not field ground.

The project name changed from TERRA-AG to ACRES. Folder names became PascalCase.
The original buildings and bins are in their surveyed footprints.

The asset showcase, the structure tour and the legacy ground map.
The combine harvester of the game. Its source model stays in Acres/Raw/farm-equipment.
The tools that made the demonstration videos.

The Maxxum 150 as the tractor of the game, with eight implements and the implement model.
The soil library, the tyre and soil model and the fuel and energy model of the Maxxum.
The Polaris Ranger with its drive-by-wire model, fitted to the logs of the lab.
Sessions with more than one vehicle.
The first ROS 2 bridge and the closed-loop tests with the route follower of the lab.
The surveyed map in the game: surface polygons, the lane layer and the 2026 crops.
The data sources of the map and the error budget between the real farm and the simulator.
The calibration of the Polaris camera mount.
Weather and ground conditions from the Purdue Mesonet record.