”ArkTwin: Distributed Heterogeneous Multi-Agent Simulation Platform”
received the Noguchi Award at DICOMO2024(Multimedia, Distributed,Cooperative, and Mobile Symposium).
InfoTech-AS
Social System PF Development Div.
Toyota Motor Corporation
Akira Yoshioka, Takatomo Torigoe, Naoki Akiyama
Toyota Motor Corporation is developing ArkTwin: distributed heterogeneous multi-agent
simulation platform that enables the simulation of a single world by allowing various
simulators to exchange necessary information and work together. At DICOMO2024(Multimedia, Distributed, Cooperative, and Mobile Symposium) organized by Information
Processing Society of Japan, a demonstration of ArkTwin was conducted, and it received thefirst-place Noguchi Award, an honor given to outstanding demonstrations expected tocontribute to the industry on June 28th.

Backgrounds
When considering the introduction of "new urban systems" such as smart cities, central urban
redevelopment, and new transportation services, the potential impacts can be extensive. If
stakeholders are concerned about increasing disadvantages from their respective perspectives,
it can make consensus-building difficult. While forming consensus through pilot projects isvaluable, it is difficult to implement so frequently because of the high costs involved.
Therefore, to conduct multiple impact assessments, it is necessary to use simulations torecreate reality in a virtual space.
To consider the wide-ranging impacts, it is necessary to simulate various elements within thesame space. However, constructing these as a single simulator is unrealistic for the following
reasons:l

The high difficulty of software implementationl

In cases such as service systems, where there is a competitive relationship, internal flows
may not be disclosedTherefore, it is expected that multiple heterogeneous simulators will collaborate byexchanging state information, including location, to achieve the simulation of a single world.

Technical Overview
Architecture Requirements
Below are the requirements that the platform must meet to enable the collaboration ofheterogeneous and multiple simulators.

・Utilization of Existing Simulators
To leverage existing, highly reliable simulators that are already widely used by many users, itis essential to connect them with minimal modification.

・Ease of execution for Various Types and Scales of Simulations
The types and number of simulators connected will vary depending on the simulationcontent, so flexible connectivity is required. Additionally, the platform must be capable ofconducting large-scale simulations that cover entire cities.

Proposed Architecture
The architecture proposed to meet the above requirements is shown in Figure 1.

Figure 1. The fundamental architecture

The architecture consists of the following two components:l

ArkTwin Center: A central unit that collects and distributes messages output by eachsimulator.
l

ArkTwin Edge: A unit that relays communications between a simulator and the ArkTwinCenter.
Each ArkTwin Edge is dedicated to one connected simulator.
To enable communication of information from each simulator, all ArkTwin Edge units areconnected to the ArkTwin Center. Any information that is not required by all simulators iscommunicated individually between the simulators themselves.
Figure 2 shows the communication details between a simulator and the ArkTwin Edge.

Figure 2. The communication between a simulator and ArkTwin Edge

ArkTwin Edge has the following functions in addition to controlling stream communication:

・Agent Registration
ArkTwin Edge registers the agents (individual vehicles, pedestrians, etc.) of the connected
simulator with ArkTwin Center and obtain a unique ID. This prevents ID collisions between
simulators.

・Coordinate Transformation
Each simulator may have different coordinate systems. Therefore, it normalizes thecoordinate systems of the connected simulator (origin, coordinate axis assignment, rotation
representation, etc.).

・State Acquisition of Other Simulator Agents
Each simulator is executed at individual time steps. Therefore, there is no guarantee that thestate information of agents at a specific time you want to simulate in your simulator will beavailable. To address this, it provides a function to interpolate state information received fromother simulators to the time step used in your simulator.

Demonstration
At DICOMO2024, we conducted a demonstration the interconnection of the following six
types of simulators:
1.

A simulator that simulates a single pedestrian operated by a demo participant using a VRdevice.

2.

A simulator that simulates a single wheelchair user operated by a demo participant usinga VR device.

3.

A simulator that simulates a single vehicle operated by a demo participant using asteering wheel controller.

4.

A traffic flow simulator that simulates multiple vehicles.

5.

A pedestrian flow simulator that simulates multiple pedestrians.

6.

A simulator that generates footage for fixed cameras.

Additionally, Figure 3 shows the configuration of the demonstration system.

Figure 3. The configuration of the demonstration system

The demonstration conductedOpen Sourcing of ArkTwin
ArkTwin is available as open-source software. It is released under the Apache License 2.0,
allowing for commercial use, modification, and distribution. We welcome any contributions,
whether it's using ArkTwin, reporting bugs, suggesting new features, or improving the code.
For detailed information and usage instructions regarding ArkTwin, please refer tohttps://github.com/arktwin/arktwin.