Client: RIPAS (Разработка и производство автоматизированных систем, Automated Systems Design and Manufacture) Brief: Integrate Aimsun microsimulation and SPEKTR traffic controllers and traffic management system (developed by RIPAS) to allow on-the-spot projection of adaptive controls onto real-life networks.
In answer to the high demand for network development in Russia, RIPAS has developed a tool that can clearly demonstrate future possibilities to traffic engineers and potential investors and developers: the PIC Program Interface Controller. The PIC is a kind of visionary tool that links Aimsun modelling software with the SPEKTR road traffic controller and the ITS SPEKTR (the control centre).
PIC is an internal development at RIPAS and is currently not externally marketed but used principally as a training tool in universities, to test and adapt models and also for promotional purposes, to show what the SPEKTR controllers and Aimsun are capable of. The interface between the software and the controller means that hardware and software modelling is carried out in real time. This simulation allows the specialist to fine-tune adaptive algorithms using the real controller, setting the position of transport detectors, duration of phases and other parameters. Through this link, practitioners can carry out tests of the RTC in real modes from their office desk.
Modelled intersection with real TLC connected
The technical team at RIPAS wrote a software module for Aimsun and developed a hardware module for the TLC (traffic light controller). Aimsun is connected to the SPEKTR TLC via the USB RS232 engineering control interface for detector data transmission. The controller is also connected to the PC via RS232 to read the state of the TLC signal group along with other parameters, and is connected via Ethernet to the control centre.
When the vehicles in the Aimsun simulated street network interact with the transport detector in the model using PIC, this signal transmits to the TLC detector board. The TLC believes that it is triggered by physical detectors and the state of the current signal group and the results of processing are sent back into Aimsun.
The controller works on the same time-scale as the Aimsun model: switch the time range and the controller will switch to the same one; stop the model and the controller’s clock will stop too. Similarly, switching the controller’s settings in the control centre effects the same changes in the Aimsun model. It is as close as it gets to the real environment.
PIC is a useful training platform as it allows operators to explore all the features of traffic control with simulated vehicles. Students use PIC for free at the Saint-Petersburg State University of Architecture and Civil Engineering to carry out studies, test algorithms and perform test runs with controllers. PIC is also useful for establishing coordination plans which is sometimes difficult in adaptive mode. PIC allows the user to coordinate the plans, which will be tested and refined before use in the real world.
A number of companies and research institutes are developing advanced adaptive control algorithms. The integration of SPEKTR and Aimsun allows project developers to test the effectiveness of current algorithms and compare them with more innovative algorithmic pilots. This integration exemplifies what Aimsun is all about: openness and possibility.