TEST & SAFETY SYSTEMS


With record-high fuel prices and


government incentives for low- emission vehicles, the consumer adoption of electric vehicles has accelerated, reaching an 8% share of new European vehicle registrations, according to a recent study by McKinsey. The pressure to develop new vehicle platforms, together with the increasing complexity of vehicle systems such as advanced driver assistance systems (ADAS), makes OEMs look at alternative methods to be able to increase their development pace and capacity, shortening the time to market. One way to achieve higher development efficiency is to use the concept of vehicle-in-the-loop (ViL) testing, a method that OEMs and Tier 1s are adopting to a greater extent. The company Rototest has been


supplying solutions for vehicle-in- the-loop for many years. In Rototest’s case, the object that is put in-the-loop can be anything, such as part of a powertrain, a prototype vehicle or a production vehicle. While the focus in the early days was on durability and track simulations, the main focus today tends to be more advanced configurations, including the full ADAS architecture of the vehicle. This architecture can generally be


described as being composed of three subsystems: the perception system, the decision system and the actuation system. The perception system is responsible for monitoring the surroundings of the vehicle and can include anything from a single camera to multiple cameras, short-range and long-range radars, ultrasonic sensors and LIDARs, etc. Depending on specific architecture, the perception system may also include the functionality of sensor fusion, meaning that the perception system takes information from multiple sensors and fuses it together to supply the next system in the chain – the decision system –


A vehicle-in-the-loop system based on Rototest’s platform


with better information. An example could be a camera that detects an object in view. Together with a radar that determines the distance to the object, the information could be fused together and provided to the decision system. The decision system does exactly


what you’d expect – it makes decisions. Should we warn the driver of the object in front? Should we apply the brakes as we are approaching too quickly? Should we apply steering to keep the vehicle in the lane? These are typical decisions for the


system to make and then provide the actuation system with the appropriate task for action. The actuation system executes the decision that has been decided. A simplified comparison of the ADAS architecture with a human driver would be that the perception system would be the eyes, the decision system the brain, and the actuation system the muscles operating the accelerator, brake pedal and steering wheel. A typical vehicle-in-the-loop


configuration for ADAS applications built upon Rototest’s technology and an open platform would in general include Rototest’s high-


dynamic powertrain dynamometer, a simulation environment of choice and a stimuli system such as over- the-air simulators or bus-injection, depending on access. The simulation environment is responsible for simulating the vehicle’s surroundings, i.e., what the vehicle would ‘see’ if it was driven on the road. This means that the simulation environment feeds the stimuli system with information of how the vehicle is travelling in the simulated environment and how it is interacting with other objects such as other vehicles or vulnerable road users. The dynamometer’s responsibility lies in providing the correct response and load back to the vehicle’s powertrain so that it represents actual road driving. The main benefit of Rototest’s


vehicle-in-the-loop platform is that the decision and actuation systems can be fully tested, optimised and, thanks to the truly road-like behaviour of Rototest’s dynamometer, calibrated before bringing the vehicle to a test track – thereby enabling a huge time-saving potential. This, as in the controlled environment of the lab, means that precise repetitions of complex manoeuvres can be made repeatedly without losing time repositioning the test vehicle and test objects on the track. And, naturally, weather is not a concern in a vehicle- in-the-loop scenario as any weather can be simulated, allowing you to decide if and when you want rain. ●


General ADAS architecture with three subsystems


See www.rototest.com for more information


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