Control system could improve the agility of hybrid vehicles

The system is reported to deliver improvements without compromising requirements for low emissions, safety and driver feedback.

It is said to increase the agility, stability and manoeuvrability of hybrid vehicles, while also allowing them to perform ‘controlled drifts’. The developers claim that the system is energy efficient and unobtrusive, which means the benefits do not put any additional strain on the battery or deliver any negative feedback effects to the driver.

Lorenzo Pinto, a simulation specialist at MIRA, told The Engineer: ‘A concept was initially developed using simulation tools and once we had a clear idea of what features we could achieve, we transferred the control logic onto the prototype and started the validation and refinement phase.’

The prototype vehicle was MIRA’s Hybrid 4-Wheel Drive Vehicle (H4V), a series/parallel hybrid retrofit to a 1.4-litre Skoda Fabia. Pinto explained how the system has been proven on this vehicle despite the fact it was not designed specifically with EDC in mind, both in terms of the powertrain and the chassis.

‘In the end we didn’t have any significant failures during the development, which stands as another proof of how compatible the system is with current technology,’ he said.

In an EPSRC-funded project, researchers at Brunel University are looking at what they say are novel opportunities provided by EDC to enlarge the safety envelope of the vehicle.

The Brunel team is specifically looking at how control algorithms can play a role in active limit handling. It is aiming to use the control authority (introduced by current active safety systems and modern power/drivetrain configurations) to actively assist the driver.

The overall aim is to help the driver exploit the limits of the vehicle’s handling during emergency manoeuvring.

Efstathios Velenis, principal investigator at Brunel, said: ‘We are hoping to find out if there is any benefit in terms of safety when we allow the vehicle to reach the limit in a safe manner.

‘If the driver applies a very sudden steering command, we may want the system to allow the vehicle to oversteer to enter an unstable condition. However, the additional control we have on the four wheels may apply some corrective inputs in order to maintain stability near such limit conditions,’ commented Velenis. 

‘So far, I’ve been attempting to mathematically model driving techniques used by racing drivers,’ he said.