Intelligent Vehicle Dynamics and Controls – Q&A with Professor Xinjie Zhang



June 2020


The answers below are from Professor Xinjie Zhang, State Key Laboratory of Automotive Simulation and Control at Jilin University in China, who gave a presentation on Cooperative Adaptive Cruise Control (CACC) including Platoon Kinematics.

What is the time headway for the CTH policy in this talk? Is it a constant?

The idea of the proposed integrated spacing policy is to use the safety redundancies of the Constant time headway (CTH) and Safety distance (SD) spacing policies, and the critical speed Vc is depended on the max deceleration, time headway and brake response time. It works for variable time headway.

Could you talk about the benefits of including platoon kinematics?

For improve traffic efficiency and energy consumption reducing, the main solutions, from down to top, are single vehicle eco-drive, platoon optimisation and smart traffic.

In this talk, we tried to improve traffic efficiency from spacing policy and cooperative control strategy. We used the safety redundancies between Constant time headway (CTH) and Safety distance (SD) spacing policies, and utilised platoon kinematics to make the host vehicle respond more adaptively and comfortably, to satisfy the human driver operation habits, reduce the platoon vehicle response delay accumulation, and improve ride comfort, safety and traffic efficiency.

In the future, for eco-drive and advanced safety, we will give a solution via the trinity of advanced mobility performance, platoon optimisation, and smart traffic planning. And the multiple automated vehicles coordinating will be a good solution.

In the event that the adhesion coefficient changes, from a dry road to an icy road for example, does the vehicle's personalised intelligent system take this into account?

The adhesion coefficient is a core parameter for vehicle dynamics and control. It is the upper boundary of vehicle acceleration and deceleration, and have major influence on vehicle following control, such as spacing policy, upper control strategy for desired acceleration allocation and lower tracking control.

In this talk, the host vehicle and whole platoon are on a road with same adhesion coefficient. In other word, for a dry road or an icy road is ok right now, and the μ-jump road will be included in the future while the safety is the first.

The scenarios reconstruction is an interesting topic, could you show the details?

Scenarios reconstruction is a big topic. Scenarios is a key point for intelligent vehicle design and validation. We all try our best to cover all cases with as few scenarios as we can. In this talk, the simulation tests focus on vehicle following performance under urban cases.

Scenarios are reduced via three-layer decompositions. In level 1, the disturbance sources are divided into two categories, from current platoon and out of platoon. In level 2, 5 typical disturbances are cascaded from both inside and outside of platoon. And in level 3, 8 scenarios are reconstructed.

For CACC and V2X presentation, congratulation, what are the next steps for traffic monitoring taking advantage of V2X?

Transportation and mobility innovation are happening at an unprecedented pace. The human-vehicle-traffic is a whole ecosystem. For eco-driver and advanced safety, the main solutions, from down to top, are single vehicle eco-drive, platoon optimisation and smart traffic and smart city.

The more valuable communication via V2X, the decision and planning will be optimised better. The V2X will help to promoting the human-vehicle-traffic system’s human-vehicle-traffic intellectualisation, humanisation and personalisation, such as smart traffic planning, platoon optimisation, platoon length optimisation, pilot route planning, humanised and personalised eco-drive.

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Vehicle Dynamics and Controls will continue to evolve as we move ever closer to fully automated driving. This area is just one being considered as part of Intelligent Safety. If you wish to learn more about the subject and continue the conversation, the Intelligent Safety Conference will be held in conjunction with the China SAE Congress & Exhibition (SAECCE), in October 2020, in Shanghai. Please visit the FISITA website for more information.