Development of an active trailer differential braking system for car-trailer combinations

该项目的目标是开发一个概念设计的主动拖车差速制动(ATDB)系统的汽车-拖车组合。尽管电子稳定控制(ESC)系统增加了安全性，但几乎所有这些设备都是为单单元车辆设计的，没有考虑拖车等外部负载。汽车拖车组合由于其复杂的结构，在高速下表现出降低的稳定性。与单车相比，车-挂车组合表现出独特的不稳定运动模式，包括千斤顶切割、挂车摆动和侧翻。这些不稳定的运动模式是高速公路上发生事故的常见原因。到目前为止，大多数挂车都使用被动机构来提高其在高速下的稳定性。不幸的是，拖车系统的高速稳定性不能 由于运行条件变化很大，如挂车有效载荷、前进速度、路况等的变化，因此采用了被动机制。为了提高汽车-拖车组合的性能，加拿大通用汽车有限公司(GM)正在为车辆系统研究新的主动安全系统。凭借UOIT团队的专业知识，主动安全系统将使用创新的ATDB技术进行设计，该技术建立在ESC针对单单元车辆的现有技术基础上。与通用汽车的工程师合作，UOIT团队将：1)进行数值模拟，以检查典型的通用乘用车在拖曳传统拖车时，在安装和不安装嵌入式ESC系统时的方向性能；以及2)进行ATDB系统的概念设计，并通过数值模拟评估安全装置的有效性。研究项目将为ATDB系统设计解决以下问题：1) 找到有效的方法来确定启动ATDB系统的阈值；2)确定有效的控制策略，以防止千斤顶切割不稳定的运动模式；以及3)确定汽车上嵌入的现有ESC系统对所产生的汽车拖车系统在拖车时的稳定性的影响。该创新性研究将为下一步研制物理ATDB样机奠定坚实的基础。

The objective of the project is to develop a conceptual design of active trailer differential braking (ATDB) systems for car-trailer combinations. Despite the safety increases provided by electronic stability control (ESC) systems, nearly all these devices are designed for single-unit vehicles and take no account of external loads, such as trailers. Car-trailer combinations exhibit reduced stability at high speeds due to their complex configurations. Compared with single-unit vehicles, car-trailer combinations show unique unstable motion modes, including jack-knifing, trailer swing, and roll-over. These unstable motion modes are the common causes for accidents occurring on highways. To date, the majority of trailers use passive mechanisms to enhance their stability at high speeds. Unfortunately, the high-speed stability of a car-trailer system cannot be guaranteed with a passive mechanism, because operating conditions vary significantly, such as the variation of trailer payload, forward speed, road conditions, etc. To enhance the performance of car-trailer combinations, General Motors of Canada Limited (GM) is researching new active safety systems for the vehicle systems. With expertise from the UOIT team, the active safety system will be designed using an innovative ATDB technique, which is built upon existing technologies of ESC for single-unit vehicles. Collaborating with the GM engineers, the UOIT team will: 1) perform numerical simulations to examine the direction performance of a typical GM passenger car with and without an embedded ESC system when it tows a conventional trailer; and 2) conduct a conceptual design of an ATDB system and evaluate the effectiveness of the safety device by numerical simulations. The research project will address the following issues for the ATDB system design: 1) finding effective ways to determine the threshold limit to actuate the ATDB system; 2) determining effective control strategies to prevent jack-knifing unstable motion mode; and 3) identifying the effects of existing ESC system embedded on a car on the stability of the resulting car-trailer system when the car is towing. The innovative research will lay a solid foundation to fabricate physical ATDB prototypes in the next project.