目前，吉凯恩 (GKN) 公司正在位于德国的 Lohmar 研发中心内，开发一系列模块化控制算法，协助将动力系统软件集成至车辆的整体控制系统内。

具体来说，AWD 或电动传动系统的控制软件在各层的代码规模均达到了“兆字节”级别，而每辆车的整体软件代码规模也在急剧增加。GKN Lohmar 研发中心软件和电子系统经理 Michael Schomisch表示，与前代的2014 款相比，采用GKN技术的 2019 款 SUV 的软件代码规模将增加 10 倍。

Schomisch 表示，未来随着汽车系统的技术复杂度不断高速提升，如何保证各种车内系统的同步和协同工作，将成为一项愈发困难的挑战。为此，GKN集结了德国 Lohmar、美国 Auburn Hills 和上海研发中心的跨学科研发团队，共同打造了一种模块化算法技术。

GKN的专家团队将对系统进行物理建模，并以图形的方式创建将嵌入微处理器的控制算法。经过大量仿真和快速成型等早期验证流程后，GKN将在公司的冬季测试场，对 OEM客户的研发项目进行平台和整车测试。值得一提的是，公司的软件开发和集成团队自始至终全程参与了车辆的完整设计研发。

这一点非常关键，因为在很多项目中，GKN需要“对软件的开发和集成工作全权负责，”Schomisch 表示，“每个控制器均包含多层软件，内置基本操作系统、连接应用及电子促动器驱动等组成部分。”

简单来说，通用应用软件层将为车辆传动系统功能与其他电子系统之间的通信提供接口。Schomisch 表示，这些位于不同层的软件将协同工作，但各自具有“划分明确的责任领域”。

与以往一样，安全软件的重要性毋庸置疑，因为安全软件可以让硬件有能力自行处理一些指定参数之外故障或操作。功能应用软件则负责传动系统及其性能的具体控制。

实现多层控制

Schomisch 表示，最近的项目成果显示，通过应用模块化算法，传动系统的能量损失已经减少了 25% 左右，目前仅占动力系统总能量损失的 10%。很大程度上，这些进展均是通过对次级传动系统的精确控制而实现的。

例如，GKN的 Twinster 双离合器后轮驱动模块内置了一款汽车动力性能系统控制器，可以管理车辆的 AWD 需求、限滑性能、扭矩矢量控制（包括可以在福克斯 RS 的漂移模式下发挥更大作用的“超速偏移”功能），以及对车辆 ABS 和 ESC 系统的集成。目前，Twinster 的用户包括福特 Focus RS 及多款通用车型。

Twinster 双离合器后轮驱动模块由一款促动器控制器和一款车辆动力性能控制器实现控制。其中，促动器控制器负责管理双离合系统的驱动，从而实现非常高速的响应。此外，促动器离合器还负责监测、控制离合器温度、补偿离合器磨损、离合器开启幅度（以减少拖曳扭矩），并提供自我诊断功能。

Schomisch 表示，Twinster 模块内置的 5个独立软件包，可以配合目前已经登陆捷豹路虎 (Jaguar LandRover) 的后桥断开功能（axle disconnect），实现对先进 AWD系统的管理。后桥断开系统的促动器控制器可以管理爪形离合器，实现传动轴的断开和刹车功能。此外，该控制器还特别集成了连接反馈和自我诊断功能。

更上一层的控制器负责控制连接/断开序列的激活，最高一层的控制器则负责根据车辆的传感器数据输入，管理系统连接/断开的激活策略。

电动传动系统的新型控制器

GKN的 eDrive 系统还采用了一些更为复杂的软件。这家公司开发了一系列新型控制器，用以管理公司的先进电动传动系统，比如 BMW i8 采用的双速电子变速器。  

在 eDrive 系统结构中，传动系统的管理软件将在控制组件震动频率方面发挥至关重要的作用。否则，电动传动系统中的尖锐干扰共振噪声，将通过车辆结构件传入车舱，影响车上人员的安静乘车体验。

同样重要的是，GKN公司的传动系统管理软件还可以与其他车辆系统进行通信，从而让数据在系统控制策略中发挥更大作用。值得一提的是，GKN的 eDrive 系统还可以安全支持 OTA 升级。

At its Lohmar, Germany, R&D facility, GKN Driveline is creating modular control algorithms for new applications including integration of drivetrain software into a vehicle’s overall control system.

Control software for an AWD or electric driveline system demands more than a megabyte of code in multiple layers, while the sheer volume of software code per vehicle has increased dramatically. One 2019-model SUV using GKN technology will feature 10 times as much software code as its 2014 predecessor, according to Michael Schomisch, the Software and Electronics Manager at Lohmar.

He noted that with rapidly increasing technical complexity of vehicle systems comes "the increasingly challenging task of synchronizing the various systems to work together.” To do this, GKN's “unique” modular algorithm approach brings together multi-disciplinary teams from its Lohmar, Auburn Hills (USA) and Shanghai facilities.

The company’s specialist teams model the system’s physics and graphically create control algorithms to embed into a microprocessor. After simulation and rapid prototyping facilities provide early validation, GKN undertakes rig tests and vehicle integration activities on OEM development programs at its winter test sites. Software development and integration teams are fully incorporated into the vehicle engineering teams throughout this process.

This is crucial because for many programs GKN is "entirely responsible for the software development and integration," Schomisch said. "Each controller contains various layers of software. These include the basic operating system, connectivity applications, and the drivers for electronic actuators.”

A general-application software layer provides the interface between the driveline’s functions and other electric systems in the vehicle. These different layers of software interact but have "distinct areas of responsibility,” he said.

As always, safety software is paramount, enabling hardware to self-manage malfunctions or operations outside assigned parameters. Function applications software looks after specific control of the driveline systems and their performance.

Providing control on multiple levels

Driveline energy losses have been reduced by around 25% on recent programs, Schomisch said, and now account for only 10% of the total energy losses associated with transferring torque from the motor to the wheels. Much of this progress has been achieved through more precise control of the driveline subsystems.

For example, in GKN’s Twinster twin-clutch rear drive module that is fitted to the AWD Ford Focus RS and various GM vehicles, a vehicle dynamics controller manages the on-demand AWD, limited-slip and torque vectoring strategies (including the over-speed offset which, in the Focus RS, is exploited further with Drift mode), and the integration with the vehicle’s ABS and ESC systems.

The system is operated by an actuator controller and a vehicle dynamics controller. The actuator controller manages the twin-clutch actuation to achieve very fast response rates. It also monitors and adapts to clutch temperature, compensates for clutch wear, manages the wide clutch opening (to reduce drag torque) and delivers a self-diagnostic capability.

Five separate software packets manage the more advanced "hang-on" AWD system with axle disconnect used by Jaguar Land Rover, according to Schomisch. The disconnect system’s actuator controller manages the dog clutch, enabling the propshaft disconnect and brake function, which also incorporates connection feedback and self-diagnostics.

The next higher level controller controls the activation of the connect/disconnect sequence. The highest level controller manages the system’s strategy for activation of the connect/disconnect, based on data inputs from the vehicle’s sensors.

New controllers for electric drives

Even more complex software is used to control GKN's eDrive. A completely new range of controllers was developed to manage advanced electrified drivetrains, including the system in BMW’s i8 which has a 2-speed electronic transmission.

For this system, software within the driveline plays a vital role in managing the frequency levels emitted from the components; it would be unacceptable for vehicle occupants to be disturbed by a high-pitch whine resonating from the electric driveline through the vehicle structure.

Equally crucial is that the software developed to manage the driveline is able to communicate with other vehicle systems, so that data can be analyzed and acted on as part of the control strategies. It also has to securely accept over-the-air (OTA) updates.

Author: Stuart Birch
Source: SAE Automotive Engineering Magazine