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Distributed Functions: ICM and Actuator Control Units
The distribution of functions between the ICM and the other dynamic handling control units in the case of Integrated Active Steering is described below.
| Index | Explanation | ||
|---|---|---|---|
| 1 | Wheel speed sensors | ||
| 2 | Dynamic stability control | ||
| 3 | Steering column switch cluster with steering-angle sensor | ||
| 4 | Active Steering control unit | ||
| 5 | AS actuating unit | ||
| 6 | HSR control unit | ||
| 7 | HSR actuator unit | ||
| 8 | Integrated Chassis Management (ICM) | ||
| 9 | Other input and output signals(1) | ||
| 10 | Integrated DSC sensor (combined linear acceleration, lateral acceleration and yaw rate sensor) | ||
| 11 | Integrated DSC sensor (additional combined lateral acceleration and yaw rate sensor) | ||
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The Integrated Chassis Management is the control unit which computes the higher-level dynamic handling control functions for the Integrated Active Steering.
From the current vehicle handling status and the desired course indicated by the driver, the Integrated Chassis Management calculates individual settings for the variable steering- gear ratio and the superimposed yaw rate. Once they have been prioritized, the ICM provides a required setting in each case for the AL and HSR control units. The setting specified is a required steering angle to be applied to the front and rear wheels respectively.
The AL control unit receives the required setting and has the main job of controlling the actuators so as to correctly apply the specified setting. Thus the AL Active Steering control unit is purely an actuator control unit. The same applies to the HSR control unit. It too is an actuator control unit. Like the AL control unit, it is responsible only for implementing the required steering angle specified by the ICM.
With the introduction of the ICM on the E71, this type of function distribution was used for the first time. On the F01/F02, it has been expanded to the extent that
- the ICM now controls all linear and lateral dynamics systems (AL, HSR and also DSC) and
- the ICM is the master control unit both for linear dynamics and unstable handling situations.
The interface between the Integrated Chassis Management and the Dynamic Stability Control (DSC) represents a special case.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.