In recent years, a large variety of control subsystems for motor vehicles have been developed which assist the driver in different respects. A well-known type of control subsystem is an automatic brake control, which detects variations between rotating speeds of the wheels of a vehicle and controls braking force applied to the wheels so as to prevent these from slipping. Another prior art control subsystem known as ESP, electronic stability program, detects a steering wheel angle corresponding to a track curvature desired by the driver, compares it to an actual track curvature and, in case of a substantial discrepancy, brakes certain wheels in order to have the vehicle follow the desired track. Another control subsystem may adapt the damping efficiency of the vehicle suspension to the driving situation, so that, for example, the vehicle occupants may experience a feeling of cruising gently while driving at high speed on a smooth, straight lane, while providing a more direct feedback to the driver while driving, for example, off road.
In order to provide a comfortable driving experience, and, most of all, to enable safe driving, operating states of these various control subsystems must be adapted to each other. If instructions to switch over from one state to another are sent successively to the various subsystems, the subsystems may temporarily be in a combination of states which is ill-adapted to the current driving situation. In order to avoid such a situation, one might consider sending to each subsystem an instruction specifying not only the state which the subsystem is to assume but also a delay after which the changeover to the specified state is to happen, so that instructions may be sent to the subsystems one after the other, but once all instructions have been sent, the changeover can be carried out at the same time in all subsystems. However, for such a scheme to work, the delay must at least be long enough to allow instructions to be sent to each subsystem. Accordingly, there may be a considerable delay between the instant in which a new combination of states for the control subsystems is decided and the instant in which the control subsystems indeed switched over to the new states. This delay is the longer the higher the number of subsystems is, so that it is extremely difficult to integrate new subsystems on an existing platform. Further, the length of the delay must be known before the first instruction is transmitted to a subsystem.
At least one object of the present invention is, therefore, to provide a method and apparatus for jointly controlling a plurality of devices which allow to send instructions specific to each of the said devices simultaneously to all of these devices. In addition, other objects, desirable features, and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.