BS ISO 20035:2019 pdf free

BS ISO 20035:2019 pdf free.Intelligent transport systems一Cooperative adaptive cruise control systems (CACC)
The CACC transition diagram in Figure 4 contains the same main ACC states described in ISO 15622,i.e. Off State, Stand-By State and Active State. The CACC active state has two main active states: the ACC Active state which is the same as the ACC active state in ISO 15622, and V2V Cooperative which represents the difference between the conventional ACC transition diagram in ISO 15622 and the CACC state transition diagram described in this document. This state is only reached when a valid connected vehicle data is received from a vehicle that is located in the CACC ROI defined in Figure 3. This V2V Cooperative state contains three child states: Non-Follow, Close-Follow and Follow mode states. The transition between these states depends on the existence of the TV, its connectivity, and also on the PVOI existence in the ROI.
If the communication with the TV is disconnected (its connected data is no more received by the subject vehicle) or the TV connected data is not valid data while the vehicle is in close follow mode and braking, the following shall happen: the CACC system continues braking, the CACC system goes to conventional ACC active mode, and the ACC active mode is enabled to use the 5 m/s2 maximum deceleration capabilities until braking is no more required and the gap becomes greater or equal than 0,8 s (minimum time gap in ACC).
If the communication with the TV is disconnected (its connected data is no more received by the subject vehicle) or the TV connected data is not valid data while the vehicle is in close follow mode and is not braking, the following shall happen: the CACC system goes to conventional ACC active mode, and the ACC active should avoid using hard braking to expand the gap back to the original ACC active setting if the relative velocity between the subject vehicle and host vehicle (Target Velocity- Host Velocity) is close to or above zero. This is in an attempt to reduce the possibility of string instability occurrence in the scenario when there are many CACC vehicles following each other and the communication is suddenly disrupted (for example: jammed).BS ISO 20035 pdf free download.