1. An internal communication system adapted for communicatively coupling a plurality of nodes during a cycle, wherein the cycle presents a cycle length and a plurality of static temporal slots, and optimizing a schedule of time-triggered internodal messages and the cycle length, said system comprising:
at least one host electronic-control-unit (ECU); and
at least one channel communicatively interconnecting the nodes and ECU, said ECU and channel being cooperatively configured to transmit the messages to and from at least a portion of the nodes within the static slots, wherein each node is individually assigned to at least one slot, during the cycle, and a static segment, and number of unused slots is presented,
said ECU being programmably configured to autonomously determine an optimal schedule for transmitting the plurality of messages within the static slots, and an optimal cycle length, wherein the number of unused slots is maximized,
said ECU being further configured to fragment at least a portion of the messages into a plurality of signals prior to optimization, and defragment the signals, so as to reconstitute the original messages after optimization,
said ECU being further configured to determine for each signal (sij) an originating node, a size in bytes, a period in microseconds (Tij), and a transmission window, including start and end times (wsij, weij), such that 0\u2266wsij\u2266weij\u2266Tij, wherein i represents the node number and j represents the signal number.
2. The system as claimed in claim 1, wherein based on the transmission window wsij, weij of each signal (sij), a slot-cycle range (scr(ij)) for the signal is determined such that scr(ij)={(k, h)|1\u2266k\u2266gNumberOfStaticSlots, 1 \u2266h\u2266ncc, and (k, h) satisfies the following formulas:
(h\u22121)*gdCycle+(k\u22121)* LengthStaticSlot\u2267wsij, and
(h\u22121)*gdCycle+k* LengthStaticSlot\u2266weij.
3. The system as claimed in claim 2, wherein the slot-cycle assignment for each signal is encoded using integers 0 and 1, the number 1 indicates that signal (sij), is scheduled for the particular slot and cycle, and the sum of slot-cycle values for all combinations of differing nodal signals for any given slot is not greater than 1.
4. The system as claimed in claim 1, said ECU being further configured to determine a common period, T, equal to the least common multiple of a plurality of differing periods Tij.
5. The system as claimed in claim 4, said ECU being further configured to determine the length of the communication cycle in microseconds (gdCycle), the number of static slots in the static segment (gNumberOjStaticSlots), the payload length of a static frame for the static slot (gPayloadLengthStatic), the duration of a static slot in the number of macroticks (gdStaticSlot), the duration of a nominal macrotick in microseconds (gdMacrotick), and the duration of a static slot in microseconds (LengthStaticSlot), wherein the LengthStaticSlot is equal to the product of gdStaticSlot and gdMacrotick.
6. The system as claimed in claim 5, wherein the length of the communication cycle in microseconds (gdCycle) is a factor of the common period T.
7. The system as claimed in claim 5, wherein gPayloadLengthStatic, gdStaticSlot, and gdMacrotick are predetermined prior to receipt of the messages.
8. The system as claimed in claim 5, wherein optimal values for gdCycle, and gNumberOfStaticSlots are determined from a predetermined set of available combinations based on the period andor communication cycle length.
9. The system as claimed in claim 5, wherein the optimal schedule and cycle length are determined according to a plurality of requirements, including that each slot is assigned to at most one node, each signal is scheduled within its transmission window, and the total size of all signals that are assigned to the same slot in a communication cycle is less than or equal to the payload size of a static frame.
10. The system as claimed in claim 9, said schedule and cycle length being determined by modeling the system as a multiple choice integer program (MCIP) problem.
11. The system as claimed in claim 9, said ECU being further configured to terminate the determination of the optimal schedule and length for a given set of signals, when the requirements are not able to be met, and reinitiated upon receipt of a second plurality of messages.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A lumbar support for a vehicle backrest, the lumbar support comprising:
a rest member having a front surface shaped to support an area of a user’s back;
an elastic member comprising:
a) at least an attachment portion arranged behind said rest member and connected to an intermediate portion of said rest member, and
b) two opposing ends designed to be connected to a backrest frame;
said elastic member being designed to maintain said rest member in a rest position and to deform in response to a thrust of the user’s back so as to backwardly release said rest member:
between the rest position and a first position under normal use conditions, and
from the first position to a second position when a thrust against the front surface exceeds a given force value;
characterized in that the said elastic member has a characteristic forcedisplacement curve having a slope between zero and a given threshold in the section between the first and second positions; said threshold being equal to 0.5 Nmm.
2. The lumbar support according to claim 1, characterized in that the slope of said characteristic curve reaches zero in the section between the first and the second positions.
3. The lumbar support according to claim 1, characterized in that the shift between the first and second positions is at least equal to 20 mm.
4. The lumbar support according to claim 1, characterized in that the shift between the rest position and the first position is at least equal to 10 mm.
5. The lumbar support according to claim 1, characterized in that said elastic member is defined by a single spring.
6. The lumbar support according to claim 5, characterized in that said attachment portion is a straight horizontal portion having a length greater than or equal to 200 mm.
7. The lumbar support according to claim 5, characterized in that said single spring is a leaf spring.
8. The lumbar support according to claim 7, characterized in that said leaf spring has a height between 25 and 50 mm.
9. The lumbar support according to claim 7, characterized in that said leaf spring comprises two curved portions, which couple said attachment portion to said ends and each defining two bends having opposite concavities.
10. The support according to claim 9, characterized in that said bends have curvature radii between 20 and 50 mm.