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ROSBuzz_MISTLab
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adapted sync algo to robots

This commit is contained in:
vivek-shankar 2018-07-11 23:19:51 -04:00
parent 9f75bd989e
commit 7ab97b4fce
2 changed files with 47 additions and 40 deletions
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2
buzz_scripts/include/act/barrier.bzz
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@ -67,7 +67,7 @@ function barrier_wait(threshold, transf, resumef, bc) {
barrier = nil
timeW = 0
BVMSTATE = resumef
} else if(timeW % 10 == 0 and bc > 0)
} else if(timeW % 50 == 0 and bc > 0)
neighbors.broadcast("cmd", bc)
timeW = timeW+1

85
buzz_scripts/include/timesync.bzz
View File

@ -5,7 +5,8 @@ logical_time = 0
# sync algo. constants
TIME_JUMP_THR = 5
TIME_TO_FORGET = 20
TIME_TO_SYNC = 100
TIME_TO_SYNC = 200
COM_DELAY = 3
# table to store neighbor time data
time_nei_table = {}
# Algo. global parameters
@ -18,20 +19,23 @@ sync_timer = 0
function init_time_sync(){
neighbors.listen("time_sync",
function(vid, value, rid) {
log(" TIME SYNC Got (", vid, ",", value, ") #", rid)
var msg = string.split(value,",")
var msg_time = string.toint(msg[0])
var msg_max = string.toint(msg[1])
#log("msg: 1: ", msg_time, " 2: ", msg_max )
diffMaxLogical = math.max(diffMaxLogical,msg_max-logical_time)
var time_offset = msg_time - logical_time
if(math.abs(time_offset) > math.abs(syncError)) syncError = time_offset
if(time_offset > TIME_JUMP_THR){
logical_time = logical_time + time_offset
diffMaxLogical = math.max(diffMaxLogical-time_offset,0)
jumped = 1
if(value != nil){
log(" TIME SYNC Got (", vid, ",", value.time , " , ", value.max, ") #", rid)
var msg_time = value.time
var msg_max = value.max
#log("msg: 1: ", msg_time, " 2: ", msg_max )
if(msg_time != nil and msg_max != nil){
diffMaxLogical = math.max(diffMaxLogical,msg_max-logical_time)
var time_offset = msg_time - logical_time
if(math.abs(time_offset) > math.abs(syncError)) syncError = time_offset
if(time_offset > TIME_JUMP_THR){
logical_time = logical_time + time_offset
diffMaxLogical = math.max(diffMaxLogical-time_offset,0)
jumped = 1
}
time_nei_table[rid] = { .time=msg_time, .age=0, .max=msg_max}
}
}
time_nei_table[rid] = { .time=msg_time, .age=0, .max=msg_max}
}
)
}
@ -44,36 +48,39 @@ function step_time_sync(){
log(" SYNC ALGO ACTIVE time:", sync_timer)
cnt = 0
avg_offset = 0
foreach(time_nei_table, function(key, value) {
if(value != nil){
#log("ForEach neigh : id ", key, " time ", value.time, " , age ", value.age, " , diffmax ", value.max)
var local_offset = value.time - logical_time - value.age
if(local_offset > 0){
avg_offset = avg_offset + 1 * local_offset
cnt = cnt + 1
}
else{
if(math.abs(local_offset)<TIME_JUMP_THR){
avg_offset = avg_offset + local_offset
cnt = cnt + 1
}
}
if(size(time_nei_table) > 0){
foreach(time_nei_table, function(key, value) {
if(value.time != 0){
#log("ForEach neigh : id ", key, " time ", value.time, " , age ", value.age, " , diffmax ", value.max)
var local_offset = value.time - logical_time - value.age
if(local_offset > 0){
avg_offset = avg_offset + 1 * local_offset
cnt = cnt + 1
}
else{
if(math.abs(local_offset)<TIME_JUMP_THR){
avg_offset = avg_offset + local_offset
cnt = cnt + 1
}
}
if(value.age > TIME_TO_FORGET)
time_nei_table[key] = nil
value.age = value.age + 1
if(value.age > TIME_TO_FORGET)
value.time = 0
value.age = value.age + 1
}
})
if(cnt > 0 and jumped != 1){
var correction = math.ceil(avg_offset / (cnt + 1) )
if(math.abs(correction) < TIME_JUMP_THR){
logical_time = logical_time + correction
}
}
})
if(cnt > 0 and jumped != 1){
var correction = math.ceil(avg_offset / (cnt + 1) )
if(math.abs(correction) < TIME_JUMP_THR){
logical_time = logical_time + correction
}
}
jumped = 0
syncError=0
var mstr = string.concat(string.tostring(logical_time + 1),",",string.tostring(logical_time + 1 + diffMaxLogical))
var mstr = {.time = (logical_time + COM_DELAY) , .max = (logical_time + COM_DELAY + diffMaxLogical) }
#string.concat(string.tostring(logical_time + 1),",",string.tostring(logical_time + 1 + diffMaxLogical))
neighbors.broadcast("time_sync",mstr)
}
log("Logical time now ", logical_time)