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-- lzb.lua
-- Enforced and/or automatic train override control, providing the on_train_approach callback
--[[
Documentation of train.lzb table
train.lzb = {
trav = Current index that the traverser has advanced so far
oncoming = table containing oncoming signals, in order of appearance on the path
{
pos = position of the point
idx = where this is on the path
spd = speed allowed to pass
fun = function(pos, id, train, index, speed, lzbdata)
-- Function that determines what to do on the train in the moment it drives over that point.
}
}
each step, for every item in "oncoming", we need to determine the location to start braking (+ some safety margin)
and, if we passed this point for at least one of the items, initiate brake.
When speed has dropped below, say 3, decrease the margin to zero, so that trains actually stop at the signal IP.
The spd variable and travsht need to be updated on every aspect change. it's probably best to reset everything when any aspect changes
]]
local params = {
BRAKE_SPACE = 10,
AWARE_ZONE = 50,
ADD_STAND = 2.5,
ADD_SLOW = 1.5,
ADD_FAST = 7,
ZONE_ROLL = 2,
ZONE_HOLD = 5, -- added on top of ZONE_ROLL
ZONE_VSLOW = 3, -- When speed is <2, still allow accelerating
DST_FACTOR = 1.5,
SHUNT_SPEED_MAX = advtrains.SHUNT_SPEED_MAX,
}
function advtrains.set_lzb_param(par, val)
if params[par] and tonumber(val) then
params[par] = tonumber(val)
else
error("Inexistant param or not a number")
end
end
local function look_ahead(id, train)
local acc = advtrains.get_acceleration(train, 1)
local vel = train.velocity
local brakedst = ( -(vel*vel) / (2*acc) ) * params.DST_FACTOR
local brake_i = advtrains.path_get_index_by_offset(train, train.index, brakedst + params.BRAKE_SPACE)
--local aware_i = advtrains.path_get_index_by_offset(train, brake_i, AWARE_ZONE)
local lzb = train.lzb
local trav = lzb.trav
--train.debug = lspd
while trav <= brake_i do
trav = trav + 1
local pos = advtrains.path_get(train, trav)
-- check offtrack
if trav > train.path_trk_f then
table.insert(lzb.oncoming, {
pos = pos,
idx = trav-1,
spd = 0,
})
else
-- run callbacks
-- Note: those callbacks are defined in trainlogic.lua for consistency with the other node callbacks
advtrains.tnc_call_approach_callback(pos, id, train, trav, lzb.data)
end
end
lzb.trav = trav
end
--[[
Distance needed to accelerate from v0 to v1 with constant acceleration a:
v1 - v0 a / v1 - v0 \ 2
s = v0 * ------- + - * | ------- |
a 2 \ a /
]]
local function apply_control(id, train)
local lzb = train.lzb
local i = 1
while i<=#lzb.oncoming do
if lzb.oncoming[i].idx < train.index then
local ent = lzb.oncoming[i]
if ent.fun then
ent.fun(ent.pos, id, train, ent.idx, ent.spd, lzb.data)
end
table.remove(lzb.oncoming, i)
else
i = i + 1
end
end
for i, it in ipairs(lzb.oncoming) do
local a = advtrains.get_acceleration(train, 1) --should be negative
local v0 = train.velocity
local v1 = it.spd
if v1 and v1 <= v0 then
local f = (v1-v0) / a
local s = v0*f + a*f*f/2
local st = s + params.ADD_SLOW
if v0 > 3 then
st = s + params.ADD_FAST
end
if v0<=0 then
st = s + params.ADD_STAND
end
local i = advtrains.path_get_index_by_offset(train, it.idx, -st)
--train.debug = dump({v0f=v0*f, aff=a*f*f,v0=v0, v1=v1, f=f, a=a, s=s, st=st, i=i, idx=train.index})
if i <= train.index then
-- Gotcha! Braking...
train.ctrl.lzb = 1
--train.debug = train.debug .. "BRAKE!!!"
return
end
i = advtrains.path_get_index_by_offset(train, i, -params.ZONE_ROLL)
if i <= train.index and v0>1 then
-- roll control
train.ctrl.lzb = 2
return
end
i = advtrains.path_get_index_by_offset(train, i, -params.ZONE_HOLD)
if i <= train.index and v0>1 then
-- hold speed
train.ctrl.lzb = 3
return
end
end
end
train.ctrl.lzb = nil
end
local function invalidate(train)
train.lzb = {
trav = atfloor(train.index),
data = {},
oncoming = {},
}
end
function advtrains.lzb_invalidate(train)
invalidate(train)
end
-- Add LZB control point
-- udata: User-defined additional data
function advtrains.lzb_add_checkpoint(train, index, speed, callback, udata)
local lzb = train.lzb
local pos = advtrains.path_get(train, index)
table.insert(lzb.oncoming, {
pos = pos,
idx = index,
spd = speed,
fun = callback,
data = udata,
})
end
advtrains.te_register_on_new_path(function(id, train)
invalidate(train)
look_ahead(id, train)
end)
advtrains.te_register_on_update(function(id, train)
if not train.path or not train.lzb then
atprint("LZB run: no path on train, skip step")
return
end
look_ahead(id, train)
apply_control(id, train)
end, true)
|
