Shifting Strategy in Autonomie
Shifting Strategy in Autonomie
THIS PRESENTATION DISCLOSES MATERIAL PROTECTED UNDER COPYRIGHT LAW AND FURTHER DISSEMINATION IS PROHIBITED WITHOUT PRIOR
WRITTEN CONSENT OF THE PATENT COUNSEL OF ARGONNE NATIONAL LABORATORY
© COPYRIGHT March 2009 UChicago Argonne, LLCALL RIGHTS RESERVED
2© COPYRIGHT March 2009 UChicago Argonne, LLC
Shifting Maps
3
Shifting Strategy Is Based on Shift Maps
4
0 10 20 30 40 50 600
0.2
0.4
0.6
0.8
1
Speed (m/s)
Accel. P
edal
Upshift 12
Downshift 21
Upshift 23
Downshift 32
Upshift 34
Downshift 43
Upshift 45
Downshift 54
𝑎𝑝𝑒𝑟𝑓
𝑎𝑒𝑐𝑜𝑑𝑛
𝑎𝑒𝑐𝑜𝑢𝑝
𝑉𝑒𝑐𝑜𝑑𝑛 𝑉𝑒𝑐𝑜
𝑢𝑝
𝑉𝑝𝑒𝑟𝑓𝑢𝑝𝑉𝑝𝑒𝑟𝑓
𝑑𝑛
Δ𝑉𝑒𝑐𝑜
Δ𝑉𝑝𝑒𝑟𝑓
Upshifting
Downshifting
Shifting maps for default Autonomie Vehicle
Upshifting/Downshifting curves for one gear
Upshifting occurs when (a,V) goes from the left side of the upshifting curve to the right side
Downshifting occurs when (a,V) goes from the right side of the downshifting curve to the left side
Depends on vehicle
Constants
Shifting happens when the couple (acceleration,vehicle speed) [(a,V)] crosses a shifting curve
“Eco-Driving” Shifting Speeds
Up and downshifting vehicle speed in very smooth driving conditions (a=0)
5
𝑉𝑒𝑐𝑜𝑑𝑛 𝑉𝑒𝑐𝑜
𝑢𝑝
Upshifting
Downshifting
Acc
el. P
edal
Po
siti
on
Vehicle Speed
“Eco-Driving” Shifting Speeds Are Based on Engine
Map and Gear Ratios
6
500 1000 1500 2000 2500 3000 35000
1
2
3
4
5
6
engine speed [rpm]
Engine speed operating range (acc=0) for each gear
1st gear
2nd gear
3rd gear
4th gear
5th gear
𝜔𝑒𝑐𝑜2→1: Idle Speed
𝜔𝑒𝑐𝑜2→1=𝜔𝑖𝑑𝑙𝑒 𝑞𝑖𝑑𝑙𝑒
𝜔𝑒𝑐𝑜2→3
𝜔𝑒𝑐𝑜3→4
𝜔𝑒𝑐𝑜𝑁−1→𝑁 (𝜔𝑒𝑐𝑜
4→5):
Best efficiency speed
𝜔𝑒𝑐𝑜1→2:
Idle speed x ratio of ratios
𝜔𝑒𝑐𝑜1→2 = 𝜔𝑖𝑑𝑙𝑒
𝑘1𝑘2
1 + 𝜖𝑢𝑑
𝜔𝑒𝑐𝑜3→2
𝜔𝑒𝑐𝑜4→3
𝜔𝑒𝑐𝑜𝑁→𝑁−1 (𝜔𝑒𝑐𝑜
5→4): - 100 rad/s
𝜔𝑒𝑐𝑜𝑁→𝑁−1 = 𝜔𝑒𝑐𝑜
𝑁−1→𝑁 − 𝜔Δ
Engine Speed (RPM)
Gear
𝜔𝑖𝑑𝑙𝑒: idle speed // k1,k2: gear ratios for gears 1,2 // 𝜖𝑢𝑑: Margin to avoid overlap // 𝜔Δ ≈ 1000 RPM // 𝑞𝑖𝑑𝑙𝑒 : idle ratio (1.1)
To avoid overlap, we verify that 𝜔𝑒𝑐𝑜𝑖→𝑖+1 > 𝜔𝑒𝑐𝑜
𝑖+1→𝑖 ∙𝑘1
𝑘21 + 𝜖𝑢𝑑 , 1 ≤ 𝑖 ≤ 𝑁 − 1
“Performance” Upshifting Speeds
7
0 20 40 60 800
500
1000
1500
2000
2500
3000
3500
Speed (m/s)
Torq
ue @
Whl (N
m)
Gear 1
Gear 2
Gear 3
Gear 4
Gear 5
𝑉𝑝𝑒𝑟𝑓1→2 𝑉𝑝𝑒𝑟𝑓
2→3𝑉𝑝𝑒𝑟𝑓3→4 𝑉𝑝𝑒𝑟𝑓
4→5
• Performance shifting ensures maximum torque output at the wheels • Computed by algorithm (often, but not always, engine top speed)
“Performance” Shifting Speeds
Up and downshifting vehicle speeds “pedal to the metal” (a=1)
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Upshifting
Downshifting
𝑉𝑝𝑒𝑟𝑓𝑢𝑝𝑉𝑝𝑒𝑟𝑓
𝑑𝑛
Acc
el. P
edal
Po
siti
on
Vehicle Speed
“Performance” Downshifting Speeds
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𝑎𝑝𝑒𝑟𝑓
𝑎𝑒𝑐𝑜𝑑𝑛
𝑎𝑒𝑐𝑜𝑢𝑝
𝑉𝑒𝑐𝑜𝑑𝑛 𝑉𝑒𝑐𝑜
𝑢𝑝
𝑉𝑝𝑒𝑟𝑓𝑢𝑝𝑉𝑝𝑒𝑟𝑓
𝑑𝑛
Δ𝑉𝑒𝑐𝑜
Δ𝑉𝑝𝑒𝑟𝑓
Upshifting
Downshifting
• The difference between an upshifting and a downshifting curve is twice as big on the top (Δ𝑉𝑝𝑒𝑟𝑓) as at the bottom (Δ𝑉𝑒𝑐𝑜)
• Follows this equation with 𝛼𝑝𝑓,𝑒𝑐 = 2 :
Δ𝑉𝑝𝑒𝑟𝑓𝑖 = 𝛼𝑝𝑓,𝑒𝑐 ∙ Δ𝑉𝑒𝑐𝑜
𝑖
Shifting Logic
10
Shifting Logic (Schematic)
11
𝒂(𝒕)
𝑽(𝒕)
Upshifting Table
𝜸𝒖𝒑(𝒕)
𝒂(𝒕)
𝑽(𝒕)
Downshifting Table
𝜸𝒅𝒏(𝒕) 𝜸𝒄𝒎𝒅(𝒕)
TIMER_UP_SHIFT
HOLD_GEAR
UPSHIFT
𝜸𝒖𝒑 𝒕 > 𝜸 𝒕
𝒂 𝒕 ≤ 𝒂𝒏𝒕
𝒂 𝒕 ≤ 𝒂𝒏𝒕 𝑶𝑹 𝒂𝒇𝒕𝒆𝒓(𝝉)
𝜸𝒖𝒑 𝒕 ≤ 𝜸 𝒕
𝜸 𝒕 = 𝜸𝒄𝒎𝒅 𝒕
𝒂 𝒕 > 𝒂𝒏𝒕
TIMER_DN_SHIFT
𝜸𝒅𝒏 𝒕 < 𝜸 𝒕
𝜸 𝒕 = 𝜸𝒄𝒎𝒅 𝒕
𝒂 𝒕 ≤ 𝒂𝒏𝒕
𝒂 𝒕 ≤ 𝒂𝒏𝒕 𝑶𝑹 𝒂𝒇𝒕𝒆𝒓(𝝉)
𝜸𝒅𝒏 𝒕 ≥ 𝜸 𝒕𝜸(𝒕)
𝒂(𝒕)
State-machine
𝜸𝒄𝒎𝒅 𝒕 ← 𝜸 𝒕 + 𝟏
DOWNSHIFT𝜸𝒄𝒎𝒅 𝒕 ← 𝜸 𝒕 − 𝟏
𝒂 𝒕 > 𝒂𝒏𝒕
𝑎 𝑡 : Accelerator pedal position
𝑉 𝑡 : Vehicle speed
𝛾 𝑡 : Gear
𝛾𝑢𝑝 𝑡 : Upshifting Gear
𝛾𝑑𝑛 𝑡 : Downshifting Gear
𝛾𝑐𝑚𝑑 𝑡 : Gear Command
𝑎𝑛𝑡: accelerator pedal position above
which timer is by-passed
𝜏: minimum time shift criteria
must be met before shift occurs
Simulink Implementation
12
Look-up tables State-Machine
Look-up Tables
13
State-Machine
14
Shifting Strategy in Autonomie
15
Shifting Controller for Automatic Transmissions
16
VEH
VPA
GB
CTRL
DEMAND
Parameterization
17
𝑎𝑝𝑒𝑟𝑓
𝑎𝑒𝑐𝑜𝑑𝑛
𝛼𝑝𝑓,𝑒𝑐
𝑎𝑒𝑐𝑜𝑢𝑝
𝑎𝑛𝑡
𝜔𝑒𝑐𝑜𝑁→𝑁−1
𝜔𝑒𝑐𝑜2→1
𝜔𝑒𝑐𝑜𝑁−1→𝑁
𝜔𝑒𝑐𝑜1→2
𝜏𝜖𝑢𝑑𝑞𝑖𝑑𝑙𝑒
Shifting Controller for Manual Transmissions
18
VEH
DRV
DEMAND
DRV
GEAR
• Model and initialization are different from automatic, but very similar
• Same parameters as for automatic gearbox