Electronic differential: Difference between revisions

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The main purpose of the electronic differential is to replace the mechanical differential in multi-drive systems, providing the required torque for each driving wheel and allowing different wheel speeds. When cornering, the inner and outer wheels rotate at different speeds, because the inner wheels describe a smaller turning radius. The electronic differential uses the steering wheel command signal and the motor speed signals to control the power to each wheel so that all wheels have the maximum torque they need.

Functional description

The classical automobile drive train is composed by a single motor providing torque to one or more driving wheels. The most common solution is to use a mechanical device to distribute torque to the wheels. This device, called mechanical differential, allows different wheel speeds when cornering. With the emergence of electric vehicles new drive train configurations are possible. Multi-drive systems become easy to implement due to the large power density of electric motors. These systems, usually with one motor per driving wheel, need an additional top level controller which performs the same task as a mechanical differential.

The ED scheme has several advantages over a mechanical differential^[1]:

simplicity - it avoids additional mechanical parts such as a gearbox or clutch;
independent torque for each wheel allows additional capabilities (e.g., traction control, stability control);
reconfigurable - it is reprogrammable in order to include new features or tuned according to the driver’s preferences;
allows distributed regenerative braking;
the torque is not limited by the wheel with least traction, as it is with a mechanical differential.
faster response times;
accurate knowledge of traction torque per wheel.

Applications

Several applications of this technology have proven successful and have increased vehicle performance. The application range is wide and includes the huge T 282B ^[2] from Liebherr which is considered the world largest truck. This earth-hauling truck is driven by an electric propulsion system composed by two independent electric motors. These motors providing a maximum power of 2700kW are controlled in order to adjust their speeds when cornering, thus increasing traction and reducing tire wear. The Eliica is also equipped with electronic differential; this eight-wheeled electric vehicle is capable of driving up to 370km/h whilst maintaining perfect torque control on each wheel. Smaller vehicles for traction purposes and System on Chip controllers for generic vehicular applications are also available.

References

[1] "Future vehicle driven by electricity and Control-research".

[2] "Liebherr T282B official webpage".

[1]

[2]

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-The main purpose of the '''electronic differential''' is to substitute the [[Differential (mechanical device)|mechanical differential]] in multi-drive systems providing the demanded [[torque]] for each driving wheel and allowing different wheel speeds.
+The main purpose of the '''electronic differential''' is to replace the [[Differential (mechanical device)|mechanical differential]] in multi-drive systems, providing the required [[torque]] for each driving wheel and allowing different wheel speeds.  When cornering, the inner and outer wheels rotate at different speeds, because the inner wheels describe a smaller turning radius.  The electronic differential uses the [[steering wheel]] command signal and the [[motor]] speed signals to control the power to each wheel so that all wheels have the maximum torque they need.
-When cornering, the inner and outer wheels rotate at different speeds. This happens because the former describes a smaller turning radius. The electronic differential uses the [[steering wheel]] command signal to control each wheel speed in order to smoothly perform the turning.
 ==Functional description==
-The classical [[automobile]] [[drive train]] is composed by a single [[Internal combustion engine|motor]] providing torque to one or more driving wheels. The most common solution is to use a mechanical device to distribute torque to the wheels. This device, called [[Differential (mechanical device)|mechanical differential]], is responsible to allow different wheel speed when cornering. With the emergence of [[electric vehicle]]s new drive train configurations are possible. Multi-drive systems become easy to implement due to the large power density of [[electric motor]]s. These driving schemes with one motor per driving wheel need an additional top level controller which is responsible to perform the same task as the mechanical differential. Named electronic differential, it is capable of substituting its mechanical counterpart with significant advantages.
+The classical [[automobile]] [[drive train]] is composed by a single [[Internal combustion engine|motor]] providing torque to one or more driving wheels. The most common solution is to use a mechanical device to distribute torque to the wheels. This device, called [[Differential (mechanical device)|mechanical differential]], allows different wheel speeds when cornering.  With the emergence of [[electric vehicle]]s new drive train configurations are possible. Multi-drive systems become easy to implement due to the large power density of [[electric motor]]s. These systems, usually with one motor per driving wheel, need an additional top level controller which performs the same task as a mechanical differential.
+The ED scheme has several advantages over a mechanical differential<ref>{{cite web | url= http://ieeexplore.ieee.org/search/srchabstract.jsp?arnumber=1339466&isnumber=29535&punumber=41&k2dockey=1339466@ieeejrns&query=%28+uot%3Cin%3Emetadata+%29&pos=1
-The ED scheme substitutes the mechanical differential with several advantages:
-*simplicity, it avoids additional mechanical parts like [[gearbox]]es or [[clutch]];
-*independent torque for each wheel allows additional capabilities (e.g., [[traction control system|traction control]], [[stability control]]);
-*reconfigurable, it is reprogrammable in order to include new features or tuned according to the driver’s preferences;
-*allows distributed [[regenerative braking]];
-*no mechanical differential limitation where the torque is limited by the wheel with least traction.
-Moreover, a multi-drive traction system with distributed electric motors have advantages over the traditional solutions<ref>{{cite web | url= http://ieeexplore.ieee.org/search/srchabstract.jsp?arnumber=1339466&isnumber=29535&punumber=41&k2dockey=1339466@ieeejrns&query=%28+uot%3Cin%3Emetadata+%29&pos=1
  | title= Future vehicle driven by electricity and Control-research }}</ref>:
+* simplicity - it avoids additional mechanical parts such as a [[gearbox]] or [[clutch]];
-# faster response times;
+* independent torque for each wheel allows additional capabilities (e.g., [[traction control system|traction control]], [[stability control]]);
-# accurate knowledge of traction torque per wheel.
+* reconfigurable - it is reprogrammable in order to include new features or tuned according to the driver’s preferences;
+* allows distributed [[regenerative braking]];
+* the torque is not limited by the wheel with least traction, as it is with a mechanical differential.
+* faster response times;
+* accurate knowledge of traction torque per wheel.
 ==Applications==
@@ Line 23: / Line 20: @@
 [[Image:Eliica.jpg|thumb|175px|Eliica shown at [[Intex Osaka]] ]]
-Several applications of this technology proved to be successful and have increased the vehicle performance. The application range is wide and includes the huge [[Liebherr T 282B|T 282B]] <ref>{{cite web | url= http://www.liebherr.com/me/en/40787.asp| title= Liebherr T282B official webpage}}</ref> from [[Liebherr]] which is considered the world largest truck. This earth-hauling [[truck]] is driven by an electric propulsion system composed by two independent electric motors. These motors providing a maximum power of 2700kW are controlled in order to adjust their speeds when cornering thus increasing traction and reducing tire wear.
+Several applications of this technology have proven successful and have increased vehicle performance. The application range is wide and includes the huge [[Liebherr T 282B|T 282B]] <ref>{{cite web | url= http://www.liebherr.com/me/en/40787.asp| title= Liebherr T282B official webpage}}</ref> from [[Liebherr]] which is considered the world largest truck. This earth-hauling [[truck]] is driven by an electric propulsion system composed by two independent electric motors. These motors providing a maximum power of 2700kW are controlled in order to adjust their speeds when cornering, thus increasing traction and reducing tire wear.
-The [[Eliica]] is also equipped with electronic differential; this eight-wheeled electric vehicle is capable of driving up to 370km/h whilst maintaining perfect torque control on each wheel. Smaller vehicles for traction purposes and [[System on Chip]] controllers for generic vehicular applications are also available from WeMoveU company.<ref>{{cite web | url=http://www.wemoveuev.com/_mgxroot/page_10737.html | title= WeMoveU provides System On Chip Electronic Differential controller.}}</ref><ref>{{cite web | url= http://www.electrictractor.com/html/tow_prod.shtml | title= Electric Tractor’s Electric Ox }}</ref>
+The [[Eliica]] is also equipped with electronic differential; this eight-wheeled electric vehicle is capable of driving up to 370km/h whilst maintaining perfect torque control on each wheel. Smaller vehicles for traction purposes and [[System on Chip]] controllers for generic vehicular applications are also available.
 ==References==