08-17-2017, 12:25 AM
[attachment=6455]
[u]Steer by Wire Technology and the Race to Save Energy
Product Names Harmonica Digital Servo Drives Controller
Some of the advantages of steer by wire technology are clearly apparent, as demonstrated in the Shell Eco-marathon, an energy saving competition. The goal of the Shell Eco-marathon competition is build a vehicle with the highest possible fuel efficiency a car that can cover the greatest possible distance on a single liter of fuel. To do well, the vehicle design must be optimized and streamlined to reduce all conceivable sources of energy loss. With this goal in mind, an electronic steering system enables optimal use of space in the vehicle.
Advantages of Electronic Steering Systems Electronic steering systems (steer by wire, SbW) are valued in the field of car manufacturing due to their flexibility and the mechanical decoupling of the chassis. Removing the standard steering column from the design and manufacturing equation simplifies interior design, reduces costs and reduces the requirements and processes of accident prevention and safety testing.
Technical Description
For the competition, Fortis Saxonia e. V. Chemnitz developed a new fuel cell vehicle, the Sax 2, which started in the prototype category.
Elmo Motion Control GmbH sponsored the Sax 2 eco car project at the Chemnitz University of Technology (CUT) and provided the team with Elmo's Harmonica compact servo drivers. Two Harmonica mini servo drivers control the rear-wheel steering system of the Sax 2.
The standard steering column was replaced by a driver-controlled analog joystick which sends signals to the Harmonica servo drivers used to control the back wheel of the Sax 2.
One of the main advantages of SbW technology is the small amount of space that is required for moving the joystick. Maximum flexibility is achieved by placing the joystick in the cockpit, which also allows for a very narrow chassis design: In turn, the narrow chassis minimizes the front surface and air resistance.
The angle and speed of turning the steering wheel is dependent on the actual speed of the vehicle, but because the center of gravity of the Sax 2 is very high, the danger of rollover due to a steering fault or error has been minimized via SbW. Additional software was used to reduce the risk of the vehicle overturning.
The overall system is powered by a hydrogen fuel cell system.
The implementation of a Stability Control Sensor is planned for the future.
The Challenges The highest possible level of function and flexibility is obtained with SbW technology. The implementation of additional software functions is possible and the software can be upgraded relatively quickly.