Research On Estimation Of Vehicle Tyre Friction Based On FPGA

In recent years, the safety problem raised by vehicle has attracted more andmore people’s attention. At the same time, kinds of active safety systems areinvented. But all these safety systems have the same problem which is how toobtain the information of vehicle state and the tyre friction. As Some of theinformation can’t be gained from vehicle sensors, they must be estimated through aappropriate algorithm. Many researchers in the world have done deep research onthis problem and came to some achievement. But all of the tyre friction estimationalgorithms have high complexity, which results in long running time in MCU orDSP. To shorten the operation time, the issue about how to implement the tyrefriction estimation algorithm is discussed in this paper.In chapter two, some research on the algorithm of tyre friction estimation hasbeen done. Firstly, With the use of the basic theory of dynamic, the Dugoff tyremodel and the vehicle model are established In the specified coordinate.Secondly,To estimate the longitdinal tyre friction and the vehicle state, a sliding modeobserver and a nolinear observer are built seperately under the Dugoff model andthe vehicle model. In2.4section, the algorithm of tyre friction is discretized. Tomaximize the advantage of FPGA, the parallelism of the algorithm is analysed in2.5section. At last, In veDYNA software, we design three working conditionsunder which the discretized algorithm is simulated.At present, there are mainly two kinds of methods, Hardware descriptionlanguage and SOPC, to implement the tyre friction estimation algorithm based onFPGA. How to implement the tyre friction estimation in these two methods areseperately discussed in chapter three and chapter four.In chapter three, The tyre friction estimation is implelmented in Verilog HDL.Based on the analysis result of2.5section, the overall design of the system isillustrated and all of the basic function modules are extracted and programmed inModelSim.Chapter four mainly talks about how to implement the tyre friction estimationusing SOPC. The main flow of SOPC is illustrated and divided into two parts:hardware design and software design. The hardware design part is conducted inSOPC Builder, a toolbox of Quartus II software. According to customers’ needs,The appropriate CPU and peripherals are selected to build a hardware system. Atthe same time, based on C language, the software design part can also be completedin Nios II IDE.To compare these two kinds of methods, a testing platform is built based on DE4-230FPGA prototyping board. Under three typical working conditions, Thetwo implementations are compared with each other in running time and runningresults.