Introduction to Baidu intelligent transportation model of Shanghai Maritime University

Zhuo Qing 2021-08-11 17:56:21 阅读数:499

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introduction baidu intelligent transportation model

Jane Medium : In order to better complete the competition task of the 16th Baidu intelligent transportation creative group , And when the rules require self-made car models , We design the base plate by ourselves , Task frame , Main control and motor drive module of lower computer , To complete the required tasks .

key word The smart car race , Shanghai Maritime University , Creative group

One 、 Mechanical structure of vehicle model

▲ chart 1 Front view of car model

▲ chart 1 Front view of car model

▲ chart 2 Side view of car model

▲ chart 2 Side view of car model

▲ chart 3 Model chassis 3D Model

▲ chart 3 Model chassis 3D Model

In order to reduce weight and facilitate fixing structural parts , The bottom plate of the car model is spliced and fixed with aluminum plate and acrylic plate . The wheel consists of a front driving wheel and a pair of driven omnidirectional wheels , In design , The driven universal wheel is placed inside the vehicle body , Reduce wheelbase , This can effectively reduce the turning radius . At the same time, because the omni-directional wheel can move and rotate in all directions , Compared with ordinary rubber wheel , Less resistance , More flexible .

▲ chart 4 Driven omnidirectional wheel

▲ chart 4 Driven omnidirectional wheel

The upper task structure constitutes the main task completion module and identification module of the vehicle . The main camera is fixed to the chassis through a carbon fiber rod . The side camera is fixed in the middle of the model through aluminum alloy plate and steering gear . The steering gear controls the camera to look to the left and right .

▲ chart 5 Camera fixing structure

▲ chart 5 Camera fixing structure

Mark pen shooting is required in the competition , On the basis of easy control , The selected high torque motor is combined with the rack , Gear rack mechanism . Thus, the rotation of the gear is changed into the translation of the rack , Realize the extension and retraction of the marker . meanwhile , In order to avoid external interference during the competition or improper direction of pen head during model transportation , The marker holder designed by us can not only connect the rack, but also manually adjust the angle . It is convenient to adjust the position of the marker in the debugging stage , Improve accuracy .

▲ chart 6 Rack and pinion transmission mechanism

▲ chart 6 Rack and pinion transmission mechanism

▲ chart 7 Marker fixing structure

▲ chart 7 Marker fixing structure

It also requires a foam ball to carry the model , And place the ball in the designated place . We use steering gear to control this task 3D The printout completes the task of placing the ball , Through irregular shape design , Under the condition of ensuring that the small ball does not fall, the small ball can be poured into the designated place more conveniently without being dragged out of the box . At the same time, because the arc design we use is not symmetrical , Instead, it uses a large arc near the model , Small radian in the distance . Dumping " Grain and grass " The ball is more silky , Control does not require a larger angle , Reduced control pressure .

▲ chart 8 Ball prevention device

▲ chart 8 Ball prevention device

▲ chart 9 Structural parts 3D Simulation diagram

▲ chart 9 Structural parts 3D Simulation diagram

▲ chart 10 Mechanical arm

▲ chart 10 Mechanical arm

In the competition, the model needs to grab the box and bring it back to the starting place of the model . Here we choose to realize the task of grabbing box loot through manipulator . In order to catch the box, it is not easy to fall , When selecting the mechanical claw , Use mechanical claws with serrations , Because the cube is made of foam. , This type of mechanical claw is tighter when grasping , In addition, we choose high torque steering gear , This will not fall after grabbing the box .

▲ chart 11 Flag raising device

▲ chart 11 Flag raising device

Flag raising task in competition , Through one 360 The steering gear is connected with three flags to realize the flag raising control of different flags . Connect the steering gear and flag with self-made Tee Pieces . Simple control at the same time , It can also reduce the overall mass of the body .

▲ chart 12 Flag raising tee connector

▲ chart 12 Flag raising tee connector

Two 、 Circuit design

The control of vehicle model is mainly used edge board And self-made lower computer motherboard , The upper computer adopts the software of Baidu company edge board, The lower computer is manufactured by NXP K60 Processor . The communication between upper computer and lower computer is realized through wired serial port .

When designing the master control of the lower computer , The original version was to share a power supply for multiple steering gears , Then in practical application , It is found that due to the large torque of the selected steering gear , A single power supply cannot realize the simultaneous use of multiple steering gears . therefore , For greater torque , And multiple steering gears work at the same time , In terms of steering gear power supply, two steering gears share the same power supply . meanwhile , A diode is added at the connection between the steering gear and the main board to prevent the current recoil of the steering gear , The service life of the circuit board is improved .

▲ chart 13 Lower machine 3D Simulation diagram

▲ chart 13 Lower machine 3D Simulation diagram

▲ chart 14 Physical drawing of lower computer

▲ chart 14 Physical drawing of lower computer

The Organizing Committee of this competition requires the use of specific reduction motors . Since the motor is a specific interface designed for the sponsor board , For the convenience of circuit design , Remove the motor encoder , At the same time, the self drawn driving circuit is used to output PWM wave . The drive circuit uses a erasure drive chip , One board can be used by two motors .

▲ chart 15 Simulation diagram of driving circuit board

▲ chart 15 Simulation diagram of driving circuit board

3、 ... and 、 Programming

This Baidu group needs to use Baidu's power card for in-depth learning , therefore , In identification and identification of markers . We will use the model provided by Baidu for in-depth training , For model training , We combine the traditional racing group , By laying electromagnetic wires , Installation inductance . The deviation is obtained by electromagnetic tracing and compared with edge board Each frame of the collected image is trained , In this way, the turning is more smooth when the vehicle model is officially tracing , There's no pause .

The communication mode between the upper computer and the lower computer , We use serial port , Easy to use . The upper computer sends instructions , The lower computer executes the corresponding task after receiving it .

Four 、 Competition view

I'm very glad to have the opportunity to participate in Baidu intelligent transportation group this year , And in " Encourage exploration , The pursuit of excellence " Encouraged by the idea of smart car . We built the model independently , Circuit design , And programming . At the same time, I learned a lot of knowledge in this process , I have mastered many abilities that I haven't learned before , The intelligent vehicle is realized " Based on training , The key is to participate in " The purpose of . Although in the end, our total online and offline results only ranked ninth in the regional competition , But we build models by ourselves , Learn to draw boards by yourself , Study in depth . A lot of gains , I'm also very happy to meet friends with the same interests during the competition , Communicate with each other , Learn from others' strong points and close the gap .


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