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Aftermarket Lane Keep Assist and Adaptive Cruise Control

Discussion in 'Gen 3 Prius Accessories and Modifications' started by hayden55, Dec 19, 2017.

  1. hayden55

    hayden55 Member

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    Alright I've read through here before and seen that people have created their own ACC (DRCC) using a lidar camera and then having commands sent to a device that controlled each mode of the oem cruise control. I would also like to add brake input to that but I was wondering how the oem pre-collision system applied the brake? If I send a signal to the brake pedal can I get the car to stop or will it only stop to a certain degree of aggressiveness and then require mechanical input for the next level of effort? Also does anybody know the trailing distance in time or seconds of the stock ACC system?
    On to the LKA system. I know that the cars equipped with the oem pre collision system have a different steering control module. These two modules are different and cannot be interchanged. It was explained that the pre collision lka system was able to note the steering rack angle in degrees and able to add torque inputs into the oem rack to achieve a certain steering angle to push the car from side to side to center the car in the lane. Basically the car can steer itself to a light degree. What is the difference in how the non equipped car keeps track of its steering position angle? Does it have this ability? Also, what kind of output does the steering wheel give when turned from side to side? Is it like a potentiometer and increases or decreases resistance from side to side when turned? I've seen that the LKA equipped cars receive signals from the oem lka camera on the cars relative position in the lane and are able to input a signal to the steering rack and the wheel actually turns. Is this possible on the non lka equipped cars?
     
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  2. huclee

    huclee Junior Member

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    I added my DIY ACC to my Camry hybrid as you seem before. I know it is possible to do what you want to do, but maybe too costly comparing to buy a new car with these functions.

    Z Hobby 自製自動跟車ACC adaptive cruise control DRCC diy homemade - Networked Embedded Autonomous sysTem (NEAT) LAB @ccu.edu.tw 中正大學 通訊系

    Basically you are talking about 'actuator' (steering for LKA or push the brake). But you may use original cruise control (CC) stick of prius to try to managing a constant distance between your car & the front car; while the front car is distance is getting close, you simply 'slow down' your car speed with CC (lower the stick), it effect is similar to 'engine brake' and actually similar to what you call 'light brake'. I mean it is possible to implement a ACC without add 'brake' actuator. Sending command via CANBUS to the car to apply brake & LKA is also possible but seems not a good idea, because this may cause some unknown or unexpected problem and even damage the car (see my previous experience what the chinese ADAS kill my speedometer)

    TOYOTA DTC B2282 problem - Networked Embedded Autonomous sysTem (NEAT) LAB @ccu.edu.tw 中正大學 通訊系

    Of course if you want to made a 'pre-collision' function, as far as I know you need to do a lot, at least brake actuator/servo. Some chinese companies already sell this kind of product in TaoBao

    Google Translate



    Add a brake servo is necessary. But how can you ensure its reliability? if it is stuck it may cause dangerous situation. At least I do not believe this kind of product..

    For detecting the lane for LKA is simple, the chinese ADAS (camera based) can out the lane distance for LKA. But! The major problem is still reliability, I asked their engineers and they do not recommend to do so because even themselves do not trust this system.
     
  3. hayden55

    hayden55 Member

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    Have you looked into Comma AI? This is what I'm planning to use. Waiting for a chip to come from china so hopefully I can build my controller in the next 10 days. I'll build my controller. have the android phone running autopilot, send signals to an arduino to control the epas rack and the cc circuit. I just think the gas and brake pedal would be the next step to get the system to function under 25 mph.

    The big part with safety is setting up hard coded safety limits for gas, brake, and steering control. Steering up to 5 degrees etc... The electronic side of the brake can only apply the electric motor so its not able to panic stop etc...
     
  4. hayden55

    hayden55 Member

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  5. huclee

    huclee Junior Member

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    Oh My god this is really my dream project. But have no idea whether it can support my 2012 Camry Hybrid. I will look this project deeper and see if what I can do. At least I really wish to have an aftermarket ACC for my car. I do want to buy a new car but Toyota in Taiwan is really shameful, until today Toyota still sell the prius 2017/2018 WITHOUT low-speed ACC & AEB (only beep for warning driver to brake himself), since it is the best-selling car company in Taiwan, they do not want to sell the car with all safety equipment. They want to sale a new model car without safety equipment, and then next year add some and claim this is a new model and sell again.... damn it.
     
  6. hayden55

    hayden55 Member

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    Yeah your car isn't directly supported. So we will have to work on getting the system to communicate together like a supported oem system.
     
  7. huclee

    huclee Junior Member

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    I had checked comma.ai project. Very interesting and I might contact with the project leader and see if it is possible to use the knowledge from this project. I am not sure but seems comma.ai support to read radar signal from canbus for Honda CR-V so it can use for ACC/LKAS, as the Comma ai's camera is still can not see to far as my chinese ADAS. Fusion of radar/camera data is required for ACC & LKAS.

    It is very interesting as comma.ai support many features from reading canbus which I am not yet try to do. May be it can be one of the goal in the near future.

    Happy to receive any comments.
     
  8. hayden55

    hayden55 Member

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    Yeah its one of those things where you choose a level of functionality and then go for it. I know right off the bat you can get a comma unit to control an electric steering rack through an arduino and forgo canbus altogether. Next... people are running cc circuits and full regen (longpress down enables full regen for time of press) to maintain speed directly to the spiral cable through the arduino. So both have functioned separately it just needs to be combined.

    I think comma has the most test miles logged of anyone because of their open sourcing. 27.5M mi. That is extremely promising along with the low cost of entry with their hardware and free software. Comma ai just started supporting GPS 10cm, stoplights, stop signs, and lane change as well. SO COOL.
    I'm starting to think the best route will be to buy a new takeoff radar plate system from a honda or toyota since they are the cheapest and function well and then go for it. Should submit similar values for you to adapt into the tables.
     
  9. huclee

    huclee Junior Member

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    I finally integrated a distance radar for my Camry for ACC function. Please find the test video above.

    This version of homemade ACC is based on a FMCW radar. I built an embedded system to read signals from the radar and use it to control the cruise control plus/minus keys. Now the next goals is to fine-tune the adaptive cruise control algorithm to make it more smooth.

    some updates will be post here Z Hobby 自製自動跟車ACC adaptive cruise control DRCC diy homemade - Networked Embedded Autonomous sysTem (NEAT) LAB @ccu.edu.tw 中正大學 通訊系

    ==================
    This version of homemade ACC is a modification to my Toyota Camry Hybrid 2012. The info of the LCD --
    CLOSE -- too close need brake
    GOOD -- current distance is good, keep the speed
    FAR -- the front car is far, accelerate now
    T-FAR -- the front car is too far, the user need to take control
    The bar indicate the desire distance for three level SHORT/MIDDLE/LONG
    The "S" indicates my car's speed in kph
    L: first number is the front car distance in m, the second number is my car's speed in meter per second
    ACC ON/OFF indicates the current system is on or off.
    The FMCW radar can detect the front car at most more than 140 meter on the current installation. But for stable tracking the front car, less than 70 meters is much better.
     
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  10. huclee

    huclee Junior Member

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    I added some description for easy understanding the actions of this ACC system