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The progress of the project until now has been seriously influenced by various technical problems that were probably quite dated. I am keeping a list of all the problems I encountered while becoming familiar with the laboratory equipment. I plan to expand the bullet points of this list later to make them more exhaustive. I will then add and integrate them to the main lab document. Hopefully this will make the settling-in period of new researchers in this lab shorter.
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Note about CPS usage. Since CPS now compute and send the 2D speed to cars, AndreaCPS is not compatible to previous ca2 versions. Viceversa my ca2 is not compatible with previous version of CPS. This is because the communication protocol between CPS and ca2 is now a little bit different. In general I would suggest using AndreaCPS instead of KevinCPS or LeoCPS. This because of the bug that involved the initial target detection. I did not check CPS versions that are previous to KevinCPS but it is likely that those versions do not have this bug since computer 1 and 2 do not send their information to computer 0 before sending them to cars.
CURRENT LAB PROBLEMS
- Motor of car 2 does not respond to PWM input.
- Cars steers are slightly biased. This is very evident in car 1. When the steer input signal is 0 they turn left.
- Cameras should be screwd to the metal support. Now everytime they move, the calibration must be done again. An extrinsic calibration (at least) should probably be performed again after this job.
- Sometimes the two chargers close to the whiteboard display the green light when cars are connected (i.e. they're done charging) but when I move the wires the light turns red.
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NEXT STEPS
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Steer control
- Model identification of steer_input -> curvature_radius.
- Steer controller designing and testing.
Predictor design
- Model identification of motor_input -> speed.
- Model identification of path-dependent disturbances (steer, slope and projection) on speed.
- Quantification of non-predictable path-dependent disturbances.
- Predictor implementation and testing.
Experiment
- Debugging of the collision avoidance algorithm with the new predictor on the simulator.
- Setting-up and testing of the experiment with only autonomous vehicles.
- Setting-up and testing of the final experiment with also human-driven vehicles.
DISTURBANCES ANALYSIS
In this section a quantitative analysis of the disturbances in the system is attempted. In order to deal in an easier way with the assumption of monotonicity and with the coupling between the steer and the motor input, the model is linearized and the lateral and the longitudinal components are separated. The coupling effect is seen as a disturbance. In the following the coordinate system will be relative to the path as represented in Figure coord_sys.jpg. In other words, y represents the position along the path while x the lateral distance from the path.
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