#!/usr/bin/env python import sys,tty,termios import datetime import time import dateutil.parser import filenames from select import select from car import Car import Adafruit_CharLCD as LCD folder = 'recordings' prefix = 'recording' suffix = '.csv' recording_file_path = filenames.next_filename(folder=folder,prefix=prefix,suffix=suffix) def write_command_to_car(s): command = open('/dev/car','w') command.write(s) def getch(): import sys, tty, termios fd = sys.stdin.fileno() old_settings = termios.tcgetattr(fd) try: tty.setraw(sys.stdin.fileno()) ch = sys.stdin.read(1) finally: termios.tcsetattr(fd, termios.TCSADRAIN, old_settings) return ch
def calibrate_braking(test_esc=1350,max_speed=1.,total_track_length=3.,stop_track_length=2.,note='na'): run_track_length = total_track_length - stop_track_length car = Car() time.sleep(0.5) car.zero_odometer() car.set_rc_mode(); goal_heading = car.heading_degrees() # accelerate in straight line until you get to desired speed print ('accelerating to speed of '+str(max_speed)) v = 0.0 # assume we start at zero speed aborted = False while v < max_speed: if car.odometer_meters() > run_track_length: aborted = True abort_reason = "ran out of track" break; esc = car.esc_for_velocity(v+2.5) steer = car.steering_for_goal_heading_degrees(goal_heading) car.set_esc_and_str(esc,steer) time.sleep(0.02) v = car.get_velocity_meters_per_second() print('done accelerating at {:4.1f} meters'.format(car.odometer_meters())) print('testing at esc: {}'.format(test_esc)) queue = Queue.Queue() car.add_listener(queue) data = [] # set the esc to given test setting while True: # go straight and record data until one of three things happens esc = test_esc steer = car.steering_for_goal_heading_degrees(goal_heading) car.set_esc_and_str(esc,steer) message = queue.get(block=True, timeout = 0.05) data.append(message) # # 1. You come to a full stop v = car.get_velocity_meters_per_second() if v <= 0.: print('test concluded at velocity zero') break # 2. Your speed stabilizes # 3. You reach distance limit if car.odometer_meters() > run_track_length: print('test length exceeded, allowing room to stop') break # 4. You detect that you are skidding car.remove_listener(queue) if v > 0: print('applying safety brake at {} meters and velocity {}'.format(car.odometer_meters(), v)) # put on "safe level" of brakes until your speed reaches zero (or negative) while v > 0: esc = 1350 steer = car.steering_for_goal_heading_degrees(goal_heading) car.set_esc_and_str(esc,steer) time.sleep(0.02) v = car.get_velocity_meters_per_second() # set everything to neutral final_distance = car.odometer_meters() print('final distance: {} meters'.format(final_distance)) car.set_manual_mode() # save the results of braking to two files # car dynamics in one file # test settings in another file # do a quick analysis of data and print results prefix = 'esc/{}_start_{}_esc_{}'.format(note,int(max_speed*10),int(test_esc)) f = open(next_filename(folder = 'data', prefix = prefix, suffix = '.csv'), 'w') print ('seconds,meters,us,esc,odometer_ticks,odometer_last_us,ax,spur_delta_us,spur_odo',file=f) for p in data: p.seconds = (p.us-data[0].us)/1000000. p.meters = (p.odometer_ticks-data[0].odometer_ticks)*car.meters_per_odometer_tick fields = [p.seconds,p.meters,p.us,p.esc,p.odometer_ticks,p.odometer_last_us,p.ax,p.spur_delta_us,p.spur_odo] print(",".join([str(field) for field in fields]), file=f) print('np polyfit 2 result',np.polyfit([p.seconds for p in data], [p.meters for p in data], 2)) print('np polyfit 3 result',np.polyfit([p.seconds for p in data], [p.meters for p in data], 3)) # distance to stop from speed, distance left in track # whether skidding occurred # estimate of acceleration using linear fit # estimate of acceleration using polynomial fit (TBD: model for this, probably adding k*v^2 term for wind resistance) car.reset_odometry() time.sleep(0.01) route = reverse_route(final_distance, max_a=0.5, max_v=2.) play_route(route, car = car) car.set_manual_mode()