Class: DrivingPhysics::Car::Condition

Inherits:
Object
  • Object
show all
Defined in:
lib/driving_physics/car.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dir: DrivingPhysics.random_unit_vector, brake_temp: AIR_TEMP, brake_pad_depth:) ⇒ Condition 



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# File 'lib/driving_physics/car.rb', line 175

def initialize(dir: DrivingPhysics.random_unit_vector,
               brake_temp: AIR_TEMP,
               brake_pad_depth: )
  @dir = dir  # maybe rename to @heading ?
  @pos = Vector[0, 0]
  @vel = Vector[0, 0]
  @acc = Vector[0, 0]
  @fuel = 0.0   # L
  @lat_g = 0.0  # g
  @lon_g = 0.0  # g
  @wheelspeed = 0.0 # m/s (sliding when it differs from @speed)
  @brake_temp = brake_temp
  @brake_pad_depth = brake_pad_depth   # mm
end

Instance Attribute Details

#acc ⇒ Object (readonly)

Returns the value of attribute acc.



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# File 'lib/driving_physics/car.rb', line 172

def acc
  @acc
end

#brake_pad_depth ⇒ Object (readonly)

Returns the value of attribute brake_pad_depth.



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# File 'lib/driving_physics/car.rb', line 172

def brake_pad_depth
  @brake_pad_depth
end

#brake_temp ⇒ Object (readonly)

Returns the value of attribute brake_temp.



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# File 'lib/driving_physics/car.rb', line 172

def brake_temp
  @brake_temp
end

#dir ⇒ Object (readonly)

Returns the value of attribute dir.



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# File 'lib/driving_physics/car.rb', line 172

def dir
  @dir
end

#fuel ⇒ Object (readonly)

Returns the value of attribute fuel.



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# File 'lib/driving_physics/car.rb', line 172

def fuel
  @fuel
end

#lat_g ⇒ Object (readonly)

Returns the value of attribute lat_g.



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# File 'lib/driving_physics/car.rb', line 172

def lat_g
  @lat_g
end

#lon_g ⇒ Object (readonly)

Returns the value of attribute lon_g.



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# File 'lib/driving_physics/car.rb', line 172

def lon_g
  @lon_g
end

#pos ⇒ Object (readonly)

Returns the value of attribute pos.



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# File 'lib/driving_physics/car.rb', line 172

def pos
  @pos
end

#vel ⇒ Object (readonly)

Returns the value of attribute vel.



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# File 'lib/driving_physics/car.rb', line 172

def vel
  @vel
end

#wheelspeed ⇒ Object (readonly)

Returns the value of attribute wheelspeed.



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# File 'lib/driving_physics/car.rb', line 172

def wheelspeed
  @wheelspeed
end

Instance Method Details

#add_fuel(liters) ⇒ Object 



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# File 'lib/driving_physics/car.rb', line 273

def add_fuel(liters)
  @fuel += liters
end

#compass ⇒ Object 



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# File 'lib/driving_physics/car.rb', line 289

def compass
  DrivingPhysics.compass_dir(@dir)
end

#consume_fuel(liters) ⇒ Object 



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# File 'lib/driving_physics/car.rb', line 277

def consume_fuel(liters)
  @fuel -= liters
end

#lat_dir ⇒ Object

left is negative, right is positive



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# File 'lib/driving_physics/car.rb', line 209

def lat_dir
  DrivingPhysics.rot_90(@dir, clockwise: true)
end

#movement_dir ⇒ Object

note, we might be moving backwards, so not always @dir and we can’t normalize a zero vector if we’re not moving



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# File 'lib/driving_physics/car.rb', line 215

def movement_dir
  (speed == 0.0) ? @dir : @vel.normalize
end

#slide_speed ⇒ Object 



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# File 'lib/driving_physics/car.rb', line 285

def slide_speed
  (speed - @wheelspeed).abs
end

#speed ⇒ Object 



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# File 'lib/driving_physics/car.rb', line 281

def speed
  @vel.magnitude
end

#tick!(force:, mass:, tire:, env:) ⇒ Object 



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# File 'lib/driving_physics/car.rb', line 219

def tick!(force:, mass:, tire:, env:)
  # take the longitudinal component of the force, relative to vel dir
  vel_dir = @vel.zero? ? @dir : @vel.normalize
  lon_force = force.dot(vel_dir)
  @wheelspeed = nil

  if lon_force < 0.0
    is_stopping = true
    if @vel.zero?
      @acc = Vector[0,0]
      @wheelspeed = 0.0
      @lon_g = 0.0

      # TODO: update any other physical vars
      return
    end
  else
    is_stopping = false
  end

  # now detect sliding
  nominal_acc = DrivingPhysics.acc(force, mass)
  init_v = @vel

  if nominal_acc.magnitude > tire.max_g * env.g
    nominal_v = DrivingPhysics.vel(@vel, nominal_acc, dt: env.tick)

    # check for reversal of velocity; could be wheelspin while
    # moving backwards, so can't just look at is_stopping
    if nominal_v.dot(@vel) < 0 and is_stopping
      @wheelspeed = 0.0
    else
      @wheelspeed = nominal_v.magnitude
    end
    @acc = nominal_acc.normalize * tire.max_g * env.g
  else
    @acc = nominal_acc
  end

  @vel = DrivingPhysics.vel(@vel, @acc, dt: env.tick)
  @wheelspeed ||= @vel.magnitude

  # finally, detect velocity reversal when stopping
  if is_stopping and @vel.dot(init_v) < 0
    puts "crossed zero; stopping!"
    @vel = Vector[0, 0]
    @wheelspeed = 0.0
    @lon_g = 0.0
  end

  @lon_g = @acc.dot(@dir) / env.g
  @pos = DrivingPhysics.pos(@pos, @vel, dt: env.tick)
end

#to_s ⇒ Object 



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# File 'lib/driving_physics/car.rb', line 190

def to_s
  [[compass,
    format('P(%d, %d)', @pos[0], @pos[1]),
    format('V(%.1f, %.1f)', @vel[0], @vel[1]),
    format('A(%.2f, %.2f)', @acc[0], @acc[1]),
   ].join(' | '),
   [format('%.1f m/s', speed),
    format('LatG: %.2f', lat_g),
    format('LonG: %.2f', lon_g),
    format('Whl: %.1f m/s', @wheelspeed),
    format('Slide: %.1f m/s', slide_speed),
   ].join(' | '),
   [format('Brakes: %.1f C %.1f mm', @brake_temp, @brake_pad_depth),
    format('Fuel: %.2f L', @fuel),
   ].join(' | ')
  ].join("\n")
end