PID experiment - old stuff

#!/usr/bin/env ruby

# PID Simulation
# Andrew Horsman
# 01/19/2011

# Notes:
# Arm range of motion should be a 90 degree arc, 33% of the potentiometer's range of
# motion.

class PID

  def GetCurrentPosition
    return @current_arm_position
  end

  def GetSetpoint
    @direction_multiplier *= -1 if @setpoint > 66 || @setpoint < 33

    @setpoint += @direction_multiplier * 1
  end

  def CalculateMotorOutput
    if @result > 1
      return 1
    elsif @result < -1
      return -1
    else
      return @result
    end
  end
  
  def CalculateArmMovement
    return @motor_output * 3
  end

  def SetMotor
    temp = 0
    temp += @Kp * @current_error
    temp += @Ki * @total_error
    temp += @Kd * (@current_error - @previous_error)
  
    @result                = temp
    @motor_output          = CalculateMotorOutput()
    @current_arm_position += CalculateArmMovement()
  end

  def WriteFileBegin
    File.open(@filename, "w") do |file|
      file.puts "Time,Current Position,Setpoint,Multiplier,Previous Error,Error,Total Error,Result,Motor Output"
    end
  end

  def WriteFileLoop
    File.open(@filename, "a") do |file|
      file.print @current_time.to_s + ","
      file.print @current_arm_position.to_s + ","
      file.print @setpoint.to_s + ","
      file.print @direction_multiplier.to_s + ","
      file.print @previous_error.to_s + ","
      file.print @current_error.to_s + ","
      file.print @total_error.to_s + ","
      file.print @result.to_s + ","
      file.print @motor_output.to_s
      file.puts
    end
  end

  def initialize

    @Kp = ARGV[0].to_f
    @Ki = ARGV[1].to_f
    @Kd = ARGV[2].to_f

    puts "#{@Kp} #{@Ki} #{@Kd}"

    @period = 60
    @current_time = 0
    @current_arm_position = 33
    @direction_multiplier = 1
    @setpoint = 33
    @previous_error = 0
    @current_error  = 0
    @total_error    = 0
    @result = 0
    @motor_output = 0
    @filename = "simulation#{Time.now.to_i.to_s}_#{@Kp}_#{@Ki}_#{@Kd}.csv"

    WriteFileBegin()

    1.upto(400) do |loop|

      GetSetpoint()
      @current_error = @setpoint - GetCurrentPosition()
      @total_error  += @current_error

      WriteFileLoop()
      SetMotor()

      @previous_error = @current_error
      @current_time  += @period

    end
  end
end

test = PID.new