Package lejos.hardware.device.tetrix

Class TetrixServo

  • All Implemented Interfaces:
    Servo
    public class TetrixServo
extends java.lang.Object
implements Servo
    Basic servo motor abstraction. Servos are driven by a PWM signal from the controller with varying pulse widths controlling the rotational position of the servo actuator shaft.

    The HiTechnic Servo Controller allows setting of the PWM output from 0.75 - 2.25ms. Note that some servos may hit their internal mechanical limits at each end of this range causing them to consume excessive current and potentially be damaged.

    Author:
    Kirk P. Thompson

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      float getAngle()
      Returns the current servo angle as reverse calculated by the last call to setAngle().
      int getpulseWidth()
      Get the current PWM pulse width for the servo.
      void setAngle​(float angle)
      Sets the angle target of the servo.
      void setpulseWidth​(int microSeconds)
      Set the PWM pulse width for the servo.
      void setRange​(int microsecLOW, int microsecHIGH, int travelRange)
      Set the allowable pulse width operating range of this servo in microseconds and the total travel range.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Method Detail

      • setRange

        public void setRange​(int microsecLOW,
                     int microsecHIGH,
                     int travelRange)
              throws java.lang.IllegalArgumentException
        Set the allowable pulse width operating range of this servo in microseconds and the total travel range. Default for pulse width at instantiation is 750 & 2250 microseconds. Default for travel is 200 degrees.

        The midpoint of the pulse width operating range should normally be 1500 microseconds so the range extents should reflect this.

        This information must reflect the appropriate specifications and/or empirical characterization data of the specific servo used for the setAngle() method to be able to position the servo accurately.

        Specified by:
        setRange in interface Servo
        Parameters:
        microsecLOW - The low end of the servos response/operating range in microseconds
        microsecHIGH - The high end of the servos response/operating range in microseconds
        travelRange - The total mechanical travel range of the servo in degrees
        Throws:
        java.lang.IllegalArgumentException - if the range isn't within 750 and 2250
        See Also:
        setAngle(float)

      • setAngle

        public void setAngle​(float angle)
        Sets the angle target of the servo. The positional accuracy of this method requires that setRange() be called with the correct parameters to establish proper ranging conversion to internal controller representation of servo position.
        Specified by:
        setAngle in interface Servo
        Parameters:
        angle - Set servo angle in degrees.
        See Also:
        setRange(int, int, int), getAngle()

      • getAngle

        public float getAngle()
        Returns the current servo angle as reverse calculated by the last call to setAngle(). This is calculated from the internal byte representation used (calculated by setAngle()) to control the servo so the resolution will be affected by ranging factors set with setRange()

        The actual physical servo position may or may not be at the reported angle if mechanical limits have been reached.

        Specified by:
        getAngle in interface Servo
        Returns:
        Current servo angle
        See Also:
        setRange(int, int, int), setAngle(float)

      • setpulseWidth

        public void setpulseWidth​(int microSeconds)
                   throws java.lang.IllegalArgumentException
        Set the PWM pulse width for the servo. This must be in the range defined for the servo. This method allows manipulation of the servo position based on absolute pulse widths in microseconds.

        A servo pulse of 1500 microseconds (1.5 ms) width will typically set the servo to its "neutral" position. This is the "standard pulse servo mode" used by all hobby analog servos.

        The HiTechic Servo Controller allows setting of the PWM output from 750 to 2250 microseconds with a step resolution of 5.88 microseconds (1 byte is used to control the pulse width output) and this method will calculate and use the stepped value closest to value passed in microSeconds.

        Note that some servos may hit their internal mechanical limits at each end of this range causing them to consume excessive current and potentially be damaged.

        Specified by:
        setpulseWidth in interface Servo
        Parameters:
        microSeconds - The pulse width time in microseconds
        Throws:
        java.lang.IllegalArgumentException - if the range isn't within 750 and 2250
        See Also:
        setRange(int, int, int)

      • getpulseWidth

        public int getpulseWidth()
        Description copied from interface: Servo
        Get the current PWM pulse width for the servo.
        Specified by:
        getpulseWidth in interface Servo
        Returns:
        The pulse width time in microseconds