/// <summary>
    /// Collect observations. Number of calls to AddVectorObs should match with the
    /// observation vector size set in the Behavior Parameters inspector (of the Real body object).
    /// </summary>
    public override void CollectObservations()
    {
        // Shoulder extension/flexion
        AddVectorObs(leftShoulder.GetRelativeZ());

        // Elbow extension/flexion
        AddVectorObs(leftElbow.GetRelativeX());

        // Hand touch state (visual)
        AddVectorObs(ballScript.GetLastTouch());

        // Hand touch state (tactile)
        AddVectorObs(vibScript.GetLastVib());

        // Current Time
        AddVectorObs(Time.time);

        // Absolute hand distance error for logging
        AddVectorObs(Vector3.Distance(middleHand.transform.position, rubberArmController.getMiddleHand().transform.position));

        // Horizontal distance
        AddVectorObs(middleHand.transform.position.z - rubberArmController.getMiddleHand().transform.position.z);

        // Shoulder extension/flexion
        AddVectorObs(rubberArmController.getRelativeLeftShoulderZ());

        // Elbow extension/flexion
        AddVectorObs(rubberArmController.getRelativeLeftElbowX());
    }
 /// <summary>
 /// Get the elbow's x rotation relative to the initial position.
 /// </summary>
 /// <returns>float: The relative x rotation</returns>
 public float getRelativeLeftElbowX()
 {
     return(leftElbow.GetRelativeX());
 }