Lesson8.md

@@ -279,11 +279,11 @@ The robot may have had trouble getting safely up the ramps using this approach,
 
 #### Combining line following ramp climbing with piloted platform turns
 
-Initially, we included code from **_GodBot.java_** [10] in a copy of **_SimplePilot.java _** [16], **_PilotedCarLineFollower.java _** [17], to drive the robot up the ramp instead of using pilot.forward(). In the API for DifferentialPilot [TODO ref. til [http://www.lejos.org/nxt/nxj/api/lejos/robotics/navigation/DifferentialPilot.html](http://www.lejos.org/nxt/nxj/api/lejos/robotics/navigation/DifferentialPilot.html)] it is stated that the results of other objects making calls to the motors when DifferentialPilot is in use are unpredictable. We had trouble figuring out how to separate line following control from the differential pilot’s control, to be able to switch between them. Our first attempt was to instantiate the DifferentialPilot within the if-statement that captures the case where the robot reads black on both sensors, so that it would only try to run in this isolated case and would be terminated upon exit from the if-statement’s scope. The robot had no trouble getting up the first ramp using line following and individual control of the motors, and it performed the turn on the first platforms - but after this, when exiting the if-statement, the robot started randomly turning and racing around. We spent several hours trying out different approaches to getting the differential pilot to work along with the GodBot line following, but did not succeed.
+Initially, we included code from **_GodBot.java_** [10] in a copy of **_SimplePilot.java_** [16], **_PilotedCarLineFollower.java_** [17], to drive the robot up the ramp instead of using pilot.forward(). In the API for DifferentialPilot [TODO ref. til [http://www.lejos.org/nxt/nxj/api/lejos/robotics/navigation/DifferentialPilot.html](http://www.lejos.org/nxt/nxj/api/lejos/robotics/navigation/DifferentialPilot.html)] it is stated that the results of other objects making calls to the motors when DifferentialPilot is in use are unpredictable. We had trouble figuring out how to separate line following control from the differential pilot’s control, to be able to switch between them. Our first attempt was to instantiate the DifferentialPilot within the if-statement that captures the case where the robot reads black on both sensors, so that it would only try to run in this isolated case and would be terminated upon exit from the if-statement’s scope. The robot had no trouble getting up the first ramp using line following and individual control of the motors, and it performed the turn on the first platforms - but after this, when exiting the if-statement, the robot started randomly turning and racing around. We spent several hours trying out different approaches to getting the differential pilot to work along with the GodBot line following, but did not succeed.
 
 ##### DifferentialPilot line following
 
-Deciding to take a break from attempting the combined approach, we resorted to implementing line following using the DifferentialPilot’s arc-method, in the class **_PilotedLineFollower.java _**[18] [TODO pretty?]. It proved difficult to properly steer the robot according to divergence in the black/white readings of the sensors. Though this was perhaps most likely due to a limited overview of how to utilize our error measurements in the arguments to **_arc()_** and/or increasing tiredness and frustration levels, we temporarily gave up on creating a satisfactory implementation. Instead, we began an implementation using a switcher to switch between behaviors implemented in an interface. This is described in the section below. After some debate regarding this solution (to be found in the section below), we continued the attempt at implementing line following using DifferentialPilot. We experimented with different parameters for **_arc()_** and introduced a turn utilizing **_rotateRight()_** to turn until aligned with the bottom bar of the Y on the platform in order to let the robot more easily find its way back on track after making a platform turn. We also performed other minor additions. We managed to get the robot to the second platform, successfully performing the intermediate turn operation on the first platform (see Video 7). At some point, however, the robot began failing in detecting the black end line - perhaps due to poor lighting in the later hours of the day, perhaps due to the sensors being raised as they were sometimes scraping on the track, and perhaps simply due to low battery. As black sensing was still working for the other two ongoing implementations, we decided to leave the DifferentialPilot at this.
+Deciding to take a break from attempting the combined approach, we resorted to implementing line following using the DifferentialPilot’s arc-method, in the class **_PilotedLineFollower.java_** [18]. It proved difficult to properly steer the robot according to divergence in the black/white readings of the sensors. Though this was perhaps most likely due to a limited overview of how to utilize our error measurements in the arguments to **_arc()_** and/or increasing tiredness and frustration levels, we temporarily gave up on creating a satisfactory implementation. Instead, we began an implementation using a switcher to switch between behaviors implemented in an interface. This is described in the section below. After some debate regarding this solution (to be found in the section below), we continued the attempt at implementing line following using DifferentialPilot. We experimented with different parameters for **_arc()_** and introduced a turn utilizing **_rotateRight()_** to turn until aligned with the bottom bar of the Y on the platform in order to let the robot more easily find its way back on track after making a platform turn. We also performed other minor additions. We managed to get the robot to the second platform, successfully performing the intermediate turn operation on the first platform (see Video 7). At some point, however, the robot began failing in detecting the black end line - perhaps due to poor lighting in the later hours of the day, perhaps due to the sensors being raised as they were sometimes scraping on the track, and perhaps simply due to low battery. As black sensing was still working for the other two ongoing implementations, we decided to leave the DifferentialPilot at this.
 
 [TODO: Fix to markdown video format]