Welcome to the Swerve Robotics library for the FTC robot controller runtime. The purpose of our library is to augment the robot controller runtime library from FTC HQ in order to simplify programming for FTC teams. The central aim here is not to change what's there, just to make it better. The library is a drop-in replacement: if your code works with the FTC HQ release, it will work with the Swerve library, but you can also take advantage of new things. Please consult the GitHub release notes for details regarding a given release. You might also want to check out our related project, the Swerve Robotics Tools Suite, also here on GitHub.
Notable features of the Swerve Robotics FTC Library include the following.
EasyLegacyMotorController is a replacement for the stock DCMotorController implementation used with legacy HiTechnic motor controllers. EasyLegacyMotorController does away with the need to manually switch motors from read mode to write mode and back again and the attendant complex delay management, loop counting, or waiting for hardware cycles that that requires. Just call setPower(), getPosition(), or whatever other motor methods you need to use, and the right things happen under the covers.
EasyLegacyMotorController can be used from any OpMode, or indeed any thread. In SynchronousOpModes, EasyLegacyMotorController is used automatically; in other OpModes it can be used by calling ClassFactory.createEasyMotorController().
In a conceptually similar way, alternate implementations for modern motor and servo controllers and for legacy servo controllers is also provided. The API simplifications for these controllers are less dramatic than for the easy legacy motor controller, but are worthwhile nevertheless. Most importantly, reads and writes to these device now happen (virtually) when you issue them, and reads or writes that follow a write are sequenced after that write so as to preserve causality. This simplifies programming. Change a motor mode? Fine, it's changed: anything else you do on that motor will be sure to have seen the effect of that change. You don't have to poll to see whether the mode change has taken effect. Reset the encoders and then immediately change to run with encoders? Perfectly fine. It just works. Additionally, a handful of bug fixes is included. For example, Servo.getPosition() is now functionally useful.
These easy controllers can be used from any OpMode or any thread. In SynchronousOpModes, they are used automatically; in other OpModes, they can be used by calling ClassFactory.createEasyMotorController() or ClassFactory.createEasyServoController() respectively.
The library has an alternate OpMode registration mechanism (the old FtcOpModeRegister.register() still works too) that allows you to register your own OpModes simply by decorating them with @TeleOp or @Autonomous annotations. This helps promote clean living and easier integration of library updates over time by avoiding editing code that lives in libraries owned by others. To register OpModes that aren't your own, a related annotation, @OpModeRegistrar, can be placed on a method in your code which is to be called as part of the registration process. Take a look at the YourCodeHere module for an example of how this works. We'd like to thank dmssargent for illustrating how this all might be technically accomplished.
The library contains a SynchronousOpMode class that brings back the synchronous, linear programming style with which teams have been familiar with from previous seasons in RobotC, and which is more amenable to teaching to beginning programmers than the event-driven / loop() callback programming model native to the robot controller runtime. SynchronousOpMode is similar to LinearOpMode but contains several enhancements, improved robustness, and several fixes. All hardware objects visible in SynchronousOpModes are thread-safe, in that they can be manipulated concurrently by multiple threads without internally becoming confused. SynchronousOpMode also gives you precise control of when changes in gamepad state are made visible to your program, allowing you to safely reason about a given state across a possibly complicated chain of logic. Information on writing in or migrating to SynchronousOpMode is found just below.
The library contains an enhanced form of telemetry containing a dashboard and a log. On the driver station display, the dashboard appears at the top, followed by as many of the recent log messages as will reasonably fit. The dashboard can be preconfigured just once with unevaluated computations to form the lines on the dashboard, and / or the lines can be created dynamically with addData() calls as in the robot controller runtime. You call telemetry.update() to compose the current dashboard and transmit to the driver station. Only a subset of update() calls actually transmit, saving bandwith on the network and data acquistion time on the controller. Log messages can be written to the log at any time, and these are sent to the driver station as soon as possible. The enhanced telemetry class can be used both by synchronous and non-synchronous opmodes, but is used automatically in SynchronousOpModes.
The library contains an I2cDeviceClient class that wraps I2cDevice instances and makes them easy to use by handling read-vs-write mode switches and attendant waits automatically and transparently. Just call read8() or write8() (and friends) to read and write device registers and the rest is taken care of. With the I2C register map you get from the sensor manufacturer in hand, it's now just dead easy to write your own code to talk to new I2C devices. Note that I2cDeviceClient is also decoupled from SynchronousOpMode, in that one need not be using SynchronousOpMode to use I2cDeviceClient. However as some operations are lengthy, a worker thread is suggested in that case in order to avoid long-running operations on the loop() thread.
The library contains a class that is built on I2cDeviceClient that provides a semantic interface to the Bosch BNO055 absolute position sensor, allowing teams to make easy use of the AdaFruit inertial motion unit (IMU) which incorporates that sensor module. Features of this sensor include a gyro that does rate integration in hardware to provide robust and accurate angular position indications, and a separation of the output of the accelerometer into gravity and linear-motion-induced components. The class builds on the latter to provide linear velocity and position measurements using integration in software. That said, the built-in accelerometer integration algorithm is quite naive. For a real robot, you'll want to do some investigation and reading and provide a better one, which you can specify in the initialization parameters for the IMU. Also, while the out-of-box sensor works remarkably well, Bosch describes a one-time calibration process (see Section 3.11) that will make it even better.
The library contains a alternate implemenation of HiTechnic and ModernRobotics color sensors that robustly implements the color sensor semeantics. In particular, the LED works reliably.
The fifteen second summary of how to use SynchronousOpMode is as follows:
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Inherit your opmode from SynchronousOpMode instead of OpMode or LinearOpMode.
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Implement your code in a main() method whose signature is:
@Override protected void main() throws InterruptedException -
Initialize your hardware variables at the top of main() instead of in start(). Otherwise, the use of hardware objects (DcMotor, Servo, GamePads, etc) is the same as in the usual robot controller runtime.
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The core of the body of main() for a typical TeleOp OpMode should look like
// Initialize stuff (not shown) // Wait for the game to start this.waitForStart(); while (this.opModeIsActive()) { if (this.updateGamePads()) { // Do something interesting } telemetry.update(); this.idle(); }
That's it! Autonomous OpModes are even simpler: just write what you want the robot to do after the waitForStart().
Migrating from LinearOpMode to SyncronousOpMode is easy, usually simply involving
- changing the OpMode base class to SynchronousOpMode from LinearOpMode
- changing the name of your runOpMode() method to main()
- adding 'telemetry.update()' and 'this.idle()' to the bottom of your while(opModeIsActive()) loop
- optionally removing waitOneFullHardwareCycle() calls, as they are no longer necessary
The Swerve Library now appears to be quite stable and functional. Our own teams are actively developing their competition code using it. It currently is synchronized to the release from FTC HQ that was published November 4th, 2015. Please be sure to update your driver station app to the latest-available version.
To use the library, we recommend forking or cloning our repository and working off of the 'master' branch. The Swerve Library repository includes the robot controller runtime repository from FTC HQ; you don't need both. While we do tag major milestones in the library and 'release' them, we try to keep the master branch always stable and fully functional, so you could reasonably sync to the latest available if you wished. Alternately, instead of forking or cloning, you can download a full copy of the source in .zip form from one of our releases. If you have previously forked the FTC HQ tree from https://github.com/ftctechnh/ftc_app and you are moderately git-savvy, you can easily upgrade to the Swerve Library by adding a new remote of https://github.com/SwerveRobotics/ftc_app to your git tree and initiating a pull from that remote. If that's greek to you, give us a ring, and we'll help you through it.
Documentation is available in the SwerveRoboticsLibrary/doc/javadoc directory. There are also several examples of using the library to be found in the 'examples' package.
We'd love to hear what you think about the library. Thanks!
Robert Atkinson,
[email protected],
Mentor, Swerve Robotics,
Woodinville, Washington
(The remainder of this file is as published by FTC headquarters.)
FTC Android Studio project to create FTC Robot Controller app.
This is the FTC SDK that can be used to create an FTC Robot Controller app, with custom op modes. The FTC Robot Controller app is designed to work in conjunction with the FTC Driver Station app. The FTC Driver Station app is available through Google Play.
To use this SDK, download/clone the entire project to your local computer. Use Android Studio to import the folder ("Import project (Eclipse ADT, Gradle, etc.)").
Documentation for the FTC SDK are included with this repository. There is a subfolder called "doc" which contains several subfolders:
- The folder "apk" contains the .apk files for the FTC Driver Station and FTC Robot Controller apps.
- The folder "javadoc" contains the JavaDoc user documentation for the FTC SDK.
- The folder "tutorial" contains PDF files that help teach the basics of using the FTC SDK.
For technical questions regarding the SDK, please visit the FTC Technology forum:
http://ftcforum.usfirst.org/forumdisplay.php?156-FTC-Technology
Release 15.11.04.001
- Added Support for Modern Robotics Gyro.
- The GyroSensor class now supports the MR Gyro Sensor.
- Users can access heading data (about Z axis)
- Users can also access raw gyro data (X, Y, & Z axes).
- Example MRGyroTest.java op mode included.
- Improved error messages
- More descriptive error messages for exceptions in user code.
- Updated DcMotor API
- Enable read mode on new address in setI2cAddress
- Fix so that driver station app resets the gamepads when switching op modes.
- USB-related code changes to make USB comm more responsive and to display more explicit error messages.
- Fix so that USB will recover properly if the USB bus returns garbage data.
- Fix USB initializtion race condition.
- Better error reporting during FTDI open.
- More explicit messages during USB failures.
- Fixed bug so that USB device is closed if event loop teardown method was not called.
- Fixed timer UI issue
- Fixed duplicate name UI bug (Legacy Module configuration).
- Fixed race condition in EventLoopManager.
- Fix to keep references stable when updating gamepad.
- For legacy Matrix motor/servo controllers removed necessity of appending "Motor" and "Servo" to controller names.
- Updated HT color sensor driver to use constants from ModernRoboticsUsbLegacyModule class.
- Updated MR color sensor driver to use constants from ModernRoboticsUsbDeviceInterfaceModule class.
- Correctly handle I2C Address change in all color sensors
- Updated/cleaned up op modes.
- Updated comments in LinearI2cAddressChange.java example op mode.
- Replaced the calls to "setChannelMode" with "setMode" (to match the new of the DcMotor method).
- Removed K9AutoTime.java op mode.
- Added MRGyroTest.java op mode (demonstrates how to use MR Gyro Sensor).
- Added MRRGBExample.java op mode (demonstrates how to use MR Color Sensor).
- Added HTRGBExample.java op mode (demonstrates how to use HT legacy color sensor).
- Added MatrixControllerDemo.java (demonstrates how to use legacy Matrix controller).
- Updated javadoc documentation.
- Updated release .apk files for Robot Controller and Driver Station apps.
T. Eng November 5, 2015
Release 15.10.06.002
- Added support for Legacy Matrix 9.6V motor/servo controller.
- Cleaned up build.gradle file.
- Minor UI and bug fixes for driver station and robot controller apps.
- Throws error if Ultrasonic sensor (NXT) is not configured for legacy module port 4 or 5.
T. Eng October 6, 2015
In this latest version of the FTC SDK (20150803_001) the following changes should be noted:
- New user interfaces for FTC Driver Station and FTC Robot Controller apps.
- An init() method is added to the OpMode class.
- For this release, init() is triggered right before the start() method.
- Eventually, the init() method will be triggered when the user presses an "INIT" button on driver station.
- The init() and loop() methods are now required (i.e., need to be overridden in the user's op mode).
- The start() and stop() methods are optional.
- A new LinearOpMode class is introduced.
- Teams can use the LinearOpMode mode to create a linear (not event driven) program model.
- Teams can use blocking statements like Thread.sleep() within a linear op mode.
- The API for the Legacy Module and Core Device Interface Module have been updated.
- Support for encoders with the Legacy Module is now working.
- The hardware loop has been updated for better performance.
T. Eng August 3, 2015