The mutexes in PIDControllerRunner are declared after the Notifier, and
when the PIDControllerRunner object is destructed, the member object
destructors are called in the reverse order in which they are declared.
The mutexes are destructed first, then the Notifier destructor is called
which stops the Notifier.
There's a window between those destructor calls during which the
Notifier can run the callable and attempt to lock a mutex that no longer
exists.
Declaring the Notifier after all the variables its callable uses fixes
this issue, as it ensures the Notifier is destructed first.
These classes introduce ways to represent poses and provide easy ways to transform, rotate, and translate poses across 2d space. This classes will be especially useful for a planned odometry and kinematics suite.
Furthermore, these classes can also be used to simply represent waypoints on a field, do superstructure motion planning, etc.
SampleRobot provides no benefits over RobotBase to advanced teams and
TimedRobot is recommended for everyone else.
A skeleton template for RobotBase was added.
Originally, PIDController used PIDSource with its "PIDSourceType" to
determine whether a class should return position or velocity to the
controller. However, the supported languages have changed a lot over 10
years and now support lambdas. Instead of using PIDSource and PIDOutput,
users can pass in doubles to the Calculate() function synchronously.
This makes the controller much more flexible for team's needs as they no
longer have to make a separate PIDSource-inheriting class just to
provide a custom input.
The built-in feedforward was removed. Since PIDController is synchronous
now, they can add their own feedforward on top of what Calculate()
returns.
To facilitate running the controller asynchronously, there is a
PIDControllerRunner class that handles that. By separating the loop from
the control law, PIDController can now be composed with others and be
used to control a drivetrain (a multiple input, multiple output system
that requires summing the results from two controllers) much easier.
Also, motion profiling can be used to set the reference over time.
All the classes related to the old PIDController are now deprecated. The
new classes are in an experimental namespace to avoid name conflicts.
While this is a large change, I think it is a necessary one for growth.
The old PIDController design was created in a time when languages only
supported OOP, and we have more tools at our disposal now to solve
problems. This more versatile implementation can be used in more places
like as a replacement for Pathfinder's "EncoderFollower" class.
There has been hesitation to add lambda support to WPILib for a while
now out of concerns for requiring teams to learn more features of C++ or
Java. In my opinion, this change makes PIDController easier to use, not
harder. The concept of a function is a building block of OOP and should
be learned before classes. The ability to store functions as first-class
objects and invoke them just like variables is rather natural.
Note that PID constants for the new controller will be different from
the old one. The original controller didn't take the discretization
period into account. To fix this, teams should just have to divide their
Ki gain by 0.05 and multiply their Kd gain by 0.05 where 0.05 is the
original default period.
* Renamed LinearDigitalFilter to LinearFilter
* Filter base class removed since it wasn't useful
* C++: std::shared_ptr<> replaced with double parameter
When there is more than one ultrasonic sensor, only the last sensor
instantiated would work due to incorrect array index management. This
replaces the previous approach with range-based for loops like the C++
implementation.
Supersedes #1589.
Resetting the flag should only occur in Enable() and Reset().
IterativeRobotBase needs the flag to remain set to print epochs after
disabling the Watchdog.
Add a Sendable wrapper for VideoSource objects.
Add convenience methods for adding video sources directly to containers
so users won't have to manually wrap video sources.
The 2019 FPGA image switched the output of auto SPI from plain bytes to a
sequence of 32-bit words (timestamp, then words with the byte values in the
least significant byte of each word).
In addition to changing the HAL and simulators to reflect this, add piecewise
integration support to wpilibc/wpilibj SPI to take advantage of the timestamps
and use it in the ADXRS450 gyro.
Notifier has one thread per instance because the callbacks must be
asynchronous. Watchdog callbacks can be synchronous, so this overhead
can be done away with via a scheduler thread akin to what the HAL
Notifier does.
