This is a move-only variant of std::function to support move-only captures.
Imported from LLVM with some small tweaks (changed to 4 pointer internal storage, warnings fixes).
SampleRobot provides no benefits over RobotBase to advanced teams and
TimedRobot is recommended for everyone else.
A skeleton template for RobotBase was added.
std::scoped_lock was introduced in C++17 and is strictly better than
std::lock_guard as it supports locking any number of mutexes safely.
It's also easier to use than std::lock for locking multiple mutexes at
once.
Timer didn't have working move semantics because mutexes aren't
moveable, meaning the default implementations were ill-formed.
MotorSafety wasn't locking its mutex.
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.
This can be dangerous as it refers to a temporary, and GCC 9.0 warns about
its use. Instead add std::initializer_list overloads to common places it
was used in an initializer_list sense.
* Renamed LinearDigitalFilter to LinearFilter
* Filter base class removed since it wasn't useful
* C++: std::shared_ptr<> replaced with double parameter
* ErrorBase: Use magic static singleton for globals
* ErrorBase: Add testability features for global errors
* Make WPIError definitions inline functions
(This works around cross-DLL variable issues on Windows)
Fixes#1726.
The current versions of the RoboRIO and Raspbian compilers support the flag but have
minimal actual C++17 support. Changing the flag is the first step.
