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New in v0.7

Version v0.7 is a dramatic reduction in scope from the previous versions. The focus starting from this version is to provide a simple API for defining trajectory optimization problems, leaving the task of evaluating and solving these to the solvers that wish to consume the Problem type.

Some notable changes:

  • Problem constructor now has x0 as position argument and xf as keyword argument
  • The Problem type now stores a vector of RobotDynamics.DiscreteDynamics models, allowing for changing dynamics models (i.e. hybrid dynamics) along the trajectory.
  • Objectives no longer multiply "stage" costs by the time step automatically. This is left up to the user.
  • The package no longer provides methods to evaluate cost or constraint expansions for the entire problem. Types such as AbstractConstraintVals or CostExpansion have been removed.
  • The package no longer provides native support for MathOptInterface. This functionality should be implemented by the solvers themselves.

New in v0.6

v0.6.2

Treats equality constraints as cones. Fixes deprecation warnings and small API changes from RobotDynamics v0.4.3, including:

  • Replacing Traj with SampledTrajectory
  • Using RobotDynamics.dims instead of Base.size
  • Using RobotDynamics.errstate_jacobian! instead of RobotDynamics.state_diff_jacobian!

Updated to new RobotDynamics v0.4 API

Allows for both inplace and out-of-place dynamics, cost, and constraint evaluations. Jacobians can be calculated using finite differences, forward AD, or user-specified. Avoids prohibitively long compilation times for larger state and control dimensions.

  • Replaced length and size methods with state_dim, control_dim, output_dim and dims.
  • Problem constructor is now of the form Problem(model, obj, xf, tf, [x0, constraints]) Note that x0is now a required positional argument andxf` is an optional keyword argument.
  • Integration for dynamics is now specified by the model instead of a type parameter.
  • Support for direct collocation via MathOptInterface has been removed (will be implemented in a separate repo in the future)

New in v0.5

Support for Finite Differencing

Added support for finite differencing with FiniteDiff for dynamics, constraints, and cost functions.

Added general nonlinear costs

Generic nonlinear costs are now officially supported and can be automatically differentiated using either ForwardDiff or FiniteDiff.

Added generic Expansion type

The new Expansion type is provided for storing cost expansions, and is now preferred for use over QuadraticCost. It supports both xx,xu,uu,x,u and Q,H,R,q,r fields. In general, the way cost functions were used has been cleaned up. QuadraticObjective and other such type aliases have been removed in favor of a less complicated API.

Expanded Documentation

Documentation has been significantly updated.

New in v0.4

Conic Constraints

TrajectoryOptimization now add support for generalized inequalities / conic constraints. As of 0.4.0 only 2 cones are implemented:

  • NegativeOrthan - equivalent to Inequality
  • SecondOrderCone

Several constraints, most notably NormConstraint support passing in SecondOrderCone as the sense argument, which enforces that the output of the evaluate function lies in the second-order cone, with the last element of the vector being the scalar.

Created the AbstractConstraintValues super-type

This allows solvers to define their own instantiations of this type, while providing many convenient methods automatically defined on the super-type.

Added Cost Function for Rotations

Added DiagonalLieCost that penalizes the geodesic distance between a quaternion in the state and a reference quaternion.