Trajectory generator¶

This chapter describes the TrajectoryGenerator interface. It represents an entity which calculates movement trajectories. Different types of trajectory generator are available, such as: trajectory generators for 3rd order trajectories, 4th order, or with/without end-point-correction.

Signals¶

Signals present for all trajectory generator types are listed in table Generic trajectory generator signals. Depending on the type of trajectory generator, additional signals may be available.

Generic trajectory generator signals¶
Name	Data type	R/W	Description
MaximumVelocity	Float	RW	Maximum velocity used for calculating new trajectories
MaximumAcceleration	Float	RW	Maximum acceleration used for calculating new trajectories
MaximumJerk	Float	RW	Maximum jerk used for calculating new trajectories
QuickstopDeceleration	Float	RW	Deceleration used for calculating quickstop trajectories
TrajectoryIsCalculating	Bool	R	Trajectory generator is busy calculating a new trajectory
TrajectoryCount	UInt32	R	Total number of calculated trajectories since last power up
TrajectoryAverageTime	Float	R	Average trajectory calculation time since last power up
TrajectoryMaximumTime	Float	R	Maximum trajectory calculation time since last power up

Note

Demand* signals of the TrajectoryInterpolator are bounded by design by their corresponding Maximum* signal, but may exceed them by at most std::nextafterf(value, inf) due to numerical processing and internal datatype conversions.

As an example:

Example explaining how a maximum value can be exceeded¶
Type	Value
Original	0.1
Float-equiv	0.100000001490116119384765625
Next-float-equiv	0.10000000894069671630859375

Hence in this example, when writing double value = 0.1 to one of these Maximum* signals, the corresponding Demand* signal is actually bounded by ~0.1000000089.