Trajectories

The toolbox supports several classes of trajectory functions. They all return an object which hold a collection of signals which are typically output by a trajectory generator.

1D trajectories

Function	Purpose
tpoly	quintic polynomial
lspb	trapezoidal trajectory (linear segment with parabolic blends)

The Trajectory object

Attribute	Type	Meaning
x	ndarray(n)	independent variable (step or time)
y	ndarray(n)	y(x) is position
yd	ndarray(n)	yd(x) is velocity
ydd	ndarray(n)	ydd(x) is acceleration
istime	bool	true if x in units of seconds, affects scaling of yd(x) and ydd(xx)

ND trajectories

Function	Purpose
mtraj	multi-joint wrapper for tpoly or lspb
jtraj	quintic polynomial for multiple joints
mstraj	multi-segment path with waypoints

The Trajectory object

Attribute	Type	Meaning
t	ndarray(n,m)	independent variable (step or time)
q	ndarray(n,m)	q(t) is position
qd *	ndarray(n,m)	qd(t) is velocity
qdd *	ndarray(n,m)	qdd(t) is acceleration
istime	bool	true if x in units of seconds, affects scaling of yd(x) and ydd(xx)

* for jtraj only. qd and add are synonyms for yd and ydd.

The Trajectory object

Method	Meaning
len(T)	n length of trajectory
T.naxes	m number of axes
T.plot()	plot y, yd, ydd on single plot, for 1D trajectories
T.qplot()	multi-axis qplot() with data from this object