added argparser, can specify backend and robot model from command line

Author: petercorke

examples/puma_jtraj.py

@@ -1,18 +1,46 @@
 import roboticstoolbox as rtb
 from spatialmath import *   # lgtm [py/polluting-import]
+import argparse
+import sys
 
+parser = argparse.ArgumentParser(description="Puma trajectory demo")
+parser.add_argument('--backend', '-b', dest='backend', default='pyplot', 
+	help='choose backend: pyplot (default), swift, vpython', action='store')
+parser.add_argument('--model', '-m', dest='model', default='DH', action='store',
+	help='choose model: DH (default), URDF')
+args = parser.parse_args()
+
+if args.model.lower() == 'dh':
+	robot = rtb.models.DH.Puma560()
+elif args.model.lower() == 'urdf':
+	robot = rtb.models.URDF.Puma560()
+else:
+	raise ValueError('unknown model')
 
-#robot = rtb.models.URDF.Puma560()
-robot = rtb.models.DH.Puma560()
 print(robot)
-print(robot.fkine(robot.qz))
-# tw, T0 = p560.twists(p560.qn)
-# print(tw)
+
 qt = rtb.tools.trajectory.jtraj(robot.qz, robot.qr, 200)
-robot.plot(qt.q, dt=0.1, block=True) #movie='puma_sitting.gif')
-#swift = rtb.backend.Swift()
-#swift.launch()
-#swift.add(robot)
-#for q in qt.q:
-	#robot.q = q
-	#swift.step()
+
+if args.backend.lower() == 'pyplot':
+	if args.model.lower() != 'dh':
+		print('PyPlot only supports DH models for now')
+		sys.exit(1)
+	backend = rtb.backends.PyPlot()
+elif args.backend.lower() == 'vpython':
+	if args.model.lower() != 'dh':
+		print('VPython only supports DH models for now')
+		sys.exit(1)
+	backend = rtb.backends.VPython()
+elif args.backend.lower() == 'swift':
+	if args.model.lower() != 'urdf':
+		print('Swift only supports URDF models for now')
+		sys.exit(1)
+	backend = rtb.backends.Swift()
+else:
+	raise ValueError('unknown backend')
+
+backend.launch()
+backend.add(robot)
+for q in qt.q:
+	robot.q = q
+	backend.step(0.1)