[ODE] dJointFeedback

[Umberto]

Hi all,

I'm having some problems with dJointFeedback. I have 7 bodies linked with 
hinge joints and I want to know the torque applied by the servo-motors 
attached to the joints.
Each timestep I get the torque applied by each joint, the hinge axis and 
then multiply (dot product) them together. That should be correct.

The problem are:
- torque is non-zero also in directions othogonal to hinge axis
- torque oscillates in a strange way from positive to negative values (or 
viceversa). I paste some values:

   time               torque0                         torque1 
            torque2                         torque3 
torque4                         torque5                         torque6
  1.310	        0.0076027802	      150.0000000004	      106.1554142243 
   44.0251749728	       -7.7392418344	        0.0932724948	        0.0008941327
  1.315	        0.7633255649	     -149.9999999998	     -108.3712880812 
  -44.5613336915	        7.3001007482	       -0.8755813712	        0.0062378639
  1.320	       -0.5497119522	       62.9098111211	       47.6548833165 
   20.9117353229	       -3.3865153547	        0.6084439383	       -0.0041544231
  1.325	        0.6507040180	     -149.9999999999	     -108.1542116000 
  -44.4827044946	        7.3382073138	       -0.7963714105	        0.0047561220
  1.330	       -0.6944688825	       62.3186569197	       48.0555701973 
   21.3558062112	       -3.3820023868	        0.7689960510	       -0.0048837283
  1.335	        0.6526032571	     -150.0000000001	     -108.4675298662 
  -44.7549022566	        7.3703919306	       -0.8349714467	        0.0043723021
  1.340	       -0.6617986446	       97.7628894002	       73.1153787632 
   31.6829790559	       -5.1849405327	        0.8013286997	       -0.0041803923
  1.345	        0.6921515281	     -149.9999999998	     -108.9487730715 
  -45.1422689704	        7.4015824444	       -0.9115690280	        0.0042625978
  1.350	       -0.7101037715	       97.8345253379	       73.6143093942 
   32.0665019895	       -5.2161258095	        0.8761110947	       -0.0042077455
  1.355	        0.7343131413	     -150.0000000002	     -109.4477914240 
  -45.5388802442	        7.4321122782	       -0.9912305308	        0.0042214666
  1.360	       -0.7553457502	       97.8904180551	       74.0892190719 
   32.4368892596	       -5.2466596311	        0.9482121716	       -0.0042009010
  1.365	        0.7776530200	     -149.9999999998	     -109.9536957483 
  -45.9393377617	        7.4623940312	       -1.0724741399	        0.0041972813
  1.370	       -0.7993068174	       97.9483571484	       74.5615908101 
   32.8047854019	       -5.2772656864	        1.0194585834	       -0.0041851887
  1.375	        0.1040565142	      150.0000000002	      107.2688608829 
   44.8933605207	       -7.8009760517	        0.2293462858	        0.0006964118
  1.380	        1.1525334913	     -150.0000000003	     -112.1380290476 
  -47.5722632890	        7.5333245877	       -1.4889148516	        0.0059850708
  1.385	       -1.3490948322	      -63.9096622449	      -37.9233418094 
  -12.7013599982	        2.8077303603	        1.2197503385	       -0.0072224677
  1.390	        0.9272890864	     -149.9999999998	     -111.3146000643 
  -46.9898259739	        7.5315264948	       -1.2997531772	        0.0046109816
  1.395	       -0.9130895920	       83.5432124086	       65.2578844124 
   29.3404513221	       -4.6077619046	        1.1514653473	       -0.0042768474
  1.400	        0.9231847580	     -149.9999999999	     -111.5638261478 
  -47.2035446365	        7.5544689581	       -1.3345748467	        0.0042519146
  1.405	       -0.9186870966	       98.1271205510	       75.9305766622 
   33.8695483317	       -5.3676683849	        1.2231390129	       -0.0040723803
  1.410	        0.9532323579	     -150.0000000002	     -112.0048361053 
  -47.5546168220	        7.5823765390	       -1.4042605434	        0.0041476076
  1.415	       -0.9672950184	       98.1787428128	       76.4308634519 
   34.2573280221	       -5.3985063214	        1.3007640832	       -0.0040954541
  1.420	        0.9914350692	     -149.9999999998	     -112.4922724838 
  -47.9384100626	        7.6113466490	       -1.4825820023	        0.0041068398
  1.425	       -1.0104851481	       98.2321777139	       76.9062678727 
   34.6260457508	       -5.4286688454	        1.3733667275	       -0.0040864558
  1.430	        0.1500972819	      150.0000000002	      108.3061696249 
   45.6937072153	       -7.8522313252	        0.3803349635	        0.0007250653
  1.435	        1.4564334144	     -150.0000000003	     -115.2344310209 
  -50.0274233993	        7.7211575743	       -1.9957869719	        0.0058624701

it seems like the hinges axis direction is switched from (for example) +Y 
to -Y each timestep.
Any help appreciated.

Thanks
Cheers