Position control with Jrk 12v12


we would like to use the JRK 12v12 to perform position control over a steering wheel, controlling the angle at which the wheel is directed, e.g. we would like to tell the Jrk to steer the wheel at 45° and have the wheel directet toward that angle.

Our system is build up with an Encoder Detector (http://www.bitsbox.co.uk/data/HLC2701.pdf) and an encoder disk with intermittent black radial lines which are used to measure “ticks” of the disk (the disk is similar to this one http://robotgestation.com/images/encoderdisk1.gif, with a more dense distribution of lines than that); the encoder sistem setup is like this http://www.vexforum.com/wiki/images/2/22/Optical_Shaft_Encoder_Figure_2.jpg. For this kind of approach, we use the Frequency (digital) feedback mode of the Jrk.

Assinging 0 ticks to an angle of reference and N ticks to the maximum angle permitted, we would like to link the rotation of the disk (knowing, if necessary, the direction with which the motor spin) to the number of ticks detected, and finally link the latter to the “target” the jrk has to reach. In this case, if the target of the jrk is, say, 135 ticks (corresponding to an angle X) from the reference angle, we would like the jrk to drive the steering wheel to that angle, and then stop or mantain that position. The Jrk should then “keep count” of the ticks, and know the rotation of the disk in respect to the reference angle.

Is the Jrk suitable for this kind of application? Should we use other means to get rotative positionalecontrol (like the one mentioned in this post https://forum.pololu.com/t/simple-motor-controller-18v7-no-longer-powers-motor/3634/8)?

Thank you very much for your help,


Hello, CasterBot.

Unfortunately, the jrk can not do exactly what you want it to do. The “Frequency (digital)” feedback mode is only designed for speed control, not position control. The analog voltage feedback mode works for position control, so if you could connect a potentiometer to the axle of the steering wheel you could get position control.