From the designs usually shown of rocker bogie systems, the whole weight of platform seems to be supported by only one rod, be it differential bar or gear. Isn't this a bit unstable system because if we have arms of rover at one end we will have a high torque about that rod?

Is my understanding such rocker bogie systems correct? If so, are there any solutions to this problem which don't sacrificing the functionality of rover?

To clarify, I want to know how rovers like curiosity are designed so as to balance such a heavy platform with a differential bar mechanism. I am trying to make a small rocker bogie myself and I want to avoid this anticipated problem.

  • $\begingroup$ Hi Shivam, and welcome to Robotics.SE. Your question is a little vague; what do you mean by "better design"? What are your criteria? Is there a practical problem that you're attempting to solve? $\endgroup$
    – Ian
    Nov 8, 2013 at 6:22
  • $\begingroup$ i want to ask how rovers like curiosity modify the design so as to balance so much heavy platform in differential bar mechanism. i am trying to make a small rocker bogie myself and i am thinking about this problem. $\endgroup$
    – Shivam
    Nov 9, 2013 at 7:23
  • $\begingroup$ Welcome to Robotics Shivam. I have edited your question to make it less like an Unbounded Design Question and focus on the problem you anticipated having. $\endgroup$
    – Mark Booth
    Jan 29, 2014 at 23:51

1 Answer 1


This should only be a problem if you anticipate that the weight would be shifting within the robot.

You're correct that the weight of the rover will be borne by the single contact points on each side, so any imbalance about that rod will become stress on the differential mechanism. However, in the initial design of the vehicle you should be placing the contact points of the suspension system in line with the vehicle body's center of mass. You could also add weight to certain parts of the vehicle to achieve this balance.

In cases where you really do want to change the weight distribution in the vehicle (e.g. picking up an object with a gripper arm), you have 2 choices: either make the suspension strong enough to handle the torque you'll be putting on it, or introduce a system that can adjust the balancing point -- a movable ballast.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.