tailieunhanh - Anatomy of a Robot Part 4

Tham khảo tài liệu 'anatomy of a robot part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 46 CHAPTER TWO Nonlinear elements We have to realize that our model depends on a linear behavior of all the components. We expect a smooth performance all the way around. Between loose pieces that might move free and then snap tight and some digital elements that are on-off some jerky motion will occur. Try to minimize the effect of these components we ll look at nonlinear design in a while. Too much overshoot Sometimes a system will move the robot too far and be unable to recover. Such a situation occurred in the introduction where a robot moved too far in one single motion and its limited eye was not given time to see that it passed the boundary where it was supposed to stop. Such a situation can occur if there is too much overshoot. One solution is to increase the damping on the system. Complex designs Often the robot is much more complex than our second-order system. If it really is a third-order or higher system take the time to try to simplify it. Look at the performance and look at the specifications. Let me give you an example of trouble brewing. Suppose we are trying to design a baseball robot. It has to run catch and throw. It might be able to run and catch at the same time but it would be simpler to build a robot that would run under the ball stop and then catch it. Similarly it would be simpler if the robot would stop running before it had to throw the ball. Granted a human baseball player would never get to the majors playing like that. However if the specifications and performance requirements can be relaxed ahead of time and if we can afford to have a clunky robot player then our design will be much simple if you can partition the design. We then just separately design a runner a catcher and a thrower. We do not have to combine the designs and suffer the interactions that drive up complexity and threaten the stability of our design. Again we repeat the old advice Keep it simple. You laugh about robots playing baseball Just keep your eyes on the minor