The Role and Implementation of Compliance in Legged Locomotion

摘要

Many robots excel at precise positioning and trajectory tracking using software control, and most successful robotic applications utilize this ability—examples include CNC machining, robotic welding, painting, and pick-and-place circuit board assembly. The mechanical design of these robots focuses on rigid transmissions and minimizing compliance in the structure, so the software controller can accurately track a desired position as a function of time, regardless of any disturbance forces. However, there is a class of tasks for which rigid actuation is not ideal: physical interaction with the world, especially interaction that involves an impact or kinetic energy transfer. Animals tend to excel at these tasks, and far outperform the best robots. Examples include walking, running, catching a ball, gripping a piece of fruit firmly but without causing damage, and many types of assembly tasks. For dynamic behaviors such as running, the performance limitations of a robot are often due to limitations of the mechanical design. A robot is an integrated system of electronics, software, and mechanism, and each part of the system limits or enables the behavior of the whole. While some behaviors can easily be implemented through simple actuators and direct software control, a running machine requires mechanical design that is specialized for the task. Among other things,