Towards A Novel Technique To Dynamic Path Synthesis

Hybrid actuation mechanisms or robots consist of two types of motors:constant velocity (CV) motor and servo (SV) motor. The CV motor can produce a large power but with a poor task flexibility. On the other hand, the SV motor has an excellent task flexibility but with a small power capacity. Combination of these two types of motors into a coherent driver architecture for machine systems is extremely promising, because two actuation systems complement each other. The hybrid actuation mechanisms can therefore take the advantage of the complementary characteristics of both types of motors to generate a motion which is high task adaptive and of high power capacity in low costs.Since the first publication of the idea of hybrid actuation systems by Tokuz in1992, there have been many studies on such a system. However, nearly most of these studies were pivoted in the traditional mechanism design theory. In this thesis, a new paradigm of design of hybrid actuation systems is formulated, in which both mechanism and robot design theories and methodologies are combined. Further, the current state of arts of design of hybrid actuation systems is such that the theory has a little to consider dynamics which includes stiffness, inertia, damping and seems to be only suitable to five or seven bar mechanisms.In particular, this thesis presents three novel works with respect to the existing literature. First, an observation on the nature of inverse kinematics for hybrid actuation system has been made. A relevant finding is that for a hybrid actuation robot, there may be three cases for inverse kinematics:no solution, definite solution, and infinite number of solutions or indefinite solutions. The second finding is that the path generation problem needs inverse kinematics for a hybrid actuation system. Second, a general approach to inverse kinematics of hybrid actuation systems with any number of links and any number of motors has been developed. As a side finding, a general approach to Assur Groups for gear-bar linkages has been developed. Last, a general methodology to the path generation problem with hybrid actuation robots has been proposed, in which dynamics of the system is considered, which leads to a more accurate result. The thesis has advanced the state of arts of design of robots for path generation in that it extends the scope of the type of mechanisms or robots-i.e., hybrid actuation mechanism in addition to two traditional mechanisms (CV motor only mechanism and servo motor only mechanism).