Passive Tool Changer Development for an Elastic and Compliant Manipulator

Robotic tool changers allow the use of multiple tools or end-effectors by a robotic manipulator and eliminate the need for human intervention to change tools. In this paper, we present the design and testing of a passive mechanical tool changer designed for a project involving the inspection of an acidic and radioactive air duct. The tool changer relied on the active/passive motions of a compliant manipulator to perform tool changes and contains no electrical or pneumatic components. The resulting tool changing operation utilizes a developed compliant controller that relies exclusively on contact forces to guide the manipulator, and thus eliminates the need for precision operation or any assistance from the operator. The design features a locking system to ensure secure storage of tools that are not in use. Furthermore, the connection mechanism includes a bore scope camera for use when tools are not attached or to visually verify tool connections. Testing and demonstrations were performed to validate both the design and operation as well as show both the tools and tool changer perform in an extreme environment. The design requirements, iterative process, and prototype testing with the manipulator are also discussed.