Abstract
The purpose of this paper is to develop a fundamental external force detection framework for construction manipulator. Such industrial application demands practicality that satisfies detection requirements such as accuracy and robustness while ensuring (i) low cost, (ii) wide applicability, and (iii) simple detection algorithm. To satisfy (i) and (ii), our framework adopts hydraulic sensors as force sensor. Hydraulic sensor essentially detects error force components that generate depending on joint kinetic state and differ in identification- difficulty due to nonlinear and uncertain hydromechanical system. To satisfy (ii) and (iii), theoretical, experimental, and conditional identification methods without complex modeling are applied in static, uniform motion, and accelerated motion states for identifying self-weight, driving, inertial forces defined as dominant error components. Experiments were conducted using our instrumented hydraulic arm system. Result of no-load task indicates that our framework lowers a threshold to determine the on-off state of external force application, independent of joint kinetic states. Result of on-load task confirms that our framework robustly identifies off states in which external force is not applied to hydraulic cylinder.
