Dimensional synthesis and topological analysis of a novel transformable wheel-legged hexapod with multi-morphology and vary-topology characteristics

• Multiple characteristics of morphologies are consolidated into a unified mathematical model. • Comprehensive dimensional synthesis based on multi-morphology characteristic is analyzed. • In-depth morphological analysis based on vary-topology characteristic is conducted. • The distribution patterns of foot-tip and hip joints within the workspace are summarized. Multi-morphology robot is one of the most promising solutions to enhance the terrain adaptability of mobile robots. To tackle the challenge posed by the multi-morphology and vary-topology characteristics in design and analysis of mechanisms, this paper proposes a multi-morphology dimensional synthesis and vary-topology morphological analysis strategy based on a transformable wheel-legged hexapod (TWLHex), using the performance chart-based design methodology (PCbDM). First, the kinematic model of is established. Second, the PCbDM is applied for dimensional synthesis in response to the multi-morphology characteristic. Third, sensitivity analysis is performed followed by the performance distribution evaluation of the hip joints and the foot-tips within the workspace, based on the optimized dimensions. Fourth, the PCbDM is used for the morphological analysis considering the vary-topology characteristic. Finally, the optimized dimensions, priority of position error sensitivity, performance distribution trends, and morphological distribution patterns are obtained. This work not only firstly introduces the concept of vary-topology into the research of multi-morphology robots, but also applies the PCbDM to multi-morphology robots, providing new insights for multi-morphology and vary-topology synergistic design.