Qualitative transition in object reorienting behaviour. 2. The effects of varying the centre of mass

For pt. 1 see Proc. IEEE Int. Conf. on Robotics and Automation, p.2697-704 (1997). We investigate the topology of the space of possible pushing behaviour for 2.5 D objects of arbitrary outline. We do this by studying the push-stability diagram (PSD) derived by Brost (1985, 1988). We show how to predict some of the effects on the topology of the PSD that arise from varying the position of the centre of mass, making it possible to use this as a control parameter in the design of objects for feeding.